11,694 results
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2. A simple synthesis method to produce metal oxide loaded carbon paper using bacterial cellulose gel and characterization of its electrochemical behavior in an aqueous electrolyte.
- Author
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Miyajima, Naoya, Jinguji, Ken, Matsumura, Taiyu, Matsubara, Toshihiro, Sakane, Hideto, Akatsu, Takashi, and Tanaike, Osamu
- Subjects
- *
METALLIC oxides , *CARBON paper , *CHEMICAL synthesis , *CELLULOSE , *AQUEOUS electrolytes , *ELECTROCHEMISTRY , *CARBONIZATION - Abstract
A simple synthetic chemical process to produce metal oxide loaded carbon papers was developed using bacterial cellulose gel, which consisted of nanometer-sized fibrous cellulose and water. Metal ions were successfully impregnated into the gel via aqueous solution media before drying and carbonization methods resulting in metal oxide contents that were easy to control through variations in the concentration of aqueous solutions. The papers loaded by molybdenum oxides were characterized as pseudocapacitor electrodes preliminary, and the large redox capacitance of the oxides was followed by a conductive fibrous carbon substrate, suggesting that a binder and carbon black additive-free electrode consisting of metal oxides and carbon paper was formed. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
3. Upcycling of waste paper and cardboard to textiles.
- Author
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Ma, Y., Hummel, M., Määttänen, M., Särkilahti, A., Harlin, A., and Sixta, H.
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PAPER recycling , *BIODEGRADATION , *POLYMERS , *CHEMICAL synthesis , *BIOPOLYMERS , *CARDBOARD , *WASTE paper , *IONIC liquids - Abstract
In continuation of previously reported results, the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene-1-ium acetate was also found to be a powerful non-derivatizing solvent for cellulosic waste such as paper and cardboard. The ionic liquid could dissolve all the present bio-polymers (cellulose, hemicellulose, and lignin) in high concentrations, resulting in solutions with visco-elastic properties that were suitable for dry-jet wet fiber spinning. The cellulosic raw materials were refined gradually to identify the influence of residual components on the spinnability of the respective solution. Polymer degradation and losses in the spinning process could be avoided nearly entirely. With the exception of virtually unrefined cardboard, all the samples showed excellent spinnability, resulting in fibers with high tensile strength. Prototype textiles were produced to validate the quality of the fibers and demonstrate the possibility of using residual lignin in cardboard as a natural dye. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
4. Synthesis of Zeolitic Material with High Cation Exchange Capacity from Paper Sludge Ash Using EDTA
- Author
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Takaaki Wajima
- Subjects
Technology ,cation exchange capacity ,QH301-705.5 ,Abundance (chemistry) ,QC1-999 ,Tobermorite ,Ethylenediaminetetraacetic acid ,Chemical synthesis ,chemistry.chemical_compound ,Cation-exchange capacity ,zeolite-A ,General Materials Science ,Chelation ,Biology (General) ,Zeolite ,QD1-999 ,Instrumentation ,Fluid Flow and Transfer Processes ,Chemistry ,Physics ,Process Chemistry and Technology ,EDTA ,General Engineering ,Engineering (General). Civil engineering (General) ,Alkali metal ,paper sludge ash ,Ca-masking ,Computer Science Applications ,TA1-2040 ,Nuclear chemistry - Abstract
Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content because of the presence of calcite fillers, which interfere with the zeolitic conversion of PSA. Ca-masking with ethylenediaminetetraacetic acid (EDTA) was used to reduce Ca interference during zeolite synthesis so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Hydroxysodalite, zeolite-P, hydroxycancrinite, tobermorite, and zeolite-A can be synthesized from PSA by an alkali reaction with EDTA. With the addition of EDTA, calcium ions in the solution were trapped by chelation, and the number of zeolitic crystals with low Si/Al (Si/Al = 1), zeolite-A, increased owing to the promotion of the synthesis reaction. A product with a high CEC that has a high zeolite-A content was obtained. The chelating agent can inhibit Ca interference for zeolite synthesis by Ca-masking, and a product with a high zeolite-A content can be obtained from PSA using EDTA.
- Published
- 2021
- Full Text
- View/download PDF
5. Phenotypically distinguishing ESBL-producing pathogens using paper-based surface enhanced Raman sensors.
- Author
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Hilton, Shannon H., Hall, Connor, Nguyen, Hieu T., Everitt, Micaela L., DeShong, Philip, and White, Ian M.
- Subjects
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SERS spectroscopy , *LACTAMS , *BETA lactam antibiotics , *MEDICAL microbiology , *MULTIDRUG resistance , *DETECTORS , *CHEMICAL synthesis - Abstract
Antimicrobial stewardship practices are critical in preventing the further erosion of treatment options for bacterial infections. Yet, at the same time, determination of an infection's antimicrobial susceptibility requires multiple rounds of culture and expensive lab automation systems. In this work, we report the use of paper-based surface enhanced Raman spectroscopy (SERS) sensors and portable instrumentation to phenotypically discriminate multi-drug resistance with fewer culture steps than conventional clinical microbiology. Specifically, we demonstrate the identification of resistance to varying generations of β -lactam antibiotics by detecting the activity of particular β -lactamase enzymes in a multiplexed assay. The method utilizes molecular reporters that consist of β -lactams with SERS barcodes. Hydrolysis of the β -lactam by β -lactamase enzymes in the sample expels the barcode; the released sulfur-containing barcode is then detected via SERS. Using this approach, we demonstrate the differentiation of E. coli strains with (1) extended spectrum β -lactamase (ESBL), (2) narrow-spectrum β -lactamase, and (3) no resistance, using only a single measurement on a single sample. In addition, we experimentally validate an approach to expand the library of reporters through the simple chemical synthesis of new barcoded β -lactams. Importantly, the reported method determines the susceptibility based on phenotypic β -lactamase activity, which is aligned with current microbiology lab standards. This new method will enable the precise selection of effective β -lactam antibiotics (as opposed to defaulting to drugs of last resort) faster than current methods while using simple steps and low-cost portable instrumentation. Image 1 • We demonstrate phenotypic detection of β-lactamase activity using paper SERS sensors and portable instrumentation. • We show discrimination of β -lactamases with different degrees of resistance in a single sample on a single sensor. • We demonstrate a simple synthesis method to expand the library of SERS-based β -lactamase reporters. • We accomplish β-lactamase discrimination in significantly less time than conventional microbiology. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. Dual-channel foldable microfluidic paper-based parallel enzymatic reaction systems for simultaneous visual colorimetric detecting acetylcholinesterase and α-glucosidase together with screening inhibitors.
- Author
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Xu, Jinju, Tong, Chaoying, Cao, Yuanxin, Qin, Ziyi, Liao, Chunhui, Chen, Yuxia, Shi, Shuyun, and Guo, Ying
- Subjects
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ENZYME inhibitors , *GLYCOSIDASE inhibitors , *ACETYLCHOLINESTERASE , *ALPHA-glucosidases , *VITAMIN C , *CHEMICAL synthesis , *DRUG development , *STANDARD deviations , *NATURAL products - Abstract
On-site multi-enzymes detection and inhibitors screening are still challenging and particularly urgent. Here, dual-channel foldable microfluidic paper (μPAD)-based parallel enzymatic reaction systems were fabricated for simultaneous visual colorimetric detecting acetylcholinesterase (AChE) and α-glucosidase (α-Glu) together with screening inhibitors. μPAD composing of two layers with dual channels was designed and prepared facilely by a permanent marker. AChE and α-Glu catalyze pre-loaded substrates into products (thiocholine (TCh), ascorbic acid (AA)) on the 1st layer. Parallelly, oxidase-like MnO 2 nanosheets oxidize pre-dropped colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) on the 2nd layer. After simple folding μPAD, TCh and AA can reduce oxTMB to TMB, resulting in color fading. Obviously, bioenzyme and nanozyme reactions under different pH can simultaneously occur on the μPAD. Furthermore, colorimetric results can be easily captured and on-site quantitatively analyzed by smartphone. As a result, a convenient, efficient, sensitive, and specific platform has been constructed for simultaneous detecting AChE and α-Glu in human serum samples (recoveries, 92.1–105.0%; relative standard deviations, < 3.6%), and screening inhibitors from synthesized compounds and natural products. The developed platform provides constructive insights for exploitation of visual detecting strategies for simultaneous sensing muti-targets for point-of-care testing of disease and development of drugs. [Display omitted] • Visual colorimetric detection of AChE and α-Glu and screening of inhibitors. • Dual-channel foldable μ PAD for on-site simultaneous visual detection. • Parallel enzymatic reaction strategy matches different working pH. • The proposed platform had facile, portable, and visual advantages in POCT. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Estimation of Fibre Orientation in Paper Products by an Image Analysis On-line System.
- Author
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Erdman, Aleksandra, Grzyb, Tomasz, Kulpinski, Piotr, Lazarek, Jagoda, Lis, Stefan, Olejnik, Konrad, Reczulski, Mariusz, Szczepaniak, Piotr S., and Wysocka-Robak, Agnieszka
- Subjects
ANISOTROPY ,PHOSPHORS ,CHEMICAL synthesis ,IMAGE analysis ,PHYSIOLOGICAL control systems ,HOUGH transforms - Abstract
A paper web produced under industrial conditions always exhibits an anisotropy in its mechanical properties measured in the machine and cross directions. Proper and fast information about current paper anisotropy would significantly increase the efficiency of web quality control systems and allow to produce paper with greater precision. The main objective of the work presented was to determine the possibility of measurement of paper anisotropy. The method proposed is based on the image analysis of the orientation and location of special markers -- luminescent fibres -- which were introduced to the structure of the paper. Studies have shown that the method of image analysis provides a detection of fibres with a satisfactory level of efficiency, thus allowing accurate examination of the anisotropy of the paper samples analysed. On the basis of experiments, it was also found that the method of image analysis proposed allows to detect fibres with an accuracy appropriate for the problem under consideration. The invention presented has already been registered in a Patent Office as submission no. P.411294. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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- View/download PDF
8. Aging characterization of electrical insulation papers impregnated with synthetic ester and mineral oil: Correlations between mechanical properties, depolymerization and some chemical markers.
- Author
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Fernandez, Oscar H. Arroyo, Fofana, Issouf, Jalbert, Jocelyn, Gagnon, Sylvie, Rodriguez-Celis, Esperanza, Duchesne, Steve, and Ryadi, Mohamed
- Subjects
ELECTRIC insulators & insulation ,ESTERS ,CHEMICAL synthesis ,MINERAL oils ,DEPOLYMERIZATION ,MECHANICAL behavior of materials ,THERMAL analysis - Abstract
This article presents a comparative study of two types of transformer solid insulation: standard Kraft and thermally upgraded Kraft papers. The paper samples were impregnated with two different fluids, namely a synthetic dielectric ester fluid, Midel 7131, and a synthesized mineral oil, Luminol Tri. The impregnated papers were submitted to, accelerated aging at 150°C, temperature higher than the temperatures found inside transformers, for extended periods. The results show that for the first hours of aging, the cellulose depolymerization was similar for all the four studied cases. At a specific point, the paper samples aged in the ester fluid exhibited a lower depolymerization exceeding the 8000 hours of aging without reaching the levelling-off degree of polymerization (LODP). A similar trend was observed through the decrease of mechanical properties of papers in the ester-based oil. However, the difference in performance of both fluids was amplified due to the temperature used; at lower temperatures the difference should be smaller. Additionally, a relationship between the degree of polymerization and the mechanical properties accessed by the tensile testing was obtained regardless of the type of paper or oil. The total acidity in the ester fluid was higher than in mineral oil. Methanol, a chemical marker that is closely linked to the rupture of 1,4-ß-glycosidic bonds of cellulose, showed a partial sensitivity to the cellulose aging in the ester fluid. Furan (C4H4O) content was monitored during the aging and its concentration was found to be sensitive to the depolymerization along with the decrease in the mechanical properties of cellulose papers regardless of the type of paper. More importantly, its concentration was found to be dependent on the type of oil. More investigations are needed to further confirm the importance of furan as an indirect indicator of the mechanical performance along with its correlation with the depolymerization of paper aged in ester fluids. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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9. Accelerated nucleophilic substitution reactions of dansyl chloride with aniline under ambient conditions via dual-tip reactive paper spray
- Author
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Thanit Praneenararat, Hairul Anuar Tajuddin, Monrawat Rauytanapanit, Norfatirah Muhamad Sarih, Zanariah Abdullah, Simon Maher, Cedric Boisdon, B Bastani, David Romero-Perez, and Abraham K. Badu-Tawiah
- Subjects
Materials science ,Science ,Inorganic chemistry ,02 engineering and technology ,Mass spectrometry ,01 natural sciences ,Article ,chemistry.chemical_compound ,Aniline ,Nucleophilic substitution ,Chemical synthesis ,Acetonitrile ,Multidisciplinary ,010401 analytical chemistry ,Dansyl chloride ,Substrate (chemistry) ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Yield (chemistry) ,Reagent ,Medicine ,0210 nano-technology ,Analytical chemistry - Abstract
Paper spray ionization (PSI) mass spectrometry (MS) is an emerging tool for ambient reaction monitoring via microdroplet reaction acceleration. PSI-MS was used to accelerate and monitor the time course of the reaction of dansyl chloride with aniline, in acetonitrile, to produce dansyl aniline. Three distinct PSI arrangements were explored in this study representing alternative approaches for sample loading and interaction; conventional single tip as well as two novel setups, a dual-tip and a co-axial arrangement were designed so as to limit any on-paper interaction between reagents. The effect on product abundance was investigated using these different paper configurations as it relates to the time course and distance of microdroplet travel. It was observed that product yield increases at a given distance and then decreases thereafter for all PSI configurations. The fluorescent property of the product (dansyl aniline) was used to visually inspect the reaction progress on the paper substrate during the spraying process. Amongst the variety of sample loading methods the novel dual-tip arrangement showed an increased product yield and microdroplet density, whilst avoiding any on-paper interaction between the reagents.
- Published
- 2020
10. Novel luminescent paper based calix[4]arene chelation enhanced fluorescence- photoinduced electron transfer probe for Mn2+, Cr3+ and F-.
- Author
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Sutariya, Pinkesh G., Soni, Heni, Gandhi, Sahaj A., and Pandya, Alok
- Subjects
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ANTHRAQUINONES , *AROMATIC compounds , *CHEMICAL synthesis , *CHELATION , *MANGANESE , *CHROMIUM - Abstract
Abstract A novel structurally simple calix[4]arene attached 1-aminoanthraquinone associated lower rim calix[4]arene conjugate was synthesized and has been used as turn on/off/on fluorescence probe for Mn2+, Cr3+ and F-. This chelation enhanced fluorescence - photoinduced electron transfer (CHEF-PET) based TAAC probe has been applied for its analytical application in real samples such as Mn2+ from blood serum, Cr3+ and F- from industrial effluent with 94–99% recovery. The limit of detection of this sensor is found to be 11 nM for Mn2+, 4 nM for Cr3+ and 19 nM for F- with the concentration range of 0–120 nM. Further, we report an easy-to-use, low cost and disposable paper-based sensing device for rapid chemical screening of Mn2+, Cr3+ and F-. The device comprises fluorescent sensing probes embedded into a nitrocellulose matrix where the resonance energy transfer phenomenon seems to be the sensing mechanism. It opens up new opportunities for simple and fast screening in remote settings where sophisticated instrumentation is not always available. The MOPAC-2016 software package has been used to optimize the TAAC using PM7 well established method and calculates the HOMO-LUMO energy band gap for structure TAAC and TAAC with Mn2+, Cr3+ and F- ion based structures. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]
- Published
- 2019
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11. A paper-based, cell-free biosensor system for the detection of heavy metals and date rape drugs.
- Author
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Gräwe, Alexander, Dreyer, Anna, Vornholt, Tobias, Barteczko, Ursela, Buchholz, Luzia, Drews, Gila, Ho, Uyen Linh, Jackowski, Marta Eva, Kracht, Melissa, Lüders, Janina, Bleckwehl, Tore, Rositzka, Lukas, Ruwe, Matthias, Wittchen, Manuel, Lutter, Petra, Müller, Kristian, and Kalinowski, Jörn
- Subjects
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BIOSENSORS , *ANALYSIS of heavy metals , *METAL detectors , *DATE rape drugs , *HAZARDOUS substances - Abstract
Biosensors have emerged as a valuable tool with high specificity and sensitivity for fast and reliable detection of hazardous substances in drinking water. Numerous substances have been addressed using synthetic biology approaches. However, many proposed biosensors are based on living, genetically modified organisms and are therefore limited in shelf life, usability and biosafety. We addressed these issues by the construction of an extensible, cell-free biosensor. Storage is possible through freeze drying on paper. Following the addition of an aqueous sample, a highly efficient cell-free protein synthesis (CFPS) reaction is initiated. Specific allosteric transcription factors modulate the expression of ‘superfolder’ green fluorescent protein (sfGFP) depending on the presence of the substance of interest. The resulting fluorescence intensities are analyzed with a conventional smartphone accompanied by simple and cheap light filters. An ordinary differential equitation (ODE) model of the biosensors was developed, which enabled prediction and optimization of performance. With an optimized cell-free biosensor based on the Shigella flexneri MerR transcriptional activator, detection of 6 μg/L Hg(II) ions in water was achieved. Furthermore, a completely new biosensor for the detection of gamma-hydroxybutyrate (GHB), a substance used as date-rape drug, was established by employing the naturally occurring transcriptional repressor BlcR from Agrobacterium tumefaciens. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
12. Ni-loaded (Ce,Zr)O2–δ-dispersed paper-structured catalyst for dry reforming of methane.
- Author
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Nguyen, T.G.H., Tran, D.L., Sakamoto, M., Uchida, T., Sasaki, K., To, T.D., Doan, D.C.T., Dang, M.C., and Shiratori, Y.
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METHANE , *CATALYSTS , *OXIDATION , *CATALYTIC activity , *CHEMICAL reactions , *CHEMICAL synthesis - Abstract
A paper-structured catalyst (PSC) for biogas reforming was prepared with the aim of improving coking tolerance. During the paper-making process using inorganic fibers, Ni-loaded (Ce,Zr)O 2–δ particles were synthesized via co-precipitation and subsequent chemical reduction (on-paper synthesis). The effects of the CeO 2 /ZrO 2 weight ratio during preparation and the Ni loading amount on the catalytic activity for dry reforming of CH 4 were investigated at 750 °C. A Ni loading of 6 wt% with CeO 2 /ZrO 2 ≥ 1 led to stable CH 4 conversion of 85% without coking under a gas hourly space velocity of 3800 h −1 . The oxygen storage capacity of the (Ce,Zr)O 2–δ particles dispersed in the inorganic fiber network may contribute to the oxidation of carbonaceous species deposited on the catalyst surface. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
13. TiO2–B nanofibrils reinforced graphene paper for multifunctional flexible electrode.
- Author
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Li, Meng, Yang, Yong, Guang Choo, Eugene Shi, Tang, Xiaosheng, Sun, Kuan, Chen, Yu, and Xue, Junmin
- Subjects
- *
TITANIUM dioxide , *GRAPHENE , *CHEMICAL synthesis , *THERMOELECTRICITY , *ELECTROCHEMICAL analysis - Abstract
Utilizing graphene-based hybrid papers or films as multifunctional electrodes has become the focus of clean energy devices due to the beneficial combination of their excellent electrical properties and multiple functions. However, limited attention has been paid to such hybrid papers with both outstanding mechanical and electrochemical properties. Recently, we fabricate rationally designed TiO 2 -B nanofibrils reinforced graphene paper, which can achieve high mechanical strength (88.5 MPa) without sacrificing their electrochemical properties. They further deliver capacities of 231 mAh g −1 (408.9 mAh cm −3 ) for Li-ion electrode and 201 mAh g −1 (355.8 mAh cm −3 ) for Na-ion electrode respectively at the same current density of 33.5 mA g −1 . The outstanding mechanical stability of as-prepared hybrid electrode is demonstrated with a prototype of a bendable Li-ion capacitor. Besides, the as-prepared electrodes also reveal great potential to serve as light weight and ultrathin electromagnetic interference shielding materials. Single layer of hybrid paper exhibits a shielding effectiveness of over 10 dB (corresponding ∼90% shielding). These results prove that TiO 2 -B nanofibrils reinforced graphene paper can serve as a multifunctional flexible electrode for diverse applications. Moreover, this work also demonstrates a novel strategy on how to enhance mechanical properties for those flexible electrodes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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14. Fenton-like degradation of Methylene Blue using paper mill sludge-derived magnetically separable heterogeneous catalyst: Characterization and mechanism.
- Author
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Zhou, Guoqiang, Chen, Ziwen, Fang, Fei, He, Yuefeng, Sun, Haili, and Shi, Huixiang
- Subjects
- *
METHYLENE blue , *MAGNETIC separation , *HETEROGENEOUS catalysts , *PAPER mill waste , *CHEMICAL decomposition , *CHEMICAL synthesis - Abstract
For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst (PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue (MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover, leaching tests indicated that the leached iron is negligible (< 0.5 mg/L). This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
15. Production of recycled cellulose fibers from waste paper via ultrasonic wave processing.
- Author
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Guo, Xiuyan, Jiang, Zhengwu, Li, Haoxin, and Li, Wenting
- Subjects
CELLULOSE fibers ,TEXTILE industry ,PAPER recycling ,ULTRASONIC waves ,PLANT products ,CHEMICAL synthesis ,BIOPOLYMERS - Abstract
ABSTRACT Recycling waste paper can be considered as a means to displace the use of natural cellulose fibers applied in building materials, because it is composed mostly of cellulose. The water absorption and special surface area of cellulose fibers are the key properties for their use in building materials. The objective of this article was to study the production of recycled cellulose fibers from waste paper using ultrasonic wave processing. The physical and chemical properties of recycled cellulose fibers, such as water absorption, specific surface area and pore characteristics, etc., were investigated with various testing methods. The results indicated that the ultrasonic cavitation effect was feasible for the preparation of the secondary fibers. When the ultrasonic treatment time lasted for 10 min, the water absorptions of both newsprint fibers and kraft fibers increased significantly and reached the highest values of 12.5 g/g and 11.2 g/g, respectively, which were nearly two times than that of fibers without ultrasonic treatment. With a pretreatment of 20 min, the average length and fineness of recycled cellulose fibers decreased by 4% and 25%, respectively, and the length-diameter ratio of the recycled cellulose fibers was 1.28 times than that of the untreated fibers, which greatly increased the special surface area of the recycled cellulose fibers. This work also determined that NaOH was useful to improve the physical properties of the recycled cellulose fibers. Because the recycled cellulose fibers after processing, fulfilled several technical indexes, they can be considered as a filling material for used in cement-based materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41962. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
16. Hydroxyapatite Nanowires@Metal-Organic Framework Core/Shell Nanofibers: Templated Synthesis, Peroxidase-Like Activity, and Derived Flexible Recyclable Test Paper.
- Author
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Chen, Fei‐Fei, Zhu, Ying‐Jie, Xiong, Zhi‐Chao, and Sun, Tuan‐Wei
- Subjects
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CHEMICAL synthesis , *HYDROXYAPATITE , *NANOFIBERS , *NANOWIRES , *CHELATION , *PEROXIDASE - Abstract
The templated synthesis of hydroxyapatite (HAP) nanowires@metal-organic framework (MOF) core/shell nanofibers (named HAP@MIL-100(Fe) nanofibers) is demonstrated. The ultralong hydroxyapatite nanowires are adopted as a hard template for the nucleation and growth of MIL-100(Fe) (a typical MOF) through the layer-by-layer method. The Coulombic and chelation interactions between Ca2+ ions on the surface of the HAP nanowires and the COO− organic linkers of MIL-100(Fe) play key roles in the formation process. The as-prepared, water-stable HAP@MIL-100(Fe) nanofibers exhibit peroxidase-like activity toward the oxidation of different peroxidase substrates in the presence of H2O2, accompanied by a clear color change of the solution. Furthermore, a flexible, recyclable HAP@MIL-100(Fe) test paper is prepared successfully by using HAP@MIL-100(Fe) nanofibers as building blocks. A simple, low-cost, and sensitive colorimetric method for the detection of H2O2 and glucose is established based on the as-prepared, flexible, recyclable HAP@MIL-100(Fe) test paper. More importantly, the HAP@MIL-100(Fe) test paper can be recovered easily for reuse by simply dipping in absolute ethanol for just 30 min, thus showing excellent recyclability. With its combination of advantages such as easy transportation, easy storage and use, rapid recyclability, light weight, and high flexibility, this HAP@MIL-100(Fe) test paper is promising for wide applications in various fields. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Synthesis and Developing Properties of Functional Phenolic Polymers for Ecofriendly Thermal Papers.
- Author
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Kang-Hoon Choi, Hyun-Jin Kwon, and Byeong-Kwan An
- Subjects
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PHENOLS , *FORMALDEHYDE , *CHEMICAL synthesis , *CHEMICAL reactions , *POLYMERS - Abstract
Owing to the multiple potential health risks caused by exposure to BPA and the strengthened regulation of BPA-containing thermal papers, much concern has been raised recently regarding a BPA-type color developer in thermal papers. However, few efforts have so far been focused on the development of safer alternative materials to BPA. In this study, we examined the use of polymeric materials as a safer replacement for BPA in thermal papers. For this objective, a series of phenolic polymers, phenol-formaldehyde novolac and resole (PF-N and PF-R) and BPA-formaldehyde novolac and resole (BPAF-N and BPAF-R), were prepared. Among these polymers, a BPAF-N-type polymer was determined to be the most appropriate candidate for a developer material in thermal papers. Through printing tests of the prepared thermal papers, it was found that BPAF-N_8 polymer has a high static sensitivity and dark contrast of thermal papers similar to those of BPA, whereas the BPAF-N_16 and BPAF-N_30 polymers have lower static sensitivities than BPFA-N_8 and BPA. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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18. Chemical Synthesis Accelerated by Paper Spray: The Haloform Reaction
- Author
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Shannon A. Raab, R. Graham Cooks, Ryan M. Bain, and Christopher J. Pulliam
- Subjects
Chemistry ,010401 analytical chemistry ,Analytical chemistry ,General Chemistry ,Haloform reaction ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,Chemical synthesis ,0104 chemical sciences ,Education ,Solvent ,Qualitative analysis ,Ionization ,Spectral data ,Droplet size - Abstract
In this laboratory, students perform a synthetic reaction in two ways: (i) by traditional bulk-phase reaction and (ii) in the course of reactive paper spray ionization. Mass spectrometry (MS) is used both as an analytical method and a means of accelerating organic syntheses. The main focus of this laboratory exercise is that the same ionization source can be operated to perform chemical analysis or to accelerate synthesis. More specifically, students explore the effect on reaction progress of operating in one of two modes of paper spray ionization. The modes relate to droplet size that changes as the solvent is depleted from the paper over time. The online mass spectral data for the two modes allow students to see the differences that small changes to spray conditions can have on the MS of a reaction mixture, allowing transition from traditional analysis to accelerated chemical synthesis by simply allowing the paper to partially dry. Chemical analysis and accelerated synthesis can be performed sequentiall...
- Published
- 2015
- Full Text
- View/download PDF
19. Molecular Weight of Amphoteric Polyacrylamide: How it is Influenced by the Variables in Synthesis, and its Impacts on the Dry Strength of Paper Sheets.
- Author
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Yangyang Zhu, Er-suo Jin, Fang Yang, Xiangyu Li, Wenyuan Zhu, Chunli Yao, and Junlong Song
- Subjects
- *
MOLECULAR weights , *POLYACRYLAMIDE , *CHEMICAL synthesis , *DRY strength of paper , *FLOCCULATION , *FILTERS & filtration , *MONOMERS , *ISOELECTRIC point - Abstract
Amphoteric polyacrylamide (AmPAM) is a linear water-soluble polymer that has been applied in papermaking as an agent for flocculation, retention, filtration, and dry-strength improvement. However, AmPAM with different ranges of molecular weight (MW) have different properties in these processes. In this study, a series of AmPAMs were constructed with an anionic monomer, itaconic acid (IA), a cationic monomer, methacryloxyethyl-trimethyl ammonium chloride (DMC), and a main backbone of acrylamide (AM). Four factors influencing free radical polymerization, i.e., reaction temperature, pH, initiator load, and the concentration of monomers, were systematically investigated via an orthogonal test to determine their effects on the MW of AmPAM. Spectroscopy and isoelectric point assays were used to characterize the structure of the produced AmPAM, and the MW was assessed by calculating the viscosity. The reaction temperature had the greatest influence on the MW of AmPAM, followed by the solution pH and the initiator load. To determine the dry strength of papersheets containing AmPAM, the breaking length of handsheets was assessed after adding 0.5% AmPAM (based on fiber) with different MWs. The maximum value, 4.05 km, was 15.0% higher than the control and was obtained using AmPAM with a MW of 330 kDa. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. SYNLETT Best Paper Award 2017: Synthesis of Tetraarylmethanes by the Triflic Acid-Promoted Formal Cross-Dehydrogenative Coupling of Triarylmethanes with Arenes.
- Subjects
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CHEMICAL synthesis , *DEHYDROGENATION , *TRIARYLMETHANE dyes - Abstract
Background. Thieme Chemistry and the Editors of SYNTHESIS and SYNLETT present the 'SYNTHESIS/ SYNLETT Best Paper Awards'. These annual awards honor the authors of the best original research papers in each of the journals, considering their immediate impact on the field of chemical synthesis. Cathleen Crudden, Masakazu Nambo and their co-workers are the recipients of the SYNLETT Best Paper Award 2017. The work was a collaboration between Nagoya University in Japan and Queen's University in Canada. The authors are recognized for their work on the synthesis of tetraarylmethanes through a formal cross-dehydrogenative coupling of triarylmethanes with arenes, promoted by triflic acid. Benjamin List, Editor-in-Chief of SYNLETT, commented:"Nambo, Yim, Fowler, and Crudden have developed an elegant synthesis of tetraarylmethanes that involves an acid-catalyzed oxidative coupling of an arene with triarylmethanes, which became readily accessible in previous studies by the authors. The reaction proceeds via trityl-type cations and enables the formation of fascinating products, in which four different arenes are connected via a single stereogenic carbon atom." SYNFORM spoke with Masakazu Nambo and Cathleen Crudden, who were happy to share some background information regarding the prize-winning paper as well as current research activities ongoing in their groups. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
21. Understanding ethanol versus methanol formation from insulating paper in power transformers.
- Author
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Rodriguez-Celis, E., Duchesne, S., Jalbert, J., and Ryadi, M.
- Subjects
ETHANOL ,METHANOL ,CHEMICAL synthesis ,CELLULOSE insulation ,DEGREE of polymerization ,CELLULOSE ,BIODEGRADATION ,PYROLYSIS gas chromatography - Abstract
The life of an electrical transformer is mainly determined by that of its cellulosic solid insulation. The analysis of the chemical markers of cellulose degradation dissolved in oil is a simple and economical way to indirectly characterize the insulating paper. Methanol, a marker that is intimately linked to the rupturing of 1,4-β-glycosidic bonds of cellulose, has been observed together with ethanol during laboratory ageing experiments. Regardless of the simulated ageing conditions (temperature, humidity, air), the ratio of methanol to ethanol concentration is always higher than one (unity). However, in approximately 10 % of transformer oil samples, the ethanol generation is higher than that of methanol. In this study, thermal degradation by pyrolysis is coupled with gas chromatography/mass spectrometry to assess the volatile by-products generated at high temperatures with emphasis on methanol/ethanol generation. Some cellulose model compounds were also pyrolyzed and thermally aged in oil. The results showed that the generation of ethanol from paper pyrolysis is always smaller than for methanol, but it only occurs at temperatures higher than 300 °C. However, thermal ageing of levoglucosan in oil generates a massive amount of ethanol compared to methanol regardless of the conditions (temperature, humidity, air, nitrogen, acidity). The hypothesis that ethanol is a by-product of cellulose degradation through levoglucosan as an intermediary in power transformers is proposed. The presence of ethanol during transformer oil analysis is of high interest because it can be related to a thermal fault or hot spot within the solid insulation. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
22. Linked PDF of Table of Contents.
- Subjects
- *
ADDITION reactions , *PAPER chemicals , *CHEMICAL synthesis , *ACID catalysts , *NUCLEOSIDE synthesis - Published
- 2024
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23. Electronic Laboratory Notebook Snapshots for paper entitled Open Source Drug Discovery - Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles
- Author
-
Todd, Matthew H
- Subjects
electronic laboratory notebooks ,malaria ,open data ,chemical synthesis ,drug discovery ,organic chemistry - Abstract
The files are zipped snapshots of the electronic laboratory notebooks (ELNs) used by the Open Source Malaria (OSM) consortium that are relevant to the paper "Open Source Drug Discovery - Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles". The current "live" versions of the ELNs, and ELNs relevant to other parts of OSM, may be found at http://malaria.ourexperiment.org/. Many scientists contributed to these resources, and their names may be found within the ELNs and in the paper authorship list. Australian Research Council and the Medicines for Malaria Venture. There were numerous project inputs (cash and in-kind) from other sources, and these are listed exhaustively in the acknowledgements section of the relevant paper.
- Published
- 2015
24. 56.2: Invited Paper: Novel Bistable Liquid Crystal Materials for AR/VR Technology, Vehicle and Flexible Display.
- Author
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Lapanik, Valeri, Lugovski, Anatoly, and Timofeev, Sergei
- Subjects
LIQUID crystals ,FLEXIBLE display systems ,NEMATIC liquid crystals ,LIQUID crystal displays ,SMECTIC liquid crystals ,VISCOELASTIC materials ,CHEMICAL synthesis - Abstract
The object of study is chiral‐nematic and smectic A liquid crystals. The aim of the work is to develop new bistable materials with improved physico‐chemical and electro‐optical properties for various applications. Chiral liquid‐crystalline compounds and compounds characterized by the presence of the smectic A phase over a wide temperature range were synthesized during the studies. The influence of the viscoelastic properties of liquid crystals, the anchoring energy of the alignment material, and the helical twisting power of chiral dopants on the memory effect in chiral‐nematic liquid crystals was investigated. In order to clarify the possible mechanism of bistability in highly twisted nematics, we performed a numerical simulation of the reorientation of liquid crystal molecules in an electric field. It was also necessary to find out which parameters of the liquid crystal material have the greatest effect on the bistability. Based on the synthesized smectic compounds, mixtures with different values of optical anisotropy and viscosity were developed. The influence of the compounds structure (bridge fragments, polar groups, alkyl chains) on mesomorphic and basic physico‐chemical characteristics was determined. Electrically and electrochemically stable ion dopants were also synthesized with a number of organic cations and organic/inorganic anions. The composition of mixtures has been optimized for long‐term operation, especially in the upper operating temperature range. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
25. Cronin Group PLC - CRON Publication of Scientific Paper
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Chemical synthesis ,General interest ,News, opinion and commentary - Abstract
London: Cronin Group PLC has issued the following news release: Cronin Group Plc ('Cronin Group') Publication of Scientific Paper Publication in PNAS reports results using methodologies covered by Cronin Group's [...]
- Published
- 2018
26. Paper templated synthesis of nanostructured Cu–ZnO and its enhanced photocatalytic activity under sunlight.
- Author
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Kale, Gajanan, Arbuj, Sudhir, Kawade, Ujjwala, Kadam, Sunil, Nikam, Latesh, and Kale, Bharat
- Subjects
ZINC oxide ,NANOSTRUCTURED materials ,CHEMICAL synthesis ,COPPER ,PHOTOCATALYSIS - Abstract
Cu-doped zinc oxide (Cu–ZnO) nanostructure was prepared using Whatman filter paper as a template by combustion method. For the synthesis of porous Cu–ZnO nanostructures the stoichiometric amount of precursors were impregnated in the filter papers and processed, thermally. The formation of wurtzite phase having crystallite size in the range of 20–24 nm was confirmed by X-ray diffraction (XRD) analysis. The morphological study by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) shows size of nanoparticles in the range of 25–50 nm. The optical study shows red shift i.e. extended absorbance in the visible region due to Cu doping. The photoluminescence study of Cu–ZnO results quenching in the photoluminescence peak as effect of Cu doping in ZnO lattice. Considering the extended band gap in the visible region of as synthesized Cu–ZnO, the photocatalytic dye degradation activity of methylene blue (MB) was executed in presence of sunlight irradiation. The effect of salt concentration and PH on dye degradation activity also studied. The highest photocatalytic activity was observed for Cu–ZnO with 4% doping as compared with other Cu–ZnO and ZnO nanostructure. The photocatalytic performance of Cu–ZnO shows complete degradation of MB dye within 30 min for 4% Cu–ZnO nanostructure. The photocatalytic activity obtained is much higher as compare to earlier reports. The synthesis of Cu doped ZnO by paper templated method and its photocatalytic activity is hitherto unattempted. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
27. Review: nanoparticles and nanostructured materials in papermaking.
- Author
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Samyn, Pieter, Barhoum, Ahmed, Öhlund, Thomas, and Dufresne, Alain
- Subjects
NANOPARTICLES ,NANOSTRUCTURED materials ,PAPERMAKING ,CHEMICAL synthesis ,CELLULOSE - Abstract
The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
28. Reports on Chemical Education from Purdue University Provide New Insights (Chemical Synthesis Accelerated by Paper Spray: The Haloform Reaction)
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Education -- Indiana ,Chemical synthesis ,Education ,News, opinion and commentary ,Purdue University - Abstract
2016 MAR 16 (VerticalNews) -- By a News Reporter-Staff News Editor at Education Letter -- A new study on Chemical Education is now available. According to news reporting out of [...]
- Published
- 2016
29. SYNTHESIS Best Paper Award 2015: Harnessing the Intrinsic Reactivity within the Aplysinopsin Series for the Synthesis of Intricate Dimers: Natural from Start to Finish.
- Subjects
TECHNICAL reports ,CHEMICAL synthesis ,INTERDISCIPLINARY research ,ORGANIC synthesis ,AWARDS - Abstract
An interview with professor of pharmacognosy and natural product chemistry Erwan Poupon and Laurent Evanno, Doctor of Philosophy (PhD) working on total synthesis, who were the winners of the 2015 SYNTHESIS Best Paper Award which recognizes authors of original papers in the field of synthesis, is presented. Topics discussed include the aspects of their research paper, the application of the multidisciplinary projects which focuses on natural substances, and the role of organic synthesis.
- Published
- 2016
- Full Text
- View/download PDF
30. Nanomaterials in Proton Exchange Membrane Fuel Cells
- Author
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Zhang, Yufeng, Xue, Rui, Yuan, Weijian, Liu, Xiaowei, Li, Fan, editor, Bashir, Sajid, editor, and Liu, Jingbo Louise, editor
- Published
- 2018
- Full Text
- View/download PDF
31. SYNLETT Best Paper Award 2017: Synthesis of Tetraarylmethanes by the Triflic Acid-Promoted Formal Cross-Dehydrogenative Coupling of Triarylmethanes with Arenes.
- Subjects
CHEMICAL synthesis ,NAGOYA University (Japan) ,OXIDATIVE coupling ,CHEMICALS ,METHANE ,SULFONES ,PHOSPHORUS ,BIOLOGISTS - Published
- 2018
- Full Text
- View/download PDF
32. SYNTHESIS Best Paper Award 2017: Asymmetric Synthesis of 2,3,4-Trisubstituted Piperidines.
- Author
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Kanger, Tõnis
- Subjects
COLLEGE teachers ,CHEMICAL synthesis ,PIPERIDINE ,PHARMACEUTICAL chemistry - Published
- 2018
- Full Text
- View/download PDF
33. Inside Back Cover: Hydroxyapatite Nanowires@Metal-Organic Framework Core/Shell Nanofibers: Templated Synthesis, Peroxidase-Like Activity, and Derived Flexible Recyclable Test Paper (Chem. Eur. J. 14/2017).
- Author
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Chen, Fei‐Fei, Zhu, Ying‐Jie, Xiong, Zhi‐Chao, and Sun, Tuan‐Wei
- Subjects
- *
HYDROXYAPATITE , *CHEMICAL synthesis , *PEROXIDASE - Abstract
The templated synthesis of ultralong hydroxyapatite nanowires@metal–organic framework core/shell (HAP@MIL‐100(Fe)) nanofibers has been demonstrated herein. The HAP@MIL‐100(Fe) nanofibers exhibited peroxidase‐like activity towards the oxidation of different peroxidase substrates in the presence of H2O2 accompanying with the clear color change of the solution. A new kind of flexible test paper was prepared by using HAP@MIL‐100(Fe) nanofibers as building blocks, which can be used for the detection of H2O2 and glucose, and it can be easily recovered, exhibiting excellent recyclability and promising applications in various fields. More information can be found in the Full Paper by Y.‐J. Zhu and Z.‐C. Xiong et al. on page 3328 ff. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
34. Preparation and Characterization of Cellulose-CaCO3 Composites by an Eco-Friendly Microwave-assisted Route in a Mixed Solution of Ionic Liquid and Ethylene Glycol.
- Author
-
Xu-Feng Cheng, Hua Qian, Shan-Wei Zhang, Zhan-Shuo Zhang, Yuan He, and Ming-Guo Ma
- Subjects
CELLULOSE ,CALCIUM acetate ,SOLUTION (Chemistry) ,IONIC liquids ,ETHYLENE glycol ,CHEMICAL synthesis ,PAPER industry - Abstract
The purpose of this study was to investigate a popular reinforcing agent in the papermaking industry through a quick, environmentally friendly, microwave-assisted method. The preparation and characterization of cellulose-CaCO
3 composites through this route, in a mixed solution of an ionic liquid and ethylene glycol, can occur within a 10-min timeframe. The chemical compounds, calcium acetate and sodium carbonate, were used as reactants for the as-obtained CaCO3 crystals. A NaOH-urea aqueous solution was used to treat the cellulose and prepare cellulose- CaCO3 composites. It was discovered that the addition of ionic liquids favors the preparation of cellulose-CaCO3 composites. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
35. Pharmaceuticals Best Paper Award 2015.
- Author
-
Vanden Eynde, Jean Jacques
- Subjects
- *
CHEMICAL synthesis , *TRASTUZUMAB , *BREAST tumors , *THERAPEUTICS - Abstract
The article discusses the Pharmaceuticals Best Paper Award 2015 given to publications including synthesis and biological evaluation about a potent (R)-alpha-bis-lipoyl derivative, radiolabeled trastuzumab imaging for metastatic breast tumors and orthotopic and ways of cell-specific evaluation.
- Published
- 2015
- Full Text
- View/download PDF
36. Reviews and syntheses: Greenhouse gas emissions in natural and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further studies.
- Author
-
Kim, D.-G., Thomas, A. D., Pelster, D., Rosenstock, T. S., and Sanz-Cobena, A.
- Subjects
GREENHOUSE gases ,CHEMICAL synthesis ,FARMS ,EMISSIONS (Air pollution) ,SOIL pollution - Abstract
This paper summarizes currently available data on greenhouse gas (GHG) emissions from African natural and agricultural lands, outlines the knowledge gaps and suggests future directions and strategies for GHG emission studies. GHG emission data were collected from 73 studies conducted in 22 countries in sub-Saharan Africa (SSA). Soil GHG emissions from African natural terrestrial systems ranged from 3.3 to 57.0 Mg carbon dioxide (CO
2 ) ha-1 yr-1 , -4.8 to 3.5 kg methane (CH4 ) ha-1 yr-1 and -0.1 to 13.7 kg nitrous oxide (N2 O) ha-1 yr-1 . Soil physical and chemical properties, rewetting, vegetation type, forest management and land-use changes were all found to be important factors affecting soil GHG emissions. Greenhouse gas emissions from African aquatic systems ranged from 5.7 to 232.0 Mg CO2 ha-1 yr-1 , -26.3 to 2741.9 kg CH4 ha-1 yr-1 and 0.2 to 3.5 kg N2 O ha-1 yr-1 and were strongly affected by discharge. Soil GHG emissions from African croplands ranged from 1.7 to 141.2 Mg CO2 ha-1 yr-1 ,-1 .3 to 66.7 kg CH4 ha-1 yr-1 and 0.05 to 112.0 kg N2 O ha-1 yr-1 and the N2 O emission factor (EF) ranged from 0.01 to 4.1%. Incorporation of crop residues or manure with inorganic fertilizers resulted in significant changes in GHG emissions but these were different for CO2 and N2 O. Soil GHG emissions in vegetable gardens ranged from 73.3 to 132.0 Mg CO2 ha-1 yr-1 and 53.4 to 177.6 kg N2 O ha-1 yr-1 and N2 O EFs ranged from 3 to 4%. Soil CO2 and N2 O emissions from agroforestry were 38.6 Mg CO2 ha-1 yr-1 and 0.2 to 26.7 kg N2 O ha-1 yr-1 , respectively. Improving fallow with nitrogen (N)-fixing trees increased CO2 and N2 O emissions compared to conventional croplands and type and quality of plant residue is likely to be an important control factor affecting N2 O emissions. Throughout agricultural lands, N2 O emissions slowly increased with N inputs below 150 kg N ha-1 yr-1 and increased exponentially with N application rates up to 300 kg N ha-1 yr-1 . The lowest yield-scaled N2 O emissions were reported with N application rates ranging between 100 and 150 kg N ha-1 . Overall, total CO2 equivalent (eq) emissions from African natural and agricultural lands were 56.9 ± 12.7 Pg CO2 eq yr-1 and natural and agricultural lands contributed 76.3 and 23.7%, respectively. Additional GHG emission measurements throughout Africa agricultural and natural lands are urgently required to reduce uncertainty on annual GHG emissions from the different land uses and identify major control factors and mitigation options on emissions. There is also a need to develop a common strategy for addressing this data gap that may involve identifying priorities for data acquisition, utilizing appropriate technologies, and establishing networks and collaboration. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
37. Telling it like it is.
- Author
-
Partridge, Matthew
- Subjects
FILTER paper ,CHEMICAL synthesis - Abstract
It might have been harderto complete, but produced a 70% reduction indeforestation-pollution-beans per article, althoughthe author was relabelled irritable-frowny-grumpdue to their impact on those around them. So instead ofstandard chemical names like diphenadione, weuse their environmental effect name; in this case,squirrel-murder-crystals. Lab•or•a•tol•o•gy How to temper the urge to make projects succeed at theexpense of sustainability?. [Extracted from the article]
- Published
- 2023
38. Homogeneous microwave-assisted carboxymethylation from totally chlorine free bleached olive tree pruning residues pulp
- Author
-
Omar Harzallah, Narjes Rjiba, Mohamed Hamdaoui, Chedly Boudokhane, and Imen Landolsi
- Subjects
Pulp (paper) ,technology, industry, and agriculture ,macromolecular substances ,General Chemistry ,engineering.material ,Chemical synthesis ,Solvent ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Yield (chemistry) ,Scientific method ,engineering ,Cellulose ,Fourier transform infrared spectroscopy ,Derivative (chemistry) - Abstract
This study deals with a new methodology for the production of carboxymethyl cellulose (CMC) from olive pruning residues, agricultural by-products. Cellulose was extracted by the soda?anthraquinone pulping process, and the pulp bleaching was performed using totally chlorine free (TCF) bleaching. Then, CMC microwave-assisted synthesis was performed in a homogeneous media, using DMA/LiCl as a cellulose solvent. A Box?Behnken design was applied in order to evaluate which parameters of the carboxymethylation process (viz. reaction time, reaction temperature, and amount of monochloroacetic acid) affect the degree of substitution and the yield of the synthesis reaction of this cellulose derivative. Optimized conditions to yield CMC were determined based on the desirability function approach. The prepared materials under synthesis using the optimal conditions were characterized using several analytical tools, i.e., FTIR, TGA, DSC and SEM. This cellulose derivative was successfully fabricated by a fast and efficient microwave-assisted method and thus would provide many opportunities for diverse applications.
- Published
- 2022
- Full Text
- View/download PDF
39. Language Models for Predicting Organic Synthesis Procedures.
- Author
-
Vaškevičius, Mantas and Kapočiūtė-Dzikienė, Jurgita
- Subjects
MACHINE learning ,LANGUAGE models ,TRANSFORMER models ,ORGANIC synthesis ,CHEMICAL synthesis - Abstract
Featured Application: Leveraging fine-tuned large language models, this study enhances the prediction of efficient chemical synthesis procedures, saving time and resources in laboratory workflows. The findings highlight the potential of tailored AI approaches in transforming organic synthesis through intelligent, data-driven methods. In optimizing organic chemical synthesis, researchers often face challenges in efficiently generating viable synthesis procedures that conserve time and resources in laboratory settings. This paper systematically analyzes multiple approaches to efficiently generate synthesis procedures for a wide variety of organic synthesis reactions, aiming to decrease time and resource consumption in laboratory work. We investigated the suitability of different sizes of BART, T5, FLAN-T5, molT5, and classic sequence-to-sequence transformer models for our text-to-text task and utilized a large dataset prepared specifically for the task. Experimental investigations demonstrated that a fine-tuned molT5-large model achieves a BLEU score of 47.75. The results demonstrate the capability of LLMs to predict chemical synthesis procedures involving 24 possible distinct actions, many of which include various parameters like solvents, reaction agents, temperature, duration, solvent ratios, and other specific parameters. Our findings show that only when the core reactants are used as input, the models learn to correctly predict what ancillary components need to be included in the resulting procedure. These results are valuable for AI researchers and chemists, suggesting that curated datasets and large language model fine-tuning techniques can be tailored for specific reaction classes and practical applications. This research contributes to the field by demonstrating how deep-learning-based methods can be customized to meet the specific requirements of chemical synthesis, leading to more intelligent and resource-efficient laboratory processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Raman Studies in Chemically Synthesized Nanocrystalline CuS Thin Films.
- Author
-
Gosavi, Narayani M., Wagh, T. R., Sali, K. R., and Gosavi, S. R.
- Subjects
SUBSTRATES (Materials science) ,THIN film deposition ,THIN films ,BAND gaps ,DIFFRACTION patterns - Abstract
This paper describes the chemical synthesis of nanocrystalline CuS thin films onto glass substrate at 40 ℃. The effect of the deposition time on the Raman spectroscopy results and physical properties was investigated. X-ray diffraction pattern showed the amorphous nature of CuS thin films deposited with deposition time of 20 min and transferred to orthorhombic crystal structure for CuS thin films with deposition time of 40 min. Raman modes observed at around 273 cm
– 1 and 475 cm– 1 in CuS thin films support the formation of covellite CuS phase. FESEM images taken from the surfaces of chemically deposited nanocrystalline CuS thin films shows the dense structure, smooth and relatively void-free surfaces and surface looks well adhered to the glass substrate. The optical band gap was estimated to be in the range between 2.05 eV and 2.15 eV depending on the deposition time. Finally, as a result of the analysis, we can say that the variation in deposition time can affect the structural properties of CuS thin films. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
41. Combined effect of nitrogen-doped carbon and NiCo2O4 for electrochemical water splitting.
- Author
-
Kubińska, Laura, Szkoda, Mariusz, Skorupska, Malgorzata, Grabowska, Patrycja, Gajewska, Marta, Lukaszewicz, Jerzy P., and Ilnicka, Anna
- Subjects
GREEN fuels ,HYBRID materials ,CHEMICAL synthesis ,HYDROGEN production ,CATALYTIC activity ,HYDROGEN evolution reactions ,OXYGEN evolution reactions - Abstract
Electrocatalytic water splitting for green hydrogen production necessitates effective electrocatalysts. Currently, commercial catalysts are primarily platinum-based. Therefore, finding catalysts with comparable catalytic activity but lower cost is essential. This paper describes spinel-structured catalysts containing nickel cobaltite NiCo
2 O4 , graphene, and additionally doped with heteroatoms. The structure and elemental composition of the obtained materials were analyzed by research methods such as TEM, SEM-EDX, XRD, XPS, and Raman spectroscopy. The electrochemical measurements showed that hybrid materials containing nickel cobaltite NiCo2 O4 doped with graphene are highly active catalysts in the hydrogen evolution reaction (Tafel slopes = 91 mV dec−1 , overpotential = 468 mV and onset potential = -339 mV), while in the oxygen evolution reaction (Tafel slopes = 51 mV dec−1 , overpotential = 1752 mV and onset potential = 370 mV), bare NiCo2 O4 without the addition of carbon has a worse activity (for HER: Tafel slopes = 120 mV dec−1 , overpotential - does not achieve and onset potential = -404 mV, for OER: Tafel slopes = 54 mV dec−1 , overpotential = 1796 mV and onset potential = 410 mV). In terms of stability, comparable results were obtained for each synthesized compound for both the HER and OER reactions. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
42. Chemical Synthesis of 6-Azido-6-Deoxy Derivatives of Phosphatidylinositol Containing Different Fatty Acid Chains.
- Author
-
Molla, Mosidur Rahaman, Gupta, Palak, Rohokale, Rajendra, and Guo, Zhongwu
- Subjects
AZIDO group ,CHEMICAL synthesis ,FATTY acids ,GLYCOSYLPHOSPHATIDYLINOSITOL ,INOSITOL - Abstract
This paper describes the synthesis of two 6-azido-6-deoxy derivatives of phosphatidylinositol (PI), which contained different fatty acid chains. These syntheses, starting from methyl α-d-glucopyranoside, employed multiple regioselective transformations with Ferrier rearrangement as one of the key steps. The PI derivatives contained different fatty acid chains in the lipids and an azido group in the inositol residue to facilitate their further functionalization under bioorthogonal conditions. Therefore, they should be useful probes for the investigation of PI and related biology, such as PI phosphorylation, PI interaction with other molecules in cells, and the functions of lipid structures in these processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Chemical Synthesis of Monolignols: Traditional Methods, Recent Advances, and Future Challenges in Sustainable Processes.
- Author
-
Tiz, Davide Benedetto, Tofani, Giorgio, Vicente, Filipa A., and Likozar, Blaž
- Subjects
CHEMICAL synthesis ,CHEMISTS ,PLANT growth ,PLANT development ,HYDROGEN atom ,LIGNINS - Abstract
Monolignols represent pivotal alcohol-based constituents in lignin synthesis, playing indispensable roles in plant growth and development with profound implications for industries reliant on wood and paper. Monolignols and their derivates have multiple applications in several industries. Monolignols exhibit antioxidant activity due to their ability to donate hydrogen atoms or electrons to neutralize free radicals, thus preventing oxidative stress and damage to cells. Characterized by their alcohol functionalities, monolignols present three main forms: p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. In nature, particularly in plants, monolignols with geometry (E) predominate over their Z counterparts. The methods for obtaining the three canonical monolignols, two less-common monolignols, and a monolignol analogue are addressed to present an overview of these phenol-based compounds, particularly from a synthetic standpoint. A SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis is used to explain the advantages and disadvantages of synthesizing monolignols, key alcohol-containing raw materials with enormous significance in both plant biology and industrial applications, using bench chemical methods. The uniqueness of this work is that it provides an overview of the synthetic pathways of monolignols to assist researchers in pharmaceutical and biological fields in selecting an appropriate procedure for the preparation of their lignin models. Moreover, we aim to inspire scientists, particularly chemists, to develop more sustainable synthetic protocols for monolignols. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Optimization of pulp production from groundnut shells using chemical pulping at low temperatures
- Author
-
Tirivaviri Augustine Mamvura, Gwiranai Danha, Langa Bright Moyo, N. Hlabangana, P. Musekiwa, and Geoffrey S. Simate
- Subjects
0301 basic medicine ,Bleach ,Response surface modelling ,Chemical pulping ,engineering.material ,Kappa number ,Lignin ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Hydrolysis ,0302 clinical medicine ,Chemical engineering ,stomatognathic system ,Low temperature ,Response surface methodology ,Chemical synthesis ,Natural product chemistry ,Cellulose ,lcsh:Social sciences (General) ,lcsh:Science (General) ,Dissolution ,Multidisciplinary ,Materials characterization ,Groundnut shells ,Pulp (paper) ,food and beverages ,Pulp and paper industry ,stomatognathic diseases ,030104 developmental biology ,chemistry ,engineering ,lcsh:H1-99 ,030217 neurology & neurosurgery ,lcsh:Q1-390 - Abstract
Paper production through chemical pulping has been identified as one of the ideal avenues of exploring the uses of groundnut shells as they are rich in cellulose. Ideally, the cellulose can be used to synthesize fibres that can be converted into useful paper products. In this study, chemical pulping was the chosen process for liberating the fibres as it is effective in dissolving lignin embedded within the cellulose. In addition, the fibres produced have superior physical properties compared to mechanical pulping. It is imperative that optimal conditions are identified for the chemical treatment process, in order to ensure that energy and chemical consumption are minimized. All these measures are aimed at reducing production costs and make chemical pulping economically viable, as compared to the mechanical pulping process which is less costly. Response surface methodology (RSM) was used in this study to evaluate the effect of three independent variables (cooking time, temperature, and sulphidity) on pulp yield and kappa number. These parameters are critical in the chemical pulping process and the optimal conditions obtained were 180 min, 100 °C and 23.6 wt.%, respectively. At the optimal cinditions, the pulp yield was 64.39wt% with a kappa number of 19.5. The results showed that all parameters investigated, had a statistically significant effect on the production of pulp. The increased cooking time was efficient in ensuring complete impregnation of the groundnut shells with chemicals for pulping and ensuring that the dissolution of lignin is not selective and does not result in dead spots inherently compromising the quality of the pulp. On the other hand, lower temperatures limited the peeling effect due to hydrolysis of carbohydrates which increased pulp yield due to a higher cellulose retention. Consequently, this contributed towards obtaining pulp that is well cooked, has a low bleach consumption and a higher quality., Chemical engineering; Chemical Synthesis; Materials Characterization; Natural product chemistry; Groundnut shells; chemical pulping; response surface modelling; low temperature; Lignin
- Published
- 2020
45. Evaluation of the Synthetic Scope and the Reaction Pathways of Proton‐Coupled Electron Transfer with Redox‐Active Guanidines in C−H Activation Processes
- Author
-
Olaf Hübner, Elisabeth Kaifer, Ute Wild, Hans-Jörg Himmel, and Petra Walter
- Subjects
Reaction mechanism ,oxidation ,010402 general chemistry ,01 natural sciences ,Chemical synthesis ,Redox ,oxidative coupling ,Catalysis ,C−H activation ,chemistry.chemical_compound ,Electron transfer ,redox chemistry ,Reactivity (chemistry) ,Full Paper ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,General Chemistry ,Full Papers ,Proton‐Coupled Electron Transfer ,electron transfer ,Combinatorial chemistry ,0104 chemical sciences ,Ferrocene ,Oxidative coupling of methane ,Proton-coupled electron transfer - Abstract
Proton‐coupled electron transfer (PCET) is currently intensively studied because of its importance in synthetic chemistry and biology. In recent years it was shown that redox‐active guanidines are capable PCET reagents for the selective oxidation of organic molecules. In this work, the scope of their PCET reactivity regarding reactions that involve C−H activation is explored and kinetic studies carried out to disclose the reaction mechanisms. Organic molecules with potential up to 1.2 V vs. ferrocenium/ferrocene are efficiently oxidized. Reactions are initiated by electron transfer, followed by slow proton transfer from an electron‐transfer equilibrium., There's a good PECT! Redox‐active guanidines are used in proton‐coupled electron transfer (PCET) reactions that involve C−H bond cleavage. The study reveals the scope and the mechanism of PCET reactions with and without addition of a strong acid. Substrates with potentials of up to 1.2 V versus ferrocenium/ferrocene could be oxidized in stepwise PCET processes initiated by electron transfer. Experiments with guanidine derivatives show the possibility of tuning the PCET reactivity.
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- 2020
46. Singlet‐Oxygen Generation by Peroxidases and Peroxygenases for Chemoenzymatic Synthesis
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Jan Kiebist, Kerstin Hoffmann-Jacobsen, Christian Mayer, Kim N. Ingenbosch, Philipp Süss, Ute Liebelt, Klaus Opwis, Melanie Dyllick-Brenzinger, D.S. Wunschik, Katrin Scheibner, Ralf Zuhse, Jochen S. Gutmann, Ulf Menyes, and Stephan Quint
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inorganic chemicals ,Chemie ,peroxidase ,010402 general chemistry ,Photochemistry ,environment and public health ,01 natural sciences ,Biochemistry ,Chemical synthesis ,Mixed Function Oxygenases ,chemistry.chemical_compound ,peroxygenase ,polycyclic compounds ,Molecular Biology ,Fluorescent Dyes ,chemistry.chemical_classification ,Reactive oxygen species ,Full Paper ,Molecular Structure ,Singlet Oxygen ,biology ,010405 organic chemistry ,Singlet oxygen ,organic chemicals ,Organic Chemistry ,Substrate (chemistry) ,Full Papers ,Fluorescence ,0104 chemical sciences ,Peroxidases ,chemistry ,Catalase ,Reagent ,biological sciences ,biology.protein ,Molecular Medicine ,fluorescence ,singlet oxygen sensor green ,chemo-enzymatic synthesis ,Peroxidase - Abstract
Singlet oxygen is a reactive oxygen species undesired in living cells but a rare and valuable reagent in chemical synthesis. We present a fluorescence spectroscopic analysis of the singlet‐oxygen formation activity of commercial peroxidases and novel peroxygenases. Singlet‐oxygen sensor green (SOSG) is used as fluorogenic singlet oxygen trap. Establishing a kinetic model for the reaction cascade to the fluorescent SOSG endoperoxide permits a kinetic analysis of enzymatic singlet‐oxygen formation. All peroxidases and peroxygenases show singlet‐oxygen formation. No singlet oxygen activity could be found for any catalase under investigation. Substrate inhibition is observed for all reactive enzymes. The commercial dye‐decolorizing peroxidase industrially used for dairy bleaching shows the highest singlet‐oxygen activity and the lowest inhibition. This enzyme was immobilized on a textile carrier and successfully applied for a chemical synthesis. Here, ascaridole was synthesized via enzymatically produced singlet oxygen., H2O2 to 1 O2 to… The formation of singlet oxygen from hydrogen peroxide by heme peroxidases and peroxygenases, but not catalases, is shown by fluorescence spectroscopy. The most active peroxidase, based on kinetic analysis using the fluorescent trap singlet‐oxygen sensor green, was applied in a chemo‐enzymatic synthesis of ascaridole.
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- 2020
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47. The Macrocycle versus Chain Competition in On‐Surface Polymerization: Insights from Reactions of 1,3‐Dibromoazulene on Cu(111)
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J. Michael Gottfried, Claudio K. Krug, Damian Nieckarz, Qitang Fan, and Paweł Szabelski
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surface chemistry ,010402 general chemistry ,Kinetic energy ,Ring (chemistry) ,Surface Chemistry | Hot Paper ,01 natural sciences ,Chemical synthesis ,Catalysis ,law.invention ,metal–organic frameworks ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,law ,Full Paper ,010405 organic chemistry ,Organic Chemistry ,General Chemistry ,Full Papers ,Azulene ,0104 chemical sciences ,macrocycles ,Polymerization ,chemistry ,Chemical physics ,chain structures ,polymerization ,Metal-organic framework ,Scanning tunneling microscope - Abstract
Ring/chain competition in oligomerization reactions represents a long‐standing topic of synthetic chemistry and was treated extensively for solution reactions but is not well‐understood for the two‐dimensional confinement of surface reactions. Here, the kinetic and thermodynamic principles of ring/chain competition in on‐surface synthesis are addressed by scanning tunneling microscopy, X‐ray photoelectron spectroscopy, and Monte Carlo simulations applied to azulene‐based organometallic oligomers on Cu(111). Analysis of experiments and simulations reveals how the ring/chain ratio can be controlled through variation of coverage and temperature. At room temperature, non‐equilibrium conditions prevail and kinetic control leads to preferential formation of the entropically favored chains. In contrast, high‐temperature equilibrium conditions are associated with thermodynamic control, resulting in increased yields of the energetically favored rings. The optimum conditions for ring formation include the lowest possible temperature within the regime of thermodynamic control and a low coverage. The general implications are discussed and compared to the solution case., The competition between macrocycle and chain formation in organometallic on‐surface polymerization can be steered by variation of coverage and temperature. The entropically favored chains are preferentially formed under non‐equilibrium conditions and high coverage, whereas the more stable macrocycles prevail when the on‐surface synthesis is performed in equilibrium at low coverages.
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- 2020
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48. Scalable Hybrid Synthetic/Biocatalytic Route to Psilocybin
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Alexander M. Sherwood, Miriam A. Rosenbaum, Claudius Lenz, Gundela Peschel, Janis Fricke, Dirk Hoffmeister, Lars Regestein, and Robert B. Kargbo
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Tryptamine ,kinase ,enzymes ,010402 general chemistry ,01 natural sciences ,Chemical synthesis ,Catalysis ,Psilocybin ,chemistry.chemical_compound ,medicine ,Bioorganic chemistry ,Humans ,bioorganic chemistry ,fermentation ,Mushroom ,Depressive Disorder, Major ,Psilocybe ,Indole alkaloid ,biology ,Full Paper ,010405 organic chemistry ,Chemistry ,phosphorylation ,Organic Chemistry ,General Chemistry ,Full Papers ,biology.organism_classification ,Combinatorial chemistry ,Tryptamines ,0104 chemical sciences ,Biosynthesis | Hot Paper ,Psilocin ,Biocatalysis ,biosynthesis ,Agaricales ,medicine.drug - Abstract
Psilocybin, the principal indole alkaloid of Psilocybe mushrooms, is currently undergoing clinical trials as a medication against treatment‐resistant depression and major depressive disorder. The psilocybin supply for pharmaceutical purposes is met by synthetic chemistry. We replaced the problematic phosphorylation step during synthesis with the mushroom kinase PsiK. This enzyme was biochemically characterized and used to produce one gram of psilocybin from psilocin within 20 minutes. We also describe a pilot‐scale protocol for recombinant PsiK that yielded 150 mg enzyme in active and soluble form. Our work consolidates the simplicity of tryptamine chemistry with the specificity and selectivity of enzymatic catalysis and helps provide access to an important drug at potentially reasonable cost., The benefits of bulk: Future use of psilocybin as a medication will entail increased demand. We present a gram‐scale synthetic/biocatalytic approach in which the mushroom kinase PsiK replaces tedious chemical phosphorylation. A pilot‐scale protocol to make three‐digit milligram amounts of pure and active recombinant PsiK available is also described.
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- 2020
49. Biological Characterization, Mechanistic Investigation and Structure‐Activity Relationships of Chemically Stable TLR2 Antagonists
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Thomas Rudolf, Gerhard Wolber, Péter Varga, Markus Tiemann, Jörg Rademann, Manuela S. Murgueitio, Maria Grabowski, Marcel Bermudez, and Günther Weindl
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Molecular model ,Pyrogallol ,Ligands ,01 natural sciences ,Biochemistry ,Chemical synthesis ,chemistry.chemical_compound ,Structure-Activity Relationship ,Drug Discovery ,Humans ,General Pharmacology, Toxicology and Pharmaceutics ,Receptor ,Cells, Cultured ,Pharmacology ,Innate immune system ,Dose-Response Relationship, Drug ,Molecular Structure ,Full Paper ,010405 organic chemistry ,Hydrogen bond ,molecular modeling ,Organic Chemistry ,Full Papers ,Combinatorial chemistry ,Toll-Like Receptor 2 ,structure-based design ,0104 chemical sciences ,TLR selectivity ,Toll-like receptors ,010404 medicinal & biomolecular chemistry ,TLR2 ,HEK293 Cells ,chemistry ,inflammation ,Molecular Medicine ,500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften ,Linker ,chemical synthesis - Abstract
Toll‐like receptors (TLRs) build the first barrier in the innate immune response and therefore represent promising targets for the modulation of inflammatory processes. Recently, the pyrogallol‐containing TLR2 antagonists CU‐CPT22 and MMG‐11 were reported; however, their 1,2,3‐triphenol motif renders them highly susceptible to oxidation and excludes them from use in extended experiments under aerobic conditions. Therefore, we have developed a set of novel TLR2 antagonists (1–9) based on the systematic variation of substructures, linker elements, and the hydrogen‐bonding pattern of the pyrogallol precursors by using chemically robust building blocks. The novel series of chemically stable and synthetically accessible TLR2 antagonists (1–9) was pharmacologically characterized, and the potential binding modes of the active compounds were evaluated structurally. Our results provide new insights into structure‐activity relationships and allow rationalization of structural binding characteristics. Moreover, they support the hypothesis that this class of TLR ligands bind solely to TLR2 and do not directly interact with TLR1 or TLR6 of the functional heterodimer. The most active compound from this series (6), is chemically stable, nontoxic, TLR2‐selective, and shows a similar activity with regard to the pyrogallol starting points, thus indicating the variability of the hydrogen bonding pattern., Undegraded: The 1,2,3‐triphenol motif of known TLR2 antagonists is highly susceptible to oxidation and excludes them from use in extended experiments under aerobic conditions. Herein, we report a rationally developed series of novel TLR modulators resulting in compound 6, a novel, chemically stable, nontoxic, TLR2‐selective antagonist.
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- 2020
50. Standardization and Control of Grignard Reactions in a Universal Chemical Synthesis Machine using online NMR
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Klas Meyer, Jakob Wolf, Artem Leonov, Martin Bornemann-Pfeiffer, Simon Kern, Davide Angelone, Franziska Emmerling, and Leroy Cronin
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Grignard ,Standardization ,Communication ,Process analytical technology ,Control (management) ,Formulations ,03-29-22 ,Control engineering ,Context (language use) ,Grignard reaction ,General Chemistry ,Chemputer ,process control ,User requirements document ,Chemical synthesis ,Communications ,process analytical technology ,Catalysis ,NMR spectroscopy ,chemical synthesis machine ,Tacit knowledge ,Fiction ,Process Control | Hot Paper ,Process control ,reproducibility - Abstract
A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small‐molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online‐NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements., A universal chemical synthesis platform was extended by online NMR to allow adjustments of the encoded reactions on the fly. The approach was demonstrated on the class of Grignard reactions showing robust analytical results under harsh conditions. Real‐time process analytics and the use of straightforward feedback control algorithm enhance the usability of available synthesis formula considering existing deviations.
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- 2021
- Full Text
- View/download PDF
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