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Ketanserin (KTS), a BCS class II drug, is used as an alpha-blocking serotonin antagonist. The drug decreases blood pressure by lowering peripheral vascular resistance. In order to improve its poor aqueous solubility, multicomponent solid forms of KTS with aliphatic acidic coformers such as maleic acid (MA), fumaric acid (FA), adipic acid (AA), and sulfamic acid (SA) were synthesized via wet granulation. The salts were characterized by XRD, DSC, TGA and single crystal XRD. Proton transfer from acidic coformers to the most basic piperidine nitrogen atom of KTS confirmed salt formation. KTS·FA and KTS·MA are anhydrous salts, while KTS·SA and KTS·AA are hydrates. KTS·SA crystallized as both monohydrate (MH) and dihydrate (DH), with the dihydrate being the more thermodynamically stable phase. The KTS hydrogen-bonded amide dimer is replaced by piperidinium⋯carboxylate/sulfonate ionic heterosynthons in the salts. Hirshfeld surface analysis quantified the non-covalent interactions governing the salt assembly. Solubility studies in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) revealed improved solubility for all salts compared to KTS, with the order being KTS·SA (DH) > KTS·FA > KTS·MA > KTS·AA > KTS in phosphate buffer. Slight solubility improvement was observed in acidic medium (pH 1.2). KTS salts maintained their integrity in phosphate buffer but transformed into their HCl salts under acidic conditions. The enhanced solubility of KTS·SA (DH) is attributed to higher ΔpKa, polar contacts, extended conformation, and ionic heterosynthons. These new solid forms of KTS present an opportunity to overcome solubility-related bioavailability challenges. [ABSTRACT FROM AUTHOR]

This work evaluates the use of zinc oxide nanorods as intensifiers of a latent heat thermal energy storage system working with adipic acid as the phase change material (PCM). By virtue of not participating directly in the solid–liquid and liquid–solid phase transition, ZnO-adipic acid composites (ZnO-adipic acid) possessed lower specific heat and latent heat. Our results have shown that the overall heat transfer coefficient during the freezing of PCM through heat transfer to a well-mixed liquid bath is amplified by 61%, when adipic acid is replaced with 2 wt.% ZnO-adipic acid. Heterogenous nucleation due to well-dispersed, ZnO nanorods caused this enhancement. The large enhancement in discharge rate of 2 wt.% ZnO-adipic acid during freezing overweighs higher degree of latent heat loss due to its repeated thermal cycling. The enhancement in overall heat transfer coefficient reported here (61%) is the highest reported so far for any latent heat thermal energy system employing adipic acid or its composites. [ABSTRACT FROM AUTHOR]

Semi‐aromatic nylon MXD6 shows superior mechanical strength and gas barrier properties. To improve its toughness and get sight into its excellent properties, a series of poly(m‐xylylene adipamide‐co‐isophthalamide) (MXD6/I) random copolyamides were synthesized using adipic acid, isophthalic acid (IPA) and m‐xylylene diamine as monomers via direct melt polycondensation. The effect of IPA content on the thermal, crystallization, heat resistant, mechanical, and barrier properties of the copolyamides were systematically investigated. The results showed that the increase of IPA content from 0 to 12 mol% resulted in a decrease in the melting point of the copolyamides from 238 to 217°C but the glass transition temperature (Tg) increased from 88 to 105°C. Correspondingly, the Vicat softening temperature decreased from 199.2 to 172.5°C. The crystallization rate of the copolyamides significantly decreased with the increase of the IPA content. The copolyamides had improved elongation and rupture energy and decent oxygen barrier properties with the introduction of IPA. It is expected that this study would guide design of MXD6 macromolecular chain structure to prepare high‐performance MXD6 materials. [ABSTRACT FROM AUTHOR]

This article presents the preparation of environmentally friendly water‐soluble lubricant additives. Adipic acid (AA), sebacic acid (SA) and dodecanedioic acid (DA) were individually subjected to esterification reactions with polyethylene glycol 1500 (PEG1500) to prepare a class of water‐soluble polyether esters (AAPEE1500, SAPEE1500 and DAPEE1500) (referred to as XAPEE1500s) that exhibit excellent water solubility and do not contain environmentally harmful elements. First, the molecular structure characterisation and functional group analysis of these additives will be conducted using an infrared spectrometer and a nuclear magnetic resonance spectrometer. Subsequently, the frictional properties of the additives in the base liquid (deionised water) will be investigated using an SRV‐V tribometer, Falex pin‐on‐disc tribometer and screw torque tester. The surface morphology of wear scars will be characterised and analysed using scanning electron microscopy (SEM) and a non‐contact 3D profilometer. Finally, the lubrication mechanism of the DAPEE1500 additive will be analysed using X‐ray photoelectron spectroscopy (XPS). The results indicate that the optimal lubrication performance is achieved when the added mass fraction of DAPEE1500 is at 3%. Compared with 0.5 wt% DAPEE1500, the average friction coefficient of 3 wt% DAPEE1500 decreased from 0.285 to 0.122, and the wear volume decreased from 25.52 × 10−5 μm3 to 10.96 × 10−5 μm3. The lubrication mechanism of polyether ester is the result of the combined action of its polar ester functional groups and long carboxylic acid chains in the structure. These polar functional groups can form a relatively firm adsorption film on the friction surface, while the long carboxylic acid chains act as a brush‐like isolating layer, thus demonstrating superior anti‐wear and anti‐friction performance. [ABSTRACT FROM AUTHOR]

In this study, hydrogen production through the hydrolysis, ethanolysis, and methanolysis reactions of NaBH4 using adipic acid as a catalyst was investigated for the first time. Adipic acid solutions were prepared with methanol and ethanol at concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 M. In these reactions, NaBH4-MR (methanolysis) and NaBH4-ER (ethanolysis) reactions were carried out at 30, 40, and 50 °C with NaBH4 concentrations of 1.25%, 2.5%, and 5%. Hydrolysis reactions (NaBH4-HR) were conducted at 0.1 M under the same conditions. In the ethanolysis and methanolysis reactions at 30 °C, total hydrogen conversion was achieved at 0.3 M, 0.4 M, and 0.5 M. However, in the hydrolysis reactions, total hydrogen production was only obtained at 50 °C. It was observed that in the NaBH4-MR and NaBH4-ER reactions, total hydrogen conversion could be achieved within 4–5 s. The utilization of adipic acid as a catalyst for hydrogen production from NaBH4 through ethanolysis and methanolysis reactions is proposed as a highly efficient and fast method, characterized by impressive conversion rates. [ABSTRACT FROM AUTHOR]

cis,cis-Muconic acid (MA) is a bio-based chemical that can be converted to direct replacement chemicals or performance-advantaged bioproducts. We recently engineered the bacterium Pseudomonas putida KT2440 for the co-utilization of glucose and xylose to produce MA. This study evaluates the effect of additional genetic modifications, media composition, and bioprocess strategy on MA titer, productivity, and yield in bioreactor cultivations. We achieve a MA titer of 47.2 g L−1, a productivity of 0.49 g L−1 h−1, and a yield of 0.50 C-mol C-mol−1 from glucose and xylose supplemented with 5% (v/v) corn steep liquor with a P. putida strain harboring the deletion of gacS. Additionally, we demonstrate efficient MA production from corn stover-derived sugars and scalability to 150 L bioreactors. Techno-economic analysis and life cycle assessment predict that adipic acid, derived from catalytic hydrogenation of MA, can achieve a selling price as low as $2.60 per kg, approaching cost parity and reducing greenhouse gas emissions by up to 80% relative to fossil carbon-based adipic acid. [ABSTRACT FROM AUTHOR]

The reactions of the angular ligand 4,4′-oxybis(N-(pyridin-3-yl)benzamide) (L1) and 1,4-naphthalenedicarboxylic acid (1,4-H2NDC) with divalent metal salts yielded three distinct coordination polymers (CPs): {[Zn2(L1)(1,4-NDC)2]·MeOH}n, 1, {[Cu(L1)(1,4-NDC)(H2O)]·3H2O}n, 2, and {[Cd(L1)(1,4-NDC)]·2H2O}n, 3. Complex 1 features a 2-fold interpenetrated 3D framework with the (412·63)-pcu topology, while complex 2 reveals a 1D triple-strained helical chain and complex 3 displays a 3-fold interpenetrated 3D framework with (66)-dia topology. Additionally, the reactions of the flexible ligand N,N′-bis(3-methylpyridyl) adipoamide (L2) afforded {[Co4(L2)0.5(1,4-NDC)3(H2O)3(µ3-OH)2]·EtOH·2H2O}n, 4, {[Zn2(L2)(1,4-NDC)2]·2CH3OH}n, 5, and [Cd(L2)(adipic)(H2O)]n (H2adipic = adipic acid), 6, exhibiting a self-catenated 3D framework with the (420·68)-8T32 topology, a 2D layer with the (413·62) − (4,4)IIb topology, and a 2D layer with the (44·62)-sql topology, respectively. The structural diversity observed in complexes 1–6 highlights the pivotal influence of the metal center on the degree of entanglement in CPs within mixed-ligand systems. The thermal stability and luminescent properties of complexes 1–3, 4, and 6 are also discussed. [ABSTRACT FROM AUTHOR]

Two ethanol-solvated adipate and succinate salts of carvedilol (CVD), a Biopharmaceutics Classification System class 2 drug, were synthesized by crystallizing ethanol with adipic acid (ADP) and succinic acid (SUA). Proton transfer from ADP and SUA to CVD and the presence of ethanol in the two novel compounds were confirmed using powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and single-crystal X-ray diffraction measurements. The two novel ethanol-solvated salts exhibited enhanced solubility and dissolution rates compared with pure carvedilol in phosphate buffer (pH 6.8). Additionally, the morphologies and attachment energies of the two novel compounds and pure CVD were calculated based on their single-crystal structures, revealing a correlation between attachment energy and dissolution rate. [ABSTRACT FROM AUTHOR]

This study determined the antioxidant and antibacterial activities of Thymus schimperi (Ts), Rhamnus prinoides (Rp), and Justicia schimperiana (Js) from Addis Ababa against MDR-Uropathogenic bacteria. Accordingly, Thymus schimperi had the highest total phenolic (TPC), flavonoid (TFC) and proanthocyanidin content. In Ts, the GC-MS analyses predicted 14 bioactive compounds. And among these, hexanedioic acid, bis(2-ethylhexyl) ester, thymol, and o-cymen-5-ol were the most predominant compounds, respectively. Six compounds were also predicted in Rp, where hexanedioic acid, bis(2-ethylhexyl) ester, β-D-glucopyranoside, methyl, and desulphosinigrin were the predominant, respectively. Whereas in the Js extract, five bioactive compounds were predicted, with hexanedioic acid, mono (2-ethylhexyl) ester, debrisoquine, and 8,11,14-heptadecatrienoate, methyl ester being predominant compounds, respectively. The extracts' TPC showed a strong negative correlation with the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay (r = −0.999; p = 0.023). In addition, the TFC correlated significantly with the ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) assay (r = 0.999; p = 0.032). Thymus schimperi showed the highest antibacterial activity against clinical isolates of Escherichia coli and Klebsiella pneumoniae ESBL at 1000 mg/mL, and Ts had the lowest MIC (4 mg/mL) among evaluated extracts against E. coli (ATCC25922). In conclusion, Ts and Rp possess higher predicted bioactive molecules, including antioxidant and antibacterial activities, which are potentially useful in treating urinary tract infections. [ABSTRACT FROM AUTHOR]

The efficient production of biobased organic acids is crucial to move to a more sustainable and eco-friendly economy, where muconic acid is gaining interest as a versatile platform chemical to produce industrial building blocks, including adipic acid and terephthalic acid. In this study, a Saccharomyces cerevisiae platform strain able to convert glucose and xylose into cis,cis-muconic acid was further engineered to eliminate C2 dependency, improve muconic acid tolerance, enhance production and growth performance, and substantially reduce the side production of the intermediate protocatechuic acid. This was achieved by reintroducing the PDC5 gene and overexpression of QDR3 genes. The improved strain was integrated in low-pH fed-batch fermentations at bioreactor scale with integrated in situ product recovery. By adding a biocompatible organic phase consisting of CYTOP 503 and canola oil to the process, a continuous extraction of muconic acid was achieved, resulting in significant alleviation of product inhibition. Through this, the muconic acid titer and peak productivity were improved by 300% and 185%, respectively, reaching 9.3 g/L and 0.100 g/L/h in the in situ product recovery process as compared to 3.1 g/L and 0.054 g/L/h in the control process without ISPR. [ABSTRACT FROM AUTHOR]

Five commercial lactic acid bacteria—Lactobacillus bulgaricus 57 (Lb57), Lactobacillus gasseri 07 (Lg07), Streptococcus thermophilus 08 (St08), Pediococcus pentosaceus 57 (Pp57), and Bifidobacterium adolescentis 68 (Bba68)—were employed to investigate their impact on physicochemical and nutritional properties of feijoa juice pretreated with enzymatic hydrolysis. The results showed that feijoa fruit juice was a favorable food matrix for probiotics and the viable counts remained above 9.0 log CFU/mL at the end of fermentation. Total soluble solids (TSS), vitamin C (VC), and sucrose were decreased, whereas glucose, quininic acid, adipic acid, and antioxidant capacity were increased by 36-h fermentation. Bba68 and St08 demonstrated robust malolactic conversion abilities, yielding over 1.65 mg/L of lactic acid. The phenolic content in feijoa juice varied significantly, with gallic acid reaching 16.12 mg/L and 16.46 mg/L after 36-h fermentation by Bba68 and St08, respectively. Compared to other strains, Bba68 displayed excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH) (2.68 mmol Trolox/L), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (6.60 mmol Trolox/L), and ferric ion reducing antioxidant potential (FRAP) (28.11 mmol Trolox/L) capacities. Pearson correlation analysis demonstrated that enhanced antioxidant activities positively correlated with gallic acid content. Furthermore, the functional evaluation of the probiotic revealed that Bba68 possessed the highest acid-producing capacity (14.50 g/L) and bile salt tolerance (3.04%). Given this, these results may offer a possible pathway for screening strains with specific functions and industrial-scale fermentation conditions to manufacture novel value-added feijoa fruit products. [ABSTRACT FROM AUTHOR]

Traditionally, most flexible food packaging is made of linear low‐density polyethylene (LLDPE) which cannot easily be recycled, nor will it degrade in a reasonable timescale. In this work, a biobased biodegradable polyester alternative was investigated as a possible replacement for LLDPE. High molecular weight poly (pentylene adipate‐co‐terephthalate) with a 40/60 adipic acid/terephthalic acid mole ratio was synthesized using direct esterification and polycondensation. Glycerol and hexane‐1,2,5,6‐tetrol were added as branching agents to better match the structure of the LLDPE which in turn might help the ability of these materials in film‐blowing. Thermal, mechanical, and rheological properties of the copolyesters were thoroughly investigated. All copolyesters had a weight‐average molecular weight of over 140,000 g/mol, which is necessary for proper rheology, and were thermally stable up to 350°C. The addition of branching agents led to a slight decrease in crystallinity, d‐spacing, melting temperature, enthalpy of melting, stress at break, and elongation at break. However, an increase in Young's modulus and complex viscosity at high frequency were observed compared to PPeAT60 without branching agent added. Although the improved crystallinity and mechanical properties of the copolyesters made them viable for film‐blowing, the slow crystallization rate creates a major challenge. Highlights: Linear and branched poly(pentylene adipate‐co‐terephthalate) (PPeAT) synthesized.Properties compared to commercial poly(butylene adipate‐co‐terephthalate) (PBAT).Glass and melting temperatures comparable to commercial PBAT.Extensional and shear viscosity comparable to commercial PBAT.PPeAT stiffness is factor of 2 higher than PBAT; ultimate properties similar. [ABSTRACT FROM AUTHOR]

The application and promotion of biodegradable plastics are hindered by the imbalance between their mechanical and degradation performance imbalance, as well as high costs. Herein, a series of poly(ethylene adipate‐co‐terephthalate) (PEAT) copolyesters with excellent mechanical and degradation properties are synthesized by one‐step melt polycondensation. The influence of the proportion of aliphatic groups in the molecular chain on the structure and properties, especially the degradation performance, of the copolyesters was studied. The molecular chain flexibility and degradability of PEAT increases with increasing of adipic acid content and decreasing of ET fragment length (LET). The comprehensive mechanical properties of PEAT60 can be comparable to traditional packaging material poly(butylene adipateco‐terephthalate) (PBAT). The degradation performance of PEAT can be adjusted the molecular chain structure. PEAT with LET < 3 exhibit degradation performance, and PEAT with LET < 2.2 exhibit significant degradation acceleration. The excellent mechanical and degradable properties of PEAT copolyester make it expected to be used in degradable packaging and other fields to help solve plastic pollution, while its lower cost will aid in the promotion of degradable materials. [ABSTRACT FROM AUTHOR]

A series of partially bio-based and biodegradable poly(propylene terephthalate-co-adipate) (PPTA) random copolymers with different components were prepared by the melt polycondensation of petro-based adipic acid and terephthalic acid with bio-based 1,3-propanediol. The microstructure, crystallization behavior, thermal properties, and enzymatic degradation properties were further investigated. The thermal decomposition kinetics was deeply analyzed using Friedman's method, with the thermal degradation activation energy ranging from 297.8 to 302.1 kJ/mol. The crystallinity and wettability of the copolymers decreased with the increase in the content of the third unit, but they were lower than those of the homopolymer. The thermal degradation activation energy E, carbon residue, and reaction level n all showed a decreasing trend. Meanwhile, the initial thermal decomposition temperature (Td) was higher than 350 °C, which can meet the requirements for processing and use. The PPTA copolymer material still showed excellent thermal stability. Adding PA units could regulate the crystallinity, wettability, and degradation rate of PPTA copolymers. The composition of PPTA copolymers in different degradation cycles was characterized by 1H NMR analysis. Further, the copolymers' surface morphology during the process of enzymatic degradation also was observed by scanning electron microscopy (SEM). The copolymers' enzymatic degradation accorded with the surface degradation mechanism. The copolymers showed significant degradation behavior within 30 days, and the rate increased with increasing PA content when the PA content exceeded 45.36%. [ABSTRACT FROM AUTHOR]

Self‐healing involves an autonomic response that repairs damage to living systems. In this study, polyethylene glycol (PEG) underwent aldehyde‐functionalization using the Albrigh Goldman oxidation technique. Flexible, dynamic crosslink points to encourage self‐healing are generated by the formation of acylhydrazone bonds formed between long‐chain PEG dialdehyde and adipic acid dihydrazide. Furthermore, methacrylated PEG was synthesized to support the polymer matrix through dynamic covalent bonds. The hydrogels exhibited self‐healing within the first 4 hours at room temperature and after 24 h. hydrogels with mechanical performance close to the original were obtained. They have good tensile and elongation strength and are well‐suited for interaction with living cells. [ABSTRACT FROM AUTHOR]

Electrosynthesis of adipic acid (a precursor for nylon-66) from KA oil (a mixture of cyclohexanone and cyclohexanol) represents a sustainable strategy to replace conventional method that requires harsh conditions. However, its industrial possibility is greatly restricted by the low current density and competitive oxygen evolution reaction. Herein, we modify nickel layered double hydroxide with vanadium to promote current density and maintain high faradaic efficiency (>80%) within a wide potential window (1.5 ~ 1.9 V vs. reversible hydrogen electrode). Experimental and theoretical studies reveal two key roles of V modification, including accelerating catalyst reconstruction and strengthening cyclohexanone adsorption. As a proof-of-the-concept, we construct a membrane electrode assembly, producing adipic acid with high faradaic efficiency (82%) and productivity (1536 μmol cm−2 h−1) at industrially relevant current density (300 mA cm−2), while achieving >50 hours stability. This work demonstrates an efficient catalyst for adipic acid electrosynthesis with high productivity that shows industrial potential. Here, authors use a membrane electrode assembly is conducted to produce adipic acid with high faradaic efficiency and productivity at an industrially relevant current density, while achieving >50 hours stability. [ABSTRACT FROM AUTHOR]

The 3-ketoacyl-CoA thiolase is the rate-limiting enzyme for linear dicarboxylic acids production. However, the promiscuous substrate specificity and suboptimal catalytic performance have restricted its application. Here we present both biochemical and structural analyses of a high-efficiency 3-ketoacyl-CoA thiolase Tfu_0875. Notably, Tfu_0875 displayed heightened activity and substrate specificity for succinyl-CoA, a key precursor in adipic acid production. To enhance its performance, a deep learning approach (DLKcat) was employed to identify effective mutants, and a computational strategy, known as the greedy accumulated strategy for protein engineering (GRAPE), was used to accumulate these effective mutants. Among the mutants, Tfu_0875N249W/L163H/E217L exhibited the highest specific activity (320% of wild-type Tfu_0875), the greatest catalytic efficiency (kcat/KM = 1.00 min-1 mM-1 ), the highest succinyl-CoA specificity (KM = 0.59 mM, 28.1% of Tfu_0875) and dramatically reduced substrate binding energy (− 30.25 kcal mol-1 v.s. -15.94 kcal mol−1 ). A structural comparison between Tfu_0875N249W/L163H/E217L and the wild type Tfu_0875 revealed that the increased interaction between the enzyme and succinyl-CoA was the primary reason for the enhanced enzyme activity. This interaction facilitated rapid substrate anchoring and stabilization. Furthermore, a reduced binding pocket volume improved substrate specificity by enhancing the complementarity between the binding pocket and the substrate in stereo conformation. Finally, our rationally designed mutant, Tfu_0875N249W/L163H/E217Lincreased the adipic acid titer by 1.35-fold compared to the wild type Tfu_0875 in shake flask. The demonstrated enzymatic methods provide a promising enzyme variant for the adipic acid production. The above effective substrate binding pocket engineering strategy can be beneficial for the production of other industrially competitive biobased chemicals when be applied to other thiolases. [ABSTRACT FROM AUTHOR]

Copyright of Conservar Património is the property of Associacao Profissional de Conservadores-Restauradores de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Conservar Património is the property of Associacao Profissional de Conservadores-Restauradores de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study aimed to fingerprint the physical manufacturing properties of five commonly used acid sources in effervescent systems for designing the formulation and process of such systems. The hygroscopicity, texture properties, rheological torque, compressibility, tabletability, etc., were investigated to inspect 'powder direct compression (DC)' and 'wet granulation and compression' properties of citric (CA), tartaric (TA), malic (MA), fumaric (FA), and adipic acid (AA). The DC ability was evaluated by the SeDeM expert system. The results indicated that all acid powders failed to meet flowability requirements for DC, and plastic deformation dominated during compression. Furthermore, CA exhibited strong hygroscopicity and punch sticking, while MA demonstrated the best tabletability. TA had a large wet granulation space and was relatively the most suitable for DC. AA was extremely hygroscopic, and its flowability improved significantly as particle size increased. Finally, FA displayed the lowest hygroscopicity and ejection force as well as great compressibility and wet granulation space, and did not exhibit punch sticking, while the granule fragments dissolved slowly during disintegration. Generally speaking, the formulation or granulation affected the tabletability, indicating that pairing with other acids or suitable fillers could potentially improve its disadvantages. These multidimensional assessments effectively reduce the pre-exploration and enhance the efficiency of the development of effervescent systems. [ABSTRACT FROM AUTHOR]

This article discusses the use of perfluorinated sulfamides in various technological processes. The potential of aminotoxane as a catalyst in the cyclohexane oxidation process was studied. The use of aminotoxane significantly shifts the distribution of target products in cyclohexane oxidation, favoring increased alcohol formation. This catalytic system is distinct from those involving crown ethers and polyglycols, suggesting a specific mechanism of influence by perfluorinated sulfamides on the intermediate stages of radical-chain oxidation. For the by-product adipic acid, which is formed in significant amounts, a complex method of utilizing cyclohexane oxidation products is proposed. Specifically, esterification of adipic acid with alcohol was performed, resulting in the production of dibutyl adipinate, a valuable raw material for plasticizer manufacturing. The yield of dibutyl adipinate was 57.6%. The study found that cyclohexane oxidation in the presence of a binary catalyst, cobalt naphthenate–aminotoxane, results in an increased oxidation rate, a threefold reduction in ester and acid selectivity, and a twofold increase in cyclohexanol selectivity compared to oxidation with cobalt naphthenate alone. [ABSTRACT FROM AUTHOR]

Abstract This work evaluates the use of zinc oxide nanorods as intensifiers of a latent heat thermal energy storage system working with adipic acid as the phase change material (PCM). By virtue of not participating directly in the solid–liquid and liquid–solid phase transition, ZnO-adipic acid composites (ZnO-adipic acid) possessed lower specific heat and latent heat. Our results have shown that the overall heat transfer coefficient during the freezing of PCM through heat transfer to a well-mixed liquid bath is amplified by 61%, when adipic acid is replaced with 2 wt.% ZnO-adipic acid. Heterogenous nucleation due to well-dispersed, ZnO nanorods caused this enhancement. The large enhancement in discharge rate of 2 wt.% ZnO-adipic acid during freezing overweighs higher degree of latent heat loss due to its repeated thermal cycling. The enhancement in overall heat transfer coefficient reported here (61%) is the highest reported so far for any latent heat thermal energy system employing adipic acid or its composites.

Transcription factor (TF)-based biosensors that connect small-molecule sensing with readouts such as fluorescence have proven to be useful synthetic biology tools for applications in biotechnology. However, the development of specific TF-based biosensors is hindered by the limited repertoire of TFs specific for molecules of interest since current construction methods rely on a limited set of characterized TFs. In this study, we present an approach for engineering the specificity of TFs through a computation-based workflow using molecular docking that enables targeted alteration of TF ligand specificity. Using this method, we engineer the LysR family BenM TF to alter its specificity from its cognate ligand cis,cis-muconic acid to adipic acid through a single amino acid substitution identified by our computational workflow. When implemented in a cell-free system, the engineered biosensor shows higher ligand sensitivity, expanding the potential applications of this circuit. We further investigate ligand binding through molecular dynamics to analyze the substitution, elucidating the impact of modulating a single amino acid position on the mechanism of BenM ligand binding. This study represents the first application of biomolecular modeling methods for altering BenM specificity and for gaining insights into how mutations influence the structural dynamics of BenM. Such methods can potentially be applied to other TFs to alter specificity and analyze the dynamics responsible for these changes, highlighting the applicability of computational tools for informing experiments. In addition, our developed adipic acid biosensor can be applied for the identification and engineering of enzymes to produce adipic acid.

Leaf epicuticular waxes provide important anatomical and chemical defences against fungi that infect leaves. In this study we analysed the leaf wax composition of Eucalyptus grandis × Eucalyptus urophylla hybrids with contrasting susceptibilities to Teratosphaeria leaf blight (TLB) caused by Teratosphaeria destructans, one of the most important foliar diseases of Eucalyptus. The Eucalyptus cuticular wax was extracted from non‐inoculated and inoculated genotypes with different levels of susceptibility to TLB and analysed by gas chromatography–mass spectrometry. The results showed that a triterpenoid, cycloartenol (CAS), was abundant in a resistant genotype and that hexanedioic acid content increased in the resistant genotypes in response to T. destructans infection. In contrast, palmitic acid was significantly more abundant in the inoculated highly susceptible genotype. In‐vitro and in‐planta T. destructans spore germination assays with pure compounds, showed that CAS and hexanedioic acid significantly inhibited spore germination. Application of these two compounds to the leaves of a susceptible host also significantly increased resistance to infection. In contrast, palmitic acid promoted spore germination and, when applied to the leaves of a resistant genotype, increased colonization by the pathogen. This is the first study providing insights into differences in the leaf wax composition of hosts with different levels of susceptibility to T. destructans. It also showed that leaf wax compounds can modulate spore germination and, ultimately, host resistance to infection. [ABSTRACT FROM AUTHOR]

This work describes our recent PCB-based plasmonic nanostructured platform patent (US 11,828,747B2) for the detection of biomarkers in breast cancer serum (BCS). A 50 nm thin gold film (TGF) was immersion-coated on PCB (i.e., PCB-TGF) and immobilized covalently with gold nanourchin (GNU) via a 1,6-Hexanedithiol (HDT) linkage to produce a plasmonic activated nanostructured thin film (PANTF) platform. A label-free SERS immunosensor was fabricated by conjugating the platform with monoclonal HER-II antibodies (mAb) in a directional orientation via adipic acid dihydrazide (ADH) to provide higher accessibility to overexpressed HER-II biomarkers (i.e., 2+ (early), 3+ (locally advanced), and positive (meta) in BCS. An enhancement factor (EF) of 0.3 × 105 was achieved for PANTF using Rhodamine (R6G), and the morphology was studied by scanning electron microscopy (SEM) and atomic force microscope (AFM). UV-vis spectroscopy showed the peaks at 222, 231, and 213 nm corresponding to ADH, mAb, and HER-II biomarkers, respectively. The functionalization and conjugation were investigated by Fourier Transform Near Infrared (FT-NIR) where the most dominant overlapped spectra of 2+, 3+, and Pos correspond to OH-combination of carbohydrate, RNH2 1st overtone, and aromatic CH 1st overtone of mAb, respectively. SERS data were filtered using the filtfilt filter from scipy.signals, baseline corrected using the Improved Asymmetric Least Squares (isals) function from the pybaselines.Whittaker library. The results showed the common peaks at 867, 1312, 2894, 3026, and 3258 cm−1 corresponding to glycine, alanine ν (C-N-C) assigned to the symmetric C-N-C stretch mode; tryptophan and α helix; C-H antisymmetric and symmetric stretching; NH3+ in amino acids; and N-H stretch primary amide, respectively, with the intensity of Pos > 3+ > 2+. This trend is justifiable considering the stage of each sample. Principal Component Analysis (PCA) and Linear Discrimination Analysis (LDA) were employed for the statistical analysis of data. [ABSTRACT FROM AUTHOR]

• Analysis of Iyengaria stellata for its nutritional composition. • Detection of chemical constituents through GC-MS, FT-IR, Total Flavonoid and Phenolic contents. • Evaluation of pharmacological potential for hypoglycemic activity. • Evaluation of potential for pharmacological antimicrobial. • Evaluation of pharmacological potential for antioxidant. Seaweeds have gained significant attention for their bioactive compounds and extensive use in pharmaceuticals, nutraceuticals and cosmeceuticals. Therefore, comprehensive analysis was conducted to investigate the nutritional composition, identify and quantify the Phyco-chemicals and to evaluate the pharmacological potential using hypoglycemic, antimicrobial and antioxidant activities of Iyengaria stellata extract. The results of nutritional analysis revealed 39.72±2.60 % total ash, 14.54±0.44 % crude fat, 9.61±0.60 % proteins, 5.29±0.52 % crude fibers, 10.49±1.00 % moisture content, and total energy was 108.26±2.01 Kcal 100 g −1 of dry powder. Approximately, 15 compounds were tentatively detected in ethyl acetate extract with major compounds being Pentadecanoic acid, 14-methyl-, easter (31.62 %), (Z) -9- stearic acid, methyl easter (13.36 %), Elaidic acid, methyl easter (11.46 %), Phytol (6.31 %), n -Hexadecanoic acid (7.47 %), Linolelaidic acid, methyl ester (5.64 %) and 1-octadecyne (5.34 %). Similarly, n -butanol extract contained 16 compounds with primary compounds being Hexadecanoic acid, methyl ester (25.96 %), Elaidic acid methyl ester (21.39 %), Linolelaidic acid methyl ester (11.53 %), Octadecanoic acid, methyl ester (5.89 %), and Hexanedioic acid, dioctyl ester (5.26 %). FT-IR analysis revealed the presence of similar groups of compounds i.e. alcohols, phenols, lipids, carboxylic acids, amines, aromatics, ketones and halogens. Total phenolic contents (TPC) in ethyl acetate and n -butanol extract were measured as 2.982±0.876 mg GAEg−1 and 1.538±0.711 mg GAE g −1, whereas Total Flavonoids contents (TFC) were 2.058 ± 0.121 mg QE g −1 and 1.614 ± 0.643 mg QE g −1, respectively. Ethyl acetate extract exhibited more antioxidant potential with an IC 50 (2.59±1.34) compared to n -butanol extract (2.75±1.60). Moreover, n -butanol extract exhibited strong antimicrobial activity. The most susceptible strains were E. coli, S. aureus and P. aeruginosa. In terms of in-vivo hypoglycemic activity, the n -butanol extract proved to be more effective which significantly reduced the blood glucose level up to 226.17±3.43, 201.33±4.63 and 265.17±3.92 at 300, 200 and 100 mg kg−1 doses respectively after 24 h. In conclusion, the seaweed I. stellata exhibited significant potential in terms of its antioxidant, antimicrobial, and hypoglycemic properties. [ABSTRACT FROM AUTHOR]

Context: Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic. It was introduced to the plastics market in 1998 and since then has been widely used around the world. The main idea of this research is to perform quantum chemical calculations to study the potential toxicity of PBAT and its degradation products. We analyzed the electron transfer capacity to determine its potential toxicity. We found that biodegradable products formed with benzene rings are as good electron acceptors as PBAT and OOH•. Our results indicate that the biodegradation products are potentially as toxic as PBAT. This might explain why biodegradation products alter the photosynthetic system of plants and inhibit their growth. From this and other previous investigations, we can think that biodegradable plastics could represent a potential environmental risk. Methods: All DFT computations were performed using the Gaussian16 at M062x/6–311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as response functions. [ABSTRACT FROM AUTHOR]

2,5-Furandicarboxylic acid (FDCA) is one of the most promising biodegradable substitutes for fossil-derived terephthalic acid (PTA) and adipic acid. The production of FDCA from biomass-derived 5-hydroxymethylfurfural (HMF) is significant and has attracted great attention. However, the major challenge lies in the development of a non-precious metal-based catalyst system without employing a homogeneous base. Herein, we successfully prepared an atomically dispersed Fe–N–C/γ-Al2O3 catalyst, which affords superior catalytic performance in terms of activity and stability with a FDCA yield of 99.8% and reusability of five recycle times in the catalytic oxidation of HMF to FDCA under base-free mild conditions. Based on controlled experiments and complementary characterization studies, we found that the atomically dispersed medium-spin Fe–N5 active sites together with the surface acidic/basic sites of alumina synergistically enhanced the catalytic activity and selectivity towards FDCA under base-free conditions. Our process eliminates the employment of expensive oxidants and corrosive bases, leading to economic and green biomass transformations. [ABSTRACT FROM AUTHOR]

This work describes the comparison of the catalytic performances of α‐MnO2 nanorods synthesized by a facile hydrothermal approach at varying temperatures (140–200 °C). The structure and morphology of these nanorods were analyzed by XRD, N2‐physisorption, NH3‐TPD, Raman, SEM, HRTEM, and XPS. The prepared α‐MnO2 nanorods also performed exceptionally well in the catalytic oxidation of cyclohexanone to dicarboxylic acids under mild reaction conditions. The characterization results conferred that there is a significant influence of hydrothermal temperatures on the textural properties, morphology, and catalytic activity. Notably, the α‐MnO2 nanorods obtained from 180 °C hydrothermal conditions outperformed other catalysts with 77.3 % cyclohexanone conversion and 99 % selectivity towards acid products such as adipic acid (AA), glutaric acid (GA) and succinic acid (SA). The improved catalytic activity may be attributed to the interaction of the bifunctional Mn3+/4+ redox metal centres and surface acidic sites. The present oxidation reaction was found to be a promising eco‐benign process with high selectivity for the production of commercially significant carboxylic acids from cyclohexanone. [ABSTRACT FROM AUTHOR]

Toward high‐strength bio‐based polyamide 56 (PA56) fiber, we first in situ precipitate graphene oxide (GO), adipic acid and 1,5‐pentanodiamine together by reaction crystallization in ethanal to obtain PA56 salt/GO particles with well dispersed GO, then prepare PA56/GO nanocomposite with PA56 salt/GO via solvent‐free polymerization including solid‐state prepolycondensation and melt polycondensation. Finally, PA56/GO nanocomposite fiber is prepared by extrusion drawing. With 0.2 wt% GO, the tensile strength of PA56/GO fiber reaches 1050 MPa, which is 3.3 times that of pure PA56 fiber. Furtherly, we add PA56/GO with high GO content to commercial PA56 to prepare the hybrid fiber, of which the tensile strength reaches 1248 MPa. The great improvement is mainly due to the good dispersion of GO in the whole process, which increases the heterogeneous nucleation in favor of higher and oriented PA56 crystallization. Highlights: Bio‐based PA56/GO nanocomposite fiber with 1.2 GPa strength has been prepared.PA56 salt/GO particles with well‐dispersed GO are in situ precipitated.Solvent‐free polymerization is used instead of solution melt polymerization.Well‐dispersed GO results in high and oriented crystallinity of PA56/GO fiber.Tensile strength of PA56/GO fiber is 2.3 times that of commercial PA56 fiber. [ABSTRACT FROM AUTHOR]

Using the previously engineered adipate-secreting Escherichia MG1655 lacIQ, ∆ackA-pta, ∆poxB, ∆ldhA, ∆adhE, PL-SDφ10-atoB, Ptrc-ideal-4-SDφ10-fadB, ∆fadE, PL-SDφ10-tesB, ∆yciA, Ptrc-ideal-4-SDφ10-fabI, PL-SDφ10-paaJ, ∆aceBAK, ∆glcB as the core strain, the derivatives capable of enhanced synthesis of the target compound from glucose via the reversed fatty acid β-oxidation pathway were obtained. The respective effect was achieved due to the intensification of the tricarboxylic acid cycle in the cells. Prevention of multiple cycle turnovers, resulting from the inactivation of succinate dehydrogenase, had no pronounced effect on the formation of adipic acid by the recombinant. Upon intensification of the cycle due to enhancing anaplerotic oxaloacetic acetic acid formation from phosphoenolpyruvate, resulting from the increased expression of the native ppc gene, the synthesis of adipic acid increased by 1.2-fold up to ~390 μM. Enabling the formation of oxaloacetate from pyruvic acid, by introducing heterologous Bacillus subtilis pyruvate carboxylase in the cells , resulted in a 1.5-fold intensification of the cycle, concomitantly with the proportional increase in adipic acid secretion to ~496 μM. Subsequent inactivation of sdhAB genes in the strain increased the secretion of the target compound only slightly, and the adipic acid titer reached ~520 μM. The obtained data indicated a direct dependence of the efficiency of adipic acid synthesis by the engineered strains on the degree of intensification of the tricarboxylic acid cycle. [ABSTRACT FROM AUTHOR]

The oxidation of cyclohexanol/cyclohexanone with nitric acid as a fast and highly exothermic process was hard to control at low molar ratios of oxidant to organic substrate even in microreactors. Process of runaway gas generation was observed due to the local hot spots, which decreased the selectivity of adipic acid. Additional gas was introduced into microreactors before the reaction, changing the previous wave annular flow to the uniform slug flow. Through the microscopic high‐speed photography and CFD simulation, it was found that the internal convection made the reactant molecules in the aqueous slug distribute evenly instead of gathering near the interface before, thus eliminating the local hot spots and stabilizing the hydrodynamic characteristics. The reaction performance was evaluated under different conditions, and a higher adipic acid selectivity of 93.6% was achieved at a molar ratio of 6.7 with the combination of microreactors and conventional reactors. [ABSTRACT FROM AUTHOR]

A lot of research is constantly underway in the world to develop new or improve the current processes of the chemical industry to make them more effective and environmentally friendly. The described research on the oxidation of cyclohexane or cyclohexanone to adipic acid with a coupled action of UV radiation and oxygen–ozone mixture, instead of the currently used oxidation with HNO3, is part of this trend. Gas chromatography was used to determine process indicators, such as cyclohexane conversion and selectivity to AA, which exceeded 50% at 25 oC, after 16 h. This method can also be used for the preparation of other dicarboxylic acids from cycloalkanes, which proves its universal character.

Adipic acid is an industrially important dicarboxylic acid and an essential precursor in the synthesis of Nylon-6,6. Due to the environmental impact associated with the current synthetic methods for Nylon-6,6 production, greener alternatives based on renewable and bio-based feedstocks are needed. In the present study, the potential of two Pseudomonas putida strains engineered for muconic acid accumulation was used to produce adipic acid from the lignin-derived aromatic compound guaiacol. This was achieved by expressing genes enabling the conversion of guaiacol to catechol in the first strain, and the conversion of muconic acid to adipic acid via expression of the Bacillus coagulans enoate reductase gene in the second strain. Through process engineering, a 2-step production was designed in which 2.93 mM bio-adipic acid was produced, with a yield of 0.57 mol/mol. This is the first demonstration that process and strain engineering can be combined to obtain a complete bio-based route for adipic acid production from depolymerized lignin compounds using the robust P. putida chassis.

Supramolecular self-assembly–directed two unique organogels were achieved by varying gel-immobilized solvents. One gel is comprised of adipic acid (ADP) and triethanolamine (TEA) in pure dimethylformamide medium (i.e., ADP-TEA-DMF), while the other is formed from the combination of adipic acid and triethanolamine in a 1 : 1 mixed solvent system of DMF and acetonitrile (i.e., ADP-TEA-DMF-MeCN). Furthermore, we observed robust crystallization behaviour under the different stoichiometric conditions of adipic acid with triethanolamine in pure dimethylformamide (i.e., Crystal-DMF) and in pure dimethyl sulfoxide (i.e., Crystal-DMSO). To evaluate the mechanical strength and viscoelastic attributes, rheological experiments were executed on these supramolecular organogels of ADP-TEA-DMF and ADP-TEA-DMF-MeCN. Additionally, comprehensive microstructural analyses were conducted in order to unravel the architectural variations arising from the involvement of different solvent-directed semi-solid gel-state. Scanning electron microscopy (FESEM) images of xerogel specimens obtained from the two organogels revealed distinctive morphological patterns. Notably, perceptible variations in the morphology were also observed in both the crystalline phases. The crystal structure of both the crystalline phases (i.e., Crystal-DMF and Crystal-DMSO) were explored using single crystal X-ray diffraction study at 296 K for Crystal-DMF and under liquid nitrogen atmosphere for Crystal-DMSO. Crystal-DMF and Crystal-DMSO have identical crystal structures that are composed of the adipate dianion (ADP2−) and the protonated triethanolamine (TEAH+). The crystal engineering pattern of Crystal-DMSO was elucidated through this study. These findings of versatile organogelation and robust crystallization emphasize the significance of solvent polarity and its diversity in attaining both the gel and crystalline phases. The organogel-formation strategy of ADP-TEA-DMF and ADP-TEA-DMF-MeCN was unravelled using infrared spectroscopic analyses. ESI-Mass spectral studies demonstrate the basic gel-constructing units, which are repeating to offer stable organogels. Thus, the solvent and the gelator concentration-directed organogelation process and the robust crystal-formation strategy are critically visualized in this study. [ABSTRACT FROM AUTHOR]

Smart materials represent an emerging and highly exploited category, particularly in the creation of textiles that can sense and respond to various external stimuli, such as temperature or humidity. This study introduces for the first time the hygroscopic elongation and drying shrinkage properties of stimulus-responsive single-component polyamide (PA) fibers copolymerized with polyetherdiamine and diethylenetriamine (DETA). PA copolymers containing 5-15% polyetherdiamine were comprehensively characterized, including nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT-IR), relative viscosity, and differential scanning calorimetry (DSC) analyses. Subsequently, these PA copolymers were successfully melt-spun into fibers and knitted into double-layered fabrics. PA fibers containing 15% polyetherdiamine showed significant results, with a moisture-absorbing elongation of 15.6% and a drying shrinkage of 94.9%. The Qmax and moisture regain of the PA fabric are 0.206 W·cm-2 and 4.4%, respectively. These moisture-driven, fiber-based smart textiles exhibit changes in breathability and shape retention at different humidity levels, thereby maintaining a more comfortable microclimate. Such textiles have great potential for widespread use in clothing, helping to improve comfort and adaptability. [ABSTRACT FROM AUTHOR]

Two isolates of Roseateles were discovered in soil samples collected from Uiwang-si, Gyeonggi-do, Republic of Korea. These isolates exhibited rod-shaped morphology and were facultatively anaerobic, non-motile, and tested positive for oxidase and catalase. Designated as strains R3-3T and R3-11, their growth was hindered by NaCl concentrations exceeding 0.5%, while their optimal growth conditions were observed at temperatures ranging from 25 °C to 30 °C and pH levels between 7.0 and 9.0. Both strains exhibited positive results for the hydrolysis of Tween 80 and DNA, but tested negative for starch, casein, chitin, and gelatin hydrolysis. Additionally, they assimilated L-Arabinose, D-mannitol, and D-Maltose, while exhibiting negative results for the fermentation of D-glucose, esculin ferric citrate, D-mannose, N-acetyl-glucosamine, potassium gluconate, capric acid, adipic acid, trisodium citrate, and phenylacetic acid. The DNA G+C content of strain R3-3T was measured at 67.5 mol%. Comparative analysis revealed that the average nucleotide identity (ANI) values between R3-3T and the Roseateles type strains ranged from 75.14% to 78.30% while the digital DNA-DNA hybridization (dDDH) values ranged from 20.70% to 22.70%. Consequently, based on comprehensive genomic, chemotaxonomic, phenotypic, and phylogenomic evaluations, the isolated strains have been designated as a new species within the genus Roseateles, named Roseateles agri sp. nov. (with type strain R3-3T = KACC 23678T = NBRC 116681T). [ABSTRACT FROM AUTHOR]

Polyamide is a thermoplastic polymer widely used for several applications, including cables in offshore oil and gas operations. Due to its growing annual production worldwide, this poorly biodegradable material has been a source of pollution. Given this scenario, the need has arisen to develop environmentally friendly techniques to degrade this waste, and biotechnology has emerged as a possible solution to mitigate this problem. This study aimed to investigate the potential of Yarrowia lipolytica to biodepolymerize polyamide fibers (PAF). Microbial cultures were grown in shaken flasks containing different concentrations of PAF (0.5 and 2 g·L−1) and in a bioreactor with and without pH adjustment. PAF mass loss was up to 16.8%, achieved after 96 h of cultivation in a bioreactor without pH adjustment. Additionally, NMR analyses revealed that the amorphous regions of PAF, which are more susceptible to depolymerization, were reduced by 6% during cultivation. These preliminary results indicate the biotechnological potential of Y. lipolytica to depolymerize PAF. [ABSTRACT FROM AUTHOR]

Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite. [ABSTRACT FROM AUTHOR]

The global market of fossil carbon-derived adipic acid (AA) was over 3 million tons in 2022, emitting 3.1 million tons of the potent greenhouse gas N2O. Alternative biomass-derived feedstocks offer a sustainable option to replace fossil carbon, but alternative pathways for AA synthesis are also required to curb the substantial emissions associated with the process. A novel and sustainable approach to synthesize AA is by coupling biomanufacturing and electrocatalysis. Biologically-produced cis,cis-muconic acid (ccMA) from sugars and lignin monomers has recently gained significant attention as a precursor to AA, as it can be electrochemically hydrogenated to AA using water-derived (instead of fossil-derived) hydrogen and electricity generated from wind energy. For the first time in literature, we demonstrate appreciable electrochemical production of AA using supported palladium nanoparticles. The performance of this system contrasts with that of palladium foil or platinum-based catalysts, which produced little AA. Density functional theory calculations on model surfaces of palladium and platinum suggest that the reduction of ccMA to trans-3-hexenedioic acid occurs through an outer sphere proton-coupled electron transfer mechanism, while subsequent reduction to AA preferentially occurs on surface terrace sites. Our calculations also explain the exceptional performance of palladium nanoparticles compared to palladium- and platinum-based foils, attributing the more favorable activation energy barriers found on palladium terraces to the relatively moderate binding strength of adsorbed species. These results suggest structure-sensitive catalyst design strategies that maximize the exposure of terrace atoms for further improvement of the ccMA electrochemical hydrogenation process. [ABSTRACT FROM AUTHOR]

A series of seven novel amorphous amides and polyamides were synthesized from four biodegradable carboxylic acids by direct polycondensation with aliphatic diamines using Yamazaki-Higashi phosphorylation. Aliphatic carboxylic acids like acrylic acid, lactic acid, and adipic acid whereas aromatic carboxylic acid like terephthalic acid were reacted with ethylenediamine and diamino-propane respectively. The monocarboxylic acids yielded amides, whereas the dicarboxylic acids formed polyamides. The obtained products were characterized by FT-IR, 1H NMR, LCMS, SEM, TGA, and DSC along with microbial biodegradation. The TGA thermogram comparison studies show a decrease in thermal degradation with an increase in the aliphatic chain. Also, the introduction of an aromatic ring decreases degradability. Glass transition of aliphatic polyamide at 140 °C has negligible melting endotherm. Also, the samples were structurally degraded after 15 days of biological treatment which was confirmed via FT-IR. [ABSTRACT FROM AUTHOR]

Polyamide 66 was extensively utilized in various applications contributed by its excellent mechanical performance and outstanding durability. However, its high crystallinity renders it to have low transparency, which seriously limits its application in optical devices. Herein, a highly transparent polyamide (PA) 66-based copolymer was reported using 4,4′-diaminodicyclohexylmethane (PACM), adipic acid, and polyamide 66 salt as the reaction monomers. Wide-angle X-ray diffraction (WAXD) analysis revealed that the crystal phase of the synthesized PA66/PACM6 displayed a clear transition from α to γ as the PACM6 increased accompanied by a decreased intensity in the diffraction peak of the copolymer, whose transmittance was successfully adjusted reaching as high as 92.5% (at 550 nm) when the PACM6 was 40 wt%. Moreover, the copolymer with a higher content of PACM6 exhibited larger toughness. On the other hand, the biaxially oriented films of PA66/PACM6 (20 wt%) were also prepared, and it was found that the transparency of the PA66/PACM6 copolymer could be further enhanced via adjusting the stretching ratio of the film. Furthermore, the mechanical strength of the biaxially oriented PA66/PACM6 was also improved with the increase in the orientation degree in the stretching process, indicating that the physical properties of the transparent PA66 were significantly influenced by its alicyclic structure, and the introduction of PACM into PA66 was capable of effectively improving the optical and crystalline characteristics of PA66, revealing that the synthetic strategy has great potential for guiding the design and development of transparent polyamide materials. [ABSTRACT FROM AUTHOR]

Aldaric acids are becoming valuable platform chemicals in bioeconomy and circular economy approaches. Among them, mucic acid (meso‐galactaric acid) is gaining industrial attention as a bio‐based precursor of adipic acid found in polyamides, and of 2,5‐furan dicarboxylic acid, a valuable substitute for terephthalic acid in polyesters. A combination of detailed experimental protocols and conditions with DFT computational calculations for the synthesis of mucic acid from galactose are herein described. The product is obtained by reaction with diluted aqueous nitric acid as the oxidizing agent and the reaction medium. Optimized reaction conditions require 5 M nitric acid, 95 °C, galactose/HNO3 molar ratio 1 : 9, 100 g/L galactose concentration in the reaction medium. Computational calculations suggest that the oxidation mechanism may involve a contextual oxygen protonation and nitrate nucleophilic attack, leading to the oxidized product. The proposed mechanism requires a stoichiometry of 6 moles of nitric acid per galactose mole, albeit both experimental and computational data evidence that proton excess may be necessary to start the reaction. The reported study gives useful insights for the production of galactaric acid. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the use of direct heterogeneous esterification method of extracted fibers from Leptadenia pyrotechnica khimp (Leptadenia pyrotechnica) and date palm tree (Phoenix dactylifera L.) using adipic and citric acids. Homogeneous esterification leads to the degradation of lignocellulosic material, making it impossible to obtain a pure ester of extracted crude fiber by this method. Methods. The esterification reaction was carried out from three samples of the plant Leptadenia pyrotechnica, Phoenix dactylifera L. leaf, and fiber) were extracted as crude fibers and used in the heterogeneous esterification process. The total esterified fibers were six esters (each sample esterified with citric and adipic acid). The study employed ordinary laboratory equipment together with Fourier Transformation Infrared (FTIR) spectroscopy. The results showed that the ester contents were in the range 21.6% to 28%. The degree of substitutions was in the range 0.38 to 0.57. Conclusion. This process was simple and effective in producing esterified extracted plants fibers with a desirable degree of substitution.

In this study, hydrogen production through the hydrolysis, ethanolysis, and methanolysis reactions of NaBH4 using adipic acid as a catalyst was investigated for the first time. Adipic acid solutions were prepared with methanol and ethanol at concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5 M. In these reactions, NaBH4-MR (methanolysis) and NaBH4-ER (ethanolysis) reactions were carried out at 30, 40, and 50 °C with NaBH4 concentrations of 1.25%, 2.5%, and 5%. Hydrolysis reactions (NaBH4-HR) were conducted at 0.1 M under the same conditions. In the ethanolysis and methanolysis reactions at 30 °C, total hydrogen conversion was achieved at 0.3 M, 0.4 M, and 0.5 M. However, in the hydrolysis reactions, total hydrogen production was only obtained at 50 °C. It was observed that in the NaBH4-MR and NaBH4-ER reactions, total hydrogen conversion could be achieved within 4–5 s. The utilization of adipic acid as a catalyst for hydrogen production from NaBH4 through ethanolysis and methanolysis reactions is proposed as a highly efficient and fast method, characterized by impressive conversion rates.

Two ethanol-solvated adipate and succinate salts of carvedilol (CVD), a Biopharmaceutics Classification System class 2 drug, were synthesized by crystallizing ethanol with adipic acid (ADP) and succinic acid (SUA). Proton transfer from ADP and SUA to CVD and the presence of ethanol in the two novel compounds were confirmed using powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and single-crystal X-ray diffraction measurements. The two novel ethanol-solvated salts exhibited enhanced solubility and dissolution rates compared with pure carvedilol in phosphate buffer (pH 6.8). Additionally, the morphologies and attachment energies of the two novel compounds and pure CVD were calculated based on their single-crystal structures, revealing a correlation between attachment energy and dissolution rate.

Poly (butylene adipate-co-terephthalate) (PBAT) has been extensively used in every field of life, but the PBAT hydrolyzing microorganisms had rarely been studied. In this project, the synergistic degradation effect of bacteria identified from the farm soil of Shaanxi village yuan Jia cun was studied. To improve the degradation of PBAT, a co-culture system was made using SUST B1, SUST B2, and SUST B3. It was noted that the synergistic degradation of PBAT days was greater as compared to the monoculture system. Maximum lipase activity was observed after 6 days of incubation, the lipase activity (24.3 U/mL) of the co-culture surpassed the monoculture which was substantially complex as compared to individual bacterium SUST B1 (9.42 U/mL), SUST B2 (10.1 U/mL), and SUST B3 (8.7 U/mL) degrading 26.1% of PBAT. These results were further confirmed using XRD, FTIR, and SEM analysis. The mechanism of PBAT degradation was also studied using LC/MS. PBAT degradation is comprised of numerous phases that generate oligomers, dimers, and monomers. The microorganisms secreted the PBAT-degrading lipase that catalyzes the ester bonds present in the PBAT backbone and convert it into respective monomers like terephthalic acid, 1, 4-butanediol, and adipic acid. Microbes then uptake them to fulfill their carbon need and degrade them. Hence, PBAT bioremediation can be accomplished by a co-culture system. This is the first study to report the synergistic degradation of PBAT in the co-culture system. [ABSTRACT FROM AUTHOR]