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Currently, amidst atmospheric menace where natural calamities such as wildfire and floods are becoming more frequent than ever, biobased derivatives offer a sustainable alternative to conventional ways, for instance, petrochemical commodities. Biobased products, obtained from agricultural waste, including 5-(hydroxymethyl)furfural (HMF), 2,5-bis(hydroxymethyl)furan (BHMF), and 2,5-furandicarboxylic acid (FDCA) are promising chemical platforms in the biorefinery, which is yet to be explored. The Diels-Alder cycloaddition of BHMF and N -phenylmaleimide derivatives under optimal reaction conditions is investigated in this report. First, HMF is reduced to BHMF in the presence of NaBH 4 , and then the Diels-Alder reaction of BHMF and N -phenylmaleimide derivatives is investigated to produce Diels-Alder adducts. All novel compounds are synthesized in acceptable yields and effectively characterized by employing important techniques such as one-dimensional (1D) NMR spectroscopy ( 1 H, 13 C, DEPT-90, and DEPT- 135), two-dimensional (2D) NMR spectroscopy ( 1 H- 1 H COSY, 1 H- 13 C HSQC, and 1 H- 13 C HMBC), IR spectroscopy, elemental analysis, mass spectrum (QTOF), and single-crystal X-ray diffraction (SC-XRD). Furthermore, this study underlines the necessity of sustainable synthetic methodologies and gives critical insights into the progress of ecologically friendly methodologies, providing a new avenue as a tunable precursor for the challenging functionalized polymer in the future., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Poly(ethylene terephthalate) (PET) is the most common plastics produced for applications in food and drinking containers. It is degraded to valuable product by several methods. Glycolysis of PET gains bis (2-hydroxyethylene) terephthalate (BHET) as the main product utilized as plasticizer. Calcium catalysts, Ca 2+ and Ca(OH) 2 ∙2H 2 O were explored to study the mechanism of PET cleavage by DFT calculations at B3LYP/6-311++G** level. Two possible pathways, coordination, and non-coordination of ethylene glycol on the calcium in glycolysis reaction, have been investigated. In addition, poly(ethylene furanoate) (PEF), considered as a sustainable polymer with the similar functional properties, was chose for the comparison of conformational structures with PET. The understanding of the relationship between PET (and PEF) structures and calcium catalysts is useful for the future development of linear sustainable polyesters., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Ekasith Somsook reports financial support was provided by 10.13039/501100004156Mahidol University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The promising influences of K + and Ca 2+ ions in the development of effective MnO 2 for the selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid (FDCA) were studied for the catalytic performance under a high-pressure reaction of aqueous O 2 (0.5 MPa) in a basic system. Various oxidation states of manganese in MnO 2 were able to accelerate the oxidation of 5-formyl-2-furancarboxylic acid to FDCA in the rate-determining step. The results were in good agreement that Ca 2+ played a key role in the highest FDCA yield up to 85% due to the associated cations on the local coordination to enhance the high surface area and the electronic effect on the manganese ion. Both K-MnO 2 and Ca-MnO 2 catalysts showed excellent catalytic activities without a significant change in the efficiency in the reusability experiments., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The development of adsorption technology and the processing of radiation have both been influenced by chitosan adsorbent (γ-chitosan), a raw material with unique features. The goal of the current work was to improve the synthesis of Fe-SBA-15 utilizing chitosan that has undergone gamma radiation (Fe-γ-CS-SBA-15) in order to investigate the removal of methylene blue dye in a single hydrothermal procedure. High-resolution transmission electron microscopy (HRTEM), High angle annular dark field scanning transmission electron microscopy (HAADF-STEM), small- and wide-angle X-ray powder diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR) and Energydispersive X-ray spectroscopy (EDS) were used to characterize γ-CS-SBA-15 that had been exposed to Fe. By using N 2 -physisorption (BET, BJH), the structure of Fe-γ-CS-SBA-15 was investigated. The study parameters also included the effect of solution pH, adsorbent dose and contact time on the methylene blue adsorption. The elimination efficiency of the methylene blue dye was compiled using a UV-VIS spectrophotometer. The results of the characterization show that the Fe-γ-CS-SBA-15 has a substantial pore volume of 504 m 2  g -1 and a surface area of 0.88 cm 3  g -1 . Furthermore, the maximum adsorption capacity (Q max ) of the methylene blue is 176.70 mg/g. The γ-CS can make SBA-15 operate better. It proves that the distribution of Fe and chitosan (the C and N components) in SBA-15 channels is uniform., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (© 2023 The Authors.)

[L C R P((PhP) 2 C 2 H 4 )][OTf] (4 a,b[OTf]) and [L C iPr P(PPh 2 ) 2 ][OTf] (5 b[OTf]) were prepared from the reaction of imidazoliumyl-substituted dipyrazolylphosphane triflate salts [L C R P(pyr) 2 ][OTf] (3 a,b[OTf]; a: R=Me, b=iPr; L C R =1,3-dialkyl-4,5-dimethylimidazol-2-yl; pyr=3,5-dimethylpyrazol-1-yl) with the secondary phosphanes PhP(H)C 2 H 4 P(H)Ph) and Ph 2 PH. A stepwise double P-N/P-P bond metathesis to catena-tetraphosphane-2,3-diium triflate salt [(Ph 2 P) 2 (L C Me P) 2 ][OTf] 2 (7 a[OTf] 2 ) is observed when reacting 3 a[OTf] with diphosphane P 2 Ph 4 . The coordination ability of 5 b[OTf] was probed with selected coinage metal salts [Cu(CH 3 CN) 4 ]OTf, AgOTf and AuCl(tht) (tht=tetrahydrothiophene). For AuCl(tht), the helical complex [{(Ph 2 PPL C iPr )Au} 4 ][OTf] 4 (9[OTf] 4 ) was unexpectedly formed as a result of a chloride-induced P-P bond cleavage. The weakly coordinating triflate anion enables the formation of the expected copper(I) and silver(I) complexes [(5 b)M(CH 3 CN) 3 ][OTf] 2 (M=Cu, Ag) (10[OTf] 2 , 11[OTf] 2 )., (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Polycystic ovarian syndrome (PCOS) is a common and complex condition characterized by endocrine features and influenced by genetic and environmental factors. In Southeast Asia and Thailand, the prevalence of PCOS is unknown. The aim of this study was to estimate the prevalence of and determine factors associated with PCOS in Thai adolescents. We administered a validated questionnaire to 600 university female participants aged 17-19 years from Mahidol University in Bangkok. Of these, 548 (91.33%) responded and agreed to participate. Two-hundred and seventy-nine girls (50.91%) were identified as likely having PCOS and defined as 'probable cases'. Of those 279 participants, 248 (88.88%) were evaluated further for PCOS using the Rotterdam criteria. A complete history was taken, and a physical examination including trans-abdominal ultrasound was performed. Blood chemistry tests were performed to exclude similar conditions and to investigate potential co-morbidities. The prevalence of PCOS in Thai adolescents was found to be 5.29%. After multivariate analyses, moderate acne was the strongest risk factor for PCOS. The odd ratios (95% confidence interval) for the presence of mild acne, moderate acne, and oligo- or amenorrhea in participants with PCOS were 2.83 (1.01-7.90; p = .47), 31.69 (10.07-99.67; p < .001), and 5.89 (2.42-14.37; p < .001), respectively.

A new method for utilization of hydrogel is proposed here for the preparation of solid base catalysts for the transesterification of vegetable oil. When a solution of KF is mixed with a solution of Ca(NO 3 ) 2 , CaF 2 is obtained and inactive as a catalyst in the transesterification of vegetable oils. The catalysts were synthesized by the sequential incorporation of KF and/or Ca(NO 3 ) 2 solutions into the hydrogel upon microwave irradiation and then the as-obtained hydrogel was calcined at 800°C for 5 hours to eliminate the template and yield catalysts for the biodiesel productions. The prepared catalysts obtained by the different ways in the incorporation of ions into the hydrogel showed different physical properties and catalytic activities in the transesterification of soybean oil. All catalysts, except the low concentration of Ca(NO 3 ) 2 , exhibiting the high activity yielding more than 90% FAME after 1 hour at 65°C, using oil to methanol molar ratio of 1:15 and 10 wt% of catalyst amounts.

Iron oxide nanoparticles were used as supporters for in situ polymerization to produce polymer nanocomposites with well-dispersed fillers in polymer matrix. Iron oxide could be sustained as colloidal solutions by cassava starch to produce a good dispersion of iron oxide in the matrix. New supports based on iron oxide/cassava starch or cassava starch for Ziegler-Natta catalysts were utilized as heterogeneous supporters for partially hydrolyzed triethylaluminum. Then, TiCl4 was immobilized on the supports as catalysts for polymerization of ethylene. High-density polyethylene (HDPE) composites were obtained by the synthesized catalysts. A good dispersion of iron oxide/cassava starch particles was observed in the synthesized polymer matrix promoting to good mechanical properties of HDPE., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The strong inhibitor effect of aryl iodides on the quasi-homogenous gold-catalyzed oxidation reaction was described. Aryl iodides were adsorbed on the exposed surface of Au clusters, which affected the accessibility of the nanoclusters to the reacting species and acted as strong inhibitors in catalysis.

Propylsulfonic acid-functionalized mesoporous silica SBA-15 has been synthesized via one-step strategy at 130°C based on the co-condensation of TEOS and MPTMS in the presence of Pluronic 123 polymer and H₂O₂ in HCl aqueous solution. The synthesized solid exhibited hydrothermal stability in boiling water without significant change in textural properties. The catalytic performance of the synthesized solid was studied in the esterification of oleic acid with methanol. The experimental results revealed that the large mesopore structures of SBA-15-PrSO₃H solid synthesized at 130°C could favor a facile access of oleic acid to the acid sites, making the comparable activity to that of phenyl ethyl sulfonic acid functionalized silica and higher than that of dry amberlyst-15.

This paper describes the unique catalytic activity of bimetallic Au/Pd alloy nanoclusters (NCs) for Ullmann coupling of chloroarenes in aqueous media at low temperature. The corresponding reaction cannot be achieved by monometallic Au and Pd NCs as well as their physical mixtures. On the basis of quantum chemical calculation, it was found that the crucial step to govern the unusual catalytic activity of Au/Pd is the dissociative chemisorption of ArCl, which is unlikely in the monometallic Au and Pd NCs.

Novel phthalimide and o-sulfobenzimide-functionalized silsesquioxanes were successfully synthesized via nucleophilic substitution reactions from octakis(3-chloropropyl)octasilsesquioxane. Surprisingly, the formation of deca- and dodecasilsesquioxanes cages was discovered during substitution with phthalimide, but only octasilsesquioxane maintained a cage in the o-sulfobenzimide substitution reaction. Moreover, we report the electronic effect of nitrogen nucleophiles to promote cage-rearrangement of inorganic silsesquioxane core for the first time. Structures of products were confirmed by (1)H, (13)C, and (29)Si NMR spectroscopy, ESI-MS analysis, and single-crystal X-ray diffraction.

A poly(aniline-co-m-ferrocenylaniline) was successfully synthesized on a glassy carbon electrode (GCE) by electrochemical copolymerization using a scan potential range from -0.3 to +0.9 V (vs. Ag/AgCl) in 0.5 M H2SO4 containing 30% acetonitrile (ACN), 0.1 M aniline (Ani) and 0.005 M m-ferrocenyaniline (m-FcAni). The field emission scanning electron microscope (FESEM) and electrochemical methods were used to characterize the poly(Ani-co-m-FcAni) modified electrode. The poly(Ani-co-m-FcAni)/GCE exhibited excellent electrocatalytic oxidation of ascorbic acid (AA) in citrate buffer solution (CBS, pH 5.0). The anodic peak potential of AA was shifted from +0.55 V at the bare GCE to +0.25 V at the poly(Ani-co-m-FcAni)/GCE with higher current responses than those seen on the bare GCE. The scan number at the 10th cycle was selected as the maximum scan cycle in electrochemical polymerization. The limit of detection (LOD) was estimated to be 2.0 μM based on the signal-to-noise ratio (S/N = 3). The amperometric responses demonstrated an excellent selectivity for AA determination over glucose (Glu) and dopamine (DA).

Metallocene-catalyzed polymerization of 1-alkenes offers fine control of critical polymer attributes such as molecular weight, polydispersity, tacticity, and comonomer incorporation. Enormous effort has been expended on the synthesis and discovery of new catalysts and activators, but elementary aspects of the catalytic processes remain unclear. For example, it is unclear how the catalyst is distributed among active and dormant sites and how this distribution influences the order in monomer for the propagation rates, for which widely varying values are reported. Similarly, although empirical relationships between average molecular weights and monomer have been established for many systems, the underlying mechanisms of chain termination are unclear. Another area of intense interest concerns the role of ion-pairing in controlling the activity and termination mechanisms of metallocene-catalyzed polymerizations. Herein we report the application of quenched-flow kinetics, active site counting, polymer microstructure analysis, and molecular weight distribution analysis to the determination of fundamental rate laws for initiation, propagation, and termination for the polymerization of 1-hexene in toluene solution as catalyzed by the contact ion-pair, [rac-(C(2)H(4)(1-indenyl)(2))ZrMe][MeB(C(6)F(5))(3)] (1) over the temperature range of -10 to 50 degrees C. Highly isotactic (>99% mmmm) poly-1-hexene is produced with no apparent enchained regioerrors. Initiation and propagation processes are first order in the concentrations of 1-hexene and 1 but independent of excess borane or the addition of the contact ion-pair [PhNMe(3)][MeB(C(6)F(5))(3)]. Active site counting and the reaction kinetics provide no evidence of catalyst accumulation in dormant or inactive sites. Initiation is slower than propagation by a factor of 70. The principal termination process is the formation of unsaturates of two types: vinylidene end groups that arise from termination after a 1,2 insertion and vinylene end groups that follow 2,1 insertions. The rate law for the former termination process is independent of the 1-hexene concentration, whereas the latter is first order. Analysis of (13)C-labeled polymer provides support for a mechanism of vinylene end group formation that is not chain transfer to monomer. Deterministic modeling of the molecular weight distributions using the fundamental rate laws and kinetic constants demonstrates the robustness of the kinetic analysis. Comparisons of insertion frequencies with estimated limits on the rates of ion-pair symmetrization obtained by NMR suggest that ion-pair separation prior to insertion is not required, but the analysis requires assumptions that cannot be validated.