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Membrane Technology for Green Engineering
Published in Neha Kanwar Rawat, Tatiana G. Volova, A. K. Haghi, Applied Biopolymer Technology and Bioplastics, 2021
Supriya Dhume, Yogesh Chendake
The reaction between carboxylic acid and alcohol is understood because the Fischer esterification. It is one amongst the foremost vital reactions of carboxylic acids. Most carboxylic acids are appropriate for the reaction; however, the alcohol ought to usually be a primary or secondary alkyl. Tertiary alcohols are liable to elimination. Once an acid and an alcohol are mixed along, no reaction takes place. However, upon addition of chemical action amounts of an acid, the two components are mix with equilibrium method to contribute an ester and water. The presence of the acid catalyst within the mechanism of ester formation helps in two ways: It causes the carbonyl perform (makes the carbonyl carbon a lot of electrophilic) to bear nucleophilic attack by the alcohol; and protonation of the hydroxyl group offers water, that could be a superior leaving group (i.e., weaker base) within the elimination step. Ordinarily used catalysts for a Fischer esterification sulfuric acid, p-toluenesulfonic acid, and Lewis acids.
Synthesis, X-ray structures, and biological activity of Zn(II) and cd(II) complexes with pyridine thiazolone derivatives
Published in Journal of Coordination Chemistry, 2021
Xunzhong Zou, Yanzhi Liao, Chaojie Yang, Ansheng Feng, Xiaoyun Xu, Huifeng Jiang, Yu Li
2-[4-(2-Pyridinyl)-2-thiazolyl]hydrazone (L1) and 2-[4-(3-pyridinyl)-2-thiazolyl]hydrazone (L2) were prepared according to previously reported literature [7]. Zinc p-toluenesulfonate hydrate and zinc hexafluorosilicate hydrate were purchased from Adama Reagent Co. Ltd. Cadmium p-toluenesulfonate hydrate was prepared by the reaction of p-toluenesulfonic acid and cadmium oxide. All other reagents and solvents were commercially available and employed as received or purified by standard methods prior to use. Four human cancer cell lines were kindly provided by Stem Cell Bank, Chinese Academy of Sciences. Elemental analyses were performed on a Vario EL analyzer (Elementar) and IR spectra on an Avatrar 330 FT-IR spectrometer (Thermo Nicolet) with potassium bromide pellets. The fluorescence (FL) spectra were collected on a Shimadzu RF5301PC photoluminescence spectrometer at room temperature. 1H NMR spectra were determined using a Bruker AVANCE-III 500. Biological activity tests were performed on a SpectraMax® ABS Absorbance Reader (Molecular Devices).
An environmentally benign, simple and proficient synthesis of quinoline derivatives catalyzed by FeCl3.6H2O as a green and readily available catalyst
Published in Green Chemistry Letters and Reviews, 2021
S. Tasqeeruddin, Yahya I. Asiri, S. Shaheen
We then continued to optimize the model reaction (Scheme 1) by detecting the efficiency of the catalyst FeCl3.6H2O and water as a solvent with other reaction conditions. Initially the reaction was carried out in the absence of solvent and catalyst. However, after 28 h at room temperature (rt), no product had been formed (Table 2, entry 1). When the same model reaction was conducted with different catalysts and solvents such as MgO/Ethanol, MgSO4/Ethanol, P-toluenesulfonic acid/Tetrahydrofuran, P-toluenesulfonic acid/Toluene, Pyridinium p-toluene sulfonate/Ethanol, and Pyridinium p-toluene sulfonate/Glycerol (Table 2, entries 2, 3, 4, 5, 6, and 7), the completion of reaction took a longer time. The reaction was also carried out in Triethanolamine/Pyridinium acetate and PEG-600/Pyridinium acetate (Table 2, entries 8 and 9), again only trace amount of the desired product (3a) was obtained. We also examined the model reaction with the reported method procedures which resulted in lower yields of the product 3a (Table 2, entries 10,11, and 12). Therefore, the best results were obtained from FeCl3.6H2O (10 mol%) in water as a solvent at room temperature (Table 2 entry 13).
An antibacterial dental light-cured glass-ionomer cement with improved hardness
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Yong Chen, Gulsah Caneli, Rashed Almousa, Xin Wen, Gregory G. Anderson, Dong Xie
The synthesis was conducted by three steps: (1) Formation of 4-arm star chain-transfer agent [48]. Briefly, to a solution containing pentaerythritol (0.0815 mol) and mercaptoacetic acid (0.4885 mol) in toluene, p-toluenesulfonic acid monohydrate (7.88 mmol) in toluene was added. After refluxing for 3 h, the mixture was poured into saturated sodium bicarbonate solution followed by extracting with ethyl acetate. After washing with 10% hydrochloric acid and saturated sodium chloride solution, the extract was dried with anhydrous magnesium sulfate. The final product was obtained by completely removing ethyl acetate. (2) Synthesis of 4-star poly(acrylic acid-co-itaconic acid). Briefly, to a mixture of acrylic acid (0.072 mol), itaconic acid (0.018 mol) and 2,2′-azobisisobutyronitrile (0.09 mmol) in distilled water, 4-arm star chain-transfer agent (0.503 mmol) in distilled water was added. After nitrogen purging for 10 min, the solution was heated to 70 °C and kept at that temperature for 10 h. The molar feed ratio (acrylic acid:itaconic acid = 8:2 by mole) was used as suggested in our previous publication [9]. (3) Synthesis of photocurable poly(acrylic acid-co-itaconic acid) [49]. Briefly, the 4-arm star-shaped polymer was reacted with glycidyl methacrylate (50 mol% of carboxylic acid) in N,N-dimethylformamide at 50 °C overnight in the presence of pyridine (1% by weight). The methacrylate-tethered polymer was then recovered by precipitation from diethyl ether, followed by drying in vacuo at room temperature. The synthesis scheme is also shown in Figure 1.