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乙基麦芽酚的合成工艺研究周建纯朱庆安(珠海金珠应用化学研究所519015)一、前言乙基麦芽酚学名为2—乙基-3-羟基-4H-吡喃酮-[4],英文名称为2-ethyl-3-hydroxy-4h-pyran-4-one,分子式C7H8O3,分子量140.... 相似文献
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研究了α-羟基异丙基苯甲酮及其衍生物的合成工艺,对各单元反应的条件及影响因素等进行了探讨。 相似文献
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以焦性没食子酸为原料,甲醇-水为混合溶剂,草酸-磷酸为催化剂,氮气保护的条件下与三氯甲苯反应,合成了重要的工业材料2,3,4-三羟基二苯酮(3HBP),反应条件温和。通过单因素实验确定了合成3HBP的最适宜工艺条件为:焦性没食子酸的质量为6.3 g(0.05 mol),混合溶剂甲醇-水(体积比为2:8)为50.0 mL,升温至40℃时缓慢滴加三氯甲苯(0.055 mol),滴加完毕后升温至65℃恒温反应至原料焦性没食子酸消失。在最适宜条件合成的3HBP,经柱层析后收率为89.1%。该合成方法简便,环境污染小,绿色环保,具有工业化应用的潜力。 相似文献
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含环己烯结构新型氯代双酮化合物的合成及表征 总被引:4,自引:1,他引:3
本文以顺丁烯二酸酐、氯苯经Friedlle-Crafts反应合成了1,2-二(4-氯苯甲酰基)乙烯。经Diels-Alder反应,以异戊二烯环加成合成了含环乙烯结构的双氯双酮化合物:1-甲基-4,5-二(4-氯苯甲酰基)环己烯。该氯代双酮化合物具有不饱和双键结构,是制备聚芳醚酮功能高分子材料的理想单体。 相似文献
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以DPPH?为研究对象,采用紫外-可见光分光光度计研究了新型分子内复合抗氧剂对自由基的清除能力,并与市售抗氧剂1076和BHT进行对比。结果表明,相同条件下,该新型分子内复合抗氧剂清除自由基的能力优于市售抗氧剂1076和BHT;且清除自由基的能力随抗氧剂浓度的增加而增大,随清除反应时间的延长先增大后趋于稳定。清除反应温度对清除能力影响不大,表明该清除反应的反应活化能较低,该清除反应可在室温下快速进行。熔体流变速率和氧化诱导期测得的结果也证实了新型分子内复合抗氧剂的抗氧化能力优于市售抗氧剂BHT和1076。 相似文献
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为比较黄酮2、3位单双键不同及3'、4'邻位取代基不同对清除自由基活性的影响。采用UV-Vis光谱法测定了木犀草素、香叶木素及橙皮素对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)、超氧阴离子自由基(O2-·)的清除作用。结果显示3种黄酮化合物对两种自由基都有一定的清除作用,清除效果随浓度的增大而增大。但对自由基清除能力表现为木犀草素远强于香叶木素、香叶木素与橙皮素无显著差别。说明具有B环3'、4'邻二羟基结构的黄酮清除自由基的能力明显强于具有B环3'羟基、4'甲氧基结构的黄酮;黄酮C环2、3位单双键不同对自由基清除能力影响不显著。 相似文献
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Haq Nawaz Nadia Zafar Raheela Jabeen Adnan Amjad Mohibullah Shah Saba Munir 《European Journal of Lipid Science and Technology》2023,125(11):2300053
The repeated use of cooking oils and ghee for the deep frying of food materials may affect their nutritional quality. The present study evaluated the effect of repeated frying on the physicochemical characteristics and antiradical potential of canola oil and ghee. The oil and ghee were used for frying of fish and chicken for 2, 4, 6, 8, and 10 frying cycles followed by the analysis of physicochemical, oxidative stress, and antiradical parameters. Regression analysis of the data showed a frying cycle-dependent significant linear increase in saponification (R2 = 0.9507–0.9748), peroxide and acid values (R2 = 0.956–0.9915), and malondialdehyde (MDA) production (R2 = 0.9058–0.9557) of canola oil and ghee subjected to fish and chicken frying but exponential increase in saponification value (R2 = 0.9778) and MDA production (R2 = 0.7407) of canola oil and ghee used for fish frying. The increase in the number of frying cycles linearly decreased the iodine value (R2 = 0.9781–0.9924), and 1, 1-diphenyl-2-picrylhydrazyl, hydroxyl, and 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging potential (R2 = 0.9089–0.9979) of canola oil and ghee. Repeated frying in cooking oil and ghee increases oxidative stress and decreases their physicochemical and antioxidant qualities. Canola oil was comparatively more oxidative resistant than canola ghee. The regression equations derived from regression analysis will guide researchers to conduct similar types of univariate studies. 相似文献
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Living free radical polymerizations are employed to synthesize the polystyrene copolymer. The applications of those copolymer in nanomaterials are elucidated in this research. It involves the copolymerization of styrene with 2‐hydroxyethyl methacrylate. The copolymers are reacted with cinnamoyl chloride, and then irradiated with UV light. The polymeric nanofibers are formed by solvent splitting. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3550–3558, 2006 相似文献
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《Reactive and Functional Polymers》2012,72(11):807-813
Solid phase radical scavengers have been prepared by the immobilization of antioxidant (AOX) compounds on macroporous polymers. Poly(glycidylmethacrylate-co-trimethylolpropane trimethacrylate) [poly(GMA–TRIM)] and poly(N-acryloyl-tris(hydroxymethyl)aminomethane-co-glycidylmethacrylate-co-N,N′-methylenebisacrylamide) [poly(NAT–GMA–BIS)] were prepared by free radical polymerization using a mixture of dimethylsulfoxide (DMSO)-poly(ethyleneglycol) 6000 (PEG 6000) as a porogenic solvent. The polymers were aminated with ethylenediamine (EDA) and the linkage of the polyphenolic compounds (gallic and caffeic acids) was carried out by two different approaches: through N,N′-dicyclohexylcarbodiimide/4-dimethylaminepyridine (DCC/DMAP) system (one-step method) or through the previous formation of the acyl chloride of the polyphenolic compounds and subsequent amidation reaction (two-step method). The available phenolic groups on the macroporous polymers were determined using the Folin–Ciocalteu method; the radical scavenging properties of the materials prepared were evaluated using the radical species 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid] radical cation (ABTS+). From the results, higher antiradical capacities were obtained with the polymers in which the immobilization of the antioxidant molecules was performed through the two-step method. The polymeric networks prepared in this work yielded up to 13.2 μmol AOX/g of dry polymer, which allowed a quantitative removal of the radicals tested in less than 30 min. 相似文献
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Thermosensitive gel is synthesized through controlled/“living” free radical copolymerization of styrene and DVB mediated by an alkoxyamine inimer, 2,2,6,6-tetramethyl-1-(1′-phenylethoxy)-4-(4′-vinylbenzyloxy)-piperidine (V-ET). The inimer plays the role of both incorporating “T-shaped” inter-chain linkages and mediating the polymerization. First order kinetics is observed for crosslinking polymerizations before gel point, indicating a constant concentration of propagating radicals. Monomer conversion at the gel point depends on the feed ratio of DVB to V-ET. Higher amount of V-ET results in later gel point due to smaller molecular weight of the primary chains that depends inversely on the concentration of nitroxide. The resulting gel contains permanent and labile crosslinking points formed by DVB units and alkoxyamine moieties, respectively. Therefore, the gels exhibit gel-sol transition within a narrow temperature range. The gel properties, such as the swelling ratio and gel-sol transition temperature, can be controlled by changing the feed ratio of DVB to V-ET. The microenvironments in different gels, or at different temperatures, are investigated by ESR spectroscopy. 相似文献
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Partially N‐acetylated chitosan was hydrolyzed by the cheap, commercially available, and efficient cellulase. The products, with different molecular weight, were comparatively investigated by GPC, FT‐IR, XRD, and NMR. The results show that the decrease of molecular weight led to transformation of crystal structure and increase of water‐solubility, but the chemical structures of residues were not modified. Superoxide anion radical and hydroxyl radical quenching assay were used for the evaluation of free radical scavenging activity of cellulase‐treated chitosan in vitro. Low molecular weight chitosan (LMWC3, Mw 1.7 × 103) exhibited high scavenging activity against free radical. It scavenged 79.3% superoxide radical at 0.1 mg mL?1. At 2.0 mg mL?1, scavenging percentage of initial chitiosan, LMWC1 (Mw 27.3 × 103), LMWC2 (Mw 5.9 × 103), and LMWC3 (Mw 1.7 × 103) against hydroxyl radical was 14.3%, 33.1%, 47.4%, and 65.9%, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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A novel free radical interfacial copolymerization was proposed and used to prepare the amphiphilic block copolymer of acrylamide (AM) with styrene (S). In this copolymerization, a synthesized new kind of initiator, namely, amphiphilic bifunctional initiator, which has not only a hydrophilic and a hydrophobic group but also two functional groups generating radicals in both ends of its molecule, was used to initiate the interfacial copolymerization. The generated amphiphilic block copolymer was characterized by infrared analysis, differential scanning calorimetry, elemental analysis, and dissolution behavior. The migration of generated copolymer from interface to water phase was discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 443–449, 1998 相似文献