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生物质转化合成新能源化学品乙酰丙酸酯 总被引:2,自引:0,他引:2
生物质是唯一可替代化石资源获取液态燃料和化学品的可再生资源,近年来由生物质转化合成乙酰丙酸酯引起了研究者们越来越广泛的关注。乙酰丙酸酯是一类重要的化学中间体和新能源化学品,具有高的反应特性和广泛的工业应用价值。目前开发的从生物质资源出发转化合成乙酰丙酸酯的潜在合成途径可概括为4种:直接酸催化醇解法、经乙酰丙酸酯化、经5-氯甲基糠醛醇解和经糠醇醇解。本文分别介绍了这4种转化合成途径的化学反应过程及最新研究进展,从反应合成工艺、催化体系、经济可行性等方面评述了各自的特点与发展趋势,并分析了目前工业规模转化生物质合成乙酰丙酸酯仍面临的一些科学难点。最后,对今后该领域的研究前景进行了展望。 相似文献
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混合溶剂中酶促合成维生素A乳酸酯 总被引:1,自引:0,他引:1
研究了混合溶剂中脂肪酶催化合成维生素A乳酸酯.首先对催化合成维生素A乳酸酯反应的脂肪酶和反应介质进行了研究,其次对影响合成维生素A乳酸酯反应的因素(温度、底物摩尔比、反应时间和酶量等)进行了探讨,优化了反应条件:在5 mL混合溶剂(叔丁醇/正己烷(v/v)=3:2)中,0.167 g维生素A醋酸酯和0.150g乳酸在25 mg脂肪酶Novozym 435催化下,在35℃、150 r/m in下反应6 h,产率可以达到52.19%,固定化酶可连续使用5次以上,产率仍达45%以上. 相似文献
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众所周知,酯是重要的精细化工产品。有些酯可作水果香精,有些酯是高级酒香的重要成分,己二酸二辛酯和癸二酸二辛酯则是高级增塑剂。通常,酯是用羧酸和醇反应制得。若能利用来自石油化工厂的烯烃和CO代替得之不易的羧酸来生产酯类。将具有明显的实际意义。国外曾试探过许多过渡金属包括钴、铑、铱等的配位催化体系对烯烃进行氢酯基化的催化反应,其中以钯膦体系效果最佳。国内,已有二、三个研究小组对钯膦体系进行探索,但未见有关钯膦酸催化剂体系方面的报道。本文介绍我们在钯膦酸体系催化氢酯基化反应的一些实验结果。 相似文献
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Minghao Zhang Zhiyang Ye Prof. Dr. Wanxiang Zhao 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306248
Enantioselective functionalization of racemic alkyl halides is an efficient strategy to assemble complex chiral molecules, but remains one of the biggest challenges in organic chemistry. The distant and selective activation of unreactive C−H bonds in alkyl halides has received growing interest as it enables rapid generation of molecular complexity from simple building blocks. Here, we reported a cobalt-catalyzed remote borylation of alkyl (pseudo)halides (alkyl−X, X=I, Br, Cl, OTs) with pinacolborane (HBpin) and presented a robust approach for the generation of valuable chiral secondary organoboronates from racemic alkyl halides. This migration borylation reaction is compatible with primary, secondary, and tertiary bromides, offering direct access to a broad range of alkylboronates. The extension of this catalytic system to the borylation of aryl halides was also demonstrated. Preliminary mechanistic studies revealed that this remote borylation involved a radical reaction pathway. 相似文献
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Wanida Munbunjong Poonlarp Ngernmaneerat Sung Jun Kim Warinthorn Chavasiri Doo Ok Jang 《Tetrahedron》2009,65(12):2467-4055
A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine. 相似文献
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Rate constants directly measured from GC-analyzed method for SmI2 reduction of alkyl halides were obtained. The rates increase in the orders of primary, secondary, tertiary RX and RCl < RBr < RI as expected. 2-Heptanone was chosen as the partner of alkyl halide in the samarium Barbier reaction. In the absence of HMPA, the reaction orders of alkyl halide and ketone were determined as first and zero order, respectively. 相似文献
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不同链长烷基芳基磺酸盐形成微乳液的性质 总被引:1,自引:0,他引:1
以Winsor相态图法和拟三元相图法研究了自制的3种不同链长烷基芳基磺酸盐在多组分体系中形成的微乳液的性质, 并考察了分子结构、无机盐和短链醇等的影响. 结果表明, 无机盐浓度的增加导致表面活性剂/正丁醇/正辛烷/NaCl/水形成的微乳液体系在一定温度下发生由WinsorⅠ→ WinsorⅢ→ WinsorⅡ型转变; 随着烷基芳基磺酸盐分子的长烷基链碳原子数的增加, 耐盐能力减弱, 增溶能力提高; 随着醇碳链的增大, 微乳区面积先增大后减小. 当烷基芳基磺酸盐分子结构固定时, 最大微乳液区域醇的选择依据符合Bansal理论. 醇的链长一定时, 随着烷基芳基磺酸盐分子的长烷基链碳原子数的增加, 微乳液的区域变小. 相似文献
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A Structure–Activity Study of Nickel NNN Pincer Complexes for Alkyl‐Alkyl Kumada and Suzuki–Miyaura Coupling Reactions
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Thomas Di Franco Marko Stojanovic Sébastien Carlos Keller Rosario Scopelliti Xile Hu 《Helvetica chimica acta》2016,99(11):830-847
A new series of Ni NNN pincer complexes were synthesized and characterized. The main difference among these complexes is the substituents on the side arm amino group(s). No major structural difference was found except for the C–N–C angle of the various substituents and the ‘pseudo bite angle’ of the complexes. Four new complexes were efficient for the alkyl‐alkyl Kumada reaction of primary alkyl halides, and among them, one complex was also efficient with secondary alkyl halides. The influence of the substituents on the catalytic performance of the Ni complexes in alkyl‐alkyl Kumada and Suzuki–Miyaura cross‐coupling reactions was systematically investigated. No correlation was found between the catalytic activity and the key structural parameters (C–N–C angle and ‘pseudo bite angle’), redox properties or Lewis acidity of the complexes. 相似文献
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JinLingCHAI ShouQingWANG GanZuoLI QingXU YanHongGAO 《中国化学快报》2004,15(6):699-702
A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol,catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol/cyclohexane/phosphate buffer solution. The restult shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0,the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams. 相似文献
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Wen Zhang 《Tetrahedron》2006,62(37):8715-8719
The reductive coupling of acyl cyanides promoted by alkyl phosphines has been discovered. Under mild reaction conditions, the substituted cyanohydrins were obtained in moderate to high yields by using trimethylphosphine or tributylphosphine as a promoter. The possible mechanism involved in the reaction was discussed on the basis of deuterium labeling and control experiments, indicating that one hydride transfer took place from alkyl phosphine to O-acyl cyanohydrin. 相似文献
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Electrochemical bromination of alkyl aromatic compounds by two-phase electrolysis yields the corresponding α, α-dibrominated products. The reaction has been carried out in a single-compartment electrochemical cell using aqueous sodium bromide (40–50%), containing a catalytic amount of HBr as electrolyte, and chloroform, containing an alkyl aromatic compound, as the organic phase with a Pt plate as anode at 10–15°C. Two-phase electrolysis results in high yields (70–90%) of dibromomethyl, bis(bromomethyl), and bis(dibromomethyl) arenes, depending upon the charge passed. 相似文献