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卤素交换氟化反应是合成含氟芳香化合物的重要方法之一,相转移催化剂对卤素交换氟化反应来说几乎是不可或缺的。本文以对叔丁基杯[4]芳烃和四甘醇二对甲苯磺酸酯为原料,在K2CO3存在下,合成了对叔丁基杯[4]-冠-5,将对叔丁基杯[4]-冠-5作为相转移催化剂应用于对氯硝基苯的氟化反应中,以检测其作为相转移催化剂在氟化反应中的催化活性,同时考察了反应时间、反应温度、不同相转移催化剂对卤素交换氟化反应的影响。结果表明对叔丁基杯[4]-冠-5对氟化反应具有相转移催化能力,研究发现以杯芳冠醚作相转移催化剂,使产品收率得到了明显提高。在对叔丁基杯[4]-冠-5的催化下,反应3h,反应的转化率和收率分别为96.53%、90.8%。 相似文献
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从反应原理、催化剂的选择、副反应的发生与控制等方面综述了芳香硝基化合物直接氟化的研究进展,阐述了硝基氟化的意义及应用重要性,介绍了硝基氟化的最新研究与发展方向。 相似文献
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季鏻盐相转移催化卡宾法合成医药中间体(±)-α-氨基苯乙酸 总被引:1,自引:0,他引:1
在自制的四种季盐相转移催化剂和氯化锂的催化作用下 ,由苯甲醛 ,氯仿和氨合成了医药中间体 (± ) - α-氨基苯乙酸 ,研究了催化剂的催化性能 ,选择了较佳的催化剂和合成反应的较佳条件。结果表明 ,在苯甲醛和催化剂的摩比为 1∶ 1 ;氯化锂与苯甲醛的摩尔比为 2∶ 1 ;反应温度控制在 0~ - 1 5°C之间 ;反应时间 4h的条件下 ,(± ) - α-氨基苯乙酸其化学产率达 72 %。该合成法具有收率较高且避免了 Strecker合成法使用高毒性原料的特点 ,反应条件较易达到。其存在的不足是催化剂不易分离 ,不能反复利用。提出了解决该问题的途径之一是采用“三相转移催化剂”。 相似文献
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2,3,4,5-四氟苯甲酸的制备 总被引:2,自引:0,他引:2
以四氯邻苯二甲酸酐为原料,经酰亚胺化、氟化、水解和脱羧4步反应合成四氟苯甲酸。研究了相转移催化剂对酰胺化反应、氟化反应的影响以及表面活性剂对水解反应的影响。结果表明,酰亚胺化反应中,采用相转移催化法缩短了反应时间,收率达97.3%;氟化反应中采用杯芳烃作为相转移催化剂,收率达81.2%;水解反应中加入表面活性剂十二烷基苯磺酸钠使反应时间大大缩短,其收率达91%。经过改进,反应总时间由56h缩短至11h,总收率由47、3%提高到64.3%。 相似文献
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The synthesis and characterization of 27 novel polystyrene resin-supported optically active phase transfer catalysts is described. The first group of five catalytic species are essentially supported tetraethylene oxide derivatives each carrying a terminal chiral group. The second group consists of resins loaded with a protected galactose function along with a range of onium salt and oligoether catalysts. The third group are analogous to the second with a protected fructose residue replacing the galactose one. In the fourth group some attempt has been made to define the stereochemical relationship between the chiral species and the catalytic one, by attaching a chiral diphosphine to the support. Similarly, a phosphinated sugar, ephedrine and quinine have been attached. In the final group a chiral acetal function has been synthesized on the resin, and this function subsequently modified with a phosphonium salt and an oligoether each as the phase transfer catalytic species. In general good loadings were achieved as indicated by changes in elemental analyses and shifts in the infra-red absorption spectra of resins. 相似文献
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A novel synthesis of polyphosphates by inverse phase transfer catalysis (IPTC) was investigated. The reaction of methylphosphoric dichloride (MPD) and sodium salt of bisphenol A (BA) in two-phase H2O/CH2Cl2 medium under IPTC is presented and the results are evaluated by the yield and inherent viscosity values. The biphasic medium does not require rigorous stirring. The polyphosphate was characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Pyridine (Py), pyridine-oxide (PNO) and 4-dimethylamino-pyridine (DMAP) were used as the inverse phase transfer catalysts. DMAP was found to be the best catalyst. 相似文献