Mechanism of solid-liquid phase transfer catalysis by polymer-supported linear polyethers

Polystyrene resin-supported oligo-oxyethylenes have been used as catalysts in the reaction of solid potassium phenoxide with 1-bromobutane in toluene. Detailed kinetic analysis has established the rate law to be similar in form to that found for catalysis by a non-supported polyether, and activation energies also to be similar. In each case the rate controlling process appears to be the reaction of the catalyst/salt complex with the alkyl halide. The various possible mechanisms by which phase transfer of the salt into the resin-bound catalyst takes place are discussed, and collisional contact between the resin and the solid salt shown to be a prerequisite for efficient catalysis.     

相转移催化法制备乙酸大茴香酯的研究

本研究以乙酸钠为亲核取代试剂．在相转移催化剂的作用下,将对甲氧基苄氯转变为乙酸大茴香酯．考察了各种因素对相转移催化反应的影响规律．探讨了相转移催化反应的机理。结果表明,相转移催化剂能将乙酸负离子（CH3COO）从水相中转移至油相中．与对甲氧基苄氯发生亲核取代．高产率地制得了乙酸大茴香酯。     

用四丁基溴化铵相转移催化合成α-取代芳香乙腈

芳香乙腈与卤代烃在50%NaOH溶液中经(Bu-t)4NBr相转移催化,合成了一系列α-取代芳香乙腈,产物结构通过IR、1HNMR、元素分析确证.这是一种无有机溶剂的绿色反应.     

Preparation of diphenyl acetonitrile by phase transfer catalysis

Preparation of diphenyl acetonitrile has been investigated by the reaction of diphenyl methyl bromide with aqueous sodium cyanide, using quaternary ammonium salts as phase transfer catalysts. The effect of catalyst, temperature, catalyst loading, and reactant concentration on the conversion of diphenyl methyl bromide to diphenyl acetonitrile has been studied. Suitable process conditions have been established for the production of diphenyl acetonitrile.     

相转移催化合成甲基丙烯酸烯丙酯

采用3-氯丙烯和甲基丙烯酸钠为原料,以溴化十六烷基三甲基铵为相转移催化剂,合成了甲基丙烯酸烯丙酯。产物经红外光谱、核磁共振氢谱和质谱表征。考察了反应溶剂、原料摩尔比、催化剂用量、反应温度和反应时间对反应收率的影响。当甲基丙烯酸钠和3-氯丙烯的摩尔比为1∶2.5,催化剂和对苯醌阻聚剂用量分别为甲基丙烯酸钠质量的3%和0.5%,以二甲亚砜为反应溶剂且其体积用量为3-氯丙烯体积的2.25倍时,于50℃搅拌反应3 h,可使甲基丙烯酸烯丙酯摩尔收率达到85%。     

相转移催化法合成1,4-二丁氧基苯

以水为溶剂,在相转移催化剂四丁基溴化铵和氢氧化钾存在的条件下,对苯二酚和溴代正丁烷反应合成了1,4-二丁氧基苯。通过对水的用量、相转移催化剂种类及用量和反应时间的考察,得出了较适宜的合成条件:对苯二酚0.1 mol,溴代正丁烷0.21 mol,氢氧化钾0.21 mol,水10 mL,相转移催化剂四丁基溴化铵用量为1.5 mmol,反应时间4 h,所得产率可达94%。     

相转移催化合成对甲苯苄醚

在相转移催化剂存在下，以对甲苯酚、氯化苄为原料合成对甲苯苄醚，研究了反应温度、反应时间、原料配比和催化剂用量等条件对合成反应的影响，确定了较佳工艺条件。该方法合成对甲苯苄醚的较佳工艺条件是：110℃、反应3h、n(对甲苯酚)：n(氯化苄)为1：1．2、n(对甲苯酚)：n(氢氧化钠)为1：1．1；催化剂用量为9．26％(相对于对甲苯酚)，对甲苯苄醚的收率可达到93．43％以上，产品纯度为98．5％(质量分数)。     

Synthesis of polysiloxane–polyester copolymer by lipase‐catalyzed polycondensation

Polysiloxane–polyester copolymers have been synthesized for the first time by direct polycondensation of a series of diacids (butanedioic, hexanedioic, and octanedioic acid) and α,ω‐bis(3‐hydroxypropyl) polydimethylsiloxanes catalyzed with Novozyme‐435 in high yields (>90%) without the cleavage of Si? O bonds. The effects of monomer chain length, reaction temperature, and water removal method on the number–average molecular weight (M_n) of the resulted copolymers were investigated. Thermogravimetric and differential scanning calorimetry analyses indicated that the produced copolymer was more thermally stable than poly(1,8‐octyladipate) and the T_g was lowered to ?111°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

相转移催化剂上环戊烯选择氧化制备戊二酸

以双氧水为氧化剂,采用反应控制相转移催化剂催化环戊烯选择氧化制备戊二酸,考察反应条件的影响和催化剂回收。结果表明,催化剂最佳反应条件为催化剂用量为环戊烯质量的10%,双氧水和环戊烯物质的量比为4. 15∶1,反应温度90℃,反应时间5 h,最佳反应条件下戊二酸收率95. 67%,催化剂回收率66. 78%。通过高温分解反应液中残余双氧水可提高催化剂回收率。最佳分解温度为105℃,分解时间为6 h,分解反应后催化剂回收率79. 42%。实验室工艺条件下进行20 L放大试验,结果与小试无明显差别。     

低温溶液直接缩聚法制备浆粕状芳纶纤维

采用低温溶液缩聚法制备浆粕状芳纶纤维 ,且通过均匀设计来安排合成试验 ,采用数据组合法和单纯型寻优法建立了各影响因素与芳纶浆粕纤维特性粘数之间的回归模型 ,优化了合成工艺 ,为进一步研究制备浆粕状芳纶浆粕工艺奠定了基础     

Selective hydrogenation of nitrile‐butadiene rubber catalyzed by thermoregulated phase transfer phosphine rhodium complex

Hydrogenation of polymer having C?C double bond can be carried out with the metal–organic complex as catalyst, which has the property of themoregulated phase transfer. In this study, a new complex RhCl[PPh[(OCH₂CH₂)_5≤n≤6CH₃]₂]₃ (Rh/AEOPP) was synthesized with a good yield, which was further used as catalyst to selectively hydrogenated nitrile‐butadiene rubber (HNBR). This is the first time that Rh/AEOPP complex was synthesized and applied in nitrile‐butadiene rubber (NBR) hydrogenation. The result shows that hydrogenation degree of product (HNBR) can be extended to 90%, when the condition is [Cat] = 3% (based the weight of NBR), L₂: Cat (Weight Ratio) = 2, [NBR] = 5% (based on the weight of xylene solution), P (H₂) = 1.5 MPa, T = 155°C, and t = 8 h. Also, by adjusting temperature, the catalyst could be easily separated from products with 89% catalyst complex recovery. In addition, ¹H‐NMR and infrared (IR) spectra showed that C?C double bonds in NBR was successfully hydrogenated without causing reduction of the CN group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phase transfer catalysis in the polycondensation processes

Summary Polyesters from 3,3-bis(chloromethyl)oxacyclobutane and dipotassium isophthalate were obtained by phase transfer catalysis using different catalysts and solvents. The products were characterised by IR,¹H-NMR and DSC.     

Phase transfer catalysis in the polycondensation processes

Summary Rotation possibilities and rotational barriers in polyesters from 3,3-bis(chloromethyl)oxetane and dipotassium isophthalate were evidenced. Based on the obtained data it was presumed that every repeating unit behavies as a mesogenic, confering liquid-crystalline properties to the polyester.     

环己醇催化脱水制备环己烯

在催化剂ZrO2 SO42-存在下,研究了环己醇脱水制备环己烯的反应,考察了催化剂的用量、反应温度和反应时间对脱水反应的影响。最佳工艺条件为:催化剂用量为环己醇质量的10%,温度为170～180℃,反应时间1h,收率达87.4%。     

环己醇催化脱水制备环己烯的研究

研究了在催化剂SO4^2-/TiO2-SiO2存在下,环己醇脱水制备环己烯的反应。考察了催化剂用量、反应温度和反应时间对脱水反应的影响,得出最佳的工艺控制条件。     

Polymerization by phase transfer catalysis

Summary The hydrolysis of bisphenol A polythiocarbonate is studied under phase transfer conditions, and occurs principally in the organic phase, influenced by the catalysts according to their structure.For part 6, see the preceding paper     

Polymerization by phase transfer catalysis

Summary Polyethers from 1,4-bis(chloromethylene)-2,5-dimethoxybenzene and 4,4-biphenol were obtained by phase transfer catalysis, using different catalysts and solvents. The molecular weights and yields were determined, showing a solvent effect and a influence of the catalysts used.