ANALYSIS OF FACTORS AFFECTING THE SYNTHESIS OF ALLYL PHENYL ETHER BY TRI-LIQUID-PHASE CATALYSIS

In order to improve the selectivity of allyl phenyl ether (ROPh), the main product, in the etherification of allyl bromide (RBr) and sodium phenolate (NaOPh) with tetra-n-butylammonium bromide (QBr) as a phase-transfer catalyst, the technique of tri-liquid-phase phase-transfer catalysis, instead of the liquid-liquid one, was employed. The reaction was performed in a batch reactor, and the factors affecting the conversion and selectivity were investigated. The possibility of reusing the phase-transfer catalyst was also evaluated. Experimental results indicate that the addition of a small amount of Na₂CO₃ will benefit the formation of a third liquid phase and enhances both the conversion of RBr and the overall yield of ROPh. Both the conversion and the overall yield are maximal when the mole fraction of QBr in the mixture of NaOPh and QBr is about 0.3. A high reaction temperature enhances the conversion and the overall yield. Under optimal conditions, complete conversion and near 100% yield can be obtained within 10 minutes. Although the reaction rate by the tri-liquid-phase catalysis is slightly lower than that observed with the same amount of catalyst by conventional liquid-liquid phase-transfer catalysis, the selectivity of ROPh is higher and the catalyst can be easily reused by the reuse of the third liquid phase without any loss of its catalytic activity in the former case. Because the reuse of catalyst was found to be feasible, the production of ROPh with a continuous-flow reactor becomes possible.     

ANALYSIS OF FACTORS AFFECTING THE SYNTHESIS OF ALLYL PHENYL ETHER BY TRI-LIQUID-PHASE CATALYSIS

In order to improve the selectivity of allyl phenyl ether (ROPh), the main product, in the etherification of allyl bromide (RBr) and sodium phenolate (NaOPh) with tetra-n-butylammonium bromide (QBr) as a phase-transfer catalyst, the technique of tri-liquid-phase phase-transfer catalysis, instead of the liquid-liquid one, was employed. The reaction was performed in a batch reactor, and the factors affecting the conversion and selectivity were investigated. The possibility of reusing the phase-transfer catalyst was also evaluated. Experimental results indicate that the addition of a small amount of Na₂CO₃ will benefit the formation of a third liquid phase and enhances both the conversion of RBr and the overall yield of ROPh. Both the conversion and the overall yield are maximal when the mole fraction of QBr in the mixture of NaOPh and QBr is about 0.3. A high reaction temperature enhances the conversion and the overall yield. Under optimal conditions, complete conversion and near 100% yield can be obtained within 10 minutes. Although the reaction rate by the tri-liquid-phase catalysis is slightly lower than that observed with the same amount of catalyst by conventional liquid-liquid phase-transfer catalysis, the selectivity of ROPh is higher and the catalyst can be easily reused by the reuse of the third liquid phase without any loss of its catalytic activity in the former case. Because the reuse of catalyst was found to be feasible, the production of ROPh with a continuous-flow reactor becomes possible.     

垂直筛板塔内催化剂筐式装填结构的流体力学研究

基于垂直筛板帽罩的垂直特性,开发了一类用于催化精馏的新型催化剂筐式装填结构.该结构的主要特点为:均匀装填催化剂的催化剂筐置于帽罩外侧;气相与被提升的液相在帽罩内形成的气液混合物从罩孔喷出后进入筐内的催化剂床层:床层内的气-液-固的有效接触可显著促进非均相催化反应的进行.用空气-水体系在内径ψ48 mm冷模塔上考察了催化剂筐式装填结构的结构参数(帽罩形式、帽罩孔径和开孔率)对装填结构流体力学性能的影响;并根据操作范围和干板、湿板压降等因素对其进行了优化.研究结果表明基于柱形帽罩的催化剂筐式装填结构的气-液-固三相的接触状态优于基于矩形帽罩的:帽罩孔径ψ2 mm和开孔率0.056时的气-液-固接触效果和塔操作状态最佳.     

KINETIC STUDY OF SYNTHESIZING DIALKOXYMETHANE USING 4-(TRIALKYLAMMONIUM) PROPANSULTANS AS NEW PHASE-TRANSFER CATALYSTS

In this work, sulfobetaine (4-(trialkylammonium) propansultan (TAAPS)) was first developed as a new phase-transfer catalyst for synthesizing dialkoxymethane. The addition reaction of 1,3-propane sultone (PS) and trialkylamines (TAA) was successfully carried out to synthesize sulfobetaines in a homogeneous organic solution. In this work, for the first time, five different TAAPSs, which possess high reactivity, stability, selectivity, and performance, were employed as phase-transfer catalysis to synthesize dialkoxymethane. The reaction of alcohol and dibromomethane in a highly alkaline solution of KOH/organic solvent two-phase medium to produce dialkoxymethane was carried out under phase-transfer catalysis using 4-(trialkylammonium) propansultan as the catalyst. From the experimental observation, a rational reaction mechanism using this new phase-transfer catalyst was proposed. Kinetics of the reaction are studied in detail.     

KINETIC STUDY OF SYNTHESIZING DIALKOXYMETHANE USING 4-(TRIALKYLAMMONIUM) PROPANSULTANS AS NEW PHASE-TRANSFER CATALYSTS

In this work, sulfobetaine (4-(trialkylammonium) propansultan (TAAPS)) was first developed as a new phase-transfer catalyst for synthesizing dialkoxymethane. The addition reaction of 1,3-propane sultone (PS) and trialkylamines (TAA) was successfully carried out to synthesize sulfobetaines in a homogeneous organic solution. In this work, for the first time, five different TAAPSs, which possess high reactivity, stability, selectivity, and performance, were employed as phase-transfer catalysis to synthesize dialkoxymethane. The reaction of alcohol and dibromomethane in a highly alkaline solution of KOH/organic solvent two-phase medium to produce dialkoxymethane was carried out under phase-transfer catalysis using 4-(trialkylammonium) propansultan as the catalyst. From the experimental observation, a rational reaction mechanism using this new phase-transfer catalyst was proposed. Kinetics of the reaction are studied in detail.     

PHASE-TRANSFER CATALYZED BENZOYLATION OF 4-CHLORO-3-METHYLPHENOL SODIUM SALT IN LIQUID-LIQUID SYSTEM

The reaction of sodium 4-chloro-3-methylphenoxide (ArONa) and benzoyl chloride (ROCl) to synthesize 4-chloro-3-methylphenyl benzoate (ArOOR) was investigated by liquid-liquid phase-transfer catalysis in the present study. The catalytic intermediate was synthesized and its behaviors during the reaction were explored. The product yield was above 97.2% within 0.5 h of reaction at 10°C and 100 rpm using tetrabutylammonium bromide as the catalyst. The benzoylation reaction was governed by the interfacial reaction and the intrinsic reaction in the bulk phase. During the reaction, a fraction (0.55-0.65) of the catalyst was observed in the form of catalytic intermediate, tetrabutylammonium 4-chloro-3-methylphenoxide (ArOQ), and its concentration would be near constant after 6 min of induction period. A reaction mechanism and pseudo-first-order kinetics were proposed to describe this phase-transfer catalyzed benzoylation successfully. Extra additions of NaCl and NaBr in the aqueous phase would increase the concentration of ArOQ in the organic phase to enhance the overall reaction, while a poison effect was observed for extra addition of NaI. A more hydrophilic catalyst, tetrabutylammonium hydrogen sulfate, was also favorable to conduct this type of interfacial intrinsic reaction with the apparent activation energy 7.13 kcal/mol.     

PHASE-TRANSFER CATALYZED BENZOYLATION OF 4-CHLORO-3-METHYLPHENOL SODIUM SALT IN LIQUID-LIQUID SYSTEM

The reaction of sodium 4-chloro-3-methylphenoxide (ArONa) and benzoyl chloride (ROCl) to synthesize 4-chloro-3-methylphenyl benzoate (ArOOR) was investigated by liquid-liquid phase-transfer catalysis in the present study. The catalytic intermediate was synthesized and its behaviors during the reaction were explored. The product yield was above 97.2% within 0.5 h of reaction at 10°C and 100 rpm using tetrabutylammonium bromide as the catalyst. The benzoylation reaction was governed by the interfacial reaction and the intrinsic reaction in the bulk phase. During the reaction, a fraction (0.55–0.65) of the catalyst was observed in the form of catalytic intermediate, tetrabutylammonium 4-chloro-3-methylphenoxide (ArOQ), and its concentration would be near constant after 6 min of induction period. A reaction mechanism and pseudo-first-order kinetics were proposed to describe this phase-transfer catalyzed benzoylation successfully. Extra additions of NaCl and NaBr in the aqueous phase would increase the concentration of ArOQ in the organic phase to enhance the overall reaction, while a poison effect was observed for extra addition of NaI. A more hydrophilic catalyst, tetrabutylammonium hydrogen sulfate, was also favorable to conduct this type of interfacial intrinsic reaction with the apparent activation energy 7.13 kcal/mol.     

Kinetics for benzoylation of sodium 4-acetylphenoxide via third-liquid phase in the phase-transfer catalysis

In this research, the kinetics for synthesizing 4-acetylphenyl benzoate (R^*COOR) from benzoylation of sodium 4-acetylphenoxide via third-liquid phase-transfer catalysis was investigated. The reaction rate was observed to be strongly dependent on agitation speeds in the third-phase catalytic reaction. By forming the third-liquid phase, the observed reaction can be greatly enhanced to give a product yield of 100% in a duration of 3 min at 20 °C and 200 rpm. If a third-liquid phase was not formed in the liquid–liquid system, the reaction rate is very slow and the product yield is only 2% in 3 min at 20 °C. The reaction conducted in third-liquid phase-transfer catalytic system is faster than that in LLPTC system by 25–28 times. The amount of catalytic intermediate (QOR) in the third-liquid phase was about 50% of the catalyst initially added and kept about 30% of it remained after 1 min, and only small amounts of a catalytic intermediate residing in the organic phase were observed during the reaction using methyl t-butyl ether as the solvent. The concentration of catalytic intermediate slightly decreased with increasing reaction time, while the molar ratio of QOR to benzyl tri-n-butylammonium cation in the third-liquid phase remained almost constant after 1 min and increased with increasing agitation speeds. The experimental results were well described by the pseudo-first-order kinetics. The present work shows an effective method to synthesize 4-acetylphenyl benzoate.     

Multi-scale catalyst design

Catalyst design has long been sought in catalysis and reaction engineering research. In this work, multi-scale analysis and strategy is explored to take a holistic view toward catalyst design perspective and elucidate impacts of designs at different scales to a catalytic reaction process performance. A few promising design concepts are introduced to break the compromise that often needs to be made in the conventional design approach. In the catalyst bed scale, micro- or mini-structured catalyst designs can be used to potentially eliminate all mass transfer resistance and realize intrinsic catalytic performance. At the particle level, incorporation of membrane separation functions into the catalyst unit enables regulation of mass transfer rate of individual reactant or product molecules that high reaction selectivity is achieved. At the level of intrinsic catalyst structures, three-dimensional (3-D) catalyst design models are outlined here to outweigh limitations or constraints imposed by the conventional way of thinking 2-D catalyst surface. Examples of exceptional catalytic activity or concerted effects are shown by incorporating different materials into nano-composite catalysts and optimizing size and/or shape of a catalyst material at the nano-scale.     

相转移催化法合成邻硝基茴香醚

论述了以相转移催化剂催化合成邻硝基茴香醚的新方法。在相转移催化剂存在下，于常压、回流温度下滴加浓碱合成了邻硝基茴香醚，产品收率达85%。探讨了催化剂类型、用量、碱的浓度、反应时间等对应的影响，确定了最佳工艺条件。     

Thermoregulated phase-transfer rhodium nanoparticle catalyst for hydroaminomethylation of olefins

Rh nanoparticles used as catalysts for hydroaminomethylation reaction is reported for the first time. An efficient and recyclable Rh nanoparticle catalyst stabilized by thermoregulated ligand Ph₂P(CH₂CH₂O)_nCH₃ (n = 16) was studied for the hydroaminomethylation of olefins in the aqueous/1-butanol biphasic system through thermoregulated phase-transfer catalysis, which allows not only for a homogeneous catalytic reaction, but also for an easy biphasic separation. Under the optimized conditions, the conversion of 1-octene and the product amine selectivity were as high as 99% and 97%, respectively. After reaction, the Rh nanoparticle catalyst can be separated from products by simple phase separation and recycled directly for the next run.     

水/有机两相温控相转移催化新进展

综述了水/有机两相"温控相转移催化"的原理,在此基础上设计、合成了以非离子型水溶性膦配体和两性双吡啶配体,并与过渡金属络合制备出温控相转移催化剂。综述了其在水/有机两相CO还原,烯烃加氢和Heck反应中的应用效果。     

由碳酸二甲酯合成芳香醚的绿色工艺

综述了酚类化合物与碳酸二甲酯(DMC)甲基化反应合成芳香醚的绿色工艺。气相连续流动法和液相间歇法是2种有效的由DMC合成芳香醚的方法。在气液相转移催化和液固相转移催化的条件下,酚与DMC甲基化反应的产率和选择性均很高。酚与DMC甲基化反应的均相催化剂一般选择叔胺、叔膦、季铵盐及Schiff碱等有机碱,多相催化剂为碱金属碳酸盐、沸石、氧化铝及附载有金属盐的氧化铝和煅烧的Mg-Al水滑石。     

四丁基溴化铵催化过氧化氢氧化香紫苏醇合成香紫苏内酯的研究

在有机溶剂中,以质量分数30%过氧化氢作氧源,四丁基溴化铵为相转移催化剂,钨酸钠、硫酸氢钠为酸性催化剂,催化氧化香紫苏醇合成香紫苏内酯,考察了硫酸氢钠、钨酸钠、四丁基溴化铵用量和反应时间对反应的影响。当n（香紫苏醇）：n（双氧水）：n（四丁基溴化铵）：n（钨酸钠）：n（硫酸氢钠）=100：300：2：1：1,在回流温度下,反应6h,产率可达72%。     

相转移催化水解制备对氯苯甲醛

采用相转移催化剂,研究了对氯苄叉二氯水解制备对氯苯甲醛的反应,考察了催化剂种类和用量、水的用量、反应温度和水解母液对水解反应的影响,建立了对氯苄叉二氯相转移催化水解制备对氯苯甲醛的宏观动力学模型.实验结果表明,以苄基三乙基氯化铵为对氯苄叉二氯水解制备对氯苯甲醛的相转移催化剂,适宜的水解反应条件为催化剂用量为对氯变叉二氯质量的0.2%,水与对氯变叉二氯的质量比为2.4∶1,反应温度100 ℃.在此条件下,对氯苄叉二氯水解转化率达99%以上.对氯苄叉二氯相转移催化水解制备对氯苯甲醛的反应为拟一级反应,活化能为83.59 kJ/mol,频率因子为1.288×1010 min-1.     

Kinetics of formation of diphenoxymethane from phenol and dichloromethane using phase-transfer catalysis

The reactions of phenol with dichloromethane using quaternary ammonium salts as a liquid–liquid phase-transfer catalyst in an organic solvent/alkaline solution were investigated. The technique of phase-transfer catalysis had a dramatic accelerating effect on the reaction and increased the yield of diphenoxymethane by more than 95%. The effects of catalysts, temperature, and basic concentration on reaction rate were studied in order to find the optimum operating conditions for this reaction. Experimental results indicated that a potassium hydroxide was preferred over sodium hydroxide in order to enhance the reactivity of the reaction. The reaction rate constant and the distribution coefficient of the intermediate product were obtained. During the reaction, the concentration of the intermediate product was also measured in order to study its behavior in the liquid–liquid system.     

Phase-transfer catalysis of the reaction of α-bromo-p-xylene with iron carbonyls

The carbonylation of α-Bromo-p-xylene (BrCH₂C₆H₄CH₃, BX) with iron pentacarbonyl (Fe(CO)₅) by phase-transfer catalysis was studied in an organic solvent/alkaline solution. The reaction mechanism was corrected and clarified. The concentrations of base, reactant and catalyst, volume ratio, the kind of catalysts, organometals and solvents were evaluated to find the optimum condition in this reaction. The technique of phase-transfer catalysis has a dramatic accelerating effect on the reaction. In examining eight kinds of phase-transfer catalysts, tetra-n-butylammonium cation and tetra-n-butylphosphonium cation were found to be the best for increasing the yield of bis(p-methylbenzyl) ketone ((p-CH₃C₆H₄CH₂)₂CO, BMBK). The amount of phase-transfer catalyst, the concentration of NaOH, the molar ratio of BX to Fe(CO)₅ and the volume ratio of aqueous to organic phase affected the product selectivity.     

杂质离子对甲醇羰基化制醋酸铱基催化体系的影响

醋酸是一种重要的化工原料,甲醇羰基化是目前生产醋酸的主要方法,铱基催化剂是最有发展前景的甲醇羰基化反应制备醋酸的催化剂。本文介绍了铱基催化剂体系的催化机理,考察了腐蚀性金属和碱金属对单铱催化体系的催化效果的影响。