A chloromethylated styrene-divinylbenzene copolymer support system functionalized with 4-benzaldehyde and 2-benzaldehyde was prepared. The degree of functionalization with aldehyde groups is well suited for the subseq...A chloromethylated styrene-divinylbenzene copolymer support system functionalized with 4-benzaldehyde and 2-benzaldehyde was prepared. The degree of functionalization with aldehyde groups is well suited for the subsequent use of the products as Wittig reagents. The polymer bound aldehyde was reacted with Wittig reagents to give olefin groups grafted on styrene-divinylbenzene copolymers. The reactions were carded out in phase transfer catalysis conditions. A simple procedure for the calculation of the degree of functionalization and the statistical modeling of the structural repetitive unit of the copolymer are reported.展开更多
Ⅰ. INTRODUCTIONWittig reaction has been widely used in the syntheses of insect pheromones. However, the conventional route is not suitable for large-scale syntheses because it is hard to operate. The successful appli...Ⅰ. INTRODUCTIONWittig reaction has been widely used in the syntheses of insect pheromones. However, the conventional route is not suitable for large-scale syntheses because it is hard to operate. The successful application of phasc transfer catalysis makes the operation of Wittig reaction markedly convenient. At prcsent more investigations on PTC Wittig reaction have bccn reported. But almost all arc on the PTC展开更多
以季铵盐为催化剂,采用液-液相转移催化法,进行弱酸性的苄基二乙基膦酸酯与芳香醛反应生成二苯乙烯类化合物的动力学实验。在对反应机理分析的基础上建立动力学模型。考察了搅拌转速、催化剂种类与用量、反应温度、芳香醛种类和盐类对...以季铵盐为催化剂,采用液-液相转移催化法,进行弱酸性的苄基二乙基膦酸酯与芳香醛反应生成二苯乙烯类化合物的动力学实验。在对反应机理分析的基础上建立动力学模型。考察了搅拌转速、催化剂种类与用量、反应温度、芳香醛种类和盐类对准一级反应速率常数的影响。实验结果表明,在液-液相转移催化体系中,苄基二乙基膦酸酯与芳香醛的反应历程为萃取机理,合成二苯乙烯和4-甲氧基二苯乙烯的活化能分别为24.27 k J/mol和26.65 k J/mol;亲油性强的季铵盐催化活性高;含吸电子基的芳香醛反应活性高,但易发生副反应,产物收率低;盐的阴离子影响离子交换和离子对的传质,加入适量的Na Cl可以促进第三相的形成,提高反应速率。展开更多
文摘A chloromethylated styrene-divinylbenzene copolymer support system functionalized with 4-benzaldehyde and 2-benzaldehyde was prepared. The degree of functionalization with aldehyde groups is well suited for the subsequent use of the products as Wittig reagents. The polymer bound aldehyde was reacted with Wittig reagents to give olefin groups grafted on styrene-divinylbenzene copolymers. The reactions were carded out in phase transfer catalysis conditions. A simple procedure for the calculation of the degree of functionalization and the statistical modeling of the structural repetitive unit of the copolymer are reported.
文摘Ⅰ. INTRODUCTIONWittig reaction has been widely used in the syntheses of insect pheromones. However, the conventional route is not suitable for large-scale syntheses because it is hard to operate. The successful application of phasc transfer catalysis makes the operation of Wittig reaction markedly convenient. At prcsent more investigations on PTC Wittig reaction have bccn reported. But almost all arc on the PTC
文摘以季铵盐为催化剂,采用液-液相转移催化法,进行弱酸性的苄基二乙基膦酸酯与芳香醛反应生成二苯乙烯类化合物的动力学实验。在对反应机理分析的基础上建立动力学模型。考察了搅拌转速、催化剂种类与用量、反应温度、芳香醛种类和盐类对准一级反应速率常数的影响。实验结果表明,在液-液相转移催化体系中,苄基二乙基膦酸酯与芳香醛的反应历程为萃取机理,合成二苯乙烯和4-甲氧基二苯乙烯的活化能分别为24.27 k J/mol和26.65 k J/mol;亲油性强的季铵盐催化活性高;含吸电子基的芳香醛反应活性高,但易发生副反应,产物收率低;盐的阴离子影响离子交换和离子对的传质,加入适量的Na Cl可以促进第三相的形成,提高反应速率。