过氧酸与丙烯及衍生物环氧化反应的机理研究

Epoxidation reaction mechanism of peracid with propylene and Its derivatives

本文在M06-2X(SMD,H_2O)/6-31++G(d,p)水平下研究了水溶液中过氧甲酸与CH_2XCHCHY(Y=H,X=H,CH_3,Cl及X=H,Y=CH_3,Cl)以及丙烯与ZCOOOH(Z=CF3和CH_3)的环氧化反应。热力学数据表明该环氧化反应是可能的。反应为一步协同机理。反应底物分别为丙烯、丁烯、3-氯丙烯、2-丁烯、氯丙烯时,与过氧甲酸环氧化反应所需要的活化能为:129.7、130.6、139.4、121.2和137.9 kJ·mol^(-1)。过氧酸为过氧乙酸和过氧化三氟乙酸时,与丙烯反应的活化能为136.3和116.7 kJ·mol^(-1)。表明反应在动力学上是可行的。同时,烯烃上取代基X,Y为供电子基团时,反应能垒最小,反应最容易进行。过氧酸上连接吸电基时反应的活化能最低。

The epoxidation reaction mechanism of peroxyformic acid with CH2XCHCHY（Y = H,X = H , CH3 Cl and X = H,Y = C H 3, Cl）and propylene with ZC000H（Z = CF3 和 CH3 ）has been investigated at the M06-2X（SMD, H 2O） / 6- 31 ＋ ＋ G （ d, p）level.Ther- modynamic data indicates that the reaction is possible. The reaction mechanism is synergy mechanism. It is indicated that the activa-tion energy value for the reaction HC000H ＋ CH2XCHCHY → HCOOH ＋ CH2XCH0CHY（ Y = H, X = H, CH3 Cl and X = H,Y = CH3 ,Cl） werel29. 7,130. 6,139. 4,121. 2 and 137.9 kj · mol-1.The activation energy value were 136.3,116.7 kj · mol-1 when peracid are peracetic and trifluoroacetic. These values indicates that the reaction is feasible in kinetics. In addition,the reaction is more advantageous when X,Y is a electron-donating group,or Z is a electron-withdrawing group.