Central, Ethyl Cyanoacetate Alkylation Reaction

Cycloalkylation compands of ethyl cyanoacetate,as one kind of the most important chemical materials,is a main intermediate for agricultural chemicals and many other fine chemicals.Cycloalkylation compands of ethyl cyanoacetate such as ethyl 4-Cyanotetrahydropyran-4-Carboxylate,ethyll-Cyanocyclobutane-1-Carboxylate,ethyl1-Cyanocyclopentane-1-Carboxylate were prepared from 2,2-dichloroethyl ether,1,3-dichloropropane,1,3-dibromropropane, 1,4-dichlorobutane and ethyl cyanoacetate.These compands were synthesized via Solid-Liquid Phase-Transfer Catalysis reaction and traditional method that used sodium ethylate as catalyst and ethanol as solvent.Comparing two methods,we gained the optimal process parameters for synthesizing these cycloalkylation compands of ethyl cyanoacetate. The product was determined by the ways of qualitative and amount analysis such as NMR,GC,MS-GAS.When we get these compands through traditional method that used sodium ethylate as catalyst and ethanol as solvent,made a research on the following factors such as material ratio,process of adding sodium ethylate.When we get these compands via Solid-Liquid Phase-Transfer Catalysis.This dissertation made a research on the following factors such as the time,the reaction temperature,the organic solvent,the water,the size and amount of potassium carbonate,the kind and amount of the catalyst,the halogen and the alkyl.Through the research of influencing factors,the optimized technology was as follows: the temperature is 110℃,the size of potassium carbonate is 160 mesh,n(K₂CO₃):n(PTC):n(C NCH₂COOC₂H₅)=1.5∶0.05∶1,agitation speed is 400 rpm and we used DMF as solven.When synthesizing 4-Cyanotetrahy-dropyran-4-Carboxylate and 1-Cyanocyclopentane-1-Carboxylate, we used DTMAB as catalyst.The yield of 4-Cyanotetrahydropyran-4-Carboxylate and ethyl 1-C-yanocyclopentane-1-Carboxylate is 93.6%,81.3%,the content is 97.1%,97.5%, but used 18-Crown-6 as catalyst and 1,3-dibromropropane as material for synthesizingethyl 1-Cyanocyclobutane-1-Caboxylate,the yield is 86.4%,the content is 97.9%,the reaction time is 2.5 h.The mechanism and kinetic of the reaction were also studied,the reaction can be described by the pseudo-second-order kinetics.At 80℃,95℃,112℃,when using 2,2-dichloroethyl ether,1,3-dibromropropane,1,4-dichlorobutane and ethyl cyanoacetate as bases,choosing toluene as solvent and DTMAB as catalyst,the apparent rate constant for systhesizing these products was obtained.