抄録
In the presence of catalytic piperidine, various alkyl cyanoacetates were treated with formaldehyde using the corresponding alcohols as solvents in homogeneousand heterogeneous systems. In homogeneous systems, the reaction velocities at 50°C decreased in the following order : methyl>ethyl>n-butyl>isobutyl>isopropyl. The reaction was first order in the concentration of catalyst and second order in the concentrations of the cyanoacetate and formaldehyde. The activation energies were calculated to be : methyl 15.7, ethyl 14.6, isopropyl 13.9, n-butyl 14.6, and isobutyl 13.5 Kcal/mol, indicating the readiness of this type of reactions. In heterogeneous systems, the reaction velocities at 50°C decreased in the following order : methyl>n-butyl>ethyl>isobutyl>isopropyl>cyclohexyl>2-ethylhexyl. The reaction was first order in the concentrations of catalyst and the cyanoacetate. The activation energies were calculated to be : methyl 15.3, ethyl 14.2, isopropyl 14.0, n-butyl 15.1, isobutyl 16.1, cyclohexyl 15.8, and 2-ethylhexyl 14.3 Kcal/mol. It seems likely that this type of reaction proceeds through additive condensation.
