Kinetics and a Mechanistic Investigation of one-pot multicomponent synthesis of piperidines: a mechanistic investigation

Some different types of solvent effect can be categorized on reaction rates, on the position of chemical equilibrium, on competitive reaction mechanisms, on chemoselectivity and on stereoselectivity. According to their solvents sensitivity, most organic reactions can be classified into dipolar transition state, isopolar transition state, nonpolar transition state and etc. For further study in this case, formation of substituted piperidine ۸ from the reaction between ۴-methyl-benzaldehyde ۱, aniline ۲ and ethyl acetoacetate ۳ in the presence of oxalic acid dihydrate was kinetically considered at ambient temperature in both methanol and ethanol media. Oxalic acid dihydrate not only is a highly effective and capable catalyst but also is an environmentally friendly compound. Hence kinetics and a mechanistic investigation of mentioned reaction was performed by UV/vis spectrophotometry technique. Based on the experiment data, the overall order of the reaction is two. The reaction was repeated at different temperatures and the dependence of overall rate constant Ln kove or (Ln kove/T) on reciprocal temperature were in a good agreement with Arrhenius and Eyring equations, respectively.

Keywords:

Kinetic and Mechanistic Investigation , Catalyst , Oxalic acid dihydrate , Multicomponent Reaction , UV spectrophotometry , Piperidine