Synthesis of ethyl-6-aminohexanoate from caprolactam and ethanol in near-critical water

Abstract

The reaction between caprolactam and ethanol was performed in near-critical water. The primary product (ethyl-6-aminohexanoate) was identified by GC-MS. The influences of the reaction temperature, residence time, initial ratio (reactant/water), pH, and additives on the yields of ethyl-6-aminohexanoate are discussed. The results showed that the yield of ethyl-6-aminohexanoate could be as high as 98 % with SnCl2 as an additive in near-critical water. At the same time, the reaction between caprolactam and ethanol was estimated by a lumped kinetic equation as a second-order reaction in near-critical water, and the activation energy was evaluated according to the Arrhenius equation under acidic and basic conditions. Based on the results, the reaction mechanism between caprolactam and ethanol in near-critical water is proposed.

Industrially applied and relevant transformations of 1,3-butadiene using homogeneous catalysts

“…In addition, the chemical procedures from methyl-3-pentenoate to adipic acid/esters have also been established in >90% yield and about 80% selectivity, but the most prominent disadvantage is that the related processes are very complicated and involve multi-step processing. [171][172][173][174] Earlier in 1987, Drent and co-workers showed elegantly that the use of the ligand 2-pyridyl-diphenylphosphine 40 allows for exceptional activity in the carbonylation of propylene. It was speculated that the active catalytic species was stabilized by the hemilabile P-N coordination of the ligand.…”