Research about the Method of Synthesizing N,N-dimethyl- 1,3-propanediamine Continuously

Abstract

N,N-dimethyl-1,3-propanediamine (DMAPA) is an important fine organic chemical intermediate, is widely used in the manufacturing of surfactants, cosmetics, detergents, textiles, and lubricating oil additives. Although market need is growing increasingly, but research report about the manufacturing process of DMAPA is not investigated explicitly. The current preparation of DMAPA is a two-step batch reation. In the first step Dimethyl amine(DMA) and Acrylonitrile(ACN) as the starting materials lead to N, N-dimethyl-amino propionitrile (DMAPN). Then, DMAPN is hydrogenated to obtain DMAPA by Raney-Ni. Herein, we focus on realizing the two step in a continuous process using fixed bed. In the first step, the reaction conditions using fillers can achieve the effect of catalyst H-ZSM-5. Under an optimized the conditions 30 °C 1.0M Pa, LHSV 1.1~4h-1 and molar ration of 1.00:1.00, the reaction conversion and selectivitywere higher than 99.5 %. Later, we exploit hydrogenation of DMAPN in a continuous process catalyzed by ZL-311-R. Under an optimized the conditions 70 °C, 6 MPa, LHSV 0.3 h-1, alkali liquor NaOH, the reaction conversion and selectivity were higher than 99.5 %. Realize synthesizing N,N-dimethyl-1,3-propanediamine continuously in the fixed bed and reaction conversion and selectivity were all higher than99.5 % in the two step.