Affiliation:
1. School of Chemistry and Environment Engineering China University of Mining and Technology (Beijing) Beijing 100083 China
2. School of Chemistry and Chemical Engineering Beijing Key Laboratory for Chemical Power Source and Green Catalysis Beijing Institute of Technology Beijing 100081 China
3. Beijing Key Laboratory of Ionic Liquids Clean Processes Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China
Abstract
AbstractThe vapor‐phase nitrilation of dimethyl adipate (DMA) with ammonia (NH3) is an environmentally benign route leading to adiponitrile (ADN) with great application value. In this study, the performance of HZSM‐5 zeolites, widely used in industry as the solid acid catalysts, was investigated. It exhibits a strong correlation between the SiO2/Al2O3 ratio (SAR) in HZSM‐5 zeolites and the reactivity (both activity and selectivity). The influence of Al density closely related to the value of SAR on the reactivity of HZSM‐5 was thus elucidated by mechanistic experiments. As a result, the introduction of Al element to the framework is beneficial to the activation of ester functionality, thus improving the activity, especially at a high liquid hourly space velocity (LHSV). However, a high Al density will lead to poor selectivity and deactivation due to too strong adsorption of esters and intermediates (e. g., amides). Herein, the balanced adsorption/desorption capability was reached on HZSM‐5 with SAR as 631 (i. e., HZSM‐5‐631), which provides the best selectivity to nitriles (SADN+MCP, 92.5 %) at a high single‐pass conversion of DMA (CDMA, 98.0 %).
Funder
National Natural Science Foundation of China
Shanxi Provincial Key Research and Development Project
Fundamental Research Funds for the Central Universities
Natural Science Foundation of Beijing Municipality