The Aei New Zeolite Catalyst Precursor Hydroxide Of N-, N-diethyl-2 ,6 - Dimethylpiperidine Onium Synthesis

In China, there is a strong demand for propylene, which is an important basic organic raw material. The technology of MTP has a extensive application prospect in industrial. With high catalytic activity and propylene selectivity, silicon aluminium molecular sifter catalyst which has the structure of AEI becomes the new catalyst of MTP. In the process to synthesize catalyst, template preparation is the first problem to be faced. The template is not a commonly used chemicals, which can't be procured in the domestic market. Therefore, we should firstly synthesize the template DEMP+OH-.In order to synthesize the template DEMP+OH-, we designed two process routes:one is hydrogenation-distillation-alkylation-split phase separation-alkylation-split phase separation; the other is hydrogenation-alkylation-split phase separation-alkylation-split phase separation. Through the investigation of the two routes, we believe that the second route is the optimal one.With 2,6-dimethylpyridine as the starting reactant, we use the method of catalytic hydrogenation to compound 2,6-dimethylpiperidine. Pd/C is the optimal catalyst for the reaction. The optimal reaction conditions are 10% catalyst amount 1.8%(wt), reaction temperature 120℃, ethanol solvent ratio 1:3(V), reaction time 6h. In the conditions, the 2,6-dimethylpyridine conversion is 79.1% and 2,6-dimethylpiperidine selectivity is 100%.In the research on N-alkylation, the hydrogenation reaction product mixture is used as starting material, and diethyl sulfate as alkylating agent. The optimal reaction conditions to synthesize N-ethyl-2,6-dimethyl piperidine are molar ratio(2,6-dimethyl piperidine:diethyl sulfate)= 1:3(m), reaction temperature 60℃, reaction time 7h, flask with reflux condensation. In the conditions, the 2,6-dimethylpiperidine conversion is 71.9% and N-ethyl-2,6-dimethyl-piperidine selectivity is 99.9%.Split phase separation, as a substitute for distillation separation method, can avoid the loss of raw materials in the distillation column; at the same time, it can protect the alkylation products because of not heating.