A new process for the manufacture of p-xylylene dimethyl ether

Abstract

The invention provides a novel process of a 1,4-bis(methoxymethyl)-benzene preparation method. The novel process comprises the following steps of: (1) reaction distillation: heating low-boiling leftovers containing p-xylylene dichloride to reach the temperature above 110 DEG C, pumping into a reaction kettle under vacuum; adding sodium methoxide solution to react and distil at temperature below 80 to 100 DEG C, stopping reaction to obtain a crude product while the content of the p-xylylene dichloride residual in a reactant accounts for 0.05 to 0.5% (GC), and distilling to obtain methanol; (2) salt dissolving: adding water to the crude product to dissolve salt; (3) heating reflux: heating for 3 to 5 hours to reach 95 to 105 DEG C; (4) standing and layering to obtain an oil layer and a water layer; (5) rectifying: performing reduced pressure distillation to the oil layer to obtain finished 1,4-bis(methoxymethyl)-benzene and a byproduct finished p-tolualdehyde. The novel process is simple, convenient and stable in operation process, active substance can be fully utilized and the generation of three wastes (waste gas, waste water, and industrial residue) is reduced in the process of producing the p-xylylene dichloride.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a new process for producing p-xylylene dimethyl ether. Background technique [0002] The report of the synthetic method of p-xylylene dimethyl ether is rare, and the present applicant's existing a kind of production technique scheme process is described as follows: [0003] Put the finished p-dichlorobenzyl crystal into the reaction kettle, put in a certain amount of methanol, and then raise the temperature. After the temperature in the kettle rises to the range of the process control index, drop the prepared sodium methoxide solution at a certain flow rate. The dropping process After completion, start to raise the temperature and reflux for 3 hours, then distill methanol. After all the methanol is distilled off, add water to dissolve the crude product of the reactant, cool, let stand to separate layers, and remove the lower layer of brine. The oil layer is rectified under vacuu...

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Problems solved by technology

[0004] The existing shortcomings in the production process of the existing production process: 1. Although p-dichlorobenzene, the raw material for the etherification reaction, is a product produced by the company itself, p-dichlorobenzyl is obtained by condensing, crystallizing and centrifugally drying the offal of p-methyl chloride benzyl , During the production process, a considerable part of the organized exhaust gas and dust will directly contact the air and pollute the air; 2. During the feeding process of solid materials, it is easy to generate smoke, which is not only not environmentally friendly but also easy to cause harm to the operator's body

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