Method for preparing halopropyl alcohol and propylene oxide

Abstract

The invention provides a halopropyl alcohol preparation method, which comprises: (1) a catalyst acid treatment: soaking a catalyst in an acid, washing the catalyst, and drying the catalyst; (2) halo alcoholization: adding hydrogen halide, H2O2, propylene and the catalyst treated in the step (1) to a reaction device, and carrying out a halo alcoholization reaction to obtain halopropyl alcohol; optionally, (3) saponification: carrying out a saponification reaction on the halopropyl alcohol obtained in the step (2) and an alkali metal hydroxide, and separating to obtain propylene oxide and a halogenated alkali metal salt; and optionally, (4) electrodialysis: carrying out bipolar membrane electrodialysis on the halogenated alkali metal salt obtained in the step (3) to obtain the hydroxide of the alkali metal and the hydrogen halide. With the method of the present invention, the halopropyl alcohol can be produced in the extremely high selectivity and extremely high yield manner, and the emissions of wastewater and waste residue are substantially reduced.

Description

technical field [0001] The present invention relates to a method for preparing halopropanol, and a method for preparing propylene oxide from halopropanol; more specifically, it provides a method for preparing halopropanol by using propylene as a raw material and adopting a new halohydrin method, and using a new halohydrin Method for preparing propylene oxide. Background technique [0002] Propylene oxide (hereinafter referred to as PO) is an important organic chemical raw material. As the third largest derivative of propylene series, its biggest application is the preparation of polyether polyols, as well as the production of propylene glycol and nonionic surfactants. In recent years, PO is also widely used in the synthesis of green products such as dimethyl carbonate and carbon dioxide polymer. [0003] The production process of propylene oxide mainly includes chloroalcoholization method, co-oxidation method (also called indirect oxidation method) and direct oxidation met...

AI Technical Summary

Problems solved by technology

[0005] The preparation of propylene oxide by the chlorohydrin method of the prior art mainly has the following problems: 1. raw material chlorine and propylene undergo an addition side reaction to generate dichloropropane

Dichloropropane is difficult to utilize and wastes a lot of raw materials

In addition, chlorine gas reacts with propylene to release a large amount of heat, which is concentrated in the reaction vessel, resulting in great production hazards.

②A small amount of oxygen is inevitably entrained in the raw material chlorine gas during the production process. As the reaction proceeds, chlorine gas continuously participates in the reaction, so chlorine gas needs to be continuously replenished, while oxygen cannot participate in the reaction and accumulates in the reaction device continuously. , the oxygen concentration keeps rising, and the reaction releases heat. Oxygen, chlorine, and propylene exist at the same time, and it is easy to cause an explosion at high temperature.

④The reaction produces a large amount of calcium chloride, which leads to high COD of wastewater and pollutes the environment

⑤ The disadvantage of the chlorohydrin method is that it consumes a lot of water resources and produces a large amount of waste water and waste residue. The production of 1t of propylene oxide by the chlorohydrin method produces 40-50t of chloride-containing waste water and 2.1t of calcium chloride waste residue. The waste water has high temperature and pH The "five highs" characteristics of high value, high chlorine content, high COD content and high suspended solids content are difficult to handle and seriously pollute the environment

⑥ The hypochlorous acid produced in the production process also seriously corrodes the equipment

Images