Method for preparing phenol

Abstract

The invention relates to a method for preparing phenol, which can be used for continuous production as well as improving the production efficiency and reaction yield. The method for preparing phenol comprises arylsulphonate and alkali have alkaline fusion reaction, and is characterized in that the alkaline fusion reaction is carried out in a screw reactor which is a known reactor. As a preferableproposal, the screw reactor is a double-screw extrusion reactor, and both the arylsulphonate and the alkali are solid. Compared with the traditional intermittent kettle type alkaline fusion method, the method of the invention shortens the reaction time by two thirds, obviously reduces the phenomena of material coking and decomposition, improves the reaction yield to be more than 10%, and increasesthe crude phenol content by over 90%. As arylsulphonate solid is applied in the reaction, the water vapor containing phenol generated in the alkaline fusion process can be greatly reduced, the processing is simple, environmental protection burden can be remarkably alleviated, and the method is in accordance with the existing national energy-saving and emission-reduction industrial policy.

Description

technical field [0001] The invention relates to a preparation method of phenol. Background technique [0002] Phenols are an important class of chemical substances whose chemical structure is characterized by substituted hydroxyl groups on the aromatic rings. The preparation of phenol usually adopts the alkali fusion method of aryl sulfonate, that is, the alkali fusion reaction of aryl sulfonate and alkali produces phenoxide, which is acidified and purified to obtain phenol. [0003] Among phenolic substances, p-cresol is an important organic chemical intermediate, which is widely used in medicine, spices and plastics industries. At present, p-cresol is produced by sulfonation and alkali fusion process routes. That is, toluene sulfonation produces p-toluenesulfonic acid, and p-toluenesulfonic acid is neutralized to obtain a saturated aqueous solution of sodium p-toluenesulfonate, which is de-alkali-fused to produce p-cresol. Among them, alkali fusion is currently the batc...

AI Technical Summary

Problems solved by technology

Adopting this batch-type alkali fusion method to produce p-cresol single-pot reaction time is long (requires about 11 hours), and production efficiency is low

Since the alkali-fused material is in a high-temperature state for a long time, it is easy to coke and decompose, resulting in a low reaction yield, poor product quality, and increased difficulty in the post-processing of crude products.

The most important point is that since the aqueous solution of sodium p-toluenesulfonate is added in the reaction process, a large amount of phenol-containing water vapor will be produced in the production process, resulting in the loss of phenol products, and the direct discharge of phenol-containing water vapor will cause serious environmental pollution. , it is very difficult to handle

This also directly restricts the development of this industry

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