Preparation method of 1,4-dioxane

Abstract

The invention discloses a preparation method of 1,4-dioxane. The method comprises using a solid super acid resin as a catalyst for a catalytic reaction with diglycol, then using isopropyl ether to extract and dehydrate crude products in a high-efficiency extraction tower, and treating waste water by using a cation resin tower. The method successfully overcomes many insufficiencies of a tradition technology, brings revolutionary advances for production of the 1,4-dioxane, and realizes a long-term pollution-free production of the products.

Description

technical field [0001] The invention relates to a preparation method of 1,4-dioxane, which belongs to the technical field of chemical industry. Background technique [0002] 1,4-Dioxane is used as a solvent, reaction medium, and extraction agent in the manufacture of special fine chemicals such as medicine, cosmetics, and spices, as well as in scientific research. Molecular formula C 4 h 8 o 2 , molecular weight 88.11, melting point 11.8 ℃, boiling point 101.3 ℃, colorless and transparent liquid at room temperature. The production of 1,4-dioxane, especially in China, used a traditional production process before, that is, using diethylene glycol to carry out intramolecular dehydration synthesis in a reactor under the catalysis of 98% concentrated sulfuric acid . The main process includes: synthesis (that is, use diethylene glycol under negative pressure conditions to heat up to 150 ° C under the catalysis of 98% concentrated sulfuric acid for intramolecular dehydration);...

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Problems solved by technology

[0005] ② During the synthesis reaction, a large amount of by-product tar is produced due to the high reaction temperature, and the reactor needs to be cleaned after the tar has accumulated to a certain extent, so the continuous production of this product cannot be realized;

[0006] ③ Sulfuric acid is used as a catalyst in the synthesis reaction process, and the selectivity of the catalyst is relatively poor, and about 3%-5% of by-product methyl pentacyclic rings are produced in the reaction process;

[0007] ④ A large amount of caustic soda is used in the dehydration process. Although it plays a role in separation, a large amount of waste water containing about 20% sodium hydroxide is produced. At the same time, this waste water contains a large amount of tar produced during the synthesis reaction process, and the waste water treatment is extremely difficult.

[0008] In the process of synthesis reaction and dehydration, sulfuric acid is used as a catalyst and caustic soda to produce a large amount of acid waste and alkaline tar-containing wastewater, which causes environmental pollution or brings great environmental pressure and increases treatment costs.

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