Method for preparing anhydrous perpropionic acid

Abstract

The invention discloses a method for preparing anhydrous perpropionic acid free from a catalyst. 4-5 reactive distillation columns connected in series and a distillation rectification column are adopted, hydrogen peroxide, the catalyst, a light component and phosphate ester are fed, subjected to pre-mixing and fed into column bodies of the 4-5 continuous reactive distillation columns through pumpsin sequence, reactive distillation is conducted in the reactive distillation columns, column bottom liquid of the last reactive distillation column enters the distillation rectification column, the anhydrous perpropionic acid free from the catalyst is collected on the column top of the distillation rectification column, and the catalyst and phosphate ester contained in the column bottom are fed back to the first reactive distillation column for recycle. By means of the method for preparing the anhydrous perpropionic acid free from the catalyst, continuous anhydrous perpropionic acid preparation is achieved, moreover, the catalyst is recycled in a system, and synthesis of epsilon-caprolactone is not affected.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to a method for preparing anhydrous peroxypropionic acid, in particular to a method for preparing anhydrous peroxypropionic acid by using series reaction rectification towers. Background technique [0002] ε-caprolactone (ε-CL) is a versatile chemical intermediate, mainly used as a monomer for high-performance polymer materials. Polycaprolactone (PCL) is obtained by self-polymerization of ε-caprolactone. PCL has good thermoplasticity and molding processability, and can be made into environmentally friendly plastic products for various purposes, and can also be made into biodegradable biomedical materials; ε - Caprolactone is triggered by polyol to obtain polycaprolactone polyol, polycaprolactone polyol reacts with diisocyanate to prepare high-performance material polycaprolactone polyurethane, which is widely used as a special polyurethane in synthetic leather, Automotive co...

AI Technical Summary

Problems solved by technology

The technology needs to be improved in terms of safety, and there is no industrialization

[0009] In 2013, Jiangsu Feixiang Chemical Co., Ltd. cooperated with Sun Yat-sen University to use magnesium or tin porphyrin complexes as catalysts to react with benzaldehyde through air or oxygen in ester solvents. The conversion rate of cyclohexanone and ε-hexyl The yield of lactone is greater than 95%, but the by-product benzoic acid and caprolactone are difficult to separate

[0012] In the process of preparing ε-caprolactone by the indirect method of hydrogen peroxide, firstly, peroxycarboxylic acid is prepared. Since hydrogen peroxide contains a large amount of water, water is also generated during the preparation process, so the peroxycarboxylic acid solution contains a large amount of water. In order to reduce the impact on the oxidation reaction of cyclohexanone, it is required that the prepared peroxycarboxylic acid solution does not contain water. Generally, an organic solvent is selected to remove the moisture in the peroxycarboxylic acid solution through azeotropic distillation, but due to the azeotropic distillation During the process, the evaporated azeotropic solvent has a certain compatibility with water, and the weight content of saturated water generally reaches 2-3%. In this way, when preparing anhydrous peroxycarboxylic acid solution, the reflux ratio of rectification separation is very high, and the product can The consumption is very high. To prepare one ton of ε-caprolactone product, it needs to consume more than 10 tons of steam in the process of preparing anhydrous peroxycarboxylic acid, and also consumes a large amount of circulating cooling water

Not only that, but also in order to remove the moisture in the peroxycarboxylic acid solution by azeotropic rectification, the rectification time required is very long, and generally a batch reaction needs rectification time 24 hours, which seriously reduces the production capacity of the device