Method for recycling ditrimethylolpropane

Abstract

The invention relates to a method for recycling ditrimethylolpropane, which is characterized by comprising the steps of: transferring heavy constituents at the bottom of a rectifying kettle in a refining procedure of trimethylolpropane, then filtering when hot in necessity, removing impurities with high crystallization point, transferring to a dynamic melt crystallizer, carrying out separation of crystallization, sweating and melting at a programmed temperature to ensure that other main impurities of the ditrimethylolpropane and the heavy constituents are separated; and carrying out refining of crystallization, sweating and melting on the collected rough ditrimethylolpropane at a programmed temperature to obtain a ditrimethylolpropane product with content of higher than 95 percent, which accords with the general requirements of industrial products. If higher requirements on platinum-cobalt chroma of not more than 15APHA are required in the color number of the products, the color is removed by combining the melt crystallization method with steps of absorbing and filtering, and the like. The method for recycling the ditrimethylolpropane has the advantages of simple operation, low cost, no need of high vacuum rectification, and low operation temperature.

Description

(1) Technical field

[0001] The invention relates to a method for recovering ditrimethylolpropane, in particular to a method for recovering ditrimethylolpropane from heavy components in the production of trimethylolpropane, and belongs to the technical field of recovery of organic chemical products. (2) Background technology

[0002] Ditrimethylolpropane is a by-product in the process of producing trimethylolpropane, which is formed by intermolecular dehydration of 2 molecules of trimethylolpropane. Its English name is ditrimethylolpropane, its English abbreviation is di-TMP, and its CAS number is 23235-61-2.

[0003] Japan's Mitsubishi Gas Chemical Co., Ltd. has obtained an authorized invention patent in China - "Preparation Method of Bis(trimethylolpropane)", which is translated into di-trimethylolpropane, and 2 molecules of trimethylolpropane Bis-TMP condensed with 1 molecule of formaldehyde is translated into ditrimethylolpropane. Since di-TMP has been recognized as dit...