Preparation process of 2,2,4-trimethyl-1,3-pentanediol mono-sio butyrate

Abstract

The invention relates to a preparation process of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. Under the action, the isobutyraldehyde first undergoes a condensation reaction under low temperature conditions, and the reaction temperature is 10-60 °C. Then, the temperature is directly heated, the reaction temperature of the second stage is 60-150 DEG C, and the reaction pressure should keep the aldehyde reacting in the liquid phase state. The unreacted isobutyraldehyde is recovered from the second-stage reaction mixture and subjected to vacuum distillation to obtain a diol monoester product with a purity of over 98%. The catalysts include alkali or alkaline earth metal hydroxides, alkaline earth metal oxides, alkali or alkaline earth metal salts, organotin, stannous oxide or a mixture of two or more thereof. The process adopts two-stage reaction, and the intermediate process does not require phase separation and washing, not only the amount of waste water treatment is small, but also the generation amount of the main by-product 2,2,4-trimethyl-1,3-pentanediol is also very small, Its maximum content is 8%, which directly simplifies the separation process and makes the whole process simple and feasible.

Description

1. Technical field [0001] The invention relates to the preparation process of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. 2. Background technology [0002] As we all know, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate is a water-insoluble high-boiling diol ester, which has a wide range of applications and can be used directly or indirectly as a coating aid. Agents, lubricants, insecticides, solvents, herbicides, polyester resins and plastic additives, etc. In recent years, with the increasingly stringent environmental protection regulations, this product has become a superior coating film-forming agent in water-based architectural coating environmental labeling products (ie green coatings) with synthetic resin emulsion as the main film-forming substance. [0003] There are many synthetic methods for the preparation of 1,3-diols and their monoester products such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate from the corresponding aldehydes. Most of these methods...

AI Technical Summary

Problems solved by technology

[0007] Above-mentioned technique has many shortcomings, especially the technique isobutyraldehyde conversion rate that German patent DE 3 403 696 introduces is low, forms a large amount of by-products in the reaction, and technological process is complicated, comprises high pressure and two kinds of different types of catalyst systems, product yield rate up to only 40%

The technical process introduced by CN 1098712A requires two static water separation and washing processes, and there are many preparation steps. Although the reaction yield can reach 69%, the reaction selectivity is low, and there is still a considerable amount of 2,2,4-trimethyl - Formation of 1,3-pentanediol by-product

In the preparation process described in WO 98 / 24752, the conversion rate of isobutyraldehyde in the first step is 60-95%, and the second step is 2,6-diisopropyl-5,5-dimethyl-1,3-dioxa-4 - The alcohol conversion rate is 70-95%, and the content of the by-product diol can be controlled within 10%, but in order to improve the product selectivity, the reaction time is extended to more than 24h; there are many intermediate steps in the reaction, and 2-times of water washing and layering are required steps, while requiring two different catalyst systems

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