Process for producing neopentyl glycol by continuous catalytic hydrogenation

Abstract

The invention discloses a process for producing neopentyl glycol by continuous catalytic hydrogenation, which solves the problems of complex operation, long flow and high investment and cost in the traditional neopentyl glycol production process, and adopts the technical scheme that a hydroxypivalaldehyde hydrogenation raw material and hydrogen are directly fed into a heat transfer hydrogenation reactor filled with a hydrogenation catalyst for reaction; a reaction product is led out from the bottom of the reactor and sent into a hydrogenation outlet separator for gas-liquid separation, one part of the separated gas returns to an inlet of the heat transfer hydrogenation reactor for cyclic utilization, and the other part of the separated gas is exhausted as purge gas; the separated liquid istreated through a light component removal tower and a heavy component removal tower to obtain a refined neopentyl glycol product; and the hydrogen-aldehyde molar ratio of the hydrogen to the hydroxypivalaldehyde hydrogenation raw material is (1.1-3): 1. The method has the advantages of simple process, short flow, mild reaction conditions, no need of additional addition of an organic solvent or separation and refining, energy saving, consumption reduction, low production cost and investment cost, and high yield.

Description

technical field [0001] The invention relates to the field of fine chemical industry, in particular to a process for continuously catalytic hydrogenation to produce neopentyl glycol. Background technique [0002] As an important diol product, neopentyl glycol (NPG) is currently mainly used in the production of polyester resins for powder coatings and saturated polyester resins for coil steel (accounting for about 70% of the consumption of neopentyl glycol ), unsaturated polyester resin and alkyd resin chemical products. [0003] The production method of neopentyl glycol in industry usually uses isobutyraldehyde and formaldehyde as raw materials, and prepares neopentyl glycol through hydroxypivalaldehyde (2,2-dimethyl 3-hydroxypropanal) intermediate. According to the catalytic process used to convert hydroxypivalaldehyde into neopentyl glycol, it can be divided into two types: formaldehyde disproportionation method and catalytic hydrogenation method. Among them, the formaldeh...

AI Technical Summary

Problems solved by technology

According to the catalytic process used to convert hydroxypivalaldehyde into neopentyl glycol, it can be divided into two types: formaldehyde disproportionation method and catalytic hydrogenation method. Among them, the formaldehyde disproportionation method uses a strong alkali catalyst, which is characterized by mild process conditions and simple operation. Large consumption will form a large amount of by-product formate, which is difficult to separate, resulting in poor product quality, more waste water discharge, and great pressure on environmental protection

At present, the production technology of neopentyl glycol at home and abroad has been gradually replaced by the catalytic hydrogenation method. This process has low raw material consumption, outstanding environmental protection advantages, high product quality, and is suitable for deep processing of downstream products. The disadvantage is that the operation is relatively complicated and uses medium and high pressure. Hydrogenation equipment, equipment investment is relatively high

[0004] In the process of synthesizing hydroxypivalaldehyde, side reactions will inevitably occur, such as the condensation of hydroxypivalaldehyde itself into hydroxypivalic acid neopentyl glycol monoester, Neopentyl glycol acetal compounds, etc. These by-products are relatively stable and difficult to decompose, which may easily lead to incomplete hydrogenation and affect the yield and quality of the product

CN108017510A discloses a method for preparing hydroxypivalaldehyde from epoxy isobutane, but the catalyst system is complicated and needs to be separated and refined from raw materials

The above HPA hydrogenation neopentyl glycol catalysts or processes all need to add an organic solvent or recycled neopentyl glycol as a dilution solvent to HPA, and at the same time need to refine HPA before participating in the subsequent hydrogenation reaction, resulting in equipment investment and operation Costs are higher

However, there are few research reports on the optimization of neopentyl glycol production process from the perspective of HPA hydrogenation reactor or its supporting process flow in the published patents

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