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A continuous production process for synthesizing hexahydrophthalic anhydride in a mixed solvent

A mixed solvent and hexahydrophthalic anhydride technology, applied in the direction of organic chemistry, can solve the problems of low production efficiency, difficult solvent removal, high impurity content, etc., and achieve the effects of improved production efficiency, difficult separation and removal, and high product purity

Active Publication Date: 2021-02-05
PUYANG SHENGYUAN ENERGY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, most of the domestically reported patents use the melting batch method to prepare hexahydrophthalic anhydride, and the production efficiency is low. However, the domestic continuous method of hexahydrophthalic anhydride uses a single solvent, which is difficult to remove and has high impurity content.

Method used

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  • A continuous production process for synthesizing hexahydrophthalic anhydride in a mixed solvent

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Embodiment Construction

[0023] In order for those skilled in the art to better understand the technical solutions provided by the present invention, the following will be further elaborated in conjunction with specific embodiments.

[0024] figure 1 For the process flow diagram of the present invention, firstly, the catalyst is fixed on the fixed-bed reactor, and the NiO / SiO2 catalyst is loaded on the fixed-bed reactor 5 . First replace the reaction system with nitrogen to make the oxygen content lower than 0.2% (volume), then switch to hydrogen for catalyst reduction, control the volume space velocity of hydrogen feed to 2000h-1, reactor temperature 130°C, pressure 3.0Mpa, reduction 24h .

[0025] Carry out hydrogenation reaction then, THF and hexanaphthene are formulated as mixed solvent in solvent tank by volume ratio 5:1, tetrahydrophthalic anhydride and mixed solvent are dropped into batching tank 1 by mass ratio 1:4, pass through the first circulation pump 2 into the fixed-bed reactor 5 equip...

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Abstract

The invention provides a continuous production process for synthesizing hexahydrophthalic anhydride in a mixed solvent. According to the invention, the process adopts a fixed bed continuous reaction method; crude hexahydrophthalic anhydride is prepared through hydrogenation by using a mixture composed of tetrahydrofuran and cyclohexane as a solvent and tetrahydrophthalic anhydride and hydrogen asraw materials under certain pressure and temperature conditions; a hexahydrophthalic anhydride product is obtained through vacuum flashing and continuous scraper type film evaporation processes; excess hydrogen and the mixed solvent are respectively recovered and reutilized through a gas-liquid separation tank, a vacuum flashing tower and a film evaporator; the consumed amounts of the hydrogen andthe mixed solvent are only required to supplemented; and recovery of atmosphere gas and a mixed solution is realized. The continuous production process applied to the hexahydrophthalic anhydride provided by the invention can realize continuous feeding and discharging and has the advantages of few side reactions, high product stability and high production efficiency.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a continuous production process for synthesizing hexahydrophthalic anhydride in a mixed solvent. Background technique [0002] The full name of hexahydrophthalic anhydride is hexahydrophthalic anhydride, white to off-white crystal, low melting point solid, soluble in tetrahydrofuran, benzene, acetone and other solvents. Hexahydrophthalic anhydride is an indispensable raw material for the production of polyester coatings. Using hexahydrophthalic anhydride instead of aromatic polyacids to produce amino alkyds, polyurethane paints, powder coatings, etc. can significantly improve the vividness and gloss of the coatings. At the same time, hexahydrophthalic anhydride Phthalic anhydride can also be used as curing agent, adhesive and plasticizer of epoxy resin. [0003] Catalytic hydrogenation of tetrahydrophthalic anhydride to prepare hexahydrophthalic anhydride is a common...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D307/89
CPCC07D307/89
Inventor 张全喜张文水王广泉
Owner PUYANG SHENGYUAN ENERGY TECH
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