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A kind of technological method for preparing maleic acid glycol ester

A technology of diol maleate and process method, which is applied in the preparation of carboxylate, chemical instruments and methods, preparation of organic compounds, etc., can solve problems such as incompatibility, prolong life, reduce equipment corrosion, The effect of increasing the reaction temperature and reaction pressure

Active Publication Date: 2022-05-10
宁波窦氏化学科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The technology described in this patent seems reasonable, but in fact there is a fatal problem: in the traditional process, dibutyl phthalate DBP (or dibutyl cyclohexanedioate) is used as the absorbent in the production process of maleic anhydride The biggest feature of DBP is that it can dissolve the maleic anhydride produced by the partial oxidation of n-butane and benzene, but it is incompatible with the by-product water
Therefore, it can be determined that the process described in its patent, producing dimethyl maleate DMM from maleic anhydride and methanol, and then selectively hydrogenating it is not feasible

Method used

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  • A kind of technological method for preparing maleic acid glycol ester
  • A kind of technological method for preparing maleic acid glycol ester
  • A kind of technological method for preparing maleic acid glycol ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment A1～A5

[0049] Examples A1-A5: Exploration of maleic anhydride / methanol molar ratio

[0050] In a 2.5L autoclave, add 4mol (392g) of maleic anhydride MAH, then add 6mol (192g) of methanol, after three times of 5kg nitrogen replacement, raise the reaction temperature to 110°C and keep stirring, and take samples at intervals , and detected by gas chromatography, after 8 hours of reaction, the composition of each component in the system does not change, which proves that the reaction has reached an equilibrium state. Under the same reaction conditions, the reaction proceeded three times. The difference was that the molar ratio of maleic anhydride and methanol changed from 1:1.2 to 1:1.5, 1:2, 1:2.5 and 1:3 respectively, that is, the added The amount of methanol is 4.8mol (153.6g), 58mol (256g), 10mol (320g) and 12mol (384g) respectively, the reaction process is the same, and finally all reach the equilibrium state, the above different MAH / methanol ratio and the equilibrium composition of...

Embodiment B1～B5

[0054] Examples B1-B5: Exploration of the first stage esterification reaction conditions

[0055] The first step of the esterification reaction is carried out in a shell-side Φ108X4 (SS304), tube-side 7 pieces of Φ25X3 (SS316L) tube-and-tube reactors, and the tube-side is filled with Φ5X5 ceramic Raschig rings (bulk density 1.2, pores Rate 0.46), the shell side uses circulating heat transfer oil with a fixed temperature as the heat transfer medium; the maleic anhydride melts and keeps the temperature at 90°C, the pump head and pipeline of the feed pump are kept at 110°C with electric heat tracing; methanol is kept at 50°C, The methanol pump pump head and pipeline are also kept at 50°C; the pressure of the two product collection tanks of the product collection system is maintained at 1.0Mpa in the mode of nitrogen back pressure, so that the reaction can be carried out continuously, and the molar ratio of the maleic anhydride and methanol of the feed is 1: 2.5; the reactions wer...

Embodiment C1

[0058] Embodiment C1: the synthesis of dimethyl maleate DMM

[0059] (1) first-stage esterification reaction: with embodiment B3;

[0060] (2) Flash distillation: 4000 g of the reaction mixture under the condition of 110°C-4h obtained in the previous step is carried out to flash distillation; the used flash distillation column is a continuous feed in the middle, with a total length of one meter and an inner diameter of It is a 25mm glass rectification tower with Φ5 titanium ring wire mesh packing inside. There is a 2500ml three-neck flask at the bottom of the flash rectification tower, which is heated by an oil bath; the entire flash rectification tower is equipped with upper reflux and extraction, The middle feed and the bottom outlet are both fed and discharged by a peristaltic pump equipped with a silicone tube; the entire flash distillation column is operated under a slight positive pressure, and the temperature of the tower body is 80-120 ° C. The three-necked flask at th...

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Abstract

The invention discloses a process for preparing diol maleate, which is characterized in that it includes the following steps: (1) performing pre-esterification reaction with maleic anhydride and lower fatty alcohol in a pre-esterification reactor to obtain the corresponding A mixture of water, alcohol, maleic acid monoalcohol ester, maleic acid diol ester and a small amount of maleic anhydride; (2) The reaction mixture produced by the pre-esterification reaction is first flashed and rectified, and then catalyzed by the acidic resin And corresponding lower aliphatic alcohol completes esterification by reactive distillation, obtains required diol maleate. Compared with the prior art, the process for preparing diol maleate of the present invention has less process pollution, low energy consumption and high product yield, and the whole process is operated smoothly, avoiding overheating on the reaction distillation column tray , prolonging the service life of the catalyst.

Description

technical field [0001] The invention relates to the technical field of synthesis of fine chemicals and polymer monomers, in particular to a synthesis process and route for preparing diol maleate. Background technique [0002] The most representative maleate glycol esters are dimethyl maleate (Dimethyl Maleate, DMM), diethyl maleate (Diethyl Maleate, DEM) and dipropyl maleate (Dipropyl Maleate, DPM). ), the former two are important fine chemical raw materials. The production processes and methods of other diol maleate esters are basically similar to the former two, and the existing articles and patents basically use DMM and DEM as representatives to introduce their process routes and methods. Dimethyl maleate (DMM) is a colorless viscous liquid, boiling point (1.0bar) 200.4°C, melting point: 19.0°C, relative density (25°C) 1.1462g / cm 3 , is an important chemical raw material for the production of paints, coatings, adhesives, insecticides, water purifiers, optical materials,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C69/60C07C67/00C07C67/08
CPCC07C67/08C07C67/00C07C69/60Y02P20/10
Inventor 窦和瑞
Owner 宁波窦氏化学科技有限公司
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