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Production process of dimethyl isophthalate

A technology of diethyl isophthalate and isophthalic acid, which is applied in the production field of diethyl isophthalate, can solve the problems of high pressure resistance performance of equipment, high production cost and high reaction temperature, and achieve durable Low pressure performance requirements, low production cost, and low reaction temperature

Inactive Publication Date: 2008-11-19
夏旭明
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the reaction temperature is high, and it must be carried out at a temperature of 230°C-300°C. High reaction temperature, on the one hand, increases energy consumption in production, and on the other hand, requires high pressure resistance of the equipment. The equipment investment is large, so the production cost is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] A kind of production method of diethyl isophthalate, comprises the steps:

[0017] 1. Mix isophthalic acid, ethanol and concentrated sulfuric acid according to the molar ratio of 1:3.7:0.011, put them into the reaction kettle, and stir fully and evenly;

[0018] 2. Heat the reactor with steam. When the temperature of the reactor rises to 140°C and the pressure rises to 0.4Mpa, keep the pressure for 1 hour;

[0019] 3. Distill alcohol. After the pressure keeping is completed, open the alcohol distillation valve connected to the reactor to distill the product in the reactor. The end temperature of alcohol distillation is 150°C;

[0020] 4. Alcohol feed, after the distillation, add ethanol to the reactor; during the process of alcohol feed, the pressure in the reactor is kept at normal pressure, and the temperature of the reactor is kept at ≥ 110°C; when the acid value of the product in the reactor is reduced When it is ≤5mgKOH / g, stop feeding alcohol;

[0021] 5. Pressu...

Embodiment 2

[0025] 1. Mix isophthalic acid, ethanol and concentrated sulfuric acid according to the molar ratio of 1:4.0:0.014, put them into the reaction kettle, and stir fully and evenly;

[0026] 2. Heat the reactor with steam. When the temperature of the reactor rises to 130°C and the pressure rises to 0.4Mpa, keep the pressure for 1 hour;

[0027] 3. Distill alcohol. After the pressure keeping is completed, open the alcohol distillation valve connected to the reactor to distill the product in the reactor. The end temperature of alcohol distillation is 160°C;

[0028] 4. Alcohol feed, after the distillation, add ethanol to the reactor; during the process of alcohol feed, the pressure in the reactor is kept at normal pressure, and the temperature of the reactor is kept at ≥ 110°C; when the acid value of the product in the reactor is reduced When it is ≤5mgKOH / g, stop feeding alcohol;

[0029] 5. Pressure relief and temperature reduction, so that the temperature of the reactor can be r...

Embodiment 3

[0033] A kind of production method of diethyl isophthalate, comprises the steps:

[0034] 1. Mix isophthalic acid, ethanol and concentrated sulfuric acid according to the molar ratio of 1:3.8:0.013, put them into the reaction kettle, and stir fully and evenly;

[0035] 2. Heat the reactor with steam. When the temperature of the reactor rises to 135°C and the pressure rises to 0.4Mpa, keep the pressure for 1 hour;

[0036] 3. Distill alcohol. After the pressure keeping is completed, open the alcohol distillation valve connected to the reactor to distill the product in the reactor. The end temperature of alcohol distillation is 155°C;

[0037] 4. Alcohol feed, after the distillation, add ethanol to the reactor; during the process of alcohol feed, the pressure in the reactor is kept at normal pressure, and the temperature of the reactor is kept at ≥ 110°C; when the acid value of the product in the reactor is reduced When it is ≤5mgKOH / g, stop feeding alcohol;

[0038] 5. Pressu...

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PUM

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Abstract

The invention relates to a method for producing diethyl isophthalate. The method is characterized in that: m-phthalic acid and ethanol as raw material and concentrated sulfuric acid as a catalyzer are mixed according to a molar ratio of 1 to 3.7-4.0 to 0.011-0.014, thrown into a reaction kettle, fully and evenly stirred, then subject to heating, pressure maintaining, distillation, neutralization and rectification, thereby obtaining a product of the diethyl isophthalate. In the invention, the temperature of the whole production process is less than or equal to 170 DEG C; the method has low reaction temperature and short esterification time, thereby reducing energy consumption, saving energy and having low requirement on the pressure resistance of equipment and low production cost.

Description

technical field [0001] The present invention relates to a kind of production method of diethyl isophthalate. Background technique [0002] The method for preparing diethyl isophthalate is involved in the patent No. US3935238 "Preparation of phthalic acid". The production method of the lower ester of isophthalic acid disclosed in this patent document includes the contact between m-phenylenediamine and a lower alcohol (including methanol and ethanol) at a temperature of 230°C-300°C, and the catalyst used is silicon, titanium , lead, zirconium, thorium basic oxides, the amount of catalyst is not less than 0.2%. The disadvantage of this method is that the reaction temperature is high, and it must be carried out at a temperature of 230°C-300°C. High reaction temperature, on the one hand, increases energy consumption in production, and on the other hand, requires high pressure resistance of the equipment. The equipment investment is large, so the production cost is high. Conte...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/80C07C67/08
Inventor 夏旭明
Owner 夏旭明
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