Diethyl maleate preparation method

A technology of diethyl maleate and maleic anhydride, which is applied in the field of preparation of diethyl maleate, can solve problems such as non-compliance with environmental protection requirements, environmental pollution, strong corrosion, etc., and achieve the goal of avoiding the problem of waste liquid discharge Effect

Inactive Publication Date: 2016-03-16
常州市松盛香料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Sulfuric acid is a strong inorganic acid with strong corrosiveness, can cause side reactions (such as oxidation, carbonization, addition), and is easy to cause environmental pollution, which does not meet current environmental protection requirements
Although cation exchange resin can overcome the shortcomings of sulfuric acid catalysis, the cost is relatively high.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1: the preparation method of diethyl maleate, concrete steps are as follows:

[0014] Add 5g maleic anhydride, 12g absolute ethanol, 0.3g acidic zeolite, 15ml hexanaphthene in the reaction vessel, install upper water separator, reflux condenser and thermometer on the reaction vessel, heat and carry out reflux water separation, react to no React for 25 minutes after the water droplets appear, stop heating, let the water layer out after cooling at room temperature for 30 minutes, wash the reaction solution with water, dry and distill, first distill out the previous fraction, and then collect the fraction at 216-220°C as the product.

Embodiment 2

[0015] Embodiment 2: the preparation method of diethyl maleate, concrete steps are as follows:

[0016] Add 2.5g of maleic anhydride, 6g of absolute ethanol, 0.15g of acidic zeolite, and 10ml of benzene into the reaction vessel, install an upper water separator, a reflux condenser and a thermometer on the reaction vessel, heat to reflux and separate water, and react until anhydrous React for 28 minutes after the beads appear, stop heating, let the water layer out after cooling at room temperature for 30 minutes, wash the reaction liquid with water, dry it and carry out distillation.

Embodiment 3

[0017] Embodiment 3: the preparation method of diethyl maleate, concrete steps are as follows:

[0018] Add 2.5g maleic anhydride, 6g absolute ethanol, 0.15g acidic zeolite, 10ml toluene to the reaction vessel, install an upper water separator, reflux condenser and thermometer on the reaction vessel, heat to reflux and divide water, and react until anhydrous React for 30 minutes after the beads appear, stop heating, let the water layer out after cooling at room temperature for 30 minutes, wash the reaction solution with water, dry and then carry out distillation.

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PUM

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Abstract

The present invention discloses a diethyl maleate preparation method, which concretely comprises: adding maleic anhydride, absolute alcohol, a solid acid catalyst and a water carrying agent to a reaction container, installing a water segregator, a reflux condensation pipe and a thermometer on the reaction container, heating to carry out reflux water separation, carrying out a reaction until no water drop appears, then continuously carrying out the reaction for 25-30 min, stopping the heating, carrying out room temperature cooling for 30 min, discharging the water layer, washing the reaction solution with water, drying, distilling, distilling out the front distillate, and collecting the distillate with a temperature of 216-220 DEG C so as to obtain the product. According to the present invention, the solid acid catalyst is used, such that the fed material conversion rate can be improved to more than or equal to 99.5% from the usual less than or equal to 95%; and the waste liquid emission problem caused by the addition of sodium carbonate to neutralize the excess acid in the liquid catalyst process can be avoided.

Description

technical field [0001] The invention relates to the technical field of preparation of organic matter, in particular to a preparation method of diethyl maleate. Background technique [0002] Diethyl maleate, also known as diethyl maleate, is mainly used in the synthesis of polymer monomers, pesticides (such as organophosphorus insecticides: malathion), medicines, spices, etc., commonly used The synthesis method is that maleic anhydride or maleic acid is esterified with ethanol under the catalysis of sulfuric acid or cation exchange resin. Sulfuric acid is a strong inorganic acid with strong corrosiveness, can cause side reactions (such as oxidation, carbonization, addition), and is easy to cause environmental pollution, which does not meet the current environmental protection requirements. Although cation exchange resin can overcome the shortcomings of sulfuric acid catalysis, but the cost is higher. The above two catalysts are used in the process of producing diethyl malea...

Claims

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Application Information

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IPC IPC(8): C07C67/08C07C69/60
Inventor 徐松浩
Owner 常州市松盛香料有限公司
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