Method for synthesizing crotonic acid by using byproduct of croton aldehyde

A technology for by-product crotonaldehyde and crotonaldehyde, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate, etc., can solve the problem of complex pretreatment methods of salting and rectification, corrosive equipment, crotonic acid collection, etc. Low efficiency and other problems, to achieve the effect of simple pretreatment method, high recovery rate and high reactivity

Inactive Publication Date: 2007-07-25
SINOPEC YANGZI PETROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The yield of crotonic acid synthesized by this method is low, and the salting and rectifying pretreatment method used is complicated and corrosive to equipment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A 1000ml three-necked flask with a diameter of 25mm was added to a 1000ml three-necked flask with a crotonaldehyde content of 23.37%. The by-product crotonaldehyde of the acetaldehyde plant was distilled without reflux until the temperature at the top of the column reached 65°C and stopped. , the still liquid was analyzed by gas chromatography, the mass content of crotonaldehyde was 45.75%, and the recovery rate of crotonaldehyde was 90.79%.

Embodiment 2

[0022] A 1000ml three-necked flask with a diameter of 25mm was added to a 1000ml three-necked flask with a crotonaldehyde content of 33.54%. The by-product crotonaldehyde was added to the acetaldehyde plant with a crotonaldehyde content of 33.54%. The distillation was carried out without reflux until the temperature at the top of the column reached 65°C, and the remaining liquid in the flask weighed 443g. , the still liquid was analyzed by gas chromatography, the mass content of crotonaldehyde was 55.01%, and the recovery rate of crotonaldehyde was 90.82%.

Embodiment 3

[0024] A 1000ml three-necked flask with a diameter of 25mm was added to a 1000ml three-necked flask with a crotonaldehyde content of 23.37%, and the by-product crotonaldehyde was added to the acetaldehyde device with a crotonaldehyde content of 23.37%, and the distillation was carried out without reflux until the temperature at the top of the column reached 25°C and stopped, and the remaining kettle liquid in the flask weighed 698g. , the still liquid was analyzed by gas chromatography, the mass content of crotonaldehyde was 26.50%, and the recovery rate of crotonaldehyde was 98.95%.

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Abstract

This invention relates to a method for synthesizing crotonic acid from crotonaldehyde byproduct. The method comprises: distilling 20-40% crotonaldehyde byproduct by controlling the boiling point of the distillate on the top of the column at 25-65 deg.C to remove light components and obtain 45-60% crotonaldehyde in the solution in distillation kettle, adopting the solution in distillation kettle as the raw material, acetone, acetic acid, benzene or toluene as the solvent, phosphomolybdic acid as the main catalyst, and V2O5 as the cocatalyst, and reacting at 30-100 deg.C and 0.3-0.9 MPa in the presence of O2, separating the catalyst, distilling to remove the solvent, and recrystallizing with deionized water for twice to obtain crotonic acid with a purity higher than 99%. Phosphomolybdic acid can be supported by such carriers as active carbon, SiO2, gamma-Al2O3 or molecular sieve. Therefore, the catalyst can be separated from the reaction solution by filtration, and dried in air at 120 deg.C for recycling. The method has such advantages as simple process and high crotonic acid yield.

Description

technical field [0001] The invention relates to a comprehensive utilization method of chemical by-products, in particular to a method for synthesizing crotonic acid by utilizing by-product crotonaldehyde. Background technique [0002] Acetaldehyde is an important raw material for the synthesis of acetic acid, pyridine, pentaerythritol and sorbic acid. Its main industrial production methods include ethanol oxidation and ethylene direct oxidation. Due to the active nature of acetaldehyde, in the production process of acetaldehyde, two molecules of acetaldehyde undergo condensation and dehydration reaction to generate crotonaldehyde, and the by-product crotonaldehyde is extracted from the side line at the 8th plate in the upper part of the acetaldehyde refining tower. The chemical components include crotonaldehyde, acetaldehyde, water and triacetaldehyde, etc. Crotonaldehyde and water also form a binary azeotrope, and crotonaldehyde is chemically active and easy to polymerize, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/235C07C57/08B01J27/199
Inventor 乔旭李维新汤吉海温从科崔咪芬秦建元赵宝明
Owner SINOPEC YANGZI PETROCHEM
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