Method for producing vinyl acetate

A production method and vinyl acetate technology are applied in chemical instruments and methods, preparation of carboxylate, preparation of organic compounds, etc., and can solve the problems of unfavorable economy, low conversion rate of ethylene per pass, and high reaction temperature, and reduce production costs, The effect of increasing the explosion limit and lowering the reaction temperature

Inactive Publication Date: 2012-03-21
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the increase of oxygen concentration in the system is limited by the explosion limit, and it is often controlled in a lower range (≤6%mol%) in actual production.
Although lower oxygen concentration has higher operational safety, but the reaction temperature is higher, the single-pass conversion rate of ethylene is lower, and it is economically unfavorable

Method used

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  • Method for producing vinyl acetate
  • Method for producing vinyl acetate

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Experimental program
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Effect test

Embodiment 1

[0019] In the production of vinyl acetate, oxygen is mixed with the circulating gas containing ethylene and acetic acid through the oxygen mixer 4, and the mixed gas enters the reactor 1 for reaction. After the reaction, the high-temperature reaction gas is condensed through the condensation system 2, and the uncondensed gas phase is passed through the circulating gas compressor. 3. Cycle after boosting. Nitrogen is added in the circulating gas, and the nitrogen concentration of the control reactor inlet is 30% (mol%), and the oxygen concentration of the reactor inlet is increased to 12% (mol%) this moment, and at the initial stage of catalyst use, the reaction temperature is 110 ° C; In the mid-use period, the reaction temperature is 150°C; in the late use of the catalyst, the reaction temperature is 180°C. 20°C lower than the original process. Vinyl acetate selectivity was 96%, a 3% improvement.

Embodiment 2

[0021] In the production of vinyl acetate, oxygen is mixed with the circulating gas containing ethylene and acetic acid through the oxygen mixer 4, and the mixed gas enters the reactor 1 for reaction. After the reaction, the high-temperature reaction gas is condensed through the condensation system 2, and the uncondensed gas phase is passed through the circulating gas compressor. 3. Cycle after boosting. Nitrogen is added in the circulating gas, and the nitrogen concentration of the control reactor inlet is 15% (mol%), and the oxygen concentration of the reactor inlet is increased to 11.4% (mol%) at this moment, and at the initial stage of catalyst use, the reaction temperature is 120 ° C; In the mid-use period, the reaction temperature is 160°C; in the late use period of the catalyst, the reaction temperature is 190°C. 10°C lower than the original process. Vinyl acetate selectivity was 95%, a 2% improvement.

Embodiment 3

[0023] In the production of vinyl acetate, oxygen is mixed with the circulating gas containing ethylene and acetic acid through the oxygen mixer 4, and the mixed gas enters the reactor 1 for reaction. After the reaction, the high-temperature reaction gas is condensed through the condensation system 2, and the uncondensed gas phase is passed through the circulating gas compressor. 3. Cycle after boosting. Nitrogen is added in the circulating gas, and the nitrogen concentration of the control reactor inlet is 8% (mol%), and this moment, the oxygen concentration of the reactor inlet is increased to 10.5% (mol%), and at the initial stage of catalyst use, the reaction temperature is 125°C; In the mid-use period, the reaction temperature is 165°C; in the late use period of the catalyst, the reaction temperature is 195°C. 5°C lower than the original process. The vinyl acetate selectivity was 93.5%, an increase of 0.5%.

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Abstract

The invention discloses a method for producing vinyl acetate. Inert gas is added into recycle gas to improve the explosion limit of oxygen, enlarge a stable area of a reaction system and improve the oxygen concentration of the reaction system, so that the reaction temperature is reduced, the service life of a catalyst is prolonged, and the selectivity of the vinyl acetate is improved. The inert gas is nitrogen or a mixture of nitrogen and methane. The concentration of the inert gas at the inlet of a reactor is 8 to 30 mol percent, and the molar concentration of the oxygen at the inlet of the reactor is 10.5 to 12 mol percent.

Description

technical field [0001] The invention relates to a method for producing vinyl acetate. The method expands the stable area by adding inert gas into the circulating gas, increases the oxygen concentration at the reactor inlet, reduces the reaction temperature, prolongs the service life of the catalyst, improves the selectivity of vinyl acetate, reduces production costs, and improves the market competition of vinyl acetate products force. Background technique [0002] Vinyl acetate (VAC) is an important organic chemical raw material. Polyvinyl alcohol (PVA), vinyl acetate-ethylene copolymer (EVA), polyvinyl acetate (PVAC), Derivatives such as vinyl acetate-vinyl chloride copolymer (EVC). These derivatives have a wide range of uses, and are generally used in adhesives, sizing agents for paper or fabrics, paints, inks, leather processing, emulsifiers, water-soluble films, and soil conditioners. Vinyl acetate is used as an intermediate, and with the expansion of the application ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/15C07C67/05
CPCC07C67/05C07C69/15
Inventor 张敏华董秀芹陶敏莉刘成欧阳胜利姜浩锡马静李桂明
Owner TIANJIN UNIV
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