CS248558B1 - The process for the production of vinyl acetate acetic acid - Google Patents

Abstract

The essence of the solution is a method of producing vinyl acetates using recycles in the preparation of the synthesis mixture. In this process, acetic acid vapor is sucked from the regenerated stage, where acetic acid is fed as reflux, mixed with the total recirculating acetylene, and the mixture thus prepared with a temperature above 60 C is divided into individual streams for preheating, or rather into reaction stages 99·

Description

(54)

ONDRUS IMBICH ing. CSc., PRIBVIDZA, ΡΔΡΡ JOZBF ing., BRATISLAVA

Process for producing acetic acid vinyl acetate

The essence of the solution is a process for the production of vinyl esters of acetic acid using reoyls in the preparation of the synthesis mixture.

In this process, the acetic acid vapor is recovered from the regenerated stage, where acetic acid is supplied as reflux, mixed with total re-circulated acetylene, and the mixture thus prepared at a temperature above 60 ° C is divided into individual streams for preheating or heating. to reaction stages 99 ·

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The present invention relates to a process for the preparation of vinyl acetate or acetic acid 8 by using cycles in the preparation of a synthesis mixture.

The vapor phase production of vinylacatate from acetic acid and acetylene is accomplished by preparing a synthesis mixture of acetylan and acetic acid vapors in a molar ratio of acetylan to acetic acid of 4 to 12 so that the measured liquid amount of acetic acid is evaporated and mixed with the necessary amount. · The synthesis mixture for each reactor is preheated up to the reaction temperature and next to the reactor is filled with catalyst / zinc acetate on activated carbon / · Industrial reactions lead to 50 to 60% conversion of acetic acid to vinyl acetate * condensation of the reaction product returns acetylene · Unreacted acetic acid is recovered and returned as a liquid back to vinyl acetate production.

The acetylene / acetic acid molar ratio is one of the decisive parameters for optimal and efficient reactor operation · The current process of preparing the synthesis mixture in vinyl acetate production is based on the fact that for individual reactors recycled acetylene is divided into the required number of streams into individual reactors and measured liquid quantities of acetic acid (which is a mixture of regenerated and pure acetic acid) is added to the vapor stream of acetylan * in vapor to give a synthesis mixture with the necessary molar porter acetylene / acetic acid *

This process of preparing the synthesis mixture is energy intensive * since unreacted acetic acid needs to be regenerated ** condensed and evaporated again.

Acetic acid vapors from the regeneration stage can be dosed practically accurately into individual streams of recirculating acetylan due to the unmanageability of the control systems in the dd248 8S8 and due to the condensation of acetic acid vapor in the control elements.

and

The above-mentioned drawbacks are eliminated by the method of production of vinyl acetate by catalytic synthesis from acetylene and acetic acid, and unreacted raw materials are applied for the preparation of the reaction mixture, which is carried out by adding fresh liquid acetic acid to the vapor phase of raganerated acetic acid. 1 to 2 and 2, wherein the subsequent mixing with 8 recycled acetylene and fresh acetylene is fed to the recycled acetylene or to the individual process streams of the synthesis mixture in an amount corresponding to the total loss of amount of cracking product formed and technological losses, at 60 ° C and the synthesis mixture thus prepared was put into process streams and in addition to preheating to individual reaction systems ·

The residual product from the distillation of vinyl acetate is fed to the recovery column where acetic acid is fed as reflux as the amount of acetic acid consumed in the production of vinyl acetate · Acetic acid vapors leave the recovery column head via a heat exchanger to the mixer. recirculating acetylene recirculating blower after condensation in the condensation sector and after degassing by piping and fresh acetylene inlet through the heat exchanger The thermometer sensor maintains a constant recirculating acetylene temperature above 60 ° C by venting the control valve. The resulting mixture of acetylene and acetic acid springs from the mixer is passed through a line to the heat exchanger through the control valves and flow restrictors from the individual reactors. to circulating blower ·

Example 1

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For the production of 1350 kg / h of vinyl acetate ea, the pipeline feeds pure acetic acid in an amount of 1,050 kg / h as a reflux to the recovery column and through the pipeline the residual distillation product from the tall product of 1,350 kg / h of vinyl acetate. of acetic acid through a heat exchanger to a dipper, where it is mixed with 4,500 m / h of recirculating acetylene * The obtained eynthesis mixture was supplied from the pipeline by ragulation valves as needed for individual reactors ·

Claims (1)

SUMMARY OF THE INVENTION A process for the preparation of vinyl acetate by catalytic synthesis from acetylene and acetic acid, wherein the unreacted raw materials are coated with the preparation of the reaction mixture and characterized in that. That is, fresh water acetic acid is metered into the recovered acetic acid phase, the weight ratio of which is 1 to 2%, and mixed with the recycled acetylene and the fresh ethylene is fed to the recycled acetylene or to the unit. of the synthesis mixture in the amount corresponding to the total loss of the amount of the reaction product formed and the technological losses, while maintaining the synthesis temperature of the synthesis mixture at at least 60 ° C, and the synthesis mixture thus prepared is separated into process streams and fed to pre-heated individual reaction systems.