Unlock instant, AI-driven research and patent intelligence for your innovation.

Process for the production of vinyl acetate by inhibiting by-product formation

A technology of vinyl acetate and products, which is applied in the field of preparing vinyl acetate, and can solve the problems of insufficient effect of N-oxyl compounds and insufficient storage stability

Active Publication Date: 2017-08-25
WACKER CHEM GMBH
View PDF10 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In fact, the assumption so far is that without drying and purification, the effect and storage stability of N-oxyl compounds are insufficient

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Process for the production of vinyl acetate by inhibiting by-product formation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] After the completion of Comparative Example 1, a total of 50 to 200 ppm of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy (4-OH-TEMPO) per metric ton of VAM, in all cases The aqueous solution as a 75% concentration by weight is added at points A to L in a period of another month.

[0052] After the end of the month of inhibition with the aqueous OH-TEMPO solution, the following polymer formation rates were measured in the tower:

[0053] Dehydration tower K-301(11): 10-20kg / h

[0054] Pure VAM Tower K-302(16): 1-3kg / h

[0055] Azeotropic tower K-304(9): 8-10kg / h

Embodiment 2

[0057] After Example 1 has been terminated, a total of 50 to 200 ppm of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) per metric ton of VAM is used as a 75% concentration by weight in all cases The aqueous solution of is added at points A to L during another month.

[0058] After the end of the month of inhibition with the aqueous TEMPO solution, the following polymer formation rates were measured in the tower:

[0059] Dehydration tower K-301(11): 11-22kg / h

[0060] Pure VAM Tower K-302(16): 2-4kg / h

[0061] Azeotropic tower K-304(9): 10-12kg / h

[0062] Although the amount of TEMPO and 4-OH-TEMPO used is significantly smaller, and although they are used in the form of a highly concentrated aqueous solution, a significantly more effective polymer formation is achieved compared to hydroquinone inhibition for one month Suppression.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention relates to a process for the production of vinyl acetate by reaction of ethylene with acetic acid and oxygen in a continuous gas phase process utilizing heterogeneous catalysis and subsequent treatment of the product gas stream by adding one or more compounds containing at least An N-oxyl compound of N-oxyl radical-N-O" as an inhibitor to inhibit the polymerization of vinyl acetate during the processing of the product gas mixture, characterized in that the N-oxyl compound is present in an amount of 50 to Added as an 85% strength aqueous solution.

Description

Technical field [0001] The present invention relates to a method for preparing vinyl acetate in a heterogeneously catalyzed continuous gas-phase process by reacting ethylene with acetic acid and oxygen and processing a product gas stream, wherein the process of processing the product gas stream is suppressed due to vinyl acetate A by-product of ester polymerization is formed. Background technique [0002] Vinyl acetate monomer (VAM) can be produced in a continuous process with recirculation of the purified product stream (cycle gas process). This involves the reaction of ethylene with acetic acid and oxygen in a heterogeneous catalyzed gas phase process on a catalyst which generally contains palladium and alkali metal salts on a support material and may be additionally doped with gold, rhodium or cadmium. Preference is given to the use of a Pd / Au catalyst mixture and potassium acetate promoter. [0003] The reactants of ethylene, oxygen and acetic acid react exothermically (VAM: ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/05
CPCC07C67/05C07C67/62C07C69/15C07C67/04
Inventor 维利巴尔德·达芬格马克·埃克特
Owner WACKER CHEM GMBH