N,N-dimethylaminoethyl acrylate composition stabilized in respect of discoloring effects

Patent metadata

Field	Value
Publication number	US-10479757-B2
Application number	US-201716096305-A
Country	US
Kind code	B2
Filing date	Apr 24, 2017
Priority date	Apr 28, 2016
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

The invention relates to the use of 2,6,-di-tert-butyl-4-methylphenol at a moiety of 25 to 200 ppm for stabilizing N,N-dimethylaminoethyl acrylate in respect of discoloring effects. The invention also relates to an N,N-dimethylaminoethyl acrylate stabilized in said manner and to a method for producing the same.

First claim

The invention claimed is:

1. A process for the continuous production of a composition of N,N-dimethylaminoethyl acrylate that is stabilized with respect to coloration, comprising from 25 to 200 ppm of 2,6-di-tert-butyl-4-methylphenol, said process comprising the steps of transesterifying a light acrylate selected from the group consisting of methyl acrylate and ethyl acrylate, with dimethylaminoethanol in the presence of a catalyst, followed by a treatment for purifying a reaction mixture comprising a final distillation of purified N,N-dimethylaminoethyl acrylate, wherein 25 to 200 ppm of 2,6-di-tert-butyl-4-methylphenol are introduced at an outlet of the distilled gaseous stream of purified N,N-dimethylaminoethyl acrylate, before condensation of final product.

2. The process of claim 1 comprising the following steps:
a) transesterifying a light acrylate selected from the group consisting of methyl acrylate and ethyl acrylate, with dimethylaminoethanol in the presence of a transesterification catalyst and at least one polymerization inhibitor, a corresponding azeotropic mixture of light acrylate/light alcohol being drawn off continuously during the reaction;
b) conveying a crude reaction mixture to a first distillation column C1, referred to as tailing column, under reduced pressure, the crude reaction mixture comprising the desired N,N-dimethylaminoethyl acrylate with, as light products, dimethylaminoethanol and unreacted light acrylate and, as heavy products, the catalyst, the polymerization inhibitor(s) and heavy reaction by-products, to obtain:
at the top, a stream composed essentially of N,N-dimethylaminoethyl acrylate and light products, comprising a minor fraction of heavy products but devoid, or substantially devoid, of catalyst; and
at the bottom, a stream composed of heavy products with a minor fraction of N,N-dimethylaminoethyl acrylate and the catalyst; then

c) conveying the top stream from the first distillation column C1 to a second distillation column C2, referred to as topping column, under reduced pressure, to obtain:
at the top, a stream composed of light products with a minor fraction of N,N-dimethylaminoethyl acrylate; and
at the bottom, N,N-dimethylaminoethyl acrylate containing traces of light products, heavy reaction by-products and the polymerization inhibitor(s); then

d) conveying the bottom stream from the second distillation column C2 to a third distillation column C3, referred to as rectification column, under reduced pressure, into the top of which 25 to 200 ppm of 2,6-di-tert-butyl-4-methylphenol is introduced, to obtain:
at the top, a gaseous stream of purified N,N-dimethylaminoethyl acrylate that is stabilized with respect to coloration which is subsequently condensed; and
at the bottom, a stream consisting essentially of the polymerization inhibitor(s).

3. The process as claimed in claim 1 wherein the light acrylate is ethyl acrylate.

4. The process of claim 1 wherein the composition has a coloration of less than 100.

5. The process of claim 1 wherein the composition further comprises at least one polymerization inhibitor, selected from the group consisting of hydroquinone, hydroquinone methyl ether (MEHQ) and mixtures thereof.

Assignees

• Arkema France

Inventors

• Dubut Fanny
• Riflade Benoit
• Maget Sandra

Classifications

• C07C213/08

  by reactions not involving the formation of amino groups, hydroxy groups or etherified or esterified hydroxy groups · CPC title

• C07C213/10 Primary

  Separation; Purification; Stabilisation; Use of additives · CPC title

• C07C219/08

  having at least one of the hydroxy groups esterified by a carboxylic acid having the esterifying carboxyl group bound to an acyclic carbon atom of an acyclic unsaturated carbon skeleton · CPC title

• C08K5/08

  Quinones · CPC title

• C08K5/175

  containing COOH-groups; Esters or salts thereof · CPC title