Method for preparing an aqueous acrylamide solution having a low acrylic acid concentration
First Claim
1. A method for preparing an aqueous acrylamide solution, the method comprising:
- (a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion;
(b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor; and
(c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor, for 10 minutes to 48 hours,wherein the adding of further acrylonitrile comprises;
(i) maintaining an acrylonitrile content in a first range, which is from 1.2 w/w % to 6 w/w % relative to the total weight of the composition in the reactor, for a first period of time, which is from 30 minutes to 4 hours;
(ii) decreasing the acrylonitrile content from the first range to a second range, which is from 0.3 w/w % to 1.2 w/w % relative to the total weight of the composition in the reactor; and
(iii) maintaining an acrylonitrile content in the second range for a second period of time, which is from 30 minutes to 24 hours.
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Abstract
The present invention relates to methods for preparing an aqueous acrylamide solution having a low acrylic acid concentration. In addition, the present invention relates to methods for reducing the acrylic acid concentration of an aqueous acrylamide solution. The methods involve a bioconversion of acrylonitrile to acrylamide in the presence of a biocatalyst, wherein during the bioconversion the content of acrylonitrile is maintained at 0.3 w/w % or more referred to the total weight of the composition in the reactor. Also provided is an aqueous acrylamide solution which is obtained by the methods of the present invention. Furthermore, the present invention is related to an acrylamide homopolymer or copolymer obtained by polymerizing the acrylamide of the aqueous solution.
13 Citations
29 Claims
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1. A method for preparing an aqueous acrylamide solution, the method comprising:
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(a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion; (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor; and (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor, for 10 minutes to 48 hours, wherein the adding of further acrylonitrile comprises; (i) maintaining an acrylonitrile content in a first range, which is from 1.2 w/w % to 6 w/w % relative to the total weight of the composition in the reactor, for a first period of time, which is from 30 minutes to 4 hours; (ii) decreasing the acrylonitrile content from the first range to a second range, which is from 0.3 w/w % to 1.2 w/w % relative to the total weight of the composition in the reactor; and (iii) maintaining an acrylonitrile content in the second range for a second period of time, which is from 30 minutes to 24 hours. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for preparing an aqueous acrylamide solution, the method comprising:
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(a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion; (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor; and (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more until an acrylamide content reaches at least 20 w/w %, relative to the total weight of the composition in the reactor, wherein the adding of further acrylonitrile comprises; (i) maintaining an acrylonitrile content in a first range, which is from 1.2 w/w % to 6 w/w % relative to the total weight of the composition in the reactor, for a first period of time, which is from 30 minutes to 4 hours; (ii) decreasing the acrylonitrile content from the first range to a second range, which is from 0.3 w/w % to 1.2 w/w % relative to the total weight of the composition in the reactor; and (iii) maintaining an acrylonitrile content in the second range for a second period of time, which is from 30 minutes to 24 hours. - View Dependent Claims (22, 23)
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24. A method for reducing an acrylic acid concentration of an aqueous acrylamide solution prepared by converting acrylonitrile to acrylamide using a biocatalyst, the method comprising:
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(a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion; (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor; and (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor, wherein the adding of further acrylonitrile comprises; (i) maintaining an acrylonitrile content in a first range, which is from 1.2 w/w % to 6 w/w % relative to the total weight of the composition in the reactor, for a first period of time, which is from 30 minutes to 4 hours; (ii) decreasing the acrylonitrile content from the first range to a second range, which is from 0.3 w/w % to 1.2 w/w % relative to the total weight of the composition in the reactor; and (iii) maintaining an acrylonitrile content in the second range for a second period of time, which is from 30 minutes to 24 hours. - View Dependent Claims (25, 26)
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27. A method for preparing an aqueous acrylamide solution, comprising:
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(a) adding acrylonitrile, water, and a biocatalyst capable of converting acrylonitrile to acrylamide to a reactor to obtain a composition for bioconversion; (b) performing a bioconversion of the acrylonitrile to acrylamide in the reactor; (c) adding further acrylonitrile such that a content of acrylonitrile during the bioconversion is maintained at 0.3 w/w % or more, relative to the total weight of the composition in the reactor; and (d) obtaining a composition at the end of the bioconversion, which has an acrylic acid concentration of 1500 ppm or less, relative to the total weight of the composition at the end of the bioconversion, wherein the adding of further acrylonitrile comprises; (i) maintaining an acrylonitrile content in a first range, which is from 1.2 w/w % to 6 w/w % relative to the total weight of the composition in the reactor, for a first period of time, which is from 30 minutes to 4 hours; (ii) decreasing the acrylonitrile content from the first range to a second range, which is from 0.3 w/w % to 1.2 w/w % relative to the total weight of the composition in the reactor; and (iii) maintaining an acrylonitrile content in the second range for a second period of time, which is from 30 minutes to 24 hours. - View Dependent Claims (28, 29)
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Specification