CPC C07C 231/24 (2013.01) [C07C 233/05 (2013.01)] | 7 Claims |
1. A method for producing a highly polymerizable N-vinyl carboxylic acid amide monomer, comprising
(A) a step of melting a crude N-vinyl carboxylic acid amide monomer comprising 50 to 88 mass % of an N-vinyl carboxylic acid amide monomer by heating, followed by cooling for precipitation, and subjecting precipitated N-vinyl carboxylic acid amide monomer crystals to solid-liquid separation, and
(B) a step of further dissolving the N-vinyl carboxylic acid amide monomer crystals separated in the step (A) in a mixed solvent of acetonitrile and an aliphatic hydrocarbon having 6 to 7 carbon atoms, then performing crystallization, performing solid-liquid separation, and recovering an N-vinyl carboxylic acid amide monomer purified product, wherein
a mass ratio of acetonitrile/N-vinyl carboxylic acid amide monomer crystal in the step (B) is 0.01:1.0 or more and 0.5:1.0 or less, and
a mass ratio of aliphatic hydrocarbon having 6 to 7 carbon atoms/N-vinyl carboxylic acid amide monomer crystal in the step (B) is 0.5:1.0 or more and 3.0:1.0 or less.
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