{TAIL ~ The present invention} ensures ready and efficient production of {HEAD ~ a polar vinyl compound} such as N vinylcarboxamide which is highly purified and thus has high polymerizability from a crude polar vinyl compound containing impurities such as polymerization inhibiting substances and starting materials used in synthesis of the polar vinyl compound 
{ TAIL ~ The present invention } ensures ready and efficient production of { HEAD ~ a polar vinyl compound } such as N vinylcarboxamide which is highly purified and thus has high polymerizability from a crude polar vinyl compound containing impurities such as polymerization inhibiting substances and starting materials used in synthesis of the polar vinyl compound
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