{HEAD ~ The present invention} ensures {TAIL ~ ready and efficient production} of 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 
ensures
{ HEAD ~ The present invention } ensures { TAIL ~ ready and efficient production } of 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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