Process for producing 1, 3-dialkyl-2-imidazolidinone

In the production process of a 1,3-dialkyl-2-imidazolidinone expressed by the formula (2) ##STR11## wherein R represents --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 or --C.sub.4 H.sub.9, by reacting a N,N'-dialkylethylenediamine expressed by the formula (1) ##STR12## wherein R is as defined above, with urea, the improvement which comprises reacting said N,N'-dialkylethylenediamine with urea in a quantity of twice or less by mol the quantity of said N,N'-dialkylethylenediamine in the presence of a non-protonic polar solvent at a temperature of 140.degree. C. or lower until formation of a 1,1'-dialkyl-1,1'-dimethylenebisurea as an initial period reaction product is completed, and successively raising the temperature up to a temperature of 180.degree. C. or higher at which the latter period reaction is then carried out under pressure.

In the production process of a 1,3-dialkyl-2-imidazolidinone expressed by the formula (2) ##STR13## wherein R represents --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7 or --C.sub.4 H.sub.9, by reacting a N,N'-dialkylethylenediamine expressed by the formula (1) ##STR14## wherein R is as defined above with urea, the improvement which comprises reacting said N,N'-dialkylethylenediamine with urea in a quantity of about twice by mol the quantity of said N,N'-dialkylethylenediamine in the presence of a non-protonic polar solvent at a temperature of 140.degree. C. or lower until formation of a 1,1'-dialkyl-1,1'-dimethylenebisurea as an initial period reaction product is completed, and successively carrying out a latter period reaction at a temperature of 180.degree. C. or higher while additionally adding said N,N'-dialkylethylenediamine.