g of 1 1 3 3 tetramethyl urea as the solvent in place of 1 methyl 1 pyrrolidone and additionally using 0 04 g of n n dimethyl aniline as the catalyst the results shown in table 1 and table 2 were obtained when the reaction was carried out by following the procedure of example 1 while using 13 8 g 0 1 mol of thiobenzoic acid as the thiol compound in place of methyl 3 mercapto propionate 13 8 g of n n dimethyl formamide as the solvent in place of 1 methyl 2 pyrrolidone 7 4 g 0 1 mol of propylene sulfide as the alkylene sulfide in place of ethylene sulfide and additionally using 0 14 g of n n dimethyl aniline as the catalyst the results shown in table 1 and table 2 were obtained table 1__________________________________________________________________________ alkylene molar ratio ofthiol compound sulfide raw materials amount of solvent addedexample a b a b solvent wt based on thiol__________________________________________________________________________ compound 1 methyl 3 mercapto propionate es 5 1 1 methyl 2 pyrrolidone 1002 methyl 3 mercapto propionate es 5 1 n n dimethyl formamide 503 methyl 3 mercapto propionate es 5 1 n n dimethyl acetamide 504 methyl 3 mercapto propionate es 5 1 1 3 dimethyl 2 imidazolidinone 1005 methyl 3 mercapto propionate es 5 1 n n dimethyl formamide 506 methyl 3 mercapto propionate es 5 1 n n dimethyl acetamide 507 methyl 3 mercapto propionate es 5 1 n n dimethyl formamide 508 methyl 3 mercapto propionate es 4 1 1 methyl 2 pyrrolidone 2009 n dodecyl 2 mercapto acetate es 2 1 1 3 dimethyl 2 imidazolidinone 10010 2 mercapto ethanol es 3.