Abstract: Thiocarbohydrazide (TCH) is made by reacting carbon disulfide and hydrazine in the presence of a mercaptan at an elevated temperature. The TCH is removed from the reaction mixture, the mother liquor is further treated to form HDTC which is further reacted to form TCH and the mother liquor is recycled. A major advantage of this process is the recyclability of the mother liquor without reduction in TCH yield.

Abstract: TCH is produced in two stages. In the first stage, carbon disulfide and excess hydrazine are reacted in the presence of a mercaptan and optionally a strong base or an amine other than hydrazine. Carbon disulfide and a strong base (if none was present during the first stage) are then added to the reaction mixture which is further reacted to complete the formation of TCH.

Abstract: In the production of an S-substituted isothiourea including the functional group ##STR1## in which R.sup.1 is an alkyl, alkenyl, aryl or aralkyl radical, wherein a thiourea including the functional group ##STR2## is reacted with an etherifying agent to replace H by R.sup.1, the improvement which comprises effecting the reaction in two steps, in the first step reacting the thiourea material with an etherifying agent including the radical Rin whichR is an alkyl, alkenyl aryl or aralkyl radical different from R.sup.1thereby to produce the ether ##STR3## and in the second step reacting the ether with a compound of the formula R.sup.1 SH. The process is particularly applicable to the production of the known herbicide ##STR4## from the corresponding thiourea where in the first step methyl bromide or methyl iodide is used to form the S-methyl isothiourea which is then interchanged with ethyl mercaptan. Higher overall yields and/or economies are thereby achieved.

Abstract: In the production of an S-substituted isothiourea including the function group ##STR1## in which R.sup.1 is an alkyl, alkenyl, aryl or aralkyl radical, wherein a thiourea including the functional group ##STR2## is reacted with an etherifying agent to replace H by R.sup.1, the improvement which comprises effecting the reaction in two steps, in the first step reacting the thiourea material with an etherifying agent including the radical Rin whichR is an alkyl, alkenyl aryl or aralkyl radical different from R.sup.1thereby to produce the ether ##STR3## and in the second step reacting the ether with a compound of the formula R.sup.1 SH. The process is particularly applicable to the production of the known herbicide ##STR4## from the corresponding thiourea where in the first step methyl bromide or methyl iodide is used to form the S-methyl isothiourea which is then interchanged with ethyl mercaptan. Higher overall yields and/or economies are thereby achieved.

Abstract: A process for the production of an S-substituted isothiourea including the functional group ##STR1## in which R.sup.1 is an alkyl, alkenyl, aryl or aralkyl radical, comprising reacting a thiourea including the functional group ##STR2## with an alpha-activated etherifying agent of the formulaX--A--Yin whichX is a halogen atom,A is a direct bond or CH.sub.2, andY is an electron withdrawing group, thereby to produce the ether ##STR3## and in a second step reacting the ether with a compound of the formula R.sup.1 SH. The process is particularly applicable to the production of the known herbicide ##STR4## from the corresponding thiourea where in the first step chloroacetic acid is used to form the S- carboxymethyl isothiourea which is then interchanged with ethyl mercaptan. Higher overall yields and/or economies are thereby achieved.