GB750907A - Derivatives of 1, 3, 4-thiadiazole-2, 5-dithiol and the use of such derivatives as additives for hydrocarbon lubricants and as vulcanization accelerators - Google Patents

Abstract

The invention comprises thiadiazole derivatives of the formul <FORM:0750907/IV(a)/1> <FORM:0750907/IV(a)/2> and <FORM:0750907/IV(a)/3> where R1 is alkyl, aralkyl, cycloalkyl, alkylcycloalkyl, aryl or alkaryl, R2 is alkyl, aralkyl, cycloalkyl or alkylcycloalkyl (or R1 and R2 together form a polymethylene or oxapolymethylene group), Z and Za are hydrogen, alkali metal, ammonium or the group <FORM:0750907/IV(a)/4> and Zb is alkali metal or ammonium. These compounds are formed in admixture by reacting an alkali metal or ammonium salt of 1 : 3 : 4-thiadiazole-2 : 5-dithiol with a thiocarbamyl halide <FORM:0750907/IV(a)/5> where X is chlorine, bromine or iodine. The products comprising the various isomeric mono- and di-thiocarbamic esters are formed, depending on the proportion of the reactants, and can be separated by normal methods, e.g. fractional crystallization. The reaction is preferably carried out in water or an inert organic liquid at temperatures below 100 DEG C., e.g. 20-80 DEG C. It may be performed batch-wise, semicontinuously or continuously, at pressures at, below, or above atmospheric. The thiadiazole-2 : 5-dithiol may be made as in Specification 750,983 and the thiocarbamyl halide as in Specification 650,056, experimental details of these methods being given. Examples show the production of the following thiocarbamyl derivatives of 1 : 3 : 4-thiadiazole-2 : 5-dithiol : 2 : 5 - bis - derivatives: dimethyl, diethyl, diisopropyl, di-n-butyl, di-isobutyl, di-sec.-butyl, di - n - octyl, dicyclohexyl, butyl - cyclohexyl, ethyl-phenyl, dibenzyl, pentamethylene: 2-mono-derivative: diethyl; 3 : 4-bis-derivative: di-isopropyl. Many other suitable groups are mentioned, preference being given to C1-C8 alkyl.ALSO:<FORM:0750907/III/1> Thiadiazole derivatives of the formulae and <FORM:0750907/III/2> are added to lubricants such as hydrocarbon oils and greases to increase their stability against oxidation deterioration, sludge formation and the like, R1 is alkyl, aralkyl, cycloalkyl, alkyl-cycloalkyl, aryl or alkaryl, R2 is alkyl, aralkyl, cycloalkyl or alkylcycloalkyl (or R1 and R2 together form a polymethylene or oxapolymethylene group), Z and Za are hydrogen, alkali metal, ammonium or the group <FORM:0750907/III/3> and Zb is alkali metal or ammonium. In an example 1 : 3 : 4-thiadiazole-2 : 5-dithiol bis-(di-n-butyldithiocarbamate) is added to a mineral lubricating oil. Other suitable compounds are mentioned.ALSO:Thiadiazole derivatives of the formul : <FORM:0750907/V/1> and <FORM:0750907/V/2> are used as vulcanization accelerators for rubber; R1 is alkyl, aralkyl, cycloalkyl, alkylcycloalkyl, aryl or alkaryl, R2 is alkyl, aralkyl, cycloalkyl or alkylcycloalkyl (or R1 and R2 together form a polymethylene or oxapolymethylene group), Z and Za are hydrogen, alkali metal, ammonium or the group <FORM:0750907/V/3> and Zb is alkali metal or ammonium. In examples one each of the following compounds is blended with synthetic rubber, carbon black, zinc oxide, coal tar softener and sulphur, and the mixture heated under pressure:-1 : 3 : 4-thiadiazole-2 : 5 - dithiol bis dimethylthiocarbamic, diethyldithiocarbamic, di-isopropyldithiocarbamic, di-n-butyldithiocarbamic and pentamethylenedithiocarbamic esters, and 3 : 4 - bis - (di-isopropylthiocarbamyl) - 1 : 3 : 4 - thiadiazole - 2 : 5 - dithione. Other suitable compounds are mentioned.