Patent GB-760181-A (GB)
Title: Improvements in the production of substitution products of 1.3.4-thiadiazole
Filed: 1954-08-10
Abstract: Compounds of the general formula: <FORM:0760181/IV(a)/1> wherein X is a -CO-, -SO2-, or -CH2- group Y is a saturated aliphatic hydrocarbon radical containing from 5 to 18 carbon atoms and in which the free valency is satisfied by a hydrogen atom, a saturated aliphatic hydrocarbon radical, the group -CH2-COOH or -X-Y or another group <FORM:0760181/IV(a)/2> are used as plasticizers for polyvinyl chloride.  The use of 2,5-di-(2-ethyl-n-hexyl-mercapto)-1,3,4-thiadiazole is specifically mentioned.ALSO:The invention comprises substituted 2 : 5-dimercapto-1 : 3 : 4-thiadiazoles containing the structure -S-(C2N2S)-S-X-Y, wherein X is a -CO-, -SO2- or -CH2- group, Y is a saturated aliphatic hydrocarbon radical containing from 5 to 18 carbon atoms, and in which the free valency is satisfied by a hydrogen atom, a saturated aliphatic hydrocarbon radical, the group -CH2COOH or -X-Y or another group -S-(C2N2S)-S-X-Y.  The invention also comprises a process for the production of the compounds H-S-(C2N2S)-S-X-Y and Y-X-S-(C2N2S)-S-X-Y by reacting 2 : 5 - dimercapto - 1 : 3 : 4 - thiadiazole with either one or two molecular proportions of a compound Hal-X-Y, followed, if desired, by conversion of H-S-(C2N2S)-S-X-Y into a disulphide or by reaction of this compound with a compound Hal-CH2.COOH.  The first reaction is carried out in weakly acid or, preferably, alkaline solution in the presence of diluents such as water, alcohols or mixtures thereof, alkaline solutions being prepared by the addition of caustic alkali, alkali metal carbonates, alcoholates or tertiary amines.  Suitable reaction temperatures are in the range of - 10 DEG  to 200 DEG  C.  The oxidation to disulphides may be effected with, for example, alcoholic iodine, hydrogen peroxide, bleaching powder or chlorine.  In the examples, 1 mol. of 2 : 5-dimercapto - 1 : 3 : 4 - thiadiazole is reacted with 2 mols. of n-octyl chloride, 2-ethyl-n-hexyl bromide and dodecyl bromide to give respectively 2 : 5 - di - (n - octylmercapto) -, 2 : 5 - di - (2 - ethyl - n - hexylmercapto) - and 2 : 5 - di - (dodecylmercapto) - 1 : 3 : 4 - thiadiazole; 1 mol. of 2 : 5 - dimercapto - 1 : 3 : 4 - thiadiazole gives, with 1 mol. of n-octyl bromide or iodide, 2-(n-octylmercapto)-5-mercapto-1 : 3 : 4-thiadiazole which is then oxidized to 2 : 21-dithio-bis-(5-n-octylmercapto - 1 : 3 : 4 - thiadiazole); 2 - (2 - ethyl - n - hexylmercapto) -, 2 - dodecylmercapto - and 2 - octadecylmercapto - 5 - mercapto - 1 : 3 : 4 - thiadiazole and the corresponding disulphides are similarly prepared, and the cyclohexylamine salt of the first is also prepared; 2 : 5-dimercapto-1 : 3 : 4-thiadiazole is reacted with either one or two molecular proportions of 2-ethylhexanoyl chloride to give the appropriate mono- or di-substituted 1 : 3 : 4-thiadiazoles, and with 1 mol. of decyl sulphochloride to give 5-decylsulphonylmercapto-2-mercapto - 1 : 3 : 4 - thiadiazole; and 2 - (2 - ethyl - n - hexylmercapto) - 5 - mercapto - 1 : 3 : 4 - thiadiazole and monochloracetic acid react to give 2-(2-ethyl-n-hexylmercapto)-5 carboxymethylmercapto - 1 : 3 : 4 - thiadiazole.  Other starting materials referred to include sperm oil chloride, sperm oil fatty acid chloride, 2-ethylheptanoyl chloride, decyl and undecyl sulphonic acid chloride and palmitic acid chloride or bromide.  Starting material.  2,5-Dimercapto-1,3,4-thiadiazole is prepared from hydrazine in aqueous solution containing free alkali by treatment with carbon disulphide and acidification.ALSO:Compounds of the general formula:-  <FORM:0760181/II/1> wherein X is a - CO -, - SO2 -, or - CH2 - group, Y is a saturated aliphatic hydrocarbon radical containing from 5 to 18 carbon atoms and in which the free valency is satisfied by a hydrogen atom, a saturated aliphatic hydrocarbon radical, the group - CH2 - COOH or - X - Y or another group Y - X - S - (C2N2S) - S - are added to alkaline cleaning agents containing phosphates to prevent the corrosion or tarnishing of metals.ALSO:Compounds of the general formula <FORM:0760181/V/1> where X is a -CO-, -SO2-, or -CH2- group, Y is a saturated aliphatic hydrocarbon radical containing from 5 to 18 carbon atoms and in which the free valency is satisfied by a hydrogen atom, a saturated aliphatic hydrocarbon radical, the group -CH2-, COOH or -X-Y or another group Y-X-S- (C2N2S)-S- are used as vulcanization accelerators.  Examples are given specifying, as vulcanization accelerators of the above formula, 2, 21 dithio-bis (5n -octylmercapto-1, 3, 4 thiadiazole) and the cyclohexylamine salt of 2- (2-ethyl-n-hexthylmercapto)-5-mercapto-1, 3, 4-thiadiozole.ALSO:Compounds of the general formula <FORM:0760181/VI/1> wherein X is a -CO-, -SO2-, or -CH2- group, Y is a saturated aliphatic hydrocarbon radical containing from 5 to 18 carbon atoms and in which the free valency is satisfied by a hydrogen atom, a saturated aliphatic hydrocarbon radical, the group -CH2-COOH or -X-Y or another group Y-X-S-(C2N2S)-S- are used as light protective agents. The following compositions are referred to: 2.5-di-(n-octylmercapto)-1.3.4-thiadiazole as an alcoholic solution, an aqueous emulsion and a cream; 2.21-dithio - bis - (5 - n - octyl - mercapto-1.3.4-thiadiazole) as an alcoholic solution; and 2-(2-ethyl-n-hexylmercapto) -5-carboxymethyl-mercapto-1.3.4-thiadiazole as an aqueous emulsion. The use of 2.5-di-(dodecylmercapto)-1.3.4-thiadiazole and 2.21 - dithio - bis - (5 - (2 - ethyl - n-hexylmercapto)-1.3.4-thiadiazole) as sunburn preparations is also referred to.