Patent GB-745222-A (GB)
Title: Substituted dithiocarbamates and their use as vulcanization accelerators
IPC: C08K5/00
Filed: 1953-03-25
Abstract: Synthetic rubber, e.g. a butadiene-styrene copolymer, is vulcanized using as a vulcanization accelerator a thiadiazoline of the general formula <FORM:0745222/IV(a)/1> wherein Ar represents an unsubstituted aryl radical or a substituted aryl radical which has not more than 3 halogen or alkyl substituents, R1 represents an alkyl, aralkyl, aryl, alkaryl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical, or is joined to R2 so that R1 and R2 together represent a polymethylene or oxapolymethylene radical, and R2, when not joined to R1, represents an alkyl, aralkyl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical which may or may not be the same as R1.  In an example a composition containing a butadienestyrene copolymer, carbon black, zinc oxide, a high boiling coal-tar oil and sulphur is vulcanized using 3-phenyl-2-thiono-1,3,4-thiadiazolinyl - 5 - diethyldithiocarbamate as the vulcanization accelerator. Specification 650,056, [Group IV (b)], is referred to.ALSO:The invention comprises thiadiazolines of the general formula <FORM:0745222/IV(a)/1> wherein Ar represents an unsubstituted aryl radical or a substituted aryl radical containing not more than 3 halogen or alkyl substituents, R1 represents an alkyl, aralkyl, aryl, alkaryl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical, or is joined to R2 so that R1 and R2 together represent a polymethylene or oxapolymethylene radical, and R2, when not joined to R1, represents an alkyl, aralkyl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical which may or may not be the same as R1, and the preparation thereof by reacting a compound of the general formula <FORM:0745222/IV(a)/2> wherein M represents an alkali metal or the ammonium radical and Ar has the above significance, with a compound of the general formula <FORM:0745222/IV(a)/3> wherein R1 and R2 have the above significance and X represents a halogen. Preferably X represents chlorine, bromine or iodine, and M represents sodium or potassium.  The reaction may be carried out at a temperature below 100 DEG  C., a preferred reaction temperature being between 20 DEG  and 80 DEG  C.  Suitable reaction solvents are aliphatic and aromatic hydrocarbons such as hexane, petroleum naphtha, benzene and toluene, chlorinated hydrocarbons such as carbon tetrachloride and chlorobenzene, and water.  N-substituted thiocarbamyl halides which may be used in the above process include those in which R1 ane R2 both represent the same radical, e.g. diethyl- and bis-(2-methylcyclohexyl)-thiocarbamyl chlorides, or different radicals of the same generic type, e.g. methylamyl-, benzyl-phenylethyl- and cyclobutylcyclopentyl-thiocarbamyl chlorides, or two different radicals, e.g. naphthyl-3-ethylcyclohexyl-, methyl-benzyl- and furfuryl-propylthiocarbamyl chlorides, or those in which R1 and R2 together represent one radical, e.g. the tetra- and penta-methylene and 3-oxapenta-methylene radicals.  The alkyl radicals may contain 1 to 18 carbon atoms, e.g. 1 to 8 carbon atoms-particularly not more than 6 carbon atoms.  Suitable aralkyl radicals are benzyl, phenylethyl and phenylpropyl radicals, suitable aryl radicals are phenyl, a - and b -naphthyl and o-tolyl radicals, suitable alkaryl radicals are 2,4,6-trimethylphenyl, 2-methyl-5-butylphenyl and b -(6-methylnaphthyl) radicals, suitable substituted aryl radicals are p-chlorophenyl, 2-methyl-4-bromophenyl and 3,4,5-triiodophenyl radicals, and suitable cycloalkyl and alkyl-substituted cycloalkyl radicals are cyclopropyl, decahydronaphthyl, 3,4-dimethylcyclohexyl and 3 - amylcyclohexyl radicals.  When the aryl radical Ar contains alkyl substituents, each alkyl substituent may contain not more than 5 carbon atoms-preferably so that the total number of carbon atoms in any such substituted aryl radical does not exceed 16.  In the examples, 3-p-bromophenyl-, 3-p-chlorophenyl-, 3-a -naphthyl- and 3-phenyl-2-thiono - 1,3,4 - thiadiazolinyl - 5 - diethyldithio-carbamates are prepared.  Other compounds which are obtainable are 3-(2,4-diiodophenyl) - 2 - thiono - 1,3,4 - thiadiazolinyl - 5 - bis - (2 - methylcyclohexyl) - dithiocarbamate, 3 - (b  - naphthyl) - 2 - thiono - 1,3,4-thiadiazolinyl - 5 - ethyl - o - tolyl - dithiocarbamate, 3 - (b  - 6 - methylnaphthyl) - 2- thiono - 1,3,4 - thiadiazolinyl - 5 - dimethyldithiocarbamate, 3 - phenyl - 2 - thiono - 1,3,4-thiadiazolinyl - 5 - benzyl - phenylethyl - dithiocarbamate, 3 - (2,4,6 - trichlorophenyl)-2 - thiono - 1,3,4 - thiadiazolinyl - 5 - diethyldithiocarbamate, 3 - (2,5,6 - triethylphenyl)-2 - thiono - 1,3,4 - thiadiazolinyl - 5 - diethyldithiocarbamate, 3 - phenyl - 2 - thiono - 1,3,4-thiazdiazolinyl - 5 - hexamethylenedithiocarbamate, 3 - phenyl - 2 - thiono - 1,3,4 - thiadiazolinyl - 5 - oxapentamethylene - dithiocarbamate, 3 - - chlorophenyl - 2 - thiono-1,3,4 - thiadiazolinyl - 5 - difurfuryl - dithiocarbamate, 3 - a  - naphthyl - 2 - thiono - 1,3,4- thiadiazolinyl - 5 - methyltetrahydrofurfuryldithiocarbamate, 3 - a  - naphthyl - 2 - thiono-1,3,4 8 thiadiazolinyl - 5 - dimethyl - dithiocarbamate, 3 - phenyl - 2 - thiono - 1,3,4 - thiadiazolinyl - 5 - diamyl - dithiocarbamate, 3 - p-chlorophenyl - 2 - thiono - 1,3,4 - thiadiazolinyl- 5 - pentamethylene - diethiocarbamate and 3 - p - bromophenyl - 2 - thiono - 1,3,4 - thiadiazolinyl-5-diisopropyl-dithiocarbamate.  Sodium mercaptide of 3-p-bromophenyl-5-mercapto-1,3,4-thiadiazole-2(3)-thione is prepared by reacting p-bromophenylhydrazine hydrochloride, sodium hydroxide and carbon disulphide.  By a similar procedure the sodium mercaptide of 3-phenyl-(and 3-a -naphtyl-)-5-mercapto-1,3,4-thiadiazole-2(3)-thione and other 1,3,4 - thiadiazole - 2(3) - thiones of the general formula <FORM:0745222/IV(a)/4> wherein M and Ar have the above significance, may be prepared. Specification 650,056 is referred to.ALSO:Natural rubber is vulcanized using as a vulcanization accelerator a thiadiazoline of the general formula <FORM:0745222/V/1> wherein Ar represents an unsubstituted aryl radical or a substituted aryl radical which has not more than 3 halogen or alkyl substituents, R1 represents an alkyl, aralkyl, aryl, alkaryl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical or is joined to R2 so that R1 and R2 together represent a polymethylene or oxapolymethylene radical, and R2, when not joined to R1, represents an alkyl, aralkyl, cycloalkyl, alkyl-substituted cycloalkyl, furfuryl or tetrahydrofurfuryl radical which may or may not be the same as R1. Specification 650,056 is referred to.