Patent GB-392046-A (GB)
Title: The manufacture and application of new accelerators for vulcanisation
IPC: C08K5/00
Filed: 1932-09-16
Abstract: The sulphhydryl group of compounds containing the grouping:--<FORM:0392046/IV/1> or <FORM:0392046/IV/2> is etherified by an aryl radicle containing a nitro group and in m-position to the nitro group the group <FORM:0392046/IV/3> , wherein x indicates hydrogen, a substituted or unsubstituted alkyl, aryl, aralkyl, alkoxy or hydroaryl radicle, or a substituted or unsubstituted amino group. Thus a salt of the sulphhydryl compound may be reacted with an appropriate nitrohalogenaryl compound in an aqueous or organic medium while gently heating.  Suitable sulphhydryl compounds are mercaptoarylenethiazoles such as 2-mercaptobenzthiazole, 2-mercapto-1<1>.2<1>-naphthothiazole, which compounds may contain monovalent substituents such as chlorine or bromine, nitro, amino dimethylamino, alkyl (methyl, ethyl, butyl), aryl (phenyl) or alkoxy (methoxy, ethoxy) groups; or dithiocarbamates derived from secondary amines such as dimethylamine, diethylamine, methylethylamine, dibenzylamine, ethylcyclohexylamine, dicyclohexylamine, N-methylaniline, piperidine, morpholine, thiomorpholine and hexahydrocarbazole.  Suitable nitrohalogenaryl compounds are 3 - nitro - 4 - chlorbenzaldehyde, 3.3<1>-dinitro-4.4<1>-dichlorbenzophenone, 3 - nitro - 4 - chlor - benzoic acid methyl ester, 2-chloro-5-nitrobenzoic acid cyclohexyl ester, 2-chloro-5-nitrobenzoic acid piperidide, 2-chloro-5-nitrobenzoic acid butylamide (these latter three compounds are prepared by condensing 2-chloro-5-nitrobenzoyl chloride with cyclohexanol, piperidine and butylamine respectively), 2-chloro-5-nitroacetophenone, and 2-chloro-5-nitrodesoxybenzoin (prepared by condensing phenylacetyl chloride with p-nitrochlorbenzene in the presence of aluminium chloride).  The reaction products of 2-mercaptobenzthiazole with 3-nitro-4-chlorbenzaldehyde and 2-chloro-5-nitrobenzoic acid butylamide, of dimethyldithiocarbamic acid with 3-nitro-4-chlorobenzoic acid methyl ester, of pentamethylenedithiocarbamic acid with 3-nitro-4-chlorbenzoic acid methyl ester and 3-nitro-4-chlorbenzaldehyde, of ethylcyclohexyldithiocarbamic acid with 3-nitro-4-chlorbenzoic acid methyl ester, and of dicyclohexyldithiocarbamic acid with 3-nitro-4-chlorbenzoic acid methyl ester are specified in examples. Specifications 340,083, 340,574, 340,951, and 342,330 are also referred to.ALSO:Natural rubber and artificial rubber-like masses are vulcanized in the presence of accelerators containing the groupings: <FORM:0392046/V/1> or <FORM:0392046/V/2> wherein the NO2 group stands in o- or p-position to the sulphur atom, and in mposition to the carbon atom marked (1), and in which x indicates hydrogen, an alkyl, aryl, aralkyl, alkoxy, hydroaryl or amino group.  These accelerators are obtained by etherifying the sulphhydryl group of compounds containing the group <FORM:0392046/V/3> by an aryl radicle containing a nitro group and in mposition to the nitro group the group <FORM:0392046/V/4> wherein x indicates hydrogen, a substituted or unsubstituted alkyl, aryl, aralkyl, alkoxy or hydroaryl radicle, or a substituted or unsubstituted amino group.  Thus a salt of the sulphhydryl compound is reacted with an appropriate nitrohalogenaryl compound in an aqueous or organic medium with gentle heating. Suitable sulphhydryl compounds are mercaptoarylthiazoles such as 2-mercaptobenzthiazole, or 2-mercapto-11 : 21-naphthothiazole, which compounds may be substituted by monovalent substituents such as chlorine or bromine, nitro, amino, dimethylamino, alkyl (methyl, ethyl, butyl), aryl (phenyl), or alkoxy (methoxy, ethoxy) groups, or dithiocarbamates derived from secondary amines, such as dimethyl- and diethylamine, methylethylamine, dibenzylamine, ethylcyclohexylamine, dicyclohexylamine, N-methylaniline, piperidine, morpholine, thiomorpholine and hexahydrocarbazole. Suitable nitrohalogenaryl compounds are 3-nitro-4-chlorbenzaldehyde, 3 : 31 - dinitro - 4 : 41 - di-chlorobenzophenone, 3 - nitro - 4 - chlorobenzoic acid methyl ester, 2-chloro-5-nitrobenzoic acid cylohexyl ester, 2-chloro-5-nitrobenzoic acid piperidine, 2-chloro-5-nitrobenzoic acid butylamide (these three latter compounds are prepared by reacting 2-chloro-5-nitrobenzoyl chloride with cyclohexanol, piperidine and butylamine respectively), 2-chloro-5-nitroacetophenone and 2-chloro-5-nitrodesoxybenzoin (prepared by condensing phenylacetyl chloride with p-nitrochlorobenzene in the presence of aluminium chloride). These accelerators are in some cases preferably employed with other accelerators, and are incorporated into the rubber mixes together with any other desired ingredients, filling materials, pigments, softeners and antiperishing agents.  They possess a good critical temperature and compared with the products of Specifications 340,083, 340,574, 340,951 and 342,330, [all in Group IV], they are distinguished by being powerful accelerators causing no discolouration of the vulcanisates.  Examples are given showing the accelerating properties of some of the reaction products derived from the components listed above in a rubber-mix. Artificial rubber-like masses may be similarly vulcanized.