Patent GB-489202-A (GB)
Title: Improvements in and relating to accelerators
IPC: C08K5/48
Filed: 1937-06-29
Abstract: The vulcanization of rubber is accelerated by the addition to the mix of a selenazyl-2-selenide compound.  These compounds are characterized by the presence of the grouping <FORM:0489202/IV/1> Attached to the open bonds of the adjacent carbon atoms of the selenazole ring, may be hydrogen, or aliphatic or aromatic radicals. The preferred embodiment is the inclusion of these two carbon atoms as part of an arylene radical such as phenylene, nitro phenylene or naphthylene radicals.  Attached to the open bond of the selenyl selenium atom may be hydrogen or any organic or inorganic radical such as salt or ester forming radicals.  The compounds are such that by hydrolysis, double decomposition, rearrangement of the atoms in the molecule, or by the application of heat they form the free selenyl compound or its diselenide. Compounds within the scope of the invention are the 2-selenyl selenazoles such as 2-selenyl benzoselenazole, the diselenazyl selenides such as di(benzoselenazyl) diselenide and di(benzoselenazyl) mono selenide; the metal salts of the 2-selenyl selenazoles, such as the zinc, lead, cadmium, mercury, calcium, sodium, potassium and barium salts of 2-selenyl benzoselenazole; the reaction products of alkali metal salts of the 2-selenyl selenazoles with chlorinated organic compounds such as the reaction products of sodium benzoselenazyl 2-selenide with the ortho nitro chlor benzenes and orthonitro phenyl sulphur halides such as 2-benzoyl-ortho nitro phenyl sulphur bromide and 2-nitro phenyl sulphur chloride; with the aromatic acyl halides such as benzoyl chloride and phthaloyl chloride; with the furoyl and tetrahydrofuroyl halides; with chlorinated ketones such as mono- and dichlor acetone and acetophenone; with the mono and dichlor acetates; with the mono and dichlor acetamides; with chlor benzothiazole, and with benzal chloride.  Also the reaction products of 2-selenyl benzoselenazole with formaldehyde, with amines such as o- and p-toluidine, o- and p-phenetidines, anisidine and alpha- and betanaphthylamines, with the guanidines such as diphenylguanidine and di-ortho-tolyl guanidine, with aldehyde amines such as ethylideneaniline, crotonylidene-aniline and hexamethylenetetramine.  Nitroso derivatives may be made by the action of gaseous ethyl nitrite on aryl amino methylene benzoselenenazyl - 2-selenides.  Other compounds are the reaction products of sodium selenazyl-2-selenides particularly sodium benzo-selenazyl-2-selenide with aryl seleno halides such as o-nitro phenyl seleno chloride and phenyl seleno chloride; with quinoline; with the reaction product of benzal chloride and hexamethylenetetramine, with carbonyl chloride to give dibenzoselenazyl diseleno carbonate, with thiophosgene to give a corresponding product; with quaternary ammonium halides such as hexadecyl pyridinium chloride, hexadecyl trimethyl ammonium bromide, benzyl trimethyl ammonium chloride, benzyl pyridine ammonium chloride, betahydroxy ethyl pyridine chloride, N-chloro piperidine, N-chloro-morpholine, dimethyl chlor amine, dibutyl chlor amine, diphenyl carbamine chloride, imino methylene dichlorides, and dichlor-di-imides.  Still other compounds are the reaction products of sodium 5-nitro-benzoselenazyl-2-selenide with 2-chlor quinoline, benzoselenazyl-2-seleno methylene hydrin with acetyl chloride, and 2-selenyl selenazoles such as benzoselenazole-2-seleno methylene hydrin with formaldehyde.  The addition products of amines and zinc selenazyl-2-selenides are also included and may be formed by adding the amine to the zinc salt in petroleum ether.  Amines mentioned are piperidine, cyclo-hexylamine, benzylamine, diamylamine, di-n-butylamine, di-isopropylamine, hexahydro phenetidine, hexahydro toluidine, ethylene diamine, tetrahydro alpha furfurylamine, N-methylcyclohexylamine, amyl amine, butyl amine, heptyl amine, and hexyl amine.  Another class of materials is that produced by the reaction of 2-selenyl selenazoles particularly 2-selenyl benzoselenazole with formaldehyde derivatives.  Compounds of this type which are mentioned are the reaction product of 2-selenyl benzoselenazole and methylol guanidines such as the reaction product of diphenylguanidine and formaldehyde, and the methylol amides such as the reaction product of acetamide or benzamide and formaldehyde. In all the above classes of compounds in which 2-selenyl benzoselenazole have been used, this may be replaced by other selenyl selenazoles.  Compounds mentioned are 2-selenyl selenazole, 5-nitro-6-chlor 2-selenyl selenazole, 4-phenyl-2-selenyl selenazole, 4 : 5-di-p anisyl-2 selenyl selenazole, 4 : 5-diphenyl-2-selenyl selenazole, 2-selenyl-5-nitro-benzoselenazole, 5-, 6- or 7-methyl-2-selenyl benzoselenazoles, 2 - selenyl - 4 : 6-dimethyl-benzoselenazole, 5-, 6- or 7-methoxy-2 - selenyl - benzoselenazoles, 2 - selenyl 5- or 6-chlor benzoselenazole, 5-, 6- or 7-hydroxy-2-selenyl benzoselenazoles, 2-selenyl-5- or 6-amino benzoselenazole, 2 - selenyl - AR - tetrahydroalpha-naphthoselenazole, 2-selenyl alpha or beta-naphthoselenazole, and 2-selenyl-6-phenylamino benzoselenazole. The preferred members of this series of compounds are the 2-selenyl arylene selenazoles of the benzene and naphthalene series.  The compounds of the invention may, with the exception of the 2-selenyl selenazoles, be prepared by reacting the 2-selenyl selenazole or a soluble salt thereof with the appropriate component, the processes being similar to those involved in preparing the corresponding derivatives of the 2-mercaptothiazoles.  In examples: (1) 2-selenyl benzoselenazole is prepared by the action of sodium selenide or hydroselenide on 2-chlor benzoselenazole.  By using the corresponding 2-chlor selenazole there may similarly be obtained 6 - nitro - 2 - selenyl benzoselenazole, 2-selenyl selenazole and 2 - selenyl alpha naphthoselenazole; (2) di-(benzoselenazyl) diselenide <FORM:0489202/IV/2> is prepared by subjecting 2-selenyl benzoselenazole in alcoholic solution to the action of oxidizing agents such as iodine, hydrogen peroxide and ammonium persulphate. Other diselenazyl diselenides which are mentioned as being prepared in a similar manner are di(6-nitro - benzoselenazyl) diselenide, diselenazyl diselenide, di(4 - methyl benzoselenazyl) diselenide, di(7-phenyl benzoselenazyl) diselenide, di(beta naphthoselenazyl) diselenide and di(5-ethoxy benzoselenazyl) diselenide; (3) metal salts of the 2-selenyl selenazoles other than the alkali metal salts are prepared by adding a solution of a soluble salt of the desired metal to an aqueous solution of an alkali salt of the 2-selenyl selenazole.  The preparation of the zinc salt is described in detail and other salts mentioned which may be similarly prepared are mercuric, cadmium, calcium and lead benzoselenazyl 2 - selenide, zinc 4 - methoxy benzoselenazyl-2-selenide, lead 7-ethyl benzoselenazyl 2-selenide, barium 5-ethoxy benzoselenazyl 2-selenide and zinc beta naphthoselenazole 2-selenide; (4) the piperidine salt of 2-selenyl benzoselenazole <FORM:0489202/IV/3> is prepared by suspending 2-selenyl benzoselenazole in ether and adding an equivalent amount of piperidine; (5) the cyclohexylamine salt of 2-selenyl benzoselenazole is prepared from cyclohexylamine in a similar manner to that used in example (5).  Other amine salts which are mentioned as being similarly prepared are the salts of either 2-selenyl benzoselenazole, 2-selenyl 6-ethoxy benzoselenazole, or 2-selenyl 4-phenyl benzoselenazole with the following amines: ethylene diamine, diethyl amine, butyl amine, dibutyl amine, tetrahydro alpha furfuryl amine, diamyl amine, N-ethyl cyclohexylamine, p-phenylene diamine, dibutyl ethylene diamine, di-isopropyl amine, and hexahydro phenetidine.  The guanidine salts are similarly prepared, examples being the salts of either 2-selenyl benzoselenazole, 2-selenyl-6-nitro benzoselenazole or 2-selenyl beta naphthselenazole with diphenyl-guanidine, mono phenyl guanidine, di-o-tolylguanidine, dixylyl guanidine, and triphenyl guanidine.  The ammonia reaction products may also be used, of which ammonium benzoselenazyl 2-selenide, and ammonium-4-phenyl-benzoselenazyl-2-selenide are examples.  The ammonia, guanidine, and amine reaction products of 2-selenyl selenazoles may be further reacted with aldehydes to form compositions of unknown constitution, which are, however, excellent accelerators.  Examples are the crotonaldehyde reaction product of the reaction product of 2-selenyl benzoselenazole and hexamethylenetetramine, the acetaldehyde reaction product of butyl ammonium benzoselenazyl 2-selenide, and the formaldehyde reaction product of the ethylene diamine addition product of 2-selenyl benzoselenazole; (6) the reaction product (constitution unknown) of 2-selenyl benzoselenazole formaldehyde and urea.  In this example, there may be used as alternatives the 6-methyl-, and the 6-hydroxy benzoselenazole, and also thio-urea; (7) 2 : 4-dinitrophenyl benzoselenazyl 2-selenide <FORM:0489202/IV/4> is prepared by refluxing in alcoholic solution molecular quantities of 2 : 4-dinitro chlor benzene and sodium benzoselenazyl-2-selenide.  Other similar compounds which are mentioned as being prepared in a similar manner are 2 : 6-dinitro-4 chlorphenyl-benzoselenazyl-2 selenide, 2 : 4 : 6-trinitro-phenyl benzoselenazyl 2-selenide and 2-nitrophenyl-benzoselenazyl 2-selenide; (8) benzothiazyl benzoselenazyl mono selenide <FORM:0489202/IV/5> is prepared by refluxing in benzene solution, molecular proportions of 2-selenyl benzoselanazole and 2-chlor-benzothiazole.  Another selenazyl thiazyl mono selenide mentioned as being capable of being prepared in a similar manner is 6-nitro benzoselenazyl, 6-nitro benzothiazyl 2 - selenide. Diselenazyl mono selenides such as dibenzoselenazyl 2-selenides may likewise be prepared by employing a 2-chlor selenazole instead of a 2-chlor thiazole; (9) 2-(carbethoxyselenyl) benzoselenazole <FOR