Patent GB-1042902-A (GB)
Title: New thiomorpholinocarbodithioic acid derivatives and their use as vulcanisation accelerators
Inventor: AYAD KAMAL NAGUIB
IPC: C08K5/00
Filed: 1964-02-28
Abstract: The invention comprises thiomorpholinocarbodithioc acid derivatives having the formula <FORM:1042902/C2/1> wherein Q represents (i) a salt-forming atom or group and X is an integer determined by the valency of Q; (ii) a group <FORM:1042902/C2/2> where n is 0 or 1 and x is 1; (iii) the group <FORM:1042902/C2/3> in which R1 is hydrogen, an esterifying group or a salt forming atom or group and x is 2; or (iv) the group <FORM:1042902/C2/4> where m is 0 or 1, x is 1, Y and Z are each a hydrogen atom or an alkyl group, or where Y and Z together with the carbon atoms to which they are shown linked form an aromatic ring, and where the thiomorpholine ring or rings can optionally contain one or more substituents. When the products are of type (i), that is metallic salts, specified metals are alkali metals, for example sodium and potassium, metals from Group II of the periodic table, for example calcium, zinc and cadmium, and other metals, for example nickel and manganese.  The products may be of type (i) wherein Q is an amine, specified amines being the thiomorpholine from which the thiomorpholinocarbodithioc acid itself is derived, or a tertiary aliphatic amine, for example triethylamine.  When the product is of type (iii), the esterifying group may be aliphatic or aromatic and is preferably a lower alkyl group, for example methyl, ethyl, but it may also be a cycloalkyl, an aralkyl or an aryl group. Products of type (iii) may also be salts wherein R1 is a metal, for example zinc, or an amine, for example thiomorpholine or diphenyl guanidine.  When the product is of type (iv) and Y or Z in the above formula represents an alkyl group, such a group may be for example a methyl or ethyl group.  Preferred compounds are those in which Y and Z together with the two carbon atoms to which they are shown linked form an aromatic ring, particularly a benzene ring, such compounds being the thiomorpholino thiocarbonyl benzthiazyl mono- and di-sulphides.  In compounds where the thiomorpholine ring or rings contain a substituent, the latter may be a hydrocarbon group or a halogen atom, for example chlorine. Preferred substituents are lower alkyl groups containing not more than 4 carbon atoms, for example methyl and ethyl. Specified compounds are sodium, zinc and thiomorpholinium thiomorpholinocarbodithioates, bis(thiomorpholino thiocarbonyl) mono- and disulphides, 2,6 - dimethylthiomorpholinium (2,6 - dimethyl-thiomorpholino)carbodithioate, bis ( 2,6 - dimethylthiomorpholinothiocarbonyl) disulphide, methyl bis (thiomorpholinothiocarbonylthio) acetate, and thiomorpholinothiocarbonyl benzthiazyl mono- and di-sulphides. Salts of type (i) may be prepared by mixing thiomorpholine with carbon disulphide at or near room temperature, and adding, preferably in stoichiometric amounts, thiomorpholine, and either a tertiary amine or an aqueous solution of sodium hydroxide.  The bis(thiomorpholinothiocarbonyl) mono- and di-sulphides are obtained by oxidizing an aqueous solution of an alkali metal thiomorpholino carbodithioate with a suitable water soluble agent, for example a water soluble cyanide such as potassium cyanide to give the mono-sulphide or with chlorine or a water soluble persulphate such as ammonium or potassium persulphate to give the disulphide. Also, a bis(thiomorpholinothiocarbonyl)monosulphide may be prepared from the appropriate disulphide by the action of a cyanide on the latter.  The reaction is suitably conducted in an aqueous-organic solvent medium in which the organic solvent is water-miscible, for example methanol, ethanol or acetone.  A bis(thiomorpholinothiocarbonylthio) acetic acid or ester is obtained by the action of an alkali metal salt of a thiomorpholinocarbodithioic acid on a dihalo- (particularly a dichloro-) acetic acid or ester respectively, preferably in an inert organic solvent, for example acetone at an elevated temperature. Thiomorpholinothiocarbonyl thiazyl disulphides may be obtained by condensing the appropriate thiazyl sulphur chloride with an anhydrous alkali metal salt of type (i).  The corresponding monosulphides are prepared by the double decomposition of the appropriate thiazyl disulphide with a bis(thiomorpholinothiocarbonyl)disulphide in the presence of a cyanide, for example potassium cyanide.  The products have applications in the acceleration of the vulcanization of rubber (see Division C3).ALSO:Natural and synthetic rubbers may be vulcanized by the addition of a vulcanization accelerator of the formula <FORM:1042902/C3/1> where Q represents (i) a salt forming atom or group and x is an integer determined by the value of Q; (ii) a group <FORM:1042902/C3/2> where n is 0 or 1 and x is 1; (iii) the group >CHCOOR1 in which R1 is hydrogen, an esterifying group or a salt-forming atom or group and x is 2; or (iv) the group <FORM:1042902/C3/3> where m is 0 or 1, x is 1, Y and Z are each a hydrogen atom or an alkyl group, or where Y and Z together with the carbon atoms to which they are shown linked form an aromatic ring, and where the thiomorpholine ring or rings may contain one or more substituents. The accelerators are generally used in conjunction with sulphur or a sulphur-containing vulcanizing agent, e.g. an amine disulphide, and with other conventional ingredients.