Patent GB-636552-A (GB)
Title: Improvements in or relating to the production of double salts and to hydrocarbon compositions containing them
IPC: C07F9/08
Filed: 1947-04-03
Abstract: Substantially non-aromatic hydrocarbon materials such as lubricating greases, hydrocarbon polymers, hydraulic fluids, motor fuels, or additive concentrates for such substances are inhibited against oxidation by incorporating in them minor proportions, e.g. 0.1 to 1.0 per cent of a double salt of a metal alkyl xanthate of a metal from group I or II of the Periodic Table in which the alkyl group contains at least 2 carbon atoms and a metal organo thiophosphate or thiophosphite having the formula [(RX)2PS2]nM or [(RX)2PS]nM respectively, in each of which R represents an alkyl radical containing at least 5 carbon atoms and preferably 5-18 carbon atoms, or an alkaryl radical containing at least one alkyl side chain having at least 4 carbon atoms, X represents a non-metallic element from Group VI of the Periodic Table, preferably oxygen, M is a metal of Group I or II of the Periodic Table, and n is a number equal to the valence of the metal M (see Group IV (b)). The metal alkyl xanthate may be zinc isopropyl xanthate, zinc ethyl xanthate, zinc iso-octyl thioxanthate, potassium butyl xanthate, potassium amyl xanthate, barium cetyl thio-xanthate, and cadmium lauryl xanthate; and the radical R may be the mixture of alcohols containing 12-16 carbon atoms in the molecule obtained from the hydrogenation of coconut oil, or 2 ethyl n-hexyl alcohol or tertiary octyl phenol.  The preferred thiophosphorus compounds contain about 5-18 carbon atom alkyl groups connected through oxygen to phosphorus, e.g. zinc or barium 2-ethylhexyl thiophosphite and thiophosphate.  The double salts may be employed in hydrocarbon lubricating oils in conjunction with various known detergent or other type additives and the base stocks may be residuals or distillates derived from paraffinic, naphthenic, asphaltic or mixed base crude petroleums or blended oils, and particularly de-asphalted oils.  The oils may also have been obtained from shale oil.  The oils may have been refined by any of the usual processes, or may be hydrogenated or synthetic oils. Minor proportions of fatty oils or hydrogenated or voltolized fatty oils may be present.  The mineral oil double salt compositions may contain solubilizing and defoaming agents such as the higher alcohols having 8 or more carbon atoms and preferably 12 to 20 carbon atoms, e.g. saturated straight or branched chain aliphatic alcohols such as octyl alcohol, lauryl alcohol, cetyl alcohol or octadecyl alcohol, the corresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols, such as naphthenic alcohols; and aryl substituted alkyl alcohols, for instance, phenyl octyl alcohol, or octadecyl benzyl alcohol.  The alcohols may be substantially pure synthetic alcohols or mixtures of alcohols from natural sources such as wool fat or sperm oil. Alternatively, the wool fat or sperm oil may be used as such. Instead of preparing the double salts by simply heating the reactants together (see Group IV (b)), they may be prepared by heating the reactants together in an inert organic medium such as mineral oil until complete solution has taken place.  The solution thus obtained and containing, for example, 25 to 50 per cent of the double salts may be employed as a concentrate suitable for incorporation in the mineral oil base.  Test results are given.ALSO:Double salts are obtained by reacting a metal alkyl xanthate of a metal from Group I or II of the Periodic Table, and having an alkyl group containing at least 2 carbon atoms, with a metal organo thiophosphate or thiophosphite [(RX)2PS2]nM or [RX)2PS]nM, respectively, in which R represents an alkyl radical containing at least 5 carbon atoms, or an alkaryl radical containing at least one alkyl side chain having at least 4 carbon atoms, X represents a non-metallic element of Group VI of the Periodic Table, M is a metal of Group I or II of the Periodic Table, and n is the valence of M.  About 10-25 per cent of the xanthate may be used in the total mixture.  In a series of examples, double salts of zinc isopropyl xanthate and thiophosphorus compounds are prepared by heating 1 part by weight of the xanthate with three parts by weight of the phosphorus compound at 100-110 DEG  C. with stirring, until a homogeneous solution is obtained, and the product is then filtered to remove a slight amount of insoluble material.  Descriptions are given of the preparation by the usual methods of zinc and barium 2-ethyl-n-hexyl thiophosphites, of barium 2-ethyl-n-hexyl thiophosphate, of zinc thiophosphite and the thiophosphate of a commercial mixture of 12-16 carbon atom straight chain alcohols, and of zinc tertiary octyl phenyl thiophosphate.  The above phosphorus compounds are used in the preparation of the double salts.  The reactants may be heated together in an inert organic medium such as mineral oil to form a concentrate suitable for addition to lubricants.  The double salts of the invention are said to be useful as antioxidants in substantially non-aromatic hydrocarbon materials such as mineral lubricating oils (see Group III) and rubbers (see Group V).ALSO:Substantially non-aromatic hydrocarbon polymers and natural and synthetic rubbers are preserved by the incorporation of minor proportions of double salts prepared by reacting together a metal alkyl xanthate of a metal from Group I or II of the Periodic Table, and having an alkyl group containing at least 2 carbon atoms, and a metal organic thiophosphate or thiophosphite [(RX)2PS2nM or [(RX)2PS]nM respectively, in which R represents an alkyl radical containing at least 5 carbon atoms, or an alkaryl radical containing at least one alkyl side chain having at least 4 carbon atoms, X represents a non-metallic element of group VI of the Periodic Table, M is a metal of group I or II of the Periodic Table, and n is its valency, (see Group IV (b)).  The metal alkyl xanthate may be zinc isopropyl xanthate and the radical R may represent either the mixture of alcohols containing 12-16 carbon atoms in the molecule obtained from the hydrogenation of coconut oil or 2 ethyl n-hexyl alcohol or tertiary octyl phenol.  Other examples are given also.