Patent GB-717591-A (GB)
Title: Improvements in or relating to sulphur-containing polycarboxylates and to hydrocarbon oil compositions
IPC: F02B47/00
Filed: 1951-10-15
Abstract: A polycarboxylate of formula <FORM:0717591/IV (a)/1> H where R is a butyl or amyl group, X is an alkyl group of 1 to 18 C atoms and n is 10 to 50 is made by contacting an alkyl mercaptan of 1 to 18 C atoms with butyl or amyl acrylate in the presence of a polymerization catalyst which liberates free radicles under the conditions of the reaction.  Representative of many mercaptans specified are methyl, isopropyl, tert. butyl, 2-ethylhexyl and octadecyl mercaptan. Temperatures of up to about 125 DEG C. may be used.  Reaction times of several hours to several days are quoted. Up to 10 per cent. of catalyst base on ester may be used, 0.1-7 per cent. being preferred. Preferably a molecular excess of ester in relation to mercaptan is used, e.g. ratios of 5/1 and 1000/1 by weight are mentioned. Diluents may be used, those specified being water in the presence of an emulsifying agent, chlorbenzene, ether, acetone and hexane. Specified catalysts are peroxygen-type compounds, e.g. benzoyl and stearoyl peroxides, tert. butyl and cumene hydroperoxides, hydrogen peroxide, sodium perborate, potassium persulphate, alkali percarbonates; hydrazine derivatives such as the hydrochloride and dibenzoyl hydrazine and organometallic compounds such as tetraethyl lead.  U.V. light may be used with the above catalysts or as the sole catalyst.  The products may be used as antifoaming agents for hydrocarbon oils, (see Group III).  In examples polycarboxylates are made from tert. butyl or tert. dodecyl mercaptans and butyl or amyl acrylates.ALSO:A polycarboxylate of formula <FORM:0717591/IV (b)/1> where R is a butyl or amyl group, X is an alkyl group of 1 to 18 C atoms and n is 10 to 50 is made by contacting an alkyl mercaptan of 1 to 18 C atoms with butyl or amyl acrylate in the presence of a polymerization catalyst which liberates free radicles under the conditions of the reaction.  Representative of many mercaptans specified are methyl, isopropyl, tert. butyl, 2-ethylhexyl and octadecyl mercaptan.  Temperatures of up to about 125 DEG  C. may be used.  Reaction times of several hours to several days are quoted. Up to 10 per cent of catalyst bond on ester may be used, 0.1-7 per cent being preferred.  Preferably a molecular excess of ester in relation to mercaptan is used, e.g. ratios of 5/1 and 1000/1 by weight are mentioned.  Diluents may be used, those specified being water in the presence of an emulsifying agent, chlorobenzene, ether, acetone and hexane.  Specified catalysts are peroxygen-type compounds, e.g. benzoyl and stearoyl peroxides, tert. butyl and cumene hydroperoxides, hydrogen peroxide, sodium perborate, potassium persulphate, alkali percarbonates; hydrazine derivates such as the hydrochloride and dibenzoyl hydrazine and organometallic compounds such as tetraethyl lead.  Ultra-violet light may be used with the above catalysts or as the sole catalyst.  The products may be used as anti-foaming agents for hydrocarbon oils (see Group III).  In examples polycarboxylates are prepared by reacting tert. butyl or tert. dodecyl mercaptan with butyl or amyl acrylates in the presence of benzoyl peroxide and benzene or Stoddard solvent.  Specification 579,353 is referred to.ALSO:The foam susceptibility of hydrocarbon oils is decreased by incorporating therewith up to 0.1 per cent. by weight of a mercaptopolycarboxylate of formula <FORM:0717591/III/1> where R is a butyl or amyl group, X is an alkyl group of 1 to 18 C atoms and n is 10 to 50 and which has a sulphur content of 0.1 to 0.2 per cent.  The polycarboxylate is made by reacting an alkyl mercaptan of 1 to 18 C atoms with butyl or amyl acrylate in the presence of a polymerization catalyst which liberates free radicles under the conditions of the reaction.  Representative of many specified mercaptans are methyl, isopropyl, tert. butyl, 2-ethythexyl and octadecyl mercaptan.  Catalysts specified are peroxygen-type compounds, hyrdazine derivatives and organo-metallic compounds. Inert diluents may be present.  For reaction details see Group IV (b).  Hydrocarbon oil concentrates containing up to 50 per cent. of polycarboxylate may be made. Oils mentioned are lubricating oils, Diesel fuels and lubricants, and pressure tranfer media, e.g. hydraulic oils.  Other adjuvants may be present in the oil, e.g. foam inducing additives. Additional additives mentioned are metal salts of a cycloaliphatic aromatic or aromatic-aliphatic compound containing as substituents a salt-forming radicle and a hydrocarbon chain of at least 4 C atoms.  The salt-forming group may be OH, COOH, PO4H, PO3H, SH, or SO3H and many metals are specified representative being Ba, Al, Cu, Na, Cd and Mn.  Preferred are aluminium and alkaline earth metals.  Other additives mentioned are aluminium, calcium or lithium, hexadecyl phenate, barium or magnesium salts of sulphated dodecylphenol, magnesium or strontium salts of an alkyl-substituted naphthol the alkyl substituent being derived from wax, the barium salt of oleyl carbonate, barium cetyl phthalate, the calcium salt of wax-substituted phenoxyphenol, the barium salt of wax-substituted and sulphated hydroxydiphenyl sulphide, aromatic and alkyl-aromatic compounds of 5-30 C atoms containing a thiocarbonate group, e.g. of formula <FORM:0717591/III/2> where R11 is a chlorine-containing alkyl, aryl or aralkyl radicle of 5-30 C atoms, R1 is an organic ester-forming group and Y is S or O at least one Y being S.  Many of the latter compounds are specified representative being chlorododecyl ethyl, chlorobenzyl methyl and tetrachloro-phenyl 2-ethyl-hexyl xanthates, trichlorobenzyl ethyl and chloronaphthyl methyl sulphocarbonates, (di-chlorophenyl)-ethyl propyl and chlorooctadecyl amyl trithiocarbonates, tetrachlorohexyl p-tolyl and chlorononocosyl ethyl dithiocarbonate and chlorobenzyl dodecyl and chloroamyl benzyl thiocarbonate.  Xanthates are generally advantageous especially those of formula <FORM:0717591/III/3> where R1 and R11 are as above and particularly where R1 is an alkyl group of 1-4 carbon atoms. Examples (2)-(5) relate to antifoaming and stability tests on base oils containing 2-50 p.p.m. of adducts obtained from tert. butyl or tert. dodecyl mercaptan and butyl or amyl acrylate with and without 4 per cent. of a barium salt of an alkyl aromatic sulphonic acid containing 22-30 C atoms in the alkyl group.  Specification 579,353, [Group IV], is referred to.