Patent GB-647911-A (GB)
Title: Improved lubricating compositions and preparation of polymers for use therein
IPC: C08G75/00
Filed: 1947-10-03
Abstract: Polymers suitable for use as lubricants are prepared by polymerizing an alkyl thioether or disulphide having the formula HO-R-(S)p-R-OH, where p is 1 or 2, and R is an organic radical, in the presence of a dehydration catalyst.  Specified thioethers are bis-(2-hydroxyethyl), bis-(3-hydroxyamyl), bis - (6 - hydroxyhexyl), bis - (7 - hydroxyheptyl), bis - (6 - hydroxyhexyl), bis - (7 - hydroxyheptyl), bis-(8-hydroxyoctyl), bis-(9-hydroxynonyl), bis - (10 - hydroxydecyl) and bis-(12-hydroxydodecyl) sulphides and their homologues, 2 - hydroxyethyl - 2 - hydroxy-propyl, 2 - hydroxyethyl - 3 - hydroxypropyl sulphides and their homologues, bis-(1-methyl-2 - hydroxyethyl), bis - (1 - methyl - 3 - hydroxypropyl) sulphides and their homologues, (1-methyl-2-hydroxyethyl) (1-methyl-3-hydroxypropyl) sulphide, bis-(1,2-dimethyl-3-hydroxypropyl, sulphide and its homologues, bis-(di-methyl-hydroxymethyl) and bis-(1,1-dimethyl-2-hydroxyethyl) sulphides, (2-hydroxyethyl) (1 - methyl - 2 - hydroxyethyl), (2 - hydroxyethyl) (1,1 - dimethyl - 2 - hydroxyethyl) and (1 - methyl - 2 - hydroxyethyl) (1,1 - dimethyl - 2-hydroxyethyl) sulphides. Disulphides specified are bis-(g -hydroxypropyl), bis-(b -hydroxyethyl) and bis-(b -hydroxypropyl) disulphides.  Suitable catalysts are concentrated sulphuric, nitric, hydrochloric, hydrobromic and hydroiodic acids, p-toluene sulphonic acid, aluminium chloride and boron trifluoride.  Polymerization may be effected in liquid, solution, emulsion or gaseous phases, using diluents which may be liquid, e.g. dihydronaphthalenes, decahydronaphthalene, cycloheptane, 2,2,3-trimethylpentane, 2-methyl-3-ethylpentane, 2,4-dimethylheptane, 4-ethylheptane, 2-methyloctane, 2,6-dimethyloctane, 2,4,5,7-tetramethyloctane, 2-methylnonane and dihexyl, or gaseous, e.g. methane, ethane, propane and butane, at temperatures between 150 DEG  and 300 DEG  C.  Alcohols may be present to etherify the polymers.  Water may be removed by distillation or by dehydrating agents.  Diluent removed by azeotropic distillation is preferably replaced to maintain a constant diluent/monomer ratio.  After removal of catalyst the product is dehydrogenated and decolourized by percolation of solutions in benzene or toluene through fuller's earth or activated clays, followed by hydrogenation using a tungsten sulphide catalyst.  The terminal hydroxyl groups of the polymers may be partially or completely esterified, e.g. to form nitrates, phosphates, sulphates or fatty acid esters, or etherified, using alkyl, aralkyl, alkoxyalkyl or alkylene halides or sodium monochloracetate, during or after polymerization.  The products may be soluble in water, alcohols, esters, ethers and aromatic hydrocarbons.  They are suitable for use as hydraulic brake fluids, grease bases, plasticizers for cellulose esters, e.g. nitrocellulose, and ethers, polymethacrylates and phenol-formaldehyde resins, extreme pressure additives for lubricating oils and, admixed with minor amounts of oxidation inhibitors, corrosion inhibitors or gelling agents, e.g. phenyl-a -naphthylamine, as lubricants.ALSO:Bis-(g -hydroxypropyl)-sulphide is prepared by exposing a mixture of allyl alcohol and hydrogen sulphide in a quartz tube to ultra-violet light and subjecting the product to fractional distillation.  Similar thioethers may be prepared from methallyl, crotyl and isopropenyl alcohols.  Bis - (b  - hydroxy - a  - methylethyl) - sulphide is prepared by heating at 100 DEG  C. in an autoclave a mixture of allyl alcohol, hydrogen sulphide and di-n-butylamine as catalyst and fractionating.  b  - hydroxy - a  - methylethyl mercaptan is obtained as a by-product.  Bis-(g -hydroxypropyl)-disulphide is prepared by adding iodine dropwise to an aqueous solution of g -mercaptopropyl alcohol and potassium hydroxide, washing the product and fractionally distilling.