Patent GB-636118-A (GB)
Title: Improvements in or relating to extreme pressure lubricants
Filed: 1946-10-08
Abstract: Chlorinated hydrocarbon esters of hydrocarbon substituted dithiocarbamic acids of general formula RR1NCSSR11Hal(x-1), when blended with mineral lubricating oils in amounts varying from 2 to 30 per cent, preferably about 10 per cent, yield extreme pressure lubricants. In the above formula R and R1 may be hydrogen, aliphatic or aromatic hydrocarbon radicles, at least one of them must be a hydrocarbon radicle and they may be the terminal hydrocarbon groups of a hydrocarbon chain such as when RR1N is the piperidyl radicle, R11 is an aliphatic hydrocarbon residue such as may be obtained from paraffin wax, kerosene and other petroleum fractions having from 8-30 carbon atoms in the molecule, Hal is a halogen, preferably chlorine, and x is a positive number preferably chosen so that the halide R11Hal from which they are derived (for preparation see Group IV (b)) contains from 5 to 50 per cent, preferably 25-35 per cent, weight per cent of halogen.  Any low pour point lubricating oil may be used in the blend but a Pennsylvania type oil of viscosity from about 50 to 150 secs. S.U.S. at 210 DEG  F., and a cold test below 0 DEG  F., is preferred.  In examples, a 10 per cent blend of esters derived from chlorinated kerosene and (1) sodium-piperidyl-dithioformate; (2) sodium-diamylamino-dithioformate; and (3) sodium-xylidyl-dithioformate with a mineral lubricating oil of viscosity 45 secs. at 210 DEG  F. carry a full shock load of 15 weights in the Almen test and a table is given illustrating the smaller extent of corrosion obtained by using the above blends as compared with a conventional extreme pressure additive containing sulphur and chlorine but no nitrogen.ALSO:Halo-substituted dithiocarbamates are obtained by reacting an alkali metal salt of a hydrocarbon substituted dithiocarbamic acid with a stoichiometric excess, based on halogen, of a halogenated aliphatic hydrocarbon containing from 8-30 carbon atoms and at least 2 labile halogen atoms in the molecule.  The reaction may be represented:-RR1NCSSMet + R11Halx---> RR1NCSSR11Hal(x - 1)+MetHal wherein R and R1 may be alkyl, cycloalkyl, aryl, aralkyl, alkenyl or hydrogen, e.g. methyl, ethyl, propyl, amyl, cyclopentyl, cyclohexyl, phenyl, benzyl and xylyl at least one of them being a hydrocarbon radicle or both may be the terminal hydrocarbon groups of a hydrocarbon chain as in piperidyl dithioformic acid, R11 is an aliphatic hydrocarbon residue which may be derived from a petroleum mineral oil distillate such as paraffin wax, kerosene and other petroleum fractions having from 8-30 carbon atoms in the molecule, Met is an alkali metal such as sodium, potassium and lithium, Hal is a halogen, preferably chlorine and x is a positive number, preferably chosen to give a weight per cent of halogen in the compound R11Halx ranging between 5 and 50 per cent, preferably 25-35 per cent.  The reaction may be performed in boiling organic solvents such as acetone or methyl ethyl ketone although ethyl alcohol may not be used.  The alkali metal salt of the dithiocarbamic acid is made by reacting a primary or secondary amine with carbon disulphide and alkali metal hydroxides in the usual manner.  In examples an alkali metal dithioaminoformate is prepared by reacting carbon disulphide with cold (1) piperidine; (2) diamyl amine, and (3) mixed xylidines dissolved in methyl ethyl ketone containing powdered sodium hydroxide, chlorinated kerosene containing 39.8 per cent of chlorine is then added and the mixture refluxed for two hours when the product is isolated by filtration from sodium chloride and removal of the solvent under reduced pressure.