Patent GB-738073-A (GB)
Title: Lubricating oil composition
Inventor: LOWENSTEIN-LOM WALTER
IPC: C07F9/08
Filed: 1951-08-23
Abstract: As lubricating oil additives there are employed compounds containing phosphorus and sulphur wherein the phosphorus is present only as a phosphate, phosphite, thiophosphate or thiophosphite group and in which sulphur is present as the only hetero-atom in a heterocyclic group which is joined to the phosphate, phosphite, thiophosphate or thiophosphite group through an oxygen or sulphur atom adjacent to the phosphorus atom.  The phosphorus compound can have the formula <FORM:0738073/IV (b)/1> or <FORM:0738073/IV (b)/2> where the brackets represent optional groups, M represents a heterocyclic group containing sulphur as the only hetero-atom, X represents an oxygen or sulphur atom, R1 is an alkylene, arylene, aralkylene or alkarylene group or a direct carbon to oxygen linkage and R2 is an alkyl, aryl, aralkyl or alkaryl group or hydrogen and R3 and R4 can be groups of the formula R5-M-R6, wherein R5 is an alkarylene or aralkylene group and R6 is an alkaryl or aralkyl group, or R3 and R4 can be alkyl, aryl, aralkyl or alkaryl groups and are preferably alkyl groups each containing 1 to 20 or 2 to 10 carbon atoms.  Preferred heterocyclic groups are 1,2-thiapyran, 1,4-thiapyran, thianthrene, thionaphthene and especially thiophene groups.  The phosphites can be made by reacting with phosphorus trichloride or with, e.g., P2O3 or P2S3, or with pentavalent phosphorus compounds, e.g. phosphorus oxychloride, phosphorus pentasulphide, or phosphorus pentoxide, hydroxy compounds having the formula R2-M-R1-OH or HO-R1-M-R1-OH; other compounds are obtained by reacting a hydroxy-compound of the general formula R7-OH, wherein R7 is an alkyl, aryl, alkaryl or aralkyl group with an excess of one of the above phosphorus compounds.  In compounds containing both sulphur and oxygen atoms at X, the hydroxy compound is preferably reacted with the inorganic phosphorus reagent before reaction with the sulphur containing alcohol, e.g. diisopropyl 2-phenyl-thiophene-5-p-phenylene phosphite is prepared by first preparing diisopropyl chlorophosphite and then reacting this with 2-phenyl-5-p-hydroxyphenyl thiophene.  The hydroxy compounds are obtained by reacting a compound of the formula R2-M-R2 with an oxidizing agent such as potassium permanganate in alkaline solution, e.g. 2 - phenyl - 5 - p - hydroxyphenyl - thiophene is obtained by the oxidation of 2,5-diphenyl-thiophene.  In an example a product consisting mainly of a compound of the formula <FORM:0738073/IV (b)/3> is prepared by reacting phosphorus trichloride, n - butanol and 2 - phenyl - 5 - p - hydroxyphenyl thiophene in carbon tetrachloride and pyridine.ALSO:A lubricating oil composition comprises a major proportion of a lubricating oil, preferably a mineral lubricating oil, and a minor proportion of an oil-soluble chemical compound containing phosphorus and sulphur wherein the phosphorus is present only as a phosphate, phosphite, thiophosphate or thiophosphite group and in which sulphur is present as the only hetero-atom in a heterocyclic group which is joined to the phosphate, phosphite, thiophosphate or thiophosphite group through an oxygen or sulphur atom adjacent to the phosphorus atom.  The phosphorus compound can have the formul  <FORM:0738073/III/1> or <FORM:0738073/III/2> where the brackets represent optional groups, M represents a heterocyclic group containing sulphur as the only hetero-atom, X represents an oxygen or sulphur atom, R1 is an alkylene, arylene, aralkylene or alkarylene group or a direct carbon to oxygen linkage and R2 is an alkyl, aryl, aralkyl or alkaryl group or hydrogen, and R3 and R4 can be groups of the form R5-M-R6 wherein R5 is an alkarylene or aralkylene group and R6 is an alkaryl or aralkyl group, or R3 and R4 can be alkyl, aryl, aralkyl or alkaryl groups and are preferably alkyl groups each containing 1 to 20 or 2 to 10 carbon atoms.  Preferred heterocyclic groups are 1,2-thiopyran, 1,4-thiapyran, thianthrene, thionaphthene or particularly preferred, thiophene.  Preferably the molecular weight of the added compound does not exceed 1000 and especially suitable are compounds of molecular weight below 700.  In an example, one part of a compound of the formula <FORM:0738073/III/3> is blended with 99 parts of a phenol extracted coastal oil of turbine oil viscosity.  The preparation of the phosphorus compounds is described (see Group IV (b)).