Patent GB-694853-A (GB)
Title: Synthetic lubricating oil
IPC: C10M107/34
Filed: 1949-08-08
Abstract: Carbonate or thiocarbonate esters are made by reacting hydroxy compounds of formula XROH under esterification conditions with phosgene or thiophosgene or a lower alkyl carbonate or thiocarbonate. In the formula X is OH or preferably H and R is an organic group consisting of a series of aliphatic hydrocarbon groups interlinked by 2 to 25 O atoms, each pair of O atoms in the molecule being separated by a chain of at least 2 C atoms, the average ratio of all hydrocarbon groups in the molecule of the type -CH2-CH2- to similar groups in which at least one of the H atoms is replaced by a hydrocarbon radicle being no greater than 3 : 1, the total number of C atoms in the entire R group being from 5 to 85.  The reaction with phosgene or thiophosgene may be effected in the presence of an organic base such as pyridine.  Diethyl carbonate is a specified lower alkyl carbonate.  Hydroxy compounds may be ether-alcohols prepared by reacting a monohydric aliphatic alcohol with an alkylene oxide, e.g. propylene oxide, butylene oxide, butadiene monoxide or tetrahydrofurane, so that products containing 2 or more ether oxygen atoms are obtained.  Ethylene oxide may also be used admixed with higher oxides to the limited extent imposed by the 3 : 1 ratio in the definition of R.  Preferably the aliphatic alcohol is saturated and contains 1-20, especially 1-10, C atoms and it is reacted with 2-20, especially 8-20, mol. proportions of the oxide.  The esters are lubricants and should have a molecular weight of at least 300 and a viscosity of not more than 40 centistokes at 210 DEG  F. Antioxidants such as a -naphthylamine may be incorporated. Representative of specified hydroxy compounds are: dipropylene glycol monomethyl ether, tripropylene glycol mono-n-butyl ether, "Dowanols" and "Carbitols."  Ether glycols which may be used are of formula <FORM:0694853/IV (b)/1> where either R1 or R2 is Me and the other H and n is 2-20.  More than one but not more than 2 mols. of phosgene or thiophosgene are used for every 2 mols. of polyether glycol. Desirably an organic base such as phosgene is present.  In examples: (1) n-butanol is treated with propylene oxide in the presence of boron fluoride-ethyl ether and the product with diethyl carbonate in toluene in the presence of a small quantity of sodium methoxide; and (2) n-butanol is treated with propylene oxide in the presence of boron fluoride and the product with phosgene in the presence of pyridine.  The Specification as open to inspection under Sect. 91 comprises glycols containing one or more ether groups which may be used in the preparation of carbonates and thiocarbonates and amongst specified compounds are:-propylene glycol mono-n-dodecyl thioether and mono-n-butyl ether, di-, tri- and tetra-propylene glycol mono-tert.-octyl thioethers and "Cellosolves," the word "Cellosolve" being a Registered Trade Mark.  This subject-matter does not appear in the Specification as accepted.ALSO:Carbonate or thiocarbonate esters of hydroxy compounds of formula XROH are lubricants and may be used in grease compositions or blended with mineral oils.  In the formula X is OH or preferably H and R is an organic group consisting of a series of aliphatic hydrocarbon groups interlinked by 2-25 O atoms, each pair of O atoms in the molecule being separated by a chain of at least two C atoms, the average ratio of all hydrocarbon groups in the molecule of the type -CH2-CH2-to similar groups in which at least one of the H atoms is replaced by a hydrocarbon radicle being not greater than 3:1, the total number of C atoms in the entire R group being from 5-85.  Hydroxy compounds may be ether alcohols made by reacting a monohydric aliphatic alcohol with an alkylene oxide, e.g. propylene oxide, butylene oxide, butadiene monoxide or tetrahydrofurane, so that products containing two or more ether O atoms are obtained.  Ethylene oxide may be used admixed with higher oxides to the limited extent imposed by the 3:1 ratio in the definition of R.  Preferably the aliphatic alcohol is saturated and contains 1-20, especially 1-10, C atoms and it is reacted with 2-20, especially 8-20, mol preparations of the oxide.  Hydroxy compounds specified are dipropylene glycol monomethyl ether, tripropylene glycol mono-n-butyl ether, "Dowanols" and "Carbitols".  Ether glycols which may be used are of formula <FORM:0694853/III/1> where either R1 or R2 is Me and the other H and n is 2-20.  For the preparation of the esters see Group IV(b).  The esters should have a molecular weight of at least 300 and a viscosity of not more than 40 centistokes at 210 DEG F. Antioxidants, e.g. \s1 naphthylamine, and detergents may also be present.  In examples (1) and (2) carbonates are made from a reaction product of n-butanol and propylene oxide. The Specification, as open to inspection under Sect. 91, refers to the use of glycols containing one or more ether groups in the preparation of carbonates and thiocarbonates and amongst specified compounds are propylene glycol mono-n-dodecyl thioether and mono-n-butyl ether, di-, tri- and tetra-propylene glycol mono-tert-octyl thioethers, and "Cellosolves," the word "Cellosolve" being a Registered Trade Mark.  This subject-matter does not appear in the Specification as accepted.