Patent GB-775017-A (GB)
Title: Synthetic ester lubricants and lubricating compositions therefrom
Inventor: EVANS GEORGE GAMBLE
IPC: C10M105/34
Filed: 1954-04-07
Abstract: The invention comprises an oleaginous fluid obtained by oxidizing a paraffin wax to obtain an acid fraction comprising C12-C26 acids and a non-acidic oxidized fraction, extracting the said acid fraction from the oxidized wax, and esterifying the said acid fraction with a saturated aliphatic alcohol.  The oxidation may be effected by blowing the wax with air, preferably at elevated temperature and in the presence of an oxidation catalyst.  If carried out for a sufficient length of time, the oxidation will result not only in the production of the said acid fraction but will also result in a complex mixture of esters, lactones and lactides which is difficult to hydrolyse. The acid fraction may be readily extracted by dissolving the total oxidized product in an organic solvent and extracting the acid portion with an alkaline agent, e.g. aqueous sodium carbonate. The acid fraction is released from the extract by acidification. The saturated aliphatic alcohols used for the esterification preferably contain 4 to 20 carbon atoms and have some branching of their chains.  The oxo alcohols are particularly suitable.  The esterification is preferably conducted at elevated temperature in the presence of an esterification catalyst such as sodium bisulphate and a water entrainer.  The resulting ester may be refined by treating with an inorganic base and washing to give a product of residual acidity less than 1 milligram KOH/g.  The yield of the esterified acids may be increased by adding selected alcohols or glycols to the wax during oxidation.  In an example, a charge of slack wax and cobalt naphthenate is blown with air for 48 hours at 120 DEG  C., the oxidized product is dissolved in ethyl acetate and extracted with an aqueous solution of sodium carbonate, the extract is acidified and the acid fraction so obtained is esterified with 2-ethylhexanol.  The product is useful as a lubricant and as a component in lubricating compositions. The non-acid fraction may also be used as a lubricant.  The Provisional Specification refers also to the use of predominantly paraffin, i.e. hydrocarbons having a molecular weight corresponding to more than 12 carbon atoms as starting materials for the oxidation.  Naphthenic hydrocarbons having paraffinic side chains are also mentioned.ALSO:Lubricating compositions comprise an oleaginous fluid, obtained (see Group IV(b)) by oxidizing a paraffin wax to obtain a C12-C26 acid fraction and a nonacidic oxidized fraction, extracting the acid fraction, and esterifying said acid fraction with a saturated aliphatic alcohol, blended with a mineral oil, a diester or complex ester, or a glycol ether.  The saturated aliphatic alcohol is preferably a branched-chain C4-C20 alcohol such as an oxo alcohol.  The lubricating compositions may also contain oxidation inhibitors such as phenols or alkylated phenols, organic sulphur and/or phosphorus-containing compounds, or amines, e.g. phospho-sulphurized hydrocarbons, particularly terpenes, and phenothiazine.  The non-acidic oxidized fraction may also be used in lubricating compositions similar to those described for the esterified acid fraction.  Exemplified compositions comprise an ester product, obtained by oxidizing slack wax and esterifying the extracted acidic fraction with 2 - ethyl hexanol, together with di-octyl sebacate or di-nonyl sebacate.