GB761296A - Improvements in or relating to methylene ether esters as synthetic lubricants - Google Patents

Abstract

The invention comprises methylene ether esters of the general formula R(OCH2OOCR1)x, wherein R is an organic group derived from an aliphatic monohydric alcohol or a glycol, R1 is derived from an aliphatic monocarboxylic acid, and x is 1 or 2, and wherein the total number of carbon atoms in the methylene ester is between 20 and 130, and wherein the methylene ester has an A.S.T.M. pour point below 35 DEG F., a flash point above 300 DEG F. and a kinematic viscosity at 210 DEG F. within the range of 2 to 60 centistokes. The alcohols from which the group R is derived may be oxo alcohols (particularly those having from 8 to 20 carbon atoms) and alcohols derived from the Guerbet and Aldol reactions-particularly with oxo alcohols (the Guerbet and Aldol reactions are referred to below). Suitable glycols and polyglycols from which R is derived are polyalkylene glycols particularly polymethylene glycols such as butanediol-1,4, pentanediol-1,5, 2,3-butylene glycol, 1,3-butylene glycol, 2-alkoxymethyl-2,4-dimethyl-pentanediol-1,5, hexylene glycol, 2,4-pentanediol and decanediol-1,10, and mixtures thereof. Suitable monocarboxylic acids from which R1 may be derived are acetic, propionic, butyric, 2-ethylbutyric, caprylic, 2-ethylhexanoic, caproic, pelargonic, lauric, myristic, oleic, stearic, glycollic, lactic, a hydroxystearic, a methoxypropionic, an ethoxyethoxyacetic, mono-C8-oxo-sebacate, and mono-2-ethylhexyl adipate acids, C3-C30-oxo acids including bottom acids, acids derived from petroleum fractions by oxidation, and acids derived from alcohols by alkali fusion. When x represents 1 in the above general formula, the desired compound may be prepared by (1) forming the chloromethyl ether of the required monohydric alcohol by reacting the alcohol with formaldehyde in the presence of hydrogen chloride, or by chlorinating the required methyl ether of the required monohydric alcohol, and the chloromethyl ether thus formed is reacted with the required carboxylic acid; or (2) reacting the required monohydric alcohol with one molar proportion of formaldehyde to form a hemi-formal which is then reacted with the required carboxylic acid chloride. In the examples (1) a tridecyloxymethyl stearate is prepared by reacting a C13-oxo alcohol, trioxymethylene and hydrogen chloride to form C13-oxo chloromethyl ether which is then reacted with stearic acid; (2) tridecyloxymethyl pelargonate is obtained as in (1) by first preparing tridecyl chloromethyl ether and then reacting it with pelargonic acid; and (3) a compound of the formula <FORM:0761296/IV(b)/1> is obtained by condensing ethylene glycol with trioxymethylene in the presence of hydrogen chloride to form a bis chloromethyl compound of the formula ClCH2OCH2CH2OCH2Cl and then reacting it with two equivalents of C13-oxo acids. Starting materials. Alcohols containing branched chains are prepared by either of the following methods: (1) The Guerbet reaction which is an alkaline condensation of primary or secondary alcohols and requires the presence of a methylene group adjacent to the carbinol group. The sodium alcoholate of the reacting alcohol is generally used as catalyst, metallic sodium being preferably added to the reaction mixture to form an alcoholate at the beginning of the reaction. Other alkaline agents such as sodium soaps, sodium borate or sodium allyl borate may also be used. The presence of a hydrogenating catalyst such as copper, zinc or nickel improves the yield of desired alcohol. An oxo alcohol is a suitable reactant for the Guerbet reaction. The Specification describes in detail the condensation of a C8-oxo alcohol in the presence of sodium hydroxide and copper powder. (2) The Aldol condensation which is the condensation of an aldehyde, e.g. a C8-oxo aldehyde, containing a methylene group adjacent to the carbonyl group in the presence of an alcohol and acid to form a b -hydroxy-aldehyde which is then dehydrated and hydrogenated. The aldehyde reactant must contain a methylene group adjacent to the carbonyl group.ALSO:Lubricating compositions comprise methylene esters having the general formula R(OCH2OOCR1)x wherein R is an organic group derived from an aliphatic monohydric alcohol or glycol, or a mixture of such alcohols or glycols, R1 is derived from an aliphatic monocarboxylic acid, x is 1 or 2 and the total number of carbon atoms in the methylene ester is between 20 and 130, the said methylene ester having an A.S.T.M. pour point below 35 DEG F., a flash point above 300 DEG F., and a kinematic viscosity at 210 DEG F. within the range of 2 to 60 centistokes. The above methylene esters may be added to natural or synthetic lubricating oils e.g., they may be blended with monoesters, with dibasic acid esters such as esters of adipic, sebacic, glutaric and succinic acids, with complex esters such as the alcohol-dibasic acid - glycol - dibasic acid -alcohol complex esters, and with mineral oils or polymerized hydrocarbons. The above methylene esters may be thickened by the addition of grease forming soaps such as lithium stearate or sodium hydroxy stearate, or by the addition of viscosity index improvers of the fumarate ester-vinyl ester polymer of methacrylate polymer type e.g., from 0.5 to 10 per cent by weight of a copolymer of acrylate or methacrylate esters having an ester chain length of 8 to 18 carbon atoms may be blended with the methylene esters. The methylene esters are compatible with pour point improvers such as polybutene, detergents, oxidation inhibitors and rust inhibitors. They may also be added to fuel oils.