Patent GB-635708-A (GB)
Title: Improvements in or relating to methods of making organic hydroxy esters, and the improved organic hydroxy esters resulting therefrom and the improved compounded lubricants including the improved organic hydroxy esters
IPC: C10M135/26
Filed: 1947-02-05
Abstract: Additives for lubricating oils comprise hydroxy esters produced by esterifying the partial ester of a di- or poly-hydric alcohol with a fatty acid of at least 6 carbon atoms with an aliphatic hydroxy polycarboxylic acid containing not more than 3 carboxyl groups and not more than 6 carbon atoms and having at least 1 hydroxyl group not more than 2 carbon atoms removed from a carboxyl group, the proportions of reactants being such that the number of free hydroxyl groups of the partial ester is equal to the number of carboxyl groups in the aliphatic hydroxy acid.  The fatty acid preferably contains 10-20 carbon atoms.  Mineral oil for cutting may contain 1 per cent of the esters, e.g. di-(glycol mono-laurate, stearate or oleate)-malate, tartrate or citrate.  In general, lubricants contain 1-10 per cent.  Other ingredients, such as chloroalkyl esters of alkyl xanthates, sulphurized sperm or lard oil, and tricresyl phosphate may be added.  The Specification as open to inspection under Sect. 91, comprises also acid esters made by varying the proportion of hydroxy polycarboxylic acid used, e.g. mono-(glycol monooleate)-malate. This subject-matter does not appear in the Specification as accepted.ALSO:Hydroxy esters which are plasticizers for synthetic resins and rubber, and which impart tackiness to synthetic rubber, e.g. butadienestyrene copolymer, are produced by esterifying the partial ester of a di- or poly-hydric alcohol with a fatty acid of at least 6 carbon atoms with an aliphatic hydroxy polycarboxylic acid containing not more than 3 carboxyl groups and not more than 6 carbon atoms and having at least 1 hydroxyl group not more than 2 carbon atoms removed from a carboxyl group, the proportions of reactants being such that the number of free hydroxyl groups of the partial ester is equal to the number of carboxyl groups in the aliphatic hydroxy acid.  The fatty acid preferably contains 10-20 carbon atoms.  Typical partial esters of ethylene glycol are the mono-laurate, palmitate, margarate, stearate, oleate, and mono-esters of coconut, rapeseed, and castor oil fatty acids. Other partial esters are 1,2- or 1,3-propylene glycol mono-palmitate, stearate or oleate, diethylene glycol mono-esters of myristic, stearic, and oleic acids, glycerol discaproate, dicaprylate, dilaurate, dimyristate, dipalmitate, distearate and dioleate and similar mono-esters, monooleate of b ,b 1-dihydroxy diethyl sulphide, erythritol dipalmitate and distearate, pentaerythritol mono-oleate, dioleate, and dilaurate.  The hydroxy polycarboxylic acid may be a dicarboxylic acid of 4 carbon atoms such as citric, tartaric, malic, hydroxymethyl succinic, mucic, tartronic, methyl tartronic; a - and b -hydroxy glutaric.  The Specification as open to inspection under Sect. 91, comprises also acid esters made by varying the proportion of hydroxy polycarboxylic acid used, e.g. mono-(glycol monoleate)-malate. This subject-matter does not appear in the Specification as accepted.ALSO:Hydroxy esters are produced by esterifying the partial ester of a di-or poly-hydric alcohol with a fatty acid of at least 6 carbon atoms with an aliphatic hydroxy polycarboxylic acid containing not more than 3 carboxyl groups and not more than 6 carbon atoms and having at least 1 hydroxyl group not more than 2 carbon atoms removed from a carboxyl group, the proportion of reactants being such that the number of free hydroxyl groups of the partial ester is equal to the number of carboxyl groups in the aliphatic hydroxy acid.  The fatty acid preferably contains 10-20 carbon atoms. Typical partial esters of ethylene glycol are the monolaurate, palmitate, margarate, stearate, oleate, and mono-esters of coconut, rapeseed, and castor oil fatty acids.  Other partial esters are 1,2- or 1,3-propylene glycol monopalmitate, stearate or oleate, diethylene glycol mono-esters of myristic, stearic, and oleic acids, glycerol dicaproate, dicaprylate, dilaurate, dimyristate, dipalmitate, distearate and dioleate and similar mono-esters, mono-oleate of b ,b 1-dihydroxy diethyl sulphide, erythritol dipalmitate and distearate, pentaerythritol mono-oleate, dioleate, and dilaurate.  The hydroxy polycarboxylic acid may be a dicarboxylic acid of 4 carbon atoms such as citric, tartaric, maleic, hydroxymethyl succinic, mucic, tartronic, methyl tartronic, a - and b -hydroxy glutaric.  The products are emulsifying and dispersing agents, rust inhibitors, plasticizers for rubbers and additives for lubricating oils.  Mineral oils for cutting may contain 1 per cent of the esters and in general lubricants contain 1-10 per cent.  In examples: (1) ethylene glycol mono-oleate and malic acid are refluxed under reduced pressure with removal of water to give di-(ethylene glycol mono-oleate)-malate, which may be purified by washing; (2) di-(ethylene glycol mono-laurate)-malate is prepared similarly; (3) malic acid, glycol mono-stearate, toluene sulphonic acid, diethyl carbitol, and benzene, are refluxed and di-(ethylene glycol mono-stearate)-malate recovered; (4) tri-(ethylene glycol mono-oleate)-citrate is prepared in like manner; (5) glycol mono-caproate is prepared from caproic acid and glycol and converted to di-(glycol mono-caproate)-malate with malic acid; (6) di-(glycerol dioleate)-malate is similarly prepared from glycerol dioleate and malic acid.  The Specification as open to inspection under Sect. 91 comprises also the production of acid salts by varying the proportion of hydroxy polycarboxylic acid used, and a further example describes the preparation of mono-(glycol monooleate)-malate.  This subject-matter does not appear in the Specification as accepted.