Patent GB-664992-A (GB)
Title: Hydroxy ester derivatives of propylene oxide
IPC: C08G65/28
Filed: 1948-09-23
Abstract: Hydroxy ester derivatives of propylene oxide suitable for use as lubricants are obtained by reacting from 10 to 48 molecular proportions of propylene oxide with one molecular proportion of an aliphatic ester of a hydroxy aliphatic carboxylic acid containing from 1 to 3 carboxyl groups and one or more hydroxyl groups.  The terminal hydroxyl group of the product may be etherified or esterified.  It is preferred to use from 10 to 30 and especially from 14 to 22 molecular proportions of the propylene oxide.  The p hydrocarbon chain of the hydroxy acids may be saturated or unsaturated and the acids specified are glycollic acid, hydracrylic acid, hydroxybutyric acid, hydroxy caproic acid, lactic acid, malic acid, citric acid, hydroxy-stearic acid and ricinoleic acid.  The esterifying radical may be a saturated or unsaturated hydrocarbon group and may contain hydroxyl groups as in the glyceryl radical. Other specified radicals are ethyl, propyl, butyl, amyl, octyl, decyl, dodecyl, stearyl, oleyl and long-chain radicals derived from cracked paraffinic waxes.  The preferred hydroxy acid esters are those having 2 to 20 carbon atoms in the acid radical and 1 to 20 carbon atoms in the ester group and the ester should preferably contain 1 to 4 hydroxyl groups per molecule.  The reaction may be conducted at temperatures down to -10 DEG  C. and metal halide catalysts such as boron fluoride and stannic chloride are generally required.  In examples: (1) ethyl lactate (1 molecular proportion) is treated with propylene oxide (14 molecular proportions) in the presence of anhydrous SnCl4 in chloroform at 30 DEG  C.; (2) di-n-butyl malate (1 molecular proportion) is reacted with propylene oxide 14 molecular proportions in the presence of BF3 at 35-45 DEG C.; (3) triethyl citrate and propylene oxide are reacted as in (2) except that the molecular proportion of propylene oxide to ester is 16 : 1; (4) castor oil (one molecular proportion) is reacted with 48 molecular proportions of propylene oxide in the presence of BF3 as in (2).  The properties of the products as lubricants are given in each case.  Specifications 312,523, [Class 2 (iii)], and 443,631 are referred to.  The Specification as open to inspection under Sect. 91 refers to the use of any alkylene oxide in any molecular proportion and states that a hydroxy aliphatic carboxylic acid as well as the ester thereof may be treated.  Ethylene oxide, isopropyl ethylene oxide, isobutylene oxide and butadiene monoxide are additional alkylene oxides, specified.  This subject-matter does not appear in the Specification as accepted.ALSO:Hydroxy ester derivatives of propylene oxide suitable for use as lubricants are obtained by reacting from 10 to 48 molecular proportions of propylene oxide with one molecular proportion of an aliphatic ester of a hydroxy aliphatic carboxylic acid containing from 1 to 3 carboxyl groups and one or more hydroxyl groups.  The terminal hydroxyl group of the product may be etherified or esterified.  It is preferred to use from 10 to 30 and especially from 14 to 22 molecular proportions of the propylene oxide.  The hydrocarbon chain of the hydroxy acids may be saturated or unsaturated and the acids specified are glycollic acid, hydracrylic acid, hydroxybutyric acid, hydroxy caproic acid, lactic acid, malic acid, citric acid, hydroxystearic acid and ricinoleic acid.  The esterifying radical may be a saturated or unsaturated hydrocarbon group and may contain hydroxyl groups as in the glyceryl radical.  Other specified radicals are ethyl, propyl, butyl, amyl, octyl, decyl, dodecyl, stearyl, oleyl and longchain radicals derived from cracked paraffinic waxes.  The preferred hydroxy acid esters are those having 2 to 20 carbon atoms in the acid radical and 1 to 20 carbon atoms in the ester group and the ester should preferably contain 1 to 4 hydroxyl groups per molecule.  The reaction may be conducted at temperatures down to - 10 DEG  C. and metal halide catalysts such as boron fluoride and stannic chloride are generally required.  In examples: (1) ethyl lactate (1 molecular proportion) is treated with propylene oxide (14 molecular proportions) in the presence of anhydrous SnCl4 in chloroform at 30 DEG  C.; (2) di-n-butyl malate (1 molecular proportion) is reacted with propylene oxide (14 molecular proportions) in the presence of BF3 at 35-45 DEG C.; (3) triethyl citrate and propylene oxide are reacted as in (2) except that the molecular proportion of propylene oxide to ester is 16 : 1; (4) castor oil (1 molecular proportion) is reacted with 48 molecular proportions of propylene oxide in the presence of BF3 as in (2).  The properties of the products as lubricants are given in each case.  Specifications 312,523, [Class 2 (iii) and 443,631 are referred to.  The Specification as open to inspection under Sect. 91 refers to the use of any alkylene oxide in any molecular proportion and states that a hydroxy aliphatic carboxylic acid as well as the ester thereof may be treated.  Ethylene oxide, isopropyl ethylene oxide, isobutylene oxide and butadiene monoxide are additional alkylene oxides specified.  This subject-matter does not appear in the Specification as accepted.