GB936808A - Improvements in or relating to the production of epoxy alkyl esters - Google Patents

Abstract

Alkyd resins are made by reacting an epoxy alkyl or epoxycycloalkyl ester of an alkane monocarboxylic acid, in which acid the carbon atom to which the carboxylic acid is directly attached, is a tertiary or quaternary carbon atom (for preparation of esters see Group IV(b)), with polybasic carboxylic acids or anhydrides thereof. Suitable acids are dibasic acids from malonic to sebacic, maleic, fumaric, phthalic, isophthalic, terephthalic, tetrahydroand hexahydro-phthalic acids, diglycolic acid and dimerized fatty acids of drying oils. Suitable anhydrides include Diels-Alder adducts of maleic anhydride with dienes such as terpenes and cyclopentadiene. Catalysts such as Lewis bases, hydroxy compounds, amines, acid amides, mercaptans, dialkyl sulphides and sulphoxides may be used, generally in a quantity of 0,1 to 10% by weight based on the reaction mixture. The alkyd resins may be worked up to paints, lacquers and varnishes; pigments, diluents, phenol formaldehyde, urea formaldehyde or melamine resins being added, if desired. In an example, an alkyd resin is made by reacting with glycerol and phthalic acid anhydride the glycidyl ester of an x-alkylalkane monocarboxylic acid whose hydrocarbon chain contains 9 to 11 carbon atoms (said acid having been made by reacting C8 to C10 alkenes with carbon monoxide and water). Specification 844,312 is referred to.ALSO:The invention comprises an epoxyalkyl or epoxycycloalkyl (other than 2:3-epoxycyclopentyl) ester of an alkane monocarboxylic acid, in which acid the carbon atom to which the carboxylic acid group is directly attached, is a tertiary or quaternary carbon atom, in particular an ester of the formula:- <FORM:0936808/IV(a)/1> in which R1 and R2 represent similar or dissimilar alkyl groups and R3, R4, R5, R6 R7 and R8 each represent hydrogen or a hydrocarbon radical, e.g. an alkyl group. The radicals R4, R5, R6, R7 and R8 may also be bound in pairs by divalent hydrocarbon radicals as with R4 and R7 in epoxycyclohexyl esters. Preferred epoxyalkyl esters are those in which the acid has more than 8 carbon atoms and is obtained by reacting carbon monoxide with water and at least one mono-olefine having from 8 to 18 carbon atoms in the molecule. The epoxyalkyl esters may be made by reacting an alkane monocarboxylic acid as defined above, preferably an a -mono-alkylalkane monocarboxylic acid or a ,a -dialkylalkane monocarboxylic acid, with an epoxy halogen alkane, an epoxyhydroxy alkane or a halohydrin. Alkali metal salts or quaternary ammonium salts of the acids may also be used preferably as an aqueous solution, emulsion or suspension. The reaction may take place in the presence of an esterification catalyst, such as a tertiary amine or quaternary ammonium salt. A small amount of alkali may be added. Solvents such as ketones may be used. The temperature is generally between 50 and 180 DEG C. The epoxyalkyl esters may also be made by epoxidising an ester of an a -alkylalkane monocarboxylic acid and an ethylenically unsaturated alcohol or by epoxidising an ethylenically unsaturated alcohol or derivative which is then converted to the desired ester. The epoxidation is preferably effected with a peracid, e.g. peracetic, performic, perpropionic, perbutyric, pervaleric, permonochloro-acetic, pertrifluoroacetic, percrotonic, diperoxalic, perbenzoic, monoperphthalic and percamphonic acid. Aliphatic hydrocarbon halohydrocarbon ether solvents may be used and temperatures are generally in the range -20 DEG to 100 DEG C. A buffer may be used with the stronger acids, e.g. sodium acetate, sodium carbonate, disodium phosphate, an alkali metal salt of an ion exchanger or alumina. The peracid may be formed in situ from a carboxylic acid or anhydride and hydrogen peroxide, or by oxidation of an aldehyde. Hydroperoxides such as t-butylhydroperoxide may also be used to effect epoxidation. The reaction is catalysed by alkaline substances. The epoxidation may also be effected with hydrogen peroxide at pH of 7 to 10, or with a solution of chromic acid anhydride in concentrated acetic acid. Epoxidation may also take place by reaction of the unsaturated compound with a hypohalous acid followed by splitting of hydrogen halide with a base. The epoxyalkyl esters may be purified by washing with a mixture of water and a water miscible polar liquid such as methanol ethanol or an aliphatic ketone, preferably after being dissolved in an aromatic hydrocarbon, such as xylene. The a -alkylalkane monocarboxylic acids are preferably obtained by reacting carbon monoxide and water with olefins having 3 or more carbons per molecule under the influence of acid catalysts such as phosphoric acid, sulphuric acid and complexes of phosphonic acid with boron fluorides. Detailed examples are given. Specification 844,312 is referred to.