Patent GB-573318-A (GB)
Title: Improvements in and relating to the production of ether esters
Filed: 1943-10-18
Abstract: 1-Acyloxyethyl ethers of alpha-hydroxy carboxylic acids are prepared by reacting a vinyl ester of an aliphatic carboxylic acid which is free from aliphatic unsaturation and from active hydrogen as determined by the Zerewitinoff method, with an alkyl ester of a saturated alpha-hydroxy aliphatic carboxylic acid under substantially anhydrous conditions at elevated temperature and in the presence of a catalyst containing mercury.  The products have the general formula <FORM:0573318/IV/1> in which R is hydrogen or an aliphatic radical free from active hydrogen and ethylenic and acetylenic unsaturation and is preferably hydrocarbon, R1 is hydrogen or an aliphatic radical free from ethylenic and acetylenic unsaturation and is preferably a saturated hydrocarbon radical or hydrogen and R2 is an alkyl radical. In hydrolysis with dilute aqueous mineral acids, they yield acetaldehyde, an alkanol R2OH, an acid R.CO.OH and an alpha - hydroxy acid R1.CHOH.CO.OH. Specified starting materials include methyl hydroxyacetate, isobutyl lactate, cyclohexyl alpha-hydroxy butyrate, dodecyl alpha-hydroxy valerate, propyl tartrate, butyl citrate, t-butyl mucate and methyl cyclohexyl hydroxyacetate.  The vinyl esters specified are: vinyl formate, acetate, propionate, butyrate, pivalate, laurate, stearate, chloracetate, methoxy acetate, adipate and sebacate.  The preferred starting materials are the alkyl esters of hydroxy fatty acids and the vinyl esters of saturated fatty acids. In the case of aliphatic polycarboxylic acids, the neutral esters are preferred.  The catalysts employed are those which catalyse the formation of ethylidene derivatives in the reaction of hydroxy compounds with acetylene and include mercuric phosphate, mercuric acetate, mercuric sulphate, mixtures of mercuric oxide with boron trifluoride in the form of complexes of the latter with, for example, ether, methanol, acetic acid, or water, and mixtures of mercuric oxide with silicon tetrafluoride and water or methanol complexes. The reaction may be carried out at a temperature between 30 DEG  C. to 150 DEG  C., preferably 70 DEG  C. to 100 DEG  C.  Inert solvents such as benzene, 1,4-dioxane, ethyl acetate, toluene and diethyl ether may be employed.  With a low boiling reactant or solvent superatmospheric pressure may be employed.  In an example, methyl hydroxy acetate is reacted with vinyl acetate in the presence of anhydrous mercuric phosphate to give the 1-acetoxyethyl ether of methyl hydroxy acetate which on hydrolysis yields acetaldehyde, methanol, hydroxy acetic acid and acetic acid.  According to the Provisional Specification, the products may have the above general formula, R representing hydrogen or an organic radical free from active hydrogen and ethylenic and acetylenic unsaturation and R1 representing hydrogen or an organic radical free from ethylenic and acetylenic unsaturation and includes the use of the following additional starting materials: furfuryl alpha-hydroxy isobutyrate, ethyl mandelate, isopropyl benzilate, ethyl furfuryl hydroxy acetate, methyl p-chloromandelate, and the following vinyl esters: vinyl benzoate, naphthoate and pyridinecarboxylate.