GB537980A - - Google Patents

Abstract

537,980. Glycollic acid derivatives. DU PONT DE NEMOURS, & CO., E. 1. Jan. 11, 1940, No. 662. Convention date, Jan. 11, 1939. [Class 2 (iii)] Glycollic acid derivatives in which the hydrogen of the hydroxyl group is replaced by an aliphatic radical are made by subjecting a methylene glycol ether to the action of carbon monoxide, if necessary at a raised temperature and pressure, and preferably in presence of an acid catalyst. As parent materials, the dimethyl, methyl ethyl, diethyl, dipropyl, di-isopropyl, dibutyl, di-isobutyl, diamyl, dioctyl, diallyl, and dibutene ethers are specified. As catalysts, inorganic and organic acids and acid salts, and non-metal halides, e.g. boron chloride and fluoride, are specified. When boron fluoride is used, it may first be combined with the methylene glycol ether and the resulting complex reacted with carbon monoxide. Complexes of boron trifluoride with water or organic compounds, e.g. dimethyl ether, methanol, methylmethoxy acetate and glycollide, may also be used as catalysts. The methylene glycol ether and catalyst may be passed through a reaction zone in co-current or counter-current to a stream of carbon monoxide. The preparation of methylmethoxy, ethylethoxy, and isobutylisobutoxy acetates is described in examples. The products may be hydrolysed to the free acids simultaneously with or subsequently to the reaction. The Specification as open to inspection under Sect. 91 comprises also the treatment of aryl, aralkyl, acyl, heterocyclic or alicyclic ethers of methylene glycol, and specifies the dibenzyl, diphenyl ethyl, and bis(ethoxymethyl) ethers and formaldehyde dibutene acetal. Cyclic glycol formals, decamethylene glycol formal, cyclohexyl formal, symmetrical and unsymmetrical acyl ethers of methylene glycol, e.g. the methylacetyl, diacetyl, and ethylpropionylethers, are also specified. This subject-matter does not appear in the Specification as accepted.