Patent GB-396761-A (GB)
Title: Manufacture of condensation products
IPC: C07D319/12
Filed: 1932-01-05
Abstract: Cyclic ethers are produced by condensing a partial organic ester or ether of glycerin or other polyhydric alcohol containing at least two free hydroxy groups (but in which the ester or ether groupings do not contain hydroxy groups) with itself or with a glycol or polyhydric alcohol or aliphatic aldehyde or, according to the Provisional Specification, with a such as acetone. Monoacetin, monolaurin, monoolein, monopalmitin, monostearin, and erythrite diacetate are suitable esters, and ethylene, propylene and butylene glycols, diethylene glycol, formaldehyde, acetaldehyde and aerolein are suitable second components. Mixtures of partially esterified or etherified polyhydric alcohols may be employed whether or not a glycol or aldehyde is used; for example erythrite diacetate may be condensed with monoacetin, or a mixture of ester and ether may be used such as glycerin monoethyl or monomethyl ether with monoacetin. The condensation may be effected with acid dehydrating agents such as sulphuric, hydrochloric, or phosphoric acid, zinc chloride, sodium bisulphate, or benzene sulphonic acid; or chlorides such as calcium, magnesium and sodium chlorides, or calcium carbonate and alumina, or mixtures of these substances.  The condensation may be effected under such conditions that hydrolysis of the ester or ether group takes place so as to produce a hydroxycyclic ether as referred to in Specifications 392,160, 392,186, and 392,191 or so that a cyclic ether similar to diglycerin triether is produced as referred to in Specification 392,186.  The reaction may be effected so that the product remains in the reaction mixture until the end of the reaction, or the product may be continuously removed during the reaction.  A diluent such as benzene, toluene or other hydrocarbon may be employed, and the conditions may be such that the water is removed as an azeotropic mixture.  The distillate or, where distillation is not employed, the reaction mixture, may be purified in any suitable way, preferably after removing the catalyst. Aldehydic bye-products may be removed from the reaction-mixture by means of bisulphites, and water may be removed as an azeotropic mixture by means of a hydrocarbon or methylene chloride.  Where the condensation has been effected so that hydrolysis of the ester or ether groups is not effected, and it is desired to obtain a hydroxy-ether, hydrolysis may be effected afterwards, by means of acid or alkaline agents.  In examples (1) Equimolecular proportions of monoacetin and glycerin monomethyl ether are heated at 200 DEG  C. with 5 per cent of calcium chloride and 10 per cent of calcium carbonate; the dehydrating agent is separated, and the mixture is then fractionated or extracted with a solvent such as ether, the extract being then fractionated to obtain the product, acetylcarbinyl (methoxy methyl) dioxane.  (2) An aqueous solution of erythrite diacetate and acetaldehyde containing about 1\ba1/2\be mols. aldehyde to 1 mol. acetate is saturated with hydrochloric acid and kept at a moderate temperature for several hours; it is then saturated with potassium carbonate, and the product, di (acetyl carbinyl) dioxide, is extracted with ether and separated by distillation. The cyclic ethers, whether containing external ester or ether groups or not, are solvents and softening agents for cellulose esters and ethers and other lacquer bases and may be used for the treatment of formed articles of cellulose esters and ethers, and in sizes for the lubrication of yarns.  The cyclic ethers containing ester groups of higher fatty acids and naphthenic acids are particularly suitable for this purpose; they may be made from the partially esterified polyhydric alcohol or by esterifying the hydroxy cyclic esters, if necessary after removing existing ester groups.