Patent GB-190311137-A (GB)
Title: Manufacture of Derivatives of Cyclohexane and Cyclohexene.
Inventor: IMRAY OLIVER
Filed: 1903-05-15
Granted: 1904-03-31
Abstract: 11,137. Imray, O., [Farbwerke vorm. Meister, Lucius, & Br³ning]. May 15. Cyclohexane and cyclohexene derivatives.-Relates to the manufacture of oxycyclohexane carboxylic acids and oxycyclohexane carbinols having the general formula by treating cyclohexenone carboxylic acids or their esters with reducing-agents. It also relates to the manufacture of derivatives thereof, and to the manufacture of cyclohexene carboxylic acids and their derivatives. The following examples are given :-(1) Ethyldimethylcyclohexenone carboxylate is dissolved in absolute alcohol, and sodium is gradually introduced. After heating, the mixture is diluted with water, and the alcohol distilled off. The upper oily layer, consisting chiefly of the oxycarbinol, is extracted with ether, while the lower aqueous layer, consisting of the sodium salt of the oxy acid, is repeatedly shaken up with ether to extract any further oxycarbinol. The two ethereal solutions are mixed together, dried, freed from ether by distillation, and purified, forming dimethyloxycyclohexane carbinol which is an exceedingly viscous syrup, and is a mixture of geometrically - isomeric bodies. The aqueous alkaline solution is acidified with dilute hydrochloric or sulphuric acid, filtered, shaken up with ether, dried, and the ether distilled off, leaving the dimethyloxycyclohexane carboxylic acid : as a thick yellowish oil. The esters are preferably obtained by the action of the corresponding alkyl iodide on the potassium salt. The ethyl ester is a thick colourless oil. By hydrolysing the pure ester with alcoholic alkali, a colourless viscous oil is obtained, which is a mixture of several geometrically-isomeric modifications of dimethyloxycyclohexane carboxylic acid. By boiling dimethyloxycyclohexane carbinol with acetic anhydride, an oily diacetyl compound, having a formula C13H22O4, is obtained. (2) Trimethyloxycyclohexane carboxylic acid and trimethyloxycyclohexane carbinol are obtained by reducing an ester of trimethyl cyclohexenone carboxylic acid, such as that obtained by condensing ethylic sodioacetoacetate with ethyl isopropylidene acetoacetate as described in Specification No. 11,138, A.D. 1903. The reaction is similar to that in the Example 1. After driving off the alcohol, the upper oily layer is boiled for a day at least with strong alcoholic potash in a vessel with a reflux condenser, or in a closed vessel. After diluting with water and expelling the alcohol with steam, the carbinols remain as a yellow thick layer of oil. The crude trimethyloxycyclohexane carboxylic acid, which occurs in several stereo - isomeric forms, is a colourless exceedingly - viscous syrup. The ethyl ester, C9H16(OH)COOC2H5 is a viscous colourless oil, which is smoothly oxidized by Beckmann's solution to etbyltrimethylketocyclohexane carboxylate, which is a thin colourless oil. Besides trimethyloxycyclohexane carboxylic acid, a small quantity of trimethylcyclohexene carboxylic acid is obtained, of which the ethyl ester is a thin liquid of pleasant odour. The trimethyloxycyclohexane carbinol is an exceedingly-viscous syrup, consisting of a mixture of stereo-isomeric modifications. One modification of the glycol may be crystallized in a pure state from benzene. Small quantities of trimethylcyclohexene carbinol and trimethylcyclohexane carbinol are also obtained besides the oxycarbinol. Trimethal oxycyclohexane carboxylic acid is also obtained by reducing trimethylcyclohexenone carboxylic acid with sodium or sodium amalgam. (3) Ethyltrimethyloxycyclobexane carboxylic acid is obtained by dissolving ethyltrimethylcyclohexenone carboxylate in caustic soda in the presence of alcohol, and electrolysing with a diaphragm, carbonic acid being introduced. Reduction occurs. The alcohol is distilled off, the aqueous liquid shaken up with ether, the ether expelled, and the oil boiled with strong alcoholic potash. The alcohol and isophorone are then driven off by steam, acid is added, and the acid obtained by shaking up with ether. Similarly, trimethyloxycyclohexane carboxylic acid is obtained from trimethyloxycyclohexenone carboxylic acid. (4) Ethyltrimethyloxycyclohexane carboxylate is obtained by reducing the corresponding hexenone compound with zinc, iron, magnesium, or the like in a solution of hydrochloric, hydrobromic, or hydriodic acid. (5) Dimethycyclohexene carboxylic acid is obtained by boiling ethyldimethyloxycyclohexane carboxylate in a vacuum with potassium bisulphate, or distilling it with phosphoric anhydride, and hydrolysing the ester obtained. (6) Trimethylcyclohexene carboxylic acid is obtained from ethyltrimethyloxycyclohexane carboxylate by gradually adding a mixture of phosphorus trichloride, or phosphorus oxychloride, and quinoline. The phosphorous anhydride ester remains dissolved in the ether. It is removed, purified, and dried, and the ether is distilled off. The ester is then decomposed by heat, the ethyltrimethylcyclohexene carboxylate passing over. The acid is obtained from the distillate by hydrolysis. Or the ethyltrimethylcyclohexene carboxylate may be distilled in a vacuum with phosphorus pentoxide. The trimethylcyclohexene carboxylic acid is also obtained by distilling in a vacuum trimethyloxycyclohexane carboxylic acid with finelyground potassium bisulphate, separating the products, and purifying by distilling in a vacuum the desired product. Another method consists in acting on the oxy compound of ethyltrimethylcyclohexane carboxylate with a halogen hydride, then boiling the product with alcoholic potash, and afterwards expelling the alcohol. The acid is subsequently precipitated by a mineral acid, and is purified, after drying, by distillation in a vacuum.