Its formation from two molecules of CH2O would then take place according to the equation: If the constitution given for the aldehyde C1H2O be correct, the unsaturated alcohol C1H2O, which is formed from it by the action of nascent hydrogen, may be represented thus CH3.CH2.CH2.CH2. CH2. CH2.CH CH3.CH2.CH2.CH2.CH2.C.CH2OH, and the saturated alcohol, being formed by the action of nascent hydrogen on the unsaturated alcohol, will therefore have the following constitution: CH3.CH.CH2.CH2. CH2. CH2.CH2 CH3.CH2.CH2.CH2.CH2.CH.CH2OH, and is therefore B-heptyl-heptyl alcohol, or heptyl-pentyl-ethyl alcohol. And finally the acid C1H2O2 will have the constitution CH3.CH2.CH2. CH2. CH2. CH2. CH н. С.соон, CH3.CH2. CH2.CH2. CH2.C.COOH, and is therefore hexyl-pentyl-acrylic acid. IX.-Condensation-products of Enanthaldehyde (Part II). By W. H. PERKIN, JUN., Ph.D.. Action of Nascent Hydrogen on Enanthaldehyde. In the preparation of heptyl alcohol by the action of nascent hydrogen on œnanthaldehyde, there is always a considerable quantity of a highboiling bye-product formed, which often amounts to 20 per cent. of the enanthaldehyde used. This remains in the retort, on distilling off the heptyl alcohol, as a thick brown oil, which, however, does not seem to have been investigated. As it was probable that these oils were simply condensation-products, produced by the dehydrating action of the agents used, and possibly acted on by the nascent hydrogen; it was thought that they might yield interesting results upon examination. The inquiry was divided into two parts: (1), action of nascent hydrogen on enanthaldehyde in acid solution ; (2), in ethereal solution. (1.) Action of Nascent Hydrogen on Enanthaldehyde in Acetic Acid Solution. The operations were conducted in the same manner as described in Part I, in the section on the action of nascent hydrogen in acid solution on the aldehyde CH2O. It is practically the same as that employed by C. F. Cross (Jour. Chem. Soc., 32, 123) for the preparation of heptyl alcohol. 200 grams of cenanthaldehyde were used in each operation, and about twice as much sodium amalgam as theoretically required for the formation of heptyl alcohol. At the end of the reaction water was added, and the oil, after being washed, was boiled with a dilute solution of potash, in order to decompose acetates, which are always formed. It was then washed, dried, and distilled under reduced pressure (350 mm.), until the temperature reached 300°. The residue was not examined. The distillate was fractioned under ordinary pressure. The principal quantity, consisting of heptyl alcohol and a small quantity of unchanged œnanthaldehyde, came over below 200°; the thermometer then rose rapidly to 240°, between which temperature and 300° a large amount of product distilled over. This last quantity was repeatedly rectified, when three fractions were obtained, boiling between 270-275°, 275-280°, and 280-283°, all of about the same size. The analyses of these gave numbers which always came between those calculated for the alde VOL. XLIII. F 26 hyde C1H2O, and the alcohol C1H2O, so that it appeared very probable that both were present. In order to separate them the fractions between 265-285° were heated in sealed tubes with excess of acetic anhydride at 180-200° for four days, and then distilled. After the acetic acid and excess of anhydride had passed over, a considerable quantity of oil was obtained boiling between 270-300°. There was, however, a dark brown residue left, which would seem to show that, as was anticipated, some aldehyde, such as CH2O, was previously present, and had been condensed by the action of the acetic anhydride. The oil distilling between 270-300° was then repeatedly fractioned, and at last gave a product which boiled pretty steadily between 280— 285°. It was a colourless, highly refracting oil, possessing an agreeable odour. The analysis gave the following numbers: I. 0.1860 gram substance gave 0.1992 gram CO2. II. 0.2167 gram substance OH, and 0.5170 gram 75.89 per cent. This was therefore the acetate derived from the alcohol C1HO. As this substance, from its composition, should be an unsaturated body, it was dissolved in carbon disulphide, cooled down to -10°, and titrated with bromine. The colour of the bromine disappeared instantaneously without evolution of hydrobromic acid. A quantitative experiment gave the following numbers: 2-2355 grams substance took up, without evolution of hydrobromic acid, 1.3477 gram bromine = 60.3 per cent. Calculated for C16H30O2 + Br2 = 62.9 per cent. Attempts were made to isolate the bromine addition-product, but the body decomposes on distilling off the carbon disulphide, giving off hydrobromic acid. This acetate was saponified by boiling with alcoholic potash. On distilling off the alcohol and adding water to the residue, the alcohol This was taken up with ether, and the After a few fractional distillations the C1H2O separates as an oil. 28 ethereal solution distilled. principal quantity came over as a colourless oil boiling at 280–283°. Analysis gave the following result: 0-1494 gram substance gave 0·1777 OH, and 0·4340 CO2. There can be no doubt that this alcohol and the acetate from which it was separated are the same bodies as those described in Part I, p. 55, as the properties of the two so closely agree. The formation of this alcohol from œnanthaldehyde is probably due to the dehydrating action of the glacial acetic acid and sodium acetate, formed in the reaction, first producing the aldehyde CH2O, a part of which is then acted on by nascent hydrogen, yielding this product. It is practically impossible to separate the aldehyde CH2O from the alcohol CH2O by fractional distillation, but the treatment with acetic anhydride forms an easy way of separating them, as shown in Part I. The products of the action of nascent hydrogen in acid solution, as far as they have been examined, are therefore, heptyl alcohol, probably the aldehyde Ci.H2O, and the alcohol C14H2O. (2.) Action of Nascent Hydrogen on Enanthaldehyde in Ethereal Solution. This operation was conducted in the same way as that described in Part I, p. 54, where the treatment of an ethereal solution of the aldehyde, CH2O, is described.. 450 grams of oenanthaldehyde dissolved in about 1 to 2 litres of ether, and from 200 to 210 grams of sodium, were used in each experiment, which required from four to five days for completion. The ethereal was separated from the aqueous solution, well washed, first with dilute hydrochloric acid and then with water, and dried over calcium chloride. The examination of the aqueous solution showed that it contained an oily acid boiling between 221-225°; it gave the following numbers on analysis: 0.2714 gram substance gave 0.2631 gram OH, and 0·6400 gram CO2. Found. C...... 64.31 per cent. It was therefore heptoic acid. Calculated for CH13COOH. 64.61 per cent. The ethereal solution, containing the neutral oils, was next examined. After the ether had been distilled off, the oil was fractioned in a stream of carbonic anhydride. It began to boil at 150°, between which temperature and 200° a considerable quantity distilled over, consisting of a mixture of heptyl alcohol and unchanged oenanthaldehyde. The thermometer then rose rapidly to 250°, a large quantity coming over between 250-300°. The residue was reserved for distillation in vacuo, and is referred to further on. The portion boiling between 250-300° was several times carefully fractioned in a stream of carbonic anhydride, as the oils oxidise in the air. It was found that when cooled down to 0° all the fractions from 255-280° deposited crystals, some becoming almost solid. In order to obtain this solid product in a pure state, the various fractions were cooled down to -20° in a mixture of ice and hydrochloric acid, and the oil then filtered off from the crystals as quickly as possible, by means of a vacuum pump. They were then quickly pressed between filter-paper at as low a temperature as possible, and further purified by crystallisation from ether, in which they are very soluble; on allowing the solution to evaporate spontaneously, large transparent crystals, with a beautiful lustre, were deposited. These were filtered off from the ethereal solution, and placed over sulphuric acid in an atmosphere of CO, for some time. The following analyses were made from several preparations : I. 0-1693 gram substance gave 0·1977 OH, and 0.4939 CO2. |