II. New volatile organic acids, from the berry of the mountain ash

• Published in: Proceedings of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1859
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1098/rspl.1857.0137; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1857.0137

Whoever has been engaged in the preparation of malic acid from the juice of the unripe berries of the Mountain Ash ( Sorbus Aucuparia ), cannot have failed to perceive the peculiar powerful odour evolved during the evaporation of the liquid partially saturated with lime. The body to which this odour belongs was hitherto un­known, and only lately, my friend and former pupil, Dr. George Merck of Darmstadt, when preparing malic acid on a large scale, conceived the happy idea of evaporating the liquid in a distilling apparatus. He thus obtained an acid distillate, from which he suc­ceeded in separating an oily body possessed of acid properties. To the kindness of Dr. Merck I am indebted for an appreciable quan­tity of this remarkable body, which has enabled me to examine its properties and establish its composition. The preparation of the oil from the aqueous acid obtained by distilling the mother liquor of the bimalate of calcium, presents no difficulty. The liquid is saturated with soda, evaporated and mixed with dilute sulphuric acid, when the oil rises as a brown layer to the surface of the liquid. It is separated by ether, and after the volati­lization of the latter, submitted to distillation. The first portions of the distillate contain appreciable quantities of water; the thermo­meter, however, rapidly rises above 200°C. What now distils is a perfectly pure compound, which, on redistillation, exhibits a constant boiling point at 220°C. Freshly distilled, the oil is colourless, but it soon acquires a yellowish tint. It has a peculiar aromatic odour, not disagreeable when dilute, but rather offensive when con­centrated. The specific gravity is 1.0681. It is somewhat soluble in water, very soluble in alcohol and ether; these solutions are di­stinctly acid. The oil dissolves in potassa and ammonia, also in the carbonated alkalis, without, however, expelling their carbonic acid. Mineral acids separate it again from these compounds