The simplest member of the series is acrolein, C 3 H 4 0 or CH 2: CHï¿½CHO, which can be prepared by the oxidation of allyl alcohol, or by the abstraction of the elements of water from glycerin by heating it with anhydrous potassium bisulphate.
By passing acrolein vapour into ammonia, acrolein ammonia, C 6 H 9 NO, is obtained.
Cinnamic aldehyde ((3-phenyl acrolein), C6H5ï¿½CH: CHï¿½CHO, an unsaturated aromatic aldehyde, is the chief constituent of cinnamon oil.
Scholtz (Ber., 1894, 2 7, p. 2 95 8) from piperonyl acrolein (the condensation product of piperonal and acetaldehyde) and acetic acid.
Fischer showed that methose was identical with the a-acrose obtained by himself and Tafel in 1887 by decomposing acrolein dibromide with baryta, and subsequently prepared by oxidizing glycerin with bromine in alkaline solution, and treating the product with dilute alkali at o°.
Glyceric aldehyde, CH 2 OH CH(OH) CHO, was obtained pure by Wohlon oxidizing acrolein acetal, CH 2 CH(OC 2 H 5) 21 and hydrolysing.
By boiling this varnish with dilute nitric acid vapours of acrolein are given off, and the substance gradually becomes a solid non-adhesive mass the same as the ultimate oxidation product of both raw and boiled oil.
Fischer has used it as a condensing agent in the preparation of aand 0-acrose from acrolein dibromide.
One, and its mechanism may probably be explained as follows: The glycerin is first converted into acrolein, which combines with the aniline to form acrolein-aniline, and this product is then oxidized by the nitrobenzene: C3H803-*C,H40 (C6H5NH2)-sC6H5N: CH CH: CH2-*C9H7N.
Iodide by the action of moist silver oxide; by the reduction of acrolein; or by heating glycerin with oxalic acid and a little ammonium chloride to 260° C. In this last reaction glycerol monoformin is produced as an intermediate product, but is decomposed as the temperature rises: C3H5(OH)3+H2C204 = C3H5(OH),.0.CHO+C02+H20 glycerol monoformin C 3 H 5 (OH) 2.0.
Oxidation by strong oxidizing agents converts it successively into its aldehyde, acrolein, and into acrylic acid.
Above 300° C. all oils and fats are decomposed; this is evidenced by the evolution of acrolein, which possesses the wellknown pungent odour of burning fat.