Acrolein — Chambers's Encyclopaedia

Acrolein, $C_3H_3COH$ , is a colourless, limpid, strongly refracting liquid, lighter than water, and having its boiling-point at about $126^\circ F.$ ( $52.4^\circ C.$ ). It constitutes the acrid principle produced by the destructive distillation of fatty bodies, and is in part due to the decomposition of glycerine. It is best prepared by distilling a mixture of glycerine and anhydrous phosphoric acid, the object of the latter being to effect the removal of the element of four atoms of water from the glycerine, $C_3H_8O_3$ , which contains the elements of acrolein, $C_3H_3COH$ , + those of two molecules of water, $2H_2O$ . In its state of vapour, it is extremely irritating to the eyes, nostrils, and respiratory organs—a property to which it owes its name. The pungent smell given off by the smouldering wick of a candle just blown out is due to the presence of acrolein. When mixed with a solution of potash or soda, the irritating odour disappears, and is replaced by an odour of cinnamon, while a brown resinous substance is formed; and certain oxidising agents, as oxide of silver, convert it into acrylic acid, $C_2H_3COOH$ .