TOLUALDEHYDES

Chemical properties

Colorless liquid. Slightly soluble inwater; soluble in alcohol and ether. There are also oand misomers. Combustible.

Chemical properties

Tolualdehydes, mixed o-, m-, p-, have a sweet and herbaceous odor reminiscent of bitter almond.

Occurrence

Reported found in roasted nuts, tomato, cooked beef, beef fat, cider, coffee, tea and elderberry juice.

The Uses of TOLUALDEHYDES

Perfumes, pharmaceutical and dyestuff intermediate, flavoring agent.

Preparation

By oxidation of o-, m-, or p-xylene (chemical or electrolytical oxidation).

Taste threshold values

Taste characteristics at 15 ppm: cherry pit, coumarin, almond, sweet, with a slight powdery hay and vanillalike nuance.

Metabolism

Aromatic aldehydes are oxidized in vivo almost entirely to the corresponding acid. Thus, in rabbits, p-tolualdehyde is converted to p-toluic acid which has been detected in the urine as the ester glucuronide (Williams, 1959). p-Tolualdehyde was oxidized to p-toluic acid by resting cells of Pseudomonas aeruginosa (Omori & Yamada, 1970). Perillaldehyde dehydrogenase, isolated from a soil pseudomonad, catalysed the oxidation of m- and p-tolualdehyde but not of o-tolualdehyde (Ballal, Bhattacharyya & Rangachari, 1967). The reduction of p-tolualdehyde by NADH was catalysed by horse-liver alcohol dehydrogenase (Blomquist, 1966) and by yeast alcohol dehydrogenase at pH 8.5-9.5 (Klinman, 1975). A non-specific NADPH-linked aldehyde reductase isolated from various areas of bovine brain also catalysed the reduction of p-tolualdehyde (Tabakoff & Erwin, 1970).