Benzaldehyde

Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful.Amygdalinbenzaldehyde2 × glucose Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful. It is a colorless liquid with a characteristic almond-like odor. The primary component of bitter almond oil, benzaldehyde can be extracted from a number of other natural sources. Synthetic benzaldehyde is the flavoring agent in imitation almond extract, which is used to flavor cakes and other baked goods. Benzaldehyde was first extracted from bitter almonds in 1803 by the French pharmacist Martrès. In 1832, German chemists Friedrich Wöhler and Justus von Liebig first synthesized benzaldehyde. As of 1999, 7000 tonnes of synthetic and 100 tonnes of natural benzaldehyde were produced annually. Liquid phase chlorination and oxidation of toluene are the main routes. Numerous other methods have been developed, such as the partial oxidation of benzyl alcohol, alkali hydrolysis of benzal chloride, and the carbonylation of benzene. A significant quantity of natural benzaldehyde is produced from cinnamaldehyde obtained from cassia oil by the retro-aldol reaction: the cinnamaldehyde is heated in an aqueous/alcoholic solution between 90 °C and 150 °C with a base (most commonly sodium carbonate or bicarbonate) for 5 to 80 hours, followed by distillation of the formed benzaldehyde. This reaction also yields acetaldehyde. The natural status of benzaldehyde obtained in this way is controversial. 'Site-specific nuclear magnetic resonance spectroscopy', which evaluates 1H/2H isotope ratios, has been used to differentiate between naturally occurring and synthetic benzaldehyde. Benzaldehyde and similar chemicals occur naturally in many foods. Most of the benzaldehyde that people eat is from natural plant foods, such as almonds. Almonds, apricots, apples, and cherry kernels contain significant amounts of amygdalin. This glycoside breaks up under enzyme catalysis into benzaldehyde, hydrogen cyanide and two equivalents of glucose. Benzaldehyde contributes to the scent of oyster mushrooms (Pleurotus ostreatus).