As its chemical formula C6H5CHO implies, benzaldehyde is a colorless organic compound that comprises a benzene ring along with a formyl substituent. Benzaldehyde is considered to be the simplest fragrant aldehyde and extensively used for various industrial purposes.
The typical benzaldehyde aroma is similar to that of almond. In fact, this liquid organic compound is the main constituent of bitter almond oil or apricot oil and it is derived from various natural sources. Often synthetically obtained benzaldehyde is used as a flavoring agent, imitating the effects of almond extract. This synthetic product is used for adding essence to cakes as well as several other baked items.
In 1803, renowned French pharmacist Martrès was the first to extract benzaldehyde from bitter almonds. Benzaldehyde was synthesized for the first time in 1832 by two German chemists named Friedrich Wöhler and Justus von Liebig.
Also known as benzenecarbonal, benzaldehyde as well as other similar chemicals are natural contents of several foods. In fact, the major amount of benzaldehyde consumed by people is obtained from natural and traditional foods like almonds.
Apples, apricots, almonds and cherry kernels enclose considerable amounts of a natural compound called amygdalin, which is basically a glycoside. Amygdalin breaks down into benzaldehyde, two glucose molecules and hydrogen cyanide due to enzyme catalysis.
A neutral liquid aldehyde, the odour of benzaldehyde is similar to that of almond. This organic compound boils at 180°C and dissolves in ethanol, but it is not soluble in water. Benzaldehyde forms in two different ways - first due to incomplete oxidation of benzyl alcohol; and secondly, following the oxidation of benzoic acid. It is often referred to bitter almond oil, because this organic compound forms when the glucoside amygdalin found in bitter almond kernels as well as pits of apricots is hydrolyzed. In other words, benzaldehyde is formed by smashing these kernels or pit and subsequently boiling them in water. This process also results in the formation of glucose and a poisonous gas hydrogen cyanide. Alternatively, benzaldehyde is also formed by oxidation of benzyl chloride or toluene. Another way to form benzaldehyde is to treat benzal chloride using any alkali, for instance sodium hydroxide. It is worth mentioning here that benzaldehyde is widely used to make certain aniline dyes as well as other products, including flavourings and perfumes.
Benzaldehyde can be distinguished by its typical appearance and nature. In its pure form, this organic compound is a neutral liquid, while the variety used for industrial products may be colorless or even have a yellowish tinge. The aroma of benzaldehyde is similar to that of bitter almond. At the same time, this liquid organic compound blends well with benzene, ether, chloroform and ethanol.
As discussed above, fractional oxidation of benzyl alcohol results in the formation of benzaldehyde, which readily oxidizes to form benzoic acid. Moreover, additional products can be obtained from benzaldehyde by reacting it with either sodium bisulfite or hydrocyanic acid. This organic compound can also be produced by oxidizing benzyl chloride or toluene. Alternatively, you may treat benzal chloride with any alkali like sodium hydroxide to obtain benzaldehyde, which is mainly used for synthesizing various other organic compounds ranging from plastic additives to pharmaceuticals. Moreover, benzaldehyde is a vital intermediary for processing flavoring compounds and perfumes.
Benzaldehyde forms the primary step while synthesizing different compounds to make perfumes. This organic compound goes through oxidation as well as reduction at the same time when it is treated with alcoholic potassium hydroxide, resulting in the production of benzyl alcohol and potassium benzoate.
When treated with alcoholic potassium cyanide, benzaldehyde can be converted into benzoin. This organic compound produces cinnamic acid when treated with acetic anhydride and anhydrous sodium acetate. It is worth noting here that any compound that does not possess alpha-hydrogen atoms is unable to form an enolate ion. Such compounds also do not go through aldol condensation and electrophilic alpha-substitution.
When treated with any concentrated alkali (as in Cannizaro's reaction), aromatic aldehydes like formaldehyde and benzaldehyde may go through simultaneous oxidation and reduction (disproportionation). In such conditions, one aldehyde molecule is reduced to an analogous alcohol, while another molecule is oxidized to form a carboxylic acid salt at the same time. However, the pace of this reaction is subject to the substituents present in the aromatic ring of the aldehyde. Basically, there are two varieties of aldehydes - aromatic and aliphatic. Both types of aldehydes can go through crossing reaction to convert into aromatic alcohols and formaldehyde.
Benzaldehyde is a vital raw material for several medications, perfumes, dyestuff and the resin industry. In addition, this organic compound can also be employed in the form of a solvent, low temperature lubricant as well as plasticizer. Basically, benzaldehyde is mostly used for flavoring food products. Benzaldehyde is used in small amounts every day to enhance the flavor of tobacco. Although benzaldehyde is widely and commercially used in the form of a food condiment as well as an industrial solvent, benzyl alcohol is mainly used for synthesizing various other compounds ranging from plastic additives to pharmaceuticals. In addition, benzyl alcohol is also a vital transitional product during the production of spices, perfumes and a number of aniline dyes.
Benzaldehyde was used to synthesize mandelic acid as a preparatory reagent. First, hydrocyanic acid reacts with this organic compound and subsequently mandelonitrile is converted to racemic mandelic acid through hydrolysis. According to Stillman and Glacialist LaChepelle, use of aldehydes and benzaldehyde inhibited crystallization of ice during an experiment they undertook in 1966. This was done to put off the formation of dense frost. Moreover, this process can be undertaken to avoid snow slide owing to instable snow cover. Nevertheless, benzaldehyde has not been extensively used for this purpose. This is mainly because it not only destroys vegetation, but also pollutes the water sources when the process is undertaken.
Benzaldehyde is primarily used for making flavours like almond, peach, cherry, nuts and others. The amount of the flavours may be as much as 40 percent. As a flavoring agent, ideally you need to add 3 ml of benzaldehyde per kg of sugar to canned cherry syrup.
In the form of a head of special fragrant, this organic compound is generally used in trace formula for adding aroma, for instance orange flower, lilac, acacia, jasmine, sweet plum, tofu pudding and others. Interestingly enough, benzaldehyde is also used in the manufacture of soaps. In addition, this organic compound can also be used in the form of edible spices for almonds, apricots, berries, cherries, coconut cream, plums, peaches, vanilla bean, walnuts and even spicy flavor. Moreover, benzaldehyde can also be used to flavor wines having the essence of brandy, rum and others.
Moreover, benzaldehyde is also an intermediary of herbicide resistance, anti-amine and also a regulator for plant growth. It is also used in the form of a reagent to determine alkaloid, methylene, ozone, and phenol.