organic compounds containing in its molecular structure a carbonyl group of the following form: & gt; C = O - called oxo and are divided into two broad categories - aldehydes and ketones.According to the structure of hydrocarbon radicals, these substances are classified into aliphatic, aromatic and alicyclic.The first and second molecules are characterized by a carbonyl group which is linked directly to a benzene ring or side chain.Aldehydes and ketones with a molecular bond of the aromatic series, which have a functional group in the side chain are considered as derivatives of aliphatic carbonyl compounds.
aromatic aldehydes are synthesized in two main ways: the introduction of the carbonyl group in the benzene ring in the course of electrophilic substitution and transformation of the substituents already present in the structure.Aldehydes and ketones include all organic compounds are the most reactive.And in terms of the first chemical much more active second.For aldehydes are very characteristic of the oxidation reaction, substitution, polymerization, addition and condensation.Ketones also do not support the polymerization reaction.
Getting aromatic aldehydes, especially benzaldehyde by oxidation of hydrocarbon compounds air mixture is produced by industrial methods.Such reactions are carried out in chemical plants using oxides of various metals, such as vanadium oxide.Furthermore, for the synthesis of aromatic aldehydes can be applied the methods used in the preparation of compounds of the aliphatic series.
aromatic aldehydes are represented largely insoluble in aqueous medium liquid with a pungent odor of bitter almonds.The more distant from the benzene ring carbonyl group they have, the sharper it becomes their smell.Aromatic aldehydes chemical properties which are largely similar, with the same aliphatic compounds due to the mutual influence of the benzene ring and a carbonyl group, possess certain specific chemical properties and physical characteristics.For example, they can be readily oxidized to the carboxylic acid followed by reduction to the corresponding alcohols and hydrocarbons.A propionaldehyde, which is mixed well with many kinds of organic solvents in the presence of suitable catalysts, is converted to propionic acid and the hydrogenation process - in propanol.
for the synthesis of aromatic ketones can be ispolzony many methods.For example, the alkaline hydrolysis process geminal dihalides, dehydrogenation, oxidation of the corresponding secondary monohydric alcohol, and other compounds.However, the basic procedure for preparing these compounds is the acylation of aromatic compounds.All aldehydes and ketones, having an electrophilic center, well react with a number of nucleophilic reagents.
These aromatic compounds with electron-donating substituents also easily enter into acylation reactions.Ketones of the molecular structure are liquids or solids with a pleasant floral odor insoluble in water, which allows them to be widely used in the perfume industry.
