Aromatic alcohols - derivatives of homologuesbenzene, in the radical of which the hydrogen atom is replaced by a hydroxy group. Today in the perfume industry, benzyl alcohol is very often used. The formula of said compound is represented by an alcohol residue and a benzene radical (phenyl) -C6H5CH2OH. The aromatic alcohols are characterized by the isomerism of the side chain radical and the arrangement of the OH group in the hydrocarbon chain. Alcohol in most cases give trivial names.
Benzyl alcohol: methods of obtaining
Aromatic alcohols in the free state are widelyare common in nature. As a rule, they are detected in essential oils. Benzyl alcohol is synthesized from halogenated benzene homologues, in which the halogen is localized in the side chain. These alcohols differ from phenols primarily in that they do not have pronounced acid properties. Benzyl alcohol is also obtained from a natural feedstock that contains esters. After this, the aromatic alcohols obtained are then extracted. Aromatic alcohols are very similar to aliphatic alcohols: alkali metals form alcoholates; upon oxidation, depending on the structure, they are converted to the corresponding aldehydes or ketones; very simply form esters and esters.
Physical properties of alcohols
The first representatives of the homology seriesacyclic alcohols - liquids, and higher alcohols - solids. The first homologues (methanol, ethanol, propanol) have the smell of alcohol, medium (isopropanol, butanol, isobutanol, pentanol, hexanol) - fusel oils, higher - do not smell. Alcohols have a high boiling point, which is due to the association of their molecules with the help of hydrogen bonds. Most of these and other physico-chemical properties of alcohols change with increasing their molecular weight.
It should be borne in mind that in the transitionAlcohols from the liquid to the gaseous state (at boiling) destroy the hydrogen bond. In the ultraviolet spectrum there is an absorption band in the region of 150-200 nm. X-ray and electron diffraction have made it possible to determine the angle of the non-linear C-H bond, equal to 110 ° 25 "As for aromatic alcohols, they have the same properties as acyclic alcohols.These compounds are poorly or completely insoluble in water, in organic solvents.The boiling point is much higher than in the corresponding arenas.The absorption band in the UV and IR spectra is similar to aliphatic alcohols.
Chemical properties of aromatic alcohols
These compounds have the same chemicalproperties, as alcohols alcohols. They form alcoholates, esters and esters, side chain halogen derivatives, and in the oxidation, ketones, aldehydes, and aromatic acids. In addition, these alcohols can exhibit the properties of arenas. For example, they can enter into the reactions of the benzene nucleus-halogenation, nitration, sulfonation, hydrogenation, and the like.
Benzyl alcohol is a solid, goodsoluble in ethanol, poorly in water, melts at 15.3 ° C, boils at 205.8 ° C. It is obtained by alkaline hydrolysis of benzyl chloride, the reaction of benzaldehyde with formaldehyde in the presence of sodium hydroxide, from many essential oils and natural balms. Used as an aromatic substance, odor fixer, solvent in the perfume industry.
Beta-phenylethyl alcohol is a solid,melts at 27 ° C and boils at 222 ° C, dissolves in ethanol. It is a part of pink, clove essential oils. Used as an aromatic substance that has the smell of roses. Also this substance is often used in the perfume and food industries.
Cinnamon alcohol is a solid, melts at33 ° C, it is soluble in ethanol. Contained mainly in the form of ethers in essential oils, odoriferous resins, balms. Aromatic substance with the smell of hyacinth is used in the perfume industry, and also as a raw material for the synthesis of most odorous substances.
