Phthalonitrile

The Benzoldicarbonitrile form a group of substances, which consist of a benzene ring with two attached nitrile ( -CN) in chemistry. Due to their different arrangement (ortho, meta or para), three constitutional isomers with molecular formula C8H4N2 result.

The trivial name ( phthalonitrile, isophthalonitrile, terephthalonitrile ) are derived in a similar manner from the benzene ( phthalic acid, isophthalic acid, terephthalic acid) from.

History

The first representation of phthalonitrile was reported in 1896 by John Pinnow. It was found as a by- product in the reaction between Orthoamidobenzonitrilhydrochlorid, sodium nitrite and hydrochloric acid in the synthesis of Orthodicyanodiazoamidobenzen. The first direct method for the production of phthalonitrile was introduced in 1907 with the reaction of phthalamide with acetic anhydride. Although the first returns were small, it was the forerunner of today's large-scale synthesis methods.

Representation

Phthalonitrile can be obtained in a one step process by the ammonoxidation of o- xylene in the presence of a vanadium -antimony oxide catalyst at high temperatures ( 480 ° C).

Terephthalonitrile can likewise be obtained by the ammoxidation of p -xylene.

Three methods are described for the preparation of phthalonitrile:

Properties

Terephthalonitrile has the highest melting point due to symmetry of the largest molecule. o- phthalonitrile is readily soluble in alcohol, ether and chloroform, and very soluble in benzonitrile.

Use

Phthalonitrile is used for the preparation of phthalocyanine dyes and is in electro- photographic materials.

Phthalonitrile is also used for the preparation of pesticides, used as a stabilizing additive for aviation fuels and in the rubber industry. It also serves as starting product for the preparation of fluorescent whitening agents and sensitizers for photography.