PERKIN, SIR WILLIAM HENRY English chemist, the discoverer of aniline dyes, was born in London on March 12, 1838. He attended the City of London school and devoted all his spare time to chemistry; in 1853 he entered the Royal college of chemistry and studied under A. W. von Hof mann (q.v.) to whom he later became an assistant. He devoted his evenings to private investigations in a rough home-laboratory, and was inspired by some remarks of Hofmann's to undertake the artificial production of quinine. In the course of his experi ments (1856) he oxidized impure aniline with potassium bi chromate, and obtained a black product from which he was able to extract a bluish substance with excellent dyeing properties; this was the first artificial, or aniline, dye to be prepared, and it subsequently became known as "aniline purple" or "mauve." A patent for the process of manufacturing the dye was taken out in 1856 (Eng. Pat. 1884) and, with the aid of his father and brother, Perkin set up in 1857 works at Greenford Green, near Harrow, for the commercial production of "mauve." In this way the great aniline dye industry, which has assumed such large proportions, was founded. (See ANILINE DYES.) Perkin also had an impor
tant share in the development of artificial alizarin (q.v.), which has now entirely replaced the red dye of the madder root. C. Graebe and C. T. Liebermann in 1868 prepared the substance synthetically from anthracene, but their process was not prac ticable on a large scale ; soon afterwards Perkin patented a com mercial process which secured for his Greenford Green works a monopoly of alizarin manufacture for several years. He also carried out investigations on other dyes and on flavouring ma terials, in the course of which he synthesized coumarin (q.v.), the odoriferous principle of woodruff and the tonka bean. About 1874 he abandoned manufacture and devoted himself exclusively to research. In 1878 he discovered the "Perkin reaction," for the preparation of unsaturated acids, e.g., cinnamic acid (q.v.) which depends on the condensation of aromatic aldehydes with the salt of a fatty acid. Later he made a comprehensive study of the relation between chemical constitution and the rotation of the plane of polarization of light in a magnetic field (see Iso