GB985319A - - Google Patents

Abstract

985,319. Diazonium halides. KALLE A.G. Jan. 18, 1962 [Jan. 25, 1961], No. 1836/62. Heading C2C. A polyfunctional diazonium halide free from metal salts is prepared by condensing a substituted or unsubstituted diazonium halide with formaldehyde in phosphoric acid, adding to the reaction mixture an aliphatic alcohol, an agent for neutralizing the phosphoric acid and, if the diazonium salt is not a halide, a source of halogen atoms, separating precipitated salts and recovering the polyfunctional diazonium halide from the reaction solution. The aliphatic alcohol used is one which dissolves the condensation product but does not dissolve the phosphoric acid salt formed by the neutralization. The condensation is preferably effected in 85% phosphoric acid at room temperature or a slightly elevated temperature, e.g. 40‹ to 55‹ C., for 20 to 24 hours using equimolar proportions of paraformaldehyde and diphenylamine-4-diazonium salt. The agent used for neutralizing the phosphoric acid is preferably an alkali or alkaline-earth metal hydroxide, carbonate or bicarbonate. The polyfunctional diazonium halide is preferably recovered by evaporating the reaction solution to dryness. In the examples, diphenylamine-4-diazonium chloride, diphenylamine - 4 - diazonium bromide, diphenylamine - 4 - diazonium phosphate, 3 - methoxy - diphenylamine - 4 - diazonium chloride, 2 - methoxy - diphenylamine - 4<SP>1</SP>- diazonium phosphate and 4-methoxy-diphenylamine-4<SP>1</SP>-diazonium chloride are reacted with paraformaldehyde in phosphoric acid. Specification 418,011 is referred to.