GB544158A - Manufacture of organic nitro-cmpounds - Google Patents

Abstract

544,158. Nitro compounds. KODAK, Ltd. June 21, 1940, No. 10681. Convention date, June 23, 1939. [Class 2 (iii)] Unsaturated nitro compounds are prepared by heating formaldehyde with a nitro compound of the formula R.CH 2 .NO 2 , in which R represents hydrogen, halogen or a substituted or unsubstituted alkyl or aryl group, the re-action being effected in the vapour phase and in the presence of a de-hydration catalyst. In this way, nitromethane is converted into nitroethylene and phenylnitromethane into α-nitrostyrene ; nitroethane, nitropropane, chlornitromethane, #-chlornitroethane and the naphthylnitromethanes can be similarly treated. Temperatures in the range 200‹-500‹ C. are preferably employed, together with space velocities above 600. The de-hydration catalyst may be silica gel, alumina gel, activated alumina, or an hydrated sodium.aluminium silicate, and may be activated by appropriate metal salts and oxides. Thus, silica gel is added to lead acetate solution and the product dried ; the product may be used as such or immersed in a solution of chromium trioxide to give a silica gel-lead chromate catalyst, or in a solution of sulphuric acid to give a silica gel-lead sulphate catalyst ; other acetates such as sodium, magnesium or calcium acetate may be used, with other oxides such as tungsten or molybdenum oxide, and phosphoric acid may be used instead of sulphuric acid. Examples are given. The Specification, as open to inspection under Sect.' 91 also describes the-treatment of furfurylnitromethane and pyridylnitromethane. This subject-matter does not appear in the Specification as accepted.