Patent GB-777746-A (GB)
Title: Process for the production of cyanopyridines
Inventor: HADLEY DAVID JAMES
IPC: C07D213/85
Filed: 1954-12-09
Abstract: A process for the manufacture of cyanopyridines comprises passing a picoline in the vapour phase together with ammonia and molecular oxygen at an elevated temperature over a vanadium oxide catalyst supported on activated alumina which has been heated to a temperature exceeding 1000 DEG  C. before it is charged with a vanadium compound which is to be converted subsequently into the oxide.  The vanadium oxide is preferably prepared from ammonium vanadate, vanadyl bromide, vanadyl chloride or vanadyl oxalate. Preferably, 10 per cent by weight of vanadium oxide is deposited on the alumina when ammonium vanadate is used as the source and 5 per cent by weight is preferred when vanadyl compounds are used as the source.  The charging of the alumina with ammonium vanadate is preferably carried out in more than one step, each step being followed by the conversion of the charged vanadate into the oxide. Activation of the alumina by heating at a temperature between 1200 DEG  and 1450 DEG  C. is preferred when vanadyl oxalate is used for the impregnation, and temperatures between 1000 DEG  and 1400 DEG  C. are preferred when vanadyl bromide and chloride are used.  Air may be used as the source of the molecular oxygen.  The proportion of picoline in the gas mixture to be treated is preferably 1.5 to 2 per cent by volume, and the proportion of ammonia present is preferably in the ratio of 1.5 to 2 parts by volume to one part of picoline.  The contact time between the gaseous mixture of the reactants and the catalyst is preferably between 0.25 and 7 seconds.  Reaction temperatures of between 300 DEG and 380 DEG  C. are preferred for b -picoline and between 260 DEG and 350 DEG  C. for a - and g -picolines.  The examples describe the preparation of 2-, 3- and 4-cyanopyridines.  References has been directed by the Comptroller to Specification 671,763.ALSO:A supported catalyst for use in the conversion of picolines to corresponding cyanopyridines in the presence of air and ammonia comprises vanadium oxide supported on activated alumina which has been heated to a temperature exceeding 1,000 DEG C. before it is charged with a vanadium compound which is to be converted subsequently into the oxide.  The impregnation of the alumina support with the vanadium oxide may be carried out by moistening the heat-treated alumina with a concentrated aqueous solution of ammonium vanadate, vanadyl chloride, vanadyl bromide or vanadyl oxalate, drying the mixture and heating it in a current of air until the vanadium compound is converted into the oxide. Preferably 10 per cent by weight of vanadium oxide is deposited on the alumina when ammonium vanadate is used as the source and 5 per cent by weight is preferred when the vanadyl compounds are used as the source.  The charging of the alumina with ammonium vanadate is preferably carried out in more than one step, each step being followed by the conversion of the charged vanadate into the oxide.  Activation of the alumina support by heating it at a temperature of between 1,200 and 1,450 DEG C. is preferred when vanadyl oxalate is used for the impregnation, and a temperature of between 1,000 and 1,400 DEG C. is preferred when vanadyl bromide and chloride are used.  Reference has been directed by the Comptroller to Specification 671,763.