Redistribution of cations amongst different lattice sites in Cu1-xCoxFe2O4 ferrospinels during alkylation:: magnetic study

A series of Cu1-xCoxFe2O4 (x=0, 0.25, 0.5, 0.75, 1.0) ferrospinels prepared by low temperature coprecipitation method and glycine nitrate combustion method has been studied in gas phase methylation of phenol. Phenol methylation gives mainly o-cresol and 2,6-xylenol as major products and among various compositions, x=0.50 shows good catalytic performance irrespective of the preparation method. The difference in properties of the fresh and spent catalysts was thoroughly characterized by adopting various physico-chemical characterization techniques with special emphasize on magnetic measurements. Various conclusions derived from magnetic study are in good agreement with our previous study of XRD and Mossbauer on same catalyst system. Redistribution of cations occurred during the reaction is evidenced from the increase of saturation magnetization in the spent. Spent x=0.0 shows high T-c close to the value of Fe3O4 indicating that the material has ended with a solid solution of Fe3O4 and CuFe2O4 along with other reduced phases.