Catalytic conversion of ethanol over gamma-irradiated CuO/MgO

Copper oxide supported on MgO was prepared by the wet impregnation method u sing basic magnesium carbonate and copper nitrate. Thus, a known weight of basic magnesium carbonate was treated with a known amount of copper nitrate dissolved in the least amount of distilled water necessary to make a paste , The paste was dried and then precalcined for 5 h at 400 degreesC, 500 deg reesC or 600 degreesC, respectively. The solids obtained were exposed to di fferent doses of gamma -rays ranging between 0.2 MGy and 1.6 MGy. Catalytic conversion of ethanol was carried out at 250-400 degreesC over Various irr adiated solids employing a micropulse technique, Other techniques used were nitrogen adsorption measurements at -196 degreesC, IR spectroscopy and XRD measurements. The results obtained revealed that all the catalysts investigated were sele ctive towards dehydration, their activities decreasing slightly on increasi ng the precalcination temperature over the range 400-600 degreesC. gamma -I rradiation brought about a progressive decrease in their catalytic activiti es with a dose of 0.8 MGy being sufficient to effect a decrease of more tha n 90% in the initial value. The irradiated catalysts regained virtually ail their initial activity upon increasing the gamma -ray dose to 1.6 MGy. These results were discussed in terms of the progressive removal of OH grou ps From the solid surface by exposure to gamma -irradiation in the range 0. 2-0.8 MGy. The attainment of the initial catalytic activity upon exposure t o a dose of 1.6 MGy was attributed to the creation of surface OH groups due to the interaction between the catalyst samples acid water liberated durin g the early stages of the dehydration reaction.