DEHYDRATION OF 4-METHYLPENTAN-2-OL OVER LANTHANUM AND CERIUM OXIDES

Lanthanum and cerium oxides have been tested for the title reaction at 623 K and atmospheric pressure in a flow reactor. Lanthanum oxide (pr epared from the corresponding nitrate) gives mainly 4-methylpent-1-ene (80% of the products). Similar results are observed with cerium oxide obtained from the corresponding hydroxide, whereas cerium oxide prepa red from nitrate is less selective towards alk-1-enes. In addition to dehydration, dehydrogenation to 4-methylpentan-2-one is also observed to a limited extent for all the catalysts. Information on the acid-bas e properties of the samples was obtained by adsorption microcalorimetr y of ammonia and carbon dioxide and correlated to reaction selectiviti es. Possible changes in the oxidation state of cerium ions due to the reaction atmosphere are considered. The present results are compared w ith former data for zirconia catalysts. Modification of cerium oxide v ia immersion in NaOH solution does not appear to be useful for improvi ng alk-1-ene selectivity.