“Acid-base properties and active site requirements for elimination reactions on alkali promoted MgO-catalysts”

VERÓNICA K. DÍEZ; JUANA I. DI COSIMO; CARLOS R. APESTEGUÍA

CATALYSIS TODAY

Elsevier

Lugar: Amsterdam; Año: 2000 vol. 63 p. 53 - 62

0920-5861

Base-catalyzed elimination reactions were studied on MgO and alkali-modified MgO catalysts using 2-propanol as a probe reactant. The effect of the acid–base properties on the catalyst activity and selectivitywas investigated by modifying the surface properties of MgO with 1mol% of alkaline metals. Group IA metals promote the formation of medium- and high-strength basic sites, thereby increasing the basic site density and strength. The addition of alkaline promoters improves theMgOactivity for 2-propanol conversion reactions. The selectivity toward dehydration or dehydrogenation products depends on the base site nature, so that intermediate-strength base sites promote acetone formation, whereas high-strength base sites selectively yield propylene. 2-Ppropanol decomposition to acetone and propylene is proposed to take place via an E1cB mechanism in two parallel pathways sharing a common 2-propoxy intermediate. © 2000 Elsevier Science B.V. All rights reserved. two parallel pathways sharing a common 2-propoxy intermediate. © 2000 Elsevier Science B.V. All rights reserved. two parallel pathways sharing a common 2-propoxy intermediate. © 2000 Elsevier Science B.V. All rights reserved. 1cB mechanism in two parallel pathways sharing a common 2-propoxy intermediate. © 2000 Elsevier Science B.V. All rights reserved.