Synthesis and properties of homogeneous models of the Re2O7/Al2O3 metathesis catalyst

✍ Scribed by Gwenael Doledec; Dominique Commereuc

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 243 KB
• Volume: 161
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(00)00284-3

✦ Synopsis

The aim of this work was to synthesize and to study homogeneous models of the rhenium oxide on alumina metathesis Ž . catalyst. A series of aluminium complexes, ArO Al-Y, has been synthesized, where ArO is a 4-substituted-2,6-di-tert-2 Ž . X butylphenoxy ligand, or ArO is a -CH -or -S-ortho bridged-4,4 -di-tert-butyldiphenoxy ligand, and Y is an alkyl or 2 2 Ž . Ž . Ž . chloride ligand. The reaction of ArO Al-Cl with AgReO led to new complexes ArO Al-OReO A . These complexes 2 4 2 3 Ž . Ž . exhibit a low activity in the metathesis of 2-pentene. Complexes ArO Al-R R s iBu, Et react with Re O in THF or 2 2 7 w Ž . x dioxane, giving type B complexes including oligomeric linkages like O Re-Al OAr -O -ReO . They show a fairly high 3 2 3 activity in the metathesis of 2-pentene, with TOF values as high as 100 min y1 . Complexes of type A may be converted into Ž . complexes of type B upon reaction with ArO Al-R in an ether solvent. The high activity of B complexes is tentatively 2 related to the presence of Al-O-Al linkages that are known to induce a powerful bidentate Lewis acidity.