Metathesis of methyloleate over methyltrioxorhenium supported on ZnCl2-promoted mesoporous alumina

Methyltrioxorhenium impregnated on ZnCl2-modified mesoporous alumina at Al/Zn ratio of 8–12 was revealed as an effective catalyst for self-metathesis of methyloleate at mild reaction conditions.The use of other promoters either in form of metal chlorides or as other zinc halides did not promote the metathesis of methyloleate as zinc chloride. The enhancement of the activity was not only due to the chloride and/or zinc but could be attributed to the interaction of both elements as Zn–Cl or ZnCl2 bonds with the mesoporous alumina.The results of this research suggest that it is possible to design a heterogeneous catalyst for the efficient and selective self-metathesis of functionalized olefins such as methyloleate and edible oils, avoiding the utilization of expensive homogeneous catalysts or use of toxic promoters such as SnR4 with heterogeneous catalysts.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (107 K)Download as PowerPoint slideHighlights► Highly active 3%MTO/ZnCl2–Al2O3-meso catalyst for methyloleate self-metathesis. ► This catalyst reached high yield of 87% for total metathesis products. ► Al/Zn ratio of 8–12 was revealed optimum for methyoleate metathesis conversion. ► Other metal halides did not promote metathesis of methyloleate as zinc chloride.