ChemS Graduate Seminar: Hydro-Metathesis of Long-Chain Olefin using Well-Defined Silica-Supported Tungsten (VI), Molybdenum (VI) and Tantalum (V) Catalysts

Oct 16 2016 12:00 PM - Oct 16 2016 01:00 PM

​Hydro-Metathesis of Long-Chain Olefin using Well-Defined Silica-Supported Tungsten (VI), Molybdenum (VI) and Tantalum (V) Catalysts​​​​

ABSTRACT: Olefin metathesis has become a standard methodology for constructing C-C bonds in many organic transformation reactions.  This owed to the numerous types of metathesis reaction that have been developed, for example, ring-closing metathesis (RCM), enyne metathesis, ring-opening ring-closing metathesis, self-metathesis and cross metathesis etc…But the one step conversion of olefin to alkanes has not been studied much.  In literature we found only one example where Ta-H and hydrogen was used for conversion of propene to different chain length alkanes (hydrometathesis reaction)(1). With this knowledge we thought to study the hydrometathesis using liquid olefin (decene).  Another aspect to use decene comes from our previous experience on metathesis of n-decane where first step is conversion of decane to decene and subsequently to different chain length alkanes with W-alkyl/alkyledene catalyst.  In this way it would be easy for us to use different catalyst and compare them with parent catalyst in terms of TON. Surprisingly, we found 100% conversion with TON of 1010 using supported WMeonto SiO2(700)  [≡Si-O-W(Me)against the previous results for n-decane showing 20% conversion and TON of 153 (2).

Here we disclose the hydrometathesis reaction of decene using W(VI), Mo(VI) and Ta(V) alkyl catalyst in batch reactor condition.

 

(1) Polshettiwar, Vivek, et al. "“Hydro‐metathesis” of Olefins: A Catalytic Reaction Using a Bifunctional Single‐Site Tantalum Hydride Catalyst Supported on Fibrous Silica (KCC‐1) Nanospheres." Angewandte Chemie International Edition 50.12 (2011): 2747-2751.

 

f nDecane: Drastic Improvement in Alkane Metathesis with WMe5 Linked to Silica–Alumina." Chemistry–A European Journal 21.16 (2015): 6100-6106.