1-Octene → Ethylene

Beteiligte Stoffe

Reaktionsschritte

The increase in activity of metathesis catalysts brought about by salts has likewise been studied in Inorganica Chimica Acta 359 (2006) 2910-2917. The influences of tin chloride, tin bromide, tin iodide, iron(II) chloride, iron(II) bromide, iron(III) chloride, cerium(III) chloride*7H2O, ytterbium(III) chloride, antimony trichloride, gallium dichloride and aluminium trichloride on the self-metathesis of 1-octene to form 7-tetradecene and ethylene were examined. When using the Grubbs (I) catalyst, a significant improvement in the conversion to 7-tetradecene was observed when tin chloride or tin bromide was added (Table 1; catalyst 1). Without addition of salt, a conversion of 25.8% was achieved; when 5 nCl2*2H2O was added, the conversion rose to 68.5% and when tin bromide was added it rose to 71.9%. Addition of tin iodide resulted in a significant decrease in the conversion from 25.8% to 4.1%. In combination with the Grubbs (II) catalyst (Table 1; catalyst 2), on the other hand, all three tin salts led to only slight improvements in yield from 76.3% (reference experiment without addition) to 78.1% (SnCl2), to 79.5% (SnBr2) and 77.6% (SnI2). When “phobcat” [Ru(phobCy)2Cl2(═ChPh)] is used (Table 1; catalyst 3), the conversion is decreased from 87.9% to 80.8% by addition of SnCl2, to 81.6% by SnBr2 and to 73.9% by SnI2. When iron(II) salts are used in combination with the Grubbs (I) catalyst (Table 3; catalyst 1), the increase in conversion when using iron(II) bromide is higher than when using iron(II) chloride. It may be remarked that, regardless of the type of catalyst used, the conversion when bromides are used is always higher than when the corresponding chlorides are used.

Herkunft & Nachweise