Kinetics of epoxidations

A heterogeneous olefin epoxidation catalyst containing both V and Ti in the active site was prepared by sequential non-hydrolytic grafting. The silica was exposed first to VO(OiPr)3 vapor followed by Ti(0 Pr)4 vapor. Formation of propene is evidence for the creation of Ti-O-V linkages on the surface. Upon metathesis of the 2-propoxide ligands with BuOOH, the catalyst becomes active for the gas phase epoxidation of cyclohexene. The kinetics of epoxidation are biphasic, indicating the presence of two reactive sites whose activity differs by approximately one order of magnitude. 

The kinetics of epoxidation were measured in situ as the rate of uptake of olefin by the catalyst, since the epoxide product remains adsorbed on the catalyst surface in the absence of solvent. Addition of 2 Torr cyclohexene vapor (30 pmol) to a 14.2 mg sample of 3 (9.0 pmol Ti, 4.5 pmol V) at room temperature resulted in the loss of the o(C=C) mode in the gas phase IR spectrum over the... 

The determination of catalyst composition and the kinetics of epoxide opening constitute the experimental basis for any mechanistic discussion and catalyst design. For this purpose, Zn-reduced THF solutions of the prepar-atively important 21 [44-46], 22 [47], 23, and 24 were analyzed by cyclic voltammetry, a technique uniquely suited to the investigation of redox active... 

Many authors have dealt with the kinetics of epoxide hydrolysis ducing results important towards an understanding of the reaction mechanism. 

A study has been made of the kinetics of epoxidation of allylphosphinates and of the addition of C-benzoyl-iV-phenylnitrone to vinyl- and allyl-phosphonates. Boron trifluoride stabilizes phosphorus(v) thiocyanates, preventing their isomerization to isothiocyanates. Cleavage of the phosphinothioic methanesulphonic anhydride (97) with aluminium halides yields the phosphinic halide with retained chirality. ... 

Epoxidation of Cycloolefins with Aqueous Peracetic Acid. Kinetics of Epoxidation... 

Yadav, G.D., and D.V. Satoskar, Kinetics of Epoxidation of Alkyl Esters of Undecylenic Acid Comparison of Traditional Routes vs. Ishii-Venturello Chemistry, J. Am. Oil Chem. Soc. 74 397 07 (1997). 

V. V. Goud, A. V. Patwardhan, S. Dinda, and N. C. Pradhan, Kinetics of epoxidation of jatropha oil with peroxyacetic and peroxyformic acid catalysed by acidic ion exchange resin , Chem Eng Sci, 2007,62,4065-76. 

---