Epoxidation kinetics

Complex inactivation kinetics caused by enzyme-catalyzed decomposition of epoxide kinetic constants calculated from initial rates of inactivation. Approximate value calculated from half-life in the presence of 50 mAf inhibitor. 

As stoich. [Ru(0)(bpy)(tmtacn)]VCH3CN it functioned as a competent (sic) epoxidant for alkenes, though the products were often contaminated with by-products (e.g. fran -stilbene gave fran -stilbene oxide and benzaldehyde cw-stilbene gave cis- and trans- epoxides). Kinetics of the epoxidation of norbomene and styrene were reported, with activation parameters measured and discussed [682]. Kinetics of its non-stereospecific, stoicheiometric epoxidation of aromatic alkenes in CH3CN were studied, and the rates compared with those of oxidations effected by other Ru(IV) 0x0 complexes with N-donors, e. g. [Ru(0)(tmeda)(tpy)] ", trans-[Ru(0)(Cl3bpy)(tpy)] " and [Ru(0)Cl(bpy)(ppz )] + [676]. 

For Mo catalysts Chong and Sharpless [473] have proposed a reaction sequence (Fig. 1.12) consistent with the observed epoxidation kinetics ... 

T. Luts, H. Papp, Novel ways of Mn-salen complex immobilization on modified silica support and their catalytic activity in cyclooctene epoxidation, Kinet. Catal. 48 (2007) 176. 

A factorial design of kinetic experiments utilizing Au/TS-1 was the first study of propylene epoxidation kinetics in the absence of catalyst deactivation [55]. The adoption of a factorial design allowed for the examination of the largest statistically significant number of reaction conditions centered around the standard reaction mixture of 10/10/10/70 vol% Fl2/02/propylene/diluent while avoiding flammable conditions. The experimental results [55] from the evaluation of three Au/TS-1 catalysts showed that PO production could be approximated using the power rate law expression rpo = k [Fl2] [O2] [CsHe]... 

The epoxidation kinetics was investigated in acetic acid in the temperature range of 10-40 °C. The dilution with acetic add should not affect the epoxidation rate because PAA in such systems is almost completely assodated with acetic acid even if not additionally diluted with acetic add. It was foimd that PAA was consumed exclusively for epoxidation within the given temperature range and time. 

From the epoxidation kinetics of substituted cyclohexene derivatives with aqueous solutions of PAA one can conclude that the probability of side reactions... 

The solvent plays a major role in the process. Its selection is strictly dependent on the properties of both the catalyst and the redox system. More specifically, it must be stable to oxidative degradation by TS-1, which means that it should be chemically inert or sterically hindered. The solubility of all the components of reaction mixture has to be high, to minimize the voliune of the working solution. This is a difficult task to accomplish, since solubility properties of reagents and products differ significantly. Third, the solvent should promote epoxidation kinetics (12). 

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