Cyclohexene hydrogenation catalyst

Hydrogenation catalysts,such as platinum, palladium, nickel, and so on. In this case the reaction is the reverse of double-bond hydrogenation (15-11 and 15-15), and presumably the mechanism is also the reverse, though not much is known. Cyclohexene has been detected as an intermediate in the... 

Table 6. Cyclohexene hydrogenation-dehydrogenation rates on Pt/SBA-15 nanoparticle encapsulation catalyst series [18].

Figure 2 Hydrogen uptake curves for cyclohexene hydrogenations ran at 35°C and 50 psig of hydrogen in 10% toluene/EtOH with a stirring rate of 1700 rpm. a) AHC-Wilk catalyst b) Homogeneous Wilkinson s catalyst.

Fig. 5.14 Catalytic activities ( ) for the hydrogenation of cyclohexene over catalysts with various Au/Pd composition and average sizes (O) of loading noble metal. The reaction was carried out in a conventional closed system at 23 0.5°C. Conditions initial H2 pressure of 1 atm., cyclohexene of 1.18 mmol, 1-propanol solution of 30 mL [44]...

Kinetic data on cyclohexene hydrogenation catalyzed by RhClL species (n = 1, 2, or 3 L = p-dimethylaminophenyl phosphines) were interpreted in terms of active dimer catalysts (cf. 1), possibly involving coordination through nitrogen as well as phosphorus (82). 

This kinetic equation is applied to the observed kinetic curves obtained in cyclohexene hydrogenation (model reaction) following the molecular hydrogen consumption. Of note, the present kinetic equation provides the value of fe2obs and not kj. However, the real value of the rate constant k2 can be obtained easily using the relationship k2 = k2obs x S/C, where S/C is the substrate/catalyst molar ratio (the catalyst is given as the number of metaUic moles employed). 

This complex has been shown to be an efficient hydrogenation catalyst in test reactions involving cyclohexene.19... 

Phosphinecarbonyl complexes of cobalt have long been known to act as hydrogenation catalysts. In a recent study involving cyclohexene the kinetics of its hydrogenation by the complex [CoH(CO)2(PBun3)2] were studied. Unlike the systems described above, the carbonyl complexes generally require elevated temperature and pressure. The proposed mechanism is given in Scheme 6. 

In the hydroboration/oxidation reaction of 2-cyclohexen-l-ol derivatives the regio- as well as the stereoselectivities can be steered in either of two directions by use of different reagents and reaction conditions. Dialkylboranes, e.g., 9-BBN, give mainly tn rs-l,2-diols, whereas with 1,3,2-benzodioxaborole ( catecholborane") in the presence of the rhodium hydrogenation catalyst Rh(PPh3)jCl the trans-1,3-diols become predominant. The cis- 1,2-diols are usually only formed in trace amounts, but the cis-l,3-diols are always produced as byproducts in 10 — 20% yield (D.A. Evans, 1988). 

Hydrogenation Function of Fresh and Deactivated Hydrocracking Catalysts Cyclohexene Hydrogenation... 

A systematic study of the history of the hydrogenation function ip a series of fresh and deactivated commercial hydrocracking catalysts is reported using cyclohexene hydrogenation as a probe reaction. 

TABLE I. Catalysts Studied for Cyclohexene Hydrogenation Sample wt% S wt% C m /g(BET) Description... 

Figure 3. Variation of rate constant for cyclohexene hydrogenation, k, with time on stream for deactivated catalysts. Conditions reaction temperature, 175°C and total pressure, 225 psia. Key O, AM-C , NU-A , NU-E , AM-D NU-B A, AM-F and A, NU-F.

Two structure insensitive reactions have been selected cyclohexene hydrogenation [6] oil surface Pt sites upon silica and but-l-ene isomerisation on acidic sites in bentonite. Both reactions were studied in differential reactors The former was investigated at 273-313K and lOlkPa Samples (5-lGmg) of catalyst were flushed with N2, pre-reduced in H at 423K for lh, flushed with N2 and then the reactant stream (lOlkPa total pressure cyclohexene N2 H2 = 1,7 89.5 10 1 200cm3.min 1 total flow rale) was introduced and analysed... 

---