Synthesis of Cyclohexene, Cyclohexadiene, and Benzene via Disproportionation of Butadiene over Tungsten Oxide-Silica Catalyst

Abstract

Proper selection of a noninteracting catalyst carrier is important to prevent thermal degradation. The N1AI2O4 coating appears to impart catalytic stability to the Pd-Ni catalyst system compared to AI2O3-SÍO2.4. The optimum reaction conditions for NO reduction over Pd-Ni and Pd-Ru occur at air-to-fuel ratios just slightly rich of stoichiometry, an operating region also characterized by maximum power output and nearly minimum fuel consumption in the IC engine.

Break-in Behavior of a Tungsten Oxide on Silica Catalyst in Propylene Disproportionation

“…In many of these examples it is clear that temporal mass transfer and adsorption-desorption delays are not responsible for break-in but rather there is an essential change in the character of the surface reaction. Break-in exhibited by the tungsten oxide-silica catalyst is not unique for propylene disproportionation; Banks and Heckelsberg (1975) have shown a break-in period of about 3 h for 1,3-butadiene disproportionation at 500-550 °C and 1 atm for the tungsten oxide-silica catalyst.…”

“…Several heterogeneous catalytic systems have been reported for disproportionation (Bailey, 1969). Tungsten oxide on silica has been reported to be particularly desirable because of its high resistance to common poisons such as air and water, and its low coke formation, and this was the system used in this study (Heckelsberg et al, 1968; Banks and Heckelsberg, 1975).…”

Catalytic Metathesis of Alkenes

“…An example of metathesis followed by such a cyclization is the reaction of butadiene over a high-temperature metathesis catalyst. This yields 1,3-cyclohexadiene, obviously via cyclization of the primary metathesis product 1,3,5-hexatriene [13,14].…”

“…This mixture is then passed over a solid metathesis catalyst in the third step, resulting in linear internal alkenes with both odd and even numbers of carbon atoms, in a statistical distribution. This yields about 10-15 wt.-% of the desired detergent-range (C ll -C 14 ) alkenes per pass, which are separated by normal distillation. The isomerization and metathesis catalysts operate at 353--413 K and 3-17 bar, suggesting that a Mo03 /AI20 3 metathesis catalyst is used.…”