The synthesis of hydrocarbons via hydrogenation of carbon monoxide was investigated over cobalt-nickel-zirconia catalysts of various compositions in combination with zeolite HZSM-5 in "mixed bed" and "follow bed" arrangements. These combinations resulted in the formation of aromatics in amounts as high as 30-35 wt% under relatively mild operating conditions (1 atm, 250-280°C). Although the olefinicity of Cr and C, fractions in the product stream was higher in the mixed bed compared to the follow bed arrangement, the selectivities to aromatics were comparable in the two bed arrangements. The aromatic selectivity was found to be sensitive to operating conditions. The formation of aromatics was favored at high HZSM-S/metal catalyst ratios, low space velocities and high reaction temperatures. The product distributions obtained using various metal/zeolite bifunctional catalysts have been discussed.

Performances of manganese oxide‐supported cobalt, nickel, and their combinations of varying compositions have been investigated for CO hydrogenation to lower hydrocarbons using a fixed bed microreactor at atmospheric pressure and temperatures ranging from 525 to 575 K. While Co/MnO was found to exhibit high selectivity to olefins in the C2–C4 range, the total yield of hydrocarbons was low. Addition of nickel to cobalt gave a stable catalyst having improved hydrocarbon yields while still retaining good olefin selectivity. The effect of operating conditions on product distribution was studied. Lower space times and higher temperatures favored olefin selectivity. A comparison of Ni and Co catalysts on various support materials was made. MnO‐supported Co catalyst gave significantly higher olefin/paraffin ratio than that obtained using conventional supports such as SiO2 or Al2O3. It was found that Co/MnO exhibited high water‐gas shift activity, and suppressed hydrogen uptake due to strong metal‐support interaction which favored olefin formation. This can be explained on the basis of competitive adsorption of water and hydrogen on the same surface sites resulting in low hydrogenation activity but improved olefin selectivity.

Cetane number is a measure of ignition quality, specifically ignition delay, of diesel fuel. It is an engine measure of a kinetic phenomena. While it is typically inappropriate to use a thermodynamic measure, such as molecular structure, to predict kinetic behavior, molecular structure does correlate

Recent developments in the C4 process for making maleic anhydride have been critically reviewed. Major work in this field deals with the development of catalysts for this reaction. V-P-0 catalysts often containing activating agents have been widely described in the patent literature to give good yields of maleic anhydride. Some important characteristics of vanadiumphosphorus catalysts have been discussed. Kinetics and mechanisms of butene and butane oxidation reactions to maleic anhydride have also been presented.

The synthesis of hydrocarbons from syngas was studied over a zirconia-based cobalt-nickel catalyst (FT catalyst) alone as well as mixed with zeolite HZSM-5 at 101.3 kPa in a 12.7 mm i.d. down flow reactor. The product distribution was recorded as a function of time-on-stream for several days of continuous operation under fixed operating conditions of 250°C and Hz/CO = I . For the FT t HZSM-5 system, a dramatic variation in the product distribution takes place during the first 24 h of operation. A comparison of time-on-stream results obtained using FT catalyst alone and mixed with HZSM-5 suggests that the reactions leading to the build-up of overall product distribution are slower over HZSM-5 compared to those taking place over R catalyst. These diffcrcnces have been attributed to the different nature of reactions taking place over the two components of the mixed catalyst system. Analyses of the coke on the deactivated catalysts are also reported.