A Comparative Characterization of the HPA-MCM-48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

MCM-48 type support materials synthesized by the direct hydrothermal synthesis (HTS) and room temperature synthesis (RTS) methods were incorporated with tungstophosphoric acid (TPA) in the range of 10–40 wt% by using a wet impregnation technique in methanol solutions. Resulting HPA-MCM-48 catalysts were characterized by the XRD, Nitrogen Physisorption, SEM, TEM, EDS, and FT-IR methods in order to determine the effects of different initial synthesis conditions on the catalyst properties. RTS samples were found to have better crystalline structures, higher BET surface areas, and higher BJH pore volumes than HTS samples. They also had slightly higher TPA incorporation, except for the 40 wt% samples, as evidenced by the EDS results. Keggin ion structure was preserved, for both methods, even at the highest acid loading of 40 wt%. It was concluded that the simpler and more economical RTS method was more successful than the HTS method for heteropoly acid incorporation into MCM-48 type materials

Vanadium incorporated high surface area MCM-41 catalysts

High surface area MCM-41 (1452 m(2)/g) and V-MCM-41 materials were synthesized by a direct hydrothermal synthesis method. Characteristic XRD patterns, SEM and AFM photographs indicated no significant change in the morphology of MCM-41 by incorporation of vanadium. XPS and EDS results proved that incorporation of vanadium into the MCM-41 structure was successfully achieved when vanadyl sulfate hydrate was used as the vanadium source. However, use of ammonium vanadate as the vanadium source was not equally successful

Optimization of the locations of side streams in a filter cake washing process

A macroscopic model was developed to perform optimization studies for countercurrent, nonequilibrium, displacement filter cake washing on a belt filter with incoming side streams. Each washing stage was assumed to contain a number of perfect mixing cells connected in series. The optimum locations of the side streams, which yielded the minimum exit solute concentration for the washed cake, were evaluated. Three cases were considered: Incoming side stream added to the wash liquor flow, incoming side stream added to the cake flow and incoming side streams added to both flows simultaneously. A parameter study was performed systematically to determine the effect of washing parameters on the optimum side stream locations

The C-11-radioisotopic study of methanol conversion on V-MCM-41: The influence of methyl iodide on the transformation

The methanol conversion and a feasible methanol co-reaction with methyl iodide were studied on a vanadium incorporated MCM-41 type (V-MCM-41) mesoporous catalyst. which was prepared by a direct hydrothermal synthesis method. Adsorption/desorption as well as conversion derivates of radioactive methanol were easily followed by radioactivity detectors on V-MCM-41. The transformation and coreaction products were analyzed by a gas chromatograph equipped with Radio/FID detectors. The radiodetector was applied to distinguish C-11-derivates from the non-radioactive methyl iodide and its derivates. The radio-labeling method proved methanol transformation to methylal and, in the presence of methyl iodide, decided the roles of methyl group and iodide of methyl iodide in newly synthesized methyl iodide formation in the absence of oxygen gas