Functionalization catalytic performance evaluation

Preparation and characterization of two-dimensional zirconium phosphonate derivatives in either crystalline or amorphous forms have been investigated. Two composite zirconium phosphonates in single crystal phase have also been investigated and characterized by XRD, i c-, and 3ip-MASNMR. The catalytic performance over zirconium phosphonates are evaluated by hydrolysis of ethylacetate in aqueous solution. When the composite zirconium phosphonate is composed with an acidic function and with a hydrophobic function in single crystal phase, the catalytic activity in aqueous medium showed higher activity than that of single acidic zirconium phosphonate. The composite materials become accessible to any reactant molecule and improve hydnq>hobicity. 

In the following sections, we will review the known homogeneous transition metal nitrosyl catalyses with regard to the described three major NO functions. Not only the catalytic performance, but also the reaction mechanisms with reference to the various roles of the nitrosyl group in catalytic reaction courses will be evaluated. 

The catalytic performance of the functionalized MIL-101 was evaluated in the condensation of benzaldehyde and ethyl cyanoacetate in cyclohexane as solvent at 80 °C. A high conversion was obtained with all the ED-, DETA-, and APS-MIL-101 MOF catalysts having a high selectivity for traws-ethyl cyanocinnamate (turnover... 

Assuming that substituted Sb at the surface may work as catalytic active site as well as W, First-principles density functional theory (DFT) calculations were performed with Becke-Perdew [7, 9] functional to evaluate the binding energy between p-xylene and catalyst. Scalar relativistic effects were treated with the energy-consistent pseudo-potentials for W and Sb. However, the binding strength with p-xylene is much weaker for Sb (0.6 eV) than for W (2.4 eV), as shown in Fig. 4. 

Takeuchi et al. 7 reported a membrane reactor as a reaction system that provides higher productivity and lower separation cost in chemical reaction processes. In this paper, packed bed catalytic membrane reactor with palladium membrane for SMR reaction has been discussed. The numerical model consists of a full set of partial differential equations derived from conservation of mass, momentum, heat, and chemical species, respectively, with chemical kinetics and appropriate boundary conditions for the problem. The solution of this system was obtained by computational fluid dynamics (CFD). To perform CFD calculations, a commercial solver FLUENT has been used, and the selective permeation through the membrane has been modeled by user-defined functions. The CFD simulation results exhibited the flow distribution in the reactor by inserting a membrane protection tube, in addition to the temperature and concentration distribution in the axial and radial directions in the reactor, as reported in the membrane reactor numerical simulation. On the basis of the simulation results, effects of the flow distribution, concentration polarization, and mass transfer in the packed bed have been evaluated to design a membrane reactor system. 

The series of dealuminated samples prepared by AHFS treatment were evaluated for the catalytic decomposition of DCE, which was considered as model reactions of chlorinated VOC destruction. The results of DCE and TCE conversion as a function of of reaction temperature over Y zeolites are shown in Fig. 3. It was noted that all dealuminated samples except H-Y(d64"/o) zeolite exhibited an enhanced performance in comparison with that of the parent material. The 50% dealuminated sample H-Y(d5o%) was the most active catalyst achieving complete conversion at 350 C for DCE and at 550°C for TCE. The following order of activity for chlorinated VOC conversion was observed H-Y(djo%)>H-Y(d32%)>H-Y(di6%)>H-Y>H-Y(d64%). Hence, H-Y(dso%) zeolite showed a light-off temperature or Tso (temperature at which 50% conversion was attained) of 265°C lower than that of H-Y(d32%), H-Y(di6%) and H-Y, 280, 300 and 325"C, respectively. H-Y(d64%), however, showed a less active behaviour with a T50 value of 350 C. Unlike DCE, TCE combustion required significantly higher temperatures [24,25], T50 values were 475, 475, 500, 510 and 520°C over H-Y(d5o%), H-Y(d32%), H-Y(di6 /.), H-Y and H-Y(d64%), respectively. 

The objective here is to simulate duct reactor performance with nonuniform catalyst activity and identify optimal deposition strategies when reactant diffn-sion toward the active surface is hindered, particularly in the corners of the flow channel. Both types of power-function profiles, listed in Table 23-3, are evaluated for n = 1,2,4, 8. The delta-function distribution has been implemented by Varma (see Morbidelli et al., 1985) to predict optimum catalyst performance in porous pellets with exothermic chemical reaction. Nonuniform activity profiles for catalytic pellets in fixed-bed reactors, in which a single reaction occnrs, have been addressed by Sznkiewicz et al. (1995), and effectiveness factors for... 

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