1. Yitzhaki, D., Landau, M. V., Berger, D. and Herskowitz, M., " Deep Desulfurization of Heavy Atmospheric Gas Oil with Go-Mo-Al Catalysts. Effect of Sulfur Adsorption ", Appl. Catal., 122, 99 – 110 (1995).

  2. Landau, M.V. and Herskowitz, M., " Silica-Supported Crystals of ZSM-5 Zeolite: Effect of Zeolite Loading ", Stu. Surf. Sci., Catal., 94, 357-62 (1995).

  3. Landau, M. V., Berger, D. and Herskowitz, M., " Hydrodesulfurization of Methyl-Substituted Dibenzothiophenes: Fundamental Study of Routes to Deep Desulfurization ", J. Catal., 158, 236-245 (1996).

  4. Landau, M.V., Kaliya, M.L., Herskowitz, M., van den Oosterkamp, P.F. and Bocque, P.S., " Produce Light Olefins from Paraffins by Catalytic Oxidation ", CHEMTECH, 24-29 (February 1996).

  5. Berger, D., Landau, M.V., Herskowitz, M. and Boger, Z., "Deep Hydrodesulfurization of Atmospheric Gas Oil. Effects of Operating Conditions and Modeling by Artificial Neural Network Techniques", FUEL, 74, 907-911 (1996).

  6. Landau, M.V., Herskowitz, M., Givoni, D., Laichter, S. and Yitzhaki, D., "Medium - Severity Hydrotreating and Hydrocracking of Israeli Shale Oil. I. Novel Catalyst Systems", FUEL, 74, 858-866 (1996).

  7. Landau, M.V., Herskowitz, M., Givoni, D., Laichter, S. and Yitzhaki, D., "Medium - Severity Hydrotreating and Hydrocracking of Israeli Shale Oil. 2. Testing of Novel Catalyst Systems in a Trickle Bed Reactor", FUEL, 77, 3-13 (1998).

  8. Landau, M.V., Herskowitz, M., Givoni, D., Laichter, S. and Yitzhaki, D., "Medium - Severity Hydrotreating and Hydrocracking of Israeli Shale Oil. 3. Hydrocracking of Hydrotreated Shale Oil and its Atmospheric Residue for Full Conversion of Motor Oil", FUEL, 77, 1589-1597 (1998).

  9. Landau, M.V., Kogan, L.O., Herskowitz, M., "Tail Selective Hydrocracking of Heavy Gas Oil in Diesel Production", Stu. Surf. Sci., Catal., 106, 371-78 (1997).

  10. Landau, M.V., Kogan, S.B., Herskowitz, M., "Dehydrogenation of methoxyisopropanol to methoxyacetone on supported bimetallic Cu-Zn Catalysts", Stu. Surf. Sci., Catal., 108, 407- 14 (1997).  

  11. Landau, M.V., Kogan, S.B., Taver, D., Herskowitz, M., and Koresh, J.E., "Selectivity in Heterogeneous Catalytic Processes", Catalysis Today, 36, 497- 508 (1997).  

  12. M.V.Landau, "Deep Hydrotreating of Middle distillates from Crude and Shale Oils" Catalysis Today, 36 (4), 393-429 (1997).  

  13. Landau, M. V., Kaliya, M. L., Gutman, A., Kogan, L. O., Herskowitz, M. and Van Den Oosterkamp, P. F., "Oxidative conversion of LPG to    olefins with mixed oxide catalysts: surface chemistry and reactions   network.", Stud. Surf. Sci. Catal., 110, 315-326 (1997).  

  14. Vradman, L., Landau, M.V. and Herskowitz, M., "Deep Desulfurization of Diesel Fuels: Kinetic Modeling of Model Compounds in Trickle-bed" Catalysis Today, 48, 41 - 48 1999).

  15. Phillips, J., Weigle, J., Kogan, S. and Herskowitz, M., "Metal Particle Structure: Contrasting the Influence of Carbons and Refractory Oxides" Appl. Catal. A, 173, 273 - 287 (1998).

  16. Landau, M. V., Tavor, D., Regev, O., Kaliya, M.L. and Herskowitz, M., “Colloidal Nanocrystals of zeolite beta stabilized in alumina matrix”, Chem. Mater. 11, 2030 - 2037 (1999).

  17. Kogan, S., Herskowitz, M., Woerde, H.M., Van den Oosterkamp, P.F., “Selective Dehydrogenation of Propane using an Improved Dehydrogenation Catalyst”, Proc.-Ethylene Prod. Conf., 7, 1 - 6 (1998).

  18. Landau, M.V., Varkey, S.P., Herskowitz, M. and Regev, O., “Wetting Stability of Si-MCM-41 Mesoporous Material in Neutral, Acidic and Basic Aqueous Solutions”, Micropor. Mesopor. Mater., 33, 149 – 163 (1999).  

  19. Herskowitz, M., Levitsky, S. and Shreiber, I., “Acoustic Waves in a Liquid-Filled Bed with Microbubbles”, Acustica, 6, 793 – 800 (1999).

  20. Landau, M.V., Vrandman, L., Herskowitz M. and Yitzhaki, D., “Effects of Gaseous and Liquid Components on Rate of Deep Desulfurization of Heavy Atmospheric Oil”, Stud. Surf. Sci. Catal., 127, 393-396 (1999).

  21. I.Vankelecom, A.Wolfson, S.Geresh, M.Landau, M.Gottlieb and M.Herskowitz, “First heterogenisation of Rh-MeDuPHOS by occlusion in PDMS (polydimethylsiloxane) membranes” Chem. Commun., 2407-2408, (1999).

  22.  Pradier, C.M., Rodrigues, F., Marcus, P., Landau, M.V., Kaliya, M.L., Gutman, A. and Herskowitz, M., “Supported Chromia Catalysts for Oxidation of Organic Compounds. The State of Chromia Phase and Catalytic Performance”, Appl. Catalysis B: Environmental, 27, 73 – 85 (2000).

  23. Herskowitz, M., Levitzky, S. and Shreiber, I., “Attenuation of Ultrasound in Porous Media with Dispersed Microbubbles”, Ultrasonics, 38, 767 – 769 (2000).

  24. Kogan, S.B., Schramm, H. and Herskowitz, M., “Dehydrogenation of Propane on Modified Pt/h-Alumina. Performance in Hydrogen and Steam Environment”, Appl. Catal. A, 208, 185-191 (2001).

  25. Wolfson, A., Geresh, S., Landau, M.V., and Herskowitz, M., “Enantioselective Hydrogenation of methyl Acetoacetate Catalyzed by Nickel Supported on Activated Carbon or Graphite”, Appl. Catal. 208, 91-98 (2001).

  26. Landau, M.V., Kaliya, M.L. and Herskowitz, M., “Ammoxidation of p-Cresol to p-Hydroxybenzonitrile. High-Performance Boria-Phosphoria Supported Catalysts”, Appl. Catal., 208, 21-34 (2001).

  27.  L. Vradman, M. Herskowitz, E. Korin, and J. Wisniak “Regeneration of Poisoned Nickel Catalyst by Supercritical CO2 Extraction”, 40, (2001).

  28. Landau, M.V., Vradman, L., Herskowitz, M., Koltypin, Y. and Gedanken, A., “Ultrasonically Controlled Deposition-Precipitation. Co-Mo HDS Catalysts Deposited on Wide-Pore MCM Material”, J. Catal., 201, 22 – 36 (2001).

  29. M.V. Landau, E. Dafa, M.L. Kaliya, T. Sen and M. Herskowitz, “Mesoporous alumina catalytic material prepared by grafting of wide pore MCM-41 with an alumina multilayer” accepted for publication in Micropor. and Mesopor. Materials (2001).

  30. M.V. Landau, A. Gutman and M. Herskowitz, “The role and stability of Li2O2 phase in supported LiCl catalyst in oxidative dehydrogenation of n-butane”, accepted for publication in J.Mol.Catal. (2001).  

  31. T.M. Jyothi, M.L. Kaliya and M.V. Landau, “A Lewis acid catalyst anchored on silica grafted with quaternary alkylammonium chloride moieties “, Angewandte Chem. Int. Ed. Engl., 40, 2884 – 2887 (2001).

  32. Jyothi, T.M., Kaliya, M., Herskowitz, M. and Landau, M., “A Comparative Study of an MCM-41 Anchored Quarternary Ammonium Chloride/SnCl4 Catalyst and its Silica Gel Analogues”, Chem. Commun., (11), 992 – 993 (2001).

  33. S.B. Kogan and M. Herskowitz, “Selective propane dehydrogenation to propylene on novel bimetallic catalysts”, Catal. Commun., 2, 179-184 (2001).

  34. Kaliya, M.L., Malinovskaya, O.V., Landau, M.V. and Herskowitz, M., “Kinetics of Oxidative Dehydrogenation of LPG to Olefins on Dy-Li-Cl-Zr-O Catalyst”, Stud. Surf. Sci. Catal., 133, 113 - 121 (2001).

  1. Herskowitz, M., "Method for Hydrocarbon Synthesis Reactions", USPatent 5,652,193 (1997).

  2. Landau, M.V. and Herskowitz. M., "Process and Catalysts for the Production of Motor Fuels from Shale Oils", EP956326A1(1999).

  3. Kogan, S.B., Koresh, J.B. and Herskowitz, M., "Acid Catalysts on Carbon Fibers", Israeli Patent Appl. (1995).

  4. Kaliya, M., Landau, M.V. and Herskowitz, M., "Catalyst for Oxidative Dehydrogenation of Paraffinic Hydrocarbons and Use of this Catalyst", EP804287B1 (1998).

  5. Kaliya, M., Landau, M.V. and Herskowitz, M., "Catalyst for Oxidative Dehydrogenation of Paraffinic Hydrocarbons and Use of this Catalyst", US6130183 (2000).

  6. Herskowitz, M. and Kogan S., “Catalysts for Converting Paraffinic Hydrocarbons into Corresponding Olefins”, WO9929420A1 (1999).

  7. Herskowitz, M. and Kogan S., “Catalysts for Converting Paraffinic Hydrocarbons into Corresponding Olefins”, EP1051252A1 (2000).

  8. M.V.Landau , M.Herskowitz ,T.M.Jyothi and  M.L.Kaliya, “A novel catalyst and process for the condensation of olefins with   formaldehyde” Israel Patent Appl. No.  141465 (2001).

 

  1. Deep desulfurization of heavy atmospheric gas oil with Co-Mo-Al catalysts. Effect of sulfur adsorption.     Yitzhaki, D.; Landau, M. V.; Berger, D.; Herskowitz, M.. Appl. Catal., A  (1995),  122 (2),  99-110. Transient sulfur adsorption and reaction on partially sulfided and oxidn.-regenerated Co-Mo/Al2O3 catalysts in the hydrodesulfurization of heavy atm. gas oil (HAGO) was studied in batch and trickle-bed reactors at 360° and 5.5 MPa.  The contribution of sulfur adsorption to sulfur removal was significant in cases of 1000-1800 ppm sulfur in the feedstock.  The sulfur level in the hydrotreated HAGO was decreased by 50-350 ppm due to sulfur adsorption on the catalyst for periods of 20-50 h.  The principle of regeneration and adsorption in a trickle bed was demonstrated.  A model that describes the transient adsorption and reaction was proposed.  

  2. Silica-supported crystals of ZSM-5 zeolite: Effect of zeolite loading.     Landau, M. V.; Herskowitz, M..    Applied Catalysis Research Center,  Ben-Gurion University the Negev,  Beer Sheva,  Israel.    Stud. Surf. Sci. Catal.  (1995),  94(Catalysis by Microporous Materials),  357-62. The small crystals of ZSM-5 zeolite were synthesized and stabilized inside the pores of silica gel support.  Changing the synthesis conditions, six samples with zeolite loading 5-90 wt.% and a ref. 100% crystallinity zeolite, all with SiO2/Al2O3 ratio .apprx. 90 were prepd.  Two stages of crystn. were identified: i) formation of small ZSM-5 zeolite crystals (0.025mm) in the supports mesopores and large zeolite crystals (4mm) on the outer surface of the silica pellets followed by ii) faster crystn. in the interior of the carriers pellet.  The second stage proceeds faster giving 50-90 wt.% zeolite/SiO2, leaving empty spaces inside the pellets and fully destroying the carriers pore structure.  At low (<15 wt.%) and high (>50 wt.%) loadings, zeolite crystals are partially blocked with amorphous material.  The optimal zeolite loading providing good accessibility of small crystals and maximal catalytic activity is about 40 wt.%. 

  3. Hydrodesulfurization of methyl-substituted dibenzothiophenes: fundamental study of routes to deep desulfurization.     Landau, M. V.; Berger, D.; Herskowitz, M..    Blechner Res. Center Industrial Catalysis Process Development,  Ben-Gurion Univ. Negev,  Beer-SHeva,  Israel.    J. Catal.  (1996),  159 (1),  236-45. Four catalysts, Co-Mo and Ni-Mo, designed to cover a wide range of activity for arom. ring hydrogenation and two catalysts, zeolite-Co-Mo, with different cracking activities were tested, in the hydrodesulfurization of dibenzothiophene (DBT) and 4,6-dimethyl-DBT (DMDBT) in a fixed-bed reactor at 360° and a hydrogen pressure of 5.4 MPa.  Increasing the hydrogenation activity of the catalysts increased the mole ratio, a, of cyclohexylbenzenes to biphenyls produced from both reactants.  Although a had little effect on the hydrodesulfurization (HDS) rate of DBT, the HDS rate of DMDBT increased significantly with a, approaching the same level as for DBT at a = 2.  Introduction of zeolite HZSM-5 to the Co-Mo-Al catalyst increased the HDS rate of DBT at a lower value of a and decreased that of DMDBT.  No cracking reactions of DBT and DMDBT were detected.  A Co-Mo-Al catalyst contg. HY zeolite displayed significant cracking activity of DMDBT defined by two routes: demethylation of benzenic rings and scission of the C-C bond connecting the benzenic rings.  It resulted in increasing HDS rates of DMDBT about threefold relative to the Co-Mo-Al catalyst, yielding toluene and benzene, at a ratio of about 3, as the main HDS products.  About 80% of the DMDBT desulfurized with HY-Co-Mo-Al catalyst was converted through "cracking" intermediates, 90% of those intermediates being produced through the scission of the C-C bond connecting the benzenic rings.

  4. Produce light olefins from paraffins by catalytic oxidation.     Landau, M. V.; Kaliya, M. L.; Herskowitz, M.; van den Oosterkamp, P. F.; Bocque, P. S. G.    Ben-Gurion University Negev,  Negev,  Israel.    CHEMTECH  (1996),  26 (2),  24-9. LPG contg. 25 wt.% butane, 25 wt.% isobutane, and 50 wt.% propane was oxidatively dehydrogenated in the presence of rare earth oxide-contg. catalysts to give light olefins. 

  5. Deep hydrodesulfurization of atmospheric gas oil. Effects of operating conditions and modeling by artificial neural network techniques.     Berger, D.; Landau, M. V.; Herskowitz, M.; Boger, Z.    Blechner Center,  Univ. Negev,  Beer Sheva,  Israel.    Fuel  (1996),  75(7),  907-911. Artificial neural networks (ANN) are currently being explored in various engineering fields as valuable tools for automatic model-building and knowledge acquisition.  This technique was applied to model hydrodesulfurization of atm. gas oil in a mini-pilot trickle-bed reactor.  Sulfur removal was measured as a function of temp., pressure and liq. hourly space velocity (LHSV) for three sulfur feed concns.  The potential of a two-stage process was also tested.  A set of exptl. data was used to teach a three-layer neural network.  The capability of the artificial neural network to predict the performance was tested with a different set of data.  The agreement between predicted and exptl. values was good.  Temp., LHSV and staging of the process were detd. to be important parameters, while pressure had a little effect over the range tested in this study.

  6. Medium-severity hydrotreating and hydrocracking of Israeli shale oil. 1. Novel catalyst systems.     Landau, Miron V.; Herskowitz, Mordechai; Givoni, Dany; Laichter, Sarit; Yitzhaki, Dany.    Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion Univ. of the Negev,  Beer Sheva,  Israel.    Fuel  (1996),  75(7),  858-866. Novel catalysts were developed for the hydrodesulfurization, hydrodenitrogenation and hydrocracking of Israeli shale oil.  They were designed to operate on feedstock contg. a high level of sulfur and nitrogen.  Two hydrotreating stages and one hydrocracking stage were performed in a batch reactor.  High-activity catalysts with large macropores yielded 97 and 79% conversion of sulfur and nitrogen resp. in the first stage.  1H and 13C NMR and nitrogen distribution measurements among the distn. cuts showed that nitrogen remaining after the first hydrotreating stage comprised low-mol.-wt. hetero-aroms.  A further redn. of the sulfur to 100-200 ppm and nitrogen to 7-30 ppm was obtained in the second stage using zeolite-contg. catalysts.  The major parameters affecting the catalyst performance were tested.  A moderate temp. of 380°C and pressure of 15 MPa were used in both stages.  A selective dual-zeolite hydrocracking catalyst in a third stage yielded 80% of the product in the naphtha boiling range. 

  7. Medium severity hydrotreating and hydrocracking of Israeli shale oil-II. Testing of novel catalyst systems in a trickle bed reactor.     Landau, M. W.; Herskowitz, M.; Givoni, D.; Laichter, S.; Yitzhaki, D.    Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Fuel  (1997),  Volume Date 1998,  77 (1/2),  3-13. Hydrotreating Israeli shale oil at 150 atm, an LHSV of 0.5-1.5 h-1, a temp. of 340-400°C, and a hydrogen to oil ratio of 1500 NL L-1 was studied in a trickle-bed reactor pilot plant packed with two novel catalysts in series.  The first catalyst was Ni-Mo supported on wide-pore alumina and the second catalyst was Co-Mo-Cr supported on combined zeolite HY-alumina carrier.  The desulfurization conversion was higher than 99% over the operating conditions tested while denitrogenation conversion varied over the range 74.3-99.9%.  The pseudo-first-order denitrogenation rate consts. measured at 380°C increased from 1.9 to 2.9 h-1 with increasing distn. temps. of shale oil fractions from <250°C to >380°C.  The apparent activation energy decreased from 29.8 to 23.1 kcal mol-1.  The effects of LHSV and temp. on the structure of shale oil components and hydrocarbons distribution was studied using 1H and 13C NMR and GC-MS methods.  The yields of total liq. product, gasoline, jet and diesel fuels at 380°C and LHSV = 0.5 h-1 were 89.4, 9.3, 22.5 and 65.8 wt% of crude shale oil.  The vol. yield of liq. product per crude shale oil at those conditions was 106.9%.  It contained 160 ppm sulfur and 80 ppm nitrogen.  The quality parameters of motor fuels produced from shale oil by hydrotreating with the two-catalyst system meets certain specifications except gasoline, which displayed low Reid vapor pressure and RON 72.  A 400 h stability test at 380°C indicated no catalysts deactivation.

  8. Medium severity hydrotreating and hydrocracking of Israeli shale oil. III. Hydrocracking of hydrotreated shale oil and its atmospheric residue for full conversion to motor fuels.     Landau, M. V.; Herskowitz, M.; Givoni, D.; Laichter, S.; Yitzhaki, D.    The Blechner Center for Indusrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer-Sheve,  Israel.    Fuel  (1998),  77 (14),  1589-1597. Hydrocracking of hydrotreated Israeli shale oil and its atm. residue was studied at 50 atm hydrogen pressure, LHSV 0.5-4.4 h-1, temp. 350°C and VH2 1500 NL/L in a fixed bed reactor pilot plant with two Ni-Mo-zeolite catalysts based on mono-(HY + Al2O3) and bi-zeolite (HY + H-ZSM-5 + Al2O3) supports.  Desulfurization and denitrogenation and conversion of the feedstock was higher than 99.7% (sulfur content 134 ppm, nitrogen content 4.4 ppm) and it comprised 14 vol.% atm. residue boiling out at 360°C +.  Hydrocracking of the whole hydrotreated shale oil yielded full conversion of atm. residue at LHSV = 2.75 h-1 with mono-zeolite catalyst (A) and at LHSV = 3.5 h-1 with bi-zeolite catalyst (B).  The yield of liq. fuel at these conditions was 87.6 wt% with catalyst A vs. 82.4 wt% with catalyst B.  The contents of light naphtha (< 100°C), heavy naphtha (<200 .ANG.C) and jet fuel (160-280°C) and jet fuel (160-280°C) in the liq. product were 10-15% higher with catalyst B compared with A.  Hydrocracking at full residue conversion produced shifts of the hydrocarbon distributions to lighter mols. inside the hydrocarbon groups, decreased n-paraffins concns. by isomerization and splitting to C5-.  Hydrocracking of the atm. residue with catalyst A yielded full conversion into 360°C-products at LHSV = 0.5 h-1.  The only liq. product obtained in this case at 72.3% yield was naphtha with distn. patterns corresponding to gasoline specification.  The nitrogen content in the liq. hydrocracking products at full conversion of atm. residue fraction of the shale oil was <1 ppm and the sulfur content <15 ppm.

  9. Tail-selective hydrocracking of heavy gas oil in diesel production.     Landau, M. V.; Kogan, L. O.; Herskowitz, M..    Blechner Cent. Ind. Catal. Process Dev.,  Ben-Gurion Univ. Negev,  Beer Sheva,  Israel.    Stud. Surf. Sci. Catal.  (1997),  106(Hydrotreatment and Hydrocracking of Oil Fractions),  371-378. Hydrocracking of straight run heavy atm. gas oil (HAGO) was carried our in a batch high pressure autoclave and fixed-bed high pressure minipilot at 50-55 atm. and temps. 350-390°C with Ni-No-Al catalysts contg. to the Ni-Mo-AL-HY catalyst increased its activity significantly beyond corresponding increase of HY zeolite loading.  It reduced the 90 and 95% b.ps. (BP) of diesel fraction by 17-30°C and pour point (PP) by about 12-20°C depending on zeolite H-ZSM-5 loading and testing conditions.  The overall conversion of HAGO with the bi-zeolite catalyst was not additive yielding lower gasoline yields compared to the sum of the yields obtained with mono-zeolite catalysts.  Based on GC-MS anal. of the HAGO, tail fractions those effects were attributed to increased conversion of the least reactive paraffins as a result of H-ZSM-5 zeolite addn. 

  10. Dehydrogenation of methoxyisopropanol to methoxyacetone on supported bimetallic Cu-Zn catalysts.     Landau, M. V.; Kogan, S. B.; Herskowitz, M.    The Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Stud. Surf. Sci. Catal.  (1997),  108(Heterogeneous Catalysis and Fine Chemicals IV),  407-414. Dehydrogenation of methoxyisopropanol on reduced Cu/Zn catalysts was studied in a fixed bed reactor at 200-300° and atm. pressure.  Al2O3 supported catalysts yielded a lower initial activity compared with SiO2 supported catalysts and displayed a lower deactivation rate.  The main route for deactivation of Cu/Zn/Al2O3 was coking while that of Cu/Zn/SiO2 was the crystn. of the Cu0 phase.  Oxidative regeneration of Cu/Zn/Al2O3 catalyst after 250 h on stream gave complete recovery of initial activity.  Kinetic expts. yielded a Langmuir-Hinshelwood type rate equation. 

  11. Selectivity in heterogeneous catalytic processes.     Landau, M. V.; Kogan, S. B.; Tavor, D.; Herskowitz, M.; Koresh, J. E.    The Blechner Center for Industrial Catalysis and Process Development, Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Catal. Today  (1997),  36 (4),  497-510. The selectivity of several catalytic systems was studied.  Shape selectivity of Pt on carbon fiber catalysts was demonstrated in the competitive hydrogenation of 1-hexene and cyclohexene and in the parallel dehydrogenation of cyclohexanol to cyclohexanone and phenol.  Both reactions were carried out in a gas-phase fixed-bed reactor.  Catalysts prepd. on carbon fibers, contg. pores with small constrictions (5 .ANG.) yielded significantly higher rates of hydrogenation of 1-hexene compared to those of cyclohexene and selectively produced cyclohexanone from cyclohexanol.  Other catalysts, supported on carbon fibers with large constrictions (7 .ANG.) or activated carbon, displayed comparable rates of hydrogenation for both reactants and yielded cyclohexanone as well as phenol from cyclohexanol.  Nitration of o-xylene with nitrogen dioxide was carried out in the gas phase over a series of solid acid catalysts packed in a fixed bed.  Several zeolites, supported sulfuric acid, and sulfated zirconia were tested.  Zeolite H-b was found to be the most active and selective catalyst for the prodn. of 4-nitro-o-xylene.  A preliminary kinetic model indicated that the selectivity to 4-nitro-o-xylene increased with decreasing concn. of nitrogen dioxide.  Alkylation of phenol with methanol was performed on zeolites, supported sulfuric and phosphoric acids, and sulfated zirconia packed in a fixed-bed.  The ratio of o- to c-alkylation, measured at 180° and methanol to phenol feed molar ratio of unity, ranged from 4 with the supported acids to 2 with zeolite H-b.  This ratio decreased with temp.  The ratio of o- to p-cresol changed from about 2 in zeolites in supported sulfuric acid and to 0.5 in phosphoric acid supported on carbon fibers.

  12. Deep hydrotreating of middle distillates from crude and shale oils.     Landau, M. V..    The Blechner Center for Industrial Catalysis and Process Development, Ben-Gurion University of the Negev, P.O. Box 653,  Beer Sheva,  Israel.    Catal. Today  (1997),  36(4),  393-429. A review with 141 refs.  The potential scientific and technol. solns. to the problems that appear as a result of shifting the hydrotreating of crude oil middle distillates and shale oils from the 'normal' to the 'deep' mode are considered on the basis of the reactivities and transformation routes of the least-reactive sulfur-, nitrogen-, and oxygen-contg. compds.  The efficiency of selecting the optimal feedstock, increasing the process severity, improving the catalysts activity, and using alternative catalytic routes are compared, taking into account the specific issues related to deep hydrodesulfurization/hydrodenitrogenation/hydrodeoxygenation, i.e., chem. aspects, kinetics and catalysts. 

  13. Oxidative conversion of LPG to olefins with mixed oxide catalysts: surface chemistry and reactions network. Landau, M. V.; Kaliya, M. L.; Gutman, A.; Kogan, L. O.; Herskowitz, M.; Van Den Oosterkamp, P. F.    Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Stud. Surf. Sci. Catal.  (1997),  110 (3rd World Congress on Oxidation Catalysis, 1997),  315-326. The catalytic performance of 3 mixed oxide catalytic systems V-Mo-, V-Mg and RE-Li-Halogen (RLH) in LPG oxidative conversion was measured at different O/LPG ratios, temps. and WHSV.  At high LPG conversions V-Mo-based catalysts yielded low olefins selectivity and high LPG combustion (CB), V-Mg - medium olefins selectivity by oxidative dehydrogenation (ODH) route and medium LPG CB selectivity, while RLH catalysts displayed high olefins selectivity by ODH and cracking (CR) routes at low CB.  TP-reaction expts. and the effects of O partial pressure on catalytic performance indicated a dynamic interaction of surface O in the ODH, CB and CR routes.  ESCA and TPD measurements detected three types of surface O with different nucleophilicity and bonding strength.  Their distribution correlated with LPG conversion selectivities.  A correlation between catalysts acidity, the surface exposed metal cations concn. and the productivity by the CR route was derived.  The surface basicity was also significant in olefins productivity by the ODH and CR routes.  The selectivity of LPG oxidative reactions were attributed to different intermediates formed on the surface as a result of interaction of C3-C4 paraffins with O atoms of different nucleophilicity.  Both the redox balance of surface metal cations and the acidity-basicity balance are proposed to be significant.

  14. Deep desulfurization of diesel fuels: kinetic modeling of model compounds in trickle-bed.     Vradman, L.; Landau, M. V.; Herskowitz, M..    Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Catal. Today  (1999),  48 (1-4),  41-48. Five catalysts with different hydrodesulfurization (HDS) and hydrogenation activity were tested in HDS of fresh crude heavy atm. gas oil (HAGO) (1.33 wt% S), two partially hydrotreated HAGO (1100 and 115 ppm S) and two model compds., dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT), dissolved in model solvents and HAGO.  Arom. compds. in the liq. decreased significantly the HDS rate of 4,6-DMDBT, esp. for catalysts with high hydrogenation activity.  H2S displayed a similar inhibition effect with all catalysts.  These effects were extremely pronounced in HAGO where the DBT HDS rate decreased by a factor of 10 while 4,6-DMDBT - of 20 relative to paraffinic solvent.  The feasibility of using a highly active hydrogenation catalyst for deep HDS of HAGO is diminished by the strong impact of aroms.

  15. Metal particle structure. Contrasting the influences of carbons and refractory oxides.     Phillips, Jonathan; Weigle, John; Herskowitz, Mordechay; Kogan, Shimshon.    Department of Chemical Engineering,  Penn State University,  University Park,  PA,  USA.    Appl. Catal., A  (1998),  173 (2),  273-287. A review with 87 refs.; an anal. of the literature suggests that there are at least three different characteristics of carbon that can be utilized to generate metal surfaces not found on refractory oxide supports.  First, on graphitic carbon many metals interact very weakly, allowing bimetallic particles to form structures identical to those anticipated for bulk materials.  Of particular significance is the formation of true alloys, both in the bulk and on the (catalytic) surface of the bimetallic particles.  In contrast, on conventional refractory-oxide supports these same structures will not form for certain base-metal/noble-metal pairs.  Instead, a preferential and strong interaction between the more 'base' metal and the support generally leads to preferential segregation of that metal to the refractory oxide interface and, concomitantly, dominance of the catalytic interface by the 'more noble' metal.  As a result of these structural differences, the catalytic chem., both activity and selectivity, of some bimetallic particles supported on refractory oxides and graphitic carbons are dramatically different.  Second, it is clear that it is possible to directly bond metals to unsatd. active sites on high surface-area carbon blacks, activated carbon, etc.  This has been demonstrated to yield thermally stable particles of a unique structure. On refractory oxides, strong interaction generally leads to the creation of complex, ionic-bonded 'interface' phases.  Third, carbon structure can be manipulated to generate shape-selective supports.  This can be done with refractory oxides, but only carbon surfaces are neutral.  Thus, only on carbon will reduced metal readily form.  There is surprisingly little research into any of these phenomena, suggesting there are many opportunities to create unique metal surfaces using carbon as a support.

  16. Colloidal Nanocrystals of Zeolite b Stabilized in Alumina Matrix.     Landau, M. V.; Tavor, D.; Regev, O.; Kaliya, M. L.; Herskowitz, M.; Valtchev, V.; Mintova, S.    Blechner Center for Industrial Catalysis and Process Development and the Chemical Engineering Department,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Chem. Mater.  (1999),  11(8),  2030-2037. Characteristics of zeolite b in stable aq. colloidal soln. were measured by cryo-TEM, DLS, SAXS and after sepn. from soln. by SEM, HR-TEM. Twenty-nanometer spherical zeolite crystals were measured in equil. with flocculates.  Mixing of colloidal zeolite soln. with aluminogel yielded coagulation of both materials.  The mass of zeolite adsorbed by aluminogel increased with decreasing pH.  After calcination, pellets of the composite material at zeolite loading below 60 wt % contained sepd. nanocrystals of 10-15-nm zeolite b stabilized in the mesopores of alumina matrix.  The imbedded zeolite had high structure order and acidity.  No blocking of the zeolite micropores in composite materials was detected.  The activity of zeolite b nanocrystals (imbedded in alumina matrix) in cumene cracking twice that of bulk nanozeolite clusters. 

  17. Selective dehydrogenation of propane using an improved dehydrogenation catalyst.     Kogan, S.; Herskowitz, M.; Woerde, H. M.; Van den Oosterkamp, P. F.    Kinetics Technology International B.V.,  Zoetermeer,  Neth.    Proc. - Ethylene Prod. Conf.  (1998),  7  1-6. A Pt-based catalyst was developed for selective dehydrogenation of propane to propene.

  18. Wetting stability of Si-MCM-41 mesoporous material in neutral, acidic and basic aqueous solutions.     Landau, M. V.; Varkey, S. P.; Herskowitz, M.; Regev, O.; Pevzner, S.; Sen, T.; Luz, Z.    Department of Chemical Engineering,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Microporous Mesoporous Mater.  (1999),  33(1-3),  149-163. The wetting stability of three calcined Si-MCM-41 materials synthesized at room temp. and under hydrothermal conditions with and without pH adjustment and salt addn. was studied by SAXS, SEM, HR-TEM, BET-BJH, FTIR and NMR techniques.  The stability was investigated after wetting with neutral, basic and acidic aq. solns. and further recalcination.  Calcined Si-MCM-41 materials synthesized at room temp. fully degraded under wetting with neutral water.  Crystn. under hydrothermal conditions improved their wetting stability. pH adjustment and NaCl addn. during hydrothermal crystn. led to a further improvement.  It was proposed, based on spectroscopic data, that the structure degrdn. during wetting is caused by hydration of the siloxane structure at the wetting stage followed by siloxane hydrolysis-hydroxylation of strained Si(-OSi-)4 units and their rearrangement-redehydroxylation during recalcination.  This leads to intergrowth of curved hexagonal crystal rods, redn. of the surface area and pore vol. of the material forming a disordered pore structure with increased pore walls thickness.  The water-stable Si-MCM-41 synthesized with pH adjustment and salt addn. was also insensitive to wetting with acidic aq. soln.  However, treatment of this non-strained material with a basic soln. at pH 7.8-8.9 resulted in silica leaching and a redn. in crystallinity, the mean pore diam. and the pore vol.  The rod shape and surface area remained relatively unchanged after wetting at pH 7.8. 

  20. Effects of gaseous and liquid components on rate of deep desulfurization of heavy atmospheric gas oil.     Landau, M. V.; Vradman, L.; Herskowitz, M.; Yitzhaki, D.    Blechner Center for Industrial Catalysis,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Stud. Surf. Sci. Catal.  (1999),  127(Hydrotreatment and Hydrocracking of Oil Fractions),  393-396. The effects of sulfur, nitrogen, bicyclic arom., and monocyclic arom. components in a heavy atm. gas oil (390 °C final b.p. and 1.24 wt.% sulfur) and H2S and ammonia in the gas phase on the hydrodesulfurization (HDS) rate were studied.  The deep hydrodesulfurization stage (Sin 1110-60 ppm) was carried out over Co-Mo-alumina and Ni-W-silica catalysts.  The complete elimination of hydrogen sulfide, ammonia, polycyclic arom. and partial elimination of monocyclic arom. components prior to the deep desulfurization stage increased the overall rate of deep HDS by a factor of about six.

  21. First heterogenization of Rh-MeDuPHOS by occlusion in PDMS (polydimethylsiloxane) membranes.     Vankelecom, Ivo; Wolfson, Adi; Geresh, Shimona; Landau, Miron; Gottlieb, Moshe; Hershkovitz, Moti.    Faculty of Agricultural and Applied Biological Sciences, Centre for Surface Chemistry and Catalysis,  Katholieke Universiteit Leuven,  Louvain,  Belg.    Chem. Commun. (Cambridge)  (1999),   (23),  2407-2408. The first heterogeneous system of Rh-MeDuPHOS, obtained by occlusion of the complex in a PDMS membrane, is reported and tested in the hydrogenation of methylacetoacetate (MAA). 

  22. Supported chromia catalysts for oxidation of organic compounds The state of chromia phase and catalytic performance.     Pradier, C. M.; Rodrigues, F.; Marcus, P.; Landau, M. V.; Kaliya, M. L.; Gutman, A.; Herskowitz, M..    ENSCP, Laboratoire de Physico-Chimie des Surfaces,  Paris,  Fr.    Appl. Catal., B (2000),  27 (2),  73-85. A series of 13 bulk transition metals oxides frequently used as components of full oxidn. catalysts was tested in air oxidn. of n-butane and ethylacetate (EA).  Co3O4, Cr2O3, CuO and MnO2,displayed the best activity, about one order of magnitude higher than the others.  Chromia displayed the highest CO2 productivity.  The activity and CO2 selectivity of Cr2O3 catalyst deposited on mineral supports (SiO2, Al2O3, MCM-41) depended strongly on the supports nature, texture and chromia loading.  XPS, EDAX, XRD, FTIR and TPR-TPO measurements displayed two forms of Cr3+-oxide on silica-supported catalysts: bulk a-Cr2O3 nanocrystals of 10-20 nm and a monolayer of chromia surface species chem. bonded to the support: -Si-O-Cr:O.  The chromia nanocrystals detected by XRD displayed higher activity and selectivity in complete EA oxidn. due to higher redox mobility of chromium cations on their surface compared with grafted chromium silicate species.  The optimized Cr2O3/SiO2 catalyst showed high efficiency in wet oxidn. of amino-3-phosphonopropionic acid, comparable with the best catalysts reported in the literature.

  23. Attenuation of ultrasound in porous media with dispersed microbubbles.  Herskowitz, M.; Levitsky, S.; Shreiber, I.    Department of Chemical Engineering,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Ultrasonics  (2000),  38(1-8),  767-769. The dispersion relation for a granular bed with a small amt. of fine bubbles is formulated and analyzed.  It is assumed that the grain size is much larger than the bubble's radius and that their vol. concn. is small.  The study is motivated by the problem of acoustic diagnostics of fixed bed chem. reactors operating in multiphase flow regime.

  24. Dehydrogenation of propane on modified Pt/q-alumina Performance in hydrogen and steam environment.     Kogan, S. B.; Schramm, H.; Herskowitz, M..    Chemical Engineering Department, Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Appl. Catal., A  (2001),  208 (1,2),  185-191. Dehydrogenation of propane was carried out on several promoted Pt catalysts.  The performance of the catalysts (activity, selectivity and coke formation) was compared in steam and hydrogen environment.  Promoting Pt supported on q-alumina with Sn and K is essential for developing high-performance catalysts.  The combination of optimal catalyst compn. and steam yields high activity and selectivity at low coke formation.  Inferior results were measured with hydrogen as diluent.  Characterization of catalysts using XPS, TEM and chemisorption methods supported the results of reaction data.

  25. Enantioselective hydrogenation of methyl acetoacetate catalyzed by nickel supported on activated carbon or graphite.    Wolfson, A.; Geresh, S.; Landau, M. V.; Herskowitz, M..    Chemical Engineering Department, Blechner Center for Applied Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Appl. Catal., A  (2001),  208 (1,2),  91-98. Heterogeneous enantioselective catalysts based on nickel, tartaric acid and NaBr supported on activated carbon or graphite were characterized and tested in the asym. hydrogenation of Me acetoacetate (MAA).  Nickel crystallite size depended on the type of carbon support, the prepn. conditions and redn. temp. of nickel.  Enantioselectivity increased significantly with increasing nickel crystallite size.  High nickel loading (up to 85 wt.  %) and large crystal size (<5000 A) were examd.  Operating conditions such as temp., hydrogen pressure and catalyst to substrate ratio were varied over a wide range to achieve high enantiomeric excess values.  Enantiomeric excess as high as 91% was obtained with nickel on graphite.

  26. Ammoxidation of p-cresol to p-hydroxybenzonitrile High-performance boria-phosphoria supported catalysts.     Landau, M. V.; Kaliya, M. L.; Herskowitz, M..    Chemical Engineering Department, Blechner Center for Industrial Catalysis and Process Development,  Ben-Gurion University of the Negev,  Beer Sheva,  Israel.    Appl. Catal., A  (2001),  208(1,2),  21-34. Ammoxidn. of p-cresol to p-hydroxybenzonitrile (pHBN) was studied over a large no. of catalysts, mainly oxides of Bi-Mo and B-P. Supported boria-phosphoria on silica displayed superior performance.  Feed compn. and rate had a significant effect on catalyst performance.  The best performance was measured at ammonia, air and nitrogen to cresol molar ratios of 10, 40, 120, resp.  The best performance of fresh catalyst was 63 wt.  % yield of pHBN at P:B molar ratio ranging from 5 to 8 and total oxide content on silica between 10-18 wt.  %. Polymeric deposits on the catalyst generated extensive deactivation.  Regeneration of catalyst in a mixt. of air-nitrogen and steam restored initial performance.  Testing of various promoters indicated that 0.03 wt.  % Pt improved both catalyst stability and regenerability with no effect on selectivity.  Cycled operation of 12 h ammoxidn. and 12 h regeneration over 200 h onstream demonstrated that an av. yield of 55 wt.  % pHBN could be maintained.  A tentative mechanism was derived based on reaction and adsorption measurements: p-cresol and ammonia adsorbed on medium strength acidic sites form p-hydroxybenzylamine as intermediate product. p-Hydroxybenzylamine reacts with oxygen to produce pHBN.  Two different routes for formation of polymeric coke were identified: direct condensation of p-cresol on acidic sites and ammonia-induced condensation of p-hydroxybenzaldehyde formed by p-hydroxybenzylamine oxidn.

  27. Regeneration of Poisoned Nickel Catalyst by Supercritical CO2 Extraction.  Vradman, L.; Herskowitz, M.; Korin, E.; Wisniak, J.  Israel.  Ind. Eng. Chem. Res.  (2001),  40(7),  1589-1590. Regeneration of a thiophene-poisoned Ni-supported catalyst was carried out by supercrit. CO2 extn.  The catalyst activity was measured in the hydrogenation of 2-butanone to 2-butanol at 373 K and 1.7 MPa.  The supercrit. extn. was tested over a range of operating conditions.  Regeneration at 313 K and 41 MPa for 16 h recovered completely the catalyst activity.  Other methods cited in the literature displayed a lower performance in regeneration of Ni catalysts.

  28. Ultrasonically controlled deposition-precipitation. Co-Mo HDS catalysts deposited on wide-pore MCM material. M. V. Landau,* L. Vradman and M. Herskowitz. Blechner Center for Industrial Catalysis and Process Development, Chemical Engineering Department, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel. Y. Koltypin and A. Gedanken. Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.  J. Catal. (2001) 201, 22 – 36. Mo- and Co-oxides were precipitated under ultrasonication treatment from Mo(CO)6 and Co(CO)3NO dissolved in decalin. Introduction of wide-pore Al-MCM-41 material with average pore diameter 8.3 nm and surface area of 840 m2/g increased the Mo-oxide precipitation rate by an order of magnitude. This is a result of ultrasonically induced chemical interaction between metal carbonyl (oxide) and surface silica atomic layer yielding surface silicates (XPS, MAS NMR). It was demonstrated for the first time that ultrasonication of such a slurry yields deposition precipitation of corresponding metal oxide forming a closed packed monolayer at the supports surface (N2-adsorption, HR-TEM, XPS, XRD). Ultrasonically controlled deposition precipitation produced ~45 wt% MoO3 loading, which is the saturation of wide-pore Al-MCM-41 surface monolayer. The high-loading Co-Mo/Al-MCM-41 catalyst prepared by ultrasonically controlled deposition precipitation was 1.7 times more active in HDS of dibenzothiophene, based on reaction rate normalized per catalyst weight, than commercial Co-Mo-Al catalyst.

  29. Mesoporous alumina catalytic material prepared by grafting of wide pore MCM-41 with alumina multilayer. M.V.Landau, E.Dafaa, M.L.Kaliyaa, T.Senb and M.Herskowitz. Department of Chemical Engineering, The Blechner Center for Industrial Catalysis and Process Development Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel,  bWeizmann Institute of Science, Department of Chemical Physics, Rehovot 76100, Israel, Accepted to Micropor. and Mesopor. Materials, 2001. A mesoporous material with surface chemical functionality of alumina was prepared by grafting an alumina multilayer on the surface of MCM-41.  The starting MCM-41 had wide pores and high pore volume so as to avoid substantial narrowing of the pores in successive grafting steps with aluminum butoxide and its conversion to microporous solid. The required material (WPMCM) with wide pore size distribution , surface area 858 m2/g, average pore diameter of 8.2 nm and pore volume of 1.75 cm3/g was synthesized expanding the CTAC surfactants micelles with mesitylene at high solubilizant / CTAC ratio of 10. Repetition Al-butoxide anchoring – hydrolysis – calcination steps yielded a gradual increase of the aluminum content in WPMCM distributed in two states: tetrahedral Al in silica pore walls and clusters of separate alumina phase with octahedral coordination of Al. Four grafting steps produced a material containing 38 wt.% Al2O3 with surface chemical functionality of pure alumina (surface charging, anions adsorption, acidity patterns), surface area of 542 m2/g and narrow pore size distribution with mean pore diameter of 4 nm. This material displayed in alkylation of phenol with methanol 2.3 times higher activity compared with reference alumina of 460 m2/g. In other reactions where performance was determined by acidity of WPMCM support (cumene cracking and isopropanol dehydration) the optimal activity corresponded to 21 wt% Al2O3 where the surface area was >600 m2/g. Five alumina-grafting steps yielded a close-packed alumina multilayer inside the pores of WPMCM that decreased the surface area of material to 270 m2/g close to conventional activated alumina.

  30. The role and stability of Li2O2 phase in supported LiCl catalyst in oxidative dehydrogenation of n-butane. M.V. Landau*, A. Gutman and M. Herskowitz, The Blechner Center for Industrial Catalysis and Process Development, Chemical Engineering Department, R. Shuker and Y. Bitton, Department of Physics ,D. Mogilyansky ,Institutes of Applied Research, Ben-Gurion University of the Negev, Beer-Sheva ,Accepted to J. Mol. Catal. Chemistry, 2001. This study was aimed at defining the role of active phases in supported LiCl and LiCl-DyCl3 catalysts in the catalytic oxidative dehydrogenation (ODH) of n-butane. LiCl supported on silica displayed the highest activity and selectivity in n-butane ODH compared with other alkali metals halides. Addition of DyCl3 increased activity.  TPO, XRD and RLS data showed that LiCl and DyCl3 formed during the preparation stage were converted to Li2O2 and DyOCl phases, respectively, by calcination in air at >400oC.  The results of separate TPR experiments (O2-oxidation - butane reduction) along with XRD, RLS and XPS data proved that butane reacts mainly with oxygen species of Li2O2 phase at ODH conditions, probably attributed to [Li+O-] pairs. The proposed functions of chlorine and dynamic oxygen in the oxidative dehydrogenation of butane are consistent with the activity, selectivity and stability of silica and magnesia supported catalysts. High thermal stability of Li2O2 in oxidized LiCl catalyst was attributed to formation of protective Li2O.LiCl surface layer. Deactivation of LiCl/SiO2 catalyst in n-butane ODH is caused by formation of Li-silicates at reaction conditions while LiCl/MgO display a stable performance.

  31. A Lewis acid catalyst anchored on silica grafted with quaternary alkylammonium chloride moieties T.M. Jyothi, M. Herskowitz, M.L. Kaliya and M.V. Landau. Blechner Center for Industrial Catalysis and Process Development. Dept. of Chemical Engineering. Ben Gurion University of the Negev. Beer Sheva-84105, ISRAEL Angewandte Chem. Int.Ed.Engl. (2001) 40, 2884 – 2887. This paper describes the preparation of a novel silica supported heterogeneous Lewis acid catalyst. The present methodology of anchoring tin chloride on silica grafted with tetraalkylammonium chloride moieties can be extended to various metal halide catalysts to get stable, recyclable heterogeneous catalysts. As the Lewis acidic ionic liquids, are now a days used in Friedel – Crafts alkylation reactions, a similar type of methodology could be adopted to get solid acid catalysts which are convenient to use in an industrial continuous system leading to clean technology. Also, the accessibility of the active sites to the reactants will be high in the present case as it is away from the vicinity of silica surface. The present catalyst systems are found to be highly active in the Prins condensation of isobutene and formaldehyde to 3-methyl-3-butene-1-ol (MBOH) an important intermediate for industrially valuable terpenes. This is for the first time such a high MBOH yield is achieved. Moreover, it will be interesting to test the activity of these catalyst systems in typical Lewis acid catalyzed reactions aiming at high product selectivity.

  32. A comparative study of a novel MCM-41/ quaternary ammonium chloride/SnCl4 hybrid Lewis acid catalyst and its silica gel based analogue. T.M. Jyothi, M.L.Kaliya, M. Herskowitz and M.V. Landau Blechner Center for Industrial Catalysis and Process Development, Dept. of Chemical Engineering, Ben Gurion University of Negev, Beer Sheva-84105, ISRAEL. Chem.Commun. (2001) (11), 992 – 993. A novel reusable Lewis acid catalyst prepared by anchoring tin chloride on quaternary ammonium chloride functionalized MCM-41 displays higher activity compared to the corresponding silica analogue in terms of turn over rates and product yield in the Prins condensation of isobutene and formaldehyde to isoprenol.

  33. Selective propane dehydrogenation to propylene on novel bimetallic catalysts. S.B. Kogan and M. Herskowitz. Blechner Center for Industrial Catalysis and Process Development. Ben-Gurion University of the Negev, Beer-Sheva, ISRAEL. Catal. Commun., (2001) 2, 179-184. Platinum catalysts supported on corundum and promoted by indium and tin were prepared, characterized by XPS, XRD, TEM and chemisorption and tested with steam and hydrogen as diluents. The characteristics of seven samples were compared with catalysts of similar composition supported on q-alumina. The surface in corundum catalysts is enriched with platinum, in contrast the q-alumina catalysts. The catalytic performance in steam is superior by far to that in hydrogen. The effect of promoters in corundum catalysts on the activity, selectivity and coke level was extremely significant.