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The objectives of this project are to synthesis nanocrystals of highly acidic zeolite Y, encapsulate them within the channels of mesoporous (nanoporous) silicates or nanoporous organosilicates and evaluate the ''zeolite Y/Nanoporous host'' composites as catalysts for the upgrading of heavy petroleum feedstocks. Our results to date are summarized as follows. The synthesis of high surface ordered nanoporous silica of expanded pore diameter of 25 nm (larger than the standard size of 8.4 nm) using trimethylbenzene as a pore size expander was accomplished. The synthesis of zeolite Y nanoparticles with median pore size of approximately 50 nm (smaller than the 80 nm typically obtained with TMAOH) using combined TMABr/TMAOH as organic additives was also accomplished. The successful synthesis of zeoliteY/Nanoporous host composite materials by sequential combination of zeolite precursors and nanoporous material precursor mixtures was implied based on results from various characterization techniques such as X-Ray diffraction, infrared spectra, thermal analysis, porosimetry data. The resulting materials showed pore sizes up to 11 nm, and infrared band at 570 cm{sup -1} suggesting the presence of both phases. Work in the immediate future will be focused on the following three areas: (1) Further characterization of all-silica and aluminosilicate mesoporous materials with expanded pore sizes up to 30 nm will continue; (2) Research efforts to reduce the average particle size of zeolite nanoparticles down to 35-30 nm will continue; (3) Further synthesis of polymer-SBA15 nanocomposites will be conducted by changing the amount and chemistry of the zeolitic precursors added; and (4) Investigation on the catalytic properties of the materials using probe catalytic reactions (such as cumene cracking), followed by catalytic testing for heavy oil conversion.

A comprehensive investigation was conducted towards the synthesis and catalytic evaluation of high surface areas, uniform pore size, mesoporous aluminophosphates (AlPO{sub 4}) as potential catalysts for the upgrading of heavy petroleum feedstock, such as heavy crudes and petroleum residuum. The influence of several synthesis variables (including, the nature of the reactants, chemical composition of reaction mixtures, time and temperature) on the synthesis and physicochemical characteristics of the resulting products was explored. Phosphoric acid and three different aluminum sources, namely, aluminum hydroxide, aluminum isopropoxide and psuedobohemite alumina, were used as the inorganic precursors. Cetyltrimethylammonium chloride (C{sub 16}TACl) surfactant was used as charge compensating cation and structure directing agent in the surfactant-micellar-mediated synthesis pathway employed. Synthesis were conducted from reaction mixtures within the following typical molar composition range: xAl{sub 2}O{sub 3}:P{sub 2}O{sub 5}:yC{sub 16}TMACl: zTHMAOH: wH{sub 2}O, where x = 0.29-2.34, y = 0.24-0.98, z = 0.34-1.95, w = 86-700. Selected materials were evaluated for the conversion of isopropylbenzene (cumene) in order to understand the nature of any acid sites created. The synthesis products obtained depended strongly on the molar composition of the synthesis mixture. A lamellar (layered) phase was favored by synthesis mixtures comprised of low Al/P ratios ( 500 m{sup 2}/g) and pore sizes ranging from microporous (< 1.5 nm) in some products to mesoporous (up to 3.6 nm) in other. Improvement in thermal stability was not observed when Mg and Co or bridging organic functional groups were incorporated with the mesoporous framework. The products showed negligible activity for the conversion of cumene at 300 C. Further research is necessary to investigate alternative synthesis strategies to strengthen and improve the thermal stabilities of these aluminophosphates.

The focus of this project is to improve the catalytic performance of zeolite Y for petroleum hydrocracking by synthesizing nanoparticles of the zeolite ({approx}20-25 nm) inside nanoporous silicate or aluminosilicate hosts. The encapsulated zeolite nanoparticles are expected to possess reduced diffusional path lengths, hence hydrocarbon substrates will diffuse in, are converted and the products quickly diffused out. This is expected to prevent over-reaction and the blocking of the zeolite pores and active sites will be minimized. In this phase of the project, procedures for the synthesis of ordered nanoporous silica, such as SBA-15, using block copolymers and nonionic surfactant were successful reproduced. Expansion of the pores sizes of the nanoporous silica using trimethylbenzene is suggested based on shift in the major X-Ray Diffraction peak in the products to lower 2 angles compared with the parent SBA-15 material. The synthesis of ordered nanoporous materials with aluminum incorporated in the predominantly silicate framework was attempted but is not yet successful, and the procedures needs will be repeated and modified as necessary. Nanoparticles of zeolite Y of particle sizes in the range 40 nm to 120 nm were synthesized in the presence of TMAOH as the particle size controlling additive.

This project focuses on the synthesis of mesoporous aluminophosphates, silicates and aluminosilicates as catalysts for applications in the conversion of large petroleum feedstock compounds to useful middle distillates and naphtha transportation fuels. Summarized herein is our research progress from September 1, 2003, to August 31, 2004. In previous reports it was demonstrated that mesoporous aluminophosphates with neutral framework (containing Al, P and O) could be synthesized, but their thermal stabilities were limited. In general, the materials' pore structure collapsed when calcined at 500-550 C in air or extracted in ethanol/HCl mixture to remove the surfactants, which were used as synthesis templates. New methods to improve the thermal stability of the materials needed to be explored. It was conceived that by adding divalent metals cations, such as Mg and Co, not only that the acid sites would be created by balancing the negatively charged framework (balanced by H{sup +}), but the thermal stability of the materials would be improved. In addition, methods to facilitate the interaction of hydrocarbon substrates with acid sites within the mesoporous are also needed. One concept towards improving this was to incorporate organic functional groups within or attached to the otherwise purely inorganic aluminophosphate (containing Co or Mg) or aluminosilicate pore walls of the mesopores. In the last report we detailed that mesoporous organosilicates were synthesized using block copolymer under acid conditions containing silica and phenylene (-C{sub 6}H{sub 4}-). Materials prepared with phenylene group among the silica pore walls was found to be thermally stable up to 550 C which is almost 100 C higher than the temperature used for the mild hydrocracking of petroleum. It was also highlighted that this area was the subject of recent intense research activities by other researchers. Building on precedence of the last report and on the results of other researchers, we investigated the synthesis of a wide range of mesoporous silicates containing different organic functionalities within the pore walls (using -CH{sub 2}CH{sub 2}-), simultaneously combined with additional organic functional groups extended within the mesopores and grafted through silicate linkages to the pore walls (including (SiO){sub 3}-CH{sub n}SH, (SiO){sub 3}-CH{sub n}NH (SiO){sub 3}-CH{sub n}IM and (SiO){sub 3}-CH{sub n}C{sub 6}H{sub 4}, X is imidazole) for use as potential acid catalysts in petroleum upgrading. Based on modifications to published procedures, we synthesized organic functionalized mesoporous organosilicates described above with surface area greater that 700 m{sup 2}/g, pore volume > 0.73 cm{sup 3}. The materials were stable to ethanolic extraction, but showed various degrees of thermal stability depending on the nature of the organic groups attached. We also investigated the synthesis of a wide range of mesoporous alumiophosphate containing Mg and Co in the matrix. Synthesis was also conducted on organic functionalized aluminophosphates containing similar organic functionalities described above. Syntheses of the phosphates was conducted in basic conditions with cationic surfactant, namely C{sub 16}H{sub 33}N(CH{sub 3})Cl as templates. However, the structure of all the aluminophosphates appear to collapse when the template was removed by extraction or calcination. The catalytic testing phase of the project has commenced with the assembly of a microreactor interfaced with a gas chromatograph. Further research will be focused on use the microreactor to evaluate those potential mesoporous aluminosilicate and alumiophosphate catalyst materials which has maintained some stability, as detailed in this and previous reports, and will also be focused on investigating alternative synthesis approach to strengthen the thermal stability of the aluminophosphates.

This project focuses on the synthesis of mesoporous aluminophosphate and aluminosilicates as catalysts for application in the conversion of large petroleum feedstock compounds to useful middle distillates and naphtha transportation fuels. Summarized herein, is our research progress for September 1, 2001 to August 31, 2002. The synthesis of aluminophosphates in the presence of nonionic surfactants and block co-polymers were explored over a wide range of synthesis variables such as temperature, Al/P ratio, pH and surfactants/polymer concentrations. In most cases, the resulting products were found to be amorphous. A partially ordered aluminophosphate mesophase was obtained in the presence of Brij 56 non-ionic surfactant. Further characterization to determine the phase type (e.g. hexagonal lamellar or cubic) of this product is pending. The amorphous nature of the products obtained using these classes of surfactants are in contrast to highly ordered aluminophosphates mesophases obtained in the presence of cationic quaternary ammonium surfactants, such as cetyltrimethylammonium detailed in a previous report. The synthesis of pure-silica and aluminosilicate mesophases of different type and quality were also conducted over a wide range of variables such as temperature, Si/Al ratio, pH and surfactants/polymer concentrations. However characterization of the phase type and quality of the materials produced is pendingmore » due to a severe and extended malfunction of the X-Ray Diffractometer. Nitrogen porosimetry of selected calcined samples showed various absorption isotherm with some samples showing type IV with a large step in the mesoporous range. Surface area of the samples varied and maximized at approximately 1000 m{sup 2}/g, which is typically reported for materials of this type. Further characterization of the sample will be conducted following repair of the X-Ray Diffractometer.« less

This project focuses on the synthesis of mesoporous aluminophosphate (AlPO) catalysts for application in the acid catalyzed conversion of large petroleum feedstock compounds to Useful middle distillates and naphtha transportation fuels.