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Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, April 1, 1993--June 30, 1993

Description: The presence of potassium or calcium in sol gel catalysts increase the production of C{sub 4} hydrocarbon and that of methane while maintaining high activities. Characterization of catalysts using temperature programmed desorption of carbon dioxide indicates that activity and product distribution over an isosynthesis catalyst depend on its acid-base properties. Low activity was observed for catalysts with very weak basicity, and high oxygenate production for catalysts with strong basicity. An optimum strength of basic sites is crucial to achieve high activity while minimizing the amount of oxygenates. A kinetic model was developed based on the reaction mechanisms, and the simulation from the model produces reasonable fit with the experimental data.
Date: October 6, 1993
Creator: Anthony, R. G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene

Description: The initial objective of this program was to develop a catalyst and process for the conversion of synthesis gas to isobutylene via the isosynthesis process. Preliminary work directed at identifying potential catalysts for this reaction did not have promising results. Therefore, the objectives of this program were revised to the development of a catalyst and process for the conversion of synthesis gas to isobutanol. Two approaches have been investigated in this area: the direct conversion of synthesis gas to higher alcohols and indirect conversion via methanol produced using conventional methanol synthesis technology. The isosynthesis reaction for the conversion of synthesis gas to branched hydrocarbons was pioneered by German workers during World War II The primary products of this reaction are either isobutane or isobutylene depending on the catalyst system used. Thoria-based catalysts were found to give the highest yields, but virtually all of the products were alkanes. More recently, there have been several reports of olefin production using ZrO{sub 2}-based. The preliminary work in this program focussed on the evaluation of ZrO{sub 2} and modified ZrO{sub 2} catalysts for the direct conversion of CO/H{sub 2} to isobutylene via the isosynthesis reaction. All of the catalysts and conditions evaluated in this work gave isobutylene yields of less than 4% which is far below that required for an economically viable process. A summary of the key results from this portion of the project is given in Section 3.6. In view of the poor performance of these catalysts and the lack any encouraging results from other research groups working in the isosynthesis area, this approach was abandoned in favor of approaches related to higher alcohols synthesis.
Date: October 1, 1996
Creator: Barger, P.T.; Spehlmann, B.C. & Gajda, G.J.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Technical progress report No. 5, March 31, 1992--June 30, 1992

Description: The main goal of this contract is to develop a catalyst and technology that will produce iC4{sub 4}{sup =} directly from coal-derived syngas and that is capable of using a lower H{sub 2}/CO ratio (0.5 to 1.0). The research will identify and optimize the key catalyst and process characteristics that give improved performance for CO conversion by a non-Fischer-Tropsch process. This report, which is Quarterly Report No. 5 for contract DE-AC22-91PC90042, covers the testing of various zirconia (ZrO{sub 2}) and bismuth oxide (Bi{sub 2}O{sub 3}) based catalyst systems designed to examine the effects of catalyst preparation and process variables, especially the H{sub 2}/Co ratio. Testing of sol-gel ZrO{sub 2} catalysts with lanthanum (La) or yttrium (Y) addition indicates a decrease in isobutene yield. An attempt to increase catalyst surface area by impregnating Zr on a sol-gel SiO{sub 2} catalyst was unsuccessful. A Bi{sub 2}O{sub 3} catalyst was very low in activity as a result of complete reduction to Bi metal. Increasing the H{sub 2}/CO ratio to 2:1 slightly increased the isobutene yield and improved catalyst stability.
Date: September 10, 1993
Creator: Gajda, G. J.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994

Description: Previous work on isosynthesis (conversion of synthesis gas to isobutane and isobutylene) was performed at very low conversions or extreme process conditions. The objectives of this research were (1) determine the optimum process conditions for isosynthesis; (2) determine the optimum catalyst preparation method and catalyst composition/properties for isosynthesis; (3) determine the kinetics for the best catalyst; (4) develop reactor models for trickle bed, slurry, and fixed bed reactors; and (5) simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for isosynthesis. More improvement in catalyst activity and selectivity is needed before isosynthesis can become a commercially feasible (stand-alone) process. Catalysts prepared by the precipitation method show the most promise for future development as compared with those prepared hydrothermally, by calcining zirconyl nitrate, or by a modified sol-gel method. For current catalysts the high temperatures (>673 K) required for activity also cause the production of methane (because of thermodynamics). A catalyst with higher activity at lower temperatures would magnify the unique selectivity of zirconia for isobutylene. Perhaps with a more active catalyst and acidification, oxygenate production could be limited at lower temperatures. Pressures above 50 atm cause an undesirable shift in product distribution toward heavier hydrocarbons. A model was developed that can predict carbon monoxide conversion an product distribution. The rate equation for carbon monoxide conversion contains only a rate constant and an adsorption equilibrium constant. The product distribution was predicted using a simple ratio of the rate of CO conversion. This report is divided into Introduction, Experimental, and Results and Discussion sections.
Date: May 6, 1994
Creator: Anthony, R.G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, October 1, 1992--December 31, 1992

Description: The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed reactors, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. The goals for the quarter include: (1) Conduct experiments using a trickle bed reactor to determine the effect of reactor type on the product distribution. (2) Use spherical pellets of silica as a support for zirconia for the purpose of increasing surface, area and performance of the catalysts. (3) Conduct exploratory experiments to determine the effect of super critical drying of the catalyst on the catalyst surface area and performance. (4) Prepare a ceria/zirconia catalyst by the precipitation method.
Date: February 1, 1993
Creator: Anthony, R.G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, July 1, 1992--September 30, 1992

Description: A series of zirconia catalysts prepared by a modified sol gel procedure, coprecipitation with ammonium hydroxide, and by a hydrothermal method were evaluated for catalytic activity. These catalysts were prepared containing silicon, thorium, titanium, cerium and the alkali metals. A catalyst containing 2% thorium on zirconia was the most active. The isobutylene and isobutane selectivity were 19.4 wt % and 1.82 wt %, respectively. Macro- and micro-kinetic models indicate that C0{sub 2} formation inhibits the rate of CO conversion, hydrogen is dissociatively adsorbed, and CO is molecularly adsorbed. The microkinetic model indicates the strengthening of the metaloxygen bond might increase the production rate of isobutylene.
Date: November 13, 1992
Creator: Anthony, R.G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Application of the solubility parameter concept to the design of chemiresistor arrays

Description: Arrays of unheated chemically sensitive resistors (chemiresistors) can serve as extremely small, low power consumption sensors with simple read out electronics. Most work has focused on the exotic polymeric organic metals, but here the authors report new results on carbon loaded polymer composites, as well as polymeric ionic conductors. They use the solubility parameter concept to understand and categorize the chemiresistor responses and, in particular, they compare chemiresistors fabricated from polyisobutylene (PIB) to results from PIB coated acoustic wave sensors.
Date: April 1, 1998
Creator: Hughes, R.C.; Yelton, W.G.; Ricco, A.J.; Patel, S.V.; Jenkins, M.W. & Eastman, M.P.
Partner: UNT Libraries Government Documents Department

Catalysts and process development for synthesis gas conversion to isobutylene. Quarterly report, July 1, 1991--September 30, 1991

Description: The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen-lean synthesis gas to isobutylene. The goals for this year were to recruit and organize the project team, complete the literature and patent searches, complete the management plan and other reporting requirements, complete the revision and upgrading of existing bench scale units for the project, and synthesize, characterize and evaluate the catalytic activity of zirconia prepared (1) by co-precipitation of zirconyl nitrate with ammonium hydroxide and (2) by preparing a hydrous zirconium oxide using the modified sol gel method developed at the Sandia National Laboratories followed by calcination. The same preparation procedure would be used to prepare supports for impregnation with thorium nitrate, a potassium salt and a sodium salt. The synthesis of new crystalline zirconates were to be attempted with the objective of producing new compositions of matter which might have higher activities and selectivities than zirconia. Substantial progress on reactor and kinetic models for slurry and trickle bed reactors was to be achieved. Accomplishments for the year are described.
Date: November 6, 1991
Creator: Anthony, R.G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994

Description: This project was initiated because the supply of isobutylene had been identified as a limitation on the production of methyl-t-butyl ether, a gasoline additive. Prior research on isobutylene synthesis had been at low conversion (less than 5%) or extremely high pressures (greater than 300 bars). The purpose of this research was to optimize the synthesis of a zirconia based catalyst, determine process conditions for producing isobutylene at pressures less than 100 bars, develop kinetic and reactor models, and simulate the performance of fixed bed, trickle bed and slurry flow reactors. A catalyst, reactor models and optimum operating conditions have been developed for producing isobutylene from coal derived synthesis gas. The operating conditions are much less severe than the reaction conditions developed by the Germans during and prior to WWII. The low conversion, i.e. CO conversion less than 15%, have been perceived to be undesirable for a commercial process. However, the exothermic nature of the reaction and the ability to remove heat from the reactor could limit the extent of conversion for a fixed bed reactor. Long residence times for trickle or slurry (bubble column) reactors could result in high CO conversion at the expense of reduced selectivities to iso C{sub 4} compounds. Economic studies based on a preliminary design, and a specific location will be required to determine the commercial feasibility of the process.
Date: March 1, 1995
Creator: Anthony, R.G.; Akgerman, A.; Philip, C.V.; Erkey, C.; Feng, Z.; Postula, W.S. et al.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, October 1, 1993--December 31, 1993

Description: The objectives of this project are to develop a new catalyst; the kinetics for this catalyst; reactor models for trickle bed, slurry and fixed bed reactors; and to simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. A hydrogen-lean synthesis gas with a ratio of H{sub 2}/CO of 0.5 to 1.0 is produced from the gasification of coal, lignite, or biomass. Isobutylene is a key reactant in the synthesis of methyl tertiary butyl ether (MTBE) and of isooctanes. MTBE and isooctanes are high octane fuels used to blend with low octane gasolines to raise the octane number required for modern automobiles. The production of these two key octane boosters is limited by the supply of isobutylene. MTBE, when used as an octane enhancer, also decreases the amount of pollutants emitted from the exhaust of an automobile engine.
Date: May 1, 1994
Creator: Anthony, R. G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 3, April 1, 1991--June 30, 1991

Description: The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butytl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; (2) addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and, (3) addition of methanol to slurry phase FT synthesis making iso-olefins.
Date: October 15, 1991
Creator: Marcelin, G.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Technical progress report No. 4, January 1, 1992--March 30, 1992

Description: The main goal of this contract is to develop a catalyst and technology that will produce iC{sub 4=} directly from coal-derived syngas and that is capable of using a lower H{sub 2}/CO ratio (0.5 to 1.0). The research will identify and optimize the key catalyst and process characteristics that give improved performance for CO conversion by a non-Fischer-Tropsch process. This report, which is the Technical Progress Report No. 4 for contract DE-AC22-91PC90042, covers the testing of various ZrO{sub 2}-based catalyst systems designed to examine the effects of catalyst preparation and process variables, especially the H{sub 2}/CO ratio. Testing of sol-gel ZrO{sub 2} catalysts with 1 or 2% cesium (Cs) addition indicates decreased stability at a H{sub 2}:CO ratio of 0.5. The addition of cobalt (Co) or copper (Cu) to the base ZrO{sub 2} catalyst results in a small activity gain, but a selectivity loss. This gain in Cu catalyst activity is mostly due to increased methane production. The Co catalyst shifts selectivity toward saturated products. The addition of water to the feed stream had a beneficial effect on stability. The addition of a basic clay had no effect on the activity or selectivity.
Date: September 10, 1993
Creator: Gajda, G. J.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report No. 2, June 15, 1991--September 30, 1991

Description: Gasoline reformulation has become a priority throughout the refining industry. In most proposed new gasoline formulations, the addition of oxygenates, such as methyl toruary butyl ether (MTBE), ethyl terfiary butyl other (ETBE), or teruary amyl methyl other (TAME), is being considered to maintain an acceptable octane. The production of the others MTBE and ETBE will ultimately be limited by the availability of isobutylene. Traditional commercial routes for producing isobutylene will be unable to meet the large growth in demand anticipated for fuel ethers. Developing a process in which coal could be converted to oxygenated gasoline blending components would take advantage of the vast coal reserves in the United States. The technology already exists for making methanol from coal-derived syngas. Numerous commercial processes are also available to make MTBE from methanol and isobutylene. A new technology that could be used to make isobutylene from syngas would complement the syngas-to-methanol process, and help to ease the anticipated shortages of isobutylene. The main goal of this contract Is to develop a catalyst and technology that will produce isobutylene directly from coal-derived syngas and that is capable of utilizing a lower (0.5 to 1.0) H{sub 2}:CO ratio. The research will identity and optimize the key catalyst and process characteristics that give improved performance for CO conversion by a non-Fischer-Tropsch process. This report, covers the testing of various Zro{sub 2}-based catalyst systems designed to examine the effects of catalyst preparation and process variables.
Date: October 3, 1991
Creator: Gajda, G. J.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly technical report No. 1, March 15, 1991--June 30, 1991

Description: The objective of this program is to develop an improved catalyst and process for the conversion of synthesis gas to isobutylene. The research will identify and optimize the key catalyst and process characteristics that give improved performance for CO conversion by a non-Fischer-Tropsch process.
Date: August 14, 1991
Creator: Gajda, G. J. & Barger, P. T.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Technical progress report No. 6, July 1, 1992--September 30, 1992

Description: Goal is to develop a catalyst and technology that will produce iC{sub 4}{double_bond} directly from coal-derived syngas and that is capable of using a lower H{sub 2}/CO ratio (0.5 to 1.0). This report covers the testing of various zirconia (ZrO{sub 2}) based catalyst systems designed to examine effects of catalyst preparation and process variables, especially feed additives. Testing sol-gel ZrO{sub 2} catalysts calcined at 475 C instead of 500 C increases the isobutene yield. Supporting zirconia on high-surface-area sol-gel silica or silica-alumina results in low activity catalysts. Addition of ethylene, propylene, ethanol to feed produces hydrogenation, dimerization, and metathesis products, but little or no isobutene.
Date: September 10, 1993
Creator: Gajda, G. J.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report number 19, October 1--December 31, 1995

Description: The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. After identification and optimization of key catalyst and process characteristics, the commercial potential of the process is to be evaluated by an economic analysis. From independent process variable studies to investigate the conversion of a methanol/ethanol feed to isobutanol, the best performance to date has been achieved with the 2% Pt on Zn/Mn/Zr oxide catalyst. Using Hyprotech Hysim v2.5 process simulation software, and considering both gas and liquid recycle loops in the process flow diagram, the overall carbon conversion is 98% with 22% selectivity to isobutanol. The expected production of isobutanol is 92 MT/day from 500 MT/day of methanol and 172 MT/day of ethanol feed. An additional 13 MT/day of isobutryaldehyde intermediate is recovered in the liquid product and vent streams. Because of the low selectivity (22%) of the methanol conversion catalyst to isobutanol, the process is uneconomical, even if the isobutanol is valued as a solvent ($903/MT) and not as isobutylene for MTBE production ($352/MT).
Date: July 1, 1996
Creator: Spehlmann, B.C.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly technical report No. 13, April 1, 1994--June 30, 1994

Description: The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. This report describes the preparation and testing of a variety of potential higher alcohols synthesis catalysts based on a bifunctional formulation consisting of a noble metal dehydrogenation function on a basic mixed metal oxide support. A pilot plant catalyst screening test using a 10/1 methanol/ethanol feed blend has been used to identify a new class of catalysts that afford higher selectivities and productivities. of the desired isobutanol and other C{sub 4+}, products than the Cu/Zn/Al oxide methanol synthesis catalyst that is being used as a baseline for this work. 2% Pd or Pt on a Zn/Mn/Zr oxide support and 2% Pd on a Zn/Mn/Cr support have given the best performances to date. In addition to isobutanol, these catalysts afford significant quantities of isobutyraldehyde and methyl isobutyrate. In order to elucidate the reaction pathway occurring with this class of catalyst, the 2%Pd on Zn/Mn/Zr oxide catalyst has been evaluated over a range of space velocities. It has been found that isobutanol and higher oxygenates yields increase with decreasing space velocity at ethanol conversions greater than 90%. This suggests that this catalyst is capable of converting methanol alone to higher alcohols. This is different from the result obtained with the Cu/Zn/Al oxide baseline catalyst, which showed no change in product yields at high ethanol conversions. Therefore, further effort will be focussed on the development of these noble metal/basic metal oxide catalysts for this application.
Date: December 31, 1994
Creator: Barger, P.T.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report No. 14, July 1, 1994--September 30, 1994

Description: The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. Previous work had identified Pt and Pd on Zn/Mn/Zr oxide and Pd on Zn/Mn/Cr oxide as promising catalysts for the conversion of a 10/1 methanol/ethanol blend to higher oxygenates. The reproducibility of these catalyst preparations has been found to be generally good, although some variations in performance have been observed between the Pd containing samples. Further characterization of the catalysts showing performance differences is in progress to determine whether compositional variations can account for the discrepancies. Several new 2% Pt on metal oxide catalysts have been prepared and tested. None of these materials performed better than the original 2% Pt on Zn/Mn/Zr (34/34/32 molar) oxide catalyst. However, a lower Zr content support (45/45/10 Zn/Mn/Zr oxide) gave similar results. Evaluation of the 2% Pd on Zn/Mn/Cr oxide at high space velocities has indicated that this material may be substantially less active for the C{sub 1}{minus}C{sub 1}, condensation step necessary for methanol only conversion to higher alcohols. In view of this finding, subsequent research will focus on the development of the Zn/Mn/Zr oxide support. A variety of alternative catalyst formulations have also been prepared and tested, but have failed to match the performance of noble metal on mixed metal oxide catalysts. These materials have include Cu and Mo on TiO{sub 2}, Mg/Al MOSS and polyvinylpyridine and commercial and laboratory prepared Mn oxide samples.
Date: December 31, 1994
Creator: Barger, P.T. & Kurek, P.R.
Partner: UNT Libraries Government Documents Department

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly technical report No. 12, January 1, 1994--March 31, 1994

Description: The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. This report describes pilot plant testing using a 10/1 methanol/ethanol feed blend to identify potential catalysts for the conversion of lower alcohols derived from synthesis gas to isobutanol and other C{sub 4+} oxygenates. The previous work in this project found that a typical Cu/Zn/Al oxide methanol synthesis catalyst is capable of producing isobutanol and isobutryaldehyde from a feed consisting of a blend of methanol and ethanol. Best performance was obtained at moderate temperature (300 {degree}C) and low pressure (30 psig). This report describes the results of space velocity testing with this catalyst to elucidate the reaction pathway. It has been found that at high ethanol conversion levels (low space velocities), yields of isobutanol and other C{sub 4+} oxygenates do not increase with increasing methanol conversion. This suggests that Cu/Zn/Al oxide is not active for the condensation of methanol alone to higher alcohols. Therefore, new catalyst formulations are being evaluated for this reaction using the Cu/Zn/Al oxide performance as a baseline. Promising materials will also be examined at high ethanol conversion levels and with a methanol only feed to determine their capability to condense methanol.
Date: April 1, 1995
Creator: Barger, P.T.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, January 1, 1993--March 31, 1993

Description: The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed reactors, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. The six main accomplishments for the quarter are the following: (1) activity testing with the 7% (wt) Ce-ZrO{sub 2}, (2) activity testing the same catalyst with CO from an aluminum cylinder, (3) preparation of ZrO{sub 2} by heating zirconyl nitrate, (4) preparation of an active zirconia prepared by a modified sol gel procedure and evaluation of the catalytic activity of a commercial zirconia and the catalysts prepared by the sol gel procedure, (5) determining the effect of separator temperatures and oil flow rate on the performance of a trickle bed reactor, and (6) calculation of the equilibrium composition of the C{sub 2} to C{sub 5} olefins, and initiation of the development of a macrokinetic model. The details of each of these accomplishments are discussed.
Date: April 17, 1993
Creator: Anthony, R.G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Dehydration of isobutanol to isobutene in a slurry reactor

Description: The April 1990 Alternative Fuels Proposal to the Department of Energy involved the development of new technology, based on the liquid phase process, for conversion of coal-derived synthesis gas to oxygenated hydrocarbon fuels, fuel additives, and fuel intermediates. The objective of this work was to develop a slurry reactor based process for the dehydration of isobutanol to isobutene. The isobutene can serve as a feedstock for the high octane oxygenated fuel additive methyl tertiary-butyl either (MTBE). Alumina catalysts were investigated because of their wide use as a dehydration catalyst. Four commercially available alumina catalysts (Catapal B, Versal B, Versal GH, and Al-3996R) were evaluated for both activity and selectivity to the branched olefin. All four catalysts demonstrated conversions greater than 80% at 290 C, while conversions of near 100% could be obtained at 330 C. The reaction favors low pressures and moderate to low space velocities. A yield of 0.90 mole isobutene per mole reacted isobutanol or better was obtained at conversions of 60--70% and higher. From 75 to 98% conversion, the four catalysts all provide isobutene yields ranging from 0.92 to 0.94 with the maximum occurring around 90% conversion. At low conversions, the concentration of diisobutyl ether becomes significant while the concentration of linear butenes is essentially a linear function of isobutanol conversion. Doping the catalyst with up to 0.8 wt % potassium showed a modest increase in isobutene selectivity; however, this increase was more than offset by a reduction in activity. Investigations using a mixed alcohols feed (consistent with isobutanol synthesis from syngas) demonstrated a small increase in the C4 iso-olefin selectivity over that observed for a pure isobutanol feed. 55 refs.
Date: February 1, 1994
Creator: Latshaw, B.E.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, April 1, 1992--June 30, 1992

Description: A rate equation for carbon monoxide consumption showing first order in CO and 0.5 order in hydrogen indicates the rate controlling step involves dissociated hydrogen. The inhibition of the rate with carbon dioxide is also shown. Examination of the hydrocarbon distributions indicates a see-saw effect with the C{sub 4}s representing the fulcrum and methane and C{sub 5}{sup +} the end points. The shift in the distributions tends to be towards the C{sub 5}{sup +} for high pressures and long residence times. This distribution can be shifted by incorporating Ti into the catalysts, but the optimum amount of Ti needs to be determined. The sol gel method of preparing the catalysts tends to produce a less active catalyst than by precipitation of a zirconyl salt. The most active catalyst contained approximately 2% Th/ZrO{sub 2}
Date: July 27, 1992
Creator: Anthony, R. G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, July 1, 1993--September 30, 1993

Description: Trickle bed reactor experiments using precipitated and commercial zirconia resulted in the production of more C{sub 2}-C{sub 3} hydrocarbons than the fixed bed gas phase reactor when using a hydrogen to CO ratio of 1. Because of problems associated with solvent cracking the reactor temperature for the trickle bed was limited to 400{degrees}C, whereas temperatures up to 450{degrees}C had been used for the fixed bed reactors. Co-feeding H{sub 2}S with the synthesis gas resulted in reduction of C{sub 1} to C{sub 3} production rates, an increase in C{sub 5} production and an increase in the production of 3-methyl-l-butene. Zirconia prepared with Ce resulted in a highly active and selective catalyst with isobutylene production rates of 4 to 8.5 kg/(m{sup 3} cat. h) for CO conversions of 15 to 34%. Kinetic models necessary for reactor design are first order for CO and one half order for hydrogen, indicating the dissociation of hydrogen on the catalyst surface. Carbon dioxide was found to be the most abundant specie on the surface of the catalyst and retards the rate of reaction. A modification of the Anderson Schultz Flory distribution resulted in an empirical procedure for estimating product distributions.
Date: November 23, 1993
Creator: Anthony, R. G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department

Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, January 1, 1992--March 31, 1992

Description: The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene.
Date: May 26, 1992
Creator: Anthony, R. G. & Akgerman, A.
Partner: UNT Libraries Government Documents Department