Fischer-Tropsch Type Research Articles

Laboratory Studies of Catalysis of CO to Organics on Grain Analogs

Experiments simulating heterogeneous conversion of H 2 and CO into simple hydrocarbons in astrophysical environments have been performed, utilizing realistic cosmic grain analogs of Fe-doped silicates as Fischer–Tropsch-Type catalysts. Catalysis was studied for temperatures from 470–670 K and reactant gas mixtures of H 2/CO with a ratio of 2–100. The total gas pressure was near 0.5 bar. Maximum conversion rates of a few percentage points were achieved over a 3-h time period. Major products were methane, ethane, ethylene, carbon dioxide, and water. Products were identified by IR spectroscopy.

The role of fluids during formation and evolution of the southern Superior Province lithosphere: an overview

Models for fluid flow and hydrothermal alteration for the Abitibi greenstone belt are reviewed in the light of Lithoprobe results in the region. In the Abitibi greenstone belt, eruption of volcanic sequences over 2750-2700 Ma was accompanied by pervasive low-temperature hydrothermal alteration at high water/rock ratios, giving systematic 18O-enrichment. Archean ambient ocean water bottom temperatures were likely ca. 30°C, and δ18O ~0 ± 1‰. Chert-iron formations precipitated from low temperature hydrothermal discharge. Base metal massive sulphide deposits formed at or near the seafloor from focussed discharge of high-temperature (~300-400°C) fluids in convective cells sited above subvolcanic intrusions. The ore fluids were evolved seawater that had undergone compositional and isotopic evolution by high-temperature, low water/rock exchange with the volcanic pile to NaCl (3-7 wt.%) or CaCl2-NaCl (up to 30 wt.%) brines of δ18O = 0-8‰. These volcanic associated hydrothermal deposits are associated with greenstone belt asemblages in the northern Abitibi subprovince that were emplaced as a series of thrust slices over the Opatica plutonic belt. In the southern Abitibi subprovince the hydrothermal deposits were associated with a series of rift basins (Noranda, Val d'Or, etc.), formed on top of accreted oceanic assemblages comprising primitive arcs and plateaus, or in protoarcs, and associated with oblique convergence. Contemporaneous erosion of emergent arcs and the older cratonic provenance terrane of the Pontiac subprovince by orographic rainfall, and submarine weathering, fed first-cycle vol cano genic sediments to depositional basins in the Abitibi, but siliciclastic sediments of mixed old 3 Ga continent and 2.7 Ga arc provenance in the Pontiac subprovince. Abitibi subprovince turbidites were more weathered and 18O-enriched than Pontiac subprovince equivalents. Subduction-accretion assembly of the Opatica-Abitibi and Pontiac terranes involved allochthonous thrusting of the Abitibi subprovince over the Pontiac subprovince. There were several pulses of granitoid magmatism during accretionary assembly over 2695 to 2674 Ma. Syn- to late-tectonic tonalites were generated by melting of hot young hydrous ocean crust in a shallow-dipping intraoceanic subduction zone. The intrusions exsolved small quantities of magmatic fluids that formed Cu-Zn showings. Late-tectonic shoshonites formed at [Formula: see text]80 km in subarc mantle wedge by slab dehydration-wedge melting. This late-stage of arc development involved transfer of significant quantities of gas-rich alkaline magmas 80+ km through the lithosphere along the accretionary terrane bounding structures, and produced small phosphorus and barite deposits. Synmagmatic metamorphism was of the high-temperature low-pressure type, and occurred in several pulses; water/rock ratios were generally low distal from structures. Tens of thousands of cubic kilometres of fluids generated by dehydration reactions at the base of the subduction-accretion complex, during thermal relaxation following collision and the main granitoid pulses, advected up terrane boundary structures and locally generated lode gold deposits. At the highest structural levels these fluids mixed with Archean meteoric water where δ18O < 0. A second metamorphism (M2) occurred over 2645 to 2611 Ma leading to melting of Pontiac sediments and formation of S-type granites. Deposits of Mo, Th, and P were precipitated from magmatic fluids of δ18O 8-9‰. M2 variably reset radiogenic and stable isotope systems in nonrobust minerals of vol canogenic massive sulphide and lode gold deposits. Hypersaline CaCl2 formation brines evolved in Paleoproterozoic glaciogenic sediments; these penetrated into the Archean basement where they redistributed gold and are pervasively present as low-temperature secondary brine inclusions. The Matachewan (2.5 Ga) and Hearst dyke swarms drove higher temperature advection of the brines, and Ag-Co-Ni sulpharsenide deposits formed by thermal evolution of the brines driven by the Nipissing diabase dyke swarm at ~2219 Ma. Local resetting of 40Ar/39Ar spectra between 2550 and 2200 Ma was the product of tectonic pumping of fluids along reactivated Archean structures, possibly due to coupling of the 200 km thick mantle lithosphere to Archean crust. Seismic evidence for late overprinting of the lower crust and growth of 2450 Ma zircon rims in lower crustal assemblages were associated with this event. There was also fluid activity at 1950 to 1850 Ma due to the Hudsonian orogen induced Kapuskasing event. Hypersaline CaCl2-rich brines formed in the Paleozoic sedimentary cover (~500 Ma), penetrated deep (>5 km) into the Archean basement, and comprise vast reservoirs of hypersaline brines deep in the Shield. The brines precipitated prehnite-laumontite veins that record hundreds of increments of dilation. Subglacial 18O-depleted fluids penetrated to shallow ([Formula: see text]1 km) depths in the Quaternary; they form mixing lines with the hypersaline end member. Extremely D-depleted (-400 to -100‰) CH4 and H discharge in mining districts of the Shield. The depleted H may form by radiolysis of H2O and (or) by a Fischer-Tropsch type process. The hypersaline brine end-member was shifted to the left of the meteoric water line by exchange with D-depleted H.

Comparative study of Fischer–Tropsch synthesis with H 2/CO and H 2/CO 2 syngas using Fe- and Co-based catalysts

Hydrogenation of CO, CO 2 and their mixtures has been comparatively studied with a Co–MnO–Aerosil–Pt and a Fe–Al 2O 3–Cu–K catalyst at the University of Karlsruhe. With iron catalysts as promising for CO 2 hydrogenation, their composition was varied: (1) several supports (SiO 2, TiO 2, Al 2O 3), (2) alkali promotion (Li, Na, K, Rb), (3) usage of Zeolite Y as catalyst component. The catalysts were characterised by adsorption methods, XRD, TPR and temperature programmed decarburisation after a H 2/CO 2 treatment (Korea Research Institute of Chemical Technology). Iron and cobalt catalysts behaved differently in CO 2 hydrogenation. With the alkalised iron catalyst the same hydrocarbon product composition was obtained from a H 2/CO 2 and from a H 2/CO synthesis gas in spite of the CO partial pressure remaining low, specifically due to water gas shift equilibrium constraints. With the cobalt catalyst at increasing CO 2 and respectively decreasing CO content of the syngas, the product composition shifted from a Fischer–Tropsch type (mainly higher hydrocarbons) to almost exclusively methane. These basically different catalyst behaviours are explained by different modes of formation of the kinetic regime of FT synthesis—selective inhibition of methane formation and the selective inhibition of product desorption as a prerequisite for chain growth—in the case of iron through irreversible carbiding and alkali surface coverage and in case of cobalt through strong reversible CO adsorption. Investigation of the various modified iron catalysts showed alumina to be the best support for CO 2 hydrogenation and potassium to act as a powerful promotor. With the Fe–Y–zeolite–alkali catalysts, a decrease of methane selectivity was observed in the order Li < Na < K < Rb being applied as promotors.

Serpentinization of oceanic crust and Fischer-Tropsch type synthesis of organic compounds

Serpentinization of oceanic crust and Fischer-Tropsch type synthesis of organic compounds

95/00140 Chemical molecular and isotopic differentiation of organic facies in the Tertiary lacustrine Duaringa oil shale deposit, Queensland, Australia

The genetic identification of different types of natural gas is notably important for assessment of its sources and exploration potential. The chemical and isotopic (C and H, in particular) compositions of natural gas vary significantly due to the complexity of its generation, migration, and accumulation processes. The “coal-type” gas generated from humic matter is generally enriched in 13C as compared to "oil-type" gas generated from sapropelic organic matter. However, gas originating from fresh-brackish water environments is depleted in 13C whereas gas from saline environments is enriched in 13C. Notwithstanding organic precusors and sedimentary environments, both isotope compositions of alkanes tend to become enriched both in 13C and 2H with prograde thermal evolution. Therefore, in addition to thermal maturity, source material is the major controlling factor of carbon isotope compositions, whereas sedimentary environment is predominant in governing hydrogen isotopes. Secondary processes, including thermochemical sulfate reduction (TSR) and diffusion, result in an enrichment of the gases in 13C and 2H due to mass-dependent kinetic isotope effect. Microbial degradation causes a decrease in propane content and an enrichment in 12C and 2H of the residual propane. The abiogenic gases may include methane from deep mantle and high molecular weight hydrocarbons through Fischer-Tropsch type (FTT) synthesis. Methane of mantle origin possesses a narrow range of isotope compositions, although it is still a tall task to determine the exact values. In contrast, isotopes of alkane gases synthesized from FTT processes are in a wide range. In sedimentary basins, the mixing of gases from multiple sources and/or through different secondary processes may pose a challenage to identification of their origins. The detailed assessment is provided here with case studies from major oil and gas basins in China. This review provides identification of misconceptions in genetic types of natural gas using carbon and hydrogen isotopes of alkanes, and sheds insights into using isotope geochemistry as an important diagnostic tool for energy exploration as well.

Mantle hydrocarbons: Abiotic or biotic?

Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) and peridotite xenoliths in alkali basalts contain heavier hydrocarbons ( n-alkanes), whereas igneous rocks produced by magmas such as gabbro and granite lack them. The occurrence of hydrocarbons indicates that they were not derived either from laboratory contamination or from field contamination; these compounds found in the mantle-derived rocks are called here “mantle hydrocarbons.” The existence of hydrocarbons correlates with petrogenesis. For example, peridotite cumulates produced by magmatic differentiation lack hydrocarbons whereas peridotite xenoliths derived from the mantle contain them. Gas Chromatographic—mass spectrometric records of the mantle hydrocarbons resemble those of aliphatics in meteorites and in petroleum. Features of the hydrocarbons are that 1. (a) the mantle hydrocarbons reside mainly along grain boundaries and in fluid inclusions of minerals 2. (b) heavier isoprenoids such as pristane and phytane are present 3. (c) δ 13 C of the mantle hydrocarbons is uniform (about −27%.). Possible origins for the mantle hydrocarbons are as follows. 1. (1) They were inorganically synthesized by Fischer-Tropsch type reaction in the mantle. 2. (2) They were delivered by meteorites and comets to the early Earth. 3. (3) They were recycled by subduction. The mantle hydrocarbons in the cases of (1) and (2) are abiogenic and those in (3) are mainly biogenic. It appears that hydrocarbons may survive high pressures and temperatures in the mantle, but they are decomposed into lighter hydrocarbon gases such as CH 4 at lower pressures when magmas intrude into the crust; consequently, peridotite cumulates do not contain heavier hydrocarbons but possess hydrocarbon gases up to C 4H 10.

Carbonylation of BH-boranes; evidence for a Fischer—Tropsch type reaction

Bis(9 H-9-borabicyclo[3.3.1]nonane) is readily carbonylated under about 50 bar pressure of carbon monoxide at 100°C. Bis(1,5-cyclooctanediyl)-2,5-dibora-1,4-dioxane ( 1a) is formed quantitatively. Reaction of 1a at room temperature with acetic or propionic acid affords the corresponding 9,10-diacyloxy-bicyclo[3.3.2]decanes 2a and 2b. Thermolysis of 1a gives the tris-(5-cyclononenyl-boroxine 4 as the main product. The expected tris(bicyclo[3.3.1]nonanylboroxine) 3 in formed only in a side reaction. The carbonylation of tetraethyldiborane(6) is easier, requiring about 10–20 bar of carbon monoxide pressure at room temperature. The product consists of a mixture of 2,5-dibora-1,4-dioxanes with partially homologated alkyl substituents. The homologation proceeds in a manner analogous to that of the Fischer-Tropsch reaction.

Chemical markers of prebiotic chemistry in hydrothermal systems.

The goal of this chapter is to suggest some organic compounds which may be indicative of prebiotic processes in hydrothermal systems or laboratory simulations of them. While the exact processes which led to the origins of life are not known, studies of life's origins of the past forty years have uncovered a plethora of potential precursor molecules. Some of these same molecules were probably present in hydrothermal systems if chemical processes there had a role in the origins of life. The types of molecules formed in primitive Earth simulation experiments and observed in the interstellar medium, on comets and meteorites will be reviewed in Section 2 of this chapter. Some reactions involving these molecules which may have been important in prebiotic syntheses will be outlined. Since near- to supercritical water is found in hydrothermal systems, its properties and aspects of organic chemistry in supercritical water at high temperature and pressure will be discussed in Section 3. Fischer-Tropsch type (FTT) reactions, which are a potential source of the building blocks of biological molecules in hydrothermal systems, are discussed in Section 4. In the concluding section, Section 5, the possible formation in hydrothermal systems of organic molecules that are believed to have been important for the origins of life is discussed.

Preparation of Rh‐containing cellulose acetate films and the chemistry of Rh in cellulose acetate

AbstractRhCl [P(C6H5)3]3 complexes have been incorporated in cellulose acetate as a dispersion medium using cosolvent (tetrahydrofuran). The interactions between Rh (I) complexes and cellulose acetate (CA) are examined by infrared spectroscopy and thermal analysis. The chemical reactivities of Rh–CA films have been investigated by reacting Rh sites with CO, H2, O2, and C2H4 in the temperature range 90–150°C and at a pressure of less than 1 atm. Three different Rh‐carbonyls and a Rh‐hydride species formed in CA are characterized by their infrared spectra. Treatment of 10 or 20 wt % Rh–CA films with hydrogen (600 torr) at 150°C produces small Rh metal particles of ca. 10 Å or less in diameter in CA, which show catalytic activities under mild conditions in various reactions such as hydrogenation of C2H4, oxidation of CO, and Fischer–Tropsch type reactions.

Developing molecular Fischer-Tropsch type chemistry: the triethylboron-catalyzed oligomerization of carbon monoxide-derived methylene groups from a (.eta.2-formaldehyde)zirconocene dimer

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDeveloping molecular Fischer-Tropsch type chemistry: the triethylboron-catalyzed oligomerization of carbon monoxide-derived methylene groups from a (.eta.2-formaldehyde)zirconocene dimerGerhard Erker, Stefanie Schmuck, and Ursula HoffmannCite this: J. Am. Chem. Soc. 1991, 113, 6, 2330–2332Publication Date (Print):March 1, 1991Publication History Published online1 May 2002Published inissue 1 March 1991https://doi.org/10.1021/ja00006a077RIGHTS & PERMISSIONSArticle Views128Altmetric-Citations14LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (392 KB) Get e-Alerts Get e-Alerts

Carbon-rich aggregates in type 3 ordinary chondrites: Characterization, origins, and thermal history

Carbon-rich aggregates from 3 type 3.4–3.6 ordinary chondrites and 2 chondritic clasts have been characterized in detail using transmission electron microscope techniques. The aggregates in all the meteorites studied range in size from 5–1000μm and consist of a fine scale intergrowth of poorly graphitized carbon, amorphous carbon, Fe,Ni metal, and minor chromite. Contrary to previous reports, well-crystallized graphite and magnetite are absent. The association of Fe,Ni metal and carbonaceous material suggests that the original carbonaceous material may have formed by Fischer-Tropsch (FT) type reactions (catalytic hydrogenation of CO gas) at low temperatures (< 400 K), possibly in the solar nebula. This carbonaceous material probably consisted of a complex mixture of hydrocarbons, kerogen-like material, and other complex organic molecules. The aggregates were subsequently accreted onto the ordinary chondrite parent bodies and underwent planetary thermal processing which resulted in the catalytic graphitization of hydrocarbons, in the presence of Fe,Ni metal, to produce poorly graphitized carbon. None of the meteorites studied experienced temperatures sufficiently high to produce crystalline, ordered graphite. Using the empirical geothermometer of Rietmeijer and MacKinnon (1985), the measured d 002 spacings of poorly graphitized carbon show that graphitization occurred at temperatures between 300 and 450°C. This range of temperatures is significantly lower than the generally quoted metamorphic temperatures for type 3.4–3.6 ordinary chondrites (∼450–500°C; Dodd, 1981). The presence of poorly graphitized carbon in type 3 ordinary chondrites is also clear evidence that these chondrites must have accreted cold: no carbonaceous material would have been present in these meteorites if they had accreted at high temperature (> 1000 K). Although it is possible that some of the carbon in the type 3 ordinary chondrites could have been produced by recondensation of CO produced by outgassing from a planetesimal interior, evidence for such an origin for the C-rich aggregates is not compelling.

Boron hydride insertion into the ZrC bond of dimeric (η 2-formaldehyde)zirconocene

Insertion of borohydride into the metallaoxirane ZrC bond takes place upon treatment of the (η 2-formaldehyde)zirconocene dimer 2 with 9-borabicyclo[3.3.1]nonane. The resulting metallacyclic dimer [Cp 2 ZrOCH 2B(C 8H 14)H ] 2 ( 4) has been characterized by X-ray diffraction. Complex 4 is a model for an intermediate stage of the insertion of CO-derived methylene groups into metalhydrogen bonds, such as is thought to occur in Fischer-Tropsch type processes.

The chemistry of ruthenium in PSSA lonomer: Reactions of Ru-PSSA with CO, H 2, O 2, and alcohols

Ru(III) ions have been incorporated in the domains of sulfonated linear polystyrene (PSSA) as a dispersion medium to form PSSA-Ru(III) films through an ion-exchange process. The chemical reactivities of PSSA-Ru(III) films have been investigated by reacting the ruthenium sites with CO, H 2, O 2, CH 3OH, and C 2H 5OH under mud conditions. The reactions of PSSA-Ru(III) films with CO (400 Torr) in the temperature range 25–186 °C resulted in four different Ru carbonyl species, which were characterized by their infrared spectra. Treatment of PSSA-Ru(III) films with hydrogen (400 Torr) at 150 °C produced ruthenium hydride species, which were confirmed by identifying the corresponding ruthenium deutendes. Also, HD exchange on benzene rings of the polystyrene backbone was found to occur during the reaction of PSSA-Ru(III) films with D 2. The reactions of aqueous methanol and ethanol with PSSA-Ru(III) films produced ruthenium carbonyl species, but there was no evidence of the formation of ruthenium hydride or ruthenium formyl groups in the infrared spectra. Static Fischer-Tropsch type reactions of PSSA-Ru(III) powder with CO (300 Torr) and H 2 (300 Torr) at 150 °C showed the formation of various aliphatic hydrocarbons, oxygen-containing hydrocarbon compounds, and CO 2 in the mass and infrared spectra.

The prediction of the performance of simple catalytic reactors for Fischer-Tropsch type catalytic polymerization reactions

Kinetic equations based on the Schultz-Flory theory and simple power law kinetics for the product distributions are used in a special class of catalytic polymerization reactions of which Fischer-Tropsch reactions form a sub-class. These kinetic equations are tested using selectivities obtained from the literature and at SASOL. The equations are mathematically tractable and allow the integration of the material balance equations in isothermal reactors. The result is a fairly simple model which may be used in the design and characterization of such reactors.

Dehydration of alcohols on iron Fischer-Tropsch type catalysts

The dehydration of 1-butanol was studied on iron Fischer-Tropsch type catalysts. Chemical trapping allowed us to propose a mechanism involving hydrogenolysis of the C−O bond with the selective formation of 1-butene.

Methane Synthesis on Nickel by a Solid-State Ionic Method

The feasibility of electrochemically synthesizing methane by a Fischer-Tropsch type reaction by use of a solid oxide electrolyte has been demonstrated. This solid-state ionic approach provides in situ control of the oxygen activity at the gascatalyst interface by imposing a suitable voltage drop across an oxygen-conducting solid electrolyte from an external source. Methanation rates for hydrogen-carbon monoxide and hydrogen-carbon dioxide synthesis gas mixtures upon nickel electrodes showed substantial enhancement with the use of this technique, reaching values nearly two orders of magnitude higher than their intrinsic rates.

Basic nitrogen-heterocyclic compounds in the Murchison meteorite

A fragment of the Murchison (C2) carbonaceous meteorite was analyzed for basic, N- heterocyclic compounds, by dual detector capillary gas chromatography as well as capillary gas chromatography/mass spectrometry, using two columns of different polarity. In the formic acid extract 2,4,6-trimethylpyridine, quinoline, isoquinoline, 2-methylquinoline and 4-methylquinoline were positively identified. In addition, a suite of alkylpyridines and quinolines and/or isoquinolines was tentatively identified from their mass spectra. The (iso)quinolines were found to contain methyl substituents exclusively. The distribution of the pyridines observed reveals a similarity to that observed from catalytic reactions of ammonia and simple aldehydes under conditions similar to those applied in Fischer-Tropsch type reactions.

Mechanistic approaches and high pressure homogeneous hydrogenation of carbon monoxide

In order to gain better understanding of the mechanistic pathway leading to chain propagation and termination in Fischer-Tropsch type reactions, complexes with sp 3-and sp 2-hybridized carbon-metal bonds were reacted with carbon monoxide and mixtures of hydrogen and carbon monoxide. In all our experiments only the insertion of one CO was observed. The second part of this paper deals with homogeneous hydrogenation of carbon monoxide at high pressures. Clusters and complexes of Group VIII elements of the Periodic Table were used as catalysts. A variety of oxygenated compounds such as methyl formate, methyl acetate, ethyl formate, methanol, ethanol, n-propyl alcohol, propylene glycols, ethylene glycol and glycerine was formed to varying degrees. The mechanism of the cobalt catalyzed reactions is discussed and non-cluster but bimetallic intermediates are proposed for the key steps.

Nitrogen-heterocyclic compounds in meteorites: significance and mechanisms of formation

Samples of the Murchison (C2), Murray (C2) and Orgueil (C1) carbonaceous meteorites were analyzed for nitrogen-heterocyclic compounds using gas chromatography, cation and anion exclusion liquid chromatography and mass spectrometry. The purines adenine, guanine, hypoxanthine and xanthine were identified in formic acid extracts of all samples, in concentrations ranging from 114–655 ppb. Purines have not previously been found in the Murray meteorite and adenine. hypoxanthine and xanthine have never simultaneously been detected in meteorite extracts. All four biologically significant purines, as well as the pyrimidine uracil have now been identified in these meteorites. A number of other, previously reported N-heterocyclic compounds such as certain hydroxypyrimidines and s-triazines could not be detected in any of the extracts. Laboratory data indicated that both these classes of compounds may be formed from structurally simple precursors (such as guanylurea in the case of s-triazines) during the extraction and analysis of meteorite extracts. We find that the suite of N-heterocyclic compounds identified in meteorites do not, at present, permit a clear distinction to be made between mechanisms of synthesis such as the Fischer-Tropsch type and other candidates. Secondary reactions and conversions in meteorite parent bodies, of HCN and other nitriles produced by Miller-Urey type reactions as well as by Fischer-Tropsch type reactions, must also be considered.

Phenolic Ethers in the Organic Polymer of the Murchison Meteorite

Seven phenolic acids and many nonphenolic organic acids, including large amounts of meta-hydroxy (3-hydroxy) benzoic acid and 3-hydroxy-1,5-benzene-dicarboxylic acid, were obtained from the organic polymer of the Murchison C2 chondrite upon oxidation with alkaline cupric oxide. The phenolic acids apparently were derived from phenolic ethers in the polymer, which in turn probably were formed from carbon monoxide and hydrogen by catalytic Fischer-Tropsch type reactions in the solar nebula. In contrast, terrestrial polymers such as lignin, humic acid, and coal yield mainly para-hydroxy (4-hydroxy) benzene derivatives by the same oxidation procedure.