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The structure of vanadium oxide overlayers of V2O5/SiO2 catalysts prepared by chemical vapour deposition (CVD) and impregnation methods has been determined by using vanadium K-edge EXAFS and XANES. The Fourier transform of EXAFS for the vanadium oxide overlayers obtained by CVD of VO(OC2H5)3 showed very weak peaks due to V—O—V bonds, even at the high loading level of V2O5(17 wt.%), while crystalline V2O5 gave strong peaks due to V—O and V—O—V bonds. On the basis of the EXAFS and XANES results, it has been concluded that the vanadium oxides obtained by the CVD method were present as thin overlayers on SiO2, and were stable to calcination at 773 K. On the other hand, with an impregnation method, XANES of V2O5/SiO2 at loading levels less than 5 wt.% gave peaks different from those of crystalline V2O5. It was presumed that an isolated V species was formed as reported in the literature. At loading levels >5 wt.%, XANES and EXAFS for V2O5/SiO2 catalysts prepared by the impregnation method were very similar to those of crystalline V2O5, indicating that crystallites of V2O5were formed on SiO2 in this case. This occurs because aggregates of vanadium compounds, e.g. oxalate, were formed as precursors of V2O5 during the drying process.

In the present study, X-ray absorption fine structure (XAFS) analyses (extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES)) have been used to obtain a better understanding of the support effects on the structure of the calcined catalysts. In particular, the focus of the discussion is on the coordination symmetry around Mo, since the EXAFS techniques gives direct information on the local structure aroud specific atoms.

Molybdate, nickel-molybdate and cobalt-molybdate/γ-alumina catalysts were prepared by an impregnation method using citric acid as well as ammonia as ligands. Molybdenum structures in the impregnating solutions and on the sulfided catalysts were characterized by EXAFS and XPS. Agglomerated molybdenum octahedra existed in the impregnating solutions containing citric acid, in contrast to the monomeric molybdenum tetrahedra obtained when using ammonia. The nickel-molybdenum catalyst prepared by using citric acid was inferior to the one prepared by using ammonia in terms of both hydrogenation and HDN activities, which might be due to a decrease in the amount of active Ni-Mo-S phase. On the other hand, the cobalt-molybdenum catalyst prepared using citric acid was superior to the one prepared using ammonia in terms of HDS activity. A decrease in the lateral size of MoS 2 -like crystallites might attribute to an increase in the HDS activity.

The temperature-programmed oxidation of sulfided cobalt-molybdate, molybdate, and cobalt catalysts was carried out in a thermogravimetric reactor equipped with a differential thermal analyzer and a fixed-bed reactor equipped with a mass spectrometer. Attempts were made to elucidate changes in chemical states of supported metals and in sulfur forms during oxidation using X-ray photoelectron spectroscopy (XPS) and extended X-ray adsorption fine structure (EXAFS). The thermodynamics of sulfide transformation into oxides and sulfates was investigated

Nickel-molybdate and cobalt-molybdate catalysts were used for hydrotreating coal-derived oils and a petroleum vacuum gas oil. The metallic components deposited on the spent catalysts were characterized to reveal their inhibitory effects on hydrogenation and hydrocracking activities. Inhibition by typical metal components, such as Na, K, Mg, Ca, Fe, Ti, Ni and V, were also evaluated by doping such metals on the catalysts. Inhibitory effects of alkali and alkaline earth metals on hydrogenation and hydrocracking activities were significant, and their effects decreased in the following order for both catalytic activities; KNaCaMg. Deposition of V, Fe and Ti resulted in an increase in hydrocracking, but a decrease in hydrogenation. The effect of these metals decreased in the following order: VFeTi. Data from X-ray photoelectron spectroscopy, X-ray diffraction and extended X-ray absorption fine structure showed that alkali and alkaline earth metals not only segregated on the catalyst surface to cover the active sites but also caused the lateral growth of MoS 2 -like structures, and that some of these metals formed double oxides with molybdenum after the oxidative regeneration. The neutralization of acidity was significant for these basic metals. On the other hand, V, Fe and Ti tended not only to disperse the MoS 2 -like species but also to increase the catalyst acidity through the formation of an acidic double oxide with molybdenum/alumina support.

The influences of oxygen-containing compounds on the changes in chemical states of sulfided metals in molybdate catalysts during the hydrotreatment of hydrocarbon feedstocks were investigated. The effect of oxygen-containing model compounds on the deactivation in the hydrodenitrogenation (HDN) activity of NiMo catalyst in hydrotreating a subbituminous coal-derived kerosine oil was in the order of O2 H2O2 > benzofuran > phenol > H2O. The XPS analyses of the heavily deactivated NiMo catalysts in the presence of oxygen-containing model compounds showed that the amounts of Mo4+ decreased significantly, and almost all of nickel sulfide and sulfidic sulfur were converted into Ni2+ and sulfate sulfur, respectively. The pre-oxidation of the sulfided NiMo catalyst via air, i.e. the formation of metal sulfides into oxides/sulfates, resulted in a decrease in HDN activity. The higher the degree of oxidation was, the lower the HDN activity was. It was suggested that some amounts of metal sulfides were converted into the lower reactive oxides/sulfates via oxygen in the oxygen-containing compounds even under hydrotreating conditions.

Temperature-programmed oxidation of nickel-molybdate, molybdate and nickel catalysts was carried out in thermogravimetric and fixed bed reactors. During the oxidation of sulfided NiMo catalyst in air, the SO2 formation exhibited three maxima at about 433, 530 and 693 K, and about 11% of the total amount of sulfur remained after oxidation at 773 K. The SO2 formation for sulfided molybdenum and nickel catalysts indicated that the first and second maxima might be mainly from oxidation of nickel sulfide and MoS2-like sulfides, respectively. The promotion of nickel in molybdate catalysts resulted in an increase in the amount of residual sulfur, mainly as sulfate, after oxidation. The formation of nickel sulfate was inferred from thermodynamic data. XPS data revealed that the formation of the third SO2 maximum, accompanied by an exothermic reaction, might mainly result from oxidation of the unoxidized MoS2-like sulfides (Mo4+) and nickel sulfides remained in the bulk of the supported metals. The amount of residual sulfur could be reduced by decreasing the amount of oxygen in the oxidizing agent. A thermodynamic investigation supported this result.

石炭液化油の水素化処理反応において使用されるNi-Mo/Al2O3触媒の活性低下挙動を明らかにするために, 反応水素圧および原料油中のプレアスファルテン含有量を変化させて, それぞれ2,000時間反応を行った。その結果, 原料油中のプレアスファルテンの含有量が多い場合は, 触媒の水素化活性の低下が大きく, また, 触媒上への炭素質と金属成分のたい積量が多くかつ炭素質のコーク化が進行していることが明らかになった。また, 反応水素圧が高い場合には, 触媒上にたい積した炭素質のコーク化が抑制され, かつ触媒上の金属成分のたい積量が抑えられることが分かった。

Y-zeolite supported catalysts were applied to the hydrocracking of coal-derived liquids. By the introduction of two-stage upgrading consisting of hydrotreating and hydrocracking, Wandoan coal-derived middle distillate was hydrocracked over NiMo/Y-zeolite, producing a high gasoline fraction yield. Zeolite supported catalysts gave little hydrocracked compounds in the hydroprocessing of coal-derived heavy oils, even after hydrotreatment. The reaction inhibitors which seriously poison the active sites of zeolites were found to be small nitrogen-containing molecules. In the hydroprocessing of coal-derived heavy oils, zeolite supported catalysts were inferior to alumina supported catalysts. This is due to the high hydrocracking but low hydrogenation activity of zeolite supported catalysts.

Hydrothermal synthesis of ferrisilicate of ZSM-5 structurewas followed by FT-IR, XRD, XPS, XRF, TG, and EXAFS. It was found that the micro-structure around Fe formed before instantaneous crystallization of the bulk.

Fischer–Tropsch (F–T) synthesis was carried out on the Fe powder catalyst prepared by the reduction of FeI2 with potassium metal in refluxing tetrahydrofuran (THF). 1-Butene was obtained with 37 wt% selectivity and a rather high conversion of 12 wt% by an autoclave system at 553 K. After H2-pretreatment of the Fe powder at 573 K, propylene was produced as the major product (15 wt% selectivity) under otherwise the same experimental conditions. In a conventional flow system with a stream of H2, H2/CO, and CO during a heatup period of the reactor to 533 K, C3, C4, and C5 olefins were produced as major products, respectively. The synthesized Fe powder contains 1.6 wt% of carbon, which may be produced by the decomposition of THF in preparation of the catalyst. During the gas-pretreatment of the Fe powder in the flow reactor, evolution of CH4 CO2, and CO was observed. The amount of carbon on the Fe powder produced after the gas-pretreatment varied with the pretreatment gas in the order, CO > H2/CO > H2. Quantit...

XANES and EXAFS analysis of Cu ion-exchanged ZSM-5 zeolite, a highly active catalyst for NO decomposition, is performed. The copper species in the zeolite are Cu(II) ions in the zeolite cages. The contribution of Cu-Cu local structure is suggested for high loading samples. The Cu atoms in the zeolite are more ionic than CuO. The analysis of the catalyst deactivated by SOx treatment suggests the presence of Cu atoms surrounded by SO4 ions which blocks the adsorption of NO molecules.

重質炭化水素資源の水素化精製 (脱硫, 水素化分解等) に用いられているMo系硫化物担持触媒の表面構造に関する研究を2テーマに分けて解説した。前半では, 脱硫反応に高活性を示す “Co-Mo” 触媒におけるCo硫化物とMo硫化物の相乗作用に関する研究に焦点を絞り, これまでに提唱された “Co-Mo” 硫化物の構造モデルを紹介した。近年では, Co8S9とMOS2との接触により高活性が発現すると仮定する “contact synergy model” とMoS2のedge部にCoが配置して高活性サイトを形成する “Co-Mo-S” 相の両モデルの間で議論が行われている。両モデルともに, 各種キャラクタリゼーションの他, 反応速度等の詳細な解析に基づいて提唱されたもので, 分子・原子レベルでの触媒構造の議論として極めて興味深い。後半では, 触媒設計を目指した触媒構造と触媒機能の相関についての研究を紹介した。Mo系硫化物触媒の機能は担体により大きく変化することから, 各種担体に担持された触媒の機能, 構造を明らかにし, ついで触媒の構造と触媒機能との相関について討論を行った。さらに, Moの担持量によりMoS2の集合状態が変化することから, 集合状態と触媒機能の相関についても検討が行われた。これらの結果に基づいて, MoS2の活性点についてもモデルが提出されている。以上, 従来経験に基づいて調製されていたMo硫化物触媒が, 最近, より高性能の触媒開発を目的として学問的にも解明されつつあり, 学問体系に基づいた “触媒探索”, “触媒設計” へと進みつつある。

Pentasil-Structured bimetallosilicates were prepared by adding Ga and Fe (or Sr) salts simultaneously during the hydrothermal synthesis of a pentasil silicate, and local structures around Ga were directly elucidated by means of EXAFS for the first time. It was found that Fe and Ga independently substituted the silicate framework, and that the local structure around Sr was the same as that in Sr2+-exchanged gallosilicate.

Crystallite size determination of MoS2particles is still a controversial problem fuelling the debate on the morphology of hydrotreating catalysts. The size of MoS2crystallites determined from extended X-ray absorption fine structures (EXAFS) is close to 1 nm, whereas TEM picture analysis give an average size of 3 to 4 nm. It is obvious that these techniques have intrinsic strengths and weaknesses and that the results may not be comparable because of these differences. However, it is our intention to obtain a better understanding of these crystallite sizes by studying the dispersed unsupported solids. Various techniques were used: nitrogen adsorption–desorption, X-ray diffraction (XRD), XAFS, TEM, and temperature-programmed reduction (TPR) and the results were compared and discussed. The samples were prepared by thiosalt decomposition or molten salt synthesis. These solids presented different morphologies, the latter method providing higher surface area samples. The specific surface areas varied from 4 to 125 m2/g and, depending on the method of preparation, microporous and mesoporous solids were obtained. XRD, TEM, and TPR were found to be complementary and coherent methods for determining the size parameter. EXAFS interpretation does not give consistent results due to local reorganization at the periphery of the crystallites.

Ni-Mo sulfide catalysts supported on the mixtures of γ-Al 2 O 3 and HY zeolite with various ratios were prepared and tested in the hydroprocessing reactions of heavy oils to reveal the roles of the dual-functions of hydroprocessing catalysts. Hydrogenation activity solely functioned for the hydrodesulfurization and hydrodearomatization of heavy feedstocks with high nitrogen contents, typically oil sand bitumen and coal-derived oils. For other feedstocks, the dual-functionality played important roles not only in hydrocracking but also in hydrodenitrogenation. The optimum balance of the hydrogenation/hydrocracking activities greatly depend on the feedstock properties. Pre-hydrotreatment which reduced the concentration of heavy nitrogen-containing materials was effective for maximizing the dual-functionality.

Publisher Summary This chapter focuses on the analysis of X-ray absorption fine structure (XAFS) in which multiple scattering effect considered to obtain more precise information on the local structure around Ni and W in the catalyst. A highly active Ni-W/Al 2 O 3 catalyst is developed to upgrade coal-derived liquids that are characterized using XAFS method. Local structures around Ni and W in the fresh catalyst are basically the same as those around Ni and Mo, respectively, in Ni-Mo catalysts. The changes in the local structures around W and Ni on the catalysts showed that most of W occurs as WS 2 crystal and Ni as Ni 3 S 2 crystal. These results suggest that the catalytically active phase of Ni-W-S structure decompose into bulk single sulfides after use in the upgrading reaction of coal-derived liquids.

Publisher Summary This chapter discusses the use of zeolite catalyst in the hydrocracking of coal volatile matter to yield benzene, toluene, xylenes (BTX). Coal can be economically utilized in the production of high value-added chemicals, such as BTX and phenol, cresols, xylenols (PCX), followed by using the residue as the energy sources. Continuous catalytic reaction is carried out by pyrolyzing coal at 800°C in a free-fall reactor and evolved volatile matter hydrotreated at 600°C by using ultrastable Y-zeolite, which is active in the production of BTX from coal volatile matter. The deactivation of catalyst is not observed under the present conditions even in the continuous operation. The use of model compounds showed the high activity of zeolite catalyst in the hydrogenation and hydrocracking reactions.

Organometallic complexes of Ni or Co were doped on a MoO 3 /Al 2 O 3 catalyst to enhance the hydrogenation (HY) activity of molybdenum sulfide catalysts and to help understand the nature of the HY active sites. The HY activity increased with increasing doping with the organometallics. The HY activity of nickel phthalocyanine Ni(Pc)-MoO 3 /Al 2 O 3 catalysts were much higher than those of conventionally prepared NiO-MoO 3 /Al 2 O 3 catalysts. XAFS, FT-IR, and thermal analysis revealed that the Ni(Pc) structure on the catalysts was fairly stable during calcination and presulfiding. These results indicated that the Ni(Pc) structure on the catalysts is effective for the formation of the HY active sites. Since there is no direct bond between Mo in MoS 2 and Ni in Ni(Pc), hydrogen spillover seems to play an important role in enhancing the HY activity of the catalysts.

A highly active Ni-W/Al 2 O 3 catalyst was developed to upgrade coal-derived liquids. Compared to conventional Ni-Mo catalysts, the Ni-W catalyst was found to have higher hydrogenation and lower hydrocracking activities. Because of these properties, the Ni-W catalyst showed high hydrodenitrogenation activity and slow deactivation for feedstocks with a large amount of catalyst poisons.

Publisher Summary This chapter explores the ruthenium promoted nickel-molybdate catalysts for hydrotreating coal-derived oils. Coal-derived oils are highly aromatic and contain high amounts of heteroatoms such as nitrogen and oxygen. To upgrade these oils to the levels of petroleum products, aromatics must be hydrogenated and hydrocracked in addition to the removal of those heteroatoms. In a study described in the chapter, the NPD gas chromatogram data showed that heavier refractory nitrogen-containing compounds were effectively removed with increasing the SGO mixing ratio for the RuNiMo catalysts. A gradual and significant synergistic effect was observed for the CoMo and RuCoMo catalysts, but hydrodenitrogenation (HDN) activity was slightly higher activity for the RuCoMo catalyst. This significant synergistic effect might be attributable to the effective dilution of oxygen containing compounds in the feedstock. Quite a similar synergistic effect was observed in co-refining coal-derived oil and sulfur-free n -C 16 paraffin that contained no sulfur over the RuNiMo catalyst. This indicated that the main role of the diluting agents was to lower the competitive adsorption of oxygen-containing compounds to the HDN active sites, and resulting transformation of active sulfidic states of active metals to less active oxidic and sulfate states.

Publisher Summary This chapter explores the characteristics and catalytic behavior of new Ni–W catalysts developed for upgrading coal-derived liquids. A new generation of highly active catalyst that enables to reduce aromatics and hetrocompounds is required for practical utilization of coal-derived liquids. Production of gasoline from middle and heavy distillates seems to be the most suitable utilization of coal derived liquids because of their unconventional properties for kerosene or light oil. Hydrocracking reaction on zeolite catalyst was found to proceed after hydrogenation of aromatic rings. Acid sites of zeolite catalysts were easily poisoned by nitrogen containing compounds. Hydrodenitrogenation and hydrogenation of the aromatic rings are necessary before catalytic hydrocracking. The chapter presents an investigation of catalysts for a two-stage upgrading process consisting of hydrogenation and hydrocracking of coal-derived liquids. Based on the understanding of fundamental research, two types of Ni–W catalysts each possessing high hydrogenation and hydrocracking activity were designed and prepared for the first- and second-stage upgrading, respectively. The two kinds of catalysts were then applied to the two-stage upgrading. The two types of the catalysts used in the two stage process showed a great improvement in overall activity and initial deactivation as compared to commercially available catalysts.

The C K-edge XANES spectra of carbon nanotubes and two fullerenes are presented. The XANES of the nanotubes is quite different from those of fullerenes, but analogous to that of HOPG. The difference in the 1 s → π ∗ transition is discussed in conjunction with the structural features.

The crystallization of ZSM-5 type ferrisilicate during hydrothermal synthesis has been studied by means of Si and Fe K edge XAFS. The results indicate that the precursor of the ZSM-5 framework containing Fe is formed at an early stage of the synthesis, followed by instantaneous crystallization in a short period.

C K-edge X-ray absorption near-edge structure of the carbon nanotubes was measured by monitoring the total electron yield from the sample. The spectrum shows similar features to those of graphite except the feature between the lowest anti-bonding π and σ bands called the interlayer band.

X-ray absorption spectra of several silicon compounds with high S/N ratios were obtained over a wide energy span, up to 950 eV above the silicon K-edge monitoring total electron yields from the sample. EXAFS analysis of a CVD thin film of Si3N4 elucidated the presence of contaminated Si metal in the α-Si3N4 structure. EXAFS and XANES analyses detected SiC crystallites in a CVD thin film of SiC, which could not detected by X-ray diffraction.

The structures of fresh and aged Ni–W catalysts supported on Al2O3 have been analyzed by the XAFS techniques. The local structures around Ni and W in the fresh catalyst were found to be basically the same as those around Ni and Mo, respectively, in Ni–Mo catalysts. For aged catalysts, apparent increases in the coordination numbers of S and W around W were observed relative to the fresh catalyst. The local structure around Ni dramatically changed after aging for 950 h. These results suggest that WS2 slabs grow in the lateral direction during the reaction and that Ni atoms are released from the edge sites of the WS2 slabs.

A new analytical method of EXAFS is proposed by modifying the Maximum Entropy Method (MEM). The appropriate term number (m) of the prediction error filter is derived according to a specific criterion in this work. This newly developed MEM showed a great improvement in both resolution and reliability of the spectra for EXAFS.

The structure around cobalt in a series of Co-Mo/Al2O3 catalysts was studied by means of the X-ray Absorption Fine Structure technique. Low Co loading yields the dominant phase of a Co-O-Mo (I) structure, in which six-coordinated Co atoms on the Al2O3 surface have appreciable interaction with Mo atoms. An increase of the Co loading leads to pronounced formation of a CoAl2O4-like structure which is mainly present at the subsurface of Al2O3. CoMoO4 microcrystallites (Co-O-Mo (II)) are found to be formed independent of the Co/Mo ratio in the catalysts with high Mo loadings. Both Co-O-Mo (I) and Co-O-Mo (II) are postulated as precursors which transfer to the active “Co-Mo-S” phase during sulfiding of the catalysts.

Coal liquefaction experiments were carried out by using seven catalysts with different pore structures. As for the unimodal catalysts, the total conversion increased with the pore radius of the catalyst because of the lesser pore-diffusional limitation. However, the ratio of oil to oil-plus-asphaltene decreased with the pore radius. In the case of a large-pore catalyst, heavy components with a large molecular size and a low reactivity can approach the intra-particle active sites and occupy them to prevent the hydrocracking of asphaltene to oil. Bimodal catalysts with micropores (r 300 nm) gave higher values of both the coal liquefaction and the oil yields than did the unimodal catalysts. The presence of macropores seems to enhance the pore diffusion and increase the efficiency of the micropore use, while mesopores with radii between 10 nm and 300 nm did not make such a high contribution to the pore diffusion as was shown for the macropores. For the removal of heteroatoms, there wa...

In order to make clear the behavior of coal mineral remaining in coal liquid on the hydrotreating catalyst, a Wandoan coal derived liquid containing high contents of liquefaction solid was hydroprocessed over the Ni-Mo-γ-Al2O3 catalyst having bimodal pore size distributions.In these liquefaction residues, kaolin and quartz were not chemically altered and magnetite was undergone chemical transformation to pyrrhotite during hydroprocessing. From the shell like deposits of these metals around the spent cata lysts, these matters might be finely dispersed particles that had equivalent spherical diameter larger than about 1-2μm, which corresponded to maximum size of macropore in used catalysts.Titanium and calcium metals, which were more concentrated in THF insoluble residue in feed coal liquid, were tend to accumulate in preasphaltene after hydro processing. Furthermore from the more penetrated depth profile of titanium and calcium metals, these metal containing matters might have equivalent spherical diam eter larger than about 0.6μm and 4.4nm micro-pore diameter were too small to be utilized against carbonaceous material deposits. Because active sites might be occupied with sodium metal, which interacted more strongly with those than titanium and calcium metals, titanium and calcium metals migrated more deeper on the catalyst pore walls by surface diffusions.As a result, silicon and iron metals were tend to plug the catalyst pore mouth and sodium, alkaline earth metals and titanium metals were tend to poison active sites and change micro-pore structure.

Hydrocracking reactions of diphenylmethane under high H2 pressure were carried out to elucidate the requisite properties of the support for molybdenum catalysts. The effectiveness order of the supports was TiO2 > SiO2 > ZrO2 > γ-Al2O3 > MgO.

The behavior of carbonaceous and metallic depositions on catalysts during hydroliquefaction of coal was investigated by using several kinds of catalyst supports with different pore-size distribution values in order to obtain the fundamental data for designing long-life catalysts. Higher concentration of carbonaceous deposition was observed on large-pore and bimodal catalysts than was observed on the comparative small pore and unimodal catalysts, respectively. However, the carbonaceous deposit was distributed more evenly inside large pores than it was inside small pores. The micropores of the bimodal catalysts were more effectively used than were those of the unimodal catalysts. Thus, the unimodal catalysts with small pores suffered more severe pore-mouth poisoning than the bimodal or the large-pore catalysts. The penetration behavior of the metallic components was found to be different for each metal. Discrete minerals such as clay could not penetrate into the catalyst pores and were deposited on the exte...

液化油の水素化処理中に起こる触媒上への炭素質析出防止対策としてアルカリ土類修飾による触媒の酸性質制御を試みた。修飾触媒では炭素質たい積抑制の効果は認められたが液化油の水素化脱窒素活性は低下した。修飾効果は原料油によって異なり, アスファルテンを含む重質油の場合, Mg修飾が炭素質たい積の抑制に有効でありかつ活性低下が少なかった。Ca修飾は酸性質制御の効果は大きいが触媒基本活性の低下も大きいため, 炭素質たい積の抑制には有効である一方, 液化油脱窒素活性の低下は大きかった。Ca修飾触媒では, たい積炭素質のコーク化が進行しており, コーク析出の抑制には酸性質制御と同時に水素化活性を賦与することも重要であると推察された。

The deactivation behavior of molybdenum catalysts used for hydrotreating coal-derived liquids is reviewed to obtain information for the design concept for long-life catalysts. Causes for the catalyst deactivation are fundamentally similar to those for catalysts us-ed in petroleum hydroprocessing. However, the deactivation patterns for the catalysts in coal-derived liquid hydroprocessing was different from that found in petroleum hydroprocessing. This is mainly due to differences between coal liquid and petroleum feeds. Characterization of spent catalysts revealed certain differences in features of metal and carbonaceous deposits resulting from the use of coal liquids and petroleum. The changes in physical and chemical pro-perties of used hydroprocessing catalysts are discussed for coal liquids and petroleum, respec-tively. Changes in the local structure of active metals were found to decrease catalyst activity during coal liquid hydrotreating. Based on understanding of the catalyst deactivation, remedies for catalyst deactivation in connection with the development new types longife catalysts are also discussed.

Perovskite, a SYNROC host mineral for nuclear wastes, is thermodynamically unstable in natural waters and in association with common minerals. Leach experiments demonstrate that CaTiO3 (perovskite), SrTiO3 and BaTiO3 are as reactive as some silicate glasses below 100°C, but leach much more slowly than glasses above 100°C.

Counter anions of active components on catalysts were found to affect catalytic activities for NO reduction with NH3. Halide ions promoted activity in copper and iron catalysts, but lowered it in chromium and manganese catalysts. The most favorable electronic state of a cation on catalysts was investigated by changing counter anions and/or carriers.

The Australian brown coal-derived oil mixed with a hydrogenated creosote oil was hydrotreated over NiMo and CoMoγAl2O3 catalysts. The initial catalytic activities varied with the reaction for each catalyst: converting of the hexane-insolubles to the hexane-soluble oils(HDHI) > hydrodesulfurization(HDS) > hydrodenitrogenation(HDN) > hydroconverting of the 623 K+ residues to the 623 K− oils(HDC). A NiMo catalyst showed higher activities than a CoMo catalyst did. The initial catalyst deactivation was significant in the order of HDC > HDN > HDS > HDHI for each catalyst. The degrees of the deactivation were larger for a CoMo catalyst. The analyses of the spent catalysts showed that the pore volumes and the surface areas were decreased markedly by the carbonaceous deposits, in which higher amounts of the N- and O-containing compounds accumulated. The XPS and elemental analyses of the spent catalysts indicated that the decreases in the amounts of sulfur during the course of run were linked with the decreases in the sulfidic states of molybdenum(Mo4+ species) and the promoters. These carbonaceous deposits and the changes in chemical states of the supported metals were interpreted as the main reasons for the initial catalyst deactivation.

The characterization of Nio–MoO3–Al2O3 catalyst used for coal liquefaction was performed using some spectrometers. Behaviors of metal elements deposited on the catalyst, such as Fe, Ti, Ca, and Na, were clarified in this work.

The effect of counter anions on the catalytic activities of cupric and ferric ions, when salts of them are used as catalysts for the reduction of nitric oxide with ammonia, was investigated. The order of the co-catalyst activity of the counter anions investigated is Br−, Cl−, SO42−, and O2−.