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Chinese Journal of Catalysis
2012, Vol. 33, No. 1
Online: 16 January 2012


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A copper-amine complex, which had the proper conformation and appropriate size to fit well in CHA cages as a template, for the one-pot synthesis of high silica Cu-CHA zeolites was designed by Prof. Feng-Shou Xiao’s group. The zeolites produced with a high copper content and good dispersion of the copper species gave a superior catalytic performance in the NH3-SCR reaction. See the article on pages 92–105.

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Table of Contents for Vol. 33 No. 1 2012, 33 (1):  0-0.  Abstract ( 1244 )   PDF (1222KB) ( 1198 )

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Preface Special Issue on Catalysis by Zeolites 2012, 33 (1):  1-2.  Abstract ( 1207 )   [Full Text(HTML)] () PDF (76KB) ( 676 )

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Industrial Outlook on Zeolites and Metal Organic Frameworks Bilge YILMAZ, Natalia TRUKHAN, Ulrich MULLER 2012, 33 (1):  3-10.  DOI: 10.1016/S1872-2067(10)60302-6 Abstract ( 3484 )   [Full Text(HTML)] () PDF (208KB) ( 3884 )   Crystalline nanoporous materials serve numerous pivotal functions in industrial chemistry. They provide crucial features for industrial applications, such as high surface area, uniform porosity, inter-connected pore/channel system, accessible pore volume, high adsorption capacity, ion-exchange ability, enhanced catalytic activity, and shape/size selectivity. As a well-established family of nanoporous materials, zeolites are of vital importance for the chemical and petrochemical industries. An emerging class of porous materials called metal organic frameworks (MOFs) also offer promise in various applications. Both zeolites and MOFs can play significant roles in fields that are critical for the future of our industrialized society. In the quest for raw material change, zeolites serve as catalysts providing the required shape/size selectivity towards base chemicals. In global efforts to transition into other transportation fuels such as Hydrogen, MOFs serve as the energy storage media. In the fight against environmental pollution, zeolites not only take part in capture and abatement of harmful substances, but also offer environmentally benign alternatives for many industrial processes. In this review, an industrial perspective on the synthesis and utilization of zeolites and MOFs for current and future applications is presented.

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Methyl Halide to Olefins and Gasoline over Zeolites and SAPO Catalysts: A New Route of MTO and MTG WEI Yingxu, ZHANG Dazhi, LIU Zhongmin, SU Bao-Lian 2012, 33 (1):  11-21.  DOI: 10.1016/S1872-2067(10)60303-8 Abstract ( 3056 )   [Full Text(HTML)] () PDF (531KB) ( 1188 )   Rational and efficient conversion of methane to more useful higher hydrocarbons is one of the most important topics of natural gas utilization. Although methane activation and its conversion to valuable compounds attract an increasing attention, methane conversion is often made in indirect way through the very energy-consuming step for syngas production from steam reforming of methane. Some promising results appeared to be of significance for the development of an alternative and potential route for the production of high value-added products from methane. Efficient conversion of methane to higher hydrocarbons could be realized via methyl halide as the intermediate. After the production of halomethane, they could be transformed to gasoline and light olefins over modified zeolites and SAPO molecular sieves. High conversion efficiency and selectivity indicated the feasibility of industrial application. The research gained recently growing interest from the point of view in both fundamental research and industrial application. The study on the reaction mechanism shed light on the possible route of C–C bond construction from methyl halide, which is the very important issue of the C1-reactant conversion to higher hydrocarbons. Hydrogen halide generation during methyl halide conversion did not exert apparent impact on the reaction mechanism and the structure stability of the catalysts. This review deals with the evolution of the field and comments the advantages to be explored and the drawbacks to be prevented for the development of new and sustainable methane-to-olefins (MTO) and Methane-to-gasoline (MTG) routes via methyl halides.

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Thoughts on the Future Development of Zeolitic Catalysts from an Industrial Point of View LIU Zhi-Cheng, WANG Yang-Dong, XIE Zai-Ku 2012, 33 (1):  22-38.  DOI: 10.1016/S1872-2067(10)60299-9 Abstract ( 3816 )   [Full Text(HTML)] () PDF (624KB) ( 3033 )   Problems and challenges in the production and catalysis of zeolitic catalysts were addressed from an industrial point of view. The recent progress and developments in zeolitic catalysts were reviewed. The highly efficient catalysis of zeolitic catalysts, the synthesis and application of novel zeolitic catalysts, the economic production of zeolites, the application of zeolites to environmental protection and green chemistry, etc., were covered. It is intended to stimulate thought and focus on the future development of zeolitic catalysts with regard to economic synthesis, catalyst design, high efficiency catalysis, green processes, new applications, etc.

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Research Progress into Ionothermal Synthesis of Molecular Sieves WANG Ya-Song, XU Yun-Peng, TIAN Zhi-Jian, LIN Li-Wu 2012, 33 (1):  39-50.  DOI: 10.1016/S1872-2067(1)60343-4 Abstract ( 2802 )   [Full Text(HTML)] () PDF (506KB) ( 1403 )   Ionothermal synthesis is a new method for the synthesis of molecular sieves and it takes advantage of an ionic liquid or a deep eutectic mixture as a medium. Ionothermal synthesis offers an ionic environment and an opportunity to obtain novel molecular sieves and determine the mechanism of molecular sieve synthesis. A brief review about the progress in the ionothermal synthesis of molecular sieves is summarized and includes innovations in the synthesis method, determination of the synthesis mechanism and the preparation of novel molecular sieves and new catalysts. Future development in the ionothermal synthesis of molecular sieves is also discussed.

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Recent Development of Nitrogen-Incorporated Molecular Sieves WU Guang-Jun, GUAN Nai-Jia, LI Lan-Dong 2012, 33 (1):  51-59.  DOI: 10.3724/SP.J.1088.2011.10764 Abstract ( 3128 )   [Full Text(HTML)] () PDF (511KB) ( 1329 )   Nitrogen-incorporated molecular sieves, a new family of hybrid molecular sieves, have drawn extensive attention, because of their basic catalytic properties with shape selectivity and acid-basic bifunctional catalytic properties. In this paper, recent research and developments on the preparation, characterization, and catalytic application of nitrogen-incorporated molecular sieves are reviewed. Special emphasis is laid on the nitridation mechanism and theoretic calculations on nitrogen-incorporated molecular sieves. Finally, research and developments in the near future on nitrogen-incorporated molecular sieves are prospected.

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Progress on the Adsorption and Degradation of Nitrosamines by Zeolites WAN Mi-Mi, ZHU Jian-Hua 2012, 33 (1):  60-69.  DOI: 10.3724/SP.J.1088.2011.10657 Abstract ( 2826 )   [Full Text(HTML)] () PDF (562KB) ( 1351 )   Nitrosamines are well-recognized carcinogens, and nitrosamines in smoke causes health hazard by smoking. How to adsorb and catalytically degrade nitrosamines in the environmental tobacco smoke with complex composition becomes the challenge facing zeolite material. In this article some latest research progresses in adsorption and catalytic degradation of nitrosamines by zeolites are reviewed. The special selectivity of zeolite toward nitrosamines and the degradation of nitrosamines by zeolite are described, and how to elevate the efficiency of zeolite with metal compounds modification is introduced. Also, the research progress on the removal of nitrosamines is summarized. Finally the development of new functional materials to eliminate the pollution of nitrosamines is prospected.

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Catalytic Ring Opening of Perhydroindan - Hydrogenolytic and Cationic Reaction Paths Giuseppe BELLUSSI, Andreas HAAS, Sandra RABL, Dominic SANTI, Marco FERRARI, Vincenzo CALEMMA, Jens WEITKAMP 2012, 33 (1):  70-84.  DOI: 10.1016/S1872-2067(10)60278-1 Abstract ( 2634 )   [Full Text(HTML)] () PDF (272KB) ( 1044 )   Perhydroindan (bicyclo[4.3.0]nonane) was converted in a flow-type apparatus under a hydrogen pressure of 5 MPa on six different catalysts, namely on a bifunctional Pd/Na,H-Beta zeolite, on Ir/Na,H-Y and Pt/Na,H-Y zeolites with a low concentration of Brønsted acid sites, and on three catalysts containing the three noble metals on the non-acidic support silica. On the bifunctional zeolite Pd/Na,H-Beta, skeletal isomerization of perhydroindan was the primary reaction followed by opening of one naphthenic ring, the formation of open-chain nonanes in low yields of ca. 6%, and hydrocracked products C8-. The carbon number distribution of the latter was volcano-shaped with no C1, C2, C7, and C8 indicating a carbocationic hydrocracking of C9 precursors with one naphthenic ring. On Ir/Na,H-Y and Pt/Na,H-Y (“high-performance ring-opening catalysts”), ring opening and hydrocracking to C8- occurred by hydrogenolysis on the respective metal. Opening of the five-membered ring was found to be much faster than opening of the six-membered ring, in agreement with literature reports. The maximal selectivities of open-chain nonanes (OCNs) attained on Ir/Na,H-Y and Pt/Na,H-Y were very high, viz. 49% and 54%, respectively, and significantly better than those of the open-chain decanes observed previously with decalin as model hydrocarbon. The OCNs formed on Pt/Na,H-Y were much less branched than those formed on Ir/Na,H-Y which was interpreted in terms of the different hydrogenolysis mechanisms on both metals. Valuable ancillary mechanistic information was obtained from the selectivities of perhydroindan hydroconversion on the three noble metals on silica. In contrast to Pd/silica, Ir/silica and Pt/silica gave appreciable selectivities of OCNs as well, yet the maximum values of these selectivities were lower than those obtained on the two high-performance zeolite catalysts.

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A Dynamic Organic Structuring-Directing Agent for Pure-Silica-Zeolite AST and LTA Syntheses Minwei SUN, Heather K. HUNT, Christopher M. LEW, Rui CAI, Yan LIU, Yushan YAN 2012, 33 (1):  85-91.  DOI: 10.1016/S1872-2067(10)60291-4 Abstract ( 2516 )   [Full Text(HTML)] () PDF (555KB) ( 941 )   Pure-silica-zeolite (PSZ) AST and LTA are synthesized successfully by using the same structure-directing agent (SDA) molecule, but at different concentrations. A dynamic organic SDA is proposed to discuss the mechanism of phase discrimination between AST and LTA. Data suggest that the SDA molecules can self-assemble into dimer or trimer complexes at different concentrations by π-π interactions, and these differences can be taken advantage of to selectively synthesize either PSZ AST or LTA. These deviations from the Liebau’s rules indicate that small changes in SDA chemistry, structure, and order in solution can have a great impact on the structure selectivity of the zeolite synthesis.

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Design and Synthesis of a Catalytically Active Cu-SSZ-13 Zeolite from a Copper-Amine Complex Template REN Li-Min, ZHANG Yi-Bo, ZENG Shang-Jing, ZHU Long-Feng, SUN Qi, ZHANG Hai-Yan, YANG Cheng-Guang, MENG Xiang-Ju, YANG Xiang-Guang, XIAO Feng-Shou 2012, 33 (1):  92-105.  DOI: 10.1016/S1872-2067(10)60280-X Abstract ( 3647 )   [Full Text(HTML)] () PDF (1004KB) ( 1661 )   The modern synthesis of zeolites typically uses organic structure-directing agents. Therefore, the developing of new templates is part of zeolite research. The design and synthesis of Cu-SSZ-13 using a novel template of a low-cost copper amine complex (Cu2+ coordinated with tetraethylenepentamine) were reported, where the copper amine complex is both a template for synthesizing the SSZ-13 structure and a source of copper species in the zeolite. The calculated size of the complex (0.728 nm ´ 0.922 nm) matches well with the CHA cages (0.73 nm ´ 1.2 nm), which are the building units of the SSZ-13 zeolite. Various techniques were used to investigate the chemical and physical properties of the synthesized zeolite. The results showed that the sample has the SSZ-13 zeolite structure, high crystallinity, adjustable Si/Al ratios, and controllable copper loading. Catalytic tests using the selective catalytic reduction of NOx with NH3 showed that the Cu-SSZ-13 was a superior catalyst, and it can be important for the abatement of environmentally harmful NOx.

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UV Raman Spectroscopic Studies on the Mechanism of FeAlPO4-5 Synthesis GUO Qiang, FAN Feng-Tao, GUO Mei-Ling, FENG Zhao-Chi, LI Can 2012, 33 (1):  106-113.  DOI: 10.1016/S1872-2067(10)60281-1 Abstract ( 2833 )   [Full Text(HTML)] () PDF (568KB) ( 953 )   FeAlPO4-5 samples with various iron contents were investigated by UV resonance Raman spectroscopy and UV-Vis spectroscopy. The Raman spectra of FeAlPO4-5 show four feature bands related to the framework iron at 630, 1060, 1140, and 1210 cm-1 when excited by 266 nm laser. It is found that only part of ferric ions could enter into the framework, while the others exist in the extra-framework in the form of six-coordinated state. This kind of iron gives characteristic Raman band at 285 cm-1. Combined with UV resonance Raman spectroscopy, UV-Vis spectroscopy, and X-ray diffraction, the crystallization process of FeAlPO4-5 (Al/Fe = 760) was studied. It is found that, in the early stages of the crystallization, the iron species exist in the form of six-coordinated state while attached to the end of the 1-dimensional AlPO4 chain. The Fe-O bonds in the six-coordinated state hamper the crystallization of AlPO4. The crystallization of the FeAlPO4-5 began when the reaction between the 1-dimensional AlPO4 chains occurred. At the same time, the six-coordinated ferric ions converted to the tetrahedral iron.

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Preparation of a Carbon-Silica Mesoporous Composite Functionalized with Sulfonic Acid Groups and Its Application to the Production of Biodiesel FANG Lin, ZHANG Kun, LI Xiao-Hong, WU Hai-Hong, WU Peng 2012, 33 (1):  114-122.  DOI: 10.1016/S1872-2067(10)60282-3 Abstract ( 3051 )   [Full Text(HTML)] () PDF (617KB) ( 973 )   A carbon-mesoporous silica (CS) composite functionalized with sulfonic acid (–SO3H) groups was prepared by controlled carbonization of sucrose impregnated in SBA-15 mesoporous silica and its subsequent sulfonation. The moderate vapor phase sulfonation of the CS composite with fuming sulfuric acid (H2SO4?20%SO3) was the key step in preparing the strong acid solid material (CS-SO3H). Structural analysis and reaction data revealed that sulfonic acid groups were successfully incorporated into the mesoporous CS composite, and the Brønsted acid site density was tunable from 0.09 to 0.70 mmol/g by tuning the carbon loading. The sample with 35 wt% carbon exhibited a remarkable catalytic activity for biodiesel production by the esterification of palmitic acid and the transesterification of soybean oil with methanol.

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Preparation and Photocatalytic Activity of Lanthanide Loaded Microporous Titanosilicate ETS-10 Catalysts REN Yuan-Hang, GU Min, HU Yi-Chen, YUE Bin, JIANG Lei, KONG Zu-Ping, HE He-Yong-b 2012, 33 (1):  123-128.  DOI: 10.1016/S1872-2067(10)60293-8 Abstract ( 2943 )   [Full Text(HTML)] () PDF (477KB) ( 1043 )   The three dimensional microporous titanosilicate, ETS-10, was synthesized by a hydrothermal synthesis route using TiCl4 and a sodium silicate aqueous solution as starting materials. Lanthanide (La, Ce, Pr, Nd) loaded ETS-10 catalysts were prepared by the impregnation method. The catalysts were characterized by X-ray diffraction, 29Si magic angle spinning NMR, UV-Vis diffuse reflectance spectroscopy, N2 adsorption-desorption measurement, and X-Ray fluorescence spectroscopy. The degradation of methyl orange under near-UV light was used to investigate the photocatalytic activity of the catalysts in aqueous suspensions. The lanthanide loaded ETS-10 catalysts exhibit higher activity than the unmodified ETS-10. The combination of loading lanthanide and increasing the surface defects of ETS-10 by a HF treatment gave an enhancement of the photocatalytic activity, which became comparable with that of anatase TiO2.

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Brønsted/Lewis Acid Sites Synergy in H-MCM-22 Zeolite Studied by 1H and 27Al DQ-MAS NMR Spectroscopy YU Zhi-Wu, WANG Qiang, CHEN Lei, DENG Feng 2012, 33 (1):  129-139.  DOI: 10.1016/S1872-2067(10)60287-2 Abstract ( 3703 )   [Full Text(HTML)] () PDF (716KB) ( 1485 )   Brønsted/Lewis acid sites synergy in H-MCM-22 zeolite was studied by solid-state nuclear magnetic resonance (NMR). Two-dimensional 1H double quantum-magic angle spinning (DQ-MAS) NMR revealed the details of the spatial relationship between the Lewis and the Brønsted acid sites in a dealuminated H-MCM-22 zeolite, which implied the existence of a Brønsted/Lewis acid sites synergy. Two-dimensional 27Al DQ-MAS NMR was used to give the details of the spatial proximities of various aluminum species. The Brønsted/Lewis acid sites synergy occurred in the supercage of the H-MCM-22 zeolite between a T6 site Al and extra-framework Al species. 13C CP/MAS NMR of adsorbed acetone demonstrated that the spatial proximities of the Brønsted and Lewis acid sites led to a synergy that enhanced the Brønsted acid strength of the dealuminated zeolites. 1H MAS NMR of adsorbed deuterated pyridine confirmed that the Brønsted/Lewis acid sites synergy occurred in the supercage of H-MCM-22. This finding is important for understanding the mechanism of acid-catalyzed reactions on H-MCM-22 zeolites.

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Improving the Hydrothermal Stability of Mesoporous Silica SBA-15 by Pre-treatment with (NH4)2SiF6 SONG Ming-Juan, ZOU Cheng-Long, NIU Guo-Xing, ZHAO Dong-Yuan 2012, 33 (1):  140-151.  DOI: 10.1016/S1872-2067(10)60283-5 Abstract ( 2899 )   [Full Text(HTML)] () PDF (1975KB) ( 1268 )   The hydrothermal stability of the mesoporous silica material SBA-15 was improved by a pre-treatment of 5 mol% ammonium hexafluorosilicate solution with 1 mol% SiO2 ratio of (NH4)2SiF6 and SBA-15. The modified SBA-15 kept its ordered meso-structure well even when kept under boiling water for 14 d or 100 % H2O stream at 800 °C for 12 h, and still had BET surface areas as high as 310 and 213 m2/g, respectively, after these treatments. The possible reasons for the stabilization were that the surface defects of SBA-15 were partially repaired by silicon insertion and some silicon hydroxyls were replaced by F- ions. Larger amounts of ammonium hexafluorosilicate did not give more stabilization.

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Desilication by Alkaline Treatment and Increasing the Silica to Alumina Ratio of Zeolite Y SHEN Bao-Jian, QIN Zheng-Xing, GAO Xiong-Hou, LIN Feng, ZHOU Shu-Ge, SHEN Wen, WANG Bao-Jie, ZHAO Hong-Juan, LIU Hong-Hai 2012, 33 (1):  152-163.  DOI: 10.1016/S1872-2067(10)60290-2 Abstract ( 2903 )   [Full Text(HTML)] () PDF (1248KB) ( 1453 )   The framework silica to alumina ratio, the porosity, and the acidity properties of ultrastable Y zeolites prepared by ‘steaming’ and by the ‘sequential alkaline treatment and steaming’ of NaY zeolites are compared. The adaptability of the combined alkaline treatment method and steaming toward the type of starting NaY zeolites was studied. By comparison with single steaming treatment the combination of sequential alkaline treatment and steaming affords products with an obviously increased mesopore volume. The level of framework ultrastabilization and acidity of the final products were not affected. The mesopore volume of the ultrastable Y zeolite prepared by steaming dealumination only was no more than 0.14 cm3/g. The mesopore volume of the final product prepared by sequential desilication and dealumination was 0.22 cm3/g. The sequential desilication and dealumination method is suitable for the NaY zeolite with a high framework silica to alumina ratio. A small increase in the mesopore volume and severe micropore damage were evident when the NaY zeolite with a relatively low silica to alumina ratio (SiO2/Al2O3 = 4.8, determined by nuclear magnetic resonance) was used as the starting material for the combined desilication and dealumination treatment.

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Synthesis of Mesoporous Silicas with a Cationic Surfactant-Anionic Polymer Mixture as Template ZHANG Li-Na, WANG Hao, FAN Wei-Bin, WANG Jian-Guo 2012, 33 (1):  164-173.  DOI: 10.1016/S1872-2067(11)60344-6 Abstract ( 3224 )   [Full Text(HTML)] () PDF (1126KB) ( 1159 )   Different structural mesoporous silicas have been synthesized at high temperature using the Stöber method by utilizing a mixture of cationic cetyltrimethylammonium bromide and anionic water-soluble sodium polyacrylate (NaPAA) as template. The synthetic conditions, which include the amount of ethanol, crystallization temperature, crystallization time, polymer concentration, and molecular weight, have significant influence on the structures and surface morphologies of the synthetic product. This could be attributed to a combined effect of NaPAA and ethanol.

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Synthesis of SAPO-34 Molecular Sieves Templated with Diethylamine and Comparison with Other Templates LIU Guang-Yu, TIAN Peng, LIU Zhong-Min 2012, 33 (1):  174-182.  DOI: 10.1016/S1872-2067(11)60325-2 Abstract ( 2736 )   [Full Text(HTML)] () PDF (1047KB) ( 1047 )   SAPO-34 molecular sieves were synthesized using diethylamine (DEA) as a template. Influencing factors, such as H3PO4 content, H2O content, Al source, and Si source, were investigated. Pure SAPO-34 could be obtained under the following synthesis gel conditions: 0.7 ≤ n(P2O5)/n(Al2O3) ≤ 1.2 and 25 ≤ n(H2O)/n(Al2O3) ≤ 100. The Al source has a great influence on the resulting sample composition. SAPO-34 could also be synthesized using triethylamine (TEA), morpholine (MOR), and a DEA-TEA mixture as template, respectively. The products were characterized using X-ray diffraction, X-ray fluorescence, scanning electron microscopy, thermogravimetry, and 29Si MAS NMR. The level of silicon incorporation into the SAPO-34 framework decreased in the following order of SAPO-34 (DEA) > SAPO-34 (MOR) > SAPO-34 (TEA). The Si(4Al) contents in the SAPO-34 frameworks followed the order of SAPO-34 (DEA) ≈ SAPO-34 (MOR) > SAPO-34 (TEA).

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Nanoscale ZSM-5 Zeolite for the Benzylation of Aromatic Hydrocarbons MIAO Hai-Xia, XUE Zhao-Teng, MA Jing-Hong, ZHANG Yuan-Chun, LI Rui-Feng 2012, 33 (1):  183-191.  DOI: 10.1016/S1872-2067(10)60301-4 Abstract ( 2745 )   [Full Text(HTML)] () PDF (494KB) ( 1067 )   ZSM-5 zeolite in the form of crystalline nanoclusters was synthesized from seeds functionalized by organosilane and its catalytic performance in the benzylation of aromatic hydrocarbon by benzyl chloride was investigated. The zeolite samples were characterized by X-ray diffraction, N2 adsorption-desorption, and scanning electron microscopy. The results indicated that they were composed of aggregates of nanocrystals about 20 nm. They had high external surface area that was five times that of conventional ZSM-5. The amounts of acid sites were increased, which was indicated by acidity characterization by the Fourier transform infrared spectroscopy of adsorbed pyridine and temperature-programmed desorption of NH3. Moreover, accessibility to the acid sites was improved by reducing the size of crystals to nanoscale. In the benzylation of aromatics by benzyl chloride, nanoscale ZSM-5 showed a much higher activity than conventional ZSM-5 because the diffusional limitation for the large reactant was decreased in the nanoscale ZSM-5 zeolite. The benzyl chloride conversion in the benzylation of toluene was 98% at 363 K for 10 h, which was 3.6 times higher than that over conventional ZSM-5. The apparent rate constant over the nanoscale ZSM-5 zeolite was ca. 13 times larger than that over conventional ZSM-5.

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Recystallization of HCl-Treated Y Zeolite with Short Range Order SONG Yan-Mei, REN Nan, TANG Yi 2012, 33 (1):  192-198.  DOI: 10.3724/SP.J.1088.2012.10828 Abstract ( 2339 )   [Full Text(HTML)] () PDF (606KB) ( 849 )   A series of acid-treated Y zeolite crystals with different crystallinities were obtained by treating commercial Y zeolite in HCl solution. The acid-treated Y zeolites were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and 27Al and 29Si MAS NMR. The results indicated that the acid-treated Y zeolites were almost amorphous but some short-range-order aluminosilicate species were retained. The acid-treated Y zeolites were recrystallized at 150 oC with 0.3 mol/L NaOH solution by the steam-assist crystallization method, and the pure mordenite zeolite products with the morphology from aggregate of nano-rod to micron-sized crystal were obtained within a suitable Si/Al ratio range. Their BET surface area is higher than 400 m2/g and micropore volume is up to 0.19 cm3/g.

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Multi-step Dealumination and Incorporation of Titanium into the Framework of Natural Mordenite toward a Titanosilicate Catalyst XIAO Li-Ping, YANG Jing, ZHOU Hui, CHEN Chun-Yu, SUN Shi-Ye, LOU Hui, ZHENG Xiao-Ming 2012, 33 (1):  199-204.  DOI: 10.3724/SP.J.1088.2011.10827 Abstract ( 2458 )   [Full Text(HTML)] () PDF (490KB) ( 955 )   Titanosilicates with low cost have been prepared via multi-step incorporation of titanium into natural mordenite (MOR) using natural MOR as the precursor. The resultant Ti-MOR was characterized by X-ray diffraction, inductive coupled plasma-atomic emission spectroscopy, diffused reflectance ultraviolet-visible spectroscopy, N2 adsorption-desorption, and temperature-programmed desorption of ammonia. The results showed that the framework of natural MOR remained during the treatment and the molar ratio of Si to Ti was low to 79. Furthermore, the well-dispersed 4-coordinated Ti was confirmed by UV-Vis spectra and the titanosilicate displayed appreciable activity in the selective oxidation of styrene using dilute H2O2 (30%) as oxidant.