- Stabilizing Low-Silica Zeolites through Aluminum Sulfate Assisted Cannibalistic Dealumination
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A versatile dealumination strategy was proposed to stabilize low-silica zeolites through cannibalistic interaction between the host framework Al (FAL) and the guest aluminum salt. It is possible to capture selectively the FAL and Na ions in NaY zeolite by employing a special external Al source such as aluminum sulfate as the dealuminating agent. This unique postmodification reduces the FAL amount efficiently and converts the chemically reacted Al species into a γ-alumina support for the catalytically active component of zeolite, which avoids wasting Al sources. Possessing greatly enhanced hydrothermal stability, newly generated intracrystal mesopores, as well as an optimized distribution of FAL, the resultant dealuminated Y zeolite catalysts can be used practically in heavy oil cracking.
- Shi, Zongbo,Ji, Peng,Zhu, Zhiguo,Jiang, Jin-Gang,Fu, Wenhua,Wu, Peng,Wang, Yimeng,He, Mingyuan
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Read Online
- Hierarchical MFI Zeolites with a Single-Crystalline Sponge-Like Mesostructure
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Single-crystalline sponge-like MFI mesoporous zeolites (SSMZs) have been synthesized by using bolaform surfactants with an axial chiral binaphthyl core in the hydrophobic tail and triquaternary ammonium head groups, as bifunctional organic structure-directing agents (OSDAs). By changing the length of alkyl chain between a triquaternary ammonium head group and a binaphthyl group from 4 to 10 carbons, SSMZs with high specific surface area (382–434 m2 g?1), abundant micropore-mesopore connectivity, and uniform mesopore diameter (4–10 nm) were obtained. OSDAs with an alkyl chain length of 11 and 12 carbons led to the formation of nanorod-constructed mesoporous MFI zeolites. A geometrical matching between the cylindrical arrangement of the binaphthyl groups and the zeolitic framework is speculated to be the key factor for the formation of mesoporous zeolites. The SSMZ zeolites, with abundant mesopores beneficial for the diffusion of reactants, exhibited significantly higher catalytic efficiencies than those of the conventional ZSM-5 with a microcrystal morphology (≈1.5 μm).
- Zhang, Yunjuan,Luo, Peng,Xu, Hao,Han, Lu,Wu, Peng,Sun, Huai,Che, Shunai
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supporting information
p. 19300 - 19308
(2018/11/27)
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- PROCESS FOR MAKING CUMENE BY ALKYLATION OF BENZENE USING AN ORGANOTEMPLATE-FREE ZEOLITE BETA
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A process for making cumene by the alkylation of benzene with propylene using a benzene alkylation catalyst that comprises an organotemplate-free zeolite beta having a silica-to-alumina molar ratio of less than 20 and synthesized without an organic structure directing agent (SDA).
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Paragraph 0079
(2017/04/23)
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- Self-Assembly of Cetyltrimethylammonium Bromide and Lamellar Zeolite Precursor for the Preparation of Hierarchical MWW Zeolite
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Construction of hierarchical zeolite catalysts from lamellar zeolite precursor is challenging and promising for industrial catalysis. Although numerous efforts have been dedicated to control the organization of zeolite nanosheets by postsynthetic approaches or employing complex surfactants in hydrothermal synthesis, there is still no successful case that the hierarchical lamellar zeolite is hydrothermally synthesized by the self-assembly of the commercially available simple surfactant cetyltrimethylammonium bromide (CTAB) and inorganic zeolite precursor. In traditional syntheses, the self-assembly of simple surfactants and the growth of microporous framework are hardly compatible from both thermodynamic and kinetic viewpoints, preferring to cause phase separation. Herein, we approach for the first time the hydrothermal synthesis of a mesostructured multilamellar zeolite ECNU-7P, consisting of an alternative stacking of inorganic MWW zeolite nanosheets and organic CTAB layers with large interlayer spacing (25 ?), by a zeolite seed and CTAB-assisted dissolution-recrystallization route. Correlated 2D 1H-29Si solid-state NMR, X-ray, electron microscopy, and rotation electron diffraction analyses provide molecular-level insights into the guest-host interactions between organic surfactant and inorganic framework during the self-assembly and structure evolution process. Moreover, the calcined Al-ECNU-7 possessing a hierarchical mesostructure proves to serve as a highly active, selective, and stable solid acid catalyst for triisopropylbenzene cracking as well as acylation of anisole.
- Xu, Le,Ji, Xinyi,Li, Shenhui,Zhou, Zhengyang,Du, Xin,Sun, Junliang,Deng, Feng,Che, Shunai,Wu, Peng
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p. 4512 - 4521
(2016/07/11)
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- A comparative study on catalytic performance of modified nanocrystalline and microcrystalline zeolite X for synthesis of cumene by transalkylation of 1,4-diisopropylbenzene with benzene
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Cumene is a commercially important product in the petrochemical industries. In isopropylation of benzene, 1,4-diisopropyl benzene (1,4-DIPB) is produced as low value by-product. This low value by-product DIPB is used to maximize the production of commercially important product cumene by transalkylation reaction. Reduction of crystal size in zeolite can increase surface area of the external surface and in this way bring about substantial changes in catalytic activity. Moreover modification with rare-earth metal enhances the acidity of zeolite. In this work, nanocrystalline and microcrystalline zeolite X were modified with cerium to study the combine effect of crystal size and ion modification of zeolite on selectivity of cumene in commercially important transalkylation reaction. Benzene and 1,4-diisopropylbenzene in a molar ratio of 1 to 12.5 were subjected to vapour-phase reaction in the temperature range of 498 to 593 K at atmospheric pressure with space time of 5.27–10.54 kg h/kmol. Nanosized crystalline zeolite gives much higher conversions of 1,4-DIPB than microcrystalline zeolite. Over cerium modified nanosized zeolite CeXN 81.85% conversion of 1,4-DIPB and 97% cumene selectivity were achieved. It was found that stability and activity of CeXN for cumene synthesis was much higher than that of CeXM zeolite. Kinetic constants for the reactions were estimated and the activation energies for various reactions over CeXM were determined. The activation enegy for transalkylation reaction was found to be 78.54 kJ/mol.
- Thakur,Barman
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p. 592 - 601
(2016/10/18)
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- A mesoporous aluminosilicate prepared by simply coating fibrous γ-AlOOH on the external surface of SBA-15 for catalytic hydrocarbon cracking
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A binary SiO2/Al2O3 composite with fibrous γ-alumina coating on the external surface of SBA-15 has been synthesized by simply mixing SBA-15 with fibrous boehmite sol, followed by aging and calcination. The textural and aci
- Shi, Zongbo,Guan, Yejun,Wu, Peng,He, Mingyuan
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p. 40296 - 40303
(2016/05/24)
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- Synthesis and properties of MFI zeolites with microporous, mesoporous and macroporous hierarchical structures by a gel-casting technique
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The comparatively small micropore dimensions of bulk ZSM-5 zeolites often limit both the adsorption and catalytic conversion of large organic molecules. Here, we report that ZSM-5 zeolites were prepared by a gel-casting technique with microporous, mesoporous and macroporous hierarchical structures. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, temperature-programmed-desorption of ammonia (TPD-NH3) and Fourier transform infrared spectroscopy (FTIR) measurements. The hierarchical structured ZSM-5 zeolites were used to carry out catalytic cracking of 1,3,5-triisopropyl benzene and n-hexadecane. The results show that, compared with traditional ZSM-5, Beta or Al-MCM-41, this modified ZSM-5 displayed preferable catalytic activity and selectivity.
- Wang, Ying,Wang, Runwei,Xu, Diou,Sun, Chuanyin,Ni, Ling,Fu, Weiwei,Zeng, Shangjing,Jiang, Shang,Zhang, Zongtao,Qiu, Shilun
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supporting information
p. 4398 - 4405
(2016/06/09)
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- A solvent evaporation route towards fabrication of hierarchically porous ZSM-11 with highly accessible mesopores
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A route to generate hierarchically porous zeolite ZSM-11 has been paved via solvent evaporation induced self-assembly assisted by hexadecyltrimethoxysilane to produce a preformed dry gel, followed by its subsequent transformation into zeolite via steam-assisted-crystallization. The crystallization in dry gel has been found to undergo an orientated attachment growth mechanism whereby hexadecyltrimethoxysilane directs the formation of auxiliary mesopores and inhibits the fusion of primary nucleates. Measurements such as XRD, SEM, TEM, N2-physisorption, and TEM for an inverse replica of Pt derived from hierarchical ZSM-11 have been conducted to characterize the textural properties of the material. Ammonia temperature-programmed-desorption (NH3-TPD) measurements and infrared spectra using probe molecules such as pyridine (Py-IR) and 2,4,6-collidine (Coll-IR) have been collected to investigate the acidic properties as well as the accessibility of the acid sites. The hierarchical ZSM-11 possesses more acid sites on the mesopore surfaces that are accessible towards large probe molecules such as 2,4,6-collidine. This improvement together with the enhanced pore-connectivity brings about an increase in 1,3,5-triisopropylbenzene cracking activity and benzene selectivity with respect to a conventional counterpart.
- Song, Wen,Liu, Zhiting,Liu, Liping,Skov, Anne Ladegaard,Song, Nan,Xiong, Guang,Zhu, Kake,Zhou, Xinggui
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p. 31195 - 31204
(2015/04/22)
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- A facile approach for the preparation of tunable acid nano-catalysts with a hierarchically mesoporous structure
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A facile and efficient approach to prepare hierarchically and radially mesoporous nano-catalysts with tunable acidic properties has been successfully developed. The nanospheres show excellent catalytic performance for the acid catalysed reactions, i.e. cr
- Choi, Youngbo,Yun, Yang Sik,Park, Hongseok,Park, Dae Sung,Yun, Danim,Yi, Jongheop
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supporting information
p. 7652 - 7655
(2014/07/08)
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- An active, general, and long-lived palladium catalyst for cross-couplings of deactivated (hetero)aryl chlorides and bromides with arylboronic acids
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An active, general, and long-lived palladium catalyst for Suzuki-Miyaura reactions of aryl and heteroaryl chlorides deactivated by steric hindrance, electron richness, and coordinating functional groups is reported. In reactions of arylbromide bearing two o-tert-butyl substituents, C(sp3)-H arylation of the tert-butyl group, rather than the Suzuki-Miyaura reaction, proceeded in excellent yield. The key to the success of the reactions was the development of biphenylene-substituted dicyclohexylruthenocenylphosphine (CyR-Phos) as a supporting ligand.
- Hoshi, Takashi,Honma, Tomonobu,Mori, Ayako,Konishi, Maki,Sato, Tsutomu,Hagiwara, Hisahiro,Suzuki, Toshio
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p. 11513 - 11524
(2013/12/04)
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- Benzene reduction in gasoline by alkylation with olefins: Comparison of Beta and MCM-22 catalysts
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The study compares the performance of Beta and MCM-22 zeolites as catalysts for propylene alkylation of benzene present in an enriched sample of reformate heart cut (20 wt% benzene). The experiments were carried out in a batch system with a 2/1 mole ratio
- Laredo, Georgina C.,Castillo, J. Jesus,Navarrete-Bola?os, Juan,Perez-Romo, Patricia,Lagos, Flavio A.
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experimental part
p. 140 - 148
(2012/03/26)
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- Well-organized zeolite nanocrystal aggregates with interconnected hierarchically micro-meso-macropore systems showing enhanced catalytic performance
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Preparation and characterization of well-organized zeolitic nanocrystal aggregates with an interconnected hierarchically micro-meso-macro porous system are described. Amorphous nanoparticles in bimodal aluminosilicates were directly transformed into highly crystalline nanosized zeolites, as well as acting as scaffold template. All pores on three length scales incorporated in one solid body are interconnected with each other. These zeolitic nanocrystal aggregates with hierarchically micro-meso-macroporous structure were thoroughly characterized. TEM images and 29Si NMR spectra showed that the amorphous phase of the initial material had been completely replaced by nanocrystals to give a micro-meso-macroporous crystalline zeolitic structure. Catalytic testing demonstrated their superiority due to the highly active sites and the presence of interconnected micro-meso-macroporosity in the cracking of bulky 1,3,5-triisopropylbenzene (TIPB) compared to traditional zeolite catalysts. This synthesis strategy was extended to prepare various zeolitic nanocrystal aggregates (ZSM-5, Beta, TS-1, etc.) with well-organized hierarchical micro-meso-macroporous structures.
- Yang, Xiao-Yu,Tian, Ge,Chen, Li-Hua,Li, Yu,Rooke, Joanna C.,Wei, Ying-Xu,Liu, Zhong-Min,Deng, Zhao,Van Tendeloo, Gustaaf,Su, Bao-Lian
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scheme or table
p. 14987 - 14995
(2012/02/06)
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- Influence of mesoporous materials containing ZSM-5 on alkylation and cracking reactions
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In order to increase the yield of cymene in alkylation of toluene with isopropanol, ZSM-5 zeolite units were incorporated into a mesostructured material. The catalysts were characterized by X-ray diffraction, TGA, SEM, NH3 temperature-programmed desorption and FTIR of pyridine adsorption. XRD analysis indicated that a structurally well ordered cubic MCM-48 aluminosilicate was successfully assembled from ZSM-5 zeolite seeds. The ZSM-5/MCM-48 catalyst exhibited significantly improved toluene conversion and yield of cymene product for toluene isopropylation. Catalytic tests show that the ZSM-5/MCM-48 composite material exhibits high catalytic activity compared with the conventional Y-zeolite for catalytic cracking of 1,3,5- triisopropylbenzene (TIPB). The exceptional catalytic performance of ZSM-5/MCM-48 catalyst in cracking and alkylation reaction was attributed to the easier access of active sites provided by the mesopores for both reactant and larger product molecules. The apparent activation energies for the cracking of 1,3,5-TIPB over ZSM-5/MCM-48 catalyst were found to decrease as follows: E C/CM-3 (tertiary cracking) > E C/CM-4 (disproportionation) > E C/CM-2 (secondary cracking) > E C/CM-1 (primary cracking).
- Odedairo,Balasamy,Al-Khattaf
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experimental part
p. 21 - 36
(2011/10/05)
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- Sequential Birch reaction and asymmetric Ir-catalyzed hydrogenation as a route to chiral building blocks
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A range of 1,2,4-trisubstituted cyclohexadienes obtained from the Birch reaction were hydrogenated asymmetrically to produce synthetically valuable chiral compounds in high enantio- and diastereoselectivity. The Royal Society of Chemistry.
- Paptchikhine, Alexander,Itto, Kaori,Andersson, Pher G.
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supporting information; experimental part
p. 3989 - 3991
(2011/06/09)
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- Mesoporous mordenites obtained by sequential acid and alkaline treatments - Catalysts for cumene production with enhanced accessibility
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Two commercially available mordenites, obtained from Zeolyst (Si/Al = 10 at/at) and BASF (Si/Al = 8 at/at), were subjected to post-synthesis treatments. The impact of acid treatment, alkaline treatment (desilication) and a combination of both on porosity,
- Van Laak, Adri N.C.,Sagala, Sophia L.,Zecevic, Jovana,Friedrich, Heiner,De Jongh, Petra E.,De Jong, Krijn P.
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experimental part
p. 170 - 180
(2011/02/23)
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- Direct synthesis of carbon-templating mesoporous ZSM-5 using microwave heating
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Carbon-templated mesoporous ZSM-5 zeolites were synthesized directly avoiding a drying process. Carbon nanoparticles were simply mixed into synthesis precursor of ZSM-5 and hydrothermally treated by microwave irradiation. The amount of mesopores formed inside the ZSM-5 single crystals was controllable by adjusting the amount of carbon used. For comparison, mesoporous ZSM-5 zeolites have also been synthesized under hydrothermal conditions. The influence of microwave irradiation on mesoporous ZSM-5 materials was thoroughly investigated by using nitrogen adsorption/desorption studies and 27Al MAS NMR. The nature of acid sites both in the micropores (internal) and on the surface of mesopores (external) was investigated by in situ FTIR spectroscopy using pyridine (Py) and 2′,6′-di-tert-butylpyridine (DTBPy) as a probe molecules. Mesoporous ZSM-5 prepared by microwave synthesis showed higher catalytic activity in the bulky molecular reaction of 2′,4′- dimethoxyacetophenone (2′,4′-DMAP) with 4-methoxybenzaldehyde as a model reaction in comparison with the results obtained over hydrothermally prepared ZSM-5. The further catalytic behavior has been studied in condensation reaction and cracking of substituted benzene.
- Koo, Jeong-Boon,Jiang, Nanzhe,Saravanamurugan, Shunmugavel,Bejblova, Martina,Musilova, Zuzana,Cejka, Jiri,Park, Sang-Eon
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experimental part
p. 327 - 334
(2011/02/27)
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- Heteropolyacid salt catalyst, process for producing heteropolyacid salt catalyst and process for producing alkyl aromatic compound
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The present invention provides a heteropolyacid salt catalyst for use in an alkylation reaction of an aromatic compound or a transalkylation, disproportionation or isomerization reaction of an alkyl aromatic compound, which comprises a heteropolyacid salt
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Page/Page column 7
(2009/09/05)
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- Development of a supported ionic liquid phase (SILP) catalyst for slurry-phase friedel-crafts alkylations of cumene
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A supported ionic liquid phase (SILP) catalyst material has been developed based on a silica support coated with an acidic chloroaluminate ionic liquid. Compared to the results in a liquid-liquid biphasic reaction these materials showed in the isopropylat
- Joni,Haumann,Wasserscheid
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experimental part
p. 423 - 431
(2009/11/30)
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- METHOD FOR PRODUCING ALKYLATED AROMATIC COMPOUND AND METHOD FOR PRODUCING PHENOL
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The present invention provides an industrially practical process where a ketone and an aromatic compound are directly reacted to obtain a corresponding alkylated aromatic compound in a single reaction step. The process for producing an alkylated aromatic compound is characterized in that it comprises reacting an aromatic compound, a ketone and hydrogen in the presence of a solid acid substance and a catalyst composition comprising at least one metal selected from the group consisting of Co, Re, Ni and a platinum group metal.
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Page/Page column 7
(2009/10/01)
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- Detailed kinetic study of cumene isopropylation in a liquid-liquid biphasic system using acidic chloroaluminate ionic liquids
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A kinetic study of cumene isopropylation has been carried out using the acidic ionic liquid 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl)/AlCl3 (molar ratio 1:2) as the catalyst phase in a semi-batch liquid-liquid biphasic reaction system. Kinetic models representing the alkylation reaction network have been established based on reaction temperature and propylene partial pressure variations. By comparing the results of the kinetic models with the measured concentrations in the liquid organic phase, the importance of the different product solubilities in the acidic ionic liquid became evident. Correction of the product concentrations in the organic phase based on a COSMO-RS calculation of the relative product solubilities in the acidic ionic liquid [EMIM][Al2Cl7] gave a remarkably good prediction of the reaction kinetics by the kinetic model. These findings demonstrate the suitability of COSMO-RS to predict the relative solubilities of different aromatic compounds in highly reactive catalytic systems.
- Joni,Schmitt,Schulz,Lotz,Wasserscheid
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experimental part
p. 401 - 409
(2009/03/11)
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- Synthesis methodology, stability, acidity, and catalytic behavior of the 18 × 10 member ring pores ITQ-33 zeolite
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We used a flexible organic structure-directing agent (OSDA) and high-throughput (HT) synthesis techniques to explore a large composition region. A zeolite with the largest pores reported to date (ITQ-33) was found under very unusual synthesis conditions, together with other known structures. A second HT experimental design allowed, finally synthesizing pure ITQ-33. We studied the thermal and hydrothermal stability and acid properties of the zeolite. We investigated the role of pore diameter on zeolite acid strength by comparing the 18-ring pore (ITQ-33) with a 12-MR pore (ITQ-17) zeolite with the same framework composition. Finally, we compared the catalytic properties of ITQ-33 for reactant molecules of different sizes with those of 12-MR (Beta) and 14-MR (UTD-1) zeolites.
- Moliner, Manuel,Diaz-Cabanas, Maria J.,Fornes, Vicente,Martinez, Cristina,Corma, Avelino
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p. 101 - 109
(2008/09/17)
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- Selective alkylation of aromatic hydrocarbons
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A method for increasing selectivity of alkylation to monoalkylation comprising: providing a feedstream consisting essentially of alkylating agent and a stoichiometric excess of benzene, the alkylating agent consisting essentially of a molar blend of propylene and one or more linear butene(s); and, contacting the feedstream with a catalytically effective amount of zeolite beta under alkylation reaction conditions which increase selectivity of the alkylation to monoalkylation compared to predicted selectivity to monoalkylation based on the concentration of the alkylating agent and on the molar blend of propylene and one or more linear butene(s).
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Page/Page column 6; 7
(2008/06/13)
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- Catalytic cracking of large molecules over hierarchical zeolites
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A hierarchical zeolite catalyst was synthesized by transforming the skeletons of a bimodal pore silica gel into a zeolite through a steam-assisted conversion method, and shows high catalytic activity and a long catalyst lifetime for catalytic cracking of large molecules. The Royal Society of Chemistry 2006.
- Lei, Qian,Zhao, Tianbo,Li, Fengyan,Zhang, Ling,Wang, Yue
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p. 1769 - 1771
(2008/09/17)
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- In situ synthesis, characterization of SiPMo-X, and different catalytic properties of SiPMo-X and SiPW-X
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SBA-15 frameworks with encapsulated Keggin type heteropolyacids (HPAs) were synthesized in situ under strongly acidic conditions (pH 2 adsorption-desorption isotherms and transmission electron microscopy (TEM), and their structure was systematically characterized by X-ray diffraction (XRD), UV/Vis diffuse reflectance-(DRS), infrared- (IR), and 31P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. Characterization results suggest that the samples show very ordered hexagonal mesostructure, and the HPAs that are incorporated into the framework of meso-silica are insoluble during catalysis. Results of catalytic tests indicate that the materials demonstrated catalytic activity comparable with or even surpassing those of the bulk HPAs in catalytic tests implementing chemical reactions of bulky molecules (1,3,5-tri-isopropylbenzene cracking, esterification of benzoic acid with tert-butyl alcohol, and 2,3,6-trimethylphenol hydroxylation with H 2O2). Additionally, some other properties, such as easy separation and stability when recycled, ensure their potential applications in the chemical industries. Here, we report not only the in situ synthesis and characterization of SiPMo-X, but also the difference in the catalytic properties of SiPMo-X and SiPW-X. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Shi, Chunfeng,Wang, Runwei,Zhu, Guangshan,Qiu, Shilun,Long, Jun
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p. 3054 - 3060
(2007/10/03)
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- Biosynthesis of phloroglucinol
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Substantial concentrations of phloroglucinol were synthesized by Pseudomonas fluorescens Pf-5 expressing the plasmid-localized phlACBDE gene cluster responsible for biosynthesis of 2,4-diacetylphloroglucinol. Expression in Escherichia coli of a single gene in this cluster, P. fluorescens Pf-5 phlD, led to extracellular accumulation of phloroglucinol. Purification of PhlD to homogeneity afforded an enzyme that catalyzed the conversion of malonyl-CoA into phloroglucinol with Km = 5.6 μM and kcat = 10 min-1. Acetylase and deacetylase activities were observed with the catalyzed interconversions of phloroglucinol, 2-acetylphloroglucinol, and 2,4-diacetylphloroglucinol when phlACB was expressed in E. coli. Beyond the mechanistic implications attendant with the identification of an enzyme that catalyzes the conversion of malonyl-CoA into phloroglucinol, PhlD provides the basis for environmentally benign syntheses of phloroglucinol and resorcinol from glucose. Copyright
- Achkar, Jihane,Xian, Mo,Zhao, Huimin,Frost
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p. 5332 - 5333
(2007/10/03)
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- Process for synthesizing diisopropylbenzene
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This invention relates to a process for synthesizing para-diisopropylbenzene utilizing only cumene and propylene as raw materials. This synthesis technique offers the advantage of eliminating benzene as a raw material used in the process. The elimination of benzene is beneficial because it simplifies the process and eliminates the need to purchase and store benzene for use in the synthesis. The elimination of benzene from the synthesis is of particular value since the use of benzene in industrial applications has been under attack on the basis of environmental, safety, and health concerns. The present invention discloses a process for producing para-diisopropylbenzene from cumene and propylene, said process comprising the steps of (1) introducing a feed stream into an alkylation zone wherein said feed stream is comprised of cumene and propylene, and wherein said alkylation zone contains an alkylation catalyst; (2) allowing the cumene and propylene in the feed stream to react together to produce a first mixture of para-diisopropylbenzene and meta-diisopropylbenzene; (3) fractionally distilling the mixture of para-diisopropylbenzene and meta-diisopropylbenzene in a fractional distillation step to separate the meta-diisopropylbenzene from the para-diisopropylbenzene; (4) isomerizing the meta-diisopropylbenzene in the presence of a transalkylation catalyst to produce a second mixture of para-diisopropylbenzene and meta-diisopropylbenzene; (5) recycling the second mixture of para-diisopropylbenzene and meta-diisopropylbenzene recovered from the transalkylation step to the fractional distillation step; and (6) recovering the para-diisopropylbenzene that was separated from the meta-diisopropylbenzene by the fractional distillation step.
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Page/Page column 4
(2008/06/13)
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- PRODUCTION OF META-DIISOPROPYLBENZENE
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A process for the selective production of meta-diisopropylbenzene is disclosed, wherein the process comprises the steps of contacting cumene under disproportionation conditions and in the absence of added benzene with a catalyst comprising a porous crysta
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- Process for aromatics alkylation employing zeolite beta prepared by the in-extrudate method
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A process for the alkylation of an aromatic hydrocarbon which comprises contacting the aromatic hydrocarbon with an C2-C4 olefin alkylating agent under at least partial liquid phase conditions, in the presence of a catalyst comprisin
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Page/Page column 3-4
(2008/06/13)
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- Isopropylation of benzene in the vapour phase over zeolite beta modified by lanthanum, cerium, gallium and zinc
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Zeolite beta has been synthesized with varying Si/Al ratio. Beta-15 has been modified by La3+, Ce3+, Ga3+and Zn2+and characterized by physico-chemical analysis. Isopropylation of benzene with isopropanol has been done in a fixed bed flow type reactor under different experimental conditions and the products analysed by G.C. The influences of cations, aluminium content, reaction and calcination temperatures, space velocity, molar ratio of benzene to isopropanol (IPA) and time on stream (TOS) on the activity and selectivity to cumene and di-isopropylbenzene (DIPB) have been investigated and discussed.
- Gnanapragasam,Krishnasamy,Mohan
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p. 947 - 952
(2007/10/03)
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- Thermolysis of free-radical initiators: tert-butylazocumene and its 1,3- and 1,4-bisazo and 1,3,5-trisazo analogues
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Four tert-butylazocumenes (4-7) were prepared from the corresponding cyanobenzenes, and their nitrogen evolution kinetics and products were analyzed. In combination with TEMPO, the simplest compound, tert-butylazocumene (4), shows promise as a "one-radical" initiator of styrene polymerization. The ABNO-trapped cumyl radical 29 is a particularly stable trialkylhydroxylamine, whose thermolysis half-life is 2.1 h at 150 °C. Taking advantage of this stability, we trapped the cumyl radical centers from 7 to afford tris adduct 32a. While the behavior of the meta bisazoalkane 6 can be mostly predicted from that of 4, the para isomer 5 exhibits both unusual products and kinetics, attributed to the formation of quinodimethane 33 via azo-containing radical 34. In fact, flash vacuum pyrolysis of 5 allowed observation of the 1H and 13C NMR spectra of 33, whose persistence even at ambient temperature showed that this quinodimethane is far more stable than the parent 36. Finally, evidence is presented that 7 is an initiator of star polymerization.
- Engel,Pan,Ying,Alemany
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p. 3706 - 3715
(2007/10/03)
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- Alkylation of benzene with short-chain olefins over MCM-22 zeolite: Catalytic behaviour and kinetic mechanism
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Cumene and ethylbenzene are important compounds in the petrochemical industry for the production of phenol and styrene, respectively. Cumene and ethylbenzene are produced by benzene alkylation with propylene and ethylene. Benzene alkylation with ethylene
- Corma,Martinez-Soria,Schnoeveld
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p. 163 - 173
(2007/10/03)
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- Contributions of enthalpy and entropy factors to isomerization equilibrium of isopropyl- and cyclohexylbenzenes
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Experimental and theoretical data on the liquid-phase equilibrium of the positional isomerization of isopropyl- and cyclohexylbenzenes are analyzed in detail. Contributions of the enthalpy and entropy factors to the equilibrium constants of the ortho-meta and para-meta transformations are estimated.
- Nesterova,Pimerzin,Krasnykh
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p. 1884 - 1890
(2007/10/03)
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- The effect of cyclic dealumination on the catalytic activity of beta zeolite
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The acidity of zeolite beta is decreased by dealumination with (NH4)2SiF6 The effect of change in zeolite acidity on catalytic activity for benzene isopropylation has been studied. The reasons for change in the product pat
- Das,Bhat,Halgeri
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p. 690 - 692
(2007/10/03)
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- The effect of acidity of Al and Fe silicates with MFI structure on benzene and toluene alkylation with isopropyl alcohol
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Kinetic study of toluene and benzene alkylation with isopropyl alcohol on alumo-and ferrisilicates of MFI structure has shown that the alkylation activity does not follow the acidity (both the number and strength of bridging OH groups) of these molecular sieves. The rate of the overall reaction is controlled by the desorption/transport rate of bulky, strongly adsorbed cymenes and cumene. A higher concentration of n-propyltoluenes compared to n-propylbenzene, both undesired reaction products, formed via a bimolecular isomerization of isopropyl aromate with benzene or toluene, was due to the higher reactivity of isopropyltoluene with toluene in comparison with that of cumene with benzene. It is concluded that ferrisilicates of MFI structure possessing low strength acid sites appear to be promising catalysts for achieving both a high isopropyl-and para-selectivity in toluene alkylation to p-cymene.
- Cejka, Jiri,Zilkova, Nadezda,Wichterlova, Blanka
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p. 1115 - 1130
(2007/10/03)
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- Aprotic diazotization in the presence of cuprous cyanide
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In a procedure of extreme simplicity and rapidity a mixture of an aromatic primary amine, copper (I) cyanide and an alkyl nitrite in dimethyl sulphoxide yielded fair to moderate yields of the corresponding nitriles. Side processes observed were reduction (NH2&[H), nitration (NH2←NO2) and hydroxylation (NH2&[OH). In the case of polyhaloanilines halogen dance products could be detected.
- Giumanini, Angelo G.,Verardo, Giancarlo,Geatti, Paola,Strazzolini, Paolo
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p. 7137 - 7148
(2007/10/03)
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- Hydrocarbons and chloroaromatics from anilines and n-butyl nitrite
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A single reagent, i.e. n-butyl nitrite, can be used to oxidize an aromatic amine, or the corresponding N-methylene derivative, to a diazo compound followed by its subsequent reduction to hydrocarbon in a single batch.Alternatively, a chloro derivative can be obtained if carbon tetrachloride is used as the solvent.The reactions appear to be general and complete product identification was accomplished.
- Giumanini, Angelo G.,Verardo, Giancarlo,Gorassini, Fausto,Strazzolini, Paolo
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p. 311 - 316
(2007/10/02)
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- Isopropylation of Benzene with 2-Propanol over High-Silica Large-Pore Zeolite: NCL-1
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The influence of various reaction parameters such as temperature, WHSV, time on stream, and feed ratio of benzene to 2-propanol, as well as of the Si/Al molar ratio of zeolite NCL-1, on catalytic activity and selectivity was studied in the isopropylation
- Sasidharan, M.,Reddy, K. Ramesh,Kumar, Rajiv
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p. 216 - 221
(2007/10/03)
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- Hydroperoxidation of diisopropylbenzene
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m-Diisopropylbenzene dihydroperoxide is produced in good yield in a continuous process by the oxidation of diisopropylbenzene, comprised of major amounts of the m-isomer and less than 6% of the o-isomer, under anhydrous, non-alkaline conditions with oxygen or air at about 85° C.-95° C.
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- Synthesis of tetrakis(2,6-diisopropylphenyl)digermene and its reductive cleavage to the corresponding digermenyllithium-(DME) complex
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Tetrakis(2,6-diisopropylphenyl)digermene is synthesized directly from bis(2,6-diisopropylphenyl)dichlorogermane by reductive coupling with lithium naphthalenide in dimethoxyethane (DME).Its structural integrity (double bond) is retained in solution and addition of methanol leads to 1-methoxy-1,1,2,2-tetrakis(2,6-diisopropylphenyl)digermane.Treatment of the digrermene with further equivalents of lithium naphthalenide in DME provided a novel digermenyllithium species.
- Park, Jaiwook,Batcheller, Scott A.,Masamune, Satoru
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- MECHANISM OF THE ALKYLATION OF BENZENE WITH PROPYLENE IN THE PRESENCE OF AN ALUMINOSILICATE CATALYST MODIFIED BY REACTION OF ALUMINUM CHLORIDE WITH AROMATIC HYDROCARBONS. CATALYST PROMOTION.
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Investigation of the kinetics of alkylation of benzene with propylene in the presence of an aluminum chloride-isopropylbenzene complex, an aluminosilicate catalyst, and modified aluminosilicate catalysts has established that catalyst activity is enhanced
- Kolesnikov,Zaitseva
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p. 754 - 760
(2007/10/02)
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- A meta-Xylylene by Bamford-Stevens-Reaction of a Fulvene-Ketene-Adduct
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Heating the sodium salt 8 of the tosylhydrazone 4 of 4-isopropyliden-7,7-dimethylbicyclohept-2-en-6-one (3; obtained by the addition of dimethylketene to 6,6-dimethylfulvene (1)), in diglyme at 130 deg C led to the octamethyl-metacyclophane 10 (17 percent).The latter probably was formed by dimerization of the non-Kekule molecule m-xylylene 14, which, in turn, could have arisen via the homofulvene 13 from the carbene 12.A second product in the thermolysis of 8 was the tricycle 9 (9 percent), as a result of an intramolecular insertion of the carbene C-atom in 12 into a methyl C,H-bond.Further products were the azines 11a, 11b (50 percent), of the type known as byproducts in Bamford-Stevens reactions.Heating dry 8 afforded 9 (9 percent) and the two benzene derivatives 15 (9 percent) and 16 (3 percent).The tosylhydrazone 4 could be recovered by reaction of 11a, 11b with p-toluenesulfonohydrazide.
- Stadler, Heinz,Rey, Max,Dreiding, Andre S.
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p. 1379 - 1385
(2007/10/02)
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- Dialkylthioxanthones
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The present invention relates to a dialkylthioxanthone compound of formula (I): STR1 wherein X and Y may be the same or different, and represent a straight-chain or branched alkyl group having 1-12 carbon atoms with a proviso that sum of carbon atoms of alkyl groups X and Y is in the range of 3-15; a process for producing said compound; a process for hardening a photopolymerizable resin compound having an ethylenically unsaturated double bond which is radically crosslinkable or polymerizable using the above compound; and a photopolymerizable resin composition containing the same.
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- Superacid catalyzed preparation of resorcinol from meta-diisopropylbenzene
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Resorcinol is prepared in high yield and purity by an improved process through superacid (such as perfluorinated alkanesulfonic acids of one to eighteen carbon atoms or polymeric perfluorinated resinsulfonic acids, such as acidified Nafion-H, catalyzed cleavage-rearrangement reaction of meta-bis(2-hydroperoxy-2-propyl)-benzene (meta-diisopropylbenzene dihydroperoxide). Part of the process is the preparation of needed meta-diisopropylbenzene in high purity (98-100%) substantially free of other isomers by treating any mixture of diisopropylbenzenes with an excess of anhydrous hydrogen fluoride or a perfluorinated alkanesulfonic acid of one to six carbon atoms and a Lewis acid fluoride, or by alkylating (transalkylating) cumene with a propyl alkylating agent in the aforementioned superacid systems.
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- The Influence of the Conditions of Synthesis of Aluminosilicates from Tetraethoxysilane and Aluminium Nitrate on Their Activity in the Alkylation Reaction. II. The Influence of the Sequence of Hydrolitic Reactions and the Drying Temperature
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The paper reports the physical properties and activities, in the alkylation of benzene by propene and butenes, of aluminosilicates synthesised using different sequences of hydrolytic reactions between tetraethoxysilane and an aqueous aluminium nitrate solution and different hydrogel drying temperatures.
- Kolesnikov, I. M.,Grinis, L. M.
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p. 276 - 277
(2007/10/02)
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- Method of recovering dialkylbenzene dihydroperoxide
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Separation of diisopropylbenzene dihydroperoxide from a diisopropylbenzene oxidation reaction mixture by treating the reaction mixture with concentrated alkali metal hydroxide and recovering the alkali metal salt of diisopropylbenzene dihydroperoxide in high purity and good yield, and subsequently converting the salt to diisopropylbenzene dihydroperoxide.
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