- 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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- Efficient cross-coupling of aryl/alkenyl triflates with acyclic secondary alkylboronic acids
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Aryl-secondary alkyl cross-coupling with aryl sulfonate esters as coupling partners remains a significant challenge. Efficient cross-coupling between aryl/alkenyl triflates and acyclic secondary alkylboronic acids is realized for the first time to provide a series of sterically congested acyclic secondary alkyl arenes/olefins in good to excellent yields. The employment of sterically bulky P,PO ligand L1/L2 is crucial for the high yields and selectivities. The method has enabled a concise and 4-step synthesis of a key intermediate of male contraceptive agent and PAF antagonist gossypol.
- Si, Tengda,Li, Bowen,Xiong, Wenrui,Xu, Bin,Tang, Wenjun
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supporting information
p. 9903 - 9909
(2017/12/12)
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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 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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- Efficient synthesis of sterically hindered arenes bearing acyclic secondary alkyl groups by suzuki-miyaura cross-couplings
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Bulky P,P-O ligands were designed to inhibit isomerization and reduction side reactions during the cross coupling between sterically hindered aryl halides and alkylboronic acids. Suzuki-Miyaura cross-couplings between di-ortho-substituted aryl bromides and acyclic secondary alkylboronic acids have been achieved with high yields. The method has also enabled the preparation of ortho-alkoxy di-ortho-substituted arenes bearing isopropyl groups in excellent yields. The utility of the synthetic method has been demonstrated in a late-stage modification of estrone and in the application to a new synthetic route toward gossypol. No side reaction: The shown bulky P,P-O ligands (right) successfully inhibit isomerization and reduction side reactions of the cross-coupling of sterically hindered substrates such as di-ortho-substituted aryl bromides with acyclic secondary alkylboronic acids. The method also allows the preparation of ortho-alkoxy di-ortho-substituted isopropyl arenes in excellent yields.
- Li, Chengxi,Chen, Tianyu,Li, Bowen,Xiao, Guolan,Tang, Wenjun
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supporting information
p. 3792 - 3796
(2015/03/18)
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- High-silica nanocrystalline Beta zeolites: Efficient synthesis and catalytic application
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An efficient synthesis methodology to obtain homogeneous nanosized high-silica Beta zeolites (~10-20 nm) with high solid yields (above 95%) using simple alkyl-substituted flexible dicationic OSDAs is described. These dicationic OSDAs allow the synthesis o
- Martínez-Franco, Raquel,Paris, Cecilia,Martínez-Armero, Marta E.,Martínez, Cristina,Moliner, Manuel,Corma, Avelino
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p. 102 - 108
(2015/12/30)
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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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- 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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- 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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- 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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- 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 5-6
(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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- 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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- 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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- Selective Mono-Alkylation and Arylation of Dichlorobenzenes by Palladium-Catalyzed Grignard Cross-Coupling
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Palladium(II)-phosphine complexes, especially PdCl2(dppf) where dppf stands for 1,1'-Bis(diphenylphosphino)ferrocene, are effective catalysts for the cross-coupling of Grignard reagents with dichlorobenzenes to produce selectively mono-alkylated and arylated benzenes.The addition of ligands is also effective for the cross-coupling of Grignard reagents containing a β-hydrogen(s).
- Katayama, Tatsuo,Umeno, Masayuki
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p. 2073 - 2076
(2007/10/02)
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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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- Alkylation or aromatic compounds
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Improved catalytic process for the alkylation of aromatic substrates, the improved process characterized in that the catalyst is a metal cation salt of a perfluorosulfonic acid polymer having an equivalent weight of about 500 to about 20,000, the metal cation having a log K11 greater than -10.
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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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- Influence of Conditions of Preparation of Aluminium Silicates on Their Catalytic Activity in Alkylations. I. Effects of pH and Temperature of Hydrolysis
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Results are presented on the effects of the pH and temperature of cohydrolysis of tetraethoxysilane and aqueous aluminium nitrate on the properties of sodium-free aluminium silicates and their catalytic activity in the alkylation of benzene by propene and
- Kolesnikov, I. M.,Grinis, L. M.
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p. 260 - 262
(2007/10/02)
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- STUDY OF THE CHEMICAL COMPOSITION, ACIDITY, AND ACTIVITY OF ALUMINOSILICATE CATALYSTS IN ALKYLATION REACTIONS
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The connection between the chemical composition, acidity, and activity of aluminosilicate catalysts in the alkylation of benzene by propylene has been studied. The total conversion of propylene and the yield of isopropylbenzene depends on the acidity strength while the yield of realkylation products and the isometric composition of these products depends on the total content of acidic centers on the surface of the catalyst.
- ZUL'FUGAROV ZG,BAKHSHI-ZADE AA,ZUL'FUGAROV LSH,SMIRNOVA NA,PIS'MAN II
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p. 749 - 751
(2007/10/13)
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