- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- 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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- Effect of Binder Content on the Properties of Nanocrystalline Zeolite BEA-based Catalysts for Benzene Alkylation with Propylene
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Abstract: The effect of binder content (aluminum hydroxide) on the textural, acidic, and catalytic properties of nanocrystalline zeolite BEA-based catalysts for the alkylation of benzene with propylene has been studied. It has been shown that increasing binder content increases the volume of mesopores in the sample and decreases the volume of micro- and macropores. Increased binder content in the catalyst primarily results in a decrease in the concentration of weak acid sites, whereas the concentration of strong acid sites changes only slightly. The observed regularity is associated with the reaction of the binder and the zeolite during the preparation of the catalyst, as well as with the formation of new acid sites. It has been found that increasing binder content increases the mechanical strength of the granulated catalyst, but this is accompanied with a decrease of its catalytic activity and stability in the gas-phase alkylation of benzene with propylene. It has been shown that the optimal content of the Al2O3 binder in the catalyst is about 30 wt %. The sample with the optimal binder content has demonstrated a stable on-stream behavior in the liquid-phase reaction that occurred with 99.4 wt % alkylation selectivity, 91.1 wt % cumene selectivity at 100% propylene conversion. [Figure not available: see fulltext.]
- Andriako, E. P.,Bok, T. O.,Ivanova, I. I.
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p. 901 - 907
(2021/08/06)
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- Facile Hydrogenolysis of C(sp3)–C(sp3) σ Bonds
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The modification of benzylic quaternary, tertiary, and secondary carbon centers through palladium-catalyzed hydrogenolysis of C(sp3)–C(sp3) σ bonds is presented. When benzyl Meldrum's acid derivatives bearing quaternary benzylic centers are treated under mild hydrogenolysis conditions – palladium on carbon and atmospheric pressure of hydrogen – aromatics substituted with tertiary benzylic centers and Meldrum's acid are obtained with good to excellent yield. Analogously, substrates containing tertiary or secondary benzylic centers yield aromatics substituted with secondary benzylic centers or toluene derivatives, respectively. Furthermore, this strategy is used for the high yielding synthesis of diarylmethanes. The scope of the reductive dealkylation reaction is explored and the limitations with respect to steric and electronic factors are determined. A mechanistic analysis of the reaction is described that consisted of deuterium labelling experiments and hydrogenolysis of enantioenriched derivatives. The investigation shows that the C(sp3)–C(sp3) σ bond-cleaving events occur through a hybrid SN1/SN2 mechanism, in which the palladium center displaces a carbon-based leaving group, namely Meldrum's acid, with inversion of configuration, followed by reductive elimination of palladium to furnish a C?H bond. (Figure presented.).
- Fillion, Eric,Beaton, Eric,Nguyen, Yen,Wilsily, Ashraf,Bondarenko, Ganna,Jacq, Jér?me
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supporting information
p. 3422 - 3434
(2016/11/13)
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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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(2009/09/05)
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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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- Nickel-catalyzed cross-coupling reactions of alkyl aryl sulfides and alkenyl alkyl sulfides with alkyl grignard reagents using (Z)-3,3-dimethyl-1,2- bis(diphenylphosphino)but-1-ene as ligand
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A combination of nickel(II) acetylacetonate and (Z)-3,3-dimethyl-1,2- bis(diphenylphosphino)but-1-ene catalyzes cross-coupling reactions of alkyl aryl sulfides and alkenyl alkyl sulfides with alkyl Grignard reagents. Not only primary but also secondary alkyl Grignard reagents can be employed. Georg Thieme Verlag Stuttgart.
- Kanemura, Shigenari,Kondoh, Azusa,Yorimitsu, Hideki,Oshima, Koichiro
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scheme or table
p. 2659 - 2664
(2009/04/05)
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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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(2008/06/13)
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- Production of dialkylbenzenes
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The invention relates to a process for producing a desired dialkylbenzene isomer having a formula R2C6H4, where R is an alkyl substituent, by contacting a polyalkylbenzene compound of formula RnC6Hsu
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(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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- 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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(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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- 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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- Syntheses of novel chiral 2,5-dialkyl-7-azabicyclo[2.2.1]heptanes and 2,5-dialkyl-7-thiobicyclo[2.2.1]heptanes
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New C2-symmetric chiral amines with a rigid bicyclic framework have been synthesized via hydrogenation of monoazides catalyzed by 5% Pd/C in methanol. Enantiomerically pure 2,5-dialkyl-7-thiobicyclo[2.2.1]heptanes were made from readily available materials.
- Xiao, Dengming,Zhang, Zhaoguo,Jiang, Qiongzhong,Zhang, Xumu
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p. 5331 - 5334
(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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- Alkylation of benzene, toluene and xylene isomers with C2, C3 and C4 aliphatic alcohols on TiO2 - SiO2 - Al2O3 and MoO3 - SiO2 - Al2O3 catalysts
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Two typical ternary oxides, TiO2-SiO2-Al2O3 (Tisial) and MoO3-SiO2-Al2O3 (Mosial) of optimum acidic properties have been utilized recently as catalysts for certain organic transformations.The present paper describes the results of a systematic study on th
- Sabu, K. R.,Rao, K. V. C.,Nair, C. G. R.
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p. 1053 - 1061
(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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- 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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- Formylation and Acylation Reactions Catalysed by Trifluoromethanesulphonic Acid
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Regioselective formylation of toluene, m- and p-xylene, and mesitylene has been achieved by carbonylation in trifluoromethanesulphonic acid at CO pressures of 90-125 atm.In the case of cumene, the formylation reaction is in competition with disproportionation to form di- and tri-isopropylbenzenes, leading to a complex product mixture.Slow addition of cyclohexene or cyclopentene to a mixture of benzene and CF3SO3H under a high CO pressure affords 4-cyclohexylbenzaldehyde and 4-cyclopentylbenzaldehyde in 34percent and 33percent yieds, respectively, while 2-methylbut-1-ene gives 2,2,3-trimethylindanone (39percent) under similar conditions.When cyclohexene is mixed with the acid under carbon monoxide (120 atm) before addition of benzene the major products are cyclohexyl phenyl ketone and cyclohexenyl cyclohexyl ketones.
- Booth, Brian L.,El-Fekky, Teymour A.,Noori, Ghazi F. M.
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p. 181 - 186
(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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