253185-02-3Relevant articles and documents
Temperature-controlled phase-transfer hydrothermal synthesis of MWW zeolites and their alkylation performances
Xing, Enhui,Shi, Yanchun,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
, p. 29707 - 29717 (2018/06/04)
MWW zeolites have been synthesized with hexamethyleneimine/aniline as the structure-directing/ promoting agent. As structure-promoting agent, aniline contributes to the crystallization of MWW zeolites without being trapped within zeolites. Meanwhile the t
Method for simultaneously synthesizing methyl-ethylbenzene and diethylbenzene by virtue of one-step method
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Paragraph 0051-0065, (2016/12/22)
The invention relates to a method for simultaneously synthesizing methyl-ethylbenzene and diethylbenzene by virtue of a one-step method. Ethylene, benzene and methylbenzene are taken as raw materials to perform an alkylation reaction so as to synthesize methyl-ethylbenzene and diethylbenzene in one step. The method comprises a pretreatment stage, a reaction stage and an aftertreatment stage. In the method, one reaction system is adopted, and alkylation reaction and aftertreatment are sequentially performed so as to separate components, so that target products are obtained, and thus one-step simultaneous synthesis of methyl-ethylbenzene and diethylbenzene is realized; the problem that two independent devices are respectively used for production in a traditional production process is avoided, and the whole reaction process is convenient and rapid; the yields of different components can be effectively adjusted by adjusting different proportions of raw materials, and unreacted benzene and methylbenzene and the ethylbenzene generated in a reaction process are separated and recycled to serve as raw materials once again, so that the production cost is greatly saved, and meanwhile, the method can adapt to variations of the market to the greatest extent.
Size-controlled synthesis of MCM-49 zeolites and their application in liquid-phase alkylation of benzene with ethylene
Shi, Yanchun,Xing, Enhui,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
, p. 13420 - 13429 (2015/02/19)
Size-controlled synthesis of MCM-49 zeolites was achieved via topology reconstruction from NaY zeolites with different sizes. SEM images showed that the sizes of the reconstructed H-MCM-49 zeolites were controlled by those of the parent NaY zeolites. Smal
Synthesis, characterization and application of MCM-22 zeolites via a conventional HMI route and temperature-controlled phase transfer hydrothermal synthesis
Xing, Enhui,Shi, Yanchun,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
, p. 8514 - 8522 (2015/03/05)
With less environmental and economical impact, temperature-controlled phase transfer hydrothermal synthesis of MWW zeolites was realized with hexamethyleneimine as a structure-directing agent and aniline as a structure-promoting agent. MCM-22 zeolite, synthesized via temperature-controlled phase transfer hydrothermal synthesis, is nearly identical concerning chemical composition and structure, and possesses nearly identical properties with respect to porosity, Si/Al ratio, thermal behavior and catalytic activity at 200°C, compared with that made from conventional synthesis with hexamethyleneimine as the only template.
Enhancing activity without loss of selectivity - Liquid-phase alkylation of benzene with ethylene over MCM-49 zeolites by TEAOH post-synthesis
Shi, Yanchun,Xing, Enhui,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
, p. 135 - 144 (2015/09/28)
As-synthesized and calcined MCM-49 zeolites were post-synthesized by tetraethylammonium hydroxide to tailor their morphology, texture properties, acid sites and catalytic performances. With post-synthesis by tetraethylammonium hydroxide, both as-synthesiz
Phosphate modified ZSM-5 for the shape-selective synthesis of para-diethylbenzene: Role of crystal size and acidity
Hodala, Janardhan L.,Halgeri, Anand B.,Shanbhag, Ganapati V.
, p. 8 - 16 (2014/08/18)
Pore engineered ZSM-5 zeolite in extrudate form was prepared and used as shape-selective catalyst for vapor phase ethylation of ethylbenzene to selectively form para-diethylbenzene. The physico-chemical properties of the catalyst were established by XRD, N2 sorption, FTIR, FESEM, NH 3-TPD and 31P MAS NMR. Alkylation of ethylbenzene with ethanol was carried out in a continuous, down-flow, tubular reactor, at atmospheric pressure and H2 as a carrier gas in vapor phase. Effect of silica to alumina ratio (SAR), crystal size, acidity of phosphate modified ZSM-5, stepwise phosphate modification and reaction conditions were studied in detail. ZSM-5 with SAR 187 was found to contain optimum acidity for phosphate modification to achieve good conversion and high selectivity for p-diethylbenzene. Under optimized reaction conditions, viz. temperature = 380 °C, ethylbenzene:ethanol mole ratio = 4:1, WHSV = 3 h-1, H 2/reactants = 2, 5PZSM-5 W catalyst gave 22.8% of ethylbenzene conversion with ～98% selectivity for para-diethylbenzene.
Synthesis and optical reactivity of 6,13-α-diketoprecursors of 2,3,9,10-tetraalkylpentacenes in solution, films and crystals
Katsuta, Shuhei,Saeki, Hiroyuki,Tanaka, Katsuki,Murai, Yuki,Kuzuhara, Daiki,Misaki, Masahiro,Aratani, Naoki,Masuo, Sadahiro,Ueda, Yasukiyo,Yamada, Hiroko
, p. 986 - 993 (2014/02/14)
Tetraalkylpentacenes having alkyl chains at 2,3,9,10-positions (Et-PEN, Pr-PEN and Hex-PEN) were prepared from their precursors Et-PDK, Pr-PDK and Hex-PDK, respectively. Photoreactions proceeded both in solutions, thin-films, and crystals, thus the properties of Et-PDK in films can be studied despite the instability of the pentacenes in solution. Et-PEN showed significantly different aggregation-nature compared with the parent pentacene. The hole mobilities of Et-PEN and Pr-PEN in films were 3.4 × 10-6 and 8.1 × 10-7 cm2 V-1 s-1, respectively, determined by space-charge-limited current measurement, comparable with the order 10-6 cm2 V-1 s-1 of the electron mobility of Alq3.
Platinum(II)-catalyzed ethylene hydrophenylation: Switching selectivity between alkyl- and vinylbenzene production
McKeown, Bradley A.,Gonzalez, H. Emanuel,Friedfeld, Max R.,Brosnahan, Anna M.,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
, p. 2857 - 2865 (2013/06/26)
The series of PtII complexes [(xbpy)Pt(Ph)(THF)] [BAr′4] (xbpy =4,4′-X-2,2′-bipyridyl, X = OMe, tBu, H, Br, CO2Et, NO2; Ar′ = 3,5-bis(trifluoromethyl)phenyl) are catalyst precursors for ethylene hydrophenylation. The bipyridyl substituent provides a tunable switch for catalyst selectivity that also has significant influence on catalyst activity and longevity. Less electron donating 4,4′-substituents increase the propensity toward styrene formation over ethylbenzene.
PtII-catalyzed ethylene hydrophenylation: Influence of dipyridyl chelate ring size on catalyst activity and longevity
McKeown, Bradley A.,Gonzalez, Hector Emanuel,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
, p. 1165 - 1171 (2013/07/26)
Expansion of the dipyridyl ligand from a five- to six-membered chelate for PtII-catalyzed ethylene hydrophenylation provides an enhancement of catalyst activity and longevity. Mechanistic studies of [(dpm)Pt(Ph)(THF)] [BAr′4] [dpm = 2,2′-dipyridylmethane, and Ar′ = 3,5-(CF3)2C6H3] attribute the improved catalytic performance at elevated temperatures to a favorable change in entropy of activation with an increase in chelate ring size. The Pt II catalyst precursor [(dpm)Pt(Ph)(THF)][BAr′4] is among the most active catalysts for ethylene hydrophenylation by a non-acid-catalyzed mechanism.
Control of olefin hydroarylation catalysis via a sterically and electronically flexible platinum(II) catalyst scaffold
McKeown, Bradley A.,Gonzalez, Hector Emanuel,Michaelos, Thoe,Gunnoe, T. Brent,Cundari, Thomas R.,Crabtree, Robert H.,Sabat, Michal
, p. 3903 - 3913 (2013/08/23)
PtII complexes supported by dipyridyl ligands have been demonstrated to catalyze olefin hydroarylation. Herein, studies on the influence of dipyridyl motif variation are reported. Increasing the chelate ring size of dipyridyl-ligated PtII complexes from five- to six-membered rings by replacing 4,4′-di-tert-butyl-2,2′-bipyridine with 2,2′-dipyridylmethane has been shown to increase catalytic activity and longevity for catalytic ethylene hydrophenylation. For 2,2′-dipyridyl ligands, the presence of methyl groups in the 6/6′-positions of the pyridyl rings reduces the extent of dialkylation to produce diethylbenzenes but also increases the rate of catalyst decomposition. Substituting the methylene spacer between the pyridyl rings of 2,2′-dipyridylmethane with more electron-withdrawing groups also reduces catalytic efficiency. The steric profile of PtII complexes with increased chelate ring size or substituents in the 6/6′-positions of the pyridyl rings provides a marked change in regioselectivity for ethylene hydroarylation using ethylbenzene as well as the linear to branched selectivity for the hydrophenylation of propylene.
