- Temperature-controlled phase-transfer hydrothermal synthesis of MWW zeolites and their alkylation performances
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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
- Xing, Enhui,Shi, Yanchun,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
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p. 29707 - 29717
(2018/06/04)
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- Method for simultaneously synthesizing methyl-ethylbenzene and diethylbenzene by virtue of one-step method
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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.
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Paragraph 0051-0065
(2016/12/22)
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- Synthesis, characterization and application of MCM-22 zeolites via a conventional HMI route and temperature-controlled phase transfer hydrothermal synthesis
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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.
- Xing, Enhui,Shi, Yanchun,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
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p. 8514 - 8522
(2015/03/05)
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- Size-controlled synthesis of MCM-49 zeolites and their application in liquid-phase alkylation of benzene with ethylene
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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
- Shi, Yanchun,Xing, Enhui,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
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p. 13420 - 13429
(2015/02/19)
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- Enhancing activity without loss of selectivity - Liquid-phase alkylation of benzene with ethylene over MCM-49 zeolites by TEAOH post-synthesis
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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
- Shi, Yanchun,Xing, Enhui,Xie, Wenhua,Zhang, Fengmei,Mu, Xuhong,Shu, Xingtian
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p. 135 - 144
(2015/09/28)
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- Crystal dimension of ZSM-5 influences on para selective disproportionation of ethylbenzene
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Crystal size and crystal dimensions are vital role in shape selective feature. Para selective disproportionation of EthylBenzene (Dip-EB) was investigated over ZSM-5 synthesized in acidic medium. The catalysts were prepared by hydrothermal process with va
- Hariharan, Srinivasan,Palanichamy, Muthaiahpillai
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p. 2493 - 2500
(2014/03/21)
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- Phosphate modified ZSM-5 for the shape-selective synthesis of para-diethylbenzene: Role of crystal size and acidity
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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.
- Hodala, Janardhan L.,Halgeri, Anand B.,Shanbhag, Ganapati V.
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- Highly selective synthesis of para-diethylbenzene by alkylation of ethylbenzene with diethyl carbonate over boron oxide modified HZSM-5
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A series of B2O3/HZSM-5 catalysts were prepared by impregnation of HZSM-5 zeolites with triethyl borate, trimethyl borate and boric acid. The selective synthesis of para-diethylbenzene by alkylation of ethylbenzene with diethyl carbonate was carried out over the B2O3/HZSM-5 catalysts. The physicochemical properties of the catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy with pyridine adsorption and NH3 temperature programmed desorption. The characterization results indicated that the 15% B2O3/HZSM-5 catalyst prepared by using triethyl borate as the precursor exhibited an outstanding shape-selectivity along with a high catalytic activity in alkylation of ethylbenzene with diethyl carbonate. This might be ascribed to the large molecular size of triethyl borate, which would lead to the formation of B2O3 on the external surface of HZSM-5 zeolite and preserve the acid sites in the micropores of HZSM-5 zeolite. By contrast, the B2O3/HZSM-5 catalysts prepared by using trimethyl borate or boric acid led to the severe reduction in catalytic activity, which was attributed to the decrease in the amount of the total acid sites caused by the blockage of the partial pores of HZSM-5 zeolite.
- Xue, Bing,Zhang, Gen,Liu, Na,Xu, Jie,Shen, Qingming,Li, Yongxin
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p. 384 - 391
(2015/01/08)
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- Vapour phase ethylation of benzene over ZSM-5 synthesized in fluoride medium
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ZSM-5 zeolite (Si/Al ratio 50, 75 and 100) was hydrothermally synthesized in fluoride medium. Their crystal size and crystallinity were high. SEM images of synthesized material showed large elongated prismatic crystals. Their catalytic activity was examin
- Hariharan,Palanichamy,Murugesan
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p. 2679 - 2682
(2013/04/24)
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- Platinum(II)-catalyzed ethylene hydrophenylation: Switching selectivity between alkyl- and vinylbenzene production
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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.
- McKeown, Bradley A.,Gonzalez, H. Emanuel,Friedfeld, Max R.,Brosnahan, Anna M.,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
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p. 2857 - 2865
(2013/06/26)
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- PtII-catalyzed ethylene hydrophenylation: Influence of dipyridyl chelate ring size on catalyst activity and longevity
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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.
- McKeown, Bradley A.,Gonzalez, Hector Emanuel,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
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p. 1165 - 1171
(2013/07/26)
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- Control of olefin hydroarylation catalysis via a sterically and electronically flexible platinum(II) catalyst scaffold
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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.
- McKeown, Bradley A.,Gonzalez, Hector Emanuel,Michaelos, Thoe,Gunnoe, T. Brent,Cundari, Thomas R.,Crabtree, Robert H.,Sabat, Michal
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p. 3903 - 3913
(2013/08/23)
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- Effects of crystallinity of ZSM-5 zeolite on para-selective tert-butylation of ethylbenzene
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Highly crystalline ZSM-5 zeolites are important for para-selective alkylation of alkyl aromatics, because they carry few external acid sites for isomerization of p-dialkyl products. Such zeolites (Si/Al = 25, 50, and 75) were synthesized in a fluoride medium between pH 4 and 6. Their crystallinities, crystal sizes, and surface areas were higher than those of a commercial ZSM-5 zeolite. Their para selectivities in alkylation were tested for vapor-phase tert-butylation of ethylbenzene between 200 and 400 °C. As expected, all the catalysts showed more than 90% para selectivity. At 300 °C, ethylbenzene conversion decreased in the order ZSM-5(25, commercial) > ZSM-5(25) > ZSM-5(50) > ZSM-5(75). The catalysts had weak, medium, and strong acid sites, but all the acid sites of ZSM-5(75) were weaker than those of ZSM-5(25) and ZSM-5(50). The high activity of commercial ZSM-5 was caused by its strong acid sites being stronger than those of the synthesized zeolites. Although the activity of the commercial catalyst was higher than those of the present catalysts, the selectivity for 4-t-butylethylbenzene (4-t-BEB) was low. The optimum feed ratio (ethylbenzene:t-butyl alcohol) was 2:1 and the feed rate was 1.65 h-1 for high ethylbenzene conversion and 4-t-BEB selectivity. Time-on-stream studies showed slow catalyst deactivation. Highly crystalline ZSM-5 zeolites are therefore better than a commercial zeolite for para-selective alkylation of alkyl aromatics. They do not require much post-modification for high para selectivity. A fluoride medium is therefore better than an alkaline medium for obtaining highly crystalline para-selective ZSM-5 zeolites.
- Pushparaj, Hemalatha,Mani, Ganesh,Muthiahpillai, Palanichamy,Velayutham, Murugesan,Park, Yong-Ki,Choi, Won Choon,Jang, Hyun Tae
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p. 294 - 304
(2013/04/10)
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- Mechanistic studies of ethylene hydrophenylation catalyzed by bipyridyl Pt(II) complexes
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Cationic platinum(II) complexes [(tbpy)Pt(Ph)(L)]+ [tbpy =4,4′-di-tert-butyl-2,2′-bipyridyl; L = THF, NC5F5, or NCMe] catalyze the hydrophenylation of ethylene to generate ethylbenzene and isomers of
- McKeown, Bradley A.,Gonzalez, Hector Emanuel,Friedfeld, Max R.,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
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experimental part
p. 19131 - 19152
(2012/01/12)
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- Interconversion equilibrium of para-meta isomerization of alkylbenzenes
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The equilibrium of the reaction of para-meta isomerization of alkylbenzenes in the liquid phase was studied. The thermodynamic characteristics of the reaction were determined and interpreted. It was shown that the enthalpic term of the interaction between substituents in the case of their meta arrangement in the molecule depends on the effective size of the substituents. An approach to the prediction of the equilibrium constants of para-meta isomerization is proposed.
- Nesterov,Nesterova,Roshchupkina
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experimental part
p. 444 - 453
(2010/03/31)
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- Zeolite SSZ-53: An extra-large-pore zeolite with interesting catalytic properties
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(Figure Presented) Wide pores for wide applications: The catalytic properties of SSZ-53, an extra-large-pore high-silica zeolite, were explored by using ethylbenzene disproportionation and the isomerization and hydrocracking of n-decane as test reactions. High activity together with a very open channel system render this zeolite an attractive candidate as catalyst for applications in petroleum refining.
- Tontisirin, Supak,Ernst, Stefan
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p. 7304 - 7306
(2008/09/18)
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- Ethylation of ethylbenzene over AFI type molecular sieves
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Magnesium, manganese and zinc incorporated aluminophosphate molecular sieves, MgMnAPO-5 and MnZnAPO-5, have been prepared by hydrothermal methods. The samples have been characterised by the techniques of XRD, FT-IR, 31P and 27Al MAS-NMR spectroscopy, BET-surface area, n-butylamine-TPD and ICP-MS. The cataiytic performance of these materials has been examined for ethylation of ethylbenzene with ethanoi in the vapour phase. MnZnAPO-5 has been found to be more active than MgMnAPO-5. The products are PDEB (1,4-diethylbenzene), MDEB (1,3-diethylbenzene), ODEB (1,2-diethylbenzene), PAB [(1,2,4 and 1,3,5-triethylbenzene) and (1,2,4,5-tetraethylbenzene)]. Maximum conversion (20.1%) has been noted at 350°C over MnZnAPO-5.
- Raj, K. Joseph Antony,Vijayaraghavan
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p. 254 - 257
(2007/10/03)
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- Catalytic ring-attachment isomerization and dealkylation of diethylbenzenes over halide clusters of group 5 and group 6 transition metals
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A molybdenum halide cluster, (H3O)2[(Mo 6Cl8)Cl6]·6H2O, possessing an octahedral metal framework was used as a catalyst in a gas flow reactor under 1 atm of hydrogen. On reaction of p-diethylbenzene, dehydrogenation to ethylstyrene proceeded selectively at 300°C. At 400°C, mutual interconversion of o-, m-, and p-diethylbenzenes proceeded selectively. The ethyl group migrated by an intramolecular 1,2-shift mechanism without yielding disproportionation products. Niobium and tungsten chloride clusters with the same metal framework were also active catalysts for the isomerization of p-diethylbenzene. All the reactions resulted in appreciable yields of dealkylation products. The catalytic activity for isomerization can be ascribed to acid sites on the cluster surface, and the catalytic activity for dealkylation, to the metallic nature of the framework metal.
- Kamiguchi, Satoshi,Kondo, Kunihiko,Kodomari, Mitsuo,Chihara, Teiji
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- Addition of arenes to ethylene and propene catalyzed by ruthenium
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TpRuII(CO)(Me)(NCMe) (Tp = hydridotris(pyrazolyl)borate) serves as a catalyst precursor for the conversion of benzene and ethylene or propene to alkylaromatic products. The reaction proceeds via the formation of the active catalyst TpRu(CO)(Ph)(NCMe) and is mildly selective for linear propylbenzene over isopropylbenzene. Copyright
- Lail, Marty,Arrowood, Benjamin N.,Gunnoe, T. Brent
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p. 7506 - 7507
(2007/10/03)
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- Correlation between the catalytic activity of pentasils in alkylation of ethylbenzene by aqueous solutions of ethanol and ammonia TPD spectra
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The method of regional analysis of reaction rates was used to establish the correlation between the acidic properties of modified pentasil catalysts and their catalytic activity in the reaction of alkylation of ethylbenzene by ethanol and to determine the acidity range with the highest catalytic activity. The p- and m-isomers were found to be formed on sites having different acidities.
- Yushchenko,Romanovskii
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p. 557 - 562
(2007/10/03)
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- The influence of the external acidity of H-ZSM-5 on its shape selective properties in the disproportionation of ethylbenzene
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The shape selectivity of H-ZSM-5 in the disproportionation of ethylbenzene was investigated, using a set of samples with the same Si/Al ratio, but different particle sizes in the range from 0.1 to 80 μm. The number of external acid sites of each sample was measured gravimetrically by the adsorption of 2,6-dimethylpyridine. The data were correlated with the results of catalytic experiments. Conversion and product distribution are strongly dependent on the external acidity which in turn correlates well with the particle size. An estimate for the diffusion coefficient could be obtained by fitting the effectiveness factor for the different particle sizes.
- Melson, Sabine,Schueth, Ferdi
-
-
- 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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- Shape Selectivity of ZSM-5 Type Zeolite for Alkylation of Ethylbenzene with Ethanol
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The alkylation of ethylbenzene with ethanol on ZSM-5 zeolites was studied at 673 K.The primary product in this alkylation on HZSM-5 catalyst was only p-diethylbenzene because of the transition-state selectivity.Therefore, the isomerization of p-diethylbenzene has to be restrained for the selective formation of p-diethylbenzene.The modified HZSM-5 catalysts with oxide of magnesium, phosphorus or boron showed much higher para-selectivity than the parent HZSM-5.The modification reduced not only the effective pore dimension of HZSM-5 but also the amount of strong acid sites.We claim that the absence of strong acid sites is necessary rather than the narrowness of pores for the suppression of the isomerization of p-diethylbenzene produced as a primary product.
- Kim, Jong-Ho,Namba, Seitaro,Yashima, Tatsuaki
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p. 1051 - 1056
(2007/10/02)
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- CATALYTIC PROPERTIES OF DECATIONATED HTsVM AND H-MORDENITE ZEOLITES.
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A comparison was made of the catalytic properties of decationated HTsVM zeolites (Soviet zeolites of the pentasil family) and of H-mordenite (HM) in conversions of m-xylene and ethylbenzene under elevated hydrogen pressures, under conditions tending to improve the stability of operation of zeolite catalysts. It is found that in conversions of m-xylene and ethylbenzene on decationated mordenite under hydrogen pressure (at 400 degree , total pressure 1. 5 MPa, mass feed rate 15-60 h** minus **1) the yields of products of disproportionation of xylenes and ethylbenzene are equal. In conversions of m-xylene and ethylbenzene on a decationated zeolite of the pentasil family, HTsVM (molar ration SiO//2:Al//2O//3 equals 40:1) under the conditions studied the yields of products of disproportionation of xylenes and ethylbenzene are different: lower than on H-mordenite in the case of xylenes, and higher than on H-mordenite in the case of ethylbenzene.
- Bursian,Martynov,Nikitina,Zhemchugova
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p. 2498 - 2502
(2007/10/02)
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- Alkylation of Arenes with Ethylene over H-ZSM-5 and Modernite-H Catalysis
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Attempts were made to alkylate acetophenone, benzene, benzonitrile, bromobenzene, chlorobenzene, ethylbenzene, fluorobenzene, iodobenzene, methoxybenzene, nitrobenzene, toluene and α,α,α-trifluorotoluene with ethylene over H-ZSM-5 and mordenite-H catalysts at 400 and 250 deg C, respectively.Over H-ZSM-5 benzene, bromobenzene, chlorobenzene, ethylbenzene and toluene gave monoethylarenes as the major product (95-100percent) with the para product as the dominant isomer (87-95percent).Over mordenite-H benzene, bromobenzene, chlorobenzene and toluene reacted.The monoethylarenes were again the major product (85-95percent) but the isomer distributions were close to the thermodynamically controlled ones due to isomerization of the initially formed products.Over H-ZSM-5 the results indicated the reaction to be of a Friedel-Crafts type.It was proposed that the product composition was determined by the chemical reaction, not by the rate of diffusion of the products.
- Akervold, Idar,Bakke, Jan M.,Steinsvik, Eirik
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p. 437 - 444
(2007/10/02)
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- Alkylation Reactions over Ion-exchanged Molecular Sieve Zeolite Catlysts. Part 3. Alkylation of Toluene and Benzene with Ethanol: Consideration of the Effects of Initial Coke Formation on para Selectivity
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The ethylation of toluene and benzene with ethanol at 423 K over a wide range of exchanged NaNH4Y catalysts and also over a NH4Y-91.5 sample calcined at 11 different temperatures between 523 and 875 K has been studied.Alkylation with ethanol was found not
- Coughlan, Brendan,Carroll, William M.,Nunan, John
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p. 311 - 326
(2007/10/02)
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- Studies in Trifluoromethanesulfonic Acid. 3. Kinetics and Mechanism of Transalkylation Reactions
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Rates of disproportionation of ethylbenzene and m-diethylbenzene have been measured in the solvent trifluoromethanesulfonic acid (triflic acid).Ethylbenzene disproportionates very rapidly, whereas m-diethylbenzene reacts at a conveniently measurable rate.The reactions obey first-order kinetics over a wide range of concentration, and the results are interpreted as involving ethyl transfer to the triflate anion followed by alkylation via the ethyl triflate formed.
- Bakoss, H. J.,Roberts, R. M. G.,Sadri, A. R.
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p. 4053 - 4055
(2007/10/02)
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- 78. Ueber den Anteil sigmatroper 1,5-Wanderung von Kohlenwasserstoffgruppen bei der thermolytischen Skelettisomerisierung 5,5-disubstituierter 1,3-Cyclohexadiene
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The uncatalyzed skeletal isomerization of 5,5-disubstituted 1,3-cyclohexadienes was investigated with the aim to establish the extent to which sigmatropic 1,5-shifts of hydrocarbon groups are participating in these reactions.Gas phase pyrolysis of 5,5-diethyl-1,3-cyclohexadiene (7) at 460 deg C followed by chloranil aromatization yields only 4percent of 1,3-diethylbenzene resulting from 7 through a 1,5-ethyl migration in the primary reaction step 2,3-Dimethylethylbenzene (56percent) and 1,4-diethylbentene (4percent) are obtained as other C10-compounds.This shows that isomerization proceeds mainly through a sequence of electrocyclic and 1,7-shift reactions.Ethylbenzene (24percent) and other aromatic C8- and C9-hydrocarbons are formed to a considerable extent, indicating that C,C-bond cleavage is a major competing process and that the 1,3-diethylbenzene found is the result of a radical recombination reaction and not of a concerted sigmatropic shift of the ethyl group. 5-Methyl-5-phenyl-1,3-cyclohexadiene (12) yields 3-methylbiphenyl (14) and biphenyl upon thermolysis and aromatization.Through 13C-substitution of the methyl group in 12 it is shown that in solution at 300 deg skeletal isomerization proceeds through electrocyclic and 1,7-H-shift reactions exclusively.In the gas phase at 500 deg 4percent of the isomerization product is formed by a 1,5-shift of a substituent, presumably of the methyl group, through a dissociative mechanism.Thermolysis of 5,5-diphenyl-1,3-cyclohexadiene (22) at 560 deg in the gas phase leads to 1,1-diphenyl-1,3,5-hexatriene (23) and 1-vinyl-4-phenyl-1,2 dihydronaphthalene (24) through electrocyclic reaction steps.In addition a small amount of m-terphenyl is obtained at high conversion of 22.This indicates that sigmatropic 1,5-phenyl migration can participate in product formation only at high temperature and in the absence of other irreversible pathways to stable products.
- Schiess, Peter,Dinkel, Rolf
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p. 801 - 812
(2007/10/02)
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