- Isobutane/2-Butene Alkylation on Ultrastable Y Zeolites: Influence of Zeolite Unite Cell Size
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The alkylation reaction of isobutane with trans-2-butene has been carried out on a series of steam-dealuminated Y zeolites with unit cell sizes ranging from 2.450 to 2.426 nm.A fixed-bed reactor connected to an automatized multiloop sampling system allowed us to make differential product analysis from very short (1 min or less) to longer times on stream.A maximum in the initial 2-butene conversion was found on samples with unit cell sizes between 2.435 and 2.450 nm.However, the TMP/DMH ratio, i.e., the alkylation-to-oligomerization ratio, continuously increased withzeolite unit cell size.The concentration of reactants in the pores, the strength distribution of Broensted acid sites, and the extent of hydrogen transfer reactions, which in turn depend on the framework Si/Al ratio of a given zeolite, were seen to affect activity and product distribution of the catalysts.Finally, the influence of these factors on the aging characteristics of the samples was also discussed.
- Corma, A.,Martinez, A.,Martinez, C.
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- Formation of trimethylpentanes from isobutane and 1-butene catalyzed by sulfated metal oxides
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The gas-phase alkylation of 1-butene with isobutane was carried out over superacids of sulfated metal oxides, SO4/Fe2O3, SO4/Al2O3, SO4/TiO2, SO4/SnO2, and SO4/ZrO2, at 0 °C; SO4/SnO2 gave the highest yield of trimethylpentane (TMP). It was proved from relationship between the catalyst acidities and the yields of C8 paraffins that the first intermediate species was a t-butyl cation formed on the superacidic Lewis site by abstraction of H- followed by the alkylation with butenes to form TMP.
- Satoh, Kunihiko,Matsuhashi, Hiromi,Arata, Kazushi
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- Hybrid Catalysts Based on Sulfated Zirconium Dioxide and H-beta Zeolite for Alkylation of Isobutane with Isobutylene
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Physicochemical properties of new hybrid catalysts based on sulfated zirconium oxide supported by zeolite of the Beta structural type were investigated. The acid-base characteristics of the catalysts were determined by the amount of the supported component, the maximum concentration of Br?nsted acid centers (277 Μmol/g) was achieved upon deposition of 1.7 wt.% sulfated zirconium oxide. The texture characteristics of the final catalyst were determined by the starting support. Tests of the catalysts in the reaction of isobutane alkylation with isobutylene demonstrated their advantage in selectivity and stability over the classical bulk sulfated zirconium oxide. The variation of the surface acidity is correlated with the amount of the deposited sulfated zirconium dioxide and has an extremum point at around 4 wt.%. Hybrid catalysts based on H-Beta zeolite with supported sulfated zirconium dioxide are more stable and exhibited a higher selectivity with respect to C8 hydrocarbons and trimethylpentanes, compared with bulk sulfated zirconium dioxide.
- Yuferova,Devyatkov, S. Yu.,Fedorov,Semikin,Sladkovskii,Kuzichkin
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- Identification of acidic species in chloroaluminate ionic liquid catalysts
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Chloroaluminate ionic liquids (ILs), especially composite ionic liquids (CILs) which are ILs modified with copper(I) chloride, are highly active and selective catalysts for the alkylation of 2-butene with isobutane. The Lewis and Bronsted acidic species of these ILs were investigated by NMR spectroscopy. Pyridine is found to be a suitable indicator. Lewis acidity arises mainly from Al2Cl7- having a chemical shift at 102 ppm in the 27Al NMR spectrum, while Bronsted acidity arises from Al2Cl6OH- (chemical shift at 97 ppm). The peak at 94 ppm in the 27Al NMR spectrum is related to Al2Cl5O-. These new insights have improved our understanding of the structure of the active species in chloroaluminate ionic liquid alkylation catalysts.
- Cui, Jia,De With, Jan,Klusener, Peter A. A.,Su, Xiaohong,Meng, Xianghai,Zhang, Rui,Liu, Zhichang,Xu, Chunming,Liu, Haiyan
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- In Situ Formation of Al(Fe)/Cl Metal Chloride Complexes and Evaluation of Their Catalytic Properties in the Reaction of Ethylene Oligomerization
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The reactivity of the Al/Fe alloy with respect to organochlorine compounds for producing in situ catalytic (Fe-, Al/Cl) complexes from the systems Al/Fe/ tert-butyl chloride (TBC) and Al/Fe/TBC in n-hexane was investigated, together with their catalytic p
- Arbuzov,Kudrya,Trenikhin,Drozdov
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- MxOy/SO42--/dealuminated zeolite β (M=Ti, Fe) as novel catalysts for alkylation of isobutane with 1-butene
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A new kind of MxOy/SO42--/H-form dealuminated β (DHβ) catalysts prepared here were applied to alkylation of isobutane with 1-butene. The group of MxCy/SO42-/DHβ (M = Ti, Fe) catalysts has a lower rate of deactivation and higher selectivity of this alkylation than other group of Hβ and DHβ. It is proposed that the strong acid sites corresponding to the active sites for this alkylation can be formed by the interaction among DHβ, MxOy, and SO42-.
- Sun, Mingxing,Sun, Jianwei,Li, Quanzhi
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- Stages of aging and deactivation of zeolite LaX in isobutane/2-butene alkylation
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The formation of carbonaceous deposits and their effect on aging and deactivation of zeolite LaX during isobutane/2-butene alkylation at 348 K were investigated by stopping the reaction at different times on stream. Four stages of the reaction were identified: (1) stable alkylation, (2) deposit transformation, (3) slow deactivation, and (4) rapid deactivation. Deposits consist mostly of bicyclic compounds and branched carbenium ions, which are formed already at the beginning of the reaction and block Bronsted acid sites. During the deposit transformation, migration of smaller entities toward the pore mouth occurs. These cyclic compounds are further alkylated and lead to pore mouth plugging. In the final stage of rapid deactivation, the catalyst stops producing alkylate, and butene oligomerization is the main reaction leading to olefin desorption and massive deposit formation at the outside of the zeolite particles.
- Sievers, Carsten,Zuazo, Iker,Guzman, Alexander,Olindo, Roberta,Syska, Hitrisia,Lercher, Johannes A.
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- Ionic liquid-catalyzed alkylation of isobutane with 2-butene
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A detailed study of the alkylation of isobutane with 2-butene in ionic liquid media has been conducted using 1-alkyl-3-methylimidazolium halides-aluminum chloride encompassing various alkyl groups (butyl-, hexyl-, and octyl-) and halides (Cl, Br, and I) on its cations and anions, respectively. The emphasis has been to delineate the role of both cations and anions in this reaction. The ionic liquids bearing a larger alkyl group on their cation ([C8mim]) displayed relatively higher activity than a smaller one ([C6 or C4mim]) with the same anionic composition, due to the high solubility of reactants in the former. Among the ionic liquids with different halide groups, bromides ([C8mim]Br-AlCl3) showed outstanding activity, because of the higher inherent acidity relative to others. From the 27Al NMR study, a major peak at ~99.5 ppm corresponding to [AlCl3Br]- (~99.5 ppm) was observed. Moreover, the anion showed a strong acidity based on FT-IR characterization; the largest peak related to acidity (1570 cm-1) was detected. Under various composition conditions, catalytic activity and amount of TMPs increased with concentration of anion. This is mainly attributed to a higher amount of strong acid ions [Al2Cl6Br]- which can react with hydrogen atoms at the 2-position of an imidazolium ion to form Bronsted acid. However, the ionic liquid with strong acidity (X=0.58) deactivated rapidly due to a higher sensitivity to moisture, causing decomposition. Under various reaction temperature conditions, optimum catalytic activity was observed at 80°C. The result is also attributed to the effect of anion composition. The strong acidic anion increased with temperature. However, at higher reaction temperatures (120°C), the ionic liquid showed a lower activity and TMP selectivity, since the solubility and Bronsted acid sites were reduced by decomposition of imidazolium ions. The selected ionic liquid sample ([C8mim]Br-AlCl3) was compared with one of the standard commercial catalysts, sulfuric acid. Under optimum experimental conditions, it was observed that both catalysts showed comparable catalytic behavior. However, ionic liquid showed higher activity, and lower TMP selectivity due to a more acidic nature and a lower amount of Bronsted acid sites, respectively.
- Yoo, Kyesang,Namboodiri, Vasudevan V.,Varma, Rajender S.,Smirniotis, Panagiotis G.
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- A Polymer-Supported Organotin Hydride and Its Multipurpose Application in Radical Organic Synthesis
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The multipurpose application of a polystyrene-supported, regenerable organotin hydride for radical organic syntheses is demonstrated using 10 examples taken from dehalogenation of bulky or multifunctional halides, dehydroxylation of secondary alcohols, and deamination of secondary or tertiary amines.
- Gerlach, Martin,Joerdens, Frank,Kuhn, Heiko,Neumann, Wilhelm P.,Peterseim, Markus
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- HYDROTHERMAL PRODUCTION OF ALKANES
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Synthesizing an alkane includes heating a mixture including an alkene and water at or above the water vapor saturation pressure in the presence of a catalyst and one or both of hydrogen and a reductant, thereby hydrogenating the alkene to yield an alkane and water, and separating the alkane from the water to yield the alkane. The reductant includes a first metal and the catalyst includes a second metal.
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Paragraph 0022; 0035-0036
(2021/04/17)
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- High-Quality Gasoline Directly from Syngas by Dual Metal Oxide–Zeolite (OX-ZEO) Catalysis
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Despite significant efforts towards the direct conversion of syngas into liquid fuels, the selectivity remains a challenge, particularly with regard to high-quality gasoline with a high octane number and a low content of aromatic compounds. Herein, we show that zeolites with 1D ten-membered-ring (10-MR) channel structures such as SAPO-11 and ZSM-22 in combination with zinc- and manganese-based metal oxides (ZnaMnbOx) enable the selective synthesis of gasoline-range hydrocarbons C5–C11 directly from syngas. The gasoline selectivity reached 76.7 % among hydrocarbons, with only 2.3 % CH4 at 20.3 % CO conversion. The ratio of isoparaffins to n-paraffins was as high as 15, and the research octane number was estimated to be 92. Furthermore, the content of aromatic compounds in the gasoline was as low as 16 %. The composition and structure of ZnaMnbOx play an important role in determining the overall activity. This process constitutes a potential technology for the one-step synthesis of environmentally friendly gasoline with a high octane number from a variety of carbon resources via syngas.
- Li, Na,Jiao, Feng,Pan, Xiulian,Chen, Yuxiang,Feng, Jingyao,Li, Gen,Bao, Xinhe
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supporting information
p. 7400 - 7404
(2019/05/10)
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- PROCESS OF MAKING OLEFINS OR ALKYLATE BY REACTION OF METHANOL AND/OR DME OR BY REACTION OF METHANOL AND/OR DME AND BUTANE
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Methods of simultaneously converting butanes and methanol to olefins over Ti-containing zeolite catalysts are described. The exothermicity of the alcohols to olefins reaction is matched by endothermicity of dehydrogenation reaction of butane(s) to light olefins resulting in a thermo- neutral process. The Ti-containing zeolites provide excellent selectivity to light olefins as well as exceptionally high hydrothermal stability. The coupled reaction may advantageously be conducted in a staged reactor with methanol/DME conversion zones alternating with zones for butane(s) dehydrogenation. The resulting light olefins can then be reacted with iso-butane to produce high-octane alkylate. The net result is a highly efficient and low cost method for converting methanol and butanes to alkylate.
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Page/Page column 15; 25; 26; 31; 32
(2017/05/10)
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- Effects of catalyst composition on the ionic liquid catalyzed isobutane/2-butene alkylation
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Ionic liquid catalyzed isobutane/2-butene alkylation modified with metal compounds was studied. The effect of catalyst composition on the alkylation selectivity was investigated. 27Al NMR, ESI-MS, and FTIR spectra reveal that the catalytic selectivity of the modified ionic liquid is probably determined by the catalyst composition rather than by the acid strength. The complexation of transition metal with 2-butene can increase the internal isobutane-to-olefin ratio of feed during the alkylation reaction, which results in the better selectivity of the modified ionic liquid. The best ionic liquid catalysts were those containing CuAlCl4 complexes, giving the alkylate with 87.5 wt% trimethylpentanes and a calculated research octane number (RON) of 100.5.
- Liu, Ying,Li, Rui,Sun, Hongjuan,Hu, Ruisheng
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p. 133 - 139
(2015/02/19)
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- Enhancement of dehydrogenation and hydride transfer by La3+ cations in zeolites during acid catalyzed alkane reactions
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La3+ cations exchanged into ultrastable zeolite Y and zeolite X promote catalytic isomerization, cracking, and alkylation of alkanes. La 3+ cations stabilize the zeolite lattices and, more importantly, polarize alkane C-H bonds to enhance the rates of all three reactions. This unique activity leads to stable cracking and isomerization of reactive alkanes, with polarizable C-H bonds with adjacent tertiary or quaternary carbon atoms below 370 K. The presence of La3+ cations also enhances the zeolite catalyzed hydride transfer rate for isobutane alkylation with 2-butene leading to high catalyst stability. Solid state MAS NMR shows that the strongest positive effects are associated with nonhydroxylated La3+ cations accessible to the reacting molecules in supercages of the zeolite. The high activity is the result of a cooperative polarization of C-H bonds of alkanes by La3+ cations and the presence of stable and strong Bronsted acid sites.
- Schuessler, Florian,Schallmoser, Stefan,Shi, Hui,Haller, Gary L.,Ember, Erika,Lercher, Johannes A.
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p. 1743 - 1752
(2014/06/24)
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- Highly efficient trimerization of isobutene over silica supported chloroaluminate ionic liquid using C4 feed
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A series of silica, glass and molecular sieves supported chloroaluminate ionic liquids (ILs) were prepared and their catalytic performance on the trimerization of isobutene based on C4 mixture was investigated. Interestingly, it was found that the carrier played a key role in the reaction route. Among these supported catalysts, silica supported chloroaluminate ionic liquid was highly efficient for the trimerization of isobutene. X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) characterizations suggested that the synergy between Al2Cl7- anion and silica induced the catalytic activity for isobutene oligomerization due to the strong interaction between ILs and silanol group. The reaction conditions including loading amount, temperature, reactant concentration, and space velocity for the isobutene oligomerization were optimized. Ultimately, complete conversion of isobutene and 91.4% selectivity of trimers were obtained over the IL/silica (30 wt.%) catalyst at mild conditions. Moreover, catalyst stability and deactivation were preliminarily studied.
- Liu, Shimin,Shang, Jianpeng,Zhang, Shiguo,Yang, Benqun,Deng, Youquan
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- Ionic liquid enhanced alkylation of iso-butane and 1-butene
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The alkylation of iso-butane with 1-butene was catalyzed by triflic acid (TFOH) coupled with a series of protic ammonium-based ionic liquids (AMILs), and the addition of the AMILs dramatically enhanced the efficiency of TFOH for the alkylation reaction. Up to 85.1% trimethylpentanes (TMP) selectivity and 98 research octane number (RON) were achieved with the optimized TFOH/AMIL catalyst (75 vol.% triflic acid and 25 vol.% triethylammonium hydrogen sulfate), which were much better than that with the commercial H2SO4 catalyst (65% TMP selectivity, 97 RON) and pure triflic acid. The addition of AMILs increased the I/O ratio dissolved in the catalyst system and adjusted the acidity of the TFOH/AMILs catalyst system, which were highly beneficial to the alkylation reaction and resulted in high TMP selectivity and high RON.
- Cui, Peng,Zhao, Guoying,Ren, Hailing,Huang, Jun,Zhang, Suojiang
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- A new disilene with π-accepting groups from the reaction of disilyne RSi≡SiR (R = SiiPr[CH(SiMe3)2]) with isocyanides
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The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4- diisopropyltetrasila-2-yne (1) with tert-butylisocyanide or tert-octylisocyanide produced the corresponding disilyne-isocyanide adducts [RSiSiR(CNR′) 2] (R = SiiPr[CH(SiMe3)2] 2, R′ = tBu (2a) or CMe2CH 2tBu (2b)), which are stable below -30 °C and were characterized by spectroscopic data and, in the case of 2a, X-ray crystallography. Upon warming to room temperature, 2 underwent thermal decomposition to produce 1,2-dicyanodisilene R(NC)Si=Si(CN)R (3) and 1,2-dicyanodisilane R(NC)HSiSiH(CN)R (4) via C-N bond cleavage and elimination of an alkane and an alkene. The 1,2-dicyanodisilene derivative 3 was characterized by X-ray crystallography.
- Takeuchi, Katsuhiko,Ichinohe, Masaaki,Sekiguchi, Akira
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supporting information; experimental part
p. 2954 - 2957
(2012/04/10)
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- Effective production of octane from biomass derivatives under mild conditions
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Cool cats dont feel pressure: Furfural is catalytically converted into octane in high yields at relatively low pressures and temperatures. In a three-step process, two bifunctional catalysts, Pt/Co2AlO4 and Pt/NbOPO4, play crucial roles in achieving C8-ols from 4-(2-furyl)-3-buten-2-one and transforming the C8-ols into octane, respectively.
- Xu, Wenjie,Xia, Qineng,Zhang, Yu,Guo, Yong,Wang, Yanqin,Lu, Guanzhong
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experimental part
p. 1758 - 1761
(2012/03/27)
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- DIMERIZATION PROCESS
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A process for the dimerization of isoolefins is disclosed. The process may include: contacting an isoolefin with sulfurous acid in a reaction zone at conditions of temperature and pressure sufficient to dimerize at least a portion of the isoolefin
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Page/Page column 4-5
(2011/04/18)
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- Effective n-octane isomerization under exceptionally mild conditions using a novel class of superacidic ionic liquids
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Superacidic chloroaluminate ionic liquids of the general formula [cation]Cl/AlCl3[X(AlCl3) > 0.5] + H2SO 4 effectively isomerize n-octane to form branched liquid hydrocarbon isomers. Due to the highly acidic character of the ionic liquid the reaction proceeds under extremely mild conditions in a liquid-liquid biphasic reaction mode leading to a minimum of undesired cracking side-reactions.
- Meyer, Carolin,Wasserscheid, Peter
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scheme or table
p. 7625 - 7627
(2010/12/19)
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- Alkylation of isobutane with 2-butene using ionic liquids as catalyst
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Alkylation of isobutane with 2-butene was performed in a batch reactor using the ionic liquid 1-n-octyl-3-methylimidazolium bromide aluminium chloride ([OMIM]Br-AlCl3) pure, and in a mixture with compounds containing SO3H-groups. The acidity of the ionic liquid (IL) was modified by the addition of acid cation exchange resins (dry or with a small amount of water), or by the addition of a second IL ([(HO3SBu)MIM]HSO4). A high content of the desired trimethylpentanes (up to 64%) and thus a high research octane number (RON up to 96) of the alkylate was obtained. The reusability of the IL systems was studied and compared with a catalyst commercially used at present (H2SO4).
- Bui, Thi Le Thuy,Korth, Wolfgang,Aschauer, Stephan,Jess, Andreas
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scheme or table
p. 1961 - 1967
(2010/06/15)
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- Zeolites as the modern catalysts for the high octane gasoline component production
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Processes of isobutane with butenes alkylation with the purpose of obtaining the high octane gasoline'component (alkylate), being environmentally detrimental due to use of concentrated H2SO4 or HF acids as catalysts, are nevertheless of great industrial importance supplying the world market with approximately 80 mln tons of alkylate yearly. The perspective of zeolite catalysts as the substitutes of the above concentrated acids in the modern alkylation process has been considered. The most effective today's solid alkylation catalyst of the narrow acid spectrum has been found. Such acidity spectrum is considered to be responsible for the essential prolongation of the effective catalyst lifetime.
- Patrylak,Patrylak,Ionin,Voloshyna,Skubiszewska-Zieba,Repetskyi
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p. 101 - 106
(2008/09/19)
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- Paraffin alkylation
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A liquid acid process is disclosed in which a hydrocarbon component containing an olefin, an olefin precursor or mixture and an isoalkane and a liquid acid catalyst is fed to a downflow reaction zone containing a disperser, under conditions to induce pulse flow at or near the outlet to react the isoalkane and olefin to produce a reaction product and feeding the reaction product to a vaporization zone containing a disperser under conditions to induce pulse flow at or near the outlet of the vaporization zone. A pressure drop across the disperser in the vaporization zone causes partial vaporization of the hydrocarbon which quench es the heat reaction and cooling the unvaporized portion of said reaction product, which is recovered and allowed to separate into an acid phase and hydrocarbon phase containing the alkylate. The acid catalyst and hydrocarbons may be fractally fed to the reaction zone.
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Page/Page column 7
(2008/06/13)
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- Alkylation process with recontacting in settler
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A system and/or process for decreasing the level of at least one organic fluoride present in a hydrocarbon phase contained in an alkylation settler by contacting the hydrocarbon phase with an HF containing stream, containing greater than about 80 wt. % and less than about 94 wt. % HF, in the intermediate portion of the settler which contains at least one tray system, with each tray system comprising a perforated tray defining a plurality of perforations and a layer of packing below the perforated tray, are disclosed.
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Page/Page column 3-5
(2008/06/13)
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- SYSTEM AND METHOD FOR PURIFYING HEPTANE
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Removing impurities from a heptane stream by contacting the heptane stream with an acidic catalyst, wherein the contacting reduces a concentration of one or more close boiling impurities, one or more olefins, or both. The impurities are isomerized via contact with the acidic catalyst into species that possess lower octane levels or that do not possess boiling points as near to the boiling point of n-heptane, which promotes separation of the impurities via distillation. Close boiling impurities may include such compounds as cis-1,2-dimethylcyclopentane and methylcyclohexane or may be compounds having boiling points at a standard pressure of 760 Torr in the range of about 96.5 to about 100.5 degrees Celsius including such compounds as cis-1,2-dimethylcyclopentane and methylcyclohexane. The concentration of cis-1,2-dimethylcyclopentane and methylcyclohexane may be reduced by at least about 25 and 10 percent by weight, respectively. The concentration of olefins, as measured by the Bromine Index, may be reduced by at least about 25 percent by weight.
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Page/Page column 26-31
(2008/06/13)
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- Ionic liquid and solid HF equivalent amine-poly(hydrogen fluoride) complexes effecting efficient environmentally friendly isobutane-isobutylene alkylation
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Isoparaffin-olefin alkylation was investigated using liquid as well as solid onium poly(hydrogen fluoride) catalysts. These new immobilized anhydrous HF catalysts contain varied amines and nitrogen-containing polymers as complexing agents. The liquid poly(hydrogen fluoride) complexes of amines are typical ionic liquids, which are convenient media and serve as HF equivalent catalysts with decreased volatility for isoparaffin-olefin alkylation. Polymeric solid amine:poly(hydrogen fluoride) complexes are excellent solid HF equivalents for similar alkylation acid catalysis. Isobutane-isobutylene or 2-butene alkylation gave excellent yields of high octane alkylates (up to RON = 94). Apart from their excellent catalytic performance, the new catalyst systems significantly reduce environmental hazards due to the low volatility of complexed HF. They represent a new, green class of catalyst systems for alkylation reactions, maintaining activity of HF while minimizing its environmental hazards.
- Olah, George A.,Mathew, Thomas,Goeppert, Alain,Toeroek, Bela,Bucsi, Imre,Li, Xing-Ya,Wang, Qi,Marinez, Eric R.,Batamack, Patrice,Aniszfeld, Robert,Surya Prakash
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p. 5964 - 5969
(2007/10/03)
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- COMPOSITE CATALYST FOR THE SELECTIVE OLIGOMERIZATION OF LOWER ALKENES AND THE PRODUCTION OF HIGH OCTANE PRODUCTS
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The present invention relates to a) a catalytic composite comprising a support structure and a catalytic species that is deposited on the support structure, b) a process for the selective oligomerization of lower alkenes and mixtures of alkenes, which process comprises contacting the lower alkenes with the catalytic composite in a catalytic distillation apparatus and under catalytic distillation conditions, and c) a process for producing high octane products, which process comprises hydrogenating one or more catalytic distillation apparatus and under catalytic distillation conditions.
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Page/Page column 48-52
(2008/06/13)
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- Disproportionation of hydrocarbons
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A novel hydrocarbon disproportionation process is provided and includes contacting a hydrocarbon feed comprising at least one paraffin with a disproportionation catalyst comprising a support component, a metal, and a halogen in a disproportionation reaction zone under disproportionation reaction conditions.
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- Alkene oligomerization process
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A process for oligomerising alkenes having from 3 to 6 carbon atoms which comprises contacting a feedstock comprising a) one or several alkenes having x carbon atoms, and, b) optionally, one or several alkenes having y carbon atoms, x and y being different, with a catalyst containing a zeolite of the MFS structure type, under conditions to obtain selectively oligomeric product containing predominant amounts of certain oligomers. The process is carried out at a temperature comprised between 125 and 175° C. when the feedstock contains only alkenes with 3 carbon atoms and between 140 and 240° C., preferably between 140 and 200° C. when the feedstock contains comprises at least one alkene with 4 or more carbon atoms.
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- Catalyst and process for contacting a hydrocarbon and ethylene
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A process of contacting at least one feed hydrocarbon, containing three to about seven carbon atoms per molecule, and ethylene in a hydrocarbon-containing fluid in the presence of a catalyst composition to provide at least one product hydrocarbon isomer containing about four to about nine carbon atoms per molecule is provided. The at least one feed hydrocarbon can be selected from paraffins, isoparaffins, and the like and combinations thereof. The catalyst composition contains a hydrogen halide component, a sulfone component, and a metal halide component.
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- PROCESS FOR THE MANUFACTURE OF A GASOLINE BLENDING COMPONENT
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The present invention relates to a process for the manufacture of paraffinic hydrocarbons, which can be used as gasoline blending components. The obtained gasoline blending component is substantially free of sulphur compounds. The process comprises simultaneous hydrogenation of olefins and degradation of sulphur compounds by hydrogenolysis. In the process a feed-stock containing as impurities sulphur compounds is hydrogenated in two steps in the presence of a noble metal catalyst on aluminium oxide support, and in the first step the major part of olefins are converted and in the secondary step the remaining olefins and sulphur compounds react.
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- Catalyst on the basis of a Zr, Ti or Hf complex and process for hydrogenation of olefins or polymer
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The present invention relates to a catalyst composition which comprises at least: a) a metal compound cation of the formula [(A)(B)ML+] wherein M represents titanium, zirconium, or hafnium, wherein A and B represent ligands with structure I or II in which R1independently represents the same or different hydrocarbyl groups optionally containing heteroatoms, and R3independently represents the same or different hydrocarbyl groups optionally containing heteroatoms, or a halide, and in which R substituents may be shared between A and B to provide a bridge, wherein m is an integer from 0-5, p is an integer from 0-4, and q is an integer from 0-3, wherein L represents hydrogen or hydrocarbyl group optionally containing heteroatoms, with the proviso that if A and B are both ligands with structure I or II, at least one of m, p or q is at least 1, and b) a non-coordinating stable anion. The present invention further relates to a process for the preparation of a catalyst composition and to a process for the catalytic hydrogenation of olefins, oligomers, polymers or copolymers.
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- The kinetics and selectivity of the decomposition of diacyl peroxides under high pressure in hydrocarbon solution
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The decomposition kinetics of bis(3,5,5-trimethylhexanoyl) peroxide (BTMHP), dioctanoyl peroxide and dibenzoyl peroxide have been monitored under high pressure using time-resolved FTIR spectroscopy. Two experimental methods, one discontinuous the other continuous, were used for BTMHP, and their complementary nature allows measurement of the kinetics in an extended range of decomposition half-lives. Using n-heptane as solvent, investigations were carried out at temperatures from 60 up to 160°C, and in the pressure range 1 to 2500 bar. For BTMHP an activation energy of (131.2±6.5) kJ mor-1 was determined at 1500 bar. The value found at the same pressure for dioctanoyl peroxide is identical within experimental error, whilst that of dibenzoyl peroxide is slightly lower. An activation volume of ΔV≠ = (2.9±0.1) cm3 mol-1 was evaluated for the decomposition of BTMHP, and those of the remaining two peroxides found to be similar. The selectivity of the decomposition of BTMHP was considered by means of GC analysis. Using n-heptane and n-pentadecane as solvents, the effect of pressure on product distributions has been gauged from 1 to 2000 bar at 80°C. For the two main decomposition products, 2,4,4-trimethyl pentane (TMP) and 2,2,4,7,9,9-hexamethyl decane (HMD), pressure was found to enhance the formation of in-cage alkane dimer (HMD) relative to out-of-cage alkane (TMD). ? by R. Oldenbourg Verlag, 1996.
- Buback, Michael,Hinton, Cassandra
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- Magnetic field effects on recombination fluorescence in liquid iso-octane
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The 123.6 nm photoionization of deuterated isooctane at -10 deg C in the presence of hexafluorobenzene has been studied by examining the effect of a magnetic field to alter the quantum yield of recombination fluorescence.This fiuorescence results from geminate recombination of hexafiuorobenzene anions with isooctane positive ions.The use of a deuterated as contrasted to a protonated alkane makes the intensity of the recombination fluorescence much more sensitive to the magnetic field and permits observation of two maxima in the fiuorescence yield at field strengths of 0 and 411 G and a possible third maximum at 822 G.The theory of the hyperfine induced spin evolution predicts these resonances at selected multiples of the C6F6- hyperfine constant of 137 G.Utilizing the diffusion theory of geminate recombination in a Coulomb field, the experimental magnetic field spectrum is found to be well predicted over most of the range of magnetic field strengths studied (up to 2.5 kG) by a simple, one parameter, exponential radial probability density of initial scavenged geminate pair separation distances.
- Saik, Vladimir O.,Ostafin, Agnes E.,Lipsky, Sanford
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p. 7347 - 7358
(2007/10/03)
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- Synthesis, thermochemistry, and reactions of vicinal bis(azoalkanes). The chemistry of α- and β-azo radicals
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Two vicinal bis(azo)alkanes, 8P and 8B, were prepared from acetone phenylhydrazone (APH) and acetone tert-butylhydrazone (ATBH), respectively. Thermolysis of 8P above 130°C in the presence of thiophenol affords APH in quantitative yield, showing that the central C-C bond of 8P cleaves in preference to the usual C-N homolysis of azoalkanes. The resulting radicals 9P recombine to the C-N dimer 16P about 40 times faster than to the more stable C-C dimer 8P. From the combustion heat of 8P, we deduce that its strain enthalpy Hs is 5.5 kcal/mol, while the resonance stabilization energy (RSE) of 9P is 15.3 kcal/mol. The tert-butyl analog 8B loses 2 mol of N2, showing that C-N homolysis greatly dominates over C-C homolysis. Nevertheless, we estimate that the latter process would occur with ΔG* (150°C) > 40.3 kcal/mol, which implies that the RSE of aliphatic hydrazonyl radical 9B is at least 6 kcal/mol below that of 9P and is little or no more than the RSE of the 1,1-dimethylallyl radical.
- Engel, Paul S.,Wang, Chengrong,Chen, Yanqin,Rüchardt, Christoph,Beckhans, Hans-Dieter
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- Reaction of Azoalkanes with Isolable Cation Radical Salts
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Three tertiary azoalkanes related in the sense acyclic, cyclic, and bicyclic are shown to evolve nitrogen upon oxidation with stable cation radical salts.Thus azo-tert-octane (ATO), 3,3,6,6-tetramethyl-1,2-diazacyclohexene (TMDAC), and 1,4-dimethyl-2,3-diazabicyclooct-2-ene (Me2DBO) react rapidly with thianthrenium perchlorate (Th(.1+)ClO4(1-)), tris(p-bromophenyl)aminium hexachloroantimonate (TBPA(.1+)SbCl6(1-)), and TBPA(.1+)SbF6(1-).The ether and olefin products, which are formed in high yield in CH2Cl2/MeOH solvent, are not those expected from the usual free-radical decomposition of azoalkanes but instead implicate carbocations.Althrough the reaction stoichiometry clearly requires 2 equiv of cation radical salt to one of azoalkane, the mechanism is not yet clearly defined.A complication in these studies is found in the ability of certain cation radical salts to oxidize more azoalkane than expected based on the 2:1 stoichiometry.
- Engel, Paul S.,Robertson, Donald M.,Scholz, John N.,Shine, Henry J.
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p. 6178 - 6187
(2007/10/02)
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- The Me3Si Substituent Effect on the Reactivity of Silanes. Structural Correlations between Silyl Radicals and Their Parent Silanes
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Good linear correlations exist both between the bond dissociation energy of an Si-H bond and the corresponding SiH stretching frequency and between the (29)Si hyperfine splitting of a silicon-centered radical and J((29)Si-H) for the corresponding silane, when the successive substitution at the Si-H function takes place inside a family, i.e., (Me3Si)3-nSi(H)Men, n = 0-3.Explanations for these phenomena are advanced.Such structural correlations allow the characterization of (Me3Si)2Si(H)Me as a radical-based reducing agent with low hydrogen-donating abilities.Rate constants for the reaction of primary alkyl radicals with (Me3Si)2Si(H)Me have been measured over a range of temperatures by using competing unimolecular radical reactions as timing devices.The radical trapping abilities of this silane and other common radical-based reducing agents are compared.
- Chatgilialoglu, C.,Guerrini, A.,Lucarini, M.
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p. 3405 - 3409
(2007/10/02)
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- Metal-Catalyzed Decarbonylation of Primary Aldehydes at Room Temperature
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The metal-catalyzed decarbonylation of primary aldehydes has been achieved at room temperature in THF solvent by utilization of catalytic amounts of Rh(PPh3)3Cl (2, 5 mol percent), in conjunction with stoichiometric amounts of diphenylphosphoryl azide (DPPA, 4).
- O'Connor, Joseph M.,Ma, Junning
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p. 5075 - 5077
(2007/10/02)
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- Tris(trimethylsilyl)silane as a Radical-Based Reducing Agent in Synthesis
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Tris(trimethylsilyl)silane is an effective reducing agent for organic halides, selenides, xanthates, and isocyanides, as well as an effective hydrosilylating agent for dialkyl ketones and alkenes.The silane functions as a mediator in the formation of intermolecular carbon-carbon bonds via radicals and allows a variety of organic substrates to be used as alkyl radical precursors.Absolute rate constants for the reaction of (Me3Si)3Si* radicals with a variety of organic compounds have been measured in solution by laser flash photolysis.At 294 K rate constants are >5 x 107 M-1 s-1 for C=C double bonds that are activated by neighboring ?-electron systems or by electron-withdrawing groups.For other substrates, reactivities decreased in the order xanthate > selenide > isocyanide > nitro > sulfide.
- Ballestri, M.,Chatgilialoglu, C.,Clark, K. B.,Griller, D.,Giese, B.,Kopping, B.
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p. 678 - 683
(2007/10/02)
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- Photochemistry of Azocyclopropane
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trans-Azocyclopropane (1t) has been irradiated in the gas phase at 254 nm and in hydrocarbon solution at several wavelengths.As with most acyclic azoalkanes, the dominant reaction is isomarization to the cis-azoalkane 1c.In the gas phase or with short wavelength light, 1t undergoes competitive C-N homolysis, giving cyclopropyl radicals, and ring fragmentation to ethylene.Triplet-sensitized isomerization of the azo linkage proceeds with unusually high efficiency (Φt->c=0.2), but no experimental support could be found for the notion that cyclopropane ring cleavage leads to azo group isomerization.Since azocyclopropane behaves as a "reluctant azoalkane" that undergoes multiple photoreactions, it is not a particularly useful source of cyclopropyl radicals.
- Engel, Paul S.,Bodager, Gregory A.
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p. 4748 - 4758
(2007/10/02)
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- Reactions of 1,1,3,3-Tetramethylcyclobutane on Evaporated Metal Films
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Reactions of 1,1,3,3-tetramethylcyclobutane (TMCB)-hydrogen mixtures on evaporated metal films have shown that both ring scission to 2,2,4-trimethylpentane (TMP) and ring enlargement to 1,1,3-trimethylcyclopentane (TMCP) are dominant on sintered platinum films, while ring scission to TMP predominates on sintered palladium and on unsintered molybdenum films.Unsintered tantalum and molybdenum films gave a large production of iC4 hydrocarbon, particularly above ca. 500 K: ring enlargement was a minor reaction found particularly with tantalum.The homogeneous reaction of TMCB giving a large iC4 production sets in at 600 K.The possibility, suggested by the product distribution, that the reaction of TMCB on Mo and Ta is a metal-assisted free-radical reaction is examined.While it may not be completely excluded that the catalysed ring enlargement on Pt and Pd is a free-radical reaction it is argued that only the previously proposed Rooney-Samman bond-shift mechanism accommodates without added qualifications published facts on bond shifts, including those at quaternary carbon atoms, and also ring enlargements.
- Clarke, John K. A.,Hegarty, Bernard F.,Rooney, John J.
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p. 2511 - 2518
(2007/10/02)
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- THERMISCHER ZERFALL VON Β-PHENYL UND Β,Β-DIPHENYL-NITROALKANEN
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Elimination of nitrous acid is the exclusive reaction path for the thermal decomposition of the nitroalkanes 1, 2 and 5.Homolytic CC-cleavage cannot compete.A concerted β-elimination is the favoured mechanism.
- Fritzsche, Katharina,Beckhaus, Hans-Dieter,Ruechardt, Christoph
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p. 2805 - 2808
(2007/10/02)
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- CONTRIBUTION A L'ETUDE DES REACTIONS DE COMBINAISON DES RADICAUX ALCOYLE TERTIAIRES EN PHASE SOLIDE
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Disproportionation/combination ratios of self-reacting t-alkyl radicals are estimated in solid phase at low temperature.The low temperature solid state limit was estimated to be 7-25, this value is considerably lower than ratios of the literature (100 to 500) and is compatible with the FISCHER limit in liquid state.In the present work, the ratios are determined by product analysis from the gamma radiolysis of isobutane.
- Gourdin-Serveniere, C.,Fontaine, L. M.,Tilquin, B.
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p. 177 - 188
(2007/10/02)
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- ORGANOBORANES FOR SYNTHESIS. 1. PROTONOLYSIS OF TRIALKYLBORANES. A CONVENIENT NON-CATALYTIC CONVERSION OF ALKENES INTO SATURATED COMPOUNDS via HYDROBORATION-PROTONOLYSIS
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The protonolysis of trialkylboranes with carboxylic acids proceeds very rapidly for the first group, somewhat slower for the second, but requires elevated temperatures for removal of the third.A close examination of the protonolysis of representative symmetrical, as well as mixed trialkylboranes, reveals that the steric requirements of the alkyl groups attached to boron play an important role in the rate.Secondary alkyl groups protonolyze less readily than primary alkyl groups.More hindered alkyl groups are still more resistant.Since the hydroboration-protonolysis sequence involves relatively mild conditions, this procedure can be applied for hydrogenating olefinic derivatives containing labile groups, such as active sulfur, halogen and nitrogen functionalities.The stereochemistry of protonolysis has been established via deuteroboration of norbornene and deuterolysis of the product.It is evident that protonolysis proceeds with retention of configuration at the migrating carbon.Partially alkylated boranes can be used for hydroboration-protonolysis with improved regioselectivity.Subsequent protonolysis of the resulting mixed trialkylboranes provides the desired alkanes in good yields.Products sensitive to the action of hot acetic acid offer difficulties.For example, when this procedure was applied to the preparation of 1-menthene from d-limonene, the product was racemic.
- Brown, Herbert C.,Murray, Kenneth J.
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p. 5497 - 5504
(2007/10/02)
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- DENITROHYDROGENATION OF ALIPHATIC NITRO COMPOUNDS AND A NEW USE OF ALIPHATIC NITRO COMPOUNDS AS RADICAL PRECURSORS
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Aliphatic nitro groups are replaced by hydrogen on treatment with tributyltin hydride which proceeds via free radical chain processes.As the nitro group is selectively denitrated and other reducible groups are not affected with tributyltin hydride, this reaction can be used as a method for removing the nitro group from polyfunctional compounds.The radical intermediates generated via denitration can be also used for the carbon-carbon bond forming reactions.
- Ono, Noboru,Miyake, Hideyoshi,Kamimura, Akio,Hamamoto, Isami,Tamura, Rui,Kaji, Aritsune
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p. 4013 - 4024
(2007/10/02)
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- Mecanisme de l'alkylation de l'isobutane par le propene sur zeolithe II. Etude des etapes elementaires de la reaction a l'aide de molecules marquees au carbone-13
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The mechanisms involved during the alkylation of isobutane by propene have been studied using carbon-13 labelled molecules.Several parallel reactions can lead to a same hydrocarbon.The carbon-13 distributions and structures of all the products can be explained by bimolecular processes between a limited number of species.These species are C3 and C4 olefins and ions and strongly adsorbed residues in which the tracer atoms lie in definite positions.
- Daage, Michel,Fajula, Francois
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p. 160 - 168
(2007/10/02)
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- Chemistry of the tert-Butyl Radical: Polar Character, ρ Value for Reaction with Toluenes, and the Effect of Radical Polarity on the Ration of Benzylic Hydrogen Abstraction to Addition to Aromatic Rings
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We have reexamined the reactions of tert-butyl radicals with toluenes and have obtained a ρ value of 0.49 +/- 0.04 at 80 deg C.The new, independent system involves the quantification of all of the principal products from the reaction of tert-butyl radicals with mixtures of toluene and substituted toluene.Five major products contain benzyl fragments and are formed in significant yields: two symmetrical bibenzyls, the cross bibenzyl, and the two neopentylbenzenes that result from combination of tert-butyl and the two benzyl radicals.Attack on the side chain is a major reaction of free tert-butyl radicals and is the only significant reaction that they undergo other than cage and termination reactions. tert-Butyl radicals do not add to the ring of toluenes.Data on the relative rates of addition to benzenes and hydrogen abstraction from toluenes are collected for a series of radicals including hydrogen atoms; methyl, isopropyl, and tert-butyl radicals; and p-nitrophenyl, p-bromophenyl, and phenyl radicals.The data demonstrate that more electrophilic radicals have a larger tendency to add to rings whereas more nucleophilic radicals have a larger tendency to abstract benzylic hydrogens.
- Pryor, William A.,Tang, Felicia Y.,Tang, Robert H.,Church, Daniel F.
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p. 2885 - 2891
(2007/10/02)
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- Disproportionation-Combination Reactions of Caged Geminate Radical Pairs Formed from the Photodecomposition of 2,2'-Azoisobutane. Anisotropic Reorientation of tert-Butyl Radicals in Viscous Media and Birth Effects in Very Viscous Media
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The solvent viscosity dependence of the self-termination reactions of tert-butyl radical pairs generated from the photolysis of 2,2'-azoisobutane, in a number of inert solvents admixed with thiophenol, shows a linear relationship between the cage efficiency, 1/cage yield, and fluidity, 1/η, of the solvent.The viscosity dependence of the ratio of disproportionation/combination rate constants, kd/kc, for these cage reactions was compared to the values observed for the reactions of encounter pairs generated by the photolysis of di-tert-butyl ketone.At viscosities between 0.5 and 2.7 cP the kd/kc ratios obtained for geminate radical pairs were the same as those obtained from the reaction of the encounter pairs, while at higher viscosities of 12-808 cP the orientation of the geminately formed radicals at birth appeared to bias the radicals to undergo a higher proportion of combination.
- Tanner, Dennis D.,Rahimi, Parviz M.
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p. 225 - 229
(2007/10/02)
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