- Adsorptive interaction between 1,5-pentanediol and MgO-modified ZrO2 catalyst in the vapor-phase dehydration to produce 4-penten-1-ol
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Vapor-phase catalytic dehydration of 1,5-pentanediol (1,5-PDO) was investigated over monoclinic ZrO2 catalysts modified with basic oxides. An unsaturated alcohol, 4-penten-1-ol (4P1OL), was produced together with the formation of tetrahydropyran, δ-valerolactone, 1,4-pentadiene, pentanal, 1-pentanol, and 5-hydroxypentanal, etc. Among the modified ZrO2 catalysts, only ZrO2 modified with MgO enhanced the selectivity to 4P1OL efficiently. The most active modified catalyst was found to have 20 mol% MgO and a calcination at 800 °C (MgO/ZrO2), and the selectivity of 4P1OL exceeded 83% at 400 °C. A pulse adsorption measurement of several chemicals clarified adsorptive interaction between a reactant and a catalyst at 220 °C: the interaction between 1,5-PDO and MgO/ZrO2 was stronger than the other adsorbates and catalysts. Another strong adsorptive interaction between 1,4-butanediol and CaO/ZrO2, which was effective in the dehydration of 1,4-butanediol to produce 3-buten-1-ol, was also observed.
- Duan, Hailing,Unno, Masaki,Yamada, Yasuhiro,Sato, Satoshi
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Read Online
- Hydrogenation of 2,3-dihydropyran to tetrahydropyran
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The optimum conditions for the hydrogenation of 2,3-dihydropyran to tetrahydropyran on an industrial nickel-chromium catalyst under flow and periodic conditions were found. A regression model for the process was found. The results of hydrogenation of 2,3-dihydropyran by means of a flow reactor and an autoclave of the Vishnevskii type are compared.
- Kuplenieks,Kreile,Slavinskaya,Avots
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Read Online
- Enhancement of cyclic ether formation from polyalcohol compounds in high temperature liquid water by high pressure carbon dioxide
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Cyclic ethers were produced by a dehydration reaction of polyalcohol compounds in high temperature liquid water, which was accelerated by the presence of carbon dioxide dissolved in the water. 3-hydroxytetrahydrofuran was produced by the dehydration of 1,2,4-butanetriol. Both tetrahydrofurfuryl alcohol and 3-hydroxytetrahydropyran were produced by the dehydration of 1,2,5-pentanetriol. Five-membered cyclic ethers were formed faster than six-membered cyclic ethers and the formation rates of the cyclic ethers depended strongly on the structure of the polyalcohol compounds. The position of the hydroxyl groups is crucial for the efficient intramolecular dehydration.
- Yamaguchi, Aritomo,Hiyoshi, Norihito,Sato, Osamu,Bando, Kyoko K.,Shirai, Masayuki
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Read Online
- Visible-Light-Enhanced Cobalt-Catalyzed Hydrogenation: Switchable Catalysis Enabled by Divergence between Thermal and Photochemical Pathways
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The catalytic hydrogenation activity of the readily prepared, coordinatively saturated cobalt(I) precatalyst, (R,R)-(iPrDuPhos)Co(CO)2H ((R,R)-iPrDuPhos = (+)-1,2-bis[(2R,5R)-2,5-diisopropylphospholano]benzene), is described. While efficient turnover was observed with a range of alkenes upon heating to 100 °C, the catalytic performance of the cobalt catalyst was markedly enhanced upon irradiation with blue light at 35 °C. This improved reactivity enabled hydrogenation of terminal, di-, and trisubstituted alkenes, alkynes, and carbonyl compounds. A combination of deuterium labeling studies, hydrogenation of alkenes containing radical clocks, and experiments probing relative rates supports a hydrogen atom transfer pathway under thermal conditions that is enabled by a relatively weak cobalt-hydrogen bond of 54 kcal/mol. In contrast, data for the photocatalytic reactions support light-induced dissociation of a carbonyl ligand followed by a coordination-insertion sequence where the product is released by combination of a cobalt alkyl intermediate with the starting hydride, (R,R)-(iPrDuPhos)Co(CO)2H. These results demonstrate the versatility of catalysis with Earth-abundant metals as pathways involving open-versus closed-shell intermediates can be switched by the energy source.
- Mendelsohn, Lauren N.,MacNeil, Connor S.,Tian, Lei,Park, Yoonsu,Scholes, Gregory D.,Chirik, Paul J.
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p. 1351 - 1360
(2021/02/01)
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- Ring-Closing Metathesis of Aliphatic Ethers and Esterification of Terpene Alcohols Catalyzed by Functionalized Biochar
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Functionalized biochars, renewable carbon materials prepared from waste biomass, can catalyze transformations of a range of oxygen-containing substrates via hydrogen-bonding interactions. Good conversions (up to 75.2 %) to different O-heterocycles are obtained from ring-closing C?O/C?O metathesis reactions of different aliphatic ethers under optimized conditions using this heterogeneous, metal-free, and easy separable catalyst. The diversity in the sorts of O-containing feedstocks is further demonstrated by the utilization of functionalized biochar to promote the esterification of terpene alcohols, an important reaction in food and flavor industries. Under the optimized conditions, full conversions to various terpene esters are obtained. Moreover, both of the reactions studied herein are performed under neat conditions, thus increasing the overall sustainability of the process described.
- Kerton, Francesca M.,MacQuarrie, Stephanie L.,Vidal, Juliana L.,Wyper, Olivia M.
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supporting information
p. 6052 - 6056
(2021/12/10)
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- Hydrogen-Bonding Catalyzed Ring-Closing C?O/C?O Metathesis of Aliphatic Ethers over Ionic Liquid under Metal-Free Conditions
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O-heterocycles have wide applications, and their efficient and green synthesis is very interesting. Herein, we report hydrogen-bonding catalyzed ring-closing metathesis of aliphatic ethers to O-heterocycles over ionic liquid (IL) catalyst under metal- and solvent-free conditions. The IL 1-butylsulfonate-3-methylimidazolium trifluoromethanesulfonate ([SO3H-BMIm][OTf]) is discovered to show outstanding performance, better than the reported catalysts. An interface effect plays an important role in mediating the reaction rate due to the immiscibility between the products and the IL catalyst, and the products can be spontaneously separated. NMR analysis and DFT calculation suggest that a pair of cation and anion of [SO3H-BMIm][OTf] could form three strong H-bonds with an ether molecule, which catalyze the ether transformation via a cyclic oxonium intermediate. A series of O-heterocycles including tetrahydrofurans, tetrahydropyrans, morpholines and dioxane can be obtained from their corresponding ethers in excellent yields (e.g., >99 %). This work opens an efficient and metal-free way to produce O-heterocycles from aliphatic ethers.
- Wang, Huan,Zhao, Yanfei,Zhang, Fengtao,Wu, Yunyan,Li, Ruipeng,Xiang, Junfeng,Wang, Zhenpeng,Han, Buxing,Liu, Zhimin
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p. 11850 - 11855
(2020/05/16)
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- Novel method for preparing oxygen heterocyclic compound through ionic liquid catalysis
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The invention discloses a novel method for preparing an oxygen heterocyclic compound through ionic liquid catalysis. The ionic liquid catalytic system has the advantages of high efficiency, simplicity, mild reaction conditions, no metal participation, no by-product, simple separation and the like and can efficiently catalyze fatty diether metathesis cyclization to prepare an oxygen heterocyclic compound and has very high industrial application value.
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Paragraph 0039-0059
(2020/08/02)
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- Efficient one-pot conversion of furfural into 2-methyltetrahydrofuran using non-precious metal catalysts
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2-methyltetrahydrofuran, a biomass-derived chemical, is an important solvent with broad applications in organic chemistry. In this study, one-pot conversion of furfural into 2-methyltetrahydrofuran over non-precious metal catalysts was achieved by two-stage packing in a single reactor. The first stage converted furfural into 2-methylfuran over Co-based catalysts, and the second stage converted 2-methylfuran into 2-methyltetrahydrofuran over Ni-based catalysts. In order to reveal the reaction pathway and mechanism of this process, the hydrogenation reactions of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol were also carefully investigated. It is discovered that the conversion of furfural into 2-methylfuran could be catalyzed by Lewis acid sites, which was confirmed by a correlation between 2-methylfuran production rate and Lewis acid site density. Also, a mechanism on the direct conversion of furfural into 2-methylfuran without forming furfuryl alcohol as the intermediate is proposed. The experimental results of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol hydrogenation/hydrodeoxygenation over various catalysts provided valuable information on the future design of 2-methyltetrahydrofuran catalyst.
- Jia, Xinxin,Li, Cuiqing,Liu, Ping,Song, Yongji,Sun, Luyang,Wang, Hong,Zhang, Chen,Zhang, Wei
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- Improved Pd/Ru metal supported graphene oxide nano-catalysts for hydrodeoxygenation (HDO) of vanillyl alcohol, vanillin and lignin
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Pd and Ru nanoparticles supported on graphene oxide (GO) [Pd?GO and Ru?GO] and bimetallic [Pd/Ru?GO] were prepared and well characterized by XRD, FT-IR, EDS, TEM, XPS and ICP-AES analyses. The prepared nano-catalysts were tested for hydrodeoxygenation (HDO) of lignin monomer molecules-vanillyl alcohol and vanillin. In comparison with previously reported methods, Ru?GO and bimetallic Pd/Ru?GO catalysts showed high activity and selectivity, under milder conditions, at room temperature and 145 psi H2 pressure, for the formation of p-creosol, a value added product, as a potential future biofuel with antibacterial and anti-insecticidal properties. The multifold advantages of both these catalysts are in terms of reduced catalyst loading with a lower metal content and ambient temperture conditions resulting in higher conversion of the starting material. Furthermore, the efficacy of the developed methodology using Ru?GO and bimetallic Pd/Ru?GO catalysts under the optimized conditions was tested on the phenolic components of commercial lignin obtained by photo-catalytic fragmentation using TiO2, to obtain a mixture after HDO which contained vanillyl alcohol and p-creosol among others, as indicated by HPLC-MS analysis.
- Arora, Shalini,Gupta, Neeraj,Singh, Vasundhara
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supporting information
p. 2018 - 2027
(2020/04/07)
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- Controlling Sugar Deoxygenation Products from Biomass by Choice of Fluoroarylborane Catalyst
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The feedstocks from biomass are defined and limited by nature, but through the choice of catalyst, one may change the deoxygenation outcome. We report divergent but selective deoxygenation of sugars with triethylsilane (TESH) and two fluoroarylborane catalysts, B(C6F5)3 and B(3,5-CF3)2C6H3)3 (BAr3,5-CF3). To illustrate, persilylated 2-deoxyglucose shows exocyclic C-O bond cleavage/reduction with the less sterically congested BAr3,5-CF3, whereas endocyclic C-O bond cleavage/reduction predominates with the more Lewis acidic B(C6F5)3. Chiral furans and linear polyols can be selectively synthesized depending on the catalysts. Mechanistic studies demonstrate that the resting states of these catalysts are different.
- Seo, Youngran,Lowe, Jared M.,Gagné, Michel R.
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p. 6648 - 6652
(2019/08/26)
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- Iridium complex catalytic ring lactone hydrogenation [...] method
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The present invention provides one kind of iridium complex catalytic ring lactone hydrogenation [...] method, organic chemical technical field. The present invention is to ring lactone as raw materials, iridium complex as the catalyst hydrogenation reaction, in particular in accordance with the following steps: that the intrauterine lactone, iridium complex, the hydrogen gas as a reducing agent, the hydrogen reduction reaction, iridium complexes and ring lactone mass ratio is 0.00001 - 0.1; a hydrogen pressure of 1.0 - 10.0 mpa; the reaction temperature is 90 - 150 °C, the reaction time is: 0.5 - 72 h. The beneficial effects of the present invention: simple reaction operation, product selectivity and easy separation.
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Paragraph 0030-0031
(2019/07/04)
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- Transfer Hydrogenation of Alkenes Using Ethanol Catalyzed by a NCP Pincer Iridium Complex: Scope and Mechanism
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The first general catalytic approach to effecting transfer hydrogenation (TH) of unactivated alkenes using ethanol as the hydrogen source is described. A new NCP-type pincer iridium complex (BQ-NCOP)IrHCl containing a rigid benzoquinoline backbone has been developed for efficient, mild TH of unactivated C-C multiple bonds with ethanol, forming ethyl acetate as the sole byproduct. A wide variety of alkenes, including multisubstituted alkyl alkenes, aryl alkenes, and heteroatom-substituted alkenes, as well as O- or N-containing heteroarenes and internal alkynes, are suitable substrates. Importantly, the (BQ-NCOP)Ir/EtOH system exhibits high chemoselectivity for alkene hydrogenation in the presence of reactive functional groups, such as ketones and carboxylic acids. Furthermore, the reaction with C2D5OD provides a convenient route to deuterium-labeled compounds. Detailed kinetic and mechanistic studies have revealed that monosubstituted alkenes (e.g., 1-octene, styrene) and multisubstituted alkenes (e.g., cyclooctene (COE)) exhibit fundamental mechanistic difference. The OH group of ethanol displays a normal kinetic isotope effect (KIE) in the reaction of styrene, but a substantial inverse KIE in the case of COE. The catalysis of styrene or 1-octene with relatively strong binding affinity to the Ir(I) center has (BQ-NCOP)IrI(alkene) adduct as an off-cycle catalyst resting state, and the rate law shows a positive order in EtOH, inverse first-order in styrene, and first-order in the catalyst. In contrast, the catalysis of COE has an off-cycle catalyst resting state of (BQ-NCOP)IrIII(H)[O(Et)···HO(Et)···HOEt] that features a six-membered iridacycle consisting of two hydrogen-bonds between one EtO ligand and two EtOH molecules, one of which is coordinated to the Ir(III) center. The rate law shows a negative order in EtOH, zeroth-order in COE, and first-order in the catalyst. The observed inverse KIE corresponds to an inverse equilibrium isotope effect for the pre-equilibrium formation of (BQ-NCOP)IrIII(H)(OEt) from the catalyst resting state via ethanol dissociation. Regardless of the substrate, ethanol dehydrogenation is the slow segment of the catalytic cycle, while alkene hydrogenation occurs readily following the rate-determining step, that is, β-hydride elimination of (BQ-NCOP)Ir(H)(OEt) to form (BQ-NCOP)Ir(H)2 and acetaldehyde. The latter is effectively converted to innocent ethyl acetate under the catalytic conditions, thus avoiding the catalyst poisoning via iridium-mediated decarbonylation of acetaldehyde.
- Wang, Yulei,Huang, Zhidao,Leng, Xuebing,Zhu, Huping,Liu, Guixia,Huang, Zheng
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supporting information
p. 4417 - 4429
(2018/04/05)
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- Production of 1,5-pentanediol via upgrading of tetrahydrofurfuryl alcohol
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A method of making 1,5-pentanediol from tetrahydrofurfural alcohol. The method includes the steps of dehydrating tetrahydrofurfural alcohol (THFA) to dihydropyran (DHP); hydrating at least a portion of the DHP to 2-hydroxy-tetrahydropyran (2-HY-THP) in the presence of a solid acid catalyst; and hydrogenating at least a portion of the 2-HY-THP to 1,5-pentanediol. The method can be conducted entirely in the absence of noble metal catalysts.
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Page/Page column 21; 22
(2018/10/11)
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- C?O Hydrogenolysis of Tetrahydrofurfuryl Alcohol to 1,5-Pentanediol Over Bi-functional Nickel-Tungsten Catalysts
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In this study, we report a series of bimetallic Ni?WOx catalyst for the ring-opening of THFA into 15PDO. The structure-performance relationship of the catalysts was discussed based on extensive characterization using techniques such as BET, H2-TPR, NH3-TPD, Pyr-IR, IPA-TPD-MS, XRD, XPS and EXAFS/XANES. The acidity measurements show that higher W density leads to the higher amount of acid density, which could be assigned to the creation of Lewis acid sites mainly on the surface of the calcined catalysts. H2-TPR profiles of Ni?WOx catalysts show that there is a strong interaction between Ni and W species, enhancing the reducibility of WOx. XRD measurements of calcined Ni?WOx catalysts reveal that the dispersion of Ni particles is enhanced after addition of WOx species. After reduction, different peaks corresponding to metallic Ni and WO3?x are identified for 10Ni?WOx catalysts, as well as new peak assigned to Ni?W intermetallic phase on 10Ni?30WOx catalyst. The formation of Ni?W intermetallic phase was further proved using XPS and EXAFS studies. THFA hydrogenolysis was also conducted under aqueous-phase conditions over Ni?WOx catalysts, yielding up to 47 % selectivity to 15PDO, along with a highest combined C5 polyols (i. e., 15PDO and 125PTO) selectivity of approximately 64 %. However, the Ni?WOx catalytic system suffers from deactivation process due to the hydrothermal dissolution of the active phase. Further investigation reveals the better stability of metallic tungsten and Ni?W intermetallic phase (Ni4W) against leaching since their corresponding peaks in the XRD patterns of spent catalysts remains nearly unchanged. Finally, 1,4-dioxane as an organic solvent was employed in THFA hydrogenolysis reaction, resulting in different product distribution, with a THP yield of around 54 %. The catalyst crystalline structure is preserved because of very low Ni and W leaching when 1,4-dioxane is used as solvent.
- Soghrati, Elmira,Kok Poh, Chee,Du, Yonghua,Gao, Feng,Kawi, Sibudjing,Borgna, Armando
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p. 4652 - 4664
(2018/10/02)
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- An ether compound of green high-efficient synthetic method (by machine translation)
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The invention discloses an ether compound of green high-efficient synthetic method, energy-saving environmental protection, comprising: mild reaction system, uses aldehyde, silane as the starting material, under the action of the silver salt in a price, for in solvent-free conditions, through reducing the - coupling - cheng mi reaction, realization of high efficiency alcohol of preparation. Synthesis method of the invention has the advantages of low dosage of catalyst, solvent-free, conversion and high yield, the reaction time is short, safe and stable, easy to operate, the product only distillation purification without any additional organic solvent, the whole range of green, environmental protection, high efficiency and the like, can overcome the defects of the prior art, it has very good industrial application value. (by machine translation)
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Paragraph 0050
(2018/07/07)
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- Iron-Catalyzed Ring-Closing C?O/C?O Metathesis of Aliphatic Ethers
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Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring-closing reactions. Herein, we report an iron-catalyzed ring-closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.
- Biberger, Tobias,Makai, Szabolcs,Lian, Zhong,Morandi, Bill
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supporting information
p. 6940 - 6944
(2018/05/14)
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- Dehydration of 1,5-Pentanediol over Na-Doped CeO2 Catalysts
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The effects of CeO2 doped with Na on the dehydration of 1,5-pentanediol were studied by using a fixed-bed reactor at two different temperatures (350 and 400 °C) and atmospheric pressure. For characterization, BET surface area, hydrogen temperature-programmed reduction, CO2 temperature-programmed desorption, and diffuse reflectance infrared Fourier transform spectroscopy techniques were utilized. The conversion of the diol on CeO2 was found to depend on Na loading. The selectivity to the desired product (i.e., unsaturated alcohol) increased and the selectivity to undesired products (i.e., tetrahydropyran, tetrahydropyran-2-one, cyclopentanol and cylopentanone) decreased with increasing Na content on CeO2. The basicity of hydroxyl groups or surface oxygen on CeO2 was altered with the addition of Na, and controlled the dehydration reaction pathway.
- Gnanamani, Muthu Kumaran,Jacobs, Gary,Martinelli, Michela,Shafer, Wilson D.,Hopps, Shelley D.,Thomas, Gerald A.,Davis, Burtron H.
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p. 1148 - 1154
(2018/02/12)
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- Synthesis of cyclic ethers from diols in the presence of copper catalysts
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A number of cyclic ethers, namely tetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, oxepane, oxocane, and 1,4-oxathiane, have been synthesized in high yields by intramolecular dehydration of diols in the presence of copper-based catalysts.
- Bayguzina,Gimaletdinova,Khusnutdinov
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p. 1840 - 1843
(2018/02/06)
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- Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters
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Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. An assist from Al: A bifunctional catalyst system consisting of a Ru/phosphine complex and aluminum triflate allows selective hydrogenation of esters to ethers. A variety of lactones were reduced to the desired products in good yields. The catalyst further provides a general method for the reduction of linear esters and reductive etherification of carboxylic acids with alcohols.
- Li, Yuehui,Topf, Christoph,Cui, Xinjiang,Junge, Kathrin,Beller, Matthias
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supporting information
p. 5196 - 5200
(2015/04/27)
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- Synthesis of common-sized heterocyclic compounds by intramolecular cyclization over halide cluster catalysts
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Five- to seven-membered common-sized heterocyclic compounds containing an oxygen, sulfur, or nitrogen were synthesized by the intramolecular condensation of α,ω-hydroxy, mercapto, or amino alkanes, respectively, over halide cluster complexes as a thermally stable molecular solid weak acid catalyst in the gas phase at temperatures ≥150 °C. From ω- mercapto and ω-amino alcohols, cyclic sulfides and amines were obtained, respectively. These unimolecular reactions are thermodynamically and kinetically favored.
- Nagashima, Sayoko,Sasaki, Tomoaki,Kamiguchi, Satoshi,Chihara, Teiji
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supporting information
p. 764 - 766
(2015/06/22)
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- Rapid ether and alcohol C-O bond hydrogenolysis catalyzed by tandem high-valent metal triflate + supported Pd catalysts
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The thermodynamically leveraged conversion of ethers and alcohols to saturated hydrocarbons is achieved efficiently with low loadings of homogeneous M(OTf)n + heterogeneous Pd tandem catalysts (M = transition metal; OTf = triflate; n = 4). For example, Hf(OTf)4 mediates rapid endothermic ether a? alcohol and alcohol a? alkene equilibria, while Pd/C catalyzes the subsequent, exothermic alkene hydrogenation. The relative C-O cleavage rates scale as 3 > 2 > 1. The reaction scope extends to efficient conversion of biomass-derived ethers, such as THF derivatives, to the corresponding alkanes.
- Li, Zhi,Assary, Rajeev S.,Atesin, Abdurrahman C.,Curtiss, Larry A.,Marks, Tobin J.
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supporting information
p. 104 - 107
(2014/01/23)
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- Modeling aqueous-phase hydrodeoxygenation of sorbitol over Pt/SiO 2-Al2O3
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In this paper, we investigated the effects of temperature, hydrogen partial pressure, and sorbitol concentration on the aqueous-phase hydrodeoxygenation (APHDO) of sorbitol over a bifunctional 4 wt% Pt/SiO2-Al 2O3 catalyst in a trickle bed reactor. APHDO involves four fundamental reactions: (1) hydrogenation; (2) dehydration; (3) C-C bond cleavage by dehydrogenation and decarbonylation; and (4) C-C bond cleavage by dehydrogenation and retro-aldol condensation. The main deoxygenation routes are decarbonylation and alcohol dehydration. Retro-aldol condensation plays a critical role in reducing the carbon number of the products. The key products in this system are C1-C6 n-alkanes, primary and secondary alcohols, and carbon dioxide. As shown in this paper, the reaction conditions can dramatically change the product selectivity for APHDO of biomass-derived feedstocks (e.g., sorbitol). A sorbitol hydrodeoxygenation reaction network was generated that predicts all of the 43 experimentally measured species. The reaction network consists of 4804 reactions and produces a total of 1178 distinct chemical species. The associated material balance equations were solved numerically to model the experimentally observed species as a function of temperature, concentration, and pressure. The model concentrations fit well the experimentally measured values, demonstrating that the model was accurately able to model the reaction families and capture the salient features of the experimental observations. The trend observed in this paper can be used for the optimization of reactors and new catalysts to selectively make targeted products by hydrodeoxygenation of biomass-derived feedstocks.
- Moreno, Brian M.,Li, Ning,Lee, Jechan,Huber, George W.,Klein, Michael T.
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p. 23769 - 23784
(2013/11/19)
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- Hydroformylation and hydroalkylcarbonylation of 3,4-dihydro[2H]pyran catalysed by Co2(CO)8 under syngas conditions
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In the cobalt-catalysed hydroformylation of 3,4-dihydro[2H]pyran, the influence of different reaction parameters such as time, pressure, triphenylphosphine addition, catalyst and substrate concentration has been investigated. 2-formyl-tetrahydropyran, tetrahydropyran and a hydroalkylcarbonylation product were the main reaction products. The selectivity towards 2-formyl-tetrahydropyran formation is favoured at constant catalyst and substrate concentration. The coordination of the pyran's oxygen to the cobalt atom seems to be an important intermediate for the formation of 2-formyl-tetrahydropyran. Different substrate or catalyst concentrations promote the formation of other reduced products. The addition of triphenylphosphine to the catalyst leads to a less active species, which decreases the yield and promotes the hydroalkylcarbonylation reaction.
- Arias, Jose L.,Sharma, Pankaj,Cabrera, Armando,Beristain, Fernando,Sampere, Rafael,Arizmendi, Cesar
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p. 787 - 792
(2013/10/22)
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- CATALYTIC DEHYDRATION OF ALCOHOLS AND ETHERS OVER A TERNARY MIXED OXIDE
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A ternary V—Ti—P mixed oxide is shown to catalytically dehydrate 2-methyl-tetrahydrofuran in high conversion to give piperylene, in good yield. Volatile products collected from this reaction contain piperylene in concentrations as high as 80 percent by weight. Dehydration of glycerol to acrolein in high conversion and moderate selectivity is also demonstrated. The catalyst is also shown to dehydrate other alcohols and ether substrates. The catalyst is resistant to deactivation and maintains activity between runs.
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Paragraph 0040; 0046
(2013/03/28)
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- Stable vapor-phase conversion of tetrahydrofurfuryl alcohol into 3,4-2H-dihydropyran
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Vapor-phase synthesis of 3,4-2H-dihydropyran (DHP) from tetrahydrofurfuryl alcohol (THFA) was investigated over acidic catalysts modified with transition metals. Catalytic activity of alumina was seriously deactivated in the reaction of THFA in nitrogen at 300 °C although the initial activity was high. Tetragonal ZrO2 showed the catalytic activity to produce DHP at 350 °C. Alumina modified with Cu exhibits stable catalytic activity with high selectivity to DHP under hydrogen flow conditions, and the optimum activity was obtained at CuO contents of 5-10 wt.%: the selectivity to DHP was as high as 85%. Prior to the reaction, CuO was reduced to metallic Cu, which probably works as a product remover together with hydrogen to prevent coke formation. The reaction pathway from THFA to DHP was discussed: it is speculated that THFA is initially rearranged into 2-hydroxytetrahydropyran, which rapidly dehydrated to DHP.
- Sato, Satoshi,Igarashi, Jun,Yamada, Yasuhiro
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p. 213 - 218
(2013/03/28)
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- Dehydration of 1,5-pentanediol over bixbyite Sc2-xYb xO3 catalysts
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Vapor-phase dehydration of 1,4- and 1,5-alkanediols was investigated over three scandium ytterbium mixed oxides, Sc2-xYbxO 3 (x = 0.5, 1.0, and 1.5), to produce the corresponding unsaturated alcohols. In the dehydration of
- Sato, Fumiya,Sato, Satoshi
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p. 129 - 133
(2013/01/13)
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- Direct synthesis of unsymmetrical ethers from alcohols catalyzed by titanium cation-exchanged montmorillonite
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Titanium-exchanged montmorillonite (Ti4+-mont) was found to act as an efficient heterogeneous catalyst for the etherification of a wide range of alcohols under mild reaction conditions. Ti4+-mont was reusable with retention of high efficiency and applicable to scale-up reaction conditions. The Royal Society of Chemistry 2012.
- Mitsudome, Takato,Matsuno, Tsuyoshi,Sueoka, Shoichiro,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information; experimental part
p. 610 - 613
(2012/04/23)
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- Photo-cross-linking of polymethacrylates with stilbene chromophores in the side chains
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Methacrylates (=2-methylpropenoates) 5 with (E)-stilbene (=(E)-1,2-diphenylethene) building blocks on tethers of variable length were prepared (Scheme 2) and polymerized (i.e., 5→6; Scheme 3) in the presence of AIBN (=2,2′-azobis(2-methylpropanenitrile). 4-[(E)-2-Phenylethenyl] phenyl acetate (7) as model compound established the cyclodimerization as a single irreversible photoreaction. i.e., (7→8-11; Scheme 4) in the absence of oxygen. The solution photolysis of the polymers 6 provided a similar result, whereby [2π+2π] cycloadditions of stilbene units of neighboring tethers predominated. On the contrary, the desired photo-cross-linking of chaines occurred in the irradiation of polymer films. Copyright
- Jahnke, Angelika,Beile, Bernhard,Meier, Herbert
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experimental part
p. 2111 - 2124
(2012/01/31)
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- PROCESS INCLUDING HYDROGENOLYSIS OF BIOMASS FOLLOWED BY DEHYDROGENATION AND ALDOL CONDENSATION FOR PRODUCING ALKANES
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A method comprises providing a bio-based feedstock; contacting the bio-based feedstock with a solvent in a hydrolysis reaction to form an intermediate stream comprising carbohydrates; contacting the intermediate stream with an aqueous phase reforming catalyst to form a plurality of oxygenated intermediates, wherein a first portion of the oxygenated intermediates are recycled to form the solvent; and contacting at least a second portion of the oxygenated intermediates with a condensation catalyst comprising a base functionality to form a fuel blend.
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Page/Page column 34-37
(2011/12/02)
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- CYCLIC ETHERS
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A process of preparing cyclic ethers is described. The process involves the reaction of at least one organic compound such as a dioi or a polyol which it has at least one pair of hydroxyl groups separated by 4 or 5 carbon atoms, and which is capable of being converted into an ether linkage, with an organic carbonate in the presence of a base. The base is an alkoxy, a carbonate or a hydroxide base or is a mixture of such bases. At least one of the hydroxyl groups of the organic compound is not a tertiary hydroxyl group.
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Page/Page column 10; 14
(2009/03/07)
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- Thermodynamic equilibria between polyalcohols and cyclic ethers in high-temperature liquid water
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Thermodynamic equilibrium constants between polyalcohols and cyclic ethers in water at 573 K were determined by measuring their concentrations after the long-term reaction in a batch reactor. Intramolecular dehydration reactions of polyalcohols were important for conversion of biomass-derived carbohydrates; however, the yields of products were limited by thermodynamic equilibria between polyalcohols and products. All the thermodynamic equilibrium constants were estimated by the long-term dehydration reaction of 1 mol ·dm-3 polyalcohol aqueous solutions at 573 K. The thermodynamic equilibrium constants between butanepolyols or pentanepolyols and five-membered or six-membered cyclic ethers were within a range from (39 to 337) mol ·dm-3.
- Yamaguchi, Aritomo,Hiyoshi, Norihito,Sato, Osamu,Bando, Kyoko K.,Masuda, Yoshio,Shirai, Masayuki
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experimental part
p. 2666 - 2668
(2010/07/08)
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- Catalytic synthesis of oxygenate from alcohol
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The present invention discloses a method for catalytic synthesis of oxygenate from alcohol. At first, a feeding material comprising at least one alcohol is provided. Next, a copper-containing catalyst is provided and the catalyst further comprises at least one metal element selected from the group consisting of the following: zinc, magnesium, and aluminum elements. Following that, a catalytic reaction of the feeding material over the copper-containing catalyst is carried out to synthesize at least one oxygenate.
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Page/Page column 4-8
(2008/06/13)
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- Rule of five cyclizations in 5-hexenyl radicals and photocycloadditions of 1,5-hexadienes: Effect of 4-oxa substitution
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The effect of 4-oxa substitution on the regiochemistry and rate of 5-hexenyl radical cyclizations was investigated, as a potential model for [2 + 2] photocycloadditions of 2-acyl-4-oxa-1,5-hexadienes. Increasing the electron density in the alkene decreases the rate of cyclization in the 4-oxa-hexejiyl radicals, relative to the all carbon analogs, but has little effect on the regioselectivity of the cyclization. The radical model does not reproduce the high degree of 1,6 closure, observed in the [2 + 2] photocycloadditions for 4-oxa-1,5-hexadiene la. However, the radical model does reinforce the interpretation that ground state conformational effects, engendered by substitution remote from the reacting centers have important rate consequences for cyclization reactions. Copyright
- Matlin, Albert R.,Brinton, Karen Feit,Nivaggioli, Belinda Tsao
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- PRODUCTION PROCESS OF TETRAHYDROPYRAN COMPOUND AND TETRAHYDROPYRAN COMPOUND PRODUCED BY THE PRODUCTION PROCESS
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The invention provides a production process of a tetrahydropyran compound, characterized by allowing 3,4-dihydro-2-alkoxy-2H-pyran compound or tetrahydro-2-alkoxy-2H-pyran compound which can be easily prepared through reaction between acrolein and alkylvinylether, with hydrogen in the presence of a catalyst containing an element of Groups VIII to X under acidic condition. The production process of the invention is useful for production of Grignard reaction solvent or polymer solvent and intermediate of organic compound.
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Page/Page column 24
(2008/06/13)
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- N-ureidoheterocycloalkyl-piperidines as modulators of chemokine receptor activity
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The present application describes modulators of CCR3 of formula (I): or pharmaceutically acceptable salt forms thereof, useful for the prevention of asthma and other allergic diseases.
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- Byrostatin analogues, synthetic methods and uses
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Biologically active compounds related to the bryostatin family of compounds, having simplified spacer domains and/or improved recognition domains are disclosed, including methods of preparing and utilizing the same.
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- NOVEL POTASSIUM CHANNEL AGONIST PRODUCED FROM TRICHODERMA VIRENS
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The present invention relates to novel potassium channel agonists which are useful in activating the calcium activated Maxi-K potassium channel in mammalian neuronal and smooth muscle tissue. The claimed compounds are of the general formula: In addition, a novel microbiological process for producing the claimed compounds is described.
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- Macrocyclic analogs and methods of their use and preparation
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The invention provides halichondrin analogs having pharmaceutical activity, such as anticancer or antimitotic (mitosis-blocking) activity, and methods of identifying agents that induce a sustained mitotic block in a cell after transient exposure of the cell to the agents.
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- Fragrance precursors
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The invention relates to fragrance precursors, In particular, the invention relates to the use of several classes of compounds which may act as fragrance precursors, e,g., in cosmetic products such as deodorants and antiperspirants and in laundry products such as detergents and fabric softners. These compounds are odorless, but upon contacting the skin as example, in skin care compositions or in personal care compositions, produce fragrances. The compounds also produce fragrances when used in the presence of lipases, e.g. as used in (laundry) detergents, thus providing a prolongation of the fabric scenting effect. The compounds under consideration are compounds of the formula I: The substituents are defined in the specification.
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- Method of resolving racemic mixtures
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PCT No. PCT/EP96/04030 Sec. 371 Date Feb. 26, 1998 Sec. 102(e) Date Feb. 26, 1998 PCT Filed Sep. 13, 1996 PCT Pub. No. WO97/11927 PCT Pub. Date Apr. 3, 1997A process for resolving racemates of compounds of the formula I in which a, A, B, D, E, F, M, Q and R have the meanings given in the description is described. The process is carried in a manner known per se but using the optical antipodes of derivatives of phenoxypropionic acid. Also described are salts of deprenyl, ephedrine or tetrahydropapaverine with a phenoxypropionic acid of the formula in which U and T have the meaning stated in the description, and which result as intermediate in the racemate resolution.
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- The continuous acid-catalyzed dehydration of alcohols in supercritical fluids: A new approach to the cleaner synthesis of acetals, ketals, and ethers with high selectivity
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We report a new continuous method for forming ethers, acetals and ketals using solid acid catalysts, DELOXAN ASP or AMBERLYST 15, and supercritical fluid solvents. In the case of ether formation, we observe a high selectivity for linear alkyl ethers with little rearrangement to give branched ethers. Such rearrangement is common in conventional syntheses. Our approach is effective for a range of n-alcohols up to n-octanol and also for the secondary alcohol 2-propanol. In the reaction of phenol with an alkylating agent, the continuous reaction can be tuned to give preferential O- or C- alkylation with up to 49% O-alkylation with supercritical propene. We also investigate the synthesis of a range of cyclic ethers and show an improved method for the synthesis of THF from 1,4-butandiol under very mild conditions.
- Gray, William K.,Smail, Fiona R.,Hitzler, Martin G.,Ross, Stephen K.,Poliakoff, Martyn
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p. 10711 - 10718
(2007/10/03)
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- Cyclodehydration of some 1,n-diols catalysed by sulfated zirconia
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Sulfated zirconia, a solid acid is found to be a good catalyst in the cyclodehydration of several diols.
- Wali, Anil,Pillai, S. Muthukumaru
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p. 326 - 327
(2007/10/03)
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- Mutual catalytic conversions of unsubstituted furan and pyran systems
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The conversions of furan, di- and tetrahydrofuran, and di- and tetrahydropyran on a molybdenum catalyst in a hydrogen atmosphere have been investigated. The studied cyclic systems readily undergo mutual conversions at 125-215°C and also undergo a hydrogenation-dehydrogenation reaction. Expansion of the unsubstituted furan rings to pyran without the introduction into the reaction medium of components capable of generating methyl radicals are described by us for the first time.
- Anderson,Simonyan,Lukevics
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p. 1406 - 1408
(2007/10/03)
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- Hydrogen bonding Part 44 1Thermodynamics of complexation of 3,5-dichlorophenol with ketones and ethers in cyclohexane: The badger-Bauer relationship
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Equilibrium constants for 1 : 1 hydrogen bond complexation between 3,5-dichioropheno' (DCP) and 17 ketones and 12 ethers in cyclohexane solution have been obtained by an FTIR method that takes into account both diiaerization of the acid and formation of 2 :1 complexes. Enthalpies of complexation for the same ketones and ethers have been determined by a calorimeiric method, leading to values of log K, AG, AH and AS0 for 1 :1 complexation in the 29 systems, as well as log K2 for the 2 :1 complexation between 2 mol of acid and 1 mol of base. For the ketone systems there is very little variation in the three thermodynamic parameters with alkyl substitution, but for the ethers there are systematic variations depending on the alkyl substituent or if the ethers are cyclic. Values of the OH stretching frequency in the DCP complexes with the ketones and ethers in cyclohexane have been obtained. The band shapes for the DCP-ketone complexes are very asymmetric, possibly due to the presence of stereoisomeric complexes, but the VOH band for DCP-ether complexes is symmetric and very suitable for the evaluation of any relationship between v()H and A/f. It is found that for the complexation of DCP with the 12 aliphatic ethers in cyclohexane, there is almost no connection between the calorimetrically determined AH° values and values of AvOH.
- Abraham, Michael H.,Prior, David V.,Schulz, Ronald A.,Morris, Jeffrey J.,Taylor, Peter J.
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p. 879 - 885
(2007/10/03)
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- Lithium diisopropylamide solvated by monodentate and bidentate ligands: Solution structures and ligand binding constants
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6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15N]LDA) in toluene/pentane solutions containing a variety of mono- and polydentate ligands are reported. LDA forms exclusively dimers in the presence of n-BuOMe, Et2O, t-BuOMe, THF, 2- methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, dimethoxyethane, N,N,N',N'-tetramethylethylenediamine, and MeOCH2CH2NR2 (NR2 = NMe2, NEt2, pyrrolidino). Addition of 1,2-dipyrrolidinoethane and (2-pyrrolidinoethyl)dimethylamine provides monomer-dimer mixtures. Treatment of LDA with trans-N,N,N',N'-tetramethylcyclohexanediamine (TMCDA) or trans- 1-(dimethyl-amino)-2-isopropoxycyclohexane in hydrocarbons afford exclusively monomers. Sparteine binds only reluctantly, giving a mixture of unsolvated oligomers and monomer. Competitions of the ethereal ligands vs TMCDA afford binding constants and associated free energies for dimer solvation which are correlated with those obtained previously for lithium hexamethyldisilazide.
- Remenar, Julius F.,Lucht, Brett L.,Collum, David B.
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p. 5567 - 5572
(2007/10/03)
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- Compounds and process
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A compound of formula (I): STR1 n which M is a transition metal ion; A is a counter-ion if required; r, s and t are independently 0 to 3 such that r+s+t is in the range of 1 to 3; Ra, Rb, Rc are each independently hydrogen or CH2 OR' where R' is hydrogen or an organic group; B and E are independently oxygen, CH2, NRd in which Rd is alkyl, hydrogen, alkylcarbonyl, or arylcarbonyl or SOn where n is 0 or an integer 1 or 2, with the proviso that B and E are not simultaneously CH2 and that when B is oxygen, NRd or SOn, then r cannot be 0, and when E is oxygen, NRd or SOn, then t cannot be 0; R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently hydrogen, alkyl or alkoxy.
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- Multi-substituted tetrahydrofurans
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Novel odorant compositions which are characterized by a content of one or more compounds selected from the group consisting of tetrahydrofurans of structures 1 or 2, or tetrahydropyrans of structure 3. STR1 wherein R can be an acyclic, where acyclic refers to a chain of at least four carbon atoms substituted with at least three methyl groups in the chain, carbocyclic, where carbocyclic refers to a ring of 5-8 carbon atoms, and with at least two methyl groups on the ring, or bicyclic where bicyclic refers to two carbon rings, each ring having between 5-8 carbon atoms fused together, substituted with at least two methyl groups, and where R1 =CH3, or higher alkyl group, R2 =H, CH3, or higher alkyl group, R3 =H, or CH3, R4 and R5 =H, CH3, or higher alkyl group.
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- Ring closure reactions of substituted 4-pentenyl-1-oxy radicals. The stereoselective synthesis of functionalized disubstituted tetrahydrofurans
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N-(Alkyloxy)pyridine-2(1H)-thiones 3 and benzenesulfenic acid O-esters 5 have been synthesized from substituted 4-pentenols 1 or the derived tosylates. Compounds 3 and 5 are efficient sources of free alkoxy radicals 6 which undergo synthetically useful fast ring closure reactions 6 → 8 [k(exo) = (2 ± 1) x 108 s-1 to (6 ± 2) x 109 s-1 (T = 30 ± 0.2°C)]. Tetrahydrofurfuryl radicals 8 can be trapped with, e.g., hydrogen or chlorine atom donors to afford either trans- or cis-disubstituted tetrahydrofurans 10 or 12 depending on the substitution pattern of the 4-pentenyloxy radical. Substituted tetrahydropyrans 11 or 13 are formed in the minor 6-endo-trig cyclization. According to the data of competition kinetics, the observed stereoselectivities in free alkoxy radical cyclizations arise from steric interactions between the substituents in the transition state of the ring closure reactions. Alkyl substituents cause small differences in the measured relative rate constants of 5-exo cyclizations which are reminiscent of the data obtained from the rearrangements of alkyl-substituted 5-hexenyl radicals. Likewise, a stereochemical model for oxygen radical cyclization is proposed where the pentenyloxy chain adopts a six-membered, chairlike transition state with the alkyl substituents preferentially situated in the pseudoequatorial positions leading to 2,5-trans-, 2,4-cis-, and 2,3-trans-substituted tetrahydrofurfuryl radicals 8 as the major intermediates.
- Hartung,Gallou
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p. 6706 - 6716
(2007/10/03)
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- Reaction of diethylaminosulfur trifluoride with diols
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Diethylaminosulfur trifluoride (DAST) reacts with dialcohols to give difluorides, sulfite esters or cyclic ethers depending on the number of carbons separating the two alcohol groups.Vicinal and 1,3-diols give large amounts of sulfite ester products while butane-1,4-diol gives almost exclusively the cyclic ether tetrahydrofuran.Terminal dialcohols longer than four carbons give primarily difluoride products.Semiempirical calculations indicate a preference for cyclic intermediates when four or less carbons separate the two alcohol moieties.These cyclic intermediates lead directly to the cyclic ethers and sulfite ester products.
- Shellhamer, Dale F.,Anstine, D. Timothy,Gallego, Kelly M.,Ganesh, Brian R.,Hanson, Aaron A.,et al.
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p. 861 - 866
(2007/10/02)
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