- Synthesis of biomass-derived methylcyclopentane as a gasoline additive via aldol condensation/hydrodeoxygenation of 2,5-hexanedione
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A novel approach to produce biomass-derived gasoline is the hydrolysis of 2,5-dimethylfuran (DMF) to produce 2,5-hexanedione followed by base-catalyzed intramolecular aldol condensation of this product to form 3-methylcyclopent-2-enone (MCP). By proper choice of catalysts and conditions, MCP yields of 98% can be achieved. We further show that hydrogenation of MCP over Pt/NbOPO4 gives methylcyclopentane with virtually quantitative yields. Methylcyclopentane is an attractive gasoline substitute for ethanol, since its octane number is similar to ethanol and its gravimetric energy density is 58% higher. This journal is
- Sacia, Eric R.,Deaner, Matthew H.,Louie, Ying Lin,Bell, Alexis T.
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- 1,2- versus 1,4-addition to α-donor-cyclopenten-1-ones; a comparison of calculated and experimental data
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A series of α-donor-cyclopenten-1-ones, 1 (α-donor: X = H, Cl, Br, OMe, pyrrolidin-1-yl, SPh and SePh) were treated with methyllithium, lithium dimethylcuprate and cyanomethyllithium in tetrahydrofuran at -78°C. The reactions between 1 and methyllithium gave 1,2-adducts in 28-75% yield. No trace of the corresponding 1,4-adduct was observed. By treatment of 1 with lithium dimethylcuprate only 1,4-addition was obtained in 51-76% yield, except for X = OMe or pyrrolidin-1-yl, which gave no reaction at all. In the reactions between 1 and cyanomethyllithium the 1,2-adducts were the main products (43-60%), but varying amounts of 1,4-adducts (8-30%) were also formed. The products formed have been fully characterized. Net atomic charges obtained by density functional theory (DFT) calculations of the lithiated cations of 1 with X = H, Cl, Br or OMe showed very small differences between the substituted and unsubstituted systems for all X, except for X = OMe. In this case the C2 position was positive rather than negative. The C3 position was found to be significantly more negative. The calculated relative energies of the methylated and cyanomethylated 1,2- and 1,4-adducts with X = H, Cl, Br and OMe indicated that the 1,4-adducts were thermodynamically favoured by 8 to 12 kcal mol-1 for all but one case. In the cyanomethylation of 1 with X = OMe the 1,2-adduct was predicted to be favoured by 12 kcal mol-1. Thus, the predominance of 1,2-attack in the reactions involving methyllithium and cyanomethyllithium cannot be explained by the relative thermodynamic stabilities of the products.
- Gautun, Hanna S. H.,Carlson, Rolf,Skancke, Per N.
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- Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
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Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
- Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
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- Deciphering Reactivity and Selectivity Patterns in Aliphatic C-H Bond Oxygenation of Cyclopentane and Cyclohexane Derivatives
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A kinetic, product, and computational study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes has been carried out. HAT rates, site-selectivities for C-H bond oxidation, and DFT computations provide quantitative information and theoretical models to explain the observed patterns. Cyclopentanes functionalize predominantly at C-1, and tertiary C-H bond activation barriers decrease on going from methyl- and tert-butylcyclopentane to phenylcyclopentane, in line with the computed C-H BDEs. With cyclohexanes, the relative importance of HAT from C-1 decreases on going from methyl- and phenylcyclohexane to ethyl-, isopropyl-, and tert-butylcyclohexane. Deactivation is also observed at C-2 with site-selectivity that progressively shifts to C-3 and C-4 with increasing substituent steric bulk. The site-selectivities observed in the corresponding oxidations promoted by ethyl(trifluoromethyl)dioxirane support this mechanistic picture. Comparison of these results with those obtained previously for C-H bond azidation and functionalizations promoted by the PINO radical of phenyl and tert-butylcyclohexane, together with new calculations, provides a mechanistic framework for understanding C-H bond functionalization of cycloalkanes. The nature of the HAT reagent, C-H bond strengths, and torsional effects are important determinants of site-selectivity, with the latter effects that play a major role in the reactions of oxygen-centered HAT reagents with monosubstituted cyclohexanes.
- Martin, Teo,Galeotti, Marco,Salamone, Michela,Liu, Fengjiao,Yu, Yanmin,Duan, Meng,Houk,Bietti, Massimo
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supporting information
p. 9925 - 9937
(2021/06/30)
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- Method for preparing cyclopentanone compound by aqueous phase hydrogenation rearrangement of furfural and derivative thereof
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The invention provides a method for preparing a cyclopentanone compound by aqueous phase hydrogenation rearrangement of furfural and a derivative thereof, and belongs to the field of catalytic conversion of biomass resources. Specifically, a supported Ni3P catalyst converts furfural and a derivative thereof into a cyclopentanone compound in an H2 atmosphere, wherein the supported Ni3P catalyst provided by the invention is prepared by a deposition-precipitation chemical plating method. According to the invention, the catalyst obtained by the method is high in dispersity and small in particle size, and has high furfural and derivative conversion rate and cyclopentanone compound selectivity in the reaction of preparing cyclopentanone and derivatives thereof by aqueous phase hydrogenation rearrangement of furfural and derivatives thereof; and the furfural conversion rate and the cyclopentanone selectivity respectively reach 89.1% and 81.3% after the reaction is carried out for 1 hour at the pressure of 4 MPa H2 and the temperature of 160 DEG C.
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Paragraph 0048-0052
(2021/01/20)
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- Efficient Palladium(0) supported on reduced graphene oxide for selective oxidation of olefins using graphene oxide as a ‘solid weak acid’
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Selective oxidation of olefin derivatives to ketones has made innovative development over palladium(0) supported on reduced graphene oxide. Compared to traditional Wacker oxidation, the novel method offers an economical and environment-friendly option by using graphene oxide (GO) as a ‘solid weak acid’ instead of classical homogeneous catalysts like H2SO4 and CF3COOH. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy images of Pd0/RGO showed that the nanoscaled Pd particles generated at the flake structure of reduced graphene oxide. Under optimized condition, up to 44 kinds of ketones with different structures can be prepared with excellent yields.
- Gao, Xi,Zhou, Jianhao,Peng, Xinhua
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- SYSTEMS AND METHODS FOR SYNTHESIS OF PHENOLICS AND KETONES
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Embodiments herein relate to apparatus and systems for phenolic and ketone synthesis and methods regarding the same. In an embodiment, a method of producing phenolics and ketones is included. The method can specifically include forming a reaction mixture comprising nanocrystalline cellulose (NCC) and water. The method can also include contacting the reaction mixture with a metal oxide catalyst at a temperature of 350 degrees Celsius or higher and a pressure of at least about 3200 psi to form a reaction product mixture. The reaction product mixture can include at least about 20 wt. % phenolics and at least about 10 wt. % ketones as a percentage of the total mass of nanocrystalline cellulose (NCC). Other embodiments are also included herein.
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Paragraph 0080-0088
(2018/11/21)
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- Effect of Cp*Iridium(III) Complex and acid co-catalyst on conversion of furfural compounds to cyclopentanones or straight chain ketones
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In this paper, Cp*Ir (III) Complex and acid co-catalyst system was developed. By using Cp*Ir and γ-Al2O3 (Lewis acid), 5-hydroxymethylfurfural (5-HMF) can be converted efficiently to 3-hydroxymethyl cyclopentanone (HCPN). Meanwhile, Cp*Ir and Br?nsted acid can promote conversion of 5-HMF to 1-Hydroxy-2,5-hexanedione (HHD). The effect of Lewis acid and Br?nsted acid on the hydrogenation of furan derivatives was studied. Mechanism of conversion of 5-HMF to HCPN was discussed in detail and mechanism proposed by our predecessors was revised. Instead of being an intermediate for the formation of HCPN, it is believed that, HHD is a product of another reaction pathway. HHD condensed via Aldol reaction to produce 3-methylcyclopenten-2-ol-1-one (MCP) instead of HCPN. Under the promotion of Lewis acid, 5-HMF firstly convert to the precursor of HHD. After that, the reaction is through 4 π-electrocyclic ring closure process and HCPN was formed ultimately. Furthermore, we found that our Cp*Ir and acid co-catalyst system is suitable for a variety of furfural compounds. By using Cp*Ir, Br?nsted acid can promote conversion of furfural compounds to straight chain ketones and Lewis acid can promote the rearrangement of furfural compounds to cyclopentanone derivatives.
- Xu, Yong-Jian,Shi, Jing,Wu, Wei-Peng,Zhu, Rui,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 266 - 273
(2017/07/13)
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- Ni-based catalysts derived from a metal-organic framework for selective oxidation of alkanes
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Ni nanoparticles embedded in nitrogen-doped carbon (Ni@C-N) materials were prepared by thermolysis of a Ni-containing metal-organic framework (Ni-MOF) under inert atmosphere. The as-synthesized Ni@C-N materials were characterized by powder X-ray diffraction, N2 adsorption-desorption analysis, scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and X-ray photoelectron spectroscopy. The MOF-derived Ni-based materials were then examined as heterogeneous catalysts for the oxidation of alkanes under mild reaction conditions. The Ni@C-N composites displayed high activity and selectivity toward the oxidation of a variety of saturated C-H bonds, affording the corresponding oxidation products in good-to-excellent yields. Furthermore, the catalysts could be recycled and reused for at least four times without any significant loss in activity and selectivity under the investigated conditions.
- Zhou, Ying,Long, Jilan,Li, Yingwei
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p. 955 - 962
(2016/07/06)
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- Towards quantitative and scalable transformation of furfural to cyclopentanone with supported gold catalysts
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Given the vital importance of furfural (FFA) upgrading towards a sustainable bio-based economy, an eco-friendly aqueous route to produce a sole valuable product from FFA is highly desirable. We herein describe an efficient approach to quantitatively convert FFA into cyclopentanone (CPO) in neat water, employing H2 as the clean reductant and supported gold nanoparticles as a simple yet versatile catalyst. The use of anatase TiO2 featuring only mild Lewis acidic sites as the underlying support is essential, not only for preventing undesirable side reactions, but also for attaining high CPO selectivity. The feasibility of using biogenic CPO and CO2 as benign carbon sources to synthesize the industrially important feedstock dimethyl adipate is also demonstrated.
- Zhang, Gao-Shuo,Zhu, Ming-Ming,Zhang, Qi,Liu, Yong-Mei,He, He-Yong,Cao, Yong
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p. 2155 - 2164
(2016/04/19)
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- Production of 2,5-hexanedione and 3-methyl-2-cyclopenten-1-one from 5-hydroxymethylfurfural
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A novel approach for the production of 2,5-hexanedione (HDN) and 3-methyl-2-cyclopenten-1-one (3-MCO) from 5-hydroxymethylfurfural (HMF) by water splitting with Zn is reported for the first time. The use of high temperature water (HTW) conditions is the key for the efficient conversion of HMF to HDN and 3-MCO. Parameters regarding the Zn amount, temperature and reaction time are optimized and HDN and 3-MCO are produced in 27.3% and 30.5% yields, respectively. The roles of HTW and ZnO obtained by oxidation of Zn in water for the conversion of HMF, together with intermediate structures, are discussed to understand the mechanism of the reaction.
- Ren, Dezhang,Song, Zhiyuan,Li, Lu,Liu, Yunjie,Jin, Fangming,Huo, Zhibao
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supporting information
p. 3075 - 3081
(2016/06/06)
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- Ruthenium-catalyzed conjugate hydrogenation of ?±,?2-enones by in situ generated dihydrogen from paraformaldehyde and water
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Notwithstanding that the highly selective hydrogenation of ?±,?2-enones to allylic alcohols can be realized by using Noyori's Ru bifunctional system, the selective reduction of the C=C bonds in ?±,?2-enones without touching the C=O bonds still lacks a general, simple, and efficient procedure. Ruthenium-catalyzed conjugate hydrogenation of various ?±,?2-enones to saturated ketones with high selectivity was investigated. The most important feature of this procedure was that hydrogen in situ generated from paraformaldehyde (or formalin) and water was employed as the reductant.
- Li, Wanfang,Wu, Xiao-Feng
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supporting information
p. 331 - 335
(2015/03/05)
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- The organic-synthetic potential of recombinant Ene reductases: Substrate-Scope Evaluation and Process Optimization
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In this study an evaluation of the synthetic potential of a broad range of recombinant ene reductases was performed. In detail, a library of 23 ene reductases was used to screen the C=C reduction of 21 activated alkenes from different compound classes as substrates. The chosen set of substrates comprises nitroalkenes with an aryl substituent at the β-position and a methyl substituent at the α- or β-position, α,β-unsaturated carboxylic acids and their esters with and without substituents at the β-position, a range of cyclic α,β-unsaturated ketones with different ring sizes and substitution patterns and one α,β-unsaturated boronic acid. After we obtained insight into the substrate scope, several biotransformations were prioritised and further investigated in a screening of 41 reaction parameters (which included chaotropic and kosmotropic salts, polyols, buffer solutions, amino acids and organic solvents) towards their impact on the activity and enantioselectivity of the applied ene reductases. Under the optimised conditions, selected reduction processes were performed on an increased lab scale (up to 30 mL) with up to 10% substrate concentration, which led in general to both high conversion and (if chiral products were formed) enantioselectivity. Comprehensive screening: A detailed screening of 23 recombinant ene reductases for the reduction of 21 activated alkenes is performed as well as a subsequent study of the influence of 41 reaction parameters towards the enzyme activity and selectivity of selected reactions. In addition, a range of biocatalytic reductions on an increased laboratory scale are performed with substrate concentrations between 5 and 100 gL-1. EWG=Electron-withdrawing group.
- Re?, Tina,Hummel, Werner,Hanlon, Steven P.,Iding, Hans,Gr?ger, Harald
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p. 1302 - 1311
(2015/04/27)
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- Copper nanoparticles on dichromium trioxide: A highly efficient catalyst from copper chromium hydrotalcite for oxidant-free dehydrogenation of alcohols
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Stable copper(0) nanoparticles supported on chromium (Cu(0)/Cr2O3) are prepared from the composite precursor copper chromium hydrotalcite. The resulting Cu(0)/Cr2O3 catalyst is first used in the selective dehydrogenation of alcohols to aldehydes. More impressively, these dehydrogenations are performed without oxidants and yields of products are high. The stability of Cu(0)/Cr2O3 is also assessed by studying its recoverability and reusability for up to five cycles.
- Zhu, Yaoqin,Shen, Mengnan,Xia, Yonggen,Lu, Ming
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p. 152 - 156
(2015/03/30)
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- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
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The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Pichia stipitis OYE 2.6 variants with improved catalytic efficiencies from site-saturation mutagenesis libraries
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An earlier directed evolution project using alkene reductase OYE 2.6 from Pichia stipitis yielded 13 active site variants with improved properties toward three homologous Baylis-Hillman adducts. Here, we probed the generality of these improvements by testing the wild-type and all 13 variants against a panel of 16 structurally-diverse electron-deficient alkenes. Several substrates were sterically demanding, and as hoped, creating additional active site volume yielded better conversions for these alkenes. The most impressive improvement was found for 2-butylidenecyclohexanone. The wild-type provided less than 20% conversion after 24 h; a triple mutant afforded more than 60% conversion in the same time period. Moreover, even wild-type OYE 2.6 can reduce cyclohexenones with very bulky 4-substituents efficiently.
- Patterson-Orazem, Athéna,Sullivan, Bradford,Stewart, Jon D.
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p. 5628 - 5632
(2015/01/09)
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- Graphene-supported Pd nanoparticles: Microwave-assisted synthesis and as microwave-active selective hydrogenation catalysts
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Facile synthesis of graphene-supported Pd nanoparticles (NPs) with an average size of 5 nm (Pd/G) was achieved by a microwave-assisted reduction approach; the obtained Pd/G can be very effectively coupled to the microwave field, making it a high-performance catalyst (with turnover frequency (TOF) of 158 465 h-1) for microwave-assisted selective hydrogenation of isophorone at low temperatures. The Royal Society of Chemistry 2013.
- Yang, Jing-He,Ma, Ding
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p. 10131 - 10134
(2013/09/02)
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- Surface species of supported ruthenium catalysts in selective hydrogenation of levulinic esters for bio-refinery application
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Several supported noble metal catalysts were screened for the hydrogenation of methyl levulinate to c-valerolactone (GVL). Among these catalysts 5 % Ru/C showed the highest conversion of 95 % of methyl levulinate with 91 % selectivity to GVL. A detailed characterization was carried out using TPR, XRD, XPS and BET techniques. XPS studies revealed that higher extent of Ru0 species in case of carbon supported Ru was responsible for its higher hydrogenation activity as compared to Ru on other supports. Effect of process parameters such as temperature, H2 pressure, catalyst and substrate concentration and metal loading on methyl LA conversion and selectivity to GVL also has been studied. 5 % Ru/C catalyst was found to be stable up to five reuses.
- Hengne,Biradar,Rode
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experimental part
p. 779 - 787
(2012/08/28)
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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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- Method for the Production of Optically Active Carbonyl
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The present invention relates to a process for preparing optically active carbonyl compounds by asymmetrically hydrogenating α,β-unsaturated carbonyl compounds in the presence of optically active transition metal catalysts which are soluble in the reaction mixture and have at least one carbon monoxide ligand. The present invention especially relates to a process for preparing optically active aldehydes or ketones, in particular citronellal, by asymmetrically hydrogenating the corresponding optically active α,β-unsaturated aldehydes or ketones.
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- pH-dependent catalytic activity and chemoselectivity in transfer hydrogenation catalyzed by iridium complex with 4,4′-dihydroxy-2,2′- bipyridine
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Transfer hydrogenation catalyzed by an iridium catalyst with 4,4′dihydroxy-2,2′-bipyridine (DHBP) in an aqueous formate solution exhibits highly pH-dependent catalytic activity and chemoselectivity. The substantial change in the activity is due to the electronic effect based on the acid-base equilibrium of the phenolic hydroxyl group of DHBP. Under basic conditions, high turnover frequency values of the DHBP complex, which can be more than 1000 times the value of the unsubstituted analogue, are obtained (up to 81000 h-1 at 80°C). In addition, the DHBP catalyst exhibits pH-dependent chemoselectivity for α,β-unsaturated carbonyl compounds. Selective reduction of the C=C bond of enone with high activity are observed under basic conditions. The ketone moieties can be reduced with satisfactory activity under acidic conditions. In particular, pH-selective chemoselectivity of the C=O versus C=C bond reduction was observed in the transfer hydrogenation of cinnamaldehyde.
- Himeda, Yuichiro,Onozawa-Komatsuzaki, Nobuko,Miyazawa, Satoru,Sugihara, Hideki,Hirose, Takuji,Kasuga, Kazuyuki
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scheme or table
p. 11076 - 11081
(2009/11/30)
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- Polymeric DABCO-bromine complex: a mild oxidant for the preparation of ketones and aldehydes
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A stable, shelf-ready polymeric oxidant was prepared from the addition of Br2 to DABCO in CCl4. This material was used to convert simple primary and secondary alcohols to the corresponding aldehydes and ketones in biphasic CH2Cl2/H2O.
- Struss, John A.,Barnhart, William D.,Velasco, Maria R.,Bronley-DeLancey, Apryl
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p. 6635 - 6636
(2007/10/03)
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- Ketonic decarboxylation catalysed by weak bases and its application to an optically pure substrate
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Ketonic decarboxylation is a very old reaction that transforms two carboxylic acids into a ketone or a dicarboxylic acid into a cyclic ketone, in particular adipic acid into cyclopentanone. Herein it is reported that catalytic amounts of weak bases such as sodium carbonate can carry out this reaction selectively. This is in accordance with a mechanism involving decarboxylation and nucleophilic attack at a second carboxyl group. The reaction can be employed in asymmetric syntheses since the stereogenic centres in the β-positions retain their stereochemistry. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Renz, Michael,Corma, Avelino
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p. 2036 - 2039
(2007/10/03)
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- Zwitterionic relatives to the classic [(P-P)Rh(solv)2]+ ions: Neutral catalysts active for H-E bond additions to olefins (E = C, Si, B)
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Formally zwitterionic bis(phosphanyl)-and bis(amino)borate rhodium(1) complexes (see picture) can catalytically mediate the hydrogenation, hydroacylation, hydroboration, and hydrosilation of double bonds. These neutral systems are shown to be highly active, even under conditions incompatible with their isostructural, but formally cationic, relatives.
- Betley, Theodore A.,Peters, Jonas C.
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p. 2385 - 2389
(2007/10/03)
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- Cobalt(II)-catalyzed oxidation of alcohols into carboxylic acids and ketones with hydrogen peroxide
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The oxidation of aliphatic and aromatic alcohols into the corresponding carboxylic acid analogues and ketones has been carried out using 30% H2O2 and cobalt(II) complex 1 in good to high yields. The reaction is safe, clean and functions in the absence of additives.
- Das, Subhabrata,Punniyamurthy
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p. 6033 - 6035
(2007/10/03)
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- Cyclic ketones, their preparation and their use in the synthesis of amino acids
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A method is provided for making an enantiomerically pure of the formula: in which R and R′ represent C1?C10 alkyl, C2?C10 alkenyl or C3?C10 cycloalkyl and the wedges signify (S)- or (R)-stereochemistry, the substituents in compound (II) being trans. Conjugate addition is carried out between an organometallic nucleophile that provides a group R as defined above and (R)-4-acetoxycyclopent-2-en-1-one, (S)-4-acetoxycyclopent-2-en-1-one or a similar compound in which acetoxy is replaced by another leaving group to give, e.g. in the case of the acetoxy compound, a trans 3,4-disubstituted addition product of formula III or IV; The acetyl group is eliminated from the addition product to give an (R)- or (S)-4-alkyl or 4-alkenyl cyclopent-2-en-1-one the compound of formula is then to be hydrogenated to give a cyclopentanone of formula (I) or conjugate addition of a second organometallic nucleophile that provides a group R′ as defined above to the compound of the above formula may be carried out to give a trans 3,4-disubstituted addition product of formula (II). One of the above compounds may be converted e.g. via an intermediate (XV)-(XVIII) (in which the substituents R and R′ and the wedges have the meanings indicated above) to a gabapentin analogue of one of the formulae shown below: in which the substituents R and R′ and the wedges also have the meanings indicated above.
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- Graphite-supported ketodecarboxylation of carboxylic diacids
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Thermal decarboxylative cyclization of several carboxylic diacids supported on graphite gave the corresponding five- and six-membered cycloalkanones in high yields. The process took advantage of the retention of diacid on graphite, even for high temperature experiments (450 °C), which avoid its vaporization. Moreover, the addition of catalyst is useless, the iron-containing inclusions present on graphite play this function. The reactions were also realized under microwave irradiation.
- Marquié,Laporterie,Dubac,Roques
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p. 493 - 496
(2007/10/03)
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- Iridium-catalyzed transfer hydrogenation of α,β-unsaturated and saturated carbonyl compounds with 2-propanol
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The selective transfer hydrogenation of α,β-unsaturated carbonyl compounds to saturated ones was achieved by the use of 2-propanol as a hydrogen donor under the influence of catalytic amounts of [Ir(cod)Cl]2, 1,3-bis(disphenylphosphino)propane (dppp), and Cs2CO3. Thus, a variety of conjugated enones were allowed to react with 2-propanol in the presence of the [Ir(cod)Cl]2/dppp/Cs2CO3 system to give the corresponding saturated carbonyl compounds in good to excellent yields without formation of allylic alcohols. Both dppp and Cs2CO3 were essential components to achieve the reduction satisfactorily. Additionally, the reduction of carbonyl compounds to alcohols was also promoted by the same catalytic system. When the reaction of a 1:1 mixture of a conjugated ketone and a saturated ketone with 2-propanol was carried out in the presence of [Ir(cod)Cl]2 combined with dppp and Cs2CO3, the reduction of the α,β-unsaturated ketone was found to take place in preference to that of the saturated ketone.
- Sakaguchi,Yamaga,Ishii
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p. 4710 - 4712
(2007/10/03)
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- Amidino derivatives useful as nitric oxide synthase inhibitors
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The current invention discloses useful pharmaceutical compositions containing amidino derivative useful as nitric oxide synthase inhibitors.
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- Amidino dervatives useful as nitric oxide synthase inhibitors
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The current invention discloses useful pharmaceutical compositions containing azepine derivatives useful as nitric oxide synthase inhibitors.
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- Radical addition to carbenoids. Chain reactions of α-diazo carbonyl compounds with triorganotin hydrides, tris(trimethylsilyl)silane and allyltributylstannane
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α-Diazo ketones RC(O)CH=N2 react with tributyltin hydride at 60°C in benzene to give the corresponding α-stannyl ketones RC(O)CH2SnBu3, which exist in equilibrium with the stannyl enol ether tautomers R(Bu3SnO)C=CH2. The reactions are initiated by di-tert-butyl hyponitrite and follow a free-radical chain mechanism. Triphenyltin hydride and tris(trimethylsilyl)silane [(TMS)3SiH] react similarly, the latter to yield the α-silyl ketone RC(O)CH2Si(TMS)3 which does not isomerise to the more stable silyl enol ether R[(TMS)3SiO]C=CH2 under the reaction conditions. This result indicates that TMS3Si. reacts at the α-carbon atom of the α-diazo ketone to give R(CO)CHSiTMS3, probably via an initial diazenyl radical adduct; triorganotin radicals are assumed to react in the same way. When the group R in the α-diazo ketone is but-3-enyl, the intermediate α-metalloalkyl radical undergoes 5-exo-cyclisation. Allyltributylstannane reacts with α-diazo ketones and with ethyl α-diazoacetate in refluxing benzene, in the presence of 2,2′-azo(2-methylpropionitrile) as initiator, to give butenyl ketones RC(O)CH2CH2CH=CH2 and ethyl pent-4-enoate, respectively, after a hydrolytic work-up.
- Dang, Hai-Shan,Roberts, Brian P.
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p. 769 - 775
(2007/10/03)
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- Cu/SiO2: An improved catalyst for the chemoselective hydrogenation of α,β-unsaturated ketones
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Cu/SiO2 can be conveniently used for the quantitative hydrogenation of conjugated enones to saturated ketones, also when another olefinic bond is present in the molecule, under very mild conditions. Molecular H2 or 2-propanol can be used as hydrogen source.
- Ravasio, Nicoletta,Antenori, Marisa,Gargano, Michele,Mastrorilli, Piero
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p. 3529 - 3532
(2007/10/03)
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- Aluminium trichloride hexahydrate-zinc-THF-A new system for the reduction of carbon-carbon double bonds
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Aluminium trichloride hexahydrate-Zn-THF system selectivity reduces α,β-unsatureted carbonyl and enedicarbonyl compounds to the corresponding dihydro compounds in good yields.
- Konwar, Dilip,Dutta, Dilip Kumar,Sandhu, Jagir Singh
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p. 725 - 727
(2007/10/03)
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- Enantioselective conjugate addition to cyclic enones with scalemic lithium organo(amido)cuprates, part IV. Relationship between ligand structure and enantioselectivity
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Scalemic lithium amides derived from primary and secondary amines react with organocopper compounds in ether or dimethyl sulfide to form lithium organo(amido)cuprates capable of enantioselective conjugate addition to 2-cycloalkenones. The most successful heterocuprate, in which the chiral ligand is (S)-N-methyl-1-phenyl-2-(1-piperidinyl)ethanamine, (S)-MAPP, 13, reacts with cyclic enones to form products with up to 97% ee. Nonlinear asymmetric induction was observed with the cuprate formed from ligand 13.
- Rossiter, Bryant E.,Eguchi, Masakatsu,Miao, Guobin,Swingle, Nicole M.,Hernandez, Amelia E.,Vickers, Denise,Fluckiger, Ezdan,Greg Patterson,Vasavi Reddy
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p. 965 - 986
(2007/10/02)
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- MILD REDUCTION OF α,β-UNSATURATED KETONES AND ALDEHYDES WITH AN OXYGEN-ACTIVATED PALLADIUM CATALYST
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Reaction of the binuclear palladium complex, 2, where R=t-Bu, with oxygen gives a very efficient catalyst for the hydrogenation of α,β-unsaturated carbonyls.
- Sommovigo, Milena,Alper, Howard
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- On the conjugate addition of tetraorganothallium ate complexes
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Tetraorganothallium ate complexes have been prepared and reacted with enones to afford either the [1,2] or [1,4] addition product. Mixed ate complexes display high levels of chemoselectivity in the transfer of one of their ligands.
- Marko,Rebiere
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p. 1763 - 1766
(2007/10/02)
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- Asymmetrische Katalysen, 58. Mitt.: Enantioselektive S-H- und C-H-Insertionen mit optisch aktiven Rh(II)- und Cu(II)-Katalysatoren
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The substrates for the S-H insertion reaction were azibutanone 2 and thiophenol 3.Methyl 2-diazo-3-oxo-heptane-caboxylate 26 was used as the substrate in an intramolecular C-H insertion.Both reactions were carried out enantioselectively in the presence of optically active rhodium(II) and copper(II) catalysts.For the S-H insertion optical inductions up to 13.8percentee and for the C-H insertion up to 14percentee were achieved.
- Brunner, Henri,Wutz, Konrad,Doyle, Michael
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p. 755 - 764
(2007/10/02)
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- ORGANOCOPPER REAGENTS IN DIMETHYL SULFIDE
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Organocopper(I) reagents, RCu, are both more stable and more reactive when prepared in dimethyl sulfide instead of ether or tetrahydrofuran.A wide range of Li reagents has been investigated with good results, as has a selection of Grignard reagents.Excellent yields of products are observed with typical substrates as α,β-unsaturated ketones and acid chlorides.
- Bertz, Steven H.,Dabbagh, Gary
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p. 425 - 434
(2007/10/02)
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- Process for producing an oxygen-containing organic compound from olefins
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A process for producing an oxygen-containing organic compound by oxidizing olefins under milder conditions is provided, which process comprises oxidizing an olefin activated by its complex formation, in the presence of a platinum group metal complex capable of forming an olefin complex through coordination of the platinum group metal with said olefin, and also in the presence of water, and further oxidizing and regenerating the resulting reduced platinum group metal complex with oxygen coordinated with a transition metal and activated thereby.
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- FUNCTIONALISATION OF SATURATED HYDROCARBONS. Part X. A COMPARATIVE STUDY OF CHEMICAL AND ELECTROCHEMICAL PROCESSES (GIF AND GIF-ORSAY SYSTEMS) IN PYRIDINE, IN ACETONE AND IN PYRIDINE-CO-SOLVENT MIXTURES
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Six saturated hydrocarbons (cyclohexane, 3-ethylpentane, methylcyclopentane, cis- and trans-decalin and adamantane) were oxidised by the Gif system (iron catalyst, oxygen, zinc, carboxylic acid) and its electrochemical equivalent (Gif-Orsay system).Results obtained using various solvents (pyridine, acetone, pyridine-acetone mixtures) were similar for both systems.Total or partial replacement of pyridine with acetone affects the selectivity for secondary positions and lowers the ketone/secondary alcohol ratio.The formation of the same ratio of cis- and trans-decal-9-ol from both cis- and trans-decalin clearly demonstrates that tertiary alcohols result from a mechanism essentially radical in nature.
- Belavoine, Gilbert,Barton, Derek H. R.,Boivin, Jean,Gref, Aurore,Coupanec, Pascale Le,et al.
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p. 1091 - 1106
(2007/10/02)
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- ULTRASONICALLY IMPROVED REDUCTIVE PROPERTIES OF AN AQUEOUS Zn-NiCl2 SYSTEM - 1 SELECTIVE REDUCTION OF α,β-UNSATURATED CARBONYL COMPOUNDS
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Conjugate addition of several compounds is obtained with good to excellent yield in an aqueous medium using a reagent constituted by zinc dust and nickel chloride(9-1).Ultrasounds are shown to improve the yields and reaction rates.
- Petrier, Christian,Luche, Jean-Louis
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p. 2347 - 2350
(2007/10/02)
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- Conjugate Addition Reactions of α,β-Unsaturated Ketones with Higher Order, Mixed Organocuprate Reagents, R2Cu(CN)Li2
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Conjugate reactions of mixed cuprates R2Cu(CN)Li2 with α,β-unsaturated ketones are reported.These reagents, in most cases, react extremely rapidly affording the corresponding alkylated ketones in high yields.Attempts at trapping the intermediate enolates appeared to be successful using MeI as electrophile; however, the method is not general and was, therefore, not pursued.The effects of solvent and ligand composition on R2Cu(CN)Li2 as well as on the more highly mixed species RTRRCu(CN)Li2 have been examined.The selectivity of ligand transfer in these latter,second generation organocuprates is also discussed.
- Lipshutz, Bruce H.,Wilhelm, Robert S.,Kozlowski, Joseph A.
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p. 3938 - 3942
(2007/10/02)
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- Biphasic hydrogenation of olefins, dienes, and α,β-unsaturated carbonyl compounds catalyzed by the dimer of chloro(1,5-hexadiene)rhodium
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Olefins, dienes, and trienes can be hydrogenated in an aqueous-organic two-phase medium using the dimer of chloro(1,5-hexadiene)rhodium as the catalyst.Selective reduction of the double bond of α,β-unsaturated carbonyls occurs in high yields.These reactions occur at room temperatures and atmospheric pressure, and are simple to work up.
- Januszkiewicz, Krzysztof R.,Alper, Howard
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p. 1031 - 1033
(2007/10/02)
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- ORGANOCOPPER CONJUGATE ADDITION REVISITED
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An efficient organocopper conjugate addition based on the use of equimolar amounts of an enone and an entering group is described.
- Suzuki, M.,Suzuki, T.,Kawagishi, T.,Noyori, R.
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p. 1247 - 1250
(2007/10/02)
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- Sequential Catalytic Condensation-Hydrogenation of Ketones
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Aldol condensation and hydrogenation of the condensation product have been carried out simultaneously by using an immobilized acid catalyst (Nafion-H or Amberlite IR-120) and Pd/C under hydrogen.Acetone was converted to 4-methyl-2-pentanone in a one-pot multistep process at 60-140 deg C and 20-300 psi of hydrogen.The yields of 4-methyl-2-pentanone were higher than the equilibrium-limited yields of mesityl oxide obtained in the absence of the hydrogenation catalyst, demonstrating that the equilibrium to mesityl oxide was shifted by mesityl oxide hydrogenation to 4-methyl-2-pentanone. 2-Propanol was the major byproduct because acetone hydrogenation was competitive with condensation.High-boiling products, found in aldol condensations, were not formed in the condensation-hydrogenation process.Use of RhCl(PPh3)3 or its polymer-bound analogue as the hydrogenation catalyst reduced the amount of acetone hydrogenation but slowed the condensation-hydrogenation reactions.The crossed aldol condensation-hydrogenation of benzaldehyde and acetone gave 4-phenyl-2-butanone with Nafion-H and Pd/C.The major side reaction was the competitive hydrogenation of benzaldehyde to toluene.The intramolecular condensation of 2,5-hexanedione gave mainly 2,5-dimethylfuran while the one-pot condensation-hydrogenation reaction gave 2,5-dimethyltetrahydrofuran.
- Pittman, Charles U.,Liang, Yeon F.
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p. 5048 - 5052
(2007/10/02)
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