- Application of Microwave Heating Techniques for Dry Organic Reactions
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A commercially available microwave oven operating at 2450 MHz has been used for activation of organic compounds adsorbed on inorganic solids.
- Alloum, Abdelkrim Ben,Labiad, Bouchta,Villemin, Didier
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- Photocatalytic Reaction of Ethanol over Titanium Diselenide
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A suspension of TiSe2 in ethanol was illuminated with ultraviolet light in an atmosphere of Ar, air, or O2 at 298 K.The main products were acetaldehyde, acetaldehyde diethyl acetal (acetal), acetic acid, water, hydrogen, ethylene, methane, and carbon dioxide.Each yield of the products under air or O2 was higher than under Ar, except for that of hydrogen and ethylene.Platinum under an O2 atmosphere exerted its effect for producing CH3COOH, acetal, CO2, CH3CHO, CH4, and H2O, while under Ar it contributed to generating CO2, CH4, and H2.No effect of Pt was observed for generating C2H4 under either an atmosphere of Ar or O2.
- Iseda, Kozo,Osaki, Toshihiko,Taoda, Hiroshi,Yamakita, Hiromi
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- Electrochemically Generated cis-Carboxylato-Coordinated Iron(IV) Oxo Acid-Base Congeners as Promiscuous Oxidants of Water Pollutants
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The nonheme iron(IV) oxo complex [FeIV(O)(tpenaH)]2+ and its conjugate base [FeIV(O)(tpena)]+ [tpena- = N,N,N′-tris(2-pyridylmethyl)ethylenediamine-N′-acetate] have been prepared electrochemically in water by bulk electrolysis of solutions prepared from [FeIII2(μ-O)(tpenaH)2](ClO4)4 at potentials over 1.3 V (vs NHE) using inexpensive and commercially available carbon-based electrodes. Once generated, these iron(IV) oxo complexes persist at room temperature for minutes to half an hour over a wide range of pH values. They are capable of rapidly decomposing aliphatic and aromatic alcohols, alkanes, formic acid, phenols, and the xanthene dye rhodamine B. The oxidation of formic acid to carbon dioxide demonstrates the capacity for total mineralization of organic compounds. A radical hydrogen-atom-abstraction mechanism is proposed with a reactivity profile for the series that is reminiscent of oxidations by the hydroxyl radical. Facile regeneration of [FeIV(O)(tpenaH)]2+/ [FeIV(O)(tpena)]+ and catalytic turnover in the oxidation of cyclohexanol under continuous electrolysis demonstrates the potential of the application of [FeIII(tpena)]2+ as an electrocatalyst. The promiscuity of the electrochemically generated iron(IV) oxo complexes, in terms of the broad range of substrates examined, represents an important step toward the goal of cost-effective electrocatalytic water purification.
- De Sousa, David P.,Miller, Christopher J.,Chang, Yingyue,Waite, T. David,McKenzie, Christine J.
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- Visible-Light Direct Conversion of Ethanol to 1,1-Diethoxyethane and Hydrogen over a Non-Precious Metal Photocatalyst
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Converting renewable biomass and their derivatives into chemicals and fuels has received much attention to reduce the dependence on fossil resources. Photocatalytic ethanol dehydrogenation–acetalization to prepare value-added 1,1-diethoxyethane and H2 was achieved over non-precious metal CdS/Ni-MoS2 catalyst under visible light. The system displays an excellent production rate and high selectivity of 1,1-diethoxyethane, 52.1 mmol g?1 h?1 and 99.2 %, respectively. In-situ electron spin resonance, photoluminescence spectroscopy and transient photocurrent responses were conducted to investigate the mechanism. This study provides a promising strategy for a green application of bioethanol.
- Chao, Yuguang,Zhang, Wenqin,Wu, Xuemei,Gong, Nana,Bi, Zhihong,Li, Yunqin,Zheng, Jianfeng,Zhu, Zhenping,Tan, Yisheng
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- A site-holding effect of TiO2 surface hydroxyl in the photocatalytic direct synthesis of 1,1-diethoxyethane from ethanol
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To understand the mechanism of the photocatalytic direct synthesis of 1,1-diethoxyethane (DEE) from ethanol is vital for enhancing the reaction efficiency. Based on photocatalytic data of different phase TiO2 and F-TiO2 catalysts, radical trapping data, and GC-MS data, we proposed a photocatalytic mechanism for the preparation of both DEE in neat ethanol and 2,3-butanediol (2,3-BD) in ethanol-H2O using photocatalytic methods. In neat ethanol, hydroxyl isn’t involved in the catalytic cyclic process but hydroxyl has an indirect site-holding effect, thus leading to more hydroxyl groups with higher activity. In ethanol-H2O, although the strong oxidant ?OH radical is involved, fewer OH groups lead to higher selectivity of 2,3-BD. The interaction of the reactant/solvent with the surface group of the catalyst is important in the activity and selectivity of photocatalytic reactions. This finding gives fundamental insight into the role of TiO2 surface hydroxyl in the photocatalytic dehydrogenation process of alcohols and opens a promising path to obtaining both high selectivity and high conversion in TiO2-based photocatalytic activity.
- Zhang, Hongxia,Zhang, Wenqin,Zhao, Min,Yang, Pengju,Zhu, Zhenping
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- Photocatalytic direct conversion of ethanol to 1,1- diethoxyethane over noble-metal-loaded TiO2 nanotubes and nanorods
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As one of the most important biomass platform molecules, ethanol needs to have its product chain chemically extended to meet future demands in renewable fuels and chemicals. Additionally, chemical conversion of ethanol under mild and green conditions is still a major challenge. In this work, ethanol is directly converted into 1,1-diethoxyethane (DEE) and H2 under mild photocatalytic conditions over platinum-loaded TiO2 nanotubes and nanorods. The reaction follows a tandem dehydrogenation-acetalization mechanism, in which ethanol is first dehydrogenated into acetaldehyde and H+ ion by photogenerated holes, and then acetalization between acetaldehyde and ethanol proceeds through promotion by H+ ions formed in real time. Excess H+ ions are simultaneously reduced into H2 by photogenerated electrons. This photocatalytic process has a very high reaction rate over nanosized tubular and rod-like TiO2 photocatalysts, reaching 157.7 mmol g-1 h-1 in relatively low photocatalyst feeding. More importantly, the reaction is highly selective, with a nearly stoichiometric conversion of reacted ethanol into DEE. This photocatalytic dehydrogenation C-O coupling of ethanol is a new green approach to the direct efficient conversion of ethanol into DEE and provides a promising channel for sustainable bioethanol applications.
- Zhang, Hongxia,Wu, Yupeng,Li, Li,Zhu, Zhenping
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- TiO2-photocatalytic acceptorless dehydrogenation coupling of primary alkyl alcohols into acetals
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Primary alkyl alcohols can be directly converted into acetals and H 2via TiO2-photocatalytic dehydrogenation coupling at room temperature, with no need for any hydrogen acceptors. The reaction follows a tandem process integrating photocatalytic alcohol dehydrogenation and H +-catalytic acetalation, in which the H+ ion catalysts are provided by the alcohol dehydrogenation in real time. This approach exhibits a very high reaction rate and product selectivity, and represents a novel green process for the conversion of primary alkyl alcohols, especially for bio-renewable ethanol and 1-butanol. the Partner Organisations 2014.
- Zhang, Hongxia,Zhu, Zhenping,Wu, Yupeng,Zhao, Tianjian,Li, Li
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- One Nanometer PtIr Nanowires as High-Efficiency Bifunctional Catalysts for Electrosynthesis of Ethanol into High Value-Added Multicarbon Compound Coupled with Hydrogen Production
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The electrosynthesis of high-value-added multicarbon compounds coupled with hydrogen production is an efficient way to achieve carbon neutrality; however, the lack of effective bifunctional catalysts in electrosynthesis largely hinders its development. Herein, we report the first example on the highly efficient electrosynthesis of high-value-added 1,1-diethoxyethane (DEE) at the anode and high-purity hydrogen at the cathode using 1 nm PtIr nanowires (NWs) as the bifunctional catalysts. We demonstrate that the cell using 1 nm PtIr nanowires as the bifunctional catalysts can achieve a reported lowest voltage of 0.61 V to reach the current density of 10 mA cm-2, much lower than those of the Pt NWs (0.85 V) and commercial Pt/C (0.86 V), and also can have the highest Faraday efficiencies of 85% for DEE production and 94.0% for hydrogen evolution in all the reported electrosynthesis catalysts. The in situ infrared spectroscopy study reveals that PtIr NWs can facilitate the activation of O-H and C-H bonds in ethanol, which is important for the formation of acetaldehyde intermediate, and finally DEE. In addition, the cell using PtIr NWs as bifunctional catalysts exhibits excellent stability by showing almost no obvious decrease in the Faraday efficiency of the DEE production.
- Chao, Yuguang,Gu, Lin,Guo, Shaojun,Li, Hongbo,Li, Menggang,Lu, Shiyu,Lv, Fan,Tao, Lu,Yin, Kun,Zhang, Qinghua,Zhang, Weiyu
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- Upgrading of Ethanol to 1,1-Diethoxyethane by Proton-Exchange Membrane Electrolysis
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The direct acetalization of ethanol is a significant challenge for upgrading bioethanol to value-added chemicals. In this study, 1,1-diethoxyethane (DEE) is selectively synthesized by the electrolysis of ethanol using a proton-exchange membrane (PEM) reactor. In the PEM reactor, a Pt/C catalyst promoted the electro-oxidation of ethanol to acetaldehyde. The Nafion membrane used as the PEM served as a solid acid catalyst for the acetalization of ethanol and electrochemically formed acetaldehyde. DEE was obtained at high faradaic efficiency (78 %) through sequential electrochemical and nonelectrochemical reactions. The DEE formation rate through PEM electrolysis was higher than that of reported systems. At the cathode, protons extracted from ethanol were reduced to H2. The electrochemical approach can be utilized as a sustainable process for upgrading bioethanol to chemicals because it can use renewable electricity and does not require chemical reagents (e. g., oxidants and electrolytes).
- Kawaguchi, Daisuke,Ogihara, Hitoshi,Kurokawa, Hideki
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- A Strategy for the Simultaneous Synthesis of Methallyl Alcohol and Diethyl Acetal with Sn-Β
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A new strategy was developed to simultaneously produce two important chemicals, namely, methallyl alcohol (Mol) and diethyl acetal (Dal) from methacrolein in ethanol solvent at low temperature with the use of Beta zeolites modified by tin (Sn-β catalysts). All the Sn-β catalysts were prepared by the solid-state ion-exchange method, wherein the calcination step was conducted under different gas atmospheres. The catalyst precalcined in Ar (Sn-β-Ar) had a reduced number of extra-framework Sn species and enabled more Sn species to be exchanged into the framework as isolated tetrahedral SnIV, enhancing the catalytic activity of the Meerwein–Ponndorf–Verley (MPV) reaction. The sodium-exchanged Sn-β-Ar, with a reduced number of weak Br?nsted acid sites, led to an even better selectivity for Mol, owing to the restriction of the side reactions such as acetalization, addition, and etherification. Under optimized catalyst and reaction conditions, the yield of Mol and Dal reached approximately 90 % and 96 %, respectively. The possible reaction pathways, along with a complex network of side products, was proposed after a detailed investigation through the use of different substrates as reactants. The fine-tuning of Sn-β catalysts through different treatments discussed in this work is of great significance toward the understanding and manipulation of complex reactions between α,β-unsaturated aldehydes and primary alcohols.
- Hu, Wenda,Wan, Yan,Zhu, Lili,Cheng, Xiaojie,Wan, Shaolong,Lin, Jingdong,Wang, Yong
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- Photocatalytic decarboxylation of lactic acid by Pt/TiO2
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A photocatalytic route for the conversion of lactic acid to acetaldehyde in water is demonstrated. Direct UV photolysis of lactic acid yields CO2 and ethanol via a radical mechanism. Pt/TiO2 considerably increases the rate of lactic acid decarboxylation with acetaldehyde, H2 and CO2 as the main products. A concerted photodecarboxylation/dehydrogenation mechanism is proposed.
- Liu, Kaituo,Litke, Anton,Su, Yaqiong,Van Campenhout, Bart G.,Pidko, Evgeny A.,Hensen, Emiel J. M.
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- The role of oxide location in HMF etherification with ethanol over sulfated ZrO2 supported on SBA-15
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The etherification of 5-hydroxymethyl-2-furfural (HMF) over ZrO2 and sulfated ZrO2-SBA-15 was chosen as a case study to analyze (i) the quantitative relationship between the concentration of Lewis and Bronsted acid sites and the catalytic behavior in the above reaction, which is also of industrial relevance for the production of biodiesel additives, and (ii) how the location of zirconia nanoparticles inside or outside the mesoporous channels of SBA-15 could significantly influence the specific reactivity in this reaction, both before and after sulfation. Depending on the loading of zirconia (about 10 or 35 wt%), the characterization data by different techniques (TEM, XRD, BET, Dr-UV-vis, and XPS) agree in indicating that zirconia is located predominantly outside the mesoporous channels as small zirconia nanoparticles for the lower loading, and predominantly inside the mesoporous channels for the higher loading. The concentration of medium-strong Lewis and Bronsted acid sites were determined by pyridine chemisorption monitored by IR spectroscopy. While the concentration of Bronsted acid sites (formed after sulfation) is linearly dependent on the amount of zirconia in SBA-15, a marked deviation is observed for Lewis acid sites. The same conclusion was derived from analysis of the dependence of the catalytic activity in Lewis- or Bronsted-acid-site-promoted reactions. The analysis of these results indicated that the characteristics of the zirconia nanoparticles deposited outside or inside the mesoporous silica channels differ in terms of acid features and in turn of catalytic reactivity.
- Barbera,Lanzafame,Pistone,Millesi,Malandrino,Gulino,Perathoner,Centi
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- One-step continuous process for the production of 1-butanol and 1-hexanol by catalytic conversion of bio-ethanol at its sub-/supercritical state
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A one-step, easy to scale-up, continuous process was developed to catalytically convert bio-ethanol into 1-butanol and 1-hexanol as chemicals or fuels, as well as some other compounds that are also useful as biogasoline. The process is novel as it employs ethanol at its sub- and supercritical states. The reactions were performed in a continuous-flow fixed-bed tubular reactor with γ-alumina supported Ni catalysts at 135-300 °C at a weight hourly space velocity of 6.4-15.6 h-1 using neat ethanol. The process at 250 °C and 176 bar with an 8% Ni/γ-alumina catalyst led to ethanol conversion of 35%, with the highest selectivity of approximately 62% and 21% towards 1-butanol and 1-hexanol, respectively. In addition to 1-butanol and 1-hexanol, other minor biogasoline components such as butanal, and 2-pentanone, etc. were also synthesized from this process. The catalyst was found active for 18 h on stream in this study, and the regenerated catalysts retained their activities for the reactions. The Royal Society of Chemistry 2013.
- Ghaziaskar, Hassan S.,Xu, Chunbao Charles
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- Liquid-phase hydrodechlorination of CCl4 with co-production of diethylcarbonate and acetal
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Liquid-phase hydrodechlorination of CCl4 over supported Pd or Pt catalysts in the presence of C2H5OH gave not only the selective synthesis of CHCl3, but also conversion of C2H5OH to diethyl
- Bae, Jong Wook,Lee, Jae Sung,Lee, Kyung Hee,Jang, Eun Joo
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- (V)/Hydrotalcite, (V)/Al2O3, (V)/TiO2 and (V)/SBA-15 catalysts for the partial oxidation of ethanol to acetaldehyde
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Vanadium-based catalysts have been investigated in the partial oxidation of ethanol to acetaldehyde with the aim of understanding relationship between vanadium structure and acetaldehyde productivity. Hydrotalcite, Al2O3, TiO2 and SBA-15 with and without a 5% of vanadium content were prepared to study the oxidative dehydrogenation of ethanol. They were characterized by XRF, TPR (H2), NH3-TPD, CO2-TPD, RAMAN, UV-vis, Nitrogen physisorption, XRD and SEM. The most easily reducible catalysts (as determined by TPR) were the most active ones. In the low temperature region (150 °C), the most active catalyst was the V/TiO2 which presented stable activity in the production of acetaldehyde up to TOS = 200 h. On the contrary, in the high temperature region (250 °C), the most active catalyst was the V/Al2O3catalyst. The most promising result was obtained over V/TiO2 catalyst that afforded a total ethanol conversion of 60.4%wt. and a selectivity to acetaldehyde of 76.2%wt. at TOS = 164 h and T = 150 °C. Also, hydrotalcite was tested for the first time for this type of reaction providing a conversion lower than 7%wt. with a selectivity of 100%wt. to acetaldehyde at T = 150-225 °C.
- Hidalgo,Ti?ler,Kubi?ka,Raabova,Bulanek
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- P-Benzoquinone adsorption-separation, sensing and its photoinduced transformation within a robust Cd(II)-MOF in a SC-SC fashion
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p-Benzoquinone (Q) adsorption-separation, sensing and its photoinduced transformation within a robust Cd(ii)-MOF (1) is reported. All the adsorption, sensing and photochemical reactions are directly performed on the single-crystals of 1. This journal is
- Yang, Fan,Liu, Qi-Kui,Wu, Dan,Li, An-Yan,Dong, Yu-Bin
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- Efficient synthesis of 1,1-diethoxyethane via sequential ethanol reactions on silica-supported copper and H-Y zeolite catalysts
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1,1-Diethoxyethane (DEE) is an important chemical with versatile applications. Here, we report the efficient synthesis of DEE via two-sequential reactions of ethanol including the selective dehydrogenation of ethanol to acetaldehyde and the subsequent acetalization of acetaldehyde with ethanol to DEE. The ethanol dehydrogenation was examined on Cu catalysts supported on SiO2, Al2O3, ZrO2 and TiO 2 supports with similar Cu dispersions, and Cu/SiO2 was more selective to acetaldehyde with 99.0% selectivity at 493 K, due to the inert surface of SiO2, compared to the other three oxide supports with stronger acidity and basicity facilitating the side reactions of acetaldehyde. For the equilibrium-limited acetalization reaction, comparison of representative solid acids (e.g. SO42-/ZrO2, Amberlyst 15, H-Y zeolite and AlCl3/SiO2) showed that while they offered nearly 100% DEE selectivities, the Br?nsted acid sites were more active than the Lewis acid sites. This was confirmed by the higher activities (normalized per acid site) for the H-Y zeolites with higher factions of the Br?nsted acid sites obtained by calcination at lower temperatures in the range 773-1073 K. Combination of the ethanol dehydrogenation on Cu/SiO 2 at 493 K and the acetalization reaction on H-Y (calcined at 773 K) at 293 K in the two-sequential flow microreactors led to the steady conversion of ethanol to DEE in a yield of as high as 35.0%. This yield could be further improved, for example, to 70.5%, the highest yield from ethanol reported to date, after removal of water in the acetalization reactor by 3A zeolite. Such two-sequential reactor configuration also applied to the efficient synthesis of other important acetals, and as an example, dimethoxymethane was synthesized directly from methanol in a yield of 84.1% on iron molybdate and H-ZSM-5 catalysts.
- He, Xiaohui,Liu, Haichao
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- Photocatalytic H2 production by ethanol photodehydrogenation: Effect of anatase/brookite nanocomposites composition
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In view of the sustainable H2 production, development of more efficient catalysts for photocatalytic reforming of oxygenated compounds is required. In this study, we report the preparation of TiO2 nanocomposite with anatase/brookite
- Romero Oca?a, Ismael,Beltram, Alessandro,Delgado Jaén, Juan Josè,Adami, Gianpiero,Montini, Tiziano,Fornasiero, Paolo
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- Chemical interconversions in the system Tp Zn/CO2/alcohol [Tp = substituted tris(pyrazolyl)borate]
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The zinc hydroxide complexes Tp*Zn-OH with TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)borate and TptBu,Me = tris(3-tert-butyl-5-methylpyrazolyl)borate can be converted to the alkyl carbonate complexes Tp*Zn-OCOOR by reaction with dialkyl dicarbonates or with alcohol and CO2. An alternative formation reaction is the treatment of the pyrazolyl borate with zinc perchlorate and potassium carbonate in alcohol. The interconversion between TpCum,MeZn-OH and TpCum.MeZn_OCOoMe in methanol-containing solution can be repeatedly performed in both directions by bubbling either CO2 or N2 through the solution. The alkyl carbonate complexes show a variable sensitivity towards hydrolytic destruction with reformation of the hydroxide complexes. The complexes TptBu,MeZn-OCOOR (R = Me, Et) release CO2 under high vacuum to form the alkoxide complexes TptBU,Me-Zn-OR, which could not be obtained pure due to their extreme water sensitivity. Indirect evidence for their existence is also obtained by the reaction between TpCum,MeZnOCOOMe and methyl iodide, forming TpCum,MeZn-I and dimethyl ether. The zinc hydroxide complexes catalyse the formation of diethyl carbonate from ethanol and CO2. VCEI Verlagsgcsellschaft mbH.
- Ruf, Michael,Schell, Friedrich Alexander,Walz, Rainer,Vahrenkamp, Heinrich
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- Making H2 from light and biomass-derived alcohols: The outstanding activity of newly designed hierarchical MWCNT/Pd@TiO2 hybrid catalysts
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Hydrogen evolution is among the most investigated catalytic processes given the importance of H2 from an industrial and an energy perspective. Achieving H2 production through green routes, such as water splitting or more realistically photoreforming of alcohols, is particularly desirable. In this work, we achieve a remarkable H2 productivity through photoreforming of either ethanol or glycerol as a sacrificial electron donor by employing a hybrid nanocatalyst where the properties of multi-walled carbon nanotubes (MWCNTs), Pd nanoparticles and crystalline TiO2 are optimally merged through appropriate engineering of the three components and an optimised synthetic protocol. Catalysts were very active both under UV (highest activity 25 mmol g-1 h-1) and simulated solar light (1.5 mmol h-1 g-1), as well as very stable. Critical to such high performance is the intimate contact of the three phases, each fulfilling a specific task synergistically with the other components.
- Beltram,Melchionna,Montini,Nasi,Fornasiero,Prato
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- Catalysis of the photodecomposition of carbon tetrachloride in ethanol by an Amberlite anion exchange resin
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The chloride form of the polystyrene-divinylbenzene anion exchange resin Amberlite IRA-900 was found to catalyze the photodecomposition of carbon tetrachloride in ethanol at wavelengths above 350 nm. With sulfate, bromide, and perchlorate as counterions, the resin was inactive. The major products are acetaldehyde, phosgene, chloroform, and hydrogen chloride. The photoreaction is much slower under 1.0 atm O2 than under air, while in deoxygenated solutions it is also much slower and produces no phosgene. Much of the observed behavior can be explained by a model in which the poly(styrene-co- divinylbenzene) matrix absorbs light and transfers energy to CCl4, which undergoes photodissociation, assisted by a chloride ion to stabilize the chlorine atom as Cl2-. Two major reaction channels for the trichloromethyl radicals produced by photodissociation are proposed, one in which CCl3 abstracts hydrogen from ethanol and the other involving addition of O2 to form trichloromethylperoxy radicals.
- Hoggard, Patrick E.,Maldotti, Andrea
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- Etherification of 5-hydroxymethyl-2-furfural (HMF) with ethanol to biodiesel components using mesoporous solid acidic catalysts
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The etherification of 5-hydroxymethyl-2-furfural (HMF) with ethanol is studied over a series of mesoporous silica catalysts (Al-MCM-41 materials with different Si/Al ratio, and zirconia or sulfated zirconia supported over SBA-15) and compared with the behavior of H2SO4 and Amberlyst15. The observed reaction products were 5-(ethoxymethyl)furan-2- carbaldehyde (EMF), 1,1-dietoxy ethane (DE) and ethyl 4-oxopentanoate (EOP). The selectivity to EMF and EOP is closely related to the presence of Lewis and/or Br?nsted acidity on the catalyst, while the formation of DE is probably related to defect sites. The latter, being less reactive, catalyze the side reaction to DE only when strong Lewis and/or Br?nsted acid sites are absent. Catalysts with only a strong Br?nsted acidity react selectively to form EOP. When strong Lewis acid sites are present in the catalyst, e.g. by introducing ZrO2 in SBA-15 or when extra-framework isolated Al 3+ sites are present in the mesoporous channels, a high selectivity to EMF was observed. The results indicate that EMF, DE or EOP can be obtained selectively by direct reaction of HMF with bioethanol by tuning the acidity of the catalyst. EMF is a value biodiesel component, but the results also evidence the possibility to obtain selectively EOP in a one-step reaction, opening interesting perspectives to produce valeric biofuels by subsequent selective hydrogenation.
- Lanzafame,Temi,Perathoner,Centi,MacArio,Aloise,Giordano
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- Selective Formation of Acetal by Photooxidation of Ethanol over Silica-supported Niobium Oxide Catalysts
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UV-irradiation of silica-supported niobium oxide suspended in liquid ethanol under atmospheric oxygen led to the selective production of 1,1-diethoxyethane.The absence of oxygen or UV-irradiation with wavelengths of λ > 320 nm remarkably suppressed the reaction.The activity normalized to the number of niobium ions suggests that the active site is highly dispersed niobate species.Ethanal is the primary product of the photooxidation and 1,1-diethoxyethane is formed by acid catalysis.
- Tanaka, Tsunehiro,Takenaka, Sakae,Funabiki, Takuzo,Yoshida, Satohiro
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- Iron and ruthenium heterobimetallic carbonyl complexes as electrocatalysts for alcohol oxidation: Electrochemical and mechanistic studies
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Carbonyl-containing Ru and Fe heterobimetallic complexes were prepared and tested as electrocatalysts for the oxidation of methanol and ethanol. GC analysis of the electrolyte solution during bulk electrolysis indicated that CpRu(CO) (μ-I) (μ-dppm) PtI2 (1), CpFe(CO) (μ-I) (μ-dppm) -PtI2 (2), and CpRu(CO) (μ-I) (μ-dppm) PdI2 (3) were catalysts for the electrooxidation of methanol and ethanol, while CpFe(CO) (μ-I) (μ-dppm) -PdI2 (4), CpRu(CO) I(μ-dppm) AuI (5), and CpFe(CO) I(μ-dppm) AuI (6) did not function as catalysts. The oxidation of methanol resulted in two-and four-electron oxidation to formaldehyde and formic acid, respectively, followed by condensation with unreacted methanol to yield dimethoxymethane and methyl formate as the observed products. The oxidation of ethanol afforded 1, 1 - diethoxyethane as a result of two-electron oxidation to acetaldehyde and condensation with excess ethanol. FTIR analysis of the headspace gases during the electrochemical oxidation of methanol indicated formation of CO2. Isotopic labeling experiments demonstrated that the CO2 resulted from oxidation of the CO ligand instead of complete oxidation of CH3OH.
- Serra, Daniel,Correia, Marie C.,McElwee-White, Lisa
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- Oxygen Effect on Photocatalytic Reaction of Ethanol over Some Titanium Dioxide Photocatalysts
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The suspensions of four kinds of TiO2 photocatalysts in ethanol have been studied under ultraviolet light in an atmosphere of Ar, air, or O2 at 25 deg C.The main products were acetaldehyde, acetaldehyde diethyl acetal (acetal), acetic acid, water, ethylen
- Iseda, Kozo
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- Improving the selectivity to C4 products in the aldol condensation of acetaldehyde in ethanol over faujasite zeolites
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The selective conversion of acetaldehyde to C4 products, minimizing the production of secondary (C6, C8) condensation products, could be a potential path in the production of butadiene from ethanol, a process of commercial interest. Therefore, we have investigated the selective aldol condensation of acetaldehyde in liquid phase over faujasite zeolites, NaX and NaY. Specifically, we have examined the influence of the number and location of the exchangeable cations, type of cations, and post-synthesis treatments on product selectivity. At 230 °C, NaY results in higher C4/(C6 + C8) product ratio than NaX, which can be explained in terms of the strength, density, and accessibility of basic sites, which are less favorable in NaX than NaY. In fact, the CO2 TPD measurements indicate the presence of three types of basic sites of varying strength, of which those with weak and medium strength are most important for the selective condensation. A confinement effect is observed when adding K to the NaY zeolite. The observed selectivity changes suggest that when larger cations partially occupy the supercages, the production of C8 products decreases, while C6 products increase. Also, post-synthesis washing treatments show significant variations in selectivity, which demonstrate the effects of partial occupation of the zeolite pores in the reaction. It is also shown that at a given conversion, the C4/(C6 + C8) ratio can be adjusted by modifying the micro/mesoporosity balance in the zeolite.
- Zhang, Lu,Pham, Tu N.,Faria, Jimmy,Resasco, Daniel E.
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- Photocatalytic ethanol to H2 and 1,1-diethoxyethane by Co(II) diphenylphosphinate/TiO2 composite
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Through a facile solvothermal method, the novel composites of cobalt(II) diphenylphosphinate/TiO2 have been synthesized and used for photocatalytic hydrogen production in ethanol solution. The chemical composition and surface morphology were an
- Li, Aihong,Li, Dongyang,Mao, Jianwei,Ge, Zhimeng,Guo, Jianping,Liu, Bo
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- Oxidation of terminal olefins by dioxygen in the presence of PdII(NH3)x/CuII/Li I/Cl- or PdII (or Pd0)/Zeolites/CuII/LiI/Cl- systems and a coreducer (ethanol)
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Simple ammonia complexes {cis-[PdCl2(NH3)2], [Pd(NH3)4]-Cl2 or [Pd(NO2)2(NH3)2]} with copper(II) chloride and LiCl or PdII (or Pd0) inserted into zeolite (faujasite Y or mordenite Z)/CuII/LiI/Cl- precursors in anhydrous ethanol catalyse the oxidation of terminal olefins to methyl ketones by dioxygen. One oxygen atom is incorporated into the olefinic substrate, while the other is involved in a cooxidation process of the solvent leading to the formation of water. With 1-octene and ethanol, octan-2-one can be obtained selectively (up to 99 %), acetaldehyde and diethyl acetal being the main cooxidation products. Chorohydridopalladium species are key intermediates in the isomerization of 1-alkenes; it appears that the introduction of NH3, NO2- or zeolite ligands reduces the extent of isomerization and subsequently the formation of isomeric ketones (octan-3-one and octan-4-one). Although homogeneous catalysis cannot be ruled out, the improved selectivities and variations of selectivity and conversion with different zeolites suggest that a "ship-in-a-bottle" catalysis may be important.
- Mohammedi, Ourida,Chemat, Farid,Bregeault, Jean-Marie
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- Reactions of palladium(i) carbonylacetate cluster with alcohols
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Reactions of a telranuclear palladium cluster (Pd(CO)(OAc)l4 with C,-Cj alcohols have been found to proceed simultaneously via several routes to form CO? and dialkyl carbonates, the products of oxidation of coordinated CO ligands, along with carbonyl compounds which form due to oxidation of the corresponding alcohols. Alkoxy, alkoxycarbonyl, and acyl palladium derivatives are shown to be the intermediates of the reactions studied.
- Chernysheva,Stromnova,Vargafiik,Moiseev
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- PALLADIUM ASSISTED OXIDATION OF CYCLOPENTENE BY MOLECULAR OXYGEN
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Dichlorobis(N,N-dialkylacetamide)palladium(II) complex catalyzes the oxidation of cyclopentene to cyclopentanone by molecular oxygen in alcoholic solvent, in which one atom of molecular oxygen in incorporated.
- Takehira, Katsuomi,Hayakawa, Takashi,Orita, Hideo
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- Effect of SSIE structure of Cu-exchanged β and Y on the selectivity for synthesis of diethyl carbonate by oxidative carbonylation of ethanol: A comparative investigation
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Cu-exchanged β and Y catalysts were investigated by oxidative carbonylation of ethanol in the gas-phase reaction. Cuβ catalyst has shown better catalytic selectivity for oxidative carbonylation of ethanol to diethyl carbonate (DEC), without the principal by-product 1,1-diethoxyethane (DEE) for CuY catalysts. In order to investigate the effect of zeolite structure on the selectivity for products, computational analysis of molecular dimensions and diffusion parameters of DEC and DEE within Cuβ and CuY catalysts zeolite framework has been performed using molecular mechanics and quantum mechanics methods. The computational analysis results are in good agreement with the experimental results to some extent. DEC having a kinetic diameter of 3.663 A? and the lowest energy barrier was formed preferentially over both zeolites. However, the DEE molecule was not detected among the products over Cuβ because of its greater kinetic diameter 6.059 A? and higher energy barrier. The special architecture of β zeolite did not allow the diffusion of DEE molecules through its pores. The formation of the higher sterically hindered DEE over CuY catalyst could be explained by involvement of the outer surface.
- Zhang, Pingbo,Huang, Shouying,Yang, Yang,Meng, Qingsen,Wang, Shengping,Ma, Xinbin
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- Synthesis and characterization of TiO2 nanotube supported Rh-nanoparticle catalysts for regioselective hydroformylation of vinyl acetate
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Three procedures: the impregnation-borohydride reduction procedure, the impregnation-alcohol reduction procedure and the impregnation-photoreducing procedure, were utilized for preparing TiO2 nanotube supported rhodium nanoparticle catalysts, in which rhodium acetate was used as a rhodium source. Catalysts were characterized with TEM, ICP, XPS and XRD; their catalytic performances for hydroformylation of vinyl acetate were evaluated. Of these catalysts prepared by three different methods, the catalyst prepared by the impregnation-photoreducing procedure showed the highest catalytic activity under the same reaction conditions. The effects of pressure of syngas, solvents, temperature, Rh content and reaction time on the hydroformylation were examined in detail. Under the optimized reaction conditions, the conversion of vinyl acetate can reach at 100%; the chemoselectivity for aldehydes was 74.70% and the regioselectivity for the branched aldehyde was 95%.
- Shi, Yukun,Hu, Xiaojing,Zhu, Baolin,Wang, Shurong,Zhang, Shoumin,Huang, Weiping
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- Direct ethanol condensation to diethyl acetal in the vapour phase at atmospheric pressure over CuNP/SBA-15 catalysts
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Of the biomass valorization technologies, bioethanol production and its selective conversion to diethyl acetal is of utmost importance to meet the increasing demand for bio-fuel additives. Direct synthesis of diethyl acetal in a single step from bioethanol using SBA-15-supported copper nanoparticle (CuNP/SBA-15) catalysts without using hydrogen acceptors and high pressure has been achieved as an alternative to the age-old two-step process via (i) partial oxidation of ethanol to acetaldehyde and (ii) acetaldehyde acetalization with ethanol. The prepared CuNP/SBA-15 catalysts with the SBA-15 support and copper nitrate (Cu (NO3)2·H2O) were characterized by using N2 adsorption, SEM, TEM, XRD, FT-IR, TPD of NH3, H2-TPR and N2O pulse chemisorption techniques. Analysis of the results showed the physico-chemical characterestics of these catalysts responsible for the acceptorless partial oxidation of ethanol to acetaldehyde and its acetalization with ethanol to yield diethyl acetal with high selectivity.
- Paleti, Gidyonu,Peddinti, Nagaiah,Gajula, Naveen,Kadharabenchi, Vasikerappa,Rao, Kamaraju Seetha Rama,Burri, David Raju
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- Oxygen-implanted MoS2 nanosheets promoting quinoline synthesis from nitroarenes and aliphatic alcohols via an integrated oxidation transfer hydrogenation-cyclization mechanism
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We herein report that MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinoline synthesis from basic nitroarenes and aliphatic alcohols. Different from common knowledge that the application of MoS2-based catalysts and above quinoline synthesis need anaerobic conditions, we conduct the heterogeneous catalysis under an unusual air atmosphere. Catalyst characterization and experimental results indicate that the MoOx clusters implanted in the MoS2 skeleton, not the coordinatively unsaturated Mo sites (CUS Mo), dominate the generation of quinolines. By overturning the catalysis perception that O2 adsorption on MoSx can deactivate the MoS2-based catalysts using an efficient method for in situ healing of the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 into the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and it offers 69-75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation-condensation mechanism, an integrated oxidation-transfer hydrogenation-cyclization mechanism is proposed over the O-MoS2 catalyst.
- Gao, Zhuyan,Huang, Zhipeng,Lu, Jianmin,Mu, Junju,Ren, Puning,Su, Kaiyi,Wang, Feng,Zhang, Chaofeng,Zhang, Shichao
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supporting information
p. 1704 - 1713
(2022/03/08)
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- Selective Chloride-Mediated Neat Ethanol Oxidation to 1,1-Diethoxyethane via an Electrochemically Generated Ethyl Hypochlorite Intermediate
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Selective primary alcohol oxidation to form aldehydes products without overoxidation to carboxylic acids remains a key chemistry challenge. Using simple alkylammonium chloride as the electrolyte with a glassy carbon working electrode in neat ethanol solvent, 1,1-diethoxyethane (DEE) was prepared with >95% faradaic efficiency (FE). DEE serves as a storage platform protecting acetaldehyde from overoxidation and volatilization. UV-vis spectroscopy shows that the reaction proceeds through an ethyl hypochlorite intermediate as the sole chloride oxidation product, and that this intermediate decomposes unimolecularly (rate constantk= (6.896 ± 0.516) × 10-4s-1) to form HCl catalyst and acetaldehyde, which undergoes rapid nucleophilic attack by ethanol solvent to form the DEE product. This indirect oxidation mechanism enables ethanol oxidation at much less positive potentials due to the fast kinetics for chloride anion oxidation.
- Bartlett, Bart M.,Li, Siqi
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supporting information
p. 15907 - 15911
(2021/10/12)
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- Method for producing vinyl ether
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The invention relates to a method for producing vinyl ether. The method comprises the following steps: (A) reacting excessive alcohol with acetaldehyde, and carrying out a continuous acetalation reaction by using immobilized superacid as a catalyst to obtain a first mixture; (B) carrying out oil-water separation and adsorption dehydration on the first mixture to obtain a second mixture; (C) carrying out acetal catalytic decomposition on the second mixture under the catalysis of a high-efficiency catalyst to obtain a third mixture; (D) rectifying the third mixture, and washing with water to obtain a vinyl ether product. According to the method, the high-temperature heating process of acetal is avoided, and the safety risk of operation is reduced; and an efficient acetal decomposition catalyst is adopted, and an acetal decomposition reaction is carried out at a low temperature, so that side reactions are few, and the selectivity of a main product is improved.
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Paragraph 0038-0073
(2020/07/15)
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- Method for liquid-phase catalytic selective hydrogenation of crotonaldehyde
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The invention relates to the field of chemical synthesis, and discloses a crotonaldehyde liquid-phase catalytic selective hydrogenation method, which comprises: carrying out a mixing reaction on ethanol and crotonaldehyde in the presence of a catalyst in an inert atmosphere under stirring under a crotonaldehyde liquid-phase catalytic selective hydrogenation condition to obtain a reaction product mixture, and separating out the catalyst to obtain the crotonaldehyde. Filtering to obtain crotonyl alcohol and 1, 1-diethoxyethane; the catalyst contains a carrier and a metal active component, an XPSmethod is adopted for characterization to obtain a metal inner-layer electron binding energy migration value delta E, delta E represents the difference between the inner-layer electron binding energyof the metal component in the catalyst and the binding energy of the metal oxide, and [delta]E is larger than 0.5 eV. According to the crotonaldehyde liquid-phase catalytic selective hydrogenation method, ideal selectivity and yield of crotonyl alcohol can be obtained, and acetal with high additional value can be obtained on the premise of sacrificing the selectivity of crotonyl alcohol as low aspossible, so that the product utilization rate is increased, the market competitiveness is enhanced, and the economic value is extremely high.
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Paragraph 0048-0074
(2020/12/29)
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- Promotion of catalytic properties of vanillin loaded MCM-41 by Cu(I) and Cu(II) for enhanced removal of quinoline contaminants
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In the present study, to enhance removal of quinoline contaminants using natural active component, vanillin was loaded onto the MCM-41 (Mobile Component Material) nanoparticles in a simple way. The product was divided into two parts, which were improved by Copper(I) and Copper(II) salts. Promoted synthetic nanocatalysts (Cu(I)/Van./MCM-41, and Cu(II)/Van./MCM-41) were characterized using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Mapping, Fourier-Transform Infrared Spectroscopy (FTIR), and BET/BJH (Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH)) techniques. To reach optimal conditions, experimental design was performed using Response Surface Methodology (RSM). The experiments were done with the aid of nanocomposites, in presence of ultraviolet radiation without any auxiliary oxidants. Degradation percentages were measured by an Ultraviolet (UV) spectrophotometer. The products were identified using Gas Chromatography–Mass (GC-Mass) technique, and some mechanisms for quinoline removal were proposed. The results indicated that Cu (I) showed better performance in enhanced removal of quinoline than Cu(II).
- Arjmand, Mehdi,Fazaeli, Reza,Ghorbani, Mohammad Hossein,Kamani, Mina
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p. 4833 - 4841
(2020/09/16)
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- Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation, Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives
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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C4 aldehydes via base-catalyzed aldol-condensation. Then, the resulting C4 adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.
- Faria, Jimmy,Komarneni, Mallik R.,Li, Gengnan,Pham, Tu,Resasco, Daniel E.,Ruiz, Maria P.,Santhanaraj, Daniel
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supporting information
p. 7456 - 7460
(2020/03/23)
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- METHOD FOR PRODUCING 1,3-BUTADIENE AND ACETALDEHYDE DIETHYL ACETAL
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PROBLEM TO BE SOLVED: To provide a method for producing 1,3-butadiene and acetaldehyde diethyl acetal that can synthesize high-value acetaldehyde diethyl acetal as a by-product with high efficiency in a 1,3-butadiene synthesis reaction and can reduce an amount of 5C or more hydrocarbons produced as a by-product having substantially no practical use other than the use as a fuel from an economical point of view. SOLUTION: The method for producing 1,3-butadiene and acetaldehyde diethyl acetal includes bringing ethanol into contact with a catalyst including at least one kind of metal selected from the group consisting of hafnium, zirconium, copper, zinc, tantalum, tungsten, magnesium and silicon under a pressure of 0.3 MPaG to 3 MPaG. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0050-0053
(2019/05/11)
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- Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
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Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
- Lyons,Crocker,Enders,Nguyen
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supporting information
p. 3993 - 3996
(2017/09/08)
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- Photocatalytic Conversion of a FeCl3–CCl4–ROH System
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The photocatalytic transformations of carbon tetrachloride and aliphatic primary alcohols in the presence of iron trichloride and a molar ratio of components FeCl3: CCl4: ROH = 1: 300: 2550 were studied. CCl4 is transformed into chloroform and hexachloroethane after exposure to a mercury lamp (250 W) to the FeCl3–CCl4–ROH system at 20°C, whereas the primary ROH alcohols are selectively oxidized into acetals (1,1-dialkoxyalkanes). The maximum conversion of CCl4 reaches 80%. The kinetics and mechanism of the photocatalytic conversion of the FeCl3–CCl4–ROH system are considered.
- Makhmutov
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p. 695 - 700
(2018/03/08)
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- Acetaldehyde as an ethanol derived bio-building block: An alternative to Guerbet chemistry
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In this work, we describe a highly selective poly-aldol condensation of acetaldehyde, which can readily be obtained via dehydrogenation of ethanol. The process operates under mild temperatures (100°C or less) using commercially available catalysts and exhibits excellent total carbon yield of C4+ products with good selectivity for C6 products. The products derived from the reactions described herein are shown to be candidate drop-in fuel replacements for compression ignition engines and precursors to valuable chemicals.
- Moore, Cameron M.,Staples, Orion,Jenkins, Rhodri W.,Brooks, Ty J.,Semelsberger, Troy A.,Sutton, Andrew D.
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p. 169 - 174
(2017/01/24)
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- The levels of fatty alcohol dehydrogenation coupling method for preparing aldehyde-acetal
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The invention discloses a method for preparing acetal by dehydrogenation coupling of first-stage fatty alcohol. The method comprises the following steps: adding alcohol reaction liquid to commercial titanium dioxide P25, and simultaneously adding a precious metals source solution; vacuumizing or introducing argon under magnetic agitation; stopping vacuumizing or introducing argon after oxygen in the system is removed; turning on an ultraviolet light source; reducing a precious metal source into precious metal particles by in-situ photocatalysis, and loading to the titanium dioxide surface; carrying out dehydrogenation coupling on catalyzed alcohol to form the acetal; controlling the reaction temperature at 10-70 DEG C and the reaction time at 10-72 hours; separating a catalyst through centrifugal participation, vacuum filtration or static precipitation after the reaction is ended, and then carrying out reduced pressure distillation to remove alcohol, so as to obtain the acetal product. The method has the advantages of high selectivity, high yield, low cost and the like, and is environmental friendly, and the purity can be up to over 97%.
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Paragraph 0025; 0026; 0042; 0044
(2016/10/08)
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- A catalytic conversion method for preparing pyruvate ester of lactic acid (by machine translation)
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A method for preparing pyruvate through catalytic conversion of lactic acid is provided; according to the method, with oxygen or air as an oxidant, alcohol as a solvent, and molybdovanadophosphoric heteropoly acid and/or tungstovanadophosphoric heteropoly acid as a catalyst, and by coupling of a catalytic oxidation reaction and an esterification reaction, lactic acid is converted into pyruvate by one step. The method directly adopts oxygen or air as the oxidant and is green and safe; the used raw material lactic acid is obtained directly from conversion of biomass resources, moreover, the reaction conditions are mild, and the method has important application prospects.
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Paragraph 0018
(2016/10/10)
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- Highly Efficient Process for Production of Biofuel from Ethanol Catalyzed by Ruthenium Pincer Complexes
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A highly efficient ruthenium pincer-catalyzed Guerbet-type process for the production of biofuel from ethanol has been developed. It produces the highest conversion of ethanol (73.4%, 0.02 mol% catalyst) for a Guerbet-type reaction, including significant amounts of C4 (35.8% yield), C6 (28.2% yield), and C8 (9.4% yield) alcohols. Catalyst loadings as low as 0.001 mol% can be used, leading to a record turnover number of 18 ?209. Mechanistic studies reveal the likely active ruthenium species and the main deactivation process.
- Xie, Yinjun,Ben-David, Yehoshoa,Shimon, Linda J. W.,Milstein, David
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supporting information
p. 9077 - 9080
(2016/08/05)
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- Decorating geometry- and size-controlled sub-20 nm Pd nanocubes onto 2D TiO2 nanosheets for simultaneous H2 evolution and 1,1-diethoxyethane production
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The morphological characteristics of metal play a pivotal role in affecting the activity of metal-semiconductor composite photocatalysts for solar energy conversion. In this article, geometry- and size-controlled sub-20 nm Pd nanocubes (NCs) have been fabricated and hybridized with 2D TiO2 nanosheets (TNS) to explore how the geometry and size of Pd influences the photocatalytic efficiency of Pd-based semiconductor composites. The photoactivity results evaluated by the dual-function photocatalytic system for simultaneous H2 evolution and 1,1-diethoxyethane (DEE) production suggest that Pd NCs endow TNS with a greatly enhanced photoactivity compared to Pd nanoparticles (NPs) supported on 2D TNS. The activation energy for H2 generation and the adsorption affinity between Pd and hydrogen molecules can be modulated by the geometry differences between Pd NCs and Pd NPs. Meanwhile, the activity of TNS-Pd NCs composites can be increased by decreasing the size of the Pd NCs from 17 to 7 nm, which is predominantly attributed to the more efficient capability of small Pd NCs to boost the separation and transportation of photoexcited electron-hole pairs. Our work not only fundamentally elucidates the relationship between the morphological characteristics of metal Pd and the photoactivity of Pd-based semiconductor composites, but also supplies a dual-purpose sustainable way for simultaneous H2 evolution and organic synthesis of fine chemicals.
- Weng, Bo,Quan, Quan,Xu, Yi-Jun
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supporting information
p. 18366 - 18377
(2016/12/09)
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- Synthesis of biodiesel without formation of free glycerol
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A new approach to the synthesis of biodiesel has been developed on the basis of alcoholysis of a triglyceride in combination with acetalization of glycerol with lower carbonyl compounds or acetals derived therefrom. A model synthesis of biodiesel not involving free glycerol has been accomplished using rapeseed oil and acid catalysts, as well as without a catalyst under generation of ethanol supercritical fluid; in the latter case, monoalkyl glycerol ethers are formed in addition to the expected cyclic ketals.
- Vol'eva,Belostotskaya,Komissarova,Koverzanova,Kurkovskaya,Usmanov,Gumerov
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p. 915 - 917
(2015/08/25)
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- Process for preparing a mixture of alcohols
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A method for preparing a mixture (M) including at least one alcohol (Aj), wherein said method includes a gas-phase oligomerization reaction of at least one alcohol (Ai) with a solid acid-base catalyst doped with one or more metals, said reaction being carried out in the presence of hydrogen and at a temperature of no less than 50° C. and strictly less than 200° C.
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Paragraph 0124-0141
(2015/01/06)
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- Oxidation of alcohols and activated alkanes with lewis acid-activated tempo
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The reactivity of MCl3(η1O) (M = Fe, 1; Al, 2; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) with a variety of alcohols, including 3,4-dimethoxybenzyl alcohol, 1-phenyl-2-phenoxyethanol, and 1,2-diphenyl-2-methoxyethanol, was investigated using NMR spectroscopy and mass spectrometry. Complex 1 was effective in cleanly converting these substrates to the corresponding aldehyde or ketone. Complex 2 was also able to oxidize these substrates; however, in a few instances the products of overoxidation were also observed. Oxidation of activated alkanes, such as xanthene, by 1 or 2 suggests that the reactions proceed via an initial 1-electron concerted proton-electron transfer (CPET) event. Finally, reaction of TEMPO with FeBr3 in Et2O results in the formation of a mixture of FeBr3(η1OH) (23) and [FeBr2(η1OH)]2(μ-O) (24), via oxidation of the solvent, Et2O.
- Nguyen, Thuy-Ai D.,Wright, Ashley M.,Page, Joshua S.,Wu, Guang,Hayton, Trevor W.
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p. 11377 - 11387
(2015/02/19)
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- Synthesis of Acetals Containing a Primary Amino Group
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Amino acetals of the general formula MeCH(OR)(OXNH2) (R = Et, Bu, X = CH2CH2, CH2CH2CH 2, CH2CMe2) were synthesized in 53-91% yield by acid-catalyzed reaction of N-(2-hydroxyethyl)-, N-(3-hydroxypropyl)-, and N-(2-hydroxy-1,1-dimethylethyl)-2,2,2-trifluoroacetamides with vinyl ethers, followed by removal of the trifluoroacetyl protection by alkaline hydrolysis. Pleiades Publishing, Ltd., 2012.
- Lobanova,Stankevich,Kukharev
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p. 1289 - 1296
(2013/02/21)
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- Chemo-and regioselective reaction of vinyl furfuryl ethers with alcohols
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Furfuryl and tetrahydrofurfuryl vinyl ethers reacted with various alcohols under mild conditions (20-25°C, 1-3 h, 1 wt % of CF3COOH) with high chemo- and regioselectivity to give the corresponding Markovnikov adducts at the vinyl group in up to 93% yield.
- Oparina,Vysotskaya,Stepanov,Gusarova,Trofimov
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p. 1162 - 1167
(2013/01/15)
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- METHOD FOR PRODUCING DIALKOXY ALKANES BY PARTIAL OXIDATION OF LOWER ALCOHOLS IN THE PRESENCE OF A CATALYST BASED ON MOLYBDENUM AND IRON
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The invention relates to a method for producing alkoxy alkanes by direct partial oxidation of a lower alcohol with a catalyst based upon mixed oxide containing molybdenum and at least one other metal selected from the metals that can assume a trivalent oxidation state such as Fe, Bi, Al, Cr, In, La, Sb, and/or a metal selected from Ni, Co, Cu, V, W, Ti, Ta, Nb, Mn, Sn, P.
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Page/Page column 8
(2011/06/10)
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- METHOD FOR THE SYNTHESIS OF DIALKOXY ALKANES BY MEANS OF THE SELECTIVE OXIDATION OF ALCOHOLS
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The invention relates to a method for the synthesis of dialkoxyalkanes by means of the partial selective oxidation of a light alcohol. According to said method, the light alcohol is oxidised in the presence of molecular oxygen or a gas containing molecular oxygen, and a solid oxidation catalyst based on at least one metal in a reactive medium comprising a gaseous phase containing an acid compound according to the Pearson classification, having a pKa of less than 6.3 in solution in water. The reaction is carried out in a vapour or in a liquid phase.
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Page/Page column 7
(2011/04/18)
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- B12-TiO2 hybrid catalyst for dehalogenation of organic halides
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A cobalamin derivative, cobyrinie acid, was effectively immobilized on TiO2, and the hybrid TiO2 was characterized by UV-vis, XPS, MALDI-TOFMS as well as TEM analysis. The hybrid TiO2 exhibits high reactivity for dehalogenation of various organic halides such as phenethyl bromide, benzyl bromide, and 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) under irradiation with UV light at room temperature. Copyright
- Shimakoshi, Hisashi,Sakumori, Emiko,Kaneko, Kenji,Hisaeda, Yoshio
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supporting information; experimental part
p. 468 - 469
(2010/03/04)
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- Process for the direct synthesis of trialkoxysilane
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This invention discloses a process to improve reaction stability in the Direct Synthesis of trialkoxysilanes. The process is particularly effective in the Direct Synthesis of triethoxysilane and its higher alkyl cognates providing improved triethoxysilane yields.
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Page/Page column 12
(2008/06/13)
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- Process for production of a composition useful as a fuel
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A process for the preparation of a fuel oil (diesel fuel or heating oil) composition which is a mixture of an alkanol tranesterified fatty acid ester triglyceride and an acetal of glycerol is described. The process preferably provides a prestep of the formation of at least some of the alkanol transesterified triglyceride containing the glycerol for use in the formation of the acetal of glycerol. The composition can also be formed from a reaction of 1,1- dimethoxy- or 1,1-diethoxyethane and glycerol to form the acetal in the alkanol transesterified triglyceride.
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Page/Page column 4
(2008/06/13)
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- Oxidation of monohydric and dihydric alcohols with CCl4 catalyzed by molybdenum compounds
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Mo(CO)6 catalyzed oxidation of alcohols and diols with tetrachloromethane. Primary oxidation products in reaction of alcohols with CCl4 are alkyl hypochlorites, and final products depending on the structure of initial alcohol are aldehydes (as acetals), ketones, chloroketones, and esters.
- Khusnutdinov,Shchadneva,Burangulova,Muslimov,Dzhemilev
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p. 1615 - 1621
(2007/10/03)
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