- Microwave promoted regeneration of carbonyl compounds from oximes using silica supported chromium trioxide
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Silica supported chromium trioxide was found to be an efficient reagent for the oxidative cleavage of oximes to the corresponding aldehydes and ketones in 'dry media', under microwave irradiation in a domestic microwave oven.
- Bendale, Pravin M.,Khadilkar, Bhushan M.
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Read Online
- Greener synthesis of pristane by flow dehydrative hydrogenation of allylic alcohol using a packed-bed reactor charged by pd/c as a single catalyst
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Our previous work established a continuous-flow synthesis of pristane, which is a saturated branched alkane obtained from a Basking Shark. The dehydration of an allylic alcohol that is the key to a tetraene was carried out using a packed-bed reactor charged by an acid–silica catalyst (HO-SAS) and flow hydrogenation using molecular hydrogen via a Pd/C catalyst followed. The present work relies on the additional propensity of Pd/C to serve as an acid catalyst, which allows us to perform a flow synthesis of pristane from the aforementioned key allylic alcohol in the presence of molecular hydrogen using Pd/C as a single catalyst, which is applied to both dehydration and hydrogenation. The present one-column-two-reaction-flow system could eliminate the use of an acid catalyst such as HO-SAS and lead to a significant simplification of the production process.
- Fukuyama, Takahide,Furuta, Akihiro,Hirobe, Yuki,Hyodo, Mamoru,Kasakado, Takayoshi,Ryu, Ilhyong
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- Effect of metal modification of titania and hydrogen co-feeding on the reaction pathways and catalytic stability in the acetone aldol condensation
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A stable performance of TiO2 catalysts for gas-phase acetone aldol condensation was observed when reduced metals were added (Pt or Ni, 1.5 wt%) and the reactions were conducted in presence of hydrogen. In both cases, the resulting metal-loaded catalysts are stable for 10 h, whereas continuous deactivation is observed for the parent TiO2 catalyst (573 K). Both the activation of the H2 molecule by metal nanoparticles and the change of the catalytic surface by metal insertion (in the case of Ni-loaded catalyst) enable suppressing oligomerization (by hindering enolates formation) and the strong adsorption of intermediates (by decreasing the concentration of high-strength acid-basic active sites), respectively. More interestingly, these metals allow to tune the selectivity of the reaction. Indeed, the Ni-loaded titania catalyst is highly selective for the synthesis of α,β-unsaturated ketones (selectivity to unsaturated C6 and C9 species >98%, at ~12% acetone conversion), whereas the Pt-loaded one is highly selective to the formation of saturated C6 and C9 ketones (MIBK and DIBK, with selectivities >95% at ~42% acetone conversion). The catalytic activity and stability of the two materials (Ni/TiO2 and Pt/TiO2) in both absence and presence of H2 are compared between them and with those of the parent TiO2. The results obtained by the reaction gas-phase analysis are supplemented through different solid characterization techniques (i.e., CO2-TPD and NH3-TPD, HRTEM, XPS, TPO, and DRIFTS).
- Quesada,Faba,Díaz, Eva,Ordó?ez, Salvador
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p. 133 - 144
(2019/08/01)
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- Iron-catalyzed urea synthesis: Dehydrogenative coupling of methanol and amines
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Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H2 as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.
- Lane, Elizabeth M.,Hazari, Nilay,Bernskoetter, Wesley H.
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p. 4003 - 4008
(2018/05/04)
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- METHOD OF FORMING DIBK
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A method of forming diisobutyl ketone (DIBK) is provided, which includes: (i) simultaneously providing methyl isobutyl ketone (MIBK), acetone, and hydrogen to a front end of a continuous serial reactor, wherein the MIBK and the acetone is condensed by a condensation catalyst to form an intermediate product; and (ii) hydrogenating the intermediate product to form a product by a hydrogenation catalyst at a back end of the continuous serial reactor, wherein the product includes DIBK.
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Paragraph 0014; 0015; 0016; 0017; 0018; 0019; 0020-0025
(2017/06/24)
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- Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals; An effective re-oxidant for TEMPO oxidation
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The novel oxidant of sodium hypochlorite pentahydrate (NaOCl·5H2O), which is now available for industrial and laboratory use has several advantageous properties. The crystalline material has 44% of NaOCl, contains minimal sodium hydroxide and sodium chloride, and the aqueous solution indicates pH 11-12. Herein, NaOCl·5H2O crystals are examined for use as an oxidant for primary and secondary alcohols, with or without nitroxyl radicals, in the presence or absence of phase-transfer catalysts. The pentahydrate crystals alone (without nitroxyl radicals) demonstrate a powerful oxidizing ability, converting secondary alcohols to the corresponding ketones. In the presence of TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) or 1-Me-AZADO (1-methyl-2-azaadamantane N-oxy radical), sterically hindered secondary alcohols are oxidized without pH adjustment. A proposed mechanism for the oxidation is discussed.
- Okada, Tomohide,Asawa, Tomotake,Sugiyama, Yukihiro,Iwai, Toshiaki,Kirihara, Masayuki,Kimura, Yoshikazu
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p. 2818 - 2827
(2016/05/19)
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- Synthesis of Acetone-Derived C6, C9, and C12Carbon Scaffolds for Chemical and Fuel Applications
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A simple, inexpensive catalyst system (Amberlyst 15 and Ni/SiO2–Al2O3) is described for the upgrading of acetone to a range of chemicals and potential fuels. Stepwise hydrodeoxygenation of the produced ketones can yield branched alcohols, alkenes, and alkanes. An analysis of these products is provided, which demonstrates that this approach can provide a product profile of valuable bioproducts and potential biofuels.
- Moore, Cameron M.,Jenkins, Rhodri W.,Janicke, Michael T.,Kubic, William L.,Polikarpov, Evgueni,Semelsberger, Troy A.,Sutton, Andrew D.
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p. 3382 - 3386
(2016/12/27)
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- METHOD FOR OXIDIZING ALCOHOLS
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Oxidation of alcohols to carbonyl compounds is one of important basic reactions in organic synthesis. The present invention provides an oxidation method of alcohols, which secures high productivity and safely and conveniently obtains a targeted substance with good selectivity at high yields. The oxidation method of alcohols oxidizes alcohols represented by general formula 1, thereby manufacturing carbonyl compounds derived from the alcohols, and uses sodium hypochlorite pentahydrate as an oxidizing agent in the presence or absence of a catalyst. (In general formula 1, R^1 represents an alkyl group, an aryl group or an aralkyl group, and R^2 represents an alkyl group, an aryl group, an aralkyl group or a hydrogen atom.)COPYRIGHT KIPO 2015
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Paragraph 0034-0036; 0037-0038
(2016/12/01)
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- Ru-C-ZnO composite catalysts for the synthesis of methyl isobutyl ketone via single step gas phase acetone self-condensation
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Ruthenium/activated charcoal (Ru-C) was modified by a solid-solid interaction method with synthesized nano-zinc oxide (n-ZnO). Three different ratios of Ru-C:n-ZnO (1:2, 1:1 and 3:2) were used to prepare Ru-C-ZnO composite catalysts. These were used in the gas-phase, one-step self-condensation of acetone to methyl isobutyl ketone (MIBK). The composite catalyst (1:1 ratio) contained 2.5 wt% Ru showed superior conversion of acetone and selectivity for MIBK. Furthermore, this catalyst showed good consistency for MIBK formation for 100 h without any deactivation. Characterization of the catalysts revealed that balanced hydrogenation and acid-base functional character is crucial to obtain high catalytic performance.
- Bagabas, Abdulaziz A.,Mokhtar, Mohamed,Akhmedov, Vagif M.,Narasimharao, Katabathini,Basahel, Sulaiman N.,Al-Rabiah, Abdulrahman
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p. 1278 - 1288
(2014/07/21)
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- Kinetics and mechanism of oxidation of aliphatic secondary alcohols by benzyltrimethylammonium chlorobromate
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Oxidation of several secondary alcohols by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to BTMACB and the alcohols. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is chlorobromate ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (kH/kD = 5.61 at 298 K). The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. The reaction is susceptible to both the polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.
- Sharma, Pradeep K.
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p. 2702 - 2706
(2014/06/09)
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- Sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals as an extraa?ordinary oxidant for primary and secondary alcohols
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Sodium hypochlorite pentahydrate crystals containing less free sodium hydroxide and sodium chloride have been developed as an improved oxidant. Primary and secondary alcohols have been oxidized to the corresponding aldehydes and ketones with ?NaOCl·5H2O in the presence of TEMPO/Bu4NHSO4. This new oxidation method does not require pH adjustment and is applicable to sterically hindered secondary alcohols. Georg Thieme Verlag Stuttgart New York.
- Okada, Tomohide,Asawa, Tomotake,Sugiyama, Yukihiro,Kirihara, Masayuki,Iwai, Toshiaki,Kimura, Yoshikazu
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p. 596 - 598
(2014/03/21)
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- MONOMER, POLYMER, RESIST COMPOSITION, AND PATTERNING PROCESS
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A polymer comprising recurring units derived from a (meth)acrylate monomer of tertiary ester type having branched alkyl on alicycle is used to form a resist composition. When subjected to exposure, PEB and organic solvent development, the resist composition is improved in dissolution contrast.
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- Dramatic promotion of copper-alumina catalysts by sodium for acetone trimerisation
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Na-promoted Cu-Al materials are efficient multifunctional catalysts for the direct conversion of gas phase acetone to diisobutyl ketone (DIBK) with unprecedented yields (up to 31%). The Na content is a major parameter determining the stability and the catalytic performance of these materials.
- Ligner, Emanuelle,Meunier, Frederic,Travert, Arnaud,Maury, Sylvie,Cadran, Nicolas
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p. 2480 - 2483
(2014/07/22)
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- Catalytic synthesis of cumene from benzene and acetone
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The reaction of benzene hydroalkylation with acetone on bifunctional catalysts has been studied and the principal features of the process have been revealed, wherein the catalysts contain a copper oxide-copper chromite binary system as a hydrogenating component and BEA, MOR, FAU, or MFI zeolite as an alkylating component. It has been found that the use of the catalyst based on the mixed copper-chromium oxide and mordenite, running the process at 150 C and 3 MPa, and feedstock dilution with benzene (C6H6: C 3H6O = 9: 1) facilitate increasing of the yield of cumene as a main product.
- Shutkina,Ponomareva,Ivanova
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- COMPOSITE CATALYST AND USING THE SAME FOR MAKING ISOPROPYL ALCOHOL
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Isopropyl alcohol is a very useful chemical that is widely used in the industry as a solvent. Economical and easy process to make ispopropyl alcohol using novel composite catalyst is described in the instant application. Production of isopropyl alcohol (IPA) from dimehtyl ketone (DMK) and hydrogen (H2) in gas-phase using a ruthenium nano-particle-supported on activated charcoal/nano-zinc oxide composite catalyst is described. Gas phase production of isopropyl alcohol using DMK and hydrogen is also described using optimal time on stream, temperature, catalyst ratio and DMK/H2 ratio. Ruthenium nano-zinc oxide composite catalyst is formulated using different ratios of ruthenium activated charcoal and n-ZnO is described. CAT-IV is shown to be the best performer for the efficient production of isopropyl alcohol.
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Page/Page column 3
(2012/08/27)
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- Low pressure one-step gas-phase process for production of methyl isobutyl ketone
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A low-pressure one-step gas-phase process for the production and recovery of methyl isobutyl ketone (MIBK) is disclosed. One-step gas-phase synthesis of MIBK from acetone and hydrogen over nano- Pd/nano-ZnCr2O4 catalyst at atmospheric pressure is used as an example. The said process is designed to recover the additional heat associated with the reactor effluent via heating acetone feed and recycle (mixed acetone) before entering the reactor. A compressor is introduced to the gas-phase process to increase slightly the reactor effluent pressure before this effluent is cooled and fed to a flash drum. The compressed reactor effluent is used to preheat hydrogen feed and recycle (mixed hydrogen) before entering the reactor. The separation scheme of low-pressure one-step gas-phase process comprises of several distillation columns used for MIBK separation and purification.
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Page/Page column 9
(2013/02/27)
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- Synthesizing and utilizing novel nano crystalline zinc chromate supported nano palladium catalyst
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Several metal-supported catalyst compositions based on nano-crystalline zinc oxide were synthesized and characterized by X-ray powder diffraction (XRD), Carbon dioxide temperature programmed desorption (CO2 TPD), and nitrogen adsorption at ?196° C. The Pd-supported nano-ZnO mixed with different oxides such as Cr2O3, CrO3, MgO, and γ-Al2O3 showed high catalytic activity in acetone condensation in gas-phase process under hydrogen flow. This reaction involves the base-acid coupling of acetone to form mesityl oxide, followed by its hydrogenation to methyl isobutyl ketone (MIBK). The novel catalyst 1% wt. n-Pd/n-ZnCr2O4 was utilized during gas-phase reaction during production of MIBK. MIBK selectivity was 70-72% at 66-77% acetone conversion at 300-350° C. Diisobutyl ketone (DIBK) was the main by-product, with a total MIBK+DIBK selectivity up to 88%. The prepared catalysts showed stable activity and may be used repeatedly and for a longer period of time.
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Page/Page column 6-7
(2011/06/23)
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- LOW PRESSURE ONE-STEP GAS-PHASE PROCESS FOR PRODUCTION OF METHYL ISOBUTYL KETONE
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A low-pressure one-step gas-phase process for the production and recovery of methyl isobutyl ketone (MIBK) is disclosed. One-step gas-phase synthesis of MIBK from acetone and hydrogen over nano-Pd/nano-ZnCr2O4 catalyst at atmospheric pressure is used as an example. The said process is designed to recover the additional heat associated with the reactor effluent via heating acetone feed and recycle (mixed acetone) before entering the reactor. A compressor is introduced to the gas-phase process to increase slightly the reactor effluent pressure before this effluent is cooled and fed to a flash drum. The compressed reactor effluent is used to preheat hydrogen feed and recycle (mixed hydrogen) before entering the reactor. The separation scheme of low-pressure one-step gas-phase process comprises of several distillation columns used for MIBK separation and purification.
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Page/Page column 6
(2011/10/12)
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- Multifunctional catalysis by Pd@MIL-101: One-step synthesis of methyl isobutyl ketone over palladium nanoparticles deposited on a metal-organic framework
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Palladium nanoparticles deposited on a chromium terephthalate MIL-101 is a highly efficient multifunctional catalyst for the one-step synthesis of methyl isobutyl ketone, with significantly higher activity than palladium on traditional materials, such as metal oxides and zeolites.
- Pan, Yingyi,Yuan, Bizhen,Li, Yingwei,He, Dehua
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supporting information; experimental part
p. 2280 - 2282
(2010/07/09)
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- One-step conversion of acetone to methyl isobutyl ketone over Pd-mixed oxide catalysts prepared from novel layered double hydroxides
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Novel layered double hydroxides, [MAl4(OH)12](NO3)2snH2O (M = (Li+)2, Co2+, Ni2+, Cu2+, Zn2+), impregnated with palladium, have proved to be precursors to active bifunctional mixed oxide catalysts for the one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and H2 in the gas phase. High acetone conversions of up to 76% and MIBK selectivities of up to 91% were recorded at a reaction temperature of 250 °C and atmospheric pressure. The palladium catalysts based on Li and Zn layered double hydroxides displayed efficient catalytic performances at the low reaction temperature of 120 °C. Powder XRD and 27Al MAS NMR showed that initially crystalline layered double hydroxides transformed to amorphous mixed oxide materials upon catalyst activation at 250 °C under H2.
- Hetterley, Robert D.,Mackey, Richard,Jones, James T.A.,Khimyak, Yaroslav Z.,Fogg, Andrew M.,Kozhevnikov, Ivan V.
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scheme or table
p. 250 - 255
(2009/02/07)
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- Pd supported on ZnII-CrIII mixed oxide as a catalyst for one-step synthesis of methyl isobutyl ketone
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Pd metal supported on ZnII-CrIII mixed oxide is an efficient bifunctional catalyst for the one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and H2 in the gas and liquid phases. The reaction involves acid-catalysed condensation of acetone to mesityl oxide, followed by its hydrogenation to MIBK. Diisobutyl ketone (DIBK) is a useful byproduct in this process. Zn-Cr oxides (Zn/Cr = 20:1-1:30) are prepared by coprecipitation of ZnII and CrIII hydroxides. The texture and acid properties (i.e., the nature, density, and strength of acid sites) of Zn-Cr oxides, as well as the Pd dispersion in the catalysts, are thoroughly characterised. For both the continuous gas-phase process and the batch liquid-phase process, the preferred catalyst formulation is 0.3 wt% Pd on the amorphous Zn-Cr (1:1) oxide (SBET = 132 m2 / g) having Lewis acid sites (1.2 mmol/g density) with an enthalpy of NH3 adsorption of - 155 kJ / mol. Both processes produce MIBK with a selectivity of 70-78% and 90% MIBK + DIBK total selectivity at 38-40% acetone conversion. Evidence is provided that hydrogenation of mesityl oxide to MIBK is the rate-limiting step in the gas-phase process.
- Al-Wadaani, Fahd,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.
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scheme or table
p. 199 - 205
(2009/02/07)
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- ALCOHOL OXIDATION CATALYST AND METHOD OF SYNTHESIZING THE SAME
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An organic oxidation catalyst for alcohols which is environmentally less harmful and with which efficient oxidation can be conducted. The oxidation catalyst for alcohols is a 1-alkyl-2-azadamantan-N-oxyl which has a nitroxyl group incorporated in the adamantane skeleton and was synthesized from as a base material a bicyclic compound obtained by the Grob-type ring-opening reaction of 1,3-adamantanediol. Due to the nitroxyl group on the adamantane skeleton, the ±-position hydrogen is stabilized based on Bredt's rule and the stability of the oxoammonium group generated by the oxidation thereof is ensured. Compared to TEMPO, which is a conventional oxidation catalyst, this catalyst is reduced in steric hindrance and is usable in a wide range of reaction fields. Because of this, not only a primary alcohol but a secondary alcohol having a sterically complicated structure, which has been difficult to oxidize with TEMPO, can be oxidized at a high efficiency.
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Page/Page column 12-14
(2008/06/13)
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- Palladium catalyzed mild reduction of α,β-unsaturated compounds by triethylsilane
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The palladium(II) chloride/triethylsilane system has been successfully applied for the selective hydrogenation of the carbon-carbon double bond of α,β-unsaturated ketones to yield the corresponding saturated carbonyl compounds. The reaction takes place under mild conditions and affords high yields.
- Mirza-Aghayan, Maryam,Boukherroub, Rabah,Bolourtchian, Mohammad,Rahimifard, Mahshid
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p. 5113 - 5116
(2008/02/13)
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- METHOD TO MAKE METHYL ISOBUTYL KETONE AND DIISOBUTYL KETONE
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An improved method for the manufacture of MIBK and DIBK from DMK and/or IPA, by reacting, in the presence of an aldol condensation catalyst, a gaseous mixture comprising hydrogen and DMK and/or IPA. The improvement is the use of a reaction pressure greater than 207 kPa (30 psig) to increase the ratio of MIBK to DIBK. In addition a method for the manufacture of MIBK and DIBK by reacting, in the presence of an aldol condensation catalyst, a gaseous mixture consisting essentially of DMK and/or IPA and optionally water.
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Page/Page column 7; 1/3
(2008/06/13)
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- Kinetics and mechanism of oxidation of secondary alcohols by benzyltriethylammonium chlorochromate
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Oxidation of several aliphatic secondary alcohols by benzyltriethylammonium chlorochromate in dimethylsulfoxide leads to the formation of corresponding ketones. The reaction is first order each in benzyltriethylammonium chlorochromate and the alcohols. The reaction is catalysed by hydrogen ions. Hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of benzhydrol-α-d exhibits a substantial primary kinetic isotope effect (kH/kD = 6.12 at 288 K). Oxidation of 2-propanol has been studied in nineteen different organic solvents. The solvent effect has been analysed using Taft's and Swain's multiparametric equations. The reaction has been subjected to both polar and steric effects of the substituents. A mechanism involving transfer of hydride ion from alcohol to the oxidant via a chromate ester is also proposed.
- Kaur, Ravdeep,Soni, Neelam,Sharma, Vinita
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p. 2441 - 2445
(2007/10/03)
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- Conjugate reduction of α,β-unsaturated carbonyl compounds promoted by nickel nanoparticles
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The system composed of nickel(II) chloride, lithium metal, a catalytic polymer-supported arene, and ethanol, has been efficiently applied to the conjugate reduction of a variety of α,β-unsaturated carbonyl compounds (ketones and carboxylic acid derivatives) under very mild reaction conditions. Georg Thieme Verlag Stuttgart.
- Alonso, Francisco,Osante, I?aki,Yus, Miguel
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p. 3017 - 3020
(2008/02/12)
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- One-step synthesis of methyl isobutyl ketone from acetone catalysed by Pd supported on ZnII-CrIII mixed oxide
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Pd metal (0.1-1 wt%) supported on ZnII-CrIII (1:10) mixed oxide was found to be an efficient bifunctional catalyst for the one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and H2 in gas- and liquid-phase processes. The reaction involves the acid-catalysed condensation of acetone to form mesityl oxide, followed by its hydrogenation to MIBK. The gas-phase reaction produces MIBK with a selectivity up to 78% at 40-66% acetone conversion (200-350 °C, ambient pressure). Diisobutyl ketone (DIBK) is the main byproduct, with a total MIBK + DIBK selectivity of up to 93%. The catalyst reaches a steady state in ca. 1 h and shows constant activity and selectivity for at least 50 h on stream. The liquid-phase reaction yields MIBK with up to 83% selectivity and total selectivity to MIBK + DIBK up to 9 at 56% acetone conversion (200 °C, 5 bar H2 pressure). As a catalyst support, the amorphous Zn-Cr oxide calcined at 300 °C provides higher catalytic activity than the crystalline Zn-Cr oxide calcined at 400 °C, probably due to the lower surface area of the crystalline oxide. XRD of 0.3-1%Pd/Zn-Cr oxide showed no pattern of Pd metal, indicating a fine dispersion of Pd particles in the catalyst.
- Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.
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p. 286 - 292
(2007/10/03)
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- Multifunctional catalysis by Pd-polyoxometalate: One-step conversion of acetone to methyl isobutyl ketone
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Pd metal supported on Cs2.5H0.5PW12O 40 is an efficient bifunctional catalyst for the one-step conversion of acetone to methyl isobutyl ketone in gas and liquid phase. The Royal Society of Chemistry 2006.
- Hetterley, Robert D.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.
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p. 782 - 784
(2008/02/03)
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- Process for hydrolyzing di-isopropyl ether to isopropyl alcohol by catalytic distillation using a solid acid catalyst
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The invention relates to the production of isopropyl alcohol from di-isopropyl ether by catalytic distillation. The process solves, in particular, problems associated with the Sulfuric Acid Process.
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Page/Page column 6-7
(2008/06/13)
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- Preparation, characterization of MCM-49 and catalytic performance of Pd/MCM-49 catalysts in one-step synthesis of MIBK from acetone
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Highly crystalline and pure MCM-49 was hydrothermally synthesized by a dynamic method, and it was used as supports to prepare Pd/MCM-49 catalysts by ion-exchange method. The physicochemical properties of the samples were characterized by XRD, TEM, TG-DTG and ICP. MCM-49 synthesized was markedly different from those in previous reports, showing much smaller crystals. One-step synthesis of methyl isobutyl ketone from acetone was investigated over Pd/MCM-49. These catalysts showed a high reactivity and selectivity to MIBK, reaching a conversion of 35.6% and a selectivity of 85% to MIBK. Stable MIBK yields were obtained during 60 h of time on stream.
- Yang,Wang,Yu,Xu,Liu,Jing,Wu
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p. 121 - 127
(2007/10/03)
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- Direct synthesis of methyl isobutyl ketone in gas-phase reaction over palladium-loaded hydroxyapatite
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Several compositions of palladium-loaded calcium hydroxyapatite Pd(x)/CaHAp were prepared and characterized by XRD, IR, and UV-visible spectroscopy and temperature-programmed reduction (TPR). The acid-base properties of the samples were studied with the use of butan-2-ol conversion and IR spectroscopy coupled with lutidine adsorption/desorption. Calcium hydroxyapatite bears Lewis acid sites of moderate strength and a limited number of Bronsted acid sites, which produce butenes by dehydration. The selectivity of the dehydrogenation reaction (formation of methyl ethyl ketone) is very limited in the absence of oxygen but indicates the existence on the surface of phosphate of basic sites that are as essential as the acid sites in the direct synthesis of methyl isobutyl ketone (MIBK) from acetone and H2. Dispersion of Pd on the hydroxyapatite introduces redox properties and the bifunctionality needed in the hydrogenation of mesityl oxide (MO). Temperature-programmed reduction (TPR) of Pd(x)/CaHAp catalysts shows a sharp peak of H2 consumption between 268 and 276 K, depending on palladium loading, followed by a negative peak at about 338 K, which is associated with the decomposition of β-PdH. Hydrogen chemisorption measurements carried out at 353 K allowed the determination of the size of palladium particles, which varies between 8 and 28 nm. The Pd(x)/CaHAp catalysts showed good performance in the low-pressure one-step synthesis of MIBK. They are stable under the experimental conditions, and they exhibit a MIBK and MIBC selectivity that reaches 92% for a conversion of 22% and an optimal Pd loading of 2 wt%. Other parameters of the reaction (such as temperature of reaction, residence time, H2/acetone ratio) were studied. They all play an important role in acetone conversion and product distribution. However, the reaction temperature has the most significant influence, since a maximum of the global conversion was observed at 423 K.
- Cheikhi, Nabil,Kacimi, Mohamed,Rouimi, Mohamed,Ziyad, Mahfoud,Liotta, Leonarda F.,Pantaleo, Giuseppe,Deganello, Giulio
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p. 257 - 267
(2007/10/03)
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- Specific features of thermal degradation of polypropylene in the presence of magnesium hydroxide
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Specific features of thermal oxidative degradation of polypropylene and its composite with Mg(OH)2 were studied by pyrolytic gas chromatography-mass spectrometry and thermal gravimetric analysis.
- Koverzanova,Usachev,Shilkina,Lomakin,Gumargalieva,Zaikov
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p. 445 - 448
(2007/10/03)
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- N-tert-Butylbenzenesulfenamide-catalyzed oxidation of alcohols to the corresponding carbonyl compounds with N-chlorosuccinimide
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N-tert-Butylbenzenesulfenamide (1)-catalyzed oxidation of various primary and secondary alcohols to the corresponding aldehydes and ketones was efficiently carried out by using N-chlorosuccinimide (NCS) in the coexistence of potassium carbonate and molecular sieves 4? at easy-to-control temperatures ranging from 0°C to room temperature. The present catalytic oxidation was performed without giving any damage to the functional groups in alcohols, and was particularly effective in the oxidation of alcohols that formed labile aldehydes because of its mild reaction conditions. Further, selective oxidation of primary hydroxy groups took place in 1-catalyzed oxidation of several diols. Mechanistic investigation suggested that the chlorination of the sulfenamide 1 by NCS led to the formation of a key species, N-tert-butylbenzenesulfinimidoyl chloride (2), which in turn oxidized alcohols in the presence of potassium carbonate to afford carbonyl products by accompanying regeneration of the catalyst 1.
- Matsuo, Jun-Ichi,Iida, Daisuke,Yamanaka, Hiroyuki,Mukaiyama, Teruaki
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p. 6739 - 6750
(2007/10/03)
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- Kinetics and mechanism of the oxidation of secondary alcohols by tetrabutylammonium tribromide
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Oxidation of several secondary alcohols by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to TBATB and the alcohols. The reaction failed to induce polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is tribromide ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (k H/kd = 5.15 at 298 K). The effect of solvent composition indicates that the rate increases with an increase in polarity of the solvent. The reaction is susceptible to both polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.
- Gosain, Jaya,Sharma, Pradeep K.
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p. 815 - 818
(2007/10/03)
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- Low-pressure one-step synthesis of methyl isobutyl ketone from acetone and hydrogen over metal modified solid base catalysts
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One-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen over metal modified solid base catalysts has been studied at atmospheric pressure and 175-250 °C by using a fixed-bed, integral-flow reactor. Two types of catalysts have been utilized: (1) zeolites modified with palladium (Pd/Kβ, Pd/KZSM-5); and (2) metal oxides modified with sodium and palladium (Pd/Na/MgO, Pd/Na/NaOH/γ-Al2O3). The catalyst properties were characterized by the methods of atomic absorption, temperature-programmed desorption and gas adsorption. Sodium vapor deposition on magnesia, followed by impregnation with tetraamine palladium (II) chloride apparently enhances the catalyst basicity as compared with that of magnesia supported palladium. For catalysts with different supports, the base amount decreases in the order of Pd/Na/MgO > Pd/Na/NaOH/γ-Al2O 3 > Pd/KZSM-5 > Pd/Kβ, in accordance with the catalytic activities. As the amount of sodium or palladium in Pd/Na/MgO increases, the catalyst base amount, acetone conversion and MIBK selectivity are also enhanced to a maximum and then decline. Better catalytic results were attained at a higher pretreating temperature of hydrogen on the catalyst. The optimum conditions for this reaction are 0.5%Pd/0.47%Na/MgO pretreated with hydrogen at 400 °C, reaction temperature 200 °C, acetone/hydrogen mol ratio 1, and W/Fa 6g·h/mol. Under these conditions, the acetone conversion and MIBK yield are 47.3% and 30.7%, respectively, at 480 min time-on-stream. The reaction network and reaction mechanism for the formation of MIBK are proposed and discussed.
- Lin, Kai-Hsun,Ko, An-Nan
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p. 935 - 942
(2007/10/03)
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- Bifunctional metal/base catalysts (Pt/X) for the direct synthesis of MIBK from acetone
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The synthesis of MIBK was studied over Pt supported on NaX and CsX zeolites. The activity increased as both the temperature and the H2/Ac ratio were increased. Temperature had also a beneficial effect on the selectivity to MIBK but the H2/Ac ratio had an opposite effect. Activities and selectivities were always higher for Pt/NaX than for Pt/CsX. For Pt/NaX, increasing the reduction temperature increased the activity but decreased the selectivity to MIBK. Both catalysts were quite stable and selectivities to MIBK of 70% were obtained over PtNaX at 613 K and H2/Ac = 0.5. The absence of both strong acidic and strong basic sites and a proper balance between metallic and basic sites are responsible for the behavior observed.
- Mattos, Lisiane V.,Noronha, Fabio B.,Monteiro, Jose Luiz F.
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p. 166 - 176
(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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- One-step synthesis of methyl isobutyl ketone from acetone and hydrogen over Cu-on-MgO catalysts
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The one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen over Cu-on-MgO catalysts was studied at atmospheric pressure in a fixed bed continuous flow reactor. Catalysts with various copper loadings were prepared by impregnation and coprecipitation and characterized by BET and Cu(O) surface area measurements, XRD, SAXS, thermal analysis, and basicity measurements. A 3.46% Cu-on-MgO prepared by coprecipitation, calcined at 723 K for 4 h, and pretreated in hydrogen (673 K, 1 h) showed high and stable activity and selectivity in the production of MIBK. Under the best conditions (553 K reaction temperature, 15% molar excess of hydrogen to acetone, and 1920 ml h-1 gcat-1 space velocity) MIBK is formed in 45-48% yield (60-80% conversion and 60-75% selectivity) over a period of 24 h-on-stream. The results of deuterium labeling studies point to metallic sites catalyzing deuterium exchange and basic sites catalyzing dimerization of acetone, leading eventually to MIBK with high deuterium content. A comparison of deuterium contents of acetone, mesityl oxide (MO), and MIBK shows that the surface deuterium pool is highly diluted with hydrogen, formed during the exchange process. Deuterium incorporation during the saturation of the carbon-carbon double bond of MO to form MIBK, therefore, is less than expected. Formation of diisobutyl ketone with very low deuterium content is suggested to result from the involvement of strongly bound surface intermediates with long residence time not allowing exchange process.
- Chikan, Viktor,Molnar, Arpad,Balazsik, Katalin
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p. 134 - 143
(2007/10/03)
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- Efficient catalytic reduction of ketones with formic acid and ruthenium complexes
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The ruthenium complex (η5-C4Ph4COHOC4Ph4-η5)( μ-H)(CO)4Ru2 and its phenyl ring-substituted derivatives were found to act as efficient catalysts in reduction reactions of aldehydes and ketones to alcohols, using formic acid as H source. Excess formic acid accelerates the reaction, and the corresponding formate esters were isolated as sole products. Turnover numbers of up to 8000 (alcohols) and 11000 (formate esters) were attained, with yields in the order of 90%. Alkenes are not reactive, however, double bonds conjugated to a carbonyl group are selectively reduced under the reaction conditions. The reaction is compatible with a variety of ketones, but with aliphatic aldehydes the reaction is not selective, inasmuch as aldol condensation products are formed.
- Menashe, Naim,Salant, Einat,Shvo, Youval
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- Separation of methylene chloride from tetrahydrofuran by extractive distillation
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Methylene chloride is difficult to separate from tetrahydrofuran by conventional distillation or rectification because of the proximity of their vapor pressures. Methylene chloride can be readily separated from tetrahydrofuran by extractive distillation. Effective agents are 1-pentanol, 1,2-butanediol and 3-nitrotoluene.
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- ORALLY ACTIVE RENIN INHIBITORS
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This invention relates to compounds of the formula STR1 wherein Q, Z, D, E, R 3, R 4, R 5 and R 6 are defined as below, and the pharmaceutically acceptable salts thereof are disclosed. The compounds are useful as antihypertensive agents.
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- Studies on hydrogen storage alloy, Mg2Ni: catalytic activity and XPS
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Catalytic activity of hydrogen storage alloy, Mg2Ni and modified Mg2Ni(O-Mg2Ni) has been studied using decomposition of 2-propanol as test reaction.Besides dehydrogenation activity, Mg2Ni shows some activity towards the formation of condensation products, viz. mesityl oxide, isobutyl methyl ketone and diisobutyl ketone.XRD of spent Mg2Ni indicate disproportionation of Mg2Ni to MgO, Ni and NiO under reaction conditions, while XP spectra show coke formation on its surface.On O-Mg2Ni the activity is reproducible with only acetone as the product.The activity, selectivity and stability have been explained based on the difference in their surface composition as revealed by XPS studies.
- Padmasubhashini, V,Murthy, I A P S,Kumar, M P Sridhar,Swamy, C S
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p. 1101 - 1105
(2007/10/02)
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- Decomposition of Isopropyl Alcohol on Oxidised Intermetallic Compound LaNi5
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The catalyst formed by oxidation of LaNi5 is found to have higher specific activity and lower activation energy for the decomposition of isopropyl alcohol when compared with the corresponding conventionally prepared supported metal catalyst.Both the catalysts lead to the formation of condensation products like mesityl oxide, isobutyl methyl ketone and diisobutyl ketone in addition to acetone.A probable mechanistic route for the formation of the condensation products is proposed.The condensation ability of these supported catalysts is attributed to the basic nature of La2O3.
- Sridhar Kumar, M. P.,Viswanathan, B.,Swamy, C. S.,Srinivasan, V.
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- Nor-statine and nor-cyclostatine polypeptides
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Polypeptides and derivatives thereof containing nor-statine and nor-cyclostatine are useful for inhibiting the angiotensinogen-cleaving action of the enzyme renin.
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- OXIDATIVE CLEAVAGE OF ALDO AND KETO OXIMES WITH CHROMYL CHLORIDE ADSORBED ON SILICA AND BENTONITE EARTH
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A number of Aldo, Keto and O-Acetyl oximes have been deblocked using chemisorbed Chromyl chloride on Bentonite and Silica Gel.A comparative study between the Chromyl chloride in solution and supported is also given.
- Salmon, Manuel,Miranda, Rene,Angeles, Enrique
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p. 1827 - 1832
(2007/10/02)
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- Oxidation of Primary and Secondary Alcohols by the Catalysis of Palladium
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Saturated and unsaturated alcohols are oxidized to the corresponding ketones in good or excellent yields by using an aryl halide (phenyl bromide or mesityl bromide) as an oxidant and palladium(0) or -(II) as a catalyst (0.6-3 mol percent relative to the alcohol) in the presence of a base (NaH or K2CO3).The similar oxidation of primary alcohols provides the corresponding aldehydes and/or esters.The aldehyde/ester selectivity is correlated to the steric and electronic features of substrates.The procedure is applied to the oxidation of 1-primary,ω-primary diols to lactones.
- Tamaru, Yoshinao,Yamada, Yoshimi,Inoue, Kenji,Yamamoto, Youichi,Yoshida, Zen-ichi
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p. 1286 - 1292
(2007/10/02)
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- Electrochemical Oxidation of Hydrazones
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Anodic oxidation of keto-arylhydrazones produced the parent ketone while a cyclic hydrazone yielded a rearranged product.
- Lin, En-Chu,Mark, Michael R. Van De
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p. 1176 - 1178
(2007/10/02)
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- A NOVEL SYNTHESIS OF SYMMETRIC KETONES BY THE REACTION OF ORGANOBORANES WITH CATECHOL DICHLOROMETHYLENE ETHER IN THE PRESENCE OF METHYLLITHIUM
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Organoboranes readily available from alkenes via hydroboration react with catechol dichloromethylene ether in the presence of methyllithium followed by the usual alkaline hydrogen peroxide oxidation to give corresponding symmetric ketones in good yields.
- Kawaguchi, Taihei,Ishidoya, Masahiro,Suzuki, Akira
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p. 113 - 116
(2007/10/02)
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