108-10-1

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.

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.

-

A new synthetic procedure for the selective reduction of α,β-unsaturated ketones and nitriles, using iodotrichlorosilane (ITCS generated in situ from SiCl4-NaI) under mild conditions to produce the corresponding saturated ketone and nitrile compounds in quantitative yields, is described.

Ketoximes are converted to the parent ketones in good yields when treated with potassium permanganate supported on neutral alumina (ASPP). An optimized procedure has been developed, the simple work-up minimizes loss of product and oximes have been selectively oxidized in the presence of alkenes.

-

The products of the gas-phase reactions of the OH radical with 2,4- dimethyl-2-pentanol and 3,5-dimethyl-3-hexanol in the presence of NO(x) have been determined at atmospheric pressure of air and 296 ± 2 K to assess the occurrence and importance of alkoxy radical isomerization. The products identified and quantified and their formation yields were as follows: from 2,4-dimethyl-2-pentanol: acetone, 0.92 ± 0.15; 2-methylpropanal, 0.209 ± 0.022; 4-methyl-2-2-pentanone, 0.046 ± 0.008; and 4-hydroxy-4-methyl-2- pentanone, 0.116 ± 0.018; from 3,5-dimethyl-3-hexanol: acetone, 0.120 ± 0.029; 2-butanone, 0.275 ± 0.021; 2-methylpropanal, 0.169 ± 0.016; 4- methyl-2-pentanone, 0.161 ± 0.012; and 4-hydroxy-4-methyl-2-pentanone, 0.250 ± 0.023. The observed formation of 4-hydroxy-4-methyl-2-pentanone provides conclusive evidence for the occurrence of isomerization of the alkoxy radicals (CH3)2C(OH)CH2C(O)(CH3)2 and CH3CH2C(CH3)(OH)CH2C(O)(CH3)2 via 1,5-H shifts. The reaction mechanisms are discussed, and isomerization rate constants for 1,5-H-atom abstraction from the -CH3 and -CH2- groups in the RCH2C(CH3)(OH)- CH2C(O)(CH3)2 alkoxy radicals (R = H and CH3) are derived.

-

50% Ethanolic or aqueous formic acid has been found to be extremely efficacious for the regeneration of aliphatic and aromatic ketones from phenylhydrazones.

We have investigated the regiochemistry of the stoichiometric and catalytic hydroamination of disubstituted alkynes by imidozirconium complexes. The addition of alkynes to Cp2Zr=NR occurred regioselectively to give metallacycles 2, with the larger alkyne substituent RL located α to the metal center. Hydrolysis of the metallacycles then gave enamines and their tautomeric imines which were the net result of anti-Markovnikov addition to the alkyne. The size of the R group on the imido ligand and the size of the alkyne were influential in determining the degree of regioselectivity. By utilizing Cp2(THF)Zr=NR to generate Cp2Zr=NR at room temperature and Cp2Zr(R′)(NHR) to generate Cp2Zr=NR at high temperature, it was determined that the thermodynamic and kinetic regioselectivities were nearly identical for dialkylacetylenes. In contrast, for 1-phenylpropyne, the thermodynamic regioselectivity was found to be greater than the kinetic regioselectivity. The regioselectivity was found to be invariant from -6 to 45°C in the addition of both 4-methyl-2-pentyne and 2-hexyne to Cp2(THF)Zr=NAr. However, a significant erosion of regioselectivity was observed when 2-hexyne and 4-methyl-2-pentyne were catalytically hydroaminated by Cp2Zr(NHAr)2 at 120°C. A kinetic study of the catalytic reaction suggested that the reason for this erosion was that the protonation step in the catalytic cycle (k3[amine]) was slower than the cycloreversion of the stereoisomeric metallacycles to alkyne and Cp2Zr=NAr (k-2) (the step that leads to regioequilibration). Because the protonation is selective for the metallacycle in which the smaller substituent is located at the position adjacent to the metal center, it counters the regioselectivity of the cycloaddition. This was an unexpected result because (1) an earlier study showed that k3 [amine] was larger than k-2 for the addition of diphenylacetylene to Cp2Zr=NR at both 25°C and the catalytic reaction temperature (95°C in this case) and (2) in the present work, it was demonstrated that k3 [amine] was also larger than k-2 for dialkylacetylenes at 25°C. It was concluded that the relative magnitudes of the rate constants k3 (protonation) and k-2 (reversion) must vary with temperature more dramatically in the dialkylacetylene + Cp2Zr=NR reaction than in the diarylacetylene + Cp2Zr=NR reaction. This was confirmed by direct competition experiments carried out at 25, 60, and 100°C. We believe that the cycloreversion step k-2 is characterized by both a larger ΔH? and a larger ΔS? than protonation because the former is a unimolecular and the latter a bimolecular reaction.

Lanthanum and cerium oxides have been tested for the title reaction at 623 K and atmospheric pressure in a flow reactor. Lanthanum oxide (prepared from the corresponding nitrate) gives mainly 4-methylpent-1-ene (80% of the products). Similar results are observed with cerium oxide obtained from the corresponding hydroxide, whereas cerium oxide prepared from nitrate is less selective towards alk-1-enes. In addition to dehydration, dehydrogenation to 4-methylpentan-2-one is also observed to a limited extent for all the catalysts. Information on the acid-base properties of the samples was obtained by adsorption microcalorimetry of ammonia and carbon dioxide and correlated to reaction selectivities. Possible changes in the oxidation state of cerium ions due to the reaction atmosphere are considered. The present results are compared with former data for zirconia catalysts. Modification of cerium oxide via immersion in NaOH solution does not appear to be useful for improving alk-1-ene selectivity.

The synthesis of methyl isobutyl ketone (MIBK) can be carried out by the condensation of acetone in the presence of hydrogen over a supported metal catalyst. Previous studies have shown that hydroxyapatite is an excellent catalyst for condensation reactions. The present investigation was undertaken in order to elucidate the reaction mechanism and site requirements for acetone coupling to MIBK over a physical mixture of hydroxyapatite and Pd/SiO2. The reaction is found to proceed by consecutive aldol addition to form diacetone alcohol (DAA), dehydration of DAA to mesityl oxide (MO), and hydrogenation of MO to MIBK. The products formed by feeding DAA and MO reveal that aldol addition of acetone is rapid and reversible, and that the subsequent dehydration of DAA is rate-limiting. Pyridine and CO2 titration show that aldol dehydration occurs over basic sites via an E1cB mechanism. A series of cation-substituted hydroxyapatite samples were prepared by ion-exchange to further investigate the role of acid-base strength on catalyst performance. Characterization of these samples by PXRD, BET, ICP-OES, XPS, CO2-TPD, and Raman spectroscopy demonstrated that the exchange procedure used does not affect the bulk properties of hydroxyapatite. DFT calculations reveal that in addition to affecting the Lewis acidity/basicity of the support, the size of the cation plays a significant role in the chemistry: cations that are too large (Ba2+) or too small (Mg2+) adversely affect reaction rates due to excessive stabilization of intermediate species. Strontium-exchanged hydroxyapatite was found to be the most active catalyst because it promoted α-hydrogen abstraction and C–O bond cleavage of DAA efficiently.

-

-

-

-

-

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).

-

[(PPh3)2Ru(CH3CN)3Cl][BPh4] has been found to catalyze the selective reduction of double bonds in α,β-unsaturated ketones with high conversions when formic acid is the hydrogen donor.

We report here an efficient bifunctional catalyst of TiO2 coating and supported Pd on cordierite (T500/Cor&Pd/Cor) for one-pot synthesis of MIBK from acetone. The obtained 75% MIBK selectivity at 60% acetone conversion was the best performance ever reported for metal oxide based catalyst, without obvious deactivation for at least 12 h on stream. The superior performance of T500/Cor&Pd/Cor could be attributed to the dominant base sites and moderate acid sites on TiO2 coating caused by the nanoscale anatase crystallite, and its combination style of being physically mixed with Pd.

-

Pd-doped propyl sulfonic acid-functionalized hollow nanospheres proved to be efficient bifunctionalized catalysts for the one-pot synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen in liquid phase. These hollow nanospheres exhibited a higher activity than their bulk mesoporous counterparts (SBA-15 or FDU-12), mainly due to the short diffusion resistance of hollow nanospheres. Hollow nanospheres with silica frameworks showed higher activity and selectivity for MIBK than those with ethane-bridged frameworks, suggesting that hollow nanospheres with hydrophilic surface properties favor the formation of MIBK. This is probably due to the increased affinity of the hydrophilic surface towards acetone and its decreased affinity towards MIBK, which precludes deep condensation of MIBK with acetone. Under optimal conditions, up to 90 % selectivity for MIBK can be obtained with conversions of acetone as high as 43 %. This result is among the best reported so far for mesoporous silica-based catalysts. The control/fine-tuning of morphology and surface properties provides an efficient strategy for improving the catalytic performance of solid catalysts.

The iridium complex > formed by intramolecular C-H oxidative addition, as shown by X-ray analysis, behaves as a chemoselective catalyst in hydrogen transfer reduction of α,β-unsaturated ketones to unsaturated alcohols.

The one-step MIBK synthesis from 2-propanol was investigated as an alternative process to current conventional technology that produces MIBK from acetone. The reaction was studied at 473 K and atmospheric pressure using bifunctional Cu-base catalysts. Single MIOx, binary MIMIIOx, and Cu-containing CuMI(MII)Ox mixed oxides, where MI and MII are metal cations such as Mg2+, Al3+, or Ce3+, were obtained by thermal decomposition of precipitated precursors. The density and strength of surface basic sites were obtained by CO2 chemisorption and by temperature-programmed desorption (TPD) of CO2, whereas the acid site densities were measured by TPD of NH3. The MIBK synthesis reaction network involves consecutively the initial 2-propanol dehydrogenation to acetone, the aldol condensation of acetone to mesityl oxide, and the final hydrogenation of this compound to MIBK. Cu/SiO2 promoted 2-propanol dehydrogenation to acetone but did not form any C6 condensation products. When copper was supported on protonic HY zeolite, 2-propanol was essentially dehydrated to propylene and the formation of acetone was negligible. Bifunctional Cu-base catalysts were active and selective for MIBK synthesis. The highest MIBK formation rates were obtained on Cu-base solids containing a high density of medium-strength Bronsted base-weak Lewis acid pair sites for promoting the acetone aldol condensation step. CuMg10Al7Ox was the best catalyst because it contained in intimate contact highly dispersed Cu0 crystallites with proper Al3+ Lewis sites and Mg+2-O2- basic pairs and efficiently combines the active sites required for consecutive reactions leading to MIBK. Catalysts containing strongly basic O2- sites, such as CuMg10Ox and CuMg10Ce2Ox, presented lower condensation rates because isolated O2- hindered stabilization of anionic intermediates for acetone condensation. The effect that the reacting atmosphere (N2 or H2) has on catalyst activity and selectivity was investigated on CuMg10Al7Ox. It was found that the catalyst activity is enhanced in N2, but for a given 2-propanol conversion the selectivity for C6 aldol condensation products is higher in hydrogen. MIBK yields as high as 25% were achieved in comparison to the 30% typically obtained in current commercial high-pressure processes from acetone.

A bimolecular rate constant, κDHO, of (29 ± 9) × 10-12 cm3 molecule-1 s-1 was measured using the relative rate technique for the reaction of the hydroxyl radical (OH) with 3,5-dimethyl-1-hexyn-3-ol (DHO, HC≡CC(OH)(CH3)CH2CH(CH3 2) at (297 ± 3) K and 1 atm total pressure. To more clearly define DHO's indoor environment degradation mechanism, the products of the DHO + OH reaction were also investigated. The positively identified DHO/OH reaction products were acetone ((CH3 2C=O), 3-butyne-2-one (3B2O, HC≡CC(=O)(CH3)), 2-methyl-propanal (2MP, H(O=)CCH(CH3)2), 4-methyl-2-pentanone (MIBK, CH3C(=O CH2 CH(CH3)2), ethanedial (GLY, HC(=O C(=O)H), 2-oxopropanal (MGLY, CH3C(=O)C(=O)H), and 2,3-butanedione (23BD, CH3C(=O)C(=O)CH3). The yields of 3B2O and MIBK from the DHO/OH reaction were (8.4 ± 0.3) and (26 ± 2)%, respectively. The use of derivatizing agents O-(2,3,4,5,6-pentalfluorobenzyl)hydroxylamine (PFBHA) and N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible DHO/OH reaction mechanisms based on previously published volatile organic compound/OH gas-phase reaction mechanisms.

-

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.

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.

Oximes are converted to the parent carbonyl compounds in good yields when treated with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) (1). An optimized procedure has been developed; the simple work-up minimizes loss of product and oximes have been selectively oxidized in the presence of alcohols and alkenes.

-

CuI catalyses an efficient conjugate reduction of α,β-unsaturated carbonyl compounds by LiAlH4 in the presence of hexamethylphosphoric triamide at -78 degC.

-

A simple procedure for a clean and high-yielding oxidative deoximation of benzaldoximes and ketoximes using a silica-gel-supported chromic acid reagent has been developed. This solid-supported reagent allows us to carry out this reaction in nonaqueous dichloromethane reaction media. Copyright Taylor & Francis Group, LLC.

-

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.

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.

-

Dilithio acetoacetate, which can be generated from acetoacetic acid and n-butyllithium, undergoes alkylation followed by facile decarboxylation to give methyl ketones.

Activated nickel, produced by the ultrasound-promoted reduction of nickel iodide with lithium, catalyzes the 1,4 addition of phenylsilane to α, β-unsaturated ketones and α, β-unsaturated nitriles to give, after hydrolysis, high yields of the products of 1, 2 hydrogenation.

A new catalytic system for oxidation of alcohols with oxygen by N-hydroxyphthalimide (NHPI) combined with CuBr has been developed. The reaction results showed that this catalytic system can effectively catalyze the oxidation of alcohols to the corresponding carboxylic acids or ketones. We obtained 100% selectivity for acetophenone at 94.2% conversion of phenylethanol at 75 °C for 20 h. A mechanism of oxidation of alcohols catalyzed by NHPI/CuBr was proposed. Springer Science+Business Media B.V. 2011.

3,3,5-Trimethylcyclohexanone (TMCH) is an important pharmaceutical intermediate and organic solvent, which has important industrial significance. The selective hydrogenation of isophorone was studied over noble metal (Pd/C, Pt/C, Ir/C, Ru/C, Pd/SiO2, Pt/SiO2, Ir/SiO2, Ru/SiO2), and non-noble metal (RANEY Ni, RANEY Co, RANEY Cu, RANEY Fe, Ni/SiO2, Co/SiO2, Cu/SiO2, Fe/SiO2) catalysts and using solvent-free and solvent based synthesis. The results show that the solvent has an important effect on the selectivity of TMCH. The selective hydrogenation of isophorone to TMCH can be influenced by the tetrahydrofuran solvent. The conversion of isophorone is 100%, and the yield of 3,3,5-trimethylcyclohexanone is 98.1% under RANEY Ni and THF. The method was applied to the selective hydrogenation of isopropylidene acetone, benzylidene acetone and 6-methyl-5-ene-2-heptanone. The structures of the hydrogenation product target (4-methylpentan-2-one, 4-benzylbutan-2-one and 6-methyl-heptane-2-one) were characterized using 1H-NMR and 13C-NMR. The yields of 4-methylpentan-2-one, 4-benzylbutan-2-one and 6-methyl-heptane-2-one were 97.2%, 98.5% and 98.2%, respectively. The production cost can be reduced by using RANEY metal instead of noble metal palladium. This method has good application prospects. This journal is

-

Silica-supported polyamidoamine (PAMAM) dendrimers with different spacer lengths were prepared. After the introduction of diphenylphosphino groups, complexation to dibenzylidenepalladium(0) gave the desired silica-supported dendrimer - palladium catalyst complexes G0 to G4-C2-Pd. These catalysts showed activity towards the oxidation of terminal alkenes to methyl ketones. A dependence of catalytic activity on the spacer length of the diamine in PAMAM was observed.

Selective hydrogenation of 2-cyclohexen-1-one over Pt-MCM-41 proceeds at a very high rate and produces cyclohexanone with selectivity of 100% in a batch reactor; a marked increase in the reaction rate (TOF) from 2283 min-1 to 5051 min-1 is observed on increasing the pressure from 7 MPa to 14 MPa at 40°C. The Royal Society of Chemistry 2009.

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.

-

The ability to successfully incorporate heterogeneous catalysts into chip-microreactors is demonstrated in the application of a Pd/ZSM-5 and Pd/silicalite chip-based microreactor for the synthesis of methyl-iso-ketone (MIBK) and the hydrogenation of 3-methyl-1-pentyn-3-ol. The bifunctional Pd/ZSM-5 chip-microreactor provides a high selectivity (>90%) to MIBK due to the incorporation of palladium and high Br?nsted acidity while demonstrating the ability to regenerate and reuse the Pd/ZSM-5 chip-microreactor. The Pd/silicalite chip-microreactor illustrated the advantage of improved control of residence time in the microreactor to obtain high alkene yields. In addition, the design of chip-holders which are operable at high temperature, pressure and have a high chemical resistance further extend the operability of chip-based microreactors for use in the special chemical industry.

Treatment of thioacetals and thioketals with iodosobenzene in anhydrous DCM conveniently afforded the corresponding carbonyl compounds in high yields under water-free conditions. The mechanistic studies indicate that this dethioacetalization/dethioketalization process does not need water and the oxygen of the carbonyl products comes from the hypervalent iodine reagent.

Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.

The treatment of α,β-unsaturated carbonyl compounds and 1,3-diketones with Raney Ni-Al alloy in aqueous media yielded as major reaction products the corresponding saturated alcohols and/or the corresponding hydrocarbons, in a complete transformation of the starting material.

Methyl isobutyl ketone (MIBK) is an α, β-unsaturated carbonyl compound, which is often used as solvent and extractor for antibiotics in the pharmaceutical industry. One alternative to the synthesis of MIBK from mesityl oxide (MO) is through catalytic transfer hydrogenation (CTH) using various organic compounds as hydrogen donors in the presence of a catalyst. The purpose of this study was to synthesize MIBK from MO through the CTH reaction using sodium formate as the hydrogen donor and as the catalyst, Pd nanoparticles were used and deposited on the activated charcoal (Pd-NP/AC). Based on the Gas Chromatography-Mass spectrometer (GC-MS) analysis, the conversion value of MO was obtained in 97.3% and the yield of the MIBK formation was 10.5%. Meanwhile, the highest selectivity was obtained in 17% at 40° C. The results show that sodium formate can effectively be used to reduce MO into MIBK in the presence of Pd-NP/AC catalyst at 70° C for 5 hours.

Two highly efficient metal-organic framework catalysts TJU-68-NHPI and TJU-68-NDHPI have been successfully synthesized through solvothermal reactions of which the frameworks are merged with N-hydroxyphthalimide (NHPI) units, resulting in the decoration of pore surfaces with highly active nitroxyl catalytic sites. When t-butyl nitrite (TBN) is used as co-catalyst, the as-synthesized MOFs are demonstrated to be highly efficient and recyclable catalysts for a novel three-phase heterogeneous oxidation of activated C?H bond of primary and secondary alcohols, and benzyl compounds under mild conditions. Based on the high efficiency and selectivity, an environmentally benign system with good sustainability, mild conditions, simple work-up procedure has been established for practical oxidation of a wide range of substrates.

Selective oxidation of C(sp3)-H bonds to carbonyl groups by abstracting H with a photoinduced highly active oxygen radical is an effective method used to give high value products. Here, we report a heterogeneous photocatalytic alkanes C-H bonds oxidation method under the irradiation of visible light (λ= 425 nm) at ambient temperature using an anion-cation dual-metal-site modulated carbon nitride. The optimized cation (C) of Fe3+or Ni2+, with an anion (A) of phosphotungstate (PW123?) constitutes the nanoscale dual-metal-site (DMS). With a Fe-PW12dual-metal-site as a model (FePW), we demonstrate a A-C DMS nanoscale localized carbon nitride (A-C/g-C3N4) exhibiting a highly enhanced photocatalytic activity with a high product yield (86% conversion), selectivity (up to 99%), and a wide functional group tolerance (52 examples). The carbon nitride performs the roles of both the visible light response, and improves the selectivity for the oxidation of C(sp3)-H bonds to carbonyl groups, along with the function of A-C DMS in promoting product yield. Mechanistic studies indicate that this reaction follows a radical pathway catalyzed by a photogenerated electron and hole on A-C/g-C3N4that is mediated by thetBuO˙ andtBuOO˙ radicals. Notably, a 10 g scale reaction was successfully achieved for alkane photocatalytic oxidation to the corresponding product with a good yield (80% conversion), and high selectivity (95%) under natural sunlight at ambient temperature. In addition, this A-C/g-C3N4photocatalyst is highly robust and can be reused at least six times and the activity is maintained.

Herein we describe a general, mild, and scalable method for hydrodeoxygenation of readily accessible tertiary alkyl oxalates by Zn/silane under Ni-catalyzed conditions. The reduction method is suitable for an array of structural motifs derived from tertiary alcohols that bear diverse functional groups, including the synthesis of a key intermediate en route to estrone.

SOLUTION: A method of producing a terminal double bond-containing compound includes: reacting a compound represented by the following general formula (I) under a pressure of 0 MPa-G or lower in the presence of a metal oxide catalyst to produce a terminal double bond-containing compound represented by the following general formula (II). In formula (I) and formula (II), R1 and R2 represent hydrocarbon groups, and R1 and R2 may bond each other to form a ring together with carbon atoms by which R1 and R2 bond. EFFECT: According to the present invention, a terminal double bond-containing compound can be safely and easily produced with high selectivity. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT

The one-pot synthesis of methyl isobutyl ketone (MIBK) and methyl isobutyl methanol (MIBC) from acetone and hydrogen is a typical cascade reaction comprised of aldol condensation-dehydration-hydrogenation. Pd loss and aggregation during long term operation are typical problems in industrial application. In this paper, an active and stable catalyst was achieved with defective UiO-66 as a support for Pd, which was synthesized with the ratio 15?:?1 of ZrOCl2·8H2O to ZrCl4as Zr-precursors. The resultant Pd catalyst remained active for at least 1000 h with a MIBK + MIBC selectivity of 84.87-93.09% and acetone conversion of 45.26-53.22% in a continuous trickle-bed reactor. Besides the increased Br?nsted acid amount generated by the defect sites was favorable for the activity, the cavity confinement in the UiO-66 (R= 15?:?1) structure also efficiently prevented Pd loss and aggregation during the long term run. The contrast of the characterization of the fresh and used Pd/UiO-66 (R= 15?:?1) indicated that the deactivation of the catalyst was attributed to carbonaceous accumulation on the catalyst surface, which could be easily regenerated by calcination. This work supplied a new alternative for the design and utilization of industrial catalysts for MIBK and MIBC synthesis.

The treatment of α,β-unsaturated carbonyl compounds and 1,3-diketones with Raney Ni-Al alloy in aqueous media yielded as major reaction products the corresponding saturated alcohols and/or the corresponding hydrocarbons, in a complete transformation of the starting material.

We report a platinum nanocluster/graphitic carbon nitride (Pt/g-C3N4) composite solid catalyst with a photocatalytic anaerobic oxidation function for highly active and selective transformation of alcohols to ketones. The desirable products were successfully obtained in good to excellent yields from various functionalized alcohols at room temperature, including unactivated alcohols. Mechanistic studies indicated that the reaction could proceed through a Pt-mediated hole oxidation initiating an α-alcohol radical intermediate followed by a two-electron oxidation pathway. The merit of this strategy offers a general approach towards green and sustainable organic synthetic chemistry.

A novel catalytic system including NiCl2-NHC ligand precursor has been developed for the preparation of imines from amines and ketones from alcohols. Owing to the acceptorless dehydrogenation pathway for this reaction, the hydrogen gas is liberated as a by-product. The active catalyst is generated in situ by the reaction of nickel (II) chloride, bis (imidazolium) chlorides and potassium tert-butoxide. The products were obtained in good to excellent yields and a wide variety of amines and ketones were applied successfully in this protocol.

The development of an anti-Markovnikov Wacker-type oxidation for simple aliphatic alkenes is a significant challenge. Herein, a variety of aldehydes can be selectively obtained from various unbiased aliphatic terminal alkenes using PdCl2(MeCN)2/CuCl in the presence of p-benzoquinone (BQ) under mild reaction conditions. Isomerization of the terminal alkene to the internal alkene was suppressed via slow addition of the starting material to the reaction mixture. In addition to the Pd catalyst, CuCl and BQ were essential in order to obtain the anti-Markovnikov product with high selectivity. Terminal alkenes bearing a halogen substituent afforded their corresponding aldehydes with high anti-Markovnikov selectivity. The halogen acts as a directing group in the reaction. DFT calculations indicate that a μ-chloro Pd(II)?Cu(I) bimetallic species with BQ coordinated to Cu is the catalytically active species in the case of a terminal alkene without a directing group.

Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.

We demonstrate the selective oxidation of secondary alcohols and activated primary alcohols to their corresponding aldehydes or ketones using Fe-bTAML as the catalyst and sodium hypochlorite (NaClO) as the oxidant. Good to excellent yields of 80%–99% for the carbonyl compounds and turnover numbers up to ～500 was obtained with this catalytic system. The reactions are clean, performed under mild conditions (air, room temperature) and yielded sodium chloride as the only by-product. The yield and turnover number were dependent on the pH of the reaction and this difference was attributed to the different reactive intermediates that was formed at pH 7 and pH 12 (FeV(O) and FeIV(O) respectively). Reactions involving the FeV(O) intermediate oxidize secondary alcohols more efficiently than its FeIV(O) analog. This trend was reversed for the oxidation of activated primary alcohols where reactions involving FeIV(O) afforded much higher TON's. This reactivity trend can be explained from the differences in bond dissociation energy (BDE) of their corresponding one electron reduced species ([FeIV-OH], ～99 kcal/mol; [FeIII-OH], ～83 kcal/mol) as well as their relative stabilities in the solvent during reaction. This catalytic system was found to be unsuitable for nonconjugated primary alcohol due to the formation of the inactive FeIV(OMe) intermediate after one catalytic cycle.

Although photoredox catalysis employing Ru(ii) and Ir(iii) complexes as photocatalysts has emerged as a versatile tool for oxidative C-H functionalization under mild conditions, the need for additional reagents acting as electron donor/scavenger for completing the catalytic cycle undermines the practicability of this approach. Herein we demonstrate that photo-induced oxidative C-H functionalization can be catalysed with high product yields under oxygen-free and acceptorless conditions via inner-sphere atom abstraction by binuclear platinum(ii) diphosphite complexes. Both alcohols (51 examples), particularly the aliphatic ones, and saturated N-heterocycles (24 examples) can be efficiently dehydrogenated under light irradiation at room temperature. Regeneration of the photocatalyst by means of reductive elimination of dihydrogen from the in situ formed platinum(iii)-hydride species represents an alternative paradigm to the current approach in photoredox catalysis.

Terminal acetals were selectively synthesized from various unbiased aliphatic terminal alkenes and 1,2-, 1,3-, or 1,4-diols using a PdCl2(MeCN)2/CuCl catalyst system in the presence of p-toluquinone under 1 atm of O2 and mild reaction conditions. The slow addition of terminal alkenes suppressed the isomerization to internal alkenes successfully. Electron-deficient cyclic alkenes, such as p-toluquinone, were key additives to enhance the catalytic activity and the anti-Markovnikov selectivity. The halogen groups in the alkenes were found to operate as directing groups, suppressing isomerization and increasing the selectivity efficiently.

The one-pot synthesis of methyl isobutyl ketone (MIBK) from acetone using multifunctional catalysts is an important sustainable organic synthesis method with high atom and energy efficiency. Herein. we report a series of Pd supported on mixed metal oxide (MMO) catalysts with controllable acidic/basic/metallic sites on the surface. We study the relationship between the nature, synergy, and proximity of active sites and the catalytic performance of the multifunctional catalyst in the tandem reaction, in detail. In the existence of Lewis acid and base sites, the catalysts with medium-strength acidic/basic sites show preferred activity and/or MIBK selectivity. For multifunctional catalysts, the catalytic properties are more than just a collection of active sites, and the Pd/Mg3Al-MMO catalyst possessing 0.1% Pd loading and ~0.4 acid/base molar ratio exhibits the optimal 42.1% acetone conversion and 37.2% MIBK yield, which is among the best reported so far for this tandem reaction under similar conditions. Moreover, the proximity test indicates that the intimate distance between acidic/basic/metallic sites can greatly shorten the diffusion time of the intermediate species from each active site, leading to an enhancement in the catalytic performance.

A process for producing methyl isobutyl ketone from acetone comprising the following steps: - feeding to a first continuous reactor (101, 201) a stream of hydrogen and a stream consisting of fresh dimethyl ketone, unconverted dimethyl ketone recirculated by a recovery section and a liquid stream effluent from a second reactor in series with the first reactor; - feeding to a second continuous reactor (102, 202) a gas stream rich in hydrogen and effluent from the first reactor, and a liquid stream consisting of fresh dimethyl ketone and a fraction of the unconverted dimethyl ketone recirculated from the recovery section; - feeding the liquid phase produced in the first reactor tothe dimethyl ketone recovery section; - separating the unconverted dimethyl ketone, to be recycled to the first and second reactors, the methyl isobutyl ketone produced in the first and second reactors, by-products having boiling point lower than methyl isobutyl ketone and water from the current fed to the recovery section.

The synthesis of a functionalized supramolecular cavitand with inwardly oriented AuI and P=O moieties was explored, including its catalytic proclivity in the selective hydration of internal alkynes. The cavitand works as a supramolecular flask device: AuI coordinates to the triple bond, the P=O moiety connects with a H2O molecule, and the cavity favors folding of a single alkynyl side chain. Several tests of different substrate patterns indicated that the cavity was substrate specific, similar to enzymatic catalysis.

The effects of the catalytic cavities in gold-functionalized cavitands in the hydration of internal alkynes have been studied. Variations on cavitand structures revealed the importance of two features that were studied: (1) flanking aromatic rings, and (2) an adjacent P=O moiety. The di-quinoxaline-spanned resorcin[4]arene system provides a well-defined compartment, in which a cationic Au ion activates an internal alkyne for conversion into a ketone by delivery of water that has also been activated, this time by a P=O moiety. We synthesized four variations on our parent cavitand. Variations of the cavitand walls include replacement of quinoxaline components with pyrazine or methylene units. Variation of the P=O center was accomplished with methylene or quinoxaline moieties. All variants displayed lower catalytic activity or selectivity, allowing us to confirm the significance both of an internal cavity and of an activation site for water.

An iron-catalyzed chemo- and diastereoselective reduction of α,β-unsaturated ketones into the corresponding saturated ketones in mild reaction conditions is reported herein. DFT calculations and experimental work underline that transfer hydride reduction is a more facile process than hydrogenation, unveiling the fundamental role of the base.

An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH2Cl2/NaHCO3 (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.

The NADPH-dependent secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (TeSADH), displaying broad substrate specificity and low enantioselectivity, was engineered to accept NADH as a cofactor. The engineered TeSADH showed a >10 000-fold switch from NADPH towards NADH compared to the wildtype enzyme. This TeSADH variant was applied to a biocatalytic hydrogen-borrowing system that employed catalytic amounts of NAD+, ammonia, and an amine dehydrogenase, which thereby enabled the conversion a range of alcohols into chiral amines.

The present invention relates to a process for the one-pot hydrogenation and dehydration or isomerization of an organic compound, and to a catalyst composition for this process comprising transition metal particles having particle size below 50 nm supported on a material comprising at least one fluorinated polymer (P), wherein polymer (P) bears -SO2X functional groups, X being selected from X' and OM, X' being selected from the groups consisting of F, CI, Br and I; and M being selected from the group consisting of H, and alkaline metal and NH4.

The invention provides a production process of methyl isobutyl ketone. The production process includes the following steps that a, hydrogen is conveyed into a water mist catcher for water removal; b, hydrogen and acetone are mixed and conveyed into a reactor to react, an adopted catalyst is strong acid positive ion exchange resin treated through palladium acetate, a reaction product is subjected to water removal again through hydrogen obtained after condensation separation and reused in the reactor for the reaction; c, alkali is added to a condensation product solution; d, the product solution to which alkali is added enters an acetone light-component tower to be separated, a solution produced from the bottom of the tower enters an acetone recovery tower for rectification, negative pressure operation is conducted in the acetone recovery tower, acetone produced from the top of the tower is reused in a fixed bed reactor, coarse MIBK produced from the bottom of the tower enters a phase separator; e, the coarse MIBK enters an MIBK light-component tower for rectification, heavy components produced from the bottom of the tower enter a finished MIBK tower for rectification, and finished MIBK is produced from the lateral line of the finished MIBK tower. Thus, energy utilization is greatly reduced, and meanwhile safe and efficient production can be facilitated while the utilization rate of original raw materials is guaranteed.

The invention discloses a preparation method for synthesis of methyl isobutyl ketone and methyl isobutyl alcohol. The acetone and hydrogen are used as raw materials to synthesize methyl isobutyl ketone and methyl isobutyl alcohol at the reaction temperature of 150-250 DEG C; in the reaction process, Pd/MyOx is used as a catalyst at atmospheric pressure state, the mole ratio of the hydrogen to the acetone is 50:1 to 3: 1, and the volume velocity of the hydrogen is 800-10000h; the Pd/MyOx is that the amphoteric metal oxide MyOx with baking temperature not higher than 600 DEG C is used as a carrier to load the Pd, x and y in the MyOx are respectively 1, 2 or 3, and M is selected from polyvalent metal in IVB-VIIB family elements, and is in corresponding high valence in the MyOx. The method is applied to the atmospheric pressure gas phase reaction for synthesizing methyl isobutyl ketone and methyl isobutyl alcohol through acetone hydrogenation, the highest conversion rate of the acetone can achieve 62.6%, the highest selectivity of the methyl isobutyl ketone and methyl isobutyl alcohol can achieve 93.2%, and the methyl isobutyl alcohol accounts for 1/3. Compared with the similar catalyst, the catalyst disclosed by the invention is not only simple in preparation method and low in cost, but also obviously improves the selectivity of the methyl isobutyl ketone and methyl isobutyl alcohol.

Nanoparticles (NPs) of Pd and Pt were used for the selective oxidation of aliphatic alcohols with molecular oxygen as an oxidant at near ambient temperatures under visible light irradiation. Distinct final products were obtained under identical reaction conditions, aliphatic esters formed over the Pd NPs while aldehydes formed over the Pt NPs. The reason for this different product selectivity is proven to be due to the much stronger interaction of Pd NPs with alcohol and aldehyde compared to Pt NPs. The photocatalytic activity is tuneable by light intensity or a moderate change in the reaction temperature.

Here we report a class of photocatalysts: mixed-valence vanadium oxide particles grafted onto a variety of oxide supports. In these catalysts V6O13 species with mixed oxidation states (V4+ or V5+) are believed to be catalytically active sites. These catalysts successfully enable alcohol oxidation to selectively produce aldehydes and ketones using O2 as the oxidant. The catalytic process is driven by visible light irradiation at room temperature and, most importantly, progresses with negligible overoxidation. The catalysts can even selectively oxidize aliphatic alcohols, which are much more challenging to control in comparison to aromatic analogues. They can also be applied to the activation and oxidation of the otherwise stable C-H bonds of saturated aromatic hydrocarbons, such as toluene and xylene, under irradiation. Both experimental results and density functional theory (DFT) simulations suggest the formation of V6O13-alkoxide species as the initial step in the catalytic cycle. The V6O13-alkoxide then acts as the light harvester, being excited by light of wavelength shorter than 550 nm. Facile room-temperature C-H bond cleavage in the excited state V6O13-alkoxide in the presence of O2 leads to the carbonyl-containing products. These findings demonstrate an example of light-driven selective oxidation of diverse alcohols via in situ formation of photoresponsive V6O13-alkoxide species. This catalytic process is especially valuable for the synthesis of temperature-sensitive products and represents an alternative pathway to many conventional thermal oxidation reactions.

We previously reported that the iminopyridine iron(II) complex 1, easily and quantitatively obtainable in situ, can activate H2O2 to form a powerful oxidant, capable of aliphatic C-H bond hydroxylation. In the present study we expand the application of this catalyst to the oxidation of a series of alcohols to the corresponding carbonyl compounds. The oxidation of aliphatic alcohols proceeds smoothly, while that of benzylic alcohols is shown to be challenging. Some collected pieces of evidence suggest a preference of the oxidizing species for the aromatic ring instead for the alcoholic moiety. The decrease of the electron density in the aromatic ring shifts the oxidation from the aromatic towards the alcoholic moiety. Quite surprisingly, preferential oxidation of cyclohexanol versus benzylic alcohol was achieved, showing unprecedented selectivity.

The present invention relates to an organic matter synthesis method, particularly to a novel methyl heptanone synthesis method, wherein isovaleraldehyde and acetone are adopted as raw materials and are subjected to an aldol condensation reaction and a hydrogenation reaction through a one-pot method under catalysis of catalysts such as triethylamine and palladium carbon to synthesize the methyl heptanone, a small amount of the by-product methyl isobutyl ketone is subjected to distillation recovery, the recovered product is supplied for other positions, and the catalyst used in the reaction process can be repeatedly applied after being recovered. According to the present invention, the method has characteristics of easy operation, high reaction yield, energy saving and environmental protection, and is suitable for industrial production.

The invention discloses a chemical synthetic method, specifically a method for synthesizing 2-heptanone by using acetone and butyraldehyde as raw materials. According to the invention, acetone and butyraldehyde which used as raw materials undergo a cross aldol condensation reaction under catalysis of solid base, and reaction products further undergo dehydration and catalytic hydrogenation so as to prepare 2-heptanone. The invention has advantages as follows: technological process is shortened by the technology; generation of an acid-containing waste liquid is avoided; generation of by-products is minimized; investment in equipment is reduced; and production costs of the product are decreased.

The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. The monodentate phosphoramidite ligand exhibits superb reactivity (TONs of up to 20 000) and enantioselectivity (up to 99 % ee). Additives played important roles in this reductive coupling reaction. Asymmetric reductive coupling of a ketone and an amine is a straightforward and atom-economic approach for preparing optically enriched amines. The highly efficient and direct asymmetric reductive amination of arylacetones, catalyzed by an iridium complex, supplies enantiomerically pure β-arylamines. The new phosphoramidite ligands reported show superb reactivity and enantioselectivity in this reductive coupling. M.S.=molecular sieves, TFA=trifluoroacetic acid.

Aiming at the valorisation of furfural-derived compounds, the hydrodeoxygenation of furfural-acetone condensation products has been studied using supported platinum catalysts. The influence of the catalytic properties of different supports, such as SiO2, Al2O3, TiO2, hydrotalcite (HTC), Beta zeolite, Al-SBA-15 and WO3-ZrO2, was evaluated in a batch reactor for 480 min at 200 °C and 50 bar of H2. The used feed consisted of a mixture of furfural-acetone adducts (C8-C19), obtained in previous experiments using a continuous flow reactor and hydrotalcite as a catalyst. Except for Pt/SiO2, all catalysts showed high conversion of the reactants, especially due to the hydrogenation of all the aliphatic CC bonds. However, the extent of further hydrogenation (furan CC and ketone CO bonds) was limited, particularly when HTC and Al2O3 were used as supports. The higher accessibility of Pt/TiO2 and the smaller Pt particle size shown by Pt/Al-SBA-15, Pt/WO3-ZrO2 and Pt/Beta in comparison with the other catalysts led to an improvement in the hydrogenation of furanic and ketonic groups, likely due to lower adsorption constraints. The higher acid character of the latter group of catalysts promotes dehydration and ring opening steps, thus enhancing the selectivity towards linear alcohols. Likewise, a significant increase in the extent of aldol condensation reactions was also observed with these catalysts, yielding longer carbon chain compounds. Based on this study, a reaction scheme for the transformation of 4-(2-furyl)-3-buten-2-one (C8) into octane has been proposed in order to establish a valuable correlation between the main conversion pathways and the catalytic properties of the employed heterogeneous catalyst, thus contributing to further development of efficient deoxygenation catalysts.

The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.

The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.

A novel trifunctional catalyst with basic, acidic and metal sites was synthesized by nanocolloidal method and used in industrially important reactions. in the laboratory. The synthesized catalyst consisted of palladium and hydrotalcite supported on transition metal modified hexagonal mesoporous silica (HMS) and was characterized in virgin and reused states using a number of techniques such as elemental analysis, FTIR, NH3- TPD, CO2- TPD, H2- TPR, XRD and BET surface area. The activity of particular catalytic site was engineered so that a desired reaction pathway was followed in spite of possibility of multiple series and parallel or complex reactions. One pot cascade engineered synthesis of ethyl benzyl acetoacetate from benzaldehyde and ethyl acetoacetate was studied in solvent free condition in a batch reactor. The effects of various parameters on the rates of reaction were analysed to establish instantaneous selectivity. Reaction mechanism and kinetic modelling was studied to validate the experimental results. The reaction follows Langmuir-Hinshelwood-Hougen-Watson mechanism involving weak adsorption of reactants and products. The apparent activation energy was found to be 13 kcal/mol and intrinsic kinetic constant 33 cm6 mol-1 gcat-1 s-1. This study was further extended to synthesis of methyl isobutyl ketone (MIBK) from acetone in solvent free condition. Similar experimental and theoretical analysis was done for MIBK synthesis for which the activation energy and intrinsic kinetic constant were found to be 12 kcal/mol and 4 cm6 mol-1 gcat-1 s-1, respectively.

Embodiments of the present invention describe systems and methods for production of methyl isobutyl ketone (MIBK) from acetone and hydrogen in a two-step process. The composition of the product stream from the first reaction step is adjusted so that the resulting stream can undergo a favorable liquid-liquid separation in a decanter, and an MO rich product stream can be recovered. The composition of the feed to the decanter is controlled by choosing the number of reactor stages for the first reaction step and their operating temperatures, and/or by recycling some MIBK to the decanter feed. The method does not require a substantially complete conversion of acetone in the first reaction step, nor does it require a removal of DAA from the product of the first reaction step by separation.

A novel and practical oxidation of alcohols to carbonyl compounds using NaOCl in the presence of catalytic amounts of imide compound and nitroxyl radical has been developed. A wide variety of aliphatic, benzylic primary alcohols, and secondary alcohols were oxidized to afford the corresponding aldehydes and ketones in up to 98% yield without undesired halogenation on aromatic rings or double bonds. The oxidation safely proceeded not only in the presence of K2CO3 but also by a slow addition of NaOCl without tedious pH adjustment.

We report an alternative pathway to the Wacker oxidation of internal olefins involving epoxidation of trans-alkenes followed by a mild and highly regioselective isomerization to give the major ketone isomers in 66-98% yield. Preliminary kinetics and isotope labeling studies suggest epoxide ring opening as the turnover limiting step in our proposed mechanism. A similar catalytic system was applied to the kinetic resolution of select trans-epoxides to give synthetically useful selectivity factors of 17-23 for benzyl-substituted substrates.

Production of structurally diverse chiral amines via biocatalytic transamination is challenged by severe steric interference in a small active site pocket of ω-transaminase (ω-TA). Herein, we demonstrated that structure-guided remodeling of a large pocket by a single point mutation, instead of excavating the small pocket, afforded desirable alleviation of the steric constraint without deteriorating parental activities toward native substrates. Molecular modeling suggested that the L57 residue of the ω-TA from Ochrobactrum anthropi acted as a latch that forced bulky substrates to undergo steric interference with the small pocket. Removal of the latch by a L57A substitution allowed relocation of the small pocket and dramatically improved activities toward various arylalkylamines and alkylamines (e.g., 1100-fold increase in kcat/KM for α-propylbenzylamine). This approach may provide a facile strategy to broaden the substrate specificity of ω-TAs.

Supported platinum catalysts are studied for the reductive amination of ketones under ammonia and hydrogen. For a model reaction with 2-adamantanone, Pt-loaded MoOx/TiO2 (Pt-MoOx/TiO2) shows the highest yield of primary amine. The catalyst is effective for the selective transformation of various aliphatic and aromatic ketones to the corresponding primary amines, which demonstrates the first example of the selective synthesis of primary amines by this reaction. The yield of the amine increases with increase in the negative shift of the C￡O stretching band in the infrared spectra of adsorbed acetone on the catalysts, suggesting that Lewis acid sites on the support material play an important role in this catalytic system.

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.

The efficient deprotection of several acetals, dithioacetals, and tetrahydropyranyl (THP) ethers under ambient conditions, using chloral hydrate in hexane, is described. Excellent yields were realized for a wide range of both aliphatic and aromatic substrates. The method is characterized by mild conditions (room temperatures or below), simple workup, and the ready availability of chloral hydrate. High chemoselectivity was also observed in the deprotection, acetonides, esters, and amides being unaffected under the reaction conditions. Products were generally purified chromatographically and identified spectrally. These results constitute a novel addition to current methodology involving a widely employed deprotection tactic in organic synthesis. It seems likely that the mechanism of the reaction involves adsorption of the substrate on the surface of the sparingly soluble chloral hydrate.