- Electrocatalytic features of a heme protein attached to polymer-functionalized magnetic nanoparticles
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Direct electron-transfer and electrocatalytic kinetics of covalently attached myoglobin (MB) films on magnetic nanoparticles (MB-MNP covalent), in comparison to the corresponding physisorbed films and individual components, are reported for the first time. MB-MNP covalent ("-" denotes a covalent linkage) was adsorbed onto a cationic poly(ethyleneimine) layer (PEI) coated high-purity graphite (HPG) electrode. Similarly, films of myoglobin physisorbed on magnetic nanoparticles (MB/MNPadsorbed, "/" denotes a noncovalent nature), only MB, or only MNP were constructed on HPG/PEI electrodes for comparison. The observed electron-transfer rate constants (ks, s-1) were in the following order: MB-MNPcovalent (69 ± 6 s -1), MB/MNPadsorbed (37 ± 2 s-1), only MB (27 ± 2 s-1), and only MNP (16 ± 3 s-1). The electrocatalytic properties of these films were investigated with the aid of tert-butylhydroperoxide as a model reactant, and its reduction kinetics were examined. We observed the following order of catalytic current density: MB-MNPcovalent > MB/MNPadsorbed > only MNP > only MB, in agreement with the electron-transfer (ET) rates of MB-MNP covalent and MB/MNPadsorbed films. The crucial function of MNP in favorably altering the direct ET and electrocatalytic properties of both covalently bound MB and physisorbed MB molecules are discussed. In addition, the occurrence of a highly enhanced electron-hopping mechanism in the designed covalent MB-MNPcovalent films over the corresponding physisorbed MB/MNPadsorbed film is proposed. The enhanced electron-transfer rates and catalytic current density suggest the advantages of using metalloenzymes covalently attached to polymer-functionalized magnetic nanoparticles for the development of modern highly efficient miniature biosensors and bioreactors.
- Krishnan, Sadagopan,Walgama, Charuksha
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- Correlation of the product E/Z framework geometry and O/O vs O/N regioselectivity in the dialkylation of hyponitrite
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The products from the alkylation of silver hyponitrite with tert-butyl bromide, tert-amyl bromide, p-tert-butyl benzylbromide, and chlorotriethylsilane have been determined. In the reaction of tert-butyl bromide the formation of three new products, namely
- Arulsamy, Navamoney,Bohle, D. Scott,Imonigie, Jerome A.,Sagan, Elizabeth S.
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- Kinetics of Oxidation of Hydrazine and of t-Butylhydrazine using Tris(dimethylglyoximato)nickelate(IV) in the Presence of Added Cu(2+) (aq)
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The kinetics of the oxidation of hydrazine and t-butylhydrazine using tris(dimethylglyoximato)nickelate(IV), (2-), in the presence of added Cu(2+)(aq), and in the pH range 5.0 - 7.0 at 35 deg C and I = 0.25 mol dm-3 in aqueous medium, follow pseudo-first-order and pseudo-zero-order disappearance of the NiIV complex, respectively.Results of the Cu(2+) (aq)-promoted oxidation of hydrazine by (2-) are consistent with a probable scheme involving pH-dependent equilibrium formation of intermediate adducts between the NiIV and CuII-hydrazine complex species present in the solution and subsequent rate-determining electron transfer(s) to the adduct(s) from the hydrazine species in the presence of H(1+).Results of the Cu(2+) (aq)-catalyzed oxidation of t-butylhydrazine are interpreted in terms of a probable mechanism involving a rate-determining decomposition of the 1:1 intermediate complex between the CuII and t-butylhydrazine species in the solution, with a concomitant electron transfer.While the oxidation of hydrazine leads to nitrogen, the main products of the t-butylhydrazine oxidation are nitrogen and t-butyl alcohol.
- Acharya, Sridhara,Neogi, Gautam,Panda, Rama Krushna,Ramaswamy, Dorai
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- Temperature dependence of the rate and activation parameters for tert-butyl chloride solvolysis: Monte Carlo simulation of confidence intervals
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The solvolysis rate constants (kobs) of tert-butyl chloride are measured in 20%(v/v) 2-PrOH-H2O mixture at 15 temperatures ranging from 0 to 39°C. Examination of the temperature dependence of the rate constants by the weighted least squares fitting to two to four terms equations has led to the three-term form, lnkobs=a1+a 2T-1+a3lnT, as the best expression. The activation parameters, ΔH? and ΔS ?, calculated by using three constants a1, a 2 and a3 revealed the steady decrease of ≈1 kJmol -1 per degree and 3.5 JK-1mol-1 per degree, respectively, as the temperature rises. The sign change of ΔS ? at ≈20.0°C and the large negative heat capacity of activation, ΔCp?=-1020 JK -1mol-1, derived are interpreted to indicate an S N1 mechanism and a net change from water structure breaking to electrostrictive solvation due to the partially ionic transition state. Confidence intervals estimated by the Monte Carlo method are far more precise than those by the conventional method.
- Sung, Dae Dong,Kim, Jong-Youl,Lee, Ikchoon,Chung, Sung Sik,Park, Kwon Ha
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- Decomposition of tert-butyl hydroperoxide into tert-butyl alcohol and O2 catalyzed by birnessite-type manganese oxides: Kinetics and activity
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Birnessite-type manganese oxides (M-OL-1s, M = K, Mg, Fe, Ni and Cu) are first reported to efficiently catalyze the decomposition of tert-butyl hydroperoxide (TBHP) into tert-butyl alcohol (TBA) and O2 with a 100% selectivity towards TBA under heterogeneous conditions. The same form of overall second-order kinetic equations is fitted out for the M-OL-1s and explained by the proposed mechanism. Life tests and XRD analyses demonstrate no losses in both the activity and the birnessite-type structure after the reaction.
- Qi, Lin,Qi, Xingyi,Wang, Lili,Feng, Lili,Lu, Shupei
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- Possible Role of Non-hydrogen-bonded Units in the Chemistry of Liquid Water
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Pure liquid water is thought to contain ca. 8 molpercent of non-hydrogen-bonded (free) OH groups and lone-pair (LP) groups.It is suggested that, as well as playing important roles in the physical and spectroscopic properties of liquid water, these groups are important in controlling solvation and in certain chemical reactions.The postulate is that if a reaction that makes a significant contribution to the overall rate involves (OH)free groups, then solutes that increase or decrease the free> will increase or decrease the rate.Conversely, if (LP)free groups are reactants, than changes in free> will similarly affect the reaction rate.The hydrolysis of tert-butyl iodide in binary solvent systems has been measured spectrophotometrically at 7 deg C, and it is shown that the results can be reasonably understood in terms of the above theory.It is clearly established that basic aprotic cosolvents lead to rapid decreases in the rates of SN1 reactions and our results are in good agreement.For simple 1:1 electrolytes the salt effect results in rate enhancement, as expected for an 'ionisation' process.However, tetra n-butylammonium bromide causes a dramatic fall in the rate of hydrolysis.This is expected, if the key reaction involves (OH)free groups, as is indicated by the rate decreases caused by basic solutes.Thus, for simple salts, cations and anions have similar solvation numbers and so induce only small changes in the concentration of 'free' water groups.However R4N+ ions do not form bonds to water so the anions, which solvate by hydrogen bonding to OH units, cause a large fall in free>, and hence there is a large negative contribution to the rate of hydrolysis.Taking the primary solvation number of Br- as 6, the results agree well with those for solvents such as dimethylformamide, which has a solvation number ca. 2.Finally, it is pointed out that reactions involving attack by oxygen via an electron pair, such as the extraction of H+ from an organic reactant should behave in just the opposite manner.This is indeed the case.
- Pay, Nicholas G. M.,Symons, Martyn C. R.
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- A search for mode-selective chemistry: The unimolecular dissociation of t-butyl hydroperoxide induced by vibrational overtone excitation
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The use of optoacoustic spectroscopy permits both the monitoring of the overtone excitation of t-butylhydroperoxide (t-BuOOH) and the in situ detection of the resulting reaction product t-butanol (t-BuOH).The sample is contained in a reaction cell, equippedwith a microphone, in which all surfaces have been specially passivated.The cell is placed inside the cavity of a dye laser tuned to excite the 5-0 O-H stretch of the t-BuOOH at 619.0 nm.The dissociation process yields directly OH and t-BuO, and the latter readily abstracts a hydrogen atom from a parent molecule to form t-butanol (t-BuOH).The appearance rate of t-BuOH is obtained by ratioing the area under the 5-0 O-H stretch of tBuOH to that of a combination band of t-BuOOH.At low pressures, below 40 Torr, a plot of the reciprocal of the t-BuOH appearance rate versus total pressure shows near linear behavior.This linearlity can be well described by a statistical model (RRKM) when careful averaging of the dissociation rate over the thermal energy distribution of the photoactivated molecules is included.At pressures above 40 Torr, a marked deviation from linearity appears.This deviation is fit to a kinetic model in which the dissociation rate of an energy nonrandomized molecule competes with the rate of intramolecular energy relaxation.This places a lower bound of >= 5.0*1011 s-1 on the rate of energy randomization.A discussion of this model in the context of other possible kinetic schemes as well as other photoactivated and chemically activated systems is presented.
- Chandler, David W.,Farneth, William E.,Zare, Richard N.
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- Homolytic cleavage of the O-Cu(II) bond: XAFS and EPR spectroscopy evidence for one electron reduction of Cu(II) to Cu(i)
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The investigation into the active copper(i) catalysts from copper(ii) precursors has become a fundamental and important task in copper catalysis. In this work, we demonstrate that the tBuO- anion serves not only as a base but also as a mediator to promote the reduction of Cu(ii) to Cu(i) in copper catalysis. XAFS and EPR spectroscopy evidence the [Cu(OtBu)3]- ate complex as the key intermediate which undergoes homolytic-cleavage of the O-Cu(ii) bond generating [Cu(OtBu)2]- ate complex.
- Yi, Hong,Zhang, Guanghui,Xin, Jie,Deng, Yi,Miller, Jeffrey T.,Kropf, Arthur J.,Bunel, Emilio E.,Qi, Xiaotian,Lan, Yu,Lee, Jyh-Fu,Lei, Aiwen
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- Enhanced catalytic performance of porphyrin cobalt(II) in the solvent-free oxidation of cycloalkanes (C5~C8) with molecular oxygen promoted by porphyrin zinc(II)
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Dual-metalloporphyrins catalytic system based on T(p-Cl)PPCo and T(p-Cl)PPZn was presented to enhance the oxidation of cycloalkanes, especially for cyclohexane, the selectivity towards KA oil increasing from 90.7% to nearly 100.0%, meanwhile the conversion increasing from 3.42% to 4.29%. Enhancement on conversion and selectivity was realized simultaneously. In the dual-metalloporphyrins system, T(p-Cl)PPCo served the role to activate molecular oxygen and promote the decomposition of cyclohexyl hydroperoxide, and T(p-Cl)PPZn catalyzed the decomposition of cyclohexyl hydroperoxide to avoid unselective thermal decomposition. This protocol is also very applicable to other cycloalkanes and will provide a applicable strategy to enhance the oxidation of alkanes.
- Shen, Hai-Min,Zhang, Long,Deng, Jin-Hui,Sun, Jing,She, Yuan-Bin
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- CHANGE IN THE REACTIVITY OF DI-tert-BUTYL PEROXIDE DURING HOMOLYSIS WITH AN INCREASE IN THE DEGREE OF CONVERSION AND PRESSURE
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It was found that the differential reactivity (kd') of di-tert-butyl peroxide (DTBP) in a solution of 2-methoxy- (1) and 2-ethoxytetrahydropyran (2) at 130 deg C and pressures p = 20 and 1000 MPa is a periodic function of the degree of conversion, arbitrarily measured by the concentration of tert-butyl alcohol (TBA) formed.The function kd' = F() was calculated with the spline approximation (SA) of the experimental as a function of the reaction time τ, giving a continuous curve of d/dτ as a function of τ.The integral reactivity kd = G() calculated with the kinetic equation for a first-order reaction for decomposition of DTBP in 1, 2, 1+ C6H6 and 2 + C6H6 in three segments of τ in the range of p = 20-1000 MPa changes differently with an increase in the degree of conversion for different p.The volume activation effects (ΔVp) determined by SA of the experimental ln kd as a function of p were calculated for close degrees of conversion, = 0.1-0.14 M.The ΔVp as a function of p obtained were compared with the similarly processed published data on decomposition of DTBP in n-heptane and dicumyl peroxide (DCP) in different aromatic solvents.The results were attributed to the effect of the type of packing of the solvent molecules surrounding the reacting molecule on the reactivity of the peroxide and not to the effect of radical recombination in the primary cage. Keywords: di-tert-butyl peroxide, homolysis, high pressure, role of solvent.
- Zhulin, V. M.,Khueidzha, I.,Koreshkov, Yu. D.
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- Characterization of co-metabolic biodegradation of methyl: Tert -butyl ether by a Acinetobacter sp. strain
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Co-metabolic bioremediation is a promising approach for the elimination of methyl tert-butyl ether (MTBE), which is a common pollutant found worldwide in ground water. In this paper, a bacterial strain able to co-metabolically degrade MTBE was isolated and named as Acinetobacter sp. SL3 based on 16S rRNA gene sequencing analysis. Strain SL3 could grow on n-alkanes (C5-C8) accompanied with the co-metabolic degradation of MTBE. The number of carbons present in the n-alkane substrate significantly influenced the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA), with n-octane resulting in a higher MTBE degradation rate (Vmax = 36.7 nmol min-1 mgprotein-1, Ks = 6.4 mmol L-1) and lower TBA accumulation rate. A degradation experiment in a fed-batch reactor revealed that the efficiency of MTBE degradation by Acinetobacter sp. strain SL3 did not show an obvious decrease after nine rounds of MTBE replenishment ranging from 0.1-0.5 mmol L-1. The results of this paper reveal the preferable properties of Acinetobacter sp. SL3 for the bioremediation of MTBE via co-metabolism and leads towards the development of new MTBE elimination technologies.
- Li, Shanshan,Wang, Dan,Du, Dan,Qian, Keke,Yan, Wei
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- Partial Oxidation of Olefins: Conversion of Isobutene to tert-Butyl Alcohol on Oxygen-Covered Rh(111)
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The selective oxidation reactions of isobutene on oxygen-covered Rh(111) have been investigated by temperature-programmed reaction and X-ray photoelectron spectroscopies.Isobutene is selectively oxidized to tert-butyl alcohol by atomic oxygen on Rh(111) with coverages in the range of 0.3-0.5.Desorption of isobutene and combustion to carbon monoxide, carbon dioxide, and water are competing processes.One C-O, one C-H and one O-H bond are formed during the oxidation of isobutene to tert-butyl alcohol.No reversible C-H bond activation and, specifically, no allylic C-H bond breaking is induced in the isobutene that reacts to produce tert-butyl alcohol.We propose that oxygen directly adds to the 2-carbon of isobutene followed by C-H bond formation to afford tert-butoxide at ca. 250 K.The C-H bond breaking of tert-butoxide and the other hydrocarbon fragments is proposed to be the rate-limiting step for the evolution of tert-butyl alcohol, isobutene, and water at ca. 370 K.Nonselective dehydrogenation occurs at the clean Rh sites of the oxygen-covered surfaces at ca. 250 K and involves both methylenic and allylic C-H bond breaking to provide a source of hydrogen for tert-butoxide formation.The product yields and selectivity depend on the oxygen coverage, and a maximum tert-butyl alcohol yield is observed on Rh(111) with an oxygen coverage of ca. 0.4 monolayers.Intermediate oxygen coverages optimize the requirements for C-O addition, without dehydrogenation, and some dehydrogenation to produce a source of adsorbed hydrogen.Isobutene oxidation on Rh(111) is dramatically different from that on Ag or metal oxides, in particular, because the oxygen on Rh(111) does not serve as a Bronsted base.
- Xu, Xueping,Friend, C. M.
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- Kinetics of a Hydrolysis Reaction in an Oil/Water Microemulsion System Near the Critical Point
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We have constructed the pseudoternary phase diagram of surfynol465?+?n-butanol?+?cyclohexane?+?H2O with km?=?2 (where km is the weight ratio of surfynol465 to n-butanol) by the water titration method. Electrical conductivity measurements were employed to investigate the microstructures of the single-phase region. In the oil/water microemulsion region, we have measured the hydrolysis reaction rate of 2-bromo-2-methylpropane near and far away from the critical point. It was found that the Arrhenius equation was valid for correlating experimental measurements far away from the critical point but a significant acceleration effect exists near the critical point, which is not consistent with thermodynamic interpretation of Griffiths and Wheeler.
- Yang, Ya,Jin, Jing,Wang, Jinshou,Shi, Zhen,Zhang, Shenghui
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- Effect of Temperature on the Specific Heat of Activation for the Solvolysis of Tert-butyl Chloride and Tert-pentyl Chloride in Water
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Precise first-order rate constants for the solvolysis of tert-butyl and tert-pentyl chlorides have been determined in water at temperatures up to 50 deg C for butyl chloride and 41 deg C for pentyl chloride.The results have been compared with previously published data on the hydrolysis of the two chlorides at lower temperatures, and, on detailed analysis, the results have provided a reliable picture of the temperature variation of the specific heat of activation (ΔCp) for these hydrolyses.
- Adams, Paul A.,Sheppard, John G.
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- Effect of Fluorination of the meso-Phenyl Groups on Selective Tetraphenylporphyrinatometal(III)-catalysed Reactions of Isobutane with Molecular Oxygen
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A series of tetrakis(pentafluorophenyl)porphyrinatoiron(III) complexes are active catalysts for the selective low temperature hydroxylation of isobutane with molecular oxygen and provide thousands of of catalytic turnovers in the absence of any added co-reductants.
- Ellis, Jr., Paul E.,Lyons, James E.
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- Solvent Ionizing Power. Comparisons of Solvolyses of 1-Adamantyl Chlorides, Bromides, Iodides and Tosylates in Protic Solvents
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Solvolytic rate constants for 1-adamantyl iodide (1-AdI) in binary aqueous mixtures of ethanol, methanol, acetone, trifluoroethanol, and hexafluoroisopropyl alcohol and in acetic and formic acids are reported.Additional kinetic data for solvolyses of 1-adamantyl halides in 97percent w/w hexafluoroisopropyl alcohol/water were obtained by using a microconductivity cell (volume, ca. 0.4 mL).Kinetic data for iodine-catalyzed solvolyses of 1-AdI in methanol/water mixtures are also reported.A scale of solvent ionizing power for iodides (YI) is defined by log(k/k0)1-AdI=YI, where k is the rate constant for solvolysis of 1-AdI in any solvent at 25 deg C relative to 80percent v/v ethanol/water (k0).Correlations of YI and similarly defined scales for tosylates (YOTs) and bromides (YBr) with data for chlorides (YCl) show variations in slopes attributed to charge delocalization in the leaving group (slopes, Cl>Br>I>OTs); acidic solvents show significant deviations from the correlation lines.The effect of iodine catalysis increases as solvent ionizing power decreases, consistent with formation of the charge delocalized leaving group I3-.YI does not correlate satisfactorily with Kosower's Z values for aqueous and alcohol solvents, and the range of Z values is substantially greater in energy terms than the corresponding range of YI values.Our data provide qualified independent support for a recent proposal by Swain et al. that only two solvent properties correlate the major solvent effect on rates, equilibria and spectra.
- Bentley, William T.,Carter, Gillian E.,Roberts, Karl
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- Autocatalysis in oxidation reactions of verdazyl radicals with hydroperoxides
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The reaction of 2,4,6-triphenyl- and 2,3,4,6-tetraphenylverdazyl with tert-butyl hydroperoxide in acetonitrile solution and acetonitrile-water mixture was studied. This reaction was shown to be autocatalytic owing to verdazylium hydroxide formation in the course of the reaction. The main kinetic parameters were determined for the catalytic and non-catalytic reactions. Pleiades Publishing, Ltd., 2010.
- Buzulukov
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- New evaluation scheme for two-dimensional isotope analysis to decipher biodegradation processes: Application to groundwater contamination by MTBE
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Compound-specific analysis of stable carbon and hydrogen isotopes was used to assess the fate of the gasoline additive methyl tert-butyl ether (MTBE) and its major degradation product tert-butyl alcohol (TBA) in a groundwater plume at an industrial disposal site. We present a novel approach to evaluate two-dimensional compound-specific isotope data with the potential to identify reaction mechanisms and to quantify the extent of biodegradation at complex field sites. Due to the widespread contaminant plume, multiple MTBE sources, the presence of numerous other organic pollutants, and the complex biogeochemical and hydrological regime at the site, a traditional mass balance approach was not applicable. The isotopic composition of MTBE steadily changed from the source regions along the major contaminant plume (-26.4‰ to +40.0‰ (carbon); -73.1‰ to +60.3‰ (hydrogen)) indicating substantial biodegradation. Constant carbon isotopic signatures of TBA suggest the absence of TBA degradation at the site. Published carbon and hydrogen isotope fractionation data for biodegradation of MTBE under oxic and anoxic conditions, respectively, were examined and used to determine both the nature and the extent of in-situ biodegradation along the plume(s). The coupled evaluation of two-dimensional compound-specific isotope data explained both carbon and hydrogen fractionation data in a consistent way and indicate anaerobic biodegradation of MTBE along the entire plume. A novel scheme to reevaluate empiric isotopic enrichment factors (ε) in terms of theoretically based intrinsic carbon (12k/13k) and hydrogen ( 1k/2k) kinetic isotope effects (KIE) is presented. Carbon and hydrogen KIE values, calculated for different potential reaction mechanisms, imply that anaerobic biodegradation of MTBE follows a SN2-type reaction mechanism. Furthermore, our data suggest that additional removal process(es) such as evaporation contributed to the overall MTBE removal along the plume, a phenomenon that might be significant also for other field sites at tropic or subtropic climates with elevated groundwater temperatures (25°C).
- Zwank, Luc,Berg, Michael,Elsner, Martin,Schmidt, Torsten C.,Schwarzenbach, Rene P.,Haderlein, Stefan B.
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- Control of electrochemical and ferryloxy formation kinetics of cyt P450s in polyion films by heme iron spin state and secondary structure
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Voltammetry of cytochrome P450 (cyt P450) enzymes in ultrathin films with polyions was related for the first time to electronic and secondary structure. Heterogeneous electron transfer (hET) rate constants for reduction of the cyt P450s depended on heme iron spin state, with low spin cyt P450cam giving a value 40-fold larger than high spin human cyt P450 1A2, with mixed spin human P450 cyt 2E1 at an intermediate value. Asymmetric reduction-oxidation peak separations with increasing scan rates were explained by simulations featuring faster oxidation than reduction. Results are consistent with a square scheme in which oxidized and reduced forms of cyt P450s each participate in rapid conformational equilibria. Rate constants for oxidation of ferric cyt P450s in films by t-butyl hydroperoxide to active ferryloxy cyt P450s from rotating disk voltammetry suggested a weaker dependence on spin state, but in the reverse order of the observed hET reduction rates. Oxidation and reduction rates of cyt P450s in the films are also likely to depend on protein secondary structure around the heme iron.
- Krishnan, Sadagopan,Abeykoon, Amila,Schenkman, John B.,Rusling, James F.
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- Efficient oxidation of cycloalkanes with simultaneously increased conversion and selectivity using O2 catalyzed by metalloporphyrins and boosted by Zn(AcO)2: A practical strategy to inhibit the formation of aliphatic diacids
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The direct sources of aliphatic acids in cycloalkanes oxidation were investigated, and a strategy to suppress the formation of aliphatic acids was adopted through enhancing the catalytic transformation of oxidation intermediates cycloalkyl hydroperoxides to cycloalkanols by Zn(II) and delaying the emergence of cycloalkanones. Benefitted from the delayed formation of cycloalkanones and suppressed non-selective thermal decomposition of cycloalkyl hydroperoxides, the conversion of cycloalkanes and selectivity towards cycloalkanols and cycloalkanones were increased simultaneously with satisfying tolerance to both of metalloporphyrins and substrates. For cyclohexane, the selectivity towards KA-oil was increased from 80.1% to 96.9% meanwhile the conversion was increased from 3.83 % to 6.53 %, a very competitive conversion level with higher selectivity compared with current industrial process. This protocol is not only a valuable strategy to overcome the problems of low conversion and low selectivity lying in front of current cyclohexane oxidation in industry, but also an important reference to other alkanes oxidation.
- Shen, Hai-Min,Wang, Xiong,Ning, Lei,Guo, A-Bing,Deng, Jin-Hui,She, Yuan-Bin
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- Selective Functionalization of Hydrocarbons Using a ppm Bioinspired Molecular Tweezer via Proton-Coupled Electron Transfer
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An expanded porphyrin-biscopper hexaphyrin was introduced as a bioinspired molecular tweezer to co-catalyze functionalization of C(sp3)-H bonds. Theoretical and experimental investigations suggested that the biscopper hexaphyrin served as a molecular tweezer to mimic the enzymatic orientation/proximity effect, efficiently activating the N-hydroxyphthalimide (NHPI) via light-free proton-coupled electron transfer (PCET), at an exceptionally low catalyst loading of 10 mol ppm. The resulting N-oxyl radical (PINO) was versatile for chemoselective C-H oxidation and amination of hydrocarbons.
- Chen, Hongyu,Wang, Lingling,Xu, Sheng,Liu, Xiaohui,He, Qian,Song, Lijuan,Ji, Hongbing
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p. 6810 - 6815
(2021/06/28)
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- Low-Level Quantification oftert-Butyl Nitrite in a Pharmaceutical Intermediate
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A sensitive, reliable, and reproducible headspace gas chromatography-flame ionization detection method was developed and validated to detect and quantify low levels oftert-butyl nitrite (TBN). TBN is a reagent commonly used by synthetic chemists for nitrogen insertion reactions and is also a potential mutagenic impurity due to a structurally alerting nitrite group. However, there is an inherent analytical challenge in the quantification of TBN due to its chemical instability in solution (e.g., degradation of TBN totert-butyl alcohol, TBA, in protic solvents). The proposed methodology is based on stabilizing TBN in solution by adding imidazole to a sample diluent before static headspace gas chromatographic analysis. The gas chromatography method utilizes a high-polarity poly(ethylene glycol) stationary phase that provides the resolution of TBN from an interference peak in the sample matrix and facilitates the attainment of the required sensitivity of the TBN peak. The limit of detection (LOD) and limit of quantitation (LOQ) of this method were established as 0.05 μg mL-1(0.05 ppm) and 0.15 μg mL-1(0.15 ppm), respectively. Method validation experiments indicated excellent analytical performance of the method with respect to specificity (resolution of ～2.2 from a matrix interference peak), linearity (range: 16.7-1000% of the working concentration), precision (relative standard deviation, RSD, of 1.0% forn= 6 at LOQ level), and recovery (94% at LOQ level). This is the first report of a practical strategy to stabilize TBN for its trace-level quantification.
- Patel, Neha,Chokkalingam, Thambiraja,Das, Soumyajit,Saha, Subhrakanti,Jayaraman, Karthik,Bhutani, Hemant
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supporting information
p. 2415 - 2424
(2021/11/01)
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- PROCESS AND SYSTEM TO MAKE SUBSTITUTED LACTONES
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A process for oxidizing iso-butane with oxygen to produce t-butyl hydroperoxide and t-butyl alcohol; dehydrating at least a portion of the t-butyl alcohol to produce di-tert-butyl ether and isobutylene; epoxidizing at least a portion of the isobutylene with the t-butyl hydroperoxide to produce isobutylene oxide and t-butyl alcohol; and carbonylating at least a portion of the isobutylene oxide with carbon monoxide to produce pivalolactone.
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Paragraph 0052; 0055
(2021/02/05)
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- Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
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Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
- Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
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p. 2084 - 2092
(2021/04/02)
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- Method for recycling byproducts in synthesis of diphenyl sulfide compound
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The invention provides a method for recycling byproducts in synthesis of a diphenyl sulfide compound. The byproducts comprise alkyl alcohol and dimethyl disulfide. The method comprises the steps of (1) mixing the byproducts in synthesis of the diphenyl sulfide compound with a sodium nitrite aqueous solution, adding concentrated hydrochloric acid for reaction, and obtaining alkyl nitrite and dimethyl disulfide; and (2) mixing the products obtained in the step (1) with copper powder, adding an aniline compound for reaction, carrying out desolvation treatment on the obtained reaction solution toobtain a diphenyl sulfide compound and byproducts, and returning the byproducts to the step (1). According to the recycling method, the byproducts do not need to be separated, the byproducts serve asraw materials to be directly applied to synthesis of the diphenyl sulfide compound, the process steps are simple and safe, cyclic utilization of the materials is achieved, and the raw material cost ofindustrial production of the diphenyl sulfide compound and the treatment cost of industrial three wastes are remarkably reduced.
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Paragraph 0083; 0089-0091
(2021/03/30)
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- Chromium-Catalyzed Production of Diols From Olefins
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Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111
(2021/03/19)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
-
The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
-
p. 10590 - 10597
(2021/08/20)
-
- Ultrastable Cu Catalyst for CO2 Electroreduction to Multicarbon Liquid Fuels by Tuning C–C Coupling with CuTi Subsurface
-
Production of multicarbon (C2+) liquid fuels is a challenging task for electrocatalytic CO2 reduction, mainly limited by the stabilization of reaction intermediates and their subsequent C?C couplings. In this work, we report a unique catalyst, the coordinatively unsaturated Cu sites on amorphous CuTi alloy (a-CuTi@Cu) toward electrocatalytic CO2 reduction to multicarbon (C2-4) liquid fuels. Remarkably, the electrocatalyst yields ethanol, acetone, and n-butanol as major products with a total C2-4 faradaic efficiency of about 49 % at ?0.8 V vs. reversible hydrogen electrode (RHE), which can be maintained for at least 3 months. Theoretical simulations and in situ characterization reveals that subsurface Ti atoms can increase the electron density of surface Cu sites and enhance the adsorption of *CO intermediate, which in turn reduces the energy barriers required for *CO dimerization and trimerization.
- Duan, Chongxiong,Duan, Delong,Hu, Fei,Jiang, Jun,Jiang, Yawen,Kong, Tingting,Liu, Qi,Long, Ran,Lv, Xuefeng,Wang, Xiaonong,Xiong, Yujie,Yang, Li,Zeng, Longjiao
-
supporting information
p. 26122 - 26127
(2021/11/12)
-
- PROCESSES FOR FORMING GLYCOLS
-
This disclosure provides processes for forming glycols by upgrading hydrocarbons. In one embodiment, a process for forming a glycol includes introducing a first ether to a dihydrocarbyl peroxide to form a diether and a first alcohol. The process includes introducing the diether to water to form a glycol and a second alcohol. Processes of this disclosure may include one or more of: introducing a hydrocarbyl hydroperoxide to a third alcohol to form the dihydrocarbyl peroxide; oxidizing a first feed stream comprising a branched hydrocarbon to form the hydrocarbyl hydroperoxide and the first alcohol; and/or introducing the second alcohol to a catalyst to form a second ether.
- -
-
Paragraph 0095; 0096
(2020/05/28)
-
- One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
-
The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
- Coeck, Robin,De Vos, Dirk E.
-
supporting information
p. 5105 - 5114
(2020/08/25)
-
- Dehydration method of alcohol solvent
-
The invention discloses a dehydration method of an alcohol solvent, and belongs to the technical field of organic synthesis. According to the method, dialkyl dicarbonate is adopted as a water removalagent, 4-(N, N-dimethylamino) pyridine is adopted as a catalyst, the water removal reaction process is mild, and high-risk byproducts such as hydrogen cannot be generated. When an existing dehydrationmethod is used for treating an alcohol solvent with high water content, the reaction is violent, the control is not easy, and the treatment effect is not ideal enough. According to the method, a large amount of water reacts with dialkyl dicarbonate to generate corresponding alcohol and release inert carbon dioxide gas, the reaction is mild, the water content of the anhydrous alcohol solvent obtained through atmospheric distillation after the reaction can be reduced to 10ppm or below, and the requirements of most organic synthesis processes can be met.
- -
-
Paragraph 0018-0019; 0023
(2020/07/21)
-
- Reactivity and Product Analysis of a Pair of Cumyloxyl and tert-Butoxyl Radicals Generated in Photolysis of tert-Butyl Cumyl Peroxide
-
Alkoxyl radicals play important roles in various fields of chemistry. Understanding their reactivity is essential to applying their chemistry for industrial and biological purposes. Hydrogen-atom transfer and C-C β-scission reactions have been reported from alkoxyl radicals. The ratios of these two processes were investigated using cumyloxyl (CumO?) and tert-butoxyl radicals (t-BuO?), respectively. However, the products generated from the pair of radicals have not been investigated in detail. In this study, CumO? and t-BuO? were simultaneously generated from the photolysis of tert-butyl cumyl peroxide to understand the chemical behavior of the pair of radicals by analyzing the products and their distribution. Electron paramagnetic resonance and/or transient absorption spectroscopy analyses of radicals, including CumO? and t-BuO?, provide more information about the radicals generated during the photolysis of tert-butyl cumyl peroxide. Furthermore, the photoproducts of (3-(tert-butylperoxy)pentane-3-yl)benzene demonstrated that the ether products were formed in in-cage reactions. The triplet-sensitized reaction induced by acetophenone, which is produced from CumO?, clarified that the spin state did not affect the product distribution.
- Oyama, Ryoko,Abe, Manabu
-
p. 8627 - 8638
(2020/07/21)
-
- Catalytic epoxidation of propylene over a Schiff-base molybdenum complex supported on a silanized mesostructured cellular foam
-
A Schiff-base molybdenum complex (MoO2–salen) supported on mesostructured cellular foam (MCF) was initially prepared by an in situ synthesis method under acidic conditions. Following silanization modification, a MoO2–salen?MCF-S sample with improved surface hydrophobicity was obtained. The ligand environment of molybdenum within the samples has been analyzed by Fourier-transform infrared spectroscopy, ultraviolet/visible spectroscopy, and X-ray photoelectron spectroscopy. Furthermore, the textural and structural properties of the corresponding materials have been characterized by nitrogen adsorption–desorption isotherms and transmission electron microscopy. Despite of the presence of fewer MoO2 species, the results showed that MoO2–salen?MCF-S has more active Mo centers than MoO2–salen and MoO2–salen?MCF on the basis of maintaining the mesoporous structure. The catalytic performances of the synthesized samples were assessed in the epoxidation of propylene with tert-butyl hydroperoxide (TBHP) as an oxidant, and the mechanism of propylene epoxidation under MoO2–salen?MCF was given. The prepared MoO2–salen?MCF-S material showed the best epoxidation performance with 1,2-dichloroethane as a solvent and a molar ratio of propylene to TBHP of 10:1 at 120 °C, giving a TBHP conversion of up to 100% after 1 h, with selectivities for propylene oxide and tert-butyl alcohol reaching 94.7% and 84.6%, respectively.
- Chen, Dawei,Jiang, Haoran,Yuan, Xia,Zhang, Xiaoyu
-
-
- Phenylene-bridged bis(benzimidazolium) (BBIm2+): a dicationic organic photoredox catalyst
-
A dicationic photoredox catalyst composed of phenylene-bridged bis(benzimidazolium) (BBIm2+) was designed, synthesised and demonstrated to promote the photochemical decarboxylative hydroxylation and dimerisation of carboxylic acids. The catalytic activity of BBIm2+ was higher than that for a monocation analogue, suggesting that the dicationic nature of BBIm2+ plays a key role in these decarboxylative reactions. The rate constant for the decay of the triplet-triplet absorption of the excited BBIm2+ increased with increasing concentration of the carboxylate anion with a saturated dependence, suggesting that photoinduced electron transfer occurs within the ion pair complex composed of the triplet excited state of BBIm2+ and a carboxylate anion.
- Kodama, Takuya,Kubo, Maiko,Shinji, Wataru,Ohkubo, Kei,Tobisu, Mamoru
-
p. 12109 - 12117
(2020/11/27)
-
- Functional models of nonheme diiron enzymes: Reactivity of the μ-oxo-μ-1,2-peroxo-diiron(iii) intermediate in electrophilic and nucleophilic reactions
-
The reactivity of the previously reported peroxo-adduct [FeIII2(μ-O)(μ-1,2-O2)(IndH)2(solv)2]2+ (1) (IndH = 1,3-bis(2-pyridyl-imino)isoindoline) has been investigated in nucleophilic (e.g., deformylation of alkyl and aryl alkyl aldehydes) and electrophilic (e.g. oxidation of phenols) stoichiometric reactions as biomimics of ribonucleotide reductase (RNR-R2) and aldehyde deformylating oxygenase (ADO) enzymes. Based on detailed kinetic and mechanistic studies, we have found further evidence for the ambiphilic behaviour of the peroxo intermediates proposed for diferric oxidoreductase enzymes.
- Kripli, Balázs,Szávuly, Miklós,Csendes, Flóra Viktória,Kaizer, József
-
supporting information
p. 1742 - 1746
(2020/02/20)
-
- DMSO-Triggered Complete Oxygen Transfer Leading to Accelerated Aqueous Hydrolysis of Organohalides under Mild Conditions
-
Addition of DMSO is found to greatly accelerate the aqueous hydrolysis of organohalides to alcohols, providing a neutral, more efficient, milder and more economic process. Mechanistic studies using 18O-DMSO and 18O-H2O showed that, contrary to the opinion that DMSO works as a dipolar solvent to enhance water's nucleophilicity, the accelerating effect comes from a complete oxygen transfer from DMSO to organohalides through generation of ROS+Me2?X? salts through C?O bond formation, followed by O?S bond disassociative hydrolysis of ROS+Me2?X? with water. This method is applicable to a wide range of organohalides and thus may have potential for practical industrial application, owing to easy recovery of DMSO from the H2O/DMSO mixture by regular vacuum rectification.
- Liu, Haicheng,Liu, Jianping,Cheng, Xiaokai,Jia, Xiaojuan,Yu, Lei,Xu, Qing
-
p. 2994 - 2998
(2019/01/04)
-
- Preparation method of tert-butyl alcohol
-
The invention discloses a preparation method of tert-butyl alcohol, which comprises the following steps: by using isobutane and oxygen as reaction raw materials, adding a certain amount of free radical initiator and solvent, controlling the reaction temperature at 50-90 DEG C and the reaction pressure at 0.5-1.5 MPa, and carrying out selective oxidation under the catalysis of six-membered bimetalporphyrin to prepare tert-butyl alcohol. The active center of the catalyst is selected from one of iron, cobalt, nickel, copper or zinc. The method has the advantages of mild reaction conditions, richraw material sources, simple process and high conversion rate and selectivity.
- -
-
Paragraph 0021-0044
(2019/12/02)
-
- Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol
-
The nature of active acid sites of zeolite H-BEA with different Si/Al ratios (15-407) in liquid phase etherification of isobutylene with ethanol in a continuous flow reactor in the temperature range 80-180 °C has been explored. We describe and discuss data concerning the strength and concentration of acid sites of H-BEA obtained by techniques of stepwise (quasi-equilibrium) thermal desorption of ammonia, X-ray diffraction, low-Temperature adsorption of nitrogen, FTIR spectroscopy of adsorbed pyridine and solid-state 27Al MAS NMR. The average values of the adsorption energy of NH3 on H-BEA were experimentally determined as 63.7; 91.3 and 121.9 mmol g-1 (weak, medium, and strong, respectively). In agreement with this, a correlation between the rate of ethyl-Tert-butyl ether synthesis and the concentration of weak acid sites (ENH3 = 61.6-68.9 kJ mol-1) has been observed. It was concluded that the active sites of H-BEA for this reaction are Br?nsted hydroxyls representing internal silanol groups associated with octahedrally coordinated aluminum in the second coordination sphere.
- Vlasenko, Nina V.,Kochkin, Yuri N.,Telbiz, German M.,Shvets, Oleksiy V.,Strizhak, Peter E.
-
p. 35957 - 35968
(2019/11/20)
-
- Synthesis of β-ketoiminate and β-iminoesterate tungsten (VI) oxo-alkoxide complexes as AACVD precursors for growth of WOx thin films
-
The tungsten (VI) oxo-alkoxide complexes WO(OR)3L [R = tBu; L = acNac, etNac, tbNac, acNacMe, acNacEt] (1–5) and WO(OCH3)3(acNac) (6) have been synthesized. The isomeric purity of these complexes depends on the steric bulk of the substituent on the imino nitrogen of the chelating ligand. The thermal properties of the complexes have been evaluated to assess the effect of the β-ketoiminate or β-iminoesterate ligands. WO(OC(CH3)3)3(acNac) (1) has been used as a precursor for aerosol assisted chemical vapor deposition (AACVD) of WOx thin films at temperatures from 250 to 450 °C. The results of mass spectrometry and thermolysis studies have been used to propose possible precursor decomposition pathways during film deposition.
- Su, Xiaoming,Kim, Taehoon,Abboud, Khalil A.,McElwee-White, Lisa
-
p. 548 - 557
(2018/11/10)
-
- Interconverting Lanthanum Hydride and Borohydride Catalysts for C=O Reduction and C?O Bond Cleavage
-
The high catalytic reactivity of homoleptic tris(alkyl) lanthanum La{C(SiHMe2)3}3 is highlighted by C?O bond cleavage in the hydroboration of esters and epoxides at room temperature. The catalytic hydroboration tolerates functionality typically susceptible to insertion, reduction, or cleavage reactions. Turnover numbers (TON) up to 10 000 are observed for aliphatic esters. Lanthanum hydrides, generated by reactions with pinacolborane, are competent for reduction of ketones but are inert toward esters. Instead, catalytic reduction of esters requires activation of the lanthanum hydride by pinacolborane.
- Patnaik, Smita,Sadow, Aaron D.
-
supporting information
p. 2505 - 2509
(2019/02/01)
-
- PROCESS FOR MAKING FORMIC ACID UTILIZING LOWER-BOILING FORMATE ESTERS
-
Disclosed is a process for recovering formic acid from a formate ester of a C3 to C4 alcohol. Disclosed is also a process for producing formic acid by carbonylating a C3 to C4 alcohol, hydrolyzing the formate ester of the alcohol, and recovering a formic acid product. The alcohol may be dried and returned to the reactor. The process enables a more energy efficient production of formic acid than the carbonylation of methanol to produce methyl formate.
- -
-
Paragraph 00177; 00178
(2019/02/15)
-
- Additive-free cobalt-catalysed hydrogenation of carbonates to methanol and alcohols
-
Reduction of various organic carbonates to methanol and alcohols can be achieved in the presence of a molecularly-defined homogeneous cobalt catalyst. Specifically, the use of Co(BF4)2 in combination with either commercial or tailor-made tridentate phosphine ligands allows for additive-free hydrogenations of carbonates. Optimal results are obtained at relatively mild conditions (120 °C, 50 bar hydrogen pressure) in the presence of xylyl-Triphos L4.
- Ferretti, Francesco,Scharnagl, Florian Korbinian,Dall'Anese, Anna,Jackstell, Ralf,Dastgir, Sarim,Beller, Matthias
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p. 3548 - 3553
(2019/07/10)
-
- METHODS AND SYSTEMS FOR CONVERTING HYDROCARBONS
-
Methods and systems for converting hydrocarbons including exposing a portion of a hydroperoxide-containing feed including tert-butyl hydroperoxide to a solid deperoxidation catalyst under decomposition conditions to form an oxidation effluent comprising tert-butyl alcohol, wherein the solid deperoxidation catalyst comprises a manganese oxide octahedral molecular sieve, are provided herein. Further methods and systems for converting the oxidation effluent to an alkylation product are also provided herein.
- -
-
Paragraph 0036-0037; 0099-0100
(2018/06/29)
-
- Effect of Γ-alumina nanorods on CO hydrogenation to higher alcohols over lithium-promoted CuZn-based catalysts
-
To achieve high catalytic activities and long-term stability to produce higher alcohols via CO hydrogenation, the catalytic activities were tuned by controlling the loading amounts of γ-alumina nanorods and Al3+ ions added to modify Cu-Zn catalysts promoted with Li. The selectivity of higher alcohols and the CO conversion to higher alcohols over a Li-modified Cu0.45Zn0.45Al0.1 catalyst supported on 10% nanorods were 1.8 and 2.7 times higher than those with a Cu-Zn catalyst without nanorods and Al3+ ions, respectively. The introduction of the thermally and chemically stable γ-Al2O3 nanorod support and of Al3+ to the modified catalysts improves the catalytic activities by decreasing the crystalline size of CuO and increasing the total basicity. Along with the nanorods, a refractory CuAl2O4 formed by the thermal reaction of CuO and Al3+ enhances the long-term stability by increasing the resistance to sintering of the catalyst.
- Choi, SuMin,Kang, YoungJong,Kim, SangWoo
-
p. 188 - 196
(2017/10/16)
-
- Catalytic Upgrading of Ethanol to n-Butanol via Manganese-Mediated Guerbet Reaction
-
Replacement of precious metal catalysts in the Guerbet upgrade of ethanol to n-butanol with first-row metal complex catalysts is highly appreciated due to their economic and environmental friendliness. The manganese pincer complexes of the type [(RPNP)MnBr(CO)2] (R = iPr, Cy, tBu, Ph or Ad) are found to be excellent catalysts for upgrading ethanol to n-butanol. Under suitable reaction conditions and with an appropriate base, about 34% yield of n-butanol can be obtained in high selectivity. A detailed account on the effect of the temperature, solvent, nature, and proportion of base used and the stereoelectronic effects of the ligand substituents on the catalytic activity of the catalysts as well as the plausible deactivation pathways is presented.
- Kulkarni, Naveen V.,Brennessel, William W.,Jones, William D.
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p. 997 - 1002
(2018/02/14)
-
- CATALYST FOR ONE CARBON-REDUCTION REACTION, AND METHOD FOR PRODUCING ONE CARBON-REDUCTION COMPOUND USING THE SAME
-
PROBLEM TO BE SOLVED: To provide a method for producing selectively a one carbon-reduction compound, using a compound having a primary hydroxy group, a carboxyl group, or an alkoxycarbonyl group, or a lactone compound, as a substrate. SOLUTION: A method of obtaining a one carbon-reduction compound includes the reaction of a compound as a substrate represented by formula (1-1) or (1-2) or (1-3) with hydrogen in the presence of a catalyst in which a metal selected from Ru, Rh, Pd, Ir, and Pt is supported on a support selected from CeO2, hydroxyapatite, ZrO2, TiO2, hydrotalcite, SiO2, MgO, and Al2O3 (R1-R3 independently represent H, a substituted/unsubstituted monovalent hydrocarbon group, or a monovalent group in which two or more hydrocarbon groups are bound together through a linking group; R1-R3 may form a ring with adjacent carbon; L is a substituted/unsubstituted divalent hydrocarbon group or the like; and n is an integer of 0 or greater). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
- -
-
Paragraph 0060; 0070; 0071
(2018/07/28)
-
- Ru-Photoredox-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids through N-(acyloxy)phthalimide
-
Decarboxylative aminoxylation of aliphatic carboxylic acid derivatives with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) in the presence of ruthenium photoredox catalysis is reported. The key transformation entails a highly efficient photoredox catalytic cycle using Hantzsch ester as a reductant. The ensuing alkoxyamine can be readily converted to the corresponding alcohol in one pot, representing an alternative approach to access aliphatic alcohols under photoredox conditions.
- Zheng, Chao,Wang, Yuting,Xu, Yangrui,Chen, Zhen,Chen, Guangying,Liang, Steven H.
-
supporting information
p. 4824 - 4827
(2018/08/24)
-
- Cobalt(II)-Mediated Desulfurization of Thiophenes, Sulfides, and Thiols
-
Desulfurization of organosulfur compounds is a highly important reaction because of its relevance to the hydrodesulfurization (HDS) process of fossil fuels. A reaction system involving Co(BF4)2·6H2O and the dinucleating ligands HBPMP or HPhBIMP has been developed that could desulfurize a large number of thiophenes, sulfides, and thiols to generate the complexes [Co2(BPMP)(μ2-SH)(MeCN)](BF4)2 (1a), [Co2(BPMP)(SH)2](BF4) (1b), and [Co2(PhBIMP)(μ2-SH)(X)](BF4)2 [X = DMF (2a), MeCN (2c)], while the substrates are mostly converted to the corresponding alcohols/phenols. This convenient desulfurization process has been demonstrated for 25 substrates in 6 different solvents at room temperature.
- Ganguly, Tuhin,Das, Ayan,Jana, Manish,Majumdar, Amit
-
supporting information
p. 11306 - 11309
(2018/09/12)
-
- Catalytic Alkyl Hydroperoxide and Acyl Hydroperoxide Disproportionation by a Nonheme Iron Complex
-
Alkyl hydroperoxides are commonly used as terminal oxidants because they are generally acknowledged to be stable toward disproportionation compared with H2O2. We show that alkylperoxide disproportionation is effectively catalyzed by the [Fe(tpena)]2+ (tpena = N,N,N′-tris(2-pyridylmethyl)ethylendiamine-N′-acetate). A peroxidase-type mechanism, in other words, involvement of iron(IV)oxo species, is consistent with the rates and product distribution. Accordingly, O2, tert-butanol, and cumyl alcohol are concurrently produced for substrates tert-butyl hydroperoxide and cumene hydroperoxide, respectively, in the presence of [Fe(tpena)]2+ with O2 yields of 88% and 44%, respectively. Rate constants for initial O2 production ([Fe] 0.005 mol %) were measured to 3.66(6) and 0.29(3) mM s-1, respectively. Participating in the mechanism are spectroscopically detectable (UV-vis, EPR, resonance Raman) transient alkyl- and acyl-peroxide adducts, [FeIIIOOR(tpenaH)]2+ [R = C(CH3)3, C(CH3)2Ph, C(O)PhCl; T1/2 = 30 s (5 °C), 20 s (5 °C), 1 s (-30 °C)] with their common decay product [FeIVO(tpenaH)]2+. Concurrently organic radicals proposed to be ROO? were detected by EPR spectroscopy. A lower yield of O2 at 23% with an initial rate of 0.10(3) mM s-1 for the disproportionation of m-chloroperoxybenzoic acid is readily explained by catalyst inhibition by coordination of the product m-chlorobenzoic acid. Oxidative decomposition of the alkyl groups by a unimolecular β-scission pathway, favored for cumene hydroperoxide, competes with ROOH disproportionation. Despite the fact that the catalytic disproportionation is effective, external C-H substrates - when they are present in excess of ROOH - can be targeted and catalytically and selectively oxidized by ROOH using [Fe(tpena)]2+ as the catalyst.
- Wegeberg, Christina,Browne, Wesley R.,McKenzie, Christine J.
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p. 9980 - 9991
(2018/10/15)
-
- Deprotonation of a formato ligand by a: Cis-coordinated carbyne ligand within a bis(phenolate) tungsten complex
-
Deprotonation of a formato ligand by a cis-coordinated propylidyne ligand in a tungsten(vi) complex [(OSSO)W(CEt)(OCHO)] (3) that contains a tetradentate bis(phenolato) ligand (OSSO = {1,4-dithiabutanediyl-2,2′-bis(4,6-di-tert-butyl-phenolato)}) gave the dioxo complex [(OSSO)WO2] (4) along with CO, ethylene and propylene as major products of decomposition.
- Schindler, Tobias,Paparo, Albert,Nishiyama, Haruka,Spaniol, Thomas P.,Tsurugi, Hayato,Mashima, Kazushi,Okuda, Jun
-
supporting information
p. 13328 - 13331
(2018/10/17)
-
- Redox-regulated methionine oxidation of Arabidopsis thaliana glutathione transferase Phi9 induces H-site flexibility
-
Glutathione transferase enzymes help plants to cope with biotic and abiotic stress. They mainly catalyze the conjugation of glutathione (GSH) onto xenobiotics, and some act as glutathione peroxidase. With X-ray crystallography, kinetics, and thermodynamics, we studied the impact of oxidation on Arabidopsis thaliana glutathione transferase Phi 9 (GSTF9). GSTF9 has no cysteine in its sequence, and it adopts a universal GST structural fold characterized by a typical conserved GSH-binding site (G-site) and a hydrophobic co-substrate-binding site (H-site). At elevated H2O2 concentrations, methionine sulfur oxidation decreases its transferase activity. This oxidation increases the flexibility of the H-site loop, which is reflected in lower activities for hydrophobic substrates. Determination of the transition state thermodynamic parameters shows that upon oxidation an increased enthalpic penalty is counterbalanced by a more favorable entropic contribution. All in all, to guarantee functionality under oxidative stress conditions, GSTF9 employs a thermodynamic and structural compensatory mechanism and becomes substrate of methionine sulfoxide reductases, making it a redox-regulated enzyme.
- Tossounian, Maria-Armineh,Wahni, Khadija,Van Molle, Inge,Vertommen, Didier,Astolfi Rosado, Leonardo,Messens, Joris
-
-
- BiCl3: A versatile catalyst for the tetrahydropyranylation and depyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric diols
-
Bismuth trichloride as mild reagent, has been found to be a worthful catalyst for tetrahydropyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric di-ols. At room temperature the reagent THP(3,4-dihydro-2H-pyran) was successfully employed as pyranylating agent in presence of BiCl3catalyst without the use of a solvent and the yields of the products were found to be 90-96%. Further, the depyranylation of alcohols was achieved in quantitative yield by simple addition of MeOH using the same catalyst. The developed method was showed good chemo-selectivity in symmetrical diols for mono THP protection.
- Vijaya Durga,Balamurali Krishna,Baby Ramana,Santha Kumari,Vijay,Hari Babu
-
p. 1030 - 1034
(2017/05/26)
-
- PROCESS FOR THE PREPARATION OF TRIAZINE CARBAMATES
-
This invention relates to a process for the preparation of triazine carbamates by reacting a mixture of an aminotriazine A having at least two amino groups per molecule, an organic carbonate C, and a base B selected from the group consisting of alkoxides, and arylalkoxides of metals M, which may be alkali or earth alkali metals, and a solvent S which is a monohydric alcohol solvent R2OH or a mixture of solvents that comprises a monohydric alcohol R2OH, and a monohydric alcohol R3OH, or a mixture of solvents that comprises a monohydric alcohol R2OH with a further solvent selected from the group consisting of ether, alcohol, and hydrocarbon solvents, and adding to the products of the said reaction, an acid or a solution of an acid in a solvent.
- -
-
-
- HYDRATION REACTION METHOD FOR UNSATURATED HYDROCARBONS
-
PROBLEM TO BE SOLVED: To provide a hydration reaction method for unsaturated hydrocarbons with a high conversion rate and yield. SOLUTION: The present invention provides a hydration reaction method for unsaturated hydrocarbons that comprises a heating step of heating a mixture comprising an unsaturated hydrocarbon, water, and a catalyst with microwaves to obtain an unsaturated hydrocarbon hydrate, wherein, preferably, the catalyst is an acidic solid material; more preferably, the acidic solid material is crystalline silica alumina; further preferably, the silica alumina is ZSM-5 zeolite; the catalyst may be a heteropoly acid aqueous solution; and the unsaturated hydrocarbon may comprise a cyclic unsaturated hydrocarbon. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
- -
-
Paragraph 0050
(2017/01/12)
-
- Method for catalyzing and oxidizing olefin with sandwiching-type polyoxometalates
-
The invention discloses a method for catalyzing and oxidizing olefin with sandwiching-type polyoxometalates.The method includes the steps that an olefin substrate, a catalyst, hydrogen peroxide and solvent are added into a reactor under the condition of magnetic stirring, and after a reaction is conducted for a certain period of time at a certain temperature, cooling, filtering and separating are conducted; a solid phase is separated from a liquid phase, solvent is removed out of the liquid phase, and the catalyst is recycled after being washed and dried.According to the method for catalyzing and oxidizing olefin with sandwiching-type polyoxometalates, raw materials for the synthesized catalyst are easy to obtain and low in price, and the cost is saved; the preparation method is simple and safe, and the catalyst is high in activity and capable of being utilized multiple times, maintains high activity and selectivity and is suitable for application and popularization.
- -
-
Paragraph 0030-0037
(2017/04/05)
-
- A bionic catalytic oxydehydrogenation tertiary butyl alcohol
-
The invention discloses a method for preparing tert butyl alcohol through biomimetic catalysis iso-butane oxidation. The method comprises the steps that iso-butane is taken as raw material; metalloporphyrin is taken as a catalyst; oxygen is taken as an oxygen source; a certain amount of solvent, cocatalyst and radical initiator are added; the reaction temperature is controlled to be 50 to 120 DEG C; catalytic reaction is performed in the condition that the reaction pressure is 0.5 to 2MPa, so as to obtain tert butyl alcohol. The method has the advantages of mild reaction conditions, good convenience in operation, high conversion rate and high selectivity.
- -
-
Paragraph 0033; 0034
(2017/05/12)
-
- Sulfonic acid-functionalized LUS-1: an efficient catalyst for tetrahydropyranylation/depyranylation of alcohols
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Efficient acidic functionalization of mesoporous silica LUS-1 (Laval University Silica) and its application as a recyclable heterogeneous catalyst for DHP (3,4-dihydro-2H-pyran) protection of alcohols and the subsequent removal of the corresponding protecting group have been reported. This green method offers a number of advantages such as short reaction time, good yields of protection and deprotection, simple work-up procedure, recyclable catalyst, and environmentally friendly conditions.
- Rahimifard, Mahshid,Mohammadi Ziarani, Ghodsi,Badiei, Alireza
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p. 6327 - 6336
(2016/07/06)
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- PROCESSES FOR CONVERSION OF BIOLOGICALLY DERIVED MEVALONIC ACID
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The invention relates to a process comprising reacting mevalonic acid, or a solution comprising mevalonic acid, to yield a first product or first product mixture, optionally in the presence of a solid catalyst and/or at elevated temperature and/or pressure. The invention further relates to a process comprising: (a) providing a microbial organism that expresses a biosynthetic mevalonic acid pathway; (b) growing the microbial organism in fermentation medium comprising suitable carbon substrates, whereby biobased mevalonic acid is produced; and (c) reacting said biobased mevalonic acid to yield a first product or first product mixture.
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Paragraph 0107-0111
(2016/06/13)
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- Mechanistic insights into light-driven graphene-induced peroxide decomposition: Radical generation and disproportionation
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Interaction between adsorbed t-butyl peroxybenzoate and photoexcited graphene rendered trapped phenyl and t-butoxy radicals. Post-irradiation thermal desorption showed benzene, t-butanol, and isobutylene oxide as the end products. The required hydrogen at
- Chu, Ya-Lan,Chen, Yen-An,Li, Wei-Chin,Chu, Jean-Ho,Chen, Chun-Hu,Chiang, Chao-Ming
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supporting information
p. 9291 - 9294
(2016/07/25)
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- Ga[OSi(OtBu)3]3·THF, a thermolytic molecular precursor for high surface area gallium-containing silica materials of controlled dispersion and stoichiometry
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The molecular precursor tris[(tri-tert-butoxy)siloxy]gallium, as the tetrahydrofuran adduct Ga[OSi(OtBu)3]3·THF (1), was synthesized via the salt metathesis reaction of gallium trichloride with NaOSi(OtBu)3. This complex serves as a model for isolated gallium in a silica framework. Complex 1 decomposes thermally in hydrocarbon solvent, eliminating isobutylene, water, and tert-butanol to generate high surface area gallium-containing silica at low temperatures. When thermal decomposition was performed in the presence of P-123 Pluronic as a templating agent the generated material displayed uniform vermicular pores. Textural mesoporosity was evident in untemplated material. Co-thermolysis of 1 with HOSi(OtBu)3 in the presence of P-123 Pluronic led to materials with Ga : Si ratios ranging from 1 : 3 to 1 : 50, denoted UCB1-GaSi3, UCB1-GaSi10, UCB1-GaSi20 and UCB1-GaSi50. After calcination at 500 °C these materials exhibited decreasing surface areas and broadening pore distributions with increasing silicon content, indicating a loss of template effects. The position and dispersion of the gallium in UCB1-GaSi materials was investigated using 71Ga MAS-NMR, powder XRD, and STEM/EDS elemental mapping. The results indicate a high degree of gallium dispersion in all samples, with gallium oxide clusters or oligomers present at higher gallium content.
- Dombrowski, James P.,Johnson, Gregory R.,Bell, Alexis T.,Tilley, T. Don
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p. 11025 - 11034
(2016/07/15)
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- The feeding at the same time containing butene dimerization and hydrated method (by machine translation)
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The present invention provides a mixed butene by acid catalysts containing hydrocarbon feed of manufacturing and method of the oligomer at the same time. Furthermore, embodiments of the present invention also provides the preparation of the mixed olefin containing the alcohol and the oligomer process for the preparation of the fuel composition, in certain embodiments, the catalyst can include two-phase catalyst system, the catalyst system includes a water-soluble acid catalyst and solid acid catalyst. (by machine translation)
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Paragraph 0071-0077
(2017/03/22)
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- Cobalt-Catalyzed Hydrogenation of Esters to Alcohols: Unexpected Reactivity Trend Indicates Ester Enolate Intermediacy
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The atom-efficient and environmentally benign catalytic hydrogenation of carboxylic acid esters to alcohols has been accomplished in recent years mainly with precious-metal-based catalysts, with few exceptions. Presented here is the first cobalt-catalyzed hydrogenation of esters to the corresponding alcohols. Unexpectedly, the evidence indicates the unprecedented involvement of ester enolate intermediates. Getting involved: The atom-efficient and environmentally benign catalytic hydrogenation of carboxylic acid esters to alcohols has been accomplished in recent years mainly with precious-metal-based catalysts. Presented here is the first cobalt-catalyzed hydrogenation of esters to alcohols. Unexpectedly, the evidence indicates the unprecedented involvement of ester enolate intermediates.
- Srimani, Dipankar,Mukherjee, Arup,Goldberg, Alexander F. G.,Leitus, Gregory,Diskin-Posner, Yael,Shimon, Linda J. W.,Ben David, Yehoshoa,Milstein, David
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supporting information
p. 12357 - 12360
(2015/10/12)
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- Reduced graphene oxide coupled CdS/CoFe2O4 ternary nanohybrid with enhanced photocatalytic activity and stability: a potential role of reduced graphene oxide as a visible light responsive photosensitizer
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We report the coupling of a CdS/CoFe2O4 (CdS/CFO) core/shell nanorod heterostructure onto the 2D platform of reduced graphene oxide (RGO) sheets by a facile soft chemical route. Intimate interfacial contact between CdS, CFO and RGO is achieved in the synthesis. The CdS/CFO/RGO nanohybrid exhibits an enhanced photocatalytic activity for the degradation of methylene blue under visible light irradiation. In addition to enhanced photocatalytic activity, this trio-coupled nanocomposite exhibits enhanced photostability and is magnetically separable from an aqueous solution due to the presence of CFO in the composite nanostructure and thus can be used for repeated operations of the photocatalytic process. A mechanism for the enhanced photocatalytic activity of the CdS/CFO/RGO has been proposed where the RGO in the ternary nanocomposite serves as a visible light responsive photosensitizer. Our present work indicates that the careful choice of a semiconductor core-shell nanostructure and its coupling with reduced graphene oxide has great potential in the design of efficient and stable visible light responsive photocatalytic materials.
- Singh, Simrjit,Khare, Neeraj
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p. 96562 - 96572
(2015/11/24)
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- Reductive cleavage of inert aryl C-O bonds to produce arenes
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Reductive cleavage of the aryl C-O bonds in various phenolic compounds and aryl ethers was achieved using LiAlH4 combined with KOtBu and without any other catalysts or additives, solely producing arenes in high yields.
- Xu, Huanjun,Yu, Bo,Zhang, Hongye,Zhao, Yanfei,Yang, Zhenzhen,Xu, Jilei,Han, Buxing,Liu, Zhimin
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supporting information
p. 12212 - 12215
(2015/07/27)
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- METHODS AND SYSTEMS FOR PRODUCING ALCOHOLS AND AMIDES FROM CARBON DIOXIDE
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Methods and systems for producing butanol from carbon dioxide, and water are disclosed. In one embodiment, a method of producing butanol from carbon dioxide and water involves contacting carbon dioxide with a reaction mixture containing water and a catalyst, and heating the carbon dioxide and reaction mixture by fluctuating magnetic field. In some embodiments, the catalyst used may be FeAl2O3.
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Paragraph 0036; 0038
(2015/10/05)
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