- Marine natural products: highly functionalized steroids (12β-hydroxy-24-norcholesta-1,4,22-trien-3-one and 12β-acetoxy-24-norcholesta-1,4,22-trien-3-one) from sea raspberry, Gersemia rubiformis
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Two new C26 steroid Δ1,4-dien-3-ones 5 and 6 wit 12β oxygen functions have been isolated from the soft coral Gersemia rubiformis and their structures elucidated from their spectral data and chemical transformations.
- Kingston, John F.,Fallis, Alex G.
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- Kinetic and mechanistic study of the oxidative deamination and decarboxylation of L-valine by alkaline permanganate
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The kinetics of the oxidation of L-valine, (L-Val) by permanganate in aqueous alkaline medium at a constant ionic strength of 0.50 mol · dm-3 was studied spectrophotometrically. The reaction is of first order in [permanganate ion] and of fractional order in both [L-Val] and [alkali]. Addition of products has no significant effect on the reaction rate. However, increasing ionic strength and decreasing dielectric constant of the medium increase the rate. The oxidation process in alkaline medium has been shown to proceed via two paths, one involving the interaction of L-valine with permanganate ion in a slow step to yield the products, and the other path the interaction of alkali with permanganate ion to give manganate. Some reaction constants involved in the mechanism were determined; calculated and observed rate constants agree excellently. The activation parameters were computed with respect to the slow step of the mechanism.
- Harihar, Abdulazizkhan L.,Kembhavi, Mohammadsaleem R.,Nandibewoor, Sharanappa T.
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- Catalytic dehydration of 2,3-butanediol over P/HZSM-5: Effect of catalyst, reaction temperature and reactant configuration on rearrangement products
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As a type of important bio-based vicinal diol, 2,3-butanediol could be transformed into methyl ethyl ketone and 2-methyl propanal through a pinacol rearrangement mechanism under acid catalysis conditions. In this paper, a series of P/HZSM-5 (Si/Al = 360) samples with various phosphate contents were prepared and tested via the catalytic transformation of 2,3-butanediol, with particular focus on the effect of phosphate content on the ratio of methyl ethyl ketone to 2-methyl propanal. The catalyst structures were studied using several physico-chemical methods such as XRD, N2 sorption, NH3-TPD and FT-IR. At 180 °C, the ratio of methyl ethyl ketone to 2-methyl propanal increased from 5.1 to 37.5 when the content of phosphate increased from 0.5 to 8.0. When the reaction temperature increased from 180 °C to 300 °C over 4% P2O5/HZSM-5, the ratio of methyl ethyl ketone to 2-methyl propanal decreased from 15.6 to 2.5. The configuration of 2,3-butanediol would affect the conversion but not the selectivity. The characterization results demonstrated that the phosphate modification of HZSM-5 could not only reduce the strong and medium acid sites but also produce new weak acid sites. Strong acid sites and high reaction temperatures could promote the formation of 2-methyl propanal through methyl migration via carboniums. Based on these results, a possible surface reaction model was proposed.
- Zhao, Jinbo,Yu, Dinghua,Zhang, Wengui,Hu, Yi,Jiang, Ting,Fu, Jie,Huang, He
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- Efficient dehydration of bio-based 2,3-butanediol to butanone over boric acid modified HZSM-5 zeolites
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The dehydration of bio-based 2,3-butanediol provides an alternative green way to produce butanone, which is mainly produced through the dehydrogenation of butanol in industry. In this research, the effect of the framework Si/Al ratio on 2,3-butanediol dehydration over HZSM-5 zeolites (Si/Al = 38-360) was investigated. HZSM-5(360) was further modified with boric acid, and the influence of the loading amount of boric acid on the dehydration performance was studied. The results showed that high Si/Al ratio was beneficial to low-temperature activation of 2,3-butanediol and the methyl migration to 2-methyl propanal. 1.0%B/HZSM-5(360) not only showed best performance at 180°C but also kept stable activities between 180-300°C with a high LHSV 2.4 h-1. According to the characterization results, excellent performance over HZSM-5(360) was due to the highest amount of strong acidic sites (1.1674 mmol g-1) attributed to H-bonded hydroxyl groups, normally silanols. Coexistence of more effective extraframework B-OH species and retained silanols were responsible for the promotion of catalytic performance over 1.0%B/HZSM-5(360).
- Zhang, Wengui,Yu, Dinghua,Ji, Xiaojun,Huang, He
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- Generation of Simple Enols in Aqueous Solution from Alkali Metal Enolates. Some Chemistry of Isobutyraldehyde Enol
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The enol isomer of isobutyraldehyde was generated in aqueous solution by reaction of its lithium and potassium enolates with water and of the trimethylsilyl enol ether with fluoride ion, and rates of ketonization of the enol were measured in HCl, DCl (in D2O), and NaOH solutions and in CNCH2CO2H, HCO2H, CH3CO2H, CH2ClPO3H-, and H2PO4- buffers.Rates of enolization of isobutyraldehyde were also determined, by iodine scavenging, in HClO4 and NaOH solutions.The reaction rates in HCl and NaOH give two independent estimates of the keto-enol equilibrium constant for isobutyraldehyde in aqueous solution at 25 deg C, which are in good agreement with each other and whose average is KE = (1.37 +/- 0.09)*1E-4, pKE = 3.86 +/- 0.03.The ketonization rates in NaOH solution also provide an estimate of the acidity constant of isobutyraldehyde enol ionazing as an oxygen acid, KaE = (2.37 +/- 0.14)*1E-12 M, pKaE = 11.63 +/- 0.03, which, when combined with KE, gives the acidity constant of the keto form of isobutyraldehyde ionizing as a carbon acid, KaK = (3.23 +/- 0.29)*1E-16 M, pKaK = 15.49 +/- 0.04.The ketonization reaction in buffer solutions shows both general-acid and general-base catalysis, consistent with two parallel reaction paths involving rate-determing β-carbon protonation of both enol and enolate ion.Analysis of the data in terms of this scheme shows enolate to be 1E8 times more reactive than enol.Arguments are advanced to the effect that all of the present data are consistent with stepwise reaction mechanisms and do not require a concerted reaction path.
- Chiang, Y.,Kresge, A. J.,Walsh, P. A.
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- Ti-SBA-15 supported Cu-MgO catalyst for synthesis of isobutyraldehyde from methanol and ethanol
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Ti-SBA-15 supported Cu and MgO catalysts were prepared and used for the first time in the one-step conversion of methanol and ethanol to isobutyraldehyde (IBA). The results show that the loadings of Cu and MgO, and catalyst calcination temperature have strong effects on the catalyst activity. A high yield of IBA, 32.7%, and high ethanol conversion, 96.6%, were achieved at 360 °C with WHSV of 3.0 mL (g-1 h-1) on the catalyst calcined at 400 °C when the loadings of Cu and Mg were 20.0 wt% and 6.5 wt%, respectively. The physicochemical properties of the catalysts were analyzed by various techniques including XRD, N2 adsorption and desorption, FT-IR, H2-TPR, CO2-TPD and XPS. The ordered mesoporous structure of the catalysts was retained with the introduction of CuO and MgO. The size of CuO particles on the catalysts was retained though they suffered from a varied calcination temperature. H2-TPR measurements revealed that the increase of calcination temperature from 400 °C to 700 °C resulted in the decrease of basicity of the catalysts, and enhanced the interaction between the Cu and Mg species and the support. The results from XPS analysis indicated that the binding energy of Cu 2p was increased with the introduction of MgO, while the increased calcination temperature easily resulted in the decrease of Cu content on the catalyst surface due to probable migration of Cu species into internal pores or their incorporation into the framework of the Ti-SBA-15 support.
- Zhang, Junfeng,Wu, Yingquan,Li, Li,Wang, Xiaoxing,Zhang, Qingde,Zhang, Tao,Tan, Yisheng,Han, Yizhuo
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- Os(VIII)/Ru(III) catalysed oxidation of l-valine by Ag(III) periodate complex in aqueous alkaline medium: A comparative kinetic study
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The kinetics of osmium(VIII) (Os(VIII)) and ruthenium(III) (Ru(III)) catalysed oxidation of l-valine (l-val) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 25 °C and a constant ionic strength of 0.006 mol dm-3 was studied spectrophotometrically. The stoichiometry is the same in both the catalysed reactions, i.e., [l-val]:[DPA] = 1:1. The reaction is of first order in [Os(VIII)], [Ru(III)], and [DPA] and has less than unit order in [l-val] and negative fractional order in [OH-]. Added periodate had no effect on rate of reaction. The products were identified by spot test and characterized by spectral studies. The catalytic constant (K C) was also calculated for both catalysed reactions at different temperatures. The activation parameters with respect to slow step of the mechanisms were computed and discussed and thermodynamic quantities were also determined. It has been observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The probable active species of catalyst and oxidant have been identified. Graphical Abstract: The kinetics of osmium(VIII) (Os(VIII)) and ruthenium(III) (Ru(III)) catalysed oxidation of l-valine (l-val) by diperiodatoargentate(III) (DPA) in aqueous alkaline medium at 25 °C and a constant ionic strength of 0.006 mol dm-3 was studied spectrophotometrically. Suitable mechanisms were proposed and active species of DPA, Os(VIII) and Ru(III) were identified. The main products were identified and characterized by spectral studies.
- Malode, Shweta J.,Shetti, Nagaraj P.,Nandibewoor, Sharanappa T.
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- Kinetics of oxidation of L-valine by a copper(III) periodate complex in alkaline medium
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The kinetics of oxidation of L-valine by a copper(III) periodate complex was studied spectrophotometrically. The inverse second-order dependency on [OH-] was due to the formation of the protonated diperiodatocuprate(III) complex ([Cu(H3IO6) 2]-) from [Cu(H2IO6) 2]3-. The retarding effect of initially added periodate suggests that the dissociation of copper(III) periodate complex occurs in a pre-equilibrium step in which it loses one periodate ligand. Among the various forms of copper(III) periodate complex occurring in alkaline solutions, the monoperiodatocuprate(III) appears to be the active form of copper(III) periodate complex. The observed second-order dependency of [L-valine] on the rate of reaction appears to result from formation of a complex with monoperiodatocuprate(III) followed by oxidation in a slow step. A suitable mechanism consistent with experimental results was proposed. The rate law was derived as: (Equation presented) The temperature effect on the rate of reaction was also studied. The activation parameters of the reaction Ea, ΔH#, ΔS#, ΔG#, and log 10 A are 49 ± 2 kJ·mol-1, 47.5 ± 2 kJ·mol-1, -49 ± 2 J·K -1·mol-1, 62 ± 3 kJ·mol-1 and 6.0 ± 0.1, respectively. Springer Science+Business Media, LLC 2012.
- Sharanabasamma,Angadi, Mahantesh A.,Salunke, Manjalee S.,Tuwar, Suresh M.
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- Detailed structure-function correlations of bacillus subtilis acetolactate synthase
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Isobutanol is deemed to be a next-generation biofuel and a renewable platform chemical.[1] Non-natural biosynthetic pathways for isobutanol production have been implemented in cell-based and in vitro systems with Bacillus subtilis acetolactate synthase (AlsS) as key biocatalyst.[2-6] AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg2+ as cofactors. AlsS also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol. Our phylogenetic analysis suggests that the ALS enzyme family forms a distinct subgroup of ThDP-dependent enzymes. To unravel catalytically relevant structure-function relationships, we solved the AlsS crystal structure at 2.3 ? in the presence of ThDP, Mg2+ in a transition state with a 2-lactyl moiety bound to ThDP. We supplemented our structural data by point mutations in the active site to identify catalytically important residues.
- Sommer, Bettina,Von Moeller, Holger,Haack, Martina,Qoura, Farah,Langner, Clemens,Bourenkov, Gleb,Garbe, Daniel,Loll, Bernhard,Brück, Thomas
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- Oxidation of propylene and isobutylene in a reactor with barrier discharge
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The oxidation of propylene and isobutylene in barrier-discharge plasma in the presence of octane was studied. The possible reaction mechanism was considered.
- Kudryashov,Ryabov,Sirotkina,Shchegoleva
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- ALDEHYDE GENERATION VIA ALKENE HYDROFORMYLATION
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Aldehyde generation includes providing a first input stream, a second input, and an alkene substrate to a reactor system. The first input stream includes a catalyst, a ligand, and an organic solvent. The second input stream includes a mixture of carbon monoxide (CO) and hydrogen gas (H2). The alkene substrate is in either gaseous form or liquid form, the liquid form of the alkene substrate being provided with the first input stream, the gaseous form of the alkene substrate being provided with the second input stream. The reactor system includes a first reactor and a second reactor, where the second reactor is gas permeable and positioned within the first reactor.
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Paragraph 0083; 0084
(2021/09/26)
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- Catalyst composition for hydroformylation and method of preparing aldehyde using the same
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The present invention relates to a catalyst composition for hydroformylation and a method of preparing an aldehyde using the same. More specifically, the present invention provides a catalyst composition for hydroformylation including a specific phosphite-based ligand and a transition metal compound in a specific amount range, thereby being capable of greatly lowering a use amount of an expensive transition metal compound and exhibiting excellent catalyst activity or stability. In addition, by using the catalyst composition in hydroformylation, excellent reaction efficiency may be provided and iso-aldehyde may be generated in high yield.
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Page/Page column 8-10
(2021/12/02)
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- Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
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Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
- Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
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- SYSTEMS AND METHODS FOR REGIOSELECTIVE CARBONYLATION OF 2,2-DISUBSTITUTED EPOXIDES FOR THE PRODUCTION OF ALPHA,ALPHA-DISUBSTITUTED BETA-LACTONES
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Provided are methods of producing carbonyl compounds (e.g., carbonyl containing compounds) and catalysts for producing carbonyl compounds. Also provided are methods of making polymers from carbonyl compounds and polymers formed from carbonyl compounds. A method may produce carbonyl compounds, such as, for example α,α-disubstituted carbonyl compounds (e.g., α,α-disubstituted β-lactones). The polymers may be produced from α,α-disubstituted β-lactones, which may be produced by a method described herein.
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Paragraph 0082
(2021/01/29)
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- METHOD FOR PREPARING ISOBUTENOL
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The present invention provides a method for preparing isobutanol, which comprises a step of selectively hydrogenating methacrolein in the presence of a catalyst and additives. The preparation method according to the present invention can increase the selectivity of the isobutanol.
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Paragraph 0072-0077; 0080-0081; 0083
(2021/06/15)
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- METHOD FOR PREPARING ISOBUTENOL
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The present invention provides a method for preparing isobutanol, which comprises a step of selectively hydrogenating methacrolein in the presence of a pincer ligand catalyst. The preparation method according to the present invention can increase the selectivity of the isobutanol.
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Paragraph 0052-0053; 0064-0065; 0068-0069
(2021/06/15)
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- METHOD FOR PREPARING ISOBUTENOL
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The present invention provides a method for manufacturing isobutenol comprising a step of selectively hydrogenating methacrolein in the presence of an additive. A manufacturing method according to the present invention can increase the selectivity of isobutenol. In the manufacturing method according to an exemplary embodiment of the present invention, the additive represented by the chemical formula 1 is added to provide isobutenol with high selectivity, and the selective hydrogenation reaction is predominant, so that the amount of a catalyst can be reduced.
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Paragraph 0077; 0088-0091; 0095-0096
(2021/06/15)
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- METHOD FOR PRODUCING CARBONATE DERIVATIVE
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The objective of the present invention is to provide a method for producing a polycarbonate safely and efficiently even without using a base. The method for producing a carbonate derivative according to the present invention is characterized in comprising the step of irradiating a high energy light to a composition comprising the halogenated methane and the hydroxy group-containing compound in the presence of oxygen, wherein a molar ratio of a total usage amount of the hydroxy group-containing compound to 1 mole of the halogenated methane is 0.05 or more.
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Paragraph 0122-0123
(2022/01/04)
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- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- Organic Ligand-Free Hydroformylation with Rh Particles as Catalyst?
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An efficient and organic ligand-free heterogeneous catalytic system for hydroformylation of olefins is highly desirable for both academy and industry. In this study, simple Rh black was employed as a heterogeneous catalyst for hydroformylation of olefins in the absence of organic ligand. The Rh black catalyst showed good catalytic activity for a broad substrate scope including the aliphatic and aromatic olefins, affording the desired aldehydes in good yields. Taking the hydroformylation of ethylene as an example, 86% yield of propanal and TOF of 200 h–1 were obtained, which was superior to the reported homogeneous catalytic systems. In addition, the catalyst could be reused five times without loss of activity under identical reaction conditions, and the Rh leaching was negligible after each cycle.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Wang, Xinzhi,Shi, Feng
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p. 139 - 143
(2020/01/03)
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- DIHYDROXYBIPHENYL COMPOUND, BISPHOSPHITE COMPOUND, CATALYST, PRODUCTION METHOD OF ALDEHYDES, AND PRODUCTION METHOD OF ALCOHOL
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An object of the present invention is to provide a bisphosphite compound giving higher selectivity for the target product with maintaining a high reaction rate. The present invention relates to a dihydroxybiphenyl compound represented by the following formula (1) and a bisphosphite compound represented by the following formula (2): wherein in formulae (1) and (2), each of R1 to R4, R11 to R14, and Z1 to Z4 is the same as defined in the description.
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Paragraph 0170-0172
(2020/07/05)
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- NASICON Catalysts with Composition Na(Cs)1 – 2xMxZr2(PO4)3 for Transformations of Aliphatic Alcohols
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Abstract: The activity of solid electrolytes from the family of Na(Cs)–Mx–Zr phosphates (NZP and CZP) with dopant ions M+2 = Co+2 and Ni+2 synthesized by the sol–gel method is studied in the gas-phase transformations of isopropanol and isobutanol. It is found that the amount of M+2 and its nature, as well as the direction of a change in the catalyst temperature (heating or cooling in the range of 473?693 K), affects the activity of M-NZP and M-CZP. In the transformation of isopropanol, hysteresis of the acetone yield, counter-clockwise (type I) for Co-NZP and clockwise (type II) for Ni-NZP, is observed in the heating–cooling cycles. An increase in the activity of Co-NZP in the cooling mode (type I) is related to a rise in the apparent activation energy of alcohol dehydrogenation under conditions of the formation of new catalytically active sites in the form of a Co+2?Zr+4 → Co+3?Zr+3 ion pair with the oxidized form of M and the reduced form of Zr. Type I hysteresis of the total alcohol conversion is observed in the transformations of isobutanol to olefin and aldehyde over Co(Ni)-CZP. The hysteresis is associated with a decrease in the activation energy of alcohol dehydrogenation. The main reaction over the Co(Ni)-CZP catalysts is the dehydration of alcohol with an increase in the activation energy of the reaction upon cooling, for example, by 53 kJ/mol for Ni0.25-CZP.
- Knyazeva, E. I.,Mikhalenko, I. I.,Pylinina, A. I.
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p. 1176 - 1183
(2020/10/14)
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- Novel Si(II)+and Ge(II)+Compounds as Efficient Catalysts in Organosilicon Chemistry: Siloxane Coupling Reaction ?
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Novel catalytically active cationic Si(II) and Ge(II) compounds were synthesized and isolated in pure form. The Ge(II)+-based compounds proved to be stable against air and moisture and therefore can be handled very easily. All compounds efficiently catalyze the oxidative coupling of hydrosil(ox)anes with aldehydes and ketones as oxidation reagents and simultaneously the reductive ether coupling at very low amounts of 0.01 mol %. Because the catalysts also catalyze the reversible cyclotrimerization of aldehydes, paraldehyde can be used as a convenient source for acetaldehyde in siloxane coupling. It is shown that the reaction is especially suitable to make siloxane copolymers. Moreover, a new fluorine-free weakly coordinating boronate anion, B(SiCl3)4-, was successfully combined with the Si(II) and Ge(II) cations to give the stable catalytically active ion pairs Cp*Si:+B(SiCl3)4-, Cp*Ge:+B(SiCl3)4-, and [Cp(SiMe3)3Ge:+]B(SiCl3)4-.
- Fritz-Langhals, Elke,Kneissl, Sotirios,Piroutek, Phillip,Werge, Sven
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- Catalyst-controlled regioselective carbonylation of isobutylene oxide to pivalolactone
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Poly(pivalolactone) (PPVL) is a crystalline polyester with attractive physical and mechanical properties; however, prohibitively expensive syntheses of pivalolactone have thwarted efforts to produce PPVL on an industrial scale. Therefore, we developed a class of highly regioselective sandwich-type catalysts for the carbonylation of isobutylene oxide. These sterically encumbered complexes install carbon monoxide at the substituted epoxide carbon, generating a high level of contrasteric selectivity (up to >99:1). Further catalyst development improved catalyst solubility and reproducibility while maintaining high regioselectivity. In addition, a dibasic ester solvent extended catalyst lifetimes and suppressed side product formation. This contrasteric carbonylation of isobutylene oxide offers a route to sought-after pivalolactone and, therefore, PPVL.
- Hubbell, Aran K.,Lamb, Jessica R.,Klimovica, Kristine,Mulzer, Michael,Shaffer, Timothy D.,MacMillan, Samantha N.,Coates, Geoffrey W.
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p. 12537 - 12543
(2020/11/10)
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- High iso Aldehyde Selectivity in the Hydroformylation of Short-Chain Alkenes
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The hydroformylation of propene to give predominantly iso-butanal has been achieved; class-leading selectivity is possible even at higher temperatures that deliver fast conversion. Racemic rhodium complexes of bidentate phospholane phosphites derived from tropos-biphenols and unusual solvent systems are the key to the selectivity observed.
- Iu, Leo,Fuentes, José A.,Janka, Mesfin E.,Fontenot, Kevin J.,Clarke, Matthew L.
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supporting information
p. 2120 - 2124
(2019/01/25)
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- A METHOD FOR THE ALDEHYDE BY HYDROFORMYLATION REACTION
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The present invention relates to a method for producing aldehydes by hydroformylation. More specifically, the present invention relates to a method for producing aldehydes which can secure economic efficiency of the process such as reduction of raw material cost and enhancement of productivity by reducing heavy by-products by suppressing aldol reaction of the hydroformylation products when post-treating using a simple, quick, and cheap method and increasing the production amount of aldehydes.(AA) Synthetic gas + olefin(BB) Water(i) Reactor(ii) Distillation apparatus(iii) Fractionation tankCOPYRIGHT KIPO 2019
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Paragraph 0073; 0076-0085; 0090-0103
(2019/04/09)
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- Highly isoselective catalyst for alkene hydroformylation
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Ligands for use with catalyst compositions used in hydroformylation reactions are described herein. The ligands are used with various ester solvents and achieve an increase in isoselectivity with an increase in temperature, an increase in TON with an increase in temperature, and/or will show isoselectivity that is surprisingly high in comparison to the hydroformylation reactions using common solvents.
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Page/Page column 10; 11; 12; 13
(2019/02/07)
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- CATALYSTS FOR CONVERSION OF 2,3-BUTANEDIOL-CONTAINING FERMENTATION MIXTURE TO HYDROCARBONS
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A method for producing one or more hydrocarbon compounds from at least one of 2,3-butanediol, acetoin, and ethanol, the method comprising contacting said at least one of 2,3-butanediol, acetoin, and ethanol with a catalyst at a temperature of at least 100° C. and up to 500° C. to result in said 2,3-butanediol, acetoin, and/or ethanol being converted to said one or more hydrocarbon compounds, wherein said catalyst is either: (i) a catalyst comprising nanoparticles composed of (a) a first metal oxide selected from the group consisting of zirconium oxide, cerium oxide, titanium oxide, and lanthanum oxide, and (b) a main group metal oxide; or (ii) a catalyst comprising a zeolite loaded with at least one metal selected from the group consisting of copper, silver, nickel, palladium, platinum, rhodium, and ruthenium in an amount of 1-30 wt % by weight of the zeolite.
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Paragraph 0035-0041
(2019/02/25)
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- 2,3-Butanediol dehydration catalyzed by silica-supported alkali phosphates
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Characterization of acid-base centers and catalytic dehydration of 2,3-butanediol (BDO) was performed over a wide range of silica-supported alkali phosphates (M_P/SiO2; M = Na, K, Cs; M:P = 0.5–3 mol:mol). Selectivity to 1,3-butadiene (BD) and 3-butene-2-ol (3B2OL) formed by elimination correlates with the densities of conjugated acid-base pairs and increases in the order Na ??M+ moieties. Isolated Br?nsted acid centers are probably silica grafted phosphoric acid molecules at low M/P and –PO(OH)2 end groups of oligophosphates at M/P > 1.5. Deactivation rate increases with the increase of M/P ratio in order Na K Cs. Deactivation patterns imply that sites responsible for elimination are active in dehydrative epoxidation. Dehydration of 3B2OL smoothly proceeds to BD, but the catalysts deactivate faster compared to BDO dehydration.
- Kim, Wooyoung,Shin, Wookyun,Lee, Kyoung Jun,Cho, YongSeok,Kim, Hyung Soon,Filimonov, Igor N.
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p. 148 - 163
(2018/11/26)
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- Vapor-phase catalytic dehydration of butanediols to unsaturated alcohols over yttria-stabilized zirconia catalysts
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Vapor-phase catalytic dehydration of butanediols (BDOs) such as 1,3-, 1,4-, and 2,3-butanediol was investigated over yttria-stabilized tetragonal zirconia (YSZ) catalysts as well as monoclinic zirconia (MZ). BDOs were converted to unsaturated alcohols with some by-products over YSZ and MZ. YSZ is superior to MZ for these reactions in a view point of selective formation of unsaturated alcohols. Calcination temperature of YSZ significantly affected the products selectivity as well as the conversion of BDOs: high selectivity to unsaturated alcohols was obtained over the YSZ calcined at high temperatures over 800 °C. In the conversion of 1,4-butanediol at 325 °C, the highest 3-buten-1-ol selectivity of 75.3% was obtained over the YSZ calcined at 1050 °C, whereas 2,3-butanediol was less reactive than the other BDOs. In the dehydration of 1,3-butanediol at 325 °C, in particular, it was found that a YSZ catalyst with a Y2O3 content of 3.2 wt.% exhibited an excellent stable catalytic activity: the highest selectivity to unsaturated alcohols such as 2-buten-1-ol and 3-buten-2-ol over 98% was obtained at a conversion of 66%. Structures of active sites for the dehydration of 1,3-butanediol were discussed using a crystal model of tetragonal ZrO2 and a probable model structure of active site was proposed. The well-crystalized YSZ inevitably has oxygen defect sites on the most stable surface of tetragonal ZrO2 (101). The defect site, which exposes three cations such as Zr4+ and Y3+, is surrounded by six O2? anions. The selective dehydration of 1,3-butanediol to produce 3-buten-2-ol over the YSZ could be explained by tridentate interactions followed by sequential dehydration: the position-2 hydrogen is firstly abstracted by a basic O2? anion and then the position-1 hydroxyl group is subsequently or simultaneously abstracted by an acidic Y3+ cation. Another OH group at position 3 plays an important role of anchoring 1,3-butanediol to the catalyst surface. Thus, the selective dehydration of 1,3-butanediol could proceed via the speculative base-acid-concerted mechanism.
- Ohtsuka, Shota,Nemoto, Takuma,Yotsumoto, Rikako,Yamada, Yasuhiro,Sato, Fumiya,Takahashi, Ryoji,Sato, Satoshi
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-
- Production of 1,3-butadiene in one step catalytic dehydration of 2,3-butanediol
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Catalysts able to selectively dehydrate 2,3-butanediol into butadiene have been designed. These catalysts, based on rare-earth orthophosphates showed that 58% selectivity to butadiene could be obtained at total conversion at only 300 °C, and were relatively stable. While the deactivation could be delayed by addition of water to the gas feeds, it could not be avoided and a regeneration was necessary. This regeneration was achieved by a simple heat treatment under air for a few hours at 450 °C. All results showed that Lewis acid sites corresponding to the rare earth cations are involved in the dehydration of 2,3-butanediol into butadiene. This dehydration occurs with the intermediate formation of 3-buten-2ol, probably over acid-base concerted sites and the subsequent dehydration of 3BDOL to butadiene over weak Br?nsted acid sites. All types of sites appear present on the catalysts surface and distributed in a relatively optimal way.
- Nguyen,Matei-Rutkovska,Huchede,Jaillardon,Qingyi,Michel,Millet
-
-
- Metal-free hypervalent iodine/TEMPO mediated oxidation of amines and mechanistic insight into the reaction pathways
-
A highly efficient metal free approach for the oxidation of primary and secondary amines to their corresponding aldehydes and ketones using PhI(OAc)2 in combination with a catalytic amount of TEMPO as an oxidizing agent is described. This protocol is rapid and provides diverse products under milder reaction conditions in excellent yields. In addition, the mechanistic study is well demonstrated by spectroscopic methods.
- Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 32055 - 32062
(2018/09/29)
-
- Rhodium Pyrrolylphosphine Complexes as Highly Active and Selective Catalysts for Propene Hydroformylation: The Effect of Water and Aldehyde on the Reaction Regioselectivity
-
The hydroformylation of propene catalyzed by Rh(acac)(CO)2 (acac=acetylacetonate) with a 13-fold excess of N-pyrrolylphosphine ligands PPyr3, PPh2Pyr, or PPh(Pyr)2 (Pyr=NC4H4) was investigated under a pressure of 15 bar (propene/H2/CO=5:5:5) at 80 °C. The N-pyrrolylphosphine ligands facilitated an excellent regioselectivity towards n-butanal aldehyde, significantly better than PPh3 and PCy3 under the same conditions. In the presence of the strongest π-acceptor, PPyr3, the linear-to-branched aldehyde (l/b) ratio was 8.6, which increased to 27.1 if water was added to the system. The application of a pure aldehyde as a solvent instead of toluene caused a significant increase in the aldehyde yield but with a decreased l/b ratio (2.9–7.6). The regioselectivity parameter l/b increased to 19.3 after the introduction of water as a cosolvent.
- Mieczyńska, Ewa,Grzybek, Ryzard,Trzeciak, Anna M.
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p. 305 - 310
(2017/11/16)
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- Highly isoselective catalyst for alkene hydroformylation
-
Ligands for use with catalyst compositions used in hydroformylation reactions are described herein. The ligands are used with various octofluorotoluene or hydrocarbon solvents and achieve an increase in isoselectivity with an increase in temperature, an increase in TON with an increase in temperature, and/or will show isoselectivity that is surprisingly high in comparison to the hydroformylation reactions using common solvents.
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Page/Page column 10-14
(2019/01/04)
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- O→S Relay Deprotection: A General Approach to Controllable Donors of Reactive Sulfur Species
-
Reactive sulfur species (RSS) are biologically important molecules. Among them, H2S, hydrogen polysulfides (H2Sn, n>1), persulfides (RSSH), and HSNO are believed to play regulatory roles in sulfur-related redox biology. However, these molecules are unstable and difficult to handle. Having access to their reliable and controllable precursors (or donors) is the prerequisite for the study of these sulfur species. Reported in this work is the preparation and evaluation of a series of O-silyl-mercaptan-based sulfur-containing molecules which undergo pH- or F?-mediated desilylation to release the corresponding H2S, H2Sn, RSSH, and HSNO in a controlled fashion. This O→S relay deprotection serves as a general strategy for the design of pH- or F?-triggered RSS donors. Moreover, we have demonstrated that the O-silyl groups in the donors could be changed into other protecting groups like esters. This work should allow the development of RSS donors with other activation mechanisms (such as esterase-activated donors).
- Kang, Jianming,Xu, Shi,Radford, Miles N.,Zhang, Wenjia,Kelly, Shane S.,Day, Jacob J.,Xian, Ming
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supporting information
p. 5893 - 5897
(2018/04/25)
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- Generation of methylene by the liquid phase oxidation of isobutene with nitrous oxide
-
The application of nitrous oxide as an alternative oxidant provides new opportunities for selective oxidation of olefins. Here, we studied for the first time the thermal oxidation of isobutene with N2O in the liquid phase. The study revealed that the oxidation proceeds via 1,3-dipolar cycloaddition of N2O to the C[dbnd]C bond by two routes forming unstable 4,5-dihydro-[1,2,3]-oxadiazole intermediates. The main route (the contribution of 91%) includes the addition of the N2O oxygen to the second carbon atom in olefin. In this case, the oxadiazole decomposes with the C–C bond cleavage yielding acetone, methylene (:CH2), and N2. The methylene then readily reacts with isobutene and benzene (solvent). The minor route involves the addition of the N2O oxygen to the first carbon atom and the oxadiazole decomposition with a hydrogen shift leading to isobutanal and N2. The main distinctive feature of the studied reaction is the formation of methylene in high yield.
- Semikolenov, Sergey,Ivanov, Dmitry,Babushkin, Dmitry,Malykhin, Sergey,Kharitonov, Alexander,Dubkov, Konstantin
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supporting information
p. 3589 - 3595
(2018/05/24)
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- About the First Stable α-Lactam with a Secondary Alkyl Substituent in Position Three: 3-Isopropyl-1-triphenylmethylaziridinone
-
A three-step synthesis, characterization, pyrolysis, the thermal decomposition products, and three reactions of 3-isopropyl-1-triphenylmethylaziridinone are described. This is the first stable α-lactam with a secondary alkyl substituent in position three.
- Benitez, Michael,Wang, Yun Dan,Lengyel, Istvan,Fitzsimmons, Matthew,Cesare, Victor
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p. 2877 - 2882
(2018/10/24)
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- Method for producing aldehydes through olefin hydroformylation reaction
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The invention relates to a method for producing aldehydes through an olefin hydroformylation reaction, and mainly solves the problems that in the prior art, olefins or olefins containing side-chain radicals are poor in reactivity, and a catalytic system is not stable under weak acidic conditions. The method for producing the aldehydes through the olefin hydroformylation reaction comprises the step that under the conditions that the temperature is 60-130 DEG C and the reaction pressure is 1.0-6.0 MPa, an aldehyde serves as a solvent, olefin hydroformylation is catalyzed with a rhodium compound, a phosphorus compound containing o-methyl and phenyl groups, a hard base pentavalent phosphorus-containing oxide and a bidentate phosphite ester compound to synthesize the aldehydes; according to the technical scheme, the olefin is at least one of isobutene, cis-2-butene, 2,5-dihydrofuran, 1-butene, propylene and ethylene, the problem is well solved, and the olefin can be used for the process of producing the aldehydes through the olefin hydroformylation reaction.
- -
-
Paragraph 0035; 0036
(2017/04/03)
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- Catalysts and processes for producing aldehydes
-
Use of a unique supramolecular assembly of a tris-pyridylphosphine ligand and a metal centered porphyrin complex modified with a lactone functional group was shown to have improved selectivities to branched aldehydes via rhodium catalyzed hydroformylation of unsubstituted linear alpha olefins such as propylene and 1-octene. The addition of potassium salts was also shown to increase the activity of the lactone modified porphyrin-based catalyst while maintaining similar branched aldehyde selectivities for propylene hydroformylation.
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Page/Page column 9; 10
(2017/06/02)
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- HYDROFORMYLATION PROCESS USING CATALYST COMPOSITION COMPRISING PHOSPHITE LIGANDS
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The present invention relates to a hydroformylation process of olefin-based compounds using a catalyst composition containing a phosphorus-based ligand, and a catalyst composition. Specifically, the present invention relates to a hydroformylation process of olefin-based compounds and a catalyst composition, wherein the process comprises a step of reacting an olefin-based compound with synthetic gases (CO/H_2) of carbon monoxide and hydrogen in the presence of a catalyst composition containing 1-8 wt% of phosphite ligands having a symmetry axis so as to produce aldehyde. During the reaction, a reaction temperature is 70-90anddeg;C, a reaction pressure is 5-25 bar, and a normal/iso (N/I) selectivity of the synthesized aldehyde is lower than 2.0. Accordingly, the present invention can provide a hydroformylation process of olefin-based compounds using a catalyst composition which reduces an N/I selectivity of aldehydes produced by hydroformylation of an olefin-based compound and exhibits superior catalytic activity and stability. Additionally, the present invention can provide a catalyst composition.COPYRIGHT KIPO 2017
- -
-
Paragraph 0051; 0052
(2017/09/02)
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- Tuning the Porphyrin Building Block in Self-Assembled Cages for Branched-Selective Hydroformylation of Propene
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Unprecedented regioselectivity to the branched aldehyde product in the hydroformylation of propene was attained on embedding a rhodium complex in supramolecular assembly L2, formed by coordination-driven self-assembly of tris(meta-pyridyl)phosphine and zinc(II) porpholactone. The design of cage L2 is based on the ligand-template approach, in which the ligand acts as a template for cage formation. Previously, first-generation cage L1, in which zinc(II) porphyrin units were utilized instead of porpholactones, was reported. Binding studies demonstrate that the association constant for the formation of second-generation cage L2 is nearly an order of magnitude higher than that of L1. This strengthened binding allows cage L2 to remain intact in polar and industrially relevant solvents. As a consequence, the unprecedented regioselectivity for branched aldehyde products can be maintained in polar and coordinating solvents by using the second-generation assembly.
- Wang, Xiaowu,Nurttila, Sandra S.,Dzik, Wojciech I.,Becker, René,Rodgers, Jody,Reek, Joost N. H.
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supporting information
p. 14769 - 14777
(2017/09/06)
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- Method for synthesis of aldehydes by hydroformylation of alkenes on one same set of production equipment
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The invention relates to a method for synthesis of aldehydes by hydroformylation of alkenes on one same set of production equipment, and mainly aims to solve the problem of reaction activity decreasing and catalyst poisoning caused by cross of catalyst ligands in the switching process of different catalysts in the prior art. According to the method, at 60-130 DEG C under the reaction pressure of 1.0-6.0MPa in the switching process of different hydroformylation catalysts, a ruthenium compound is added, so that a rhodium compound, a phosphine compound and a bidentate phosphite composition can catalyze the hydroformylation for synthesis of different aldehydes; the alkenes are at least one of isobutene, cis-2-Butene, trans-2-Butene, 1-Butene, propylene and ethylene, by use of the method, the problem of reaction activity decreasing and catalyst poisoning can be well solved, and the method can be used for synthesis of the aldehydes by hydroformylation of the alkenes on one same set of production equipment.
- -
-
Paragraph 0034; 0035
(2017/08/26)
-
- Catalyst composition for hydroformylation reaction and method of hydroformylating olefin using the same
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Disclosed are a catalyst composition and a method of hydroformylating olefin using the same, which may maintain catalyst activity through improvement of catalyst stability and reduce a use amount of a ligand while improving selectivity to iso-aldehyde, by using a specific ligand to a transition metal catalyst and a ligand stabilizer together in hydroformylation of olefin.
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Page/Page column 6; 7
(2017/05/02)
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- Direct synthesis of isobutyraldehyde from methanol and ethanol on Cu-Mg/Ti-SBA-15 catalysts: The role of Ti
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Herein, Cu-Mg/Ti-SBA-15 catalysts were prepared through the modification of Cu and Mg to mesoporous Ti-SBA-15 zeolites with different Ti/Si ratios and used for the synthesis of isobutyraldehyde (IBA) from methanol and ethanol. The catalysts were characterized via various techniques including XRF, XRD, TEM, N2 sorption, CO2-TPD, FT-IR, and XPS. With an increase in Ti content, CuO was well dispersed accordingly, and the amounts and strength of the basic sites were reduced. However, an excess introduction of Ti led to the accumulation of single TiO2 crystals, inducing a decrease in the surface area and a deviation from the regular pattern such that the binding energies of Cu 2p, Mg 2p, and Si 2p shifted to lower values. This precisely affected the catalytic behaviors of the prepared catalysts synergistically. The catalyst stability was improved with the increasing Ti content accordingly, and over the catalyst with a Ti/Si ratio = 4/15, the IBA selectivity, after 24 h reaction, could still reach 25%, which was the best durability ever reported for IBA synthesis from methanol and ethanol. The catalytic performance test conducted using a regenerated catalyst and IR measurement of the spent catalyst indicated that carbon deposition on the catalyst surface could be depressed to some extent with the increasing Ti content.
- Zhang, Junfeng,Zhang, Meng,Wang, Xiaoxing,Zhang, Qingde,Song, Faen,Tan, Yisheng,Han, Yizhuo
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p. 9639 - 9648
(2017/09/18)
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- Hydrogen-Free Gas-Phase Deoxydehydration of 2,3-Butanediol to Butene on Silica-Supported Vanadium Catalysts
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The gas-phase deoxydehydration of 2,3-butanediol to butene was investigated in a plug flow reactor over SiO2-supported vanadium oxide, γ-alumina, P/ZSM-5, and MgO catalysts with acid/base sites of varying strengths. 5 wt % vanadium on SiO2 (i.e., 5V/SiO2) showed the best performance with 100 % conversion and up to 45.2 % butene selectivity. The combination of weak acid sites and polymeric VOx surface species provided the 5V/SiO2 catalyst with bifunctional capabilities to achieve both dehydration and transfer hydrogenation, which allowed it to catalyze the deoxydehydration of 2,3-butanediol to butene even in the absence of H2. As 2,3-butanediol is a common yet underutilized biomass product, this reaction may provide a viable route for a biomass-to-chemicals application for 2,3-butanediol.
- Kwok, Kelvin Mingyao,Choong, Catherine Kai Shin,Ong, Daniel Sze Wei,Ng, Joy Chun Qi,Gwie, Chuandayani Gunawan,Chen, Luwei,Borgna, Armando
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p. 2443 - 2447
(2017/07/12)
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- METHOD OF PREPARING 1,3-BUTADIENE AND METHYL ETHYL KETONE FROM 2,3-BUTANEDIOL USING ADIABATIC REACTOR
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Disclosed is a method of preparing 1,3-butadiene and methyl ethyl ketone from 2,3-butanediol, including: a) providing a plurality of adiabatic reactors, which include a catalyst bed for dehydrating 2,3-butanediol, without a heat transfer medium, and are connected in series; b) introducing a stream including 2,3-butanediol at a temperature ranging from 200° C. to 400° C. into a first adiabatic reactor among the plurality of adiabatic reactors; c) dehydrating the 2,3-butanediol so as to be converted into 1,3-butadiene and methyl ethyl ketone and discharging a product stream including 1,3-butadiene and methyl ethyl ketone; d) heating the discharged product stream to 200° C. to 400° C.; and e) introducing the heated product stream into a second adiabatic reactor so that 2,3-butanediol is further dehydrated and converted into 1,3-butadiene and methyl ethyl ketone and then discharging the product stream including 1,3-butadiene and methyl ethyl ketone.
- -
-
Paragraph 0079; 0083
(2018/01/04)
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- Vapor-phase catalytic dehydration of 2,3-butanediol to 3-buten-2-ol over ZrO2 modified with alkaline earth metal oxides
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Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) to produce 3-buten-2-ol (3B2OL) was investigated over several monoclinic ZrO2 (m-ZrO2) catalysts modified with alkaline earth metal oxides (MOs), such as SrO, BaO, and MgO, to compare with the previously reported CaO/m-ZrO2. It was found that these modifiers enhanced the 3B2OL formation to the same level as CaO did by loading an appropriate MO content. Among all the tested catalysts, the BaO/m-ZrO2 calcined at 800?°C with a low BaO content (molar ratio of BaO/ZrO2?=?0.0452) shows the highest 2,3-BDO conversion (72.4%) and 3B2OL selectivity (74.4%) in the initial stage of 5?h at 350?°C. In order to characterize those catalysts, their catalytic activities, crystal structures, and basic properties were studied in detail. In X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) experiment, it was elucidated that highly dispersed M-O-Zr (M?=?Ca, Sr, and Ba) hetero-linkages were formed on the surface by loading these MOs onto m-ZrO2 with an appropriate content and then calcining at 800?°C. It can be concluded that the M-O-Zr hetero-linkages generate the proper base-acid balance for the efficient formation of 3B2OL from 2,3-BDO.
- Duan, Hailing,Yamada, Yasuhiro,Kubo, Shingo,Sato, Satoshi
-
-
- Rhodium-Complex-Catalyzed Hydroformylation of Olefins with CO2and Hydrosilane
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A rhodium-catalyzed one-pot hydroformylation of olefins with CO2, hydrosilane, and H2has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies indicate that the transformation is likely to proceed through a tandem sequence of poly(methylhydrosiloxane) (PMHS) mediated CO2reduction to CO and a conventional rhodium-catalyzed hydroformylation with CO/H2. The hydrosilylane-mediated reduction of CO2in preference to aldehydes was found to be crucial for the selective formation of aldehydes under the reaction conditions.
- Ren, Xinyi,Zheng, Zhiyao,Zhang, Lei,Wang, Zheng,Xia, Chungu,Ding, Kuiling
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supporting information
p. 310 - 313
(2016/12/30)
-
- Oxidative Esterification of Methacrolein to Methyl Methacrylate over Gold Nanoparticles on Hydroxyapatite
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The catalytic production of methyl methacrylate through the direct oxidative esterification of methacrolein is important in terms of green chemistry and sustainable development. In the present work, Au nanoparticles supported on three needle-like, lamella-like, and rodlike hydroxyapatites were synthesized. We demonstrated that needle-like hydroxyapatite could facilitate the higher dispersion of Au species because of its high specific surface area, and the strong interaction between the Au nanoparticles and the support resulted in the formation of more surface defects because of the existence of partially encapsulated Au particles by the needle-like hydroxyapatite. The surface defects were related closely to the generation of strong basic sites. Compared with the other two materials, the Au supported on the needle-like hydroxyapatite catalyst, which had a large amount of surface acid–base sites, exhibited a much higher catalytic activity and selectivity to methyl methacrylate in the direct oxidative esterification of methacrolein with methanol under mild reaction conditions (i.e., ambient pressure, low reaction temperature of 70 °C, and low methanol/aldehyde ratio of 8:1). The superior catalytic performance of the Au supported on needle-like hydroxyapatite catalyst was attributable to a cooperative effect between abundant acid–base sites for the preferential chemisorption of methacrolein and highly dispersed active Au species for the favorable formation of β-hydride and oxygen activation. The present findings open a new and promising route for the practical production of methyl methacrylate using high-performance hydroxyapatite-supported metal catalyst systems.
- Gao, Jun,Fan, Guoli,Yang, Lan,Cao, Xinzhong,Zhang, Peng,Li, Feng
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p. 1230 - 1241
(2017/04/14)
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- Unprotected Amino Acids as Stable Radical Precursors for Heterocycle C-H Functionalization
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An efficient and general method for the C-H alkylation of heteroarenes using unprotected amino acids as stable alkyl radical precursors is reported. This one-pot procedure is performed open to air under aqueous conditions and is effective for several natural and unnatural amino acids. Heterocycles of varying structure are suitably functionalized, and reactivity trends reflect the nucleophilic character of the radical species generated.
- Mai, Duy N.,Baxter, Ryan D.
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supporting information
p. 3738 - 3741
(2016/08/16)
-
- A modular family of phosphine-phosphoramidite ligands and their hydroformylation catalysts: steric tuning impacts upon the coordination geometry of trigonal bipyramidal complexes of type [Rh(H)(CO)2(P^P?)]
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Four new phosphine-phosphoramidite bidentate ligands have been synthesised and studied in rhodium-catalysed hydroformylation. Variable temperature NMR studies have been used along with HPIR to investigate the coordination mode of the trigonal bipyramidal complexes formed from [Rh(acac)(CO)2], ligand and syngas. It was found that small changes to the ligand structure have a large effect on the geometry of the active catalytic species. The rhodium catalysts of these new ligands were found to give unusually high iso-selectivity in the hydroformylation of propene and 1-octene.
- How, Rebecca C.,Hembre, Robert,Ponasik, James A.,Tolleson, Ginette S.,Clarke, Matthew L.
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p. 118 - 124
(2015/12/31)
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- Phosphorous compounds useful as ligands and compositions and methods regarding them
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This describes bidentate ferrocene-linked phosphine-phosphoramidate compounds. Hydroformylation catalyst compositions and methods of hydroformylation using the compounds are also disclosed. Methods of making the compounds are also disclosed.
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Page/Page column 16; 18; 19
(2016/05/09)
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- One-Step Production of 1,3-Butadiene from 2,3-Butanediol Dehydration
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We report the direct production of 1,3-butadiene from the dehydration of 2,3-butandiol by using alumina as catalyst. Under optimized kinetic reaction conditions, the production of methyl ethyl ketone and isobutyraldehyde, formed via the pinacol–pinacolone rearrangement, was markedly reduced and almost 80 % selectivity to 1,3-butadiene and 1,3-butadiene could be achieved. The presence of water plays a critical role in the inhibition of oligomerization. The amphoteric nature of γ-Al2O3was identified as important and this contributed to the improved catalytic selectivity when compared with other acidic catalysts.
- Liu, Xi,Fabos, Viktoria,Taylor, Stuart,Knight, David W.,Whiston, Keith,Hutchings, Graham J.
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p. 12290 - 12294
(2016/08/24)
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- ENZYMATIC METHODS FOR ISOBUTANOL PRODUCTION
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The present invention relates to a process of producing isobutanol, including: mixing water, lactate, an enzyme mixture including at least one enzyme, at least one cofactor, and at least one coenzyme, to prepare a reaction mixture; allowing catalytic conversions of lactate in the reaction mixture for a sufficient amount of time to produce isobutanol; and separating the isobutanol from a reactant obtained by the catalytic conversions, in which the conversion of lactate into isobutanol is in association with a NAD+/NADH and/or NADP+/NADPH regenerating system.
- -
-
Paragraph 00153-00157
(2016/07/05)
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- The Role of Structure and Conductivity of Perovskites Bi4V2-2x M2x O11-δ (M = Cu2+, Fe3+, Zr4+) in the Catalytic Dehydrogenation of Isobutanol
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The catalytic activity of solid electrolytes from the family of complex bismuth vanadates Bi4V2-2x M2xO11-δ (BIMEVOX) with V5+ ions partially substituted by 3d metal cations was studied. In the transformations of isobutanol, it was found to depend on the crystal structure (α, β, γ Aurivillius phases), which changes at increased dopant ion contents (xM). The highly conductive tetragonal γ phase was most active for all BIMEVOX oxides. The activation energy of the dehydrogenation of isobutanol EaC=O increased linearly with the charge of the M n+ ion and activation energy of conductivity of the γ phase of BIMEVOX in the series Cu2+ → Fe3+ → Zr4+.
- Mikhalenko,Povarova,Pylinina
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p. 771 - 776
(2016/04/20)
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- Conversion of 2,3-Butanediol over Phosphate Catalysts
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2,3-Butanediol (BDO) is an excellent feedstock for expanding the network of bio-based chemicals through catalytic technologies. The dehydration of BDO provides an alternative green route to important chemicals such as methyl ethyl ketone (MEK) and 1,3-butadiene (BD). In this contribution, we report on the catalytic performance of boron (BP), aluminum (AlP), titanium (TiP), zirconium (ZrP), and niobium (NbP) phosphates in BDO dehydration. The kinetic study points to three reaction pathways operating over phosphate catalysts, leading to MEK, 2-methyl-propanal (MP), and BD via intermediate 3-butene-2-ol (3B2OL) formation. The major reaction pathway is shown to involve pinacol rearrangement to MEK. The reactivity of phosphates is found to increase in the order: BPTiPZrP=NbPAlP. The best catalytic performance is achieved over AlP, which shows the highest selectivity towards MEK (78 %) at 100 % 2,3-butanediol conversion.
- Nikitina, Maria A.,Ivanova, Irina I.
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p. 1346 - 1353
(2016/04/20)
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- Influence of basicity on 1,3-butadiene formation from catalytic 2,3-butanediol dehydration over γ-alumina
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The direct catalytic conversion of 2,3-butanediol (BDO) to 1,3-butadiene (BD) was studied over two commercial forms of alumina (denoted as F200 and SCFa) at temperatures between 240?°C and 450?°C. Even though these two catalysts are both high surface area forms of γ-alumina, they gave remarkably different results, with SCFa giving higher BD selectivities at all experimental conditions. The difference is attributed to the higher surface area of F200, which means a greater number of acid sites that can convert BDO to methyl ethyl ketone (MEK). NH3 and CO2-TPD results supported this conclusion by showing that the two forms of alumina had different acid/base properties. Experimental results also showed that BD selectivity was improved by increasing temperature, increasing residence time and co-feeding water. The residence time study combined with density functional theory (DFT) calculations proved that 3-buten-2-ol (3B2OL) is an important intermediate in the conversion of BDO to BD. BD selectivity decreases over sodium modified alumina SCFa. It is hypothesized that on sodium-modified alumina, 3B2OL is dehydrogenated to form methyl vinyl ketone (MVK) as opposed to dehydration to BD. Basic sites catalyzed the retro-aldol condensation of MVK, which produces acetone and formaldehyde via cleavage of the C[dbnd]C bond. This is in agreement with DFT calculations showing that the proposed pathway for acetone formation is more energetically favored on Na-modified γ-Al2O3 (1?1?0) surface compared to the pristine (1?1?0) surface.
- Zeng, Fan,Tenn, William J.,Aki, Sudhir N.V.K.,Xu, Jiayi,Liu, Bin,Hohn, Keith L.
-
-
- PROCESS FOR PRODUCTION OF A BUTANAL
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Disclosed is a process for production of a butanal wherein said butanal is obtained by chemoselective C=C hydrogenation of a butenal in presence of a catalyst comprising palladium nanoparticles being immobilised in the cavities of a silica based mesocellular foam (MCF). The butanal yield in said process is >99% and the butenal selectivity is likewise >99%. The process is performed at a temperature of 15-30°C, at atmospheric pressure and at a reaction time of 10-30.
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Page/Page column 4
(2016/09/26)
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- Mild and Selective Catalytic Hydrogenation of the C=C Bond in α,β-Unsaturated Carbonyl Compounds Using Supported Palladium Nanoparticles
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Chemoselective reduction of the C=C bond in a variety of α,β-unsaturated carbonyl compounds using supported palladium nanoparticles is reported. Three different heterogeneous catalysts were compared using 1 atm of H2: 1) nano-Pd on a metal-organic framework (MOF: Pd0-MIL-101-NH2(Cr)), 2) nano-Pd on a siliceous mesocellular foam (MCF: Pd0-AmP-MCF), and 3) commercially available palladium on carbon (Pd/C). Initial studies showed that the Pd@MOF and Pd@MCF nanocatalysts were superior in activity and selectivity compared to commercial Pd/C. Both Pd0-MIL-101-NH2(Cr) and Pd0-AmP-MCF were capable of delivering the desired products in very short reaction times (10-90 min) with low loadings of Pd (0.5-1 mol %). Additionally, the two catalytic systems exhibited high recyclability and very low levels of metal leaching.
- Nagendiran, Anuja,Pascanu, Vlad,Bermejo Gómez, Antonio,González Miera, Greco,Tai, Cheuk-Wai,Verho, Oscar,Martín-Matute, Belén,B?ckvall, Jan-E.
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p. 7184 - 7189
(2016/05/19)
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