Xn:Harmful;
6032-29-7Relevant articles and documents
METHOD FOR PRODUCING ALCOHOL
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Paragraph 0103-0111; 0124-0127; 0133-0137, (2022/02/05)
The present invention provides a method for selectively producing an alcohol by efficiently hydrogenating a lactone. The present invention is a method for producing an alcohol, the method including hydrogenating a substrate lactone represented by Formula (1), in the presence of a catalyst described below, to produce an alcohol that is represented by Formula (2). In the formulae, R represents a divalent hydrocarbon group which may have a hydroxyl group. The catalyst comprises: metal species including M1 and M2; and a support supporting the metal species, and wherein M1 is rhodium, platinum, ruthenium, iridium, or palladium; M2 is tin, vanadium, molybdenum, tungsten, or rhenium; and the support is hydroxyapatite, fluorapatite, hydrotalcite, or ZrO2.
Chromium-Catalyzed Production of Diols From Olefins
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Paragraph 0111, (2021/03/19)
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.
Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
, p. 2108 - 2114 (2021/02/06)
Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
Synthesis and structural elucidation of (pyridyl)imine Fe(II) complexes and their applications as catalysts in transfer hydrogenation of ketones
Tsaulwayo, Nokwanda,Kumah, Robert T.,Ojwach, Stephen O.
, (2021/01/25)
Reactions of (pyridyl)imine ligands: 2,6-diisopropyl-N-[(pyridine-2-yl)methylene]aniline (L1), 2,6-diisopropyl-N-[(pyridine-2-yl)ethylidene]aniline (L2), 2,6-dimethyl-N-[(pyridine-2-yl)methylene]aniline (L3), 2,6-dimethyl-N-[(pyridine-2-yl)ethylidene]aniline (L4) and N-[(pyridine-2-yl)methylene]aniline (L5) with FeCl2 salt afforded the corresponding paramagnetic Fe(II) complexes [Fe(L1)2Cl][FeCl4] (Fe1), [Fe(L2)2Cl][FeCl4] (Fe2), [Fe(L3)2Cl][FeCl4] (Fe3), [Fe(L4)2Cl][FeCl4], (Fe4), [Fe(L5)2Cl2] (Fe5) in good yields. On the other hand, reactions of L1 with FeCl2 in the presence of NaPF6 afforded complex [Fe(L1)2Cl][PF6] (Fe6) in moderate yields. Molecular structures of complexes Fe1 and Fe2 reveal the formation of cationic species containing two N^N bidentate ligands and one chlorido co-ligand to give five-coordinate geometry with [FeCl4]? as counter-anion. On the other hand, complex Fe5, is an octahedral neutral species containing two bidentate L5 and two chlorido ligands. All the complexes (Fe1–Fe6) formed active catalysts in the transfer hydrogenation of ketones affording average yields of about 85%. The ligand architecture, reaction conditions and nature of substrate influenced the catalytic activities of the complexes. Mercury and subs-stoichiometric poisoning tests pointed to the existence of both Fe(0) nanoparticles and homogeneous Fe(II) species as the active intermediates.
Ni2P Nanoalloy as an Air-Stable and Versatile Hydrogenation Catalyst in Water: P-Alloying Strategy for Designing Smart Catalysts
Fujita, Shu,Yamaguchi, Sho,Yamasaki, Jun,Nakajima, Kiyotaka,Yamazoe, Seiji,Mizugaki, Tomoo,Mitsudome, Takato
supporting information, p. 4439 - 4446 (2021/02/09)
Non-noble metal-based hydrogenation catalysts have limited practical applications because they exhibit low activity, require harsh reaction conditions, and are unstable in air. To overcome these limitations, herein we propose the alloying of non-noble metal nanoparticles with phosphorus as a promising strategy for developing smart catalysts that exhibit both excellent activity and air stability. We synthesized a novel nickel phosphide nanoalloy (nano-Ni2P) with coordinatively unsaturated Ni active sites. Unlike conventional air-unstable non-noble metal catalysts, nano-Ni2P retained its metallic nature in air, and exhibited a high activity for the hydrogenation of various substrates with polar functional groups, such as aldehydes, ketones, nitriles, and nitroarenes to the desired products in excellent yields in water. Furthermore, the used nano-Ni2P catalyst was easy to handle in air and could be reused without pretreatment, providing a simple and clean catalyst system for general hydrogenation reactions.
Highly efficient catalytic transfer hydrogenation of furfural over defect-rich amphoteric ZrO2with abundant surface acid-base sites
Zhu, Zekun,Yang, Lingling,Ke, Changxuan,Fan, Guoli,Yang, Lan,Li, Feng
, p. 2616 - 2626 (2021/03/03)
Currently, the catalytic transformation and utilization of biomass-derived compounds are of great importance to the alleviation of environmental problems and sustainable development. Among them, furfural alcohol derived from biomass resources has been found to be one of the most prospective biomass platforms for high-value chemicals and biofuels. Herein, high-surface-area ZrO2 with abundant oxygen defects and surface acid-base sites was synthesized and used as a heterogeneous catalyst for the catalytic transfer hydrogenation of furfural into furfural alcohol using alcohol as a hydrogen donor. The as-synthesized ZrO2 exhibited excellent catalytic performance with 98.2% FA conversion and 97.1% FOL selectivity, even comparable with that of a homogeneous Lewis acid catalyst. A series of characterization studies and experimental results revealed that acid sites on the surface of ZrO2 could adsorb and activate the CO bond in furfural and base sites could facilitate the formation of alkoxide species. The synergistic effect of surface acid-base sites affords a harmonious environment for the reaction, which is crucial for catalytic transfer hydrogenation of furfural with high efficiency. Furthermore, the as-prepared ZrO2 catalyst also exhibited a potential application for the efficient catalytic transfer hydrogenation of a series of biomass-derived carbonyl compounds. This journal is
Asymmetric reduction of 2-chloro-3-oxo-ester into enantiomerically high pure diltiazem precursor by a Candida ketoreductase
Chen, Cheng,Chen, Qi,Ni, Guo-Wei,Pan, Jiang,Xu, Jian-He,Xuan, Yang
, (2021/07/02)
Methyl (2R,3S)-3-(4-methoxyphenyl)glycidate [(2R,3S)-MPGM] is an advanced chiral synthon for the synthesis of the cardiovascular drug diltiazem. It can be easily accessed by cyclizing the reduction products of methyl 2-chloro-3-(4-methoxyphenyl)-3-oxo-propanoate (1a). Herein, we report an identified carbonyl reductase (CpKR) from Candida parapsilosis that displayed an excellent stereoselectivity toward the keto substituent at the C3-position of the 2-chloro-3-oxo-ester 1a. The engineered Escherichia coli cells harboring CpKR gene were directly applied for the asymmetric reduction of keto ester 1a with a space-time yield of 46 g L?1 d?1, which represents the highest productivity in bio-reduction of 1a reported so far. The isolated chiral alcohol products were then applied to the chemical synthesis of (2R,3S)-MPGM in 99% ee and a total yield of 76% in the two-step chemo-enzymatic reactions, which far exceeded the maximum theoretical yield (50%) of the existing industrial process based on a lipase-catalyzed resolution of racemic MPGM. This work provides a promising eco-friendly and cost-effective route toward industrial synthesis of pharmaceutically relevant diltiazem.
Catalytic transfer hydrogenation of ethyl levulinate to γ-valerolactone over supported MoS2catalysts
Diao, Xinyong,Ji, Na,Jiang, Sinan,Liu, Caixia,Liu, Qingling,Liu, Zhenyu,Lu, Xuebin,Ma, Degang,Song, Chunfeng,Yu, Zhihao
, p. 5062 - 5076 (2021/08/16)
The hydrogenation of levulinate esters to γ-valerolactone (GVL) is an important step in the transformation of biomass into biofuels. It is attractive to develop new efficient systems for the catalytic transfer hydrogenation (CTH) of levulinate esters to value-added GVL. In this work, a series of MoS2-based supported catalysts were prepared via an impregnation method for the CTH of biomass-derived ethyl levulinate (EL) to GVL. By comprehensive characterization and catalytic measurements, we found that the CTH activity of EL to GVL is closely related to the MoS2 morphology and acid distribution on the support. Among the catalysts with different supports, the AC support with abundant Lewis acid sites and large surface area facilitated the high dispersion of low stacked MoS2 slabs, and the MoS2-acid synergistic catalysis contributed to the superior activity and selectivity. The conversion of EL and the selectivity of GVL reached 97.2% and 91.2% under optimized conditions over the MoS2/AC catalyst (230 °C, 1 MPa H2, 1.5 h), respectively. We also conducted reaction kinetic experiments to reveal the relationship between the active site of the MoS2/AC catalyst and its catalytic performance, and the plausible reaction pathway and mechanism over MoS2/AC was proposed. The catalytic performance gradually declined during recycling tests due to the oxidation of MoS2 and can be easily recovered by resulfuration.
NHC ligand-based half-sandwich iridium complexes: synthesis, structure and catalytic activity in acceptorless dehydrogenation and transfer hydrogenation
Deng, Wei,Jin, Yan,Li, Rong-Jian,Liu, Zhen-Jiang,Wang, Yang,Yao, Zi-Jian
, p. 19002 - 19010 (2021/10/29)
A set of neutral C,C-chelate half-sandwich iridium(iii) complexes have been prepared with NHC ligands that contain pendant aromatic rings as potentially chelating donor sites. The catalytic activity of such iridium complexes has been investigated for the acceptorless dehydrogenation (AD) reactions of alcohols and for the transfer hydrogenation reactions of ketones. The prepared iridium(iii) complexes show excellent catalytic activity for AD reactions of a wide range of secondary alcohols, and they are also shown to be effective for the synthesis of aldehydes from primary alcohols without the observation of undesired byproducts such as esters. Additionally, these complexes are also highly efficient in transfer hydrogenation of ketones and aldehydes, which give the alcohols in good yields under mild conditions. The exact structure and bonding mode of the NHC-based iridium complexes was identified using various spectroscopic methods and single crystal X-ray analysis.
Furfural hydrodeoxygenation (HDO) over silica-supported metal phosphides – The influence of metal–phosphorus stoichiometry on catalytic properties
Lan, Xuefang,Pestman, Robert,Hensen, Emiel J.M.,Weber, Thomas
, p. 181 - 193 (2021/02/27)
The gas-phase hydrodeoxygenation (HDO) of furfural, a model compound for bio-based conversion, was investigated over transition metal phosphide catalysts. The HDO activity decreases in the order Ni2P ≈ MoP > Co2P ≈ WP ? Cu3P > Fe2P. Nickel phosphide phases (e.g., Ni2P, Ni12P5, Ni3P) are the most promising catalysts in the furfural HDO. Their selectivity to the gasoline additives 2-methylfuran and tetrahydro-2-methylfuran can be adjusted by varying the P/Ni ratio. The effect of P on catalyst properties as well as on the reaction mechanism of furfural HDO were investigated in depth for the first time. An increase of the P stoichiometry weakens the furan-ring/catalyst interaction, which contributes to a lower ring-opening and ring-hydrogenation activity. On the other hand, an increasing P content does lead to a stronger carbonyl/catalyst interaction, i.e., to a stronger η2(C, O) adsorption configuration, which weakens the C1[sbnd]O1 bond (Scheme 1) in the carbonyl group and enhances the carbonyl conversion. Phosphorus species can also act as Br?nsted acid sites promoting C1[sbnd]O1 (Scheme 1) hydrogenolysis of furfuryl alcohol, hence contributing to higher production of 2-methylfuran.
