Xn:Harmful;
111-27-3Relevant articles and documents
Brown,H.C.,Kulkarni,S.U.
, p. 4169 - 4170 (1977)
Highly Efficient Photocatalytic Degradation of Dyes by a Copper–Triazolate Metal–Organic Framework
Liu, Chen-Xia,Zhang, Wen-Hua,Wang, Nan,Guo, Penghu,Muhler, Martin,Wang, Yuemin,Lin, Shiru,Chen, Zhongfang,Yang, Guang
, p. 16804 - 16813 (2018)
A copper(I) 3,5-diphenyltriazolate metal–organic framework (CuTz-1) was synthesized and extensively characterized by using a multi-technique approach. The combined results provided solid evidence that CuTz-1 features an unprecedented Cu5tz6 cluster as the secondary building unit (SBU) with channels approximately 8.3 ? in diameter. This metal–organic framework (MOF) material, which is both thermally and chemically (basic and acidic) stable, exhibited semiconductivity and high photocatalytic activity towards the degradation of dyes in the presence of H2O2. Its catalytic performance was superior to that of reported MOFs and comparable to some composites, which has been attributed to its high efficiency in generating .OH, the most active species for the degradation of dyes. It is suggested that the photogenerated holes are trapped by CuI, which yields CuII, the latter of which behaves as a catalyst for a Fenton-like reaction to produce an excess amount of .OH in addition to that formed through the scavenging of photogenerated electrons by H2O2. Furthermore, it was shown that a dye mixture (methyl orange, methyl blue, methylene blue, and rhodamine B) could be totally decolorized by using CuTz-1 as a photocatalyst in the presence of H2O2 under the irradiation of a Xe lamp or natural sunlight.
New selectivities from old catalysts. Occlusion of Grubbs' catalysts in PDMS to change their reactions
Brett Runge,Mwangi, Martin T.,Bowden, Ned B.
, p. 5278 - 5288 (2006)
This article describes new selectivities for Grubbs' first and second generation catalysts when occluded in a hydrophobic matrix of polydimethylsiloxane (PDMS). Occlusion of catalysts in mm-sized slabs of PDMS is accomplished by swelling with methylene chloride then removing the solvent under vacuum. The catalysts are homogenously dissolved in PDMS yet remain catalytically active. Many substrates that react by olefin metathesis with Grubbs' catalysts freely dissolved in methylene chloride also react by olefin isomerization with occluded catalysts. Eleven examples of substrates that exhibit dual reactivity by undergoing olefin isomerization with occluded catalysts and olefin metathesis with catalysts dissolved in methylene chloride are reported. Most of these substrates have olefins with allylic phosphine oxides, carbonyls, or ethers. Control experiments demonstrate that isomerization is occurring in the solvent by decomposition of the catalyst from a ruthenium carbene to a proposed ruthenium hydride. This work was extended by heating occluded Grubbs' first generation catalyst to 100 °C in 90% MeOH in H2O in the presence of various alkenes to transform the Grubbs' catalyst into an isomerization catalyst for unfunctionalized olefins. This work demonstrates that occlusion of organometallic catalysts in PDMS has important implications for their reactions and can be used as a method to control which reactions they catalyze.
Mechanistic study of the selective hydrogenation of carboxylic acid derivatives over supported rhenium catalysts
Toyao, Takashi,Ting, Kah Wei,Siddiki, S. M. A. Hakim,Touchy, Abeda S.,Onodera, Wataru,Maeno, Zen,Ariga-Miwa, Hiroko,Kanda, Yasuharu,Asakura, Kiyotaka,Shimizu, Ken-ichi
, p. 5413 - 5424 (2019)
The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are not accompanied by reduction of aromatic moieties. A Re loading amount of 5 wt% and a catalyst pretreatment with H2 at 500 °C were identified as being optimal to obtain the highest catalytic activity for the hydrogenation processes. The results of studies using various characterization methods, including X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM), indicate that the Re species responsible for the catalytic hydrogenation processes have sub-nanometer to a few nanometer sizes and average oxidation states higher than 0 and below +4. The presence of either a carboxylic acid and/or its corresponding alcohol is critical for preventing the Re/TiO2 catalyst from promoting production of dearomatized byproducts. Although Re/TiO2 is intrinsically capable of hydrogenating aromatic rings, carboxylic acids, alcohols, amides, and amines strongly adsorb on the Re species, which leads to suppression of this process. Moreover, the developed catalytic system was applied to selective hydrogenation of triglycerides that form the corresponding alcohols.
LiBH4-promoted Hydroboration of Alkenes with 1,3,2-Benzodioxaborole
Arase, Akira,Nunokawa, Yutaka,Masuda, Yuzuru,Hoshi, Masayuki
, p. 205 - 206 (1991)
In the presence of a small amount of LiBH4 mono-, di-, tri- and tetr-substituted ethenes were hydroborated almost quantitatively with 1,3,2-benzodioxaborole (catecholborane) under very mild conditions.
Catalytic conversion of ethanol into an advanced biofuel: Unprecedented selectivity for n-butanol
Dowson, George R. M.,Haddow, Mairi F.,Lee, Jason,Wingad, Richard L.,Wass, Duncan F.
, p. 9005 - 9008 (2013)
Taming the beast: Unprecedented selectivity of over 94 % at good (20 %+) conversion was observed for the upgrade of ethanol to the advanced biofuel 1-butanol with a ruthenium diphosphine catalyst (see picture; P orange, Ru blue). Preliminary mechanistic studies indicate that control over the notoriously uncontrolled acetaldehyde aldol condensation is critical for the high selectivity, and evidence was found for an on-metal condensation step. Copyright
Revised Mechanisms of the Catalytic Alcohol Dehydrogenation and Ester Reduction with the Milstein PNN Complex of Ruthenium
Gusev, Dmitry G.
, (2020)
The combined experimental/DFT computational study of RuH2(CO)[Et2NCH2PyCH2Pt-Bu2] (2) suggests that this dihydride is the catalyst of the acceptorless alcohol dehydrogenation and ester hydrogenation reactions developed in the group of Milstein, whereas the corresponding alkoxide RuH(OR)(CO)[Et2NCH2PyCH2Pt-Bu2] (4) is an important reaction intermediate. A relatively fast equilibrium of dihydride 2 and ethanol with ethoxide 4 and H2 was demonstrated by NMR experiments, as well as the proton exchanges occurring between the OH of ethanol, RuH, and the CH2 groups of the PNN ligand backbone of 2 and 4. A detailed critical discussion of the previously proposed mechanisms with the Milstein catalyst is presented. This paper also reports the preparation of the osmium dihydride OsH2(CO)[Et2NCH2PyCH2Pt-Bu2] (2-Os) and a comparative study of 2, 2-Os, and the Noyori-type osmium catalyst OsH2(CO)[PyCH2NHCH2CH2NHPt-Bu2].
A new route of the reaction of EtAlCl2 with α-olefins catalyzed by Ti complexes
Ibragimov,Khafizova,Zagrebel'naya,Parfenova,Sultanov,Khalilov,Dzkemilev
, p. 292 - 296 (2001)
A new method for the synthesis of dialkyl(ethyl)alanes by the reaction of EtAlCl2 with α-olefins in the presence of Mg and a catalytic amount of Cp2TiCl2 (Ti(OPri)4, Ti(OBun)4) in THF was developed.
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Hurd,McNamee
, (1937)
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Enzymes inhibitory constituents from Buddleja crispa
Ahmad, Ijaz,Malik, Abdul,Afza, Nighat,Anis, Itrat,Fatima, Itrat,Nawaz, Sarfraz Ahmad,Tareen, Rasool Bukhsh,Iqbal Choudhary
, p. 341 - 346 (2005)
Steroidal galactoside 1 and aryl esters 2 and 3 have been isolated from Buddleja crispa, along with ginipin 4, gardiol 5, 1-heptacosanol 6, and methyl benzoate 7, isolated for the first time from this species. The structures of all of the compounds were determined by spectroscopic techniques and chemical studies. The steroidal galactoside 1 is an inhibitor of lipoxygenase. Compounds 1-3 displayed inhibitory activity against butyrylcholinesterse, while compounds 2 and 3 further showed inhibition against acetylcholinesterase.
Harris et al.
, p. C27 (1974)
In-Situ generation of surface-active HCo(CO)y like intermediate from gold supported on ion-promoted Co3O4 for induced hydroformylation-hydrogenation of alkenes to alcohols
Akinnawo, Christianah A.,Meijboom, Reinout,Mogudi, Batsile M.,Oseghale, Charles O.
, (2020)
In this study, a greener and stable surface-active cobalt-carbonyl like specie [HCo(CO)y] was generated via H2 and CO spillover by gold on ion-promoted cobalt oxide. The supports and catalysts syntheses were based on inverse micelle and deposition-precipitation methods, respectively. The temperature-programmed reduction was used for optimization to obtain the best supports. The catalysts with activity (Co3O4 3O4 3O4 and Au loadings 10 percent 3O4 catalyst more active than the others and displayed excellent alcohol chemoselectivity with varying regioselectivity under milder reaction conditions. The reaction was assumed to take place via the formation of [HCo(CO)y] specie, as the active catalytic site of the catalyst. The enhanced catalytic performance was also ascribed to the low-temperature reducibility and surface basicity of the nanomaterials. The stability of the catalyst was evaluated by recycling, with its mesostructure retained after four cycles.
Lithium Triethylborohydride-promoted Hydroboration of Alkenes with Dialkoxyboranes
Arase, Akira,Nunokawa, Yutaka,Masuda, Yuzuru,Hoshi, Masayuki
, p. 51 - 52 (1992)
In the presence of a catalytic ammount of lithium triethylborohydride (LiBEt3H) the hydroboration of alkenes with dialkoxyboranes is promoted markedly to provide the hydroboration products almost quantitatively under mild reaction conditions.
Hydroboration. 54. New General Synthesis of Alkyldihaloboranes via Hydroboration of Alkenes with Dihaloborane-Dimethyl Sulfide Complexes. Unusual Trends in the Reactivities and Directive Effects
Brown, Herbert C.,Ravindran, N.,Kulkarni, Surendra U.
, p. 384 - 389 (1980)
The reactions of alkenes with the dimethyl sulfide complexes of the dihaloboranes (HBX2*SMe2; X = Cl, Br, I) have been studied in detail.Dichloroborane-dimethyl sulfide (HBCl2*SMe2) hydroborates representative olefins relatively slowly and requires the presence of a strong Lewis acid, such as boron trichloride, to complete the hydroboration reaction rapidly.Unexpectedly, dibromoborane-dimethyl sulfide (HBBr2*SMe2) and diiodoborane-dimethyl sulfide (HBI2*SMe2) react readily with olefins, even in the absence of such Lewis acids.This is contrary to the trend expected on the basis of the strenghts of these methyl sulfide adducts and a hydroboration mechanism involving a prior dissociation of the addition compound.The hydroboration of olefins with these reagents, followed by distillation under reduced pressure, affords alkyldihaloborane-dimethyl sulfide complexes in good yields.These are readily converted by hydrolysis into the boronic acids or by methanolysis to the corresponding esters.Oxidation with alkaline hydrogen peroxide utilizing sufficient sodium hydroxide to neutralize the hydrogen halide readily provides the corresponding alcohols.HBBr2*SMe2 and HBI2*SMe2 exhibit an unusual directive effect in the hydroboration of trisubstituted olefins, giving unexpected enhanced amounts of the Markovnikov (tertiary) derivatives.
Alkene-pinacolborane hydroborations catalyzed by lanthanum tris[bis(trimethylsilyl)amide]
Horino, Yoshikazu,Livinghouse, Tom,Stan, Magdalena
, p. 2639 - 2641 (2004)
Tris[bis(trimethylsilyl)amide] has been shown to be an effective catalyst for the hydroboration of representative alkenes and styrenes by pinacolborane.
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Bigley,Payling
, p. 3974 (1965)
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Upgrading ethanol to 1-butanol with a homogeneous air-stable ruthenium catalyst
Tseng, Kuei-Nin T.,Lin, Steve,Kampf, Jeff W.,Szymczak, Nathaniel K.
, p. 2901 - 2904 (2016)
An amide-derived N,N,N-Ru(ii) complex catalyzes the conversion of EtOH to 1-BuOH with high activity. Conversion to alcohol upgraded products exceeds 250 turnovers per hour (>50% conversion) with 0.1 mol% catalyst loading. In addition to high activity for ethanol upgrading, catalytic reactions can be set up under ambient conditions with no loss in activity.
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Cottle,Hollyday
, p. 510,513,514 (1947)
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The key role of the latent N-H group in Milstein's catalyst for ester hydrogenation
Chianese, Anthony R.,He, Tianyi,Jarczyk, Cole E.,Keith, Jason M.,Kelly, Sophie. E.,Kim, Thao,Pham, John,Reynolds, Eamon F.
, p. 8477 - 8492 (2021)
We previously demonstrated that Milstein's seminal diethylamino-substituted PNN-pincer-ruthenium catalyst for ester hydrogenation is activated by dehydroalkylation of the pincer ligand, releasing ethane and eventually forming an NHEt-substituted derivative that we proposed is the active catalyst. In this paper, we present a computational and experimental mechanistic study supporting this hypothesis. Our DFT analysis shows that the minimum-energy pathways for hydrogen activation, ester hydrogenolysis, and aldehyde hydrogenation rely on the key involvement of the nascent N-H group. We have isolated and crystallographically characterized two catalytic intermediates, a ruthenium dihydride and a ruthenium hydridoalkoxide, the latter of which is the catalyst resting state. A detailed kinetic study shows that catalytic ester hydrogenation is first-order in ruthenium and hydrogen, shows saturation behavior in ester, and is inhibited by the product alcohol. A global fit of the kinetic data to a simplified model incorporating the hydridoalkoxide and dihydride intermediates and three kinetically relevant transition states showed excellent agreement with the results from DFT.
HYDROMAGNESATION OF UNSATURATED COMPOUNDS USING DIETHYLAMINOMAGNESIUM HYDRIDE, CATALYZED BY TRANSITION METAL COMPLEXES
Vostrikova, O. S.,Sultanov, R. M.,Dzhemilev, U. M.
, p. 1724 - 1726 (1983)
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Chemoselective hydrogenolysis of tetrahydrofurfuryl alcohol to 1,5-pentanediol
Koso, Shuichi,Furikado, Ippei,Shimao, Akira,Miyazawa, Tomohisa,Kunimori, Kimio,Tomishige, Keiichi
, p. 2035 - 2037 (2009)
Direct conversion of tetrahydrofurfuryl alcohol, which is one of the biomass-derived chemicals, to 1,5-pentanediol was realized by chemoselective hydrogenolysis catalyzed by Rh/SiO2 modified with ReOx species, and this reaction route gave higher yield than the conventional multi-step method.
N-methylpyrrolidine-zinc borohydride: As a new stable and efficient reducing agent in organic synthesis
Tajbakhsh,Lakouraj,Mohanazadeh,Ahmadi-Nejhad
, p. 229 - 236 (2003)
N-Methylpyrrolidine-zinc borohydride is readily prepared and used for reduction of a variety of organic compounds such as aldehydes, ketones, acid chlorides, and esters. Reactions are performed in THF at room temperature or under reflux condition and the yields are good to excellent. Complete regio-selectivity are observed in reduction of α,β-unsaturated carbonyl compounds.
Selective hydrogenation of 3-Hexyn-1-ol with Pd nanoparticles synthesized via microemulsions
Montsch, Thomas,Heuchel, Moritz,Traa, Yvonne,Klemm, Elias,Stubenrauch, Cosima
, p. 19 - 28 (2017)
In the study at hand we present a design strategy for novel catalysts which can be used for the selective hydrogenation of alkynes to alkenes. The design of the novel catalysts is based on two main ideas, namely (1) the synthesis of Pd nanoparticles via microemulsions and (2) the use of highly-ordered mesoporous silica with a 3-D pore network (FDU-12) serving as support. The nanoparticles are deposited on FDU-12 in two different ways. Firstly, we simply impregnated the support with a dispersion of the nanoparticles. The resulting catalyst was not selective at all; on the contrary, it fully hydrogenated our model alkyne, namely 3-hexyn-1-ol. Secondly, we synthesized the FDU-12 in the presence of the nanoparticles (in-situ synthesis). In this case, we obtained one catalyst which performed as well as the Lindlar catalyst although the metal content was slightly lower and our catalyst contained no Pb. Another catalyst of the same series, prepared in the presence of another stabilizer, performed as well as the NanoSelect catalyst but at a 7 times higher metal content. For the sake of comparison we also impregnated FDU-12 via classical incipient wetness impregnation and again obtained a completely nonselective catalyst. Our results demonstrate that the in-situ synthesis has great potential as regards the development of novel catalysts.
Hach
, p. 340 (1974)
Hydrogenation of adipic acid to 1,6-hexanediol by supported bimetallic Ir-Re catalyst
Li, Xiaoyue,Liang, Changhai,Luo, Jingjie
, (2020)
A series of supported Ir-Re catalysts have been synthesized and used for the hydrogenation of adipic acid to 1,6-hexanediol. The influences of supporting materials and the Ir/Re atomic ratio on the catalytic performances have been studied. Results suggested that Ir-Re supported on carbon materials and alumina had appropriate acid sites and better activity for the hydrogenation of adipic acid. Compared to the monometallic catalysts, synergistic interaction was generated and electrons were delivered from Ir to Re. The uniform distribution of metal particles in the Ir-Re catalysts and the well restrained H2-spillover effect facilitated the transformation of adipic acid and the selective production of 1,6-hexanediol. The selectivity of 1,6-hexanediol was 59% with complete conversion of adipic acid at 180 °C in 10 MPa H2 after reaction for 16 h. After four times of reaction, the selectivity of 1,6-hexanediol only decreased about 4%.
Regiodivergent Reductive Opening of Epoxides by Catalytic Hydrogenation Promoted by a (Cyclopentadienone)iron Complex
De Vries, Johannes G.,Gandini, Tommaso,Gennari, Cesare,Jiao, Haijun,Pignataro, Luca,Stadler, Bernhard M.,Tadiello, Laura,Tin, Sergey
, p. 235 - 246 (2022/01/03)
The reductive opening of epoxides represents an attractive method for the synthesis of alcohols, but its potential application is limited by the use of stoichiometric amounts of metal hydride reducing agents (e.g., LiAlH4). For this reason, the corresponding homogeneous catalytic version with H2 is receiving increasing attention. However, investigation of this alternative has just begun, and several issues are still present, such as the use of noble metals/expensive ligands, high catalytic loading, and poor regioselectivity. Herein, we describe the use of a cheap and easy-To-handle (cyclopentadienone)iron complex (1a), previously developed by some of us, as a precatalyst for the reductive opening of epoxides with H2. While aryl epoxides smoothly reacted to afford linear alcohols, aliphatic epoxides turned out to be particularly challenging, requiring the presence of a Lewis acid cocatalyst. Remarkably, we found that it is possible to steer the regioselectivity with a careful choice of Lewis acid. A series of deuterium labeling and computational studies were run to investigate the reaction mechanism, which seems to involve more than a single pathway.
Chemoenzymatic one-pot reaction from carboxylic acid to nitrile: Via oxime
Hecko, Sebastian,Horvat, Melissa,Klempier, Norbert,Martínková, Ludmila,Pátek, Miroslav,R?disch, Robert,Rudroff, Florian,Schiefer, Astrid,Weilch, Victoria,Wilding, Birgit,Winkler, Margit
, p. 62 - 66 (2022/01/22)
We report a new chemoenzymatic cascade starting with aldehyde synthesis by carboxylic acid reductase (CAR) followed by chemical in situ oxime formation. The final step to the nitrile is catalyzed by aldoxime dehydratase (Oxd). Full conversions of phenylacetic acid and hexanoic acid were achieved in a two-phase mode.
Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups
Amberchan, Gabriella,Snelling, Rachel A.,Moya, Enrique,Landi, Madison,Lutz, Kyle,Gatihi, Roxanne,Singaram, Bakthan
supporting information, p. 6207 - 6227 (2021/05/06)
The binary hydride, diisobutylaluminum borohydride [(iBu)2AlBH4], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)2AlBH4, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)2AlBH4 has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)2AlBH4, DIBAL, and BMS are discussed.
