122-97-4Relevant articles and documents
Molybdenum oxide-mediated facile aliphatic nucleophilic fluorination
Said, Madhukar S.,Khandare, Lina,Shinde, Sandip S.
, p. 59 - 62 (2017)
A facile aliphatic nucleophilic fluorination with cesium fluoride in the presence of molybdenum oxide as a catalyst has been demonstrated. Reactivity of molybdenum oxide in nanocrystal form was found to be chemoselective in the presence of water. Furthermore, the reaction is highly specific with alkyl sulfonate substrates.
-
Searles
, p. 124 (1951)
-
Enhanced Pd-catalyzed hydrogenation of olefins within polymeric microreactors under organic/aqueous biphasic conditions
Lan, Yang,Zhang, Minchao,Zhang, Wangqing,Yang, Li
, p. 3670 - 3673 (2009)
A microreactor of a water-soluble hollow polymeric microsphere with Pd nanoparticles immobilized in the wall was proposed for the hydrogenation of olefins under organic and aqueous biphasic conditions. It was found that the microreactor was stable and was used in practical application for continuous hydrogenation of olefins on a technical scale without deactivation in activity. It was composed of three parts, such as the outer corona of polyacrylamide (PAM), the cross-linked and hydrophobic wall of poly[styrene-co-2-(acetoacetoxy) -ethylmethacrylate] (PS-co-PAEMA), and 3.9 mm Pd nanoparticles. Hollow microspheres were constructed using several procedures of seed polymerization along with removal of the seed for the synthesis of the microreactor. It was observed that the microreactor dispersed easily in aqueous phase due to the presence of the hydrophilic PAM corona. The hydrogenation of CA with H 2 was also evaluated to investigate hydrogenation of olefins within the microreactor.
Regiospecific reduction of oxetanes with lithium under aprotic conditions
Rama,Pasha
, p. 1073 - 1074 (2000)
Substituted oxetanes have been found to give exclusively terminal alcohols by regiospecific ring-opening with lithium and biphenyl (cat.) in THF at reflux. (C) 2000 Elsevier Science Ltd.
Amphiphilic ionic liquid stabilizing palladium nanoparticles for highly efficient catalytic hydrogenation
Zhu, Wenwen,Yang, Hanming,Yu, Yinyin,Hua, Li,Li, Huan,Feng, Bo,Hou, Zhenshan
, p. 13492 - 13500 (2011)
The highly water-soluble palladium nanoparticles (NPs) were synthesized by using the amphiphilic poly(ethylene glycol)-functionalized dicationic imidazolium-based ionic liquid (C12Im-PEG IL) as a stabilizing agent. The aqueous dispersed palladium NPs in the range of 1.9 ± 0.3 nm were observed by transmission electron microscopy (TEM). The physicochemical properties of C12Im-PEG IL in aqueous phase have been characterized by electrical conductivity, surface tension and dynamic light scattering (DLS) measurements. It was demonstrated that the amphiphilic ionic liquid can form micelles above its critical micelle concentration (CMC) in aqueous solution and the micelles played a crucial role in stabilizing the palladium NPs and thus promoted catalytic hydrogenation. Furthermore, the dicationic ionic liquid can also act as a gemini surfactant and generated emulsion between hydrophobic substrates and the catalytic aqueous phase during the reaction. The aqueous dispersed palladium NPs showed efficient activity for the catalytic hydrogenation of various substrates under very mild conditions and the stabilizing Pd(0) nanoparticles (NPs) can be reused at least eight times with complete conservation of activity. the Owner Societies 2011.
Scrap waste automotive converters as efficient catalysts for the continuous-flow hydrogenations of biomass derived chemicals
Cova, Camilla Maria,Zuliani, Alessio,Manno, Roberta,Sebastian, Victor,Luque, Rafael
, p. 1414 - 1423 (2020)
The catalytic activity of scrap ceramic-cores of automotive catalytic converters (SCATs) was investigated in the continuous-flow hydrogenation of different biomass-derived chemicals. The waste SCAT powders were deeply characterized by ICP-MS, TGA, MP-AES, XRD, N2 physisorption, TPR, HRTEM and EDS before and after utilization as a catalyst. The hydrogenation reactions of isopulegol to menthol, cinnamyl alcohol to hydrocinnamyl alcohol, isoeugenol to dihydroeugenol, vanillin to vanillyl alcohol and benzaldehyde to benzyl alcohol were performed studying the influence of various reaction parameters (temperature, pressure, flow rate and concentration of the starting material) on the final yields. The outstanding performance and stability obtained for the low metal content of waste-derived catalysts can be attributed to the co-presence of different noble metals as well as to the composite structure itself.
Solvent-mediated chemoselective reduction of aldehydes by using tributyltin hydride in methanol, aqueous organic solvents, or water: An environmentally benign process
Kamiura, Koji,Wada, Makoto
, p. 9059 - 9062 (1999)
Aldehydes are reduced chemoselectively by using tributyltin hydride in methanol, aqueous organic solvents, or water to provide the corresponding alcohols in high yields. No additional catalyst is required.
Enhancing the performance of SBA-15-supported copper catalysts by chromium addition for the chemoselective hydrogenation of trans-cinnamaldehyde
Dragoi,Ungureanu,Chirieac,Hulea,Royer,Dumitriu
, p. 2319 - 2329 (2013)
SBA-15-supported copper-chromium mixed oxide nanoparticles (CuCr/SBA-15) were prepared by incipient wetness impregnation followed by mild drying at 25°C and calcination. The Cu:Cr weight ratios were 1:1, 5:1, and 10:1, at a constant total loading of 5 wt%. Monocomponent SBA-15-supported Cu-oxide (Cu/SBA-15) and Cr-oxide (Cr/SBA-15) were prepared as reference samples. The materials were systematically characterized by XRD at low and high angles, N2 physisorption, DR UV-vis, FT-IR, and XPS spectroscopies, and TPR. XRD at low angles and N2 physisorption confirmed the preservation of the mesoporous structure of the SBA-15 support after impregnation and calcination. In the case of monocomponent samples, CuO appeared poorly dispersed, while the Cr species (Cr2O3, mono- and polychromates) appeared highly dispersed on the surface of the SBA-15 support. The progressive addition of chromium to copper had positive effects on the average crystallite size of CuO, which decreased from ～28 nm (Cu/SBA-15) to ～3 nm (CuCr/SBA-15; Cu:Cr = 1:1), and on reducibility, as well. Metallic active phases were obtained by reducing of the oxide phases under a hydrogen flow at 350°C. By comparison to the monometallic catalysts, the reduced CuCr/SBA-15 materials were active in the hydrogenation of cinnamaldehyde and chemoselective towards cinnammyl alcohol (>50 mol%). The activity can be correlated with the particle size of copper, whereas the high selectivity to unsaturated alcohol can be associated with the presence of dual Cu 0-Crn+ sites. The Royal Society of Chemistry 2013.
Reduction of esters to ethers utilizing the powerful lewis acid BF 2OTf·OEt2
Morra, Nicholas A.,Pagenkopf, Brian L.
, p. 511 - 514 (2008)
The direct reduction of esters to their corresponding ethers has been achieved using the Lewis acid BF2OTf·OEt2 generated via anionic redistribution between TMSOTf and BF3·OEt 2 with triethylsilane acting as the
1-[3-(Diethylamino)phenyl]ethyl (DEAPE): A Photolabile Protecting Group for Hydroxyl and Carboxyl Groups
Ding, Xiong,Wang, Pengfei
, p. 10736 - 10742 (2018)
Herein we demonstrate that the photolabile protecting group (PPG), the 1-[3-(diethylamino)-phenyl]ethyl (DEAPE) group, has dramatically different photochemical properties from the parent 3-(diethylamino)benzyl (DEABn) PPG. The new PPG, derived from DEABn by adding a methyl group to the benzylic carbon, has similar reactivity as DEABn in releasing alcohol in MeCN/water; however, it is more efficient than DEABn in releasing carboxylic acid. In particular, it can release carboxylic acid efficiently in aprotic solvents and the PPG itself converts to 3-diethylaminostyrene. Photochemical removal of DEAPE can also be conveniently carried out with sunlight. The results in this work suggest that there probably exist multiple reaction pathways in cleaving the benzylic C-O bond and they can be affected by the benzylic substitution and the reaction conditions.
Highly selective reduction of cinnamaldehyde to cinnamyl alcohol using nanometric alkali metal hydrides
Fan, Yinheng,Wu, Qiang,Jin, Dan,Zou, Yunling,Liao, Shijian,Xu, Jie
, p. 488 - 489 (2006)
Under mild reaction conditions, cinnamaldehyde was reduced to cinnamyl alcohol with high selectivity and conversion using nano-LiH or nano-NaH as a reducing agent. Selectivity of 99.8% was obtained as reduced by nano-LiH with conversion of 99.4% in short
Solvolysis of benzyl alcohols and ethers in 1,2-diols and application to a deprotection of benzyl ether-type protecting groups
Miyake, Hideyoshi,Fujimura, Masahiro,Tsumura, Takatsugu,Sasaki, Mitsuru
, p. 778 - 779 (2006)
Some kinds of benzyl alcohols and ethers react with 1,2-diols, such as ethylene glycol and propylene glycol, at 130-190°C to give 2-hydroxyethyl or 2-hydroxypropyl ethers. Application of this reaction to a deprotection of benzyl ether-type protecting groups, under neutral conditions, was also described. Copyright
Intramolecular Photocycloaddition Reactions of Arylcyclopropane Tethered 1-Cyanonaphthalenes
Maeda, Hajime,Matsuda, Shoji,Mizuno, Kazuhiko
, p. 8544 - 8551 (2016)
Intramolecular photocycloaddition reactions of 1-cyanonaphthalenes bearing an arylcyclopropane containing side chain were investigated. Photoreactions of members of this family in which the arylcyclopropane moiety is bonded at the 2-position of the 1-cyanonaphthalene ring produce head-to-head and head-to-tail 1,2-[3+2] photocycloadducts. On the other hand, substances in this family containing an arylcyclopropane side chain linked to the 4-position of the cyanoarene ring undergo photoreactions to form [4+3] photocycloadducts along with novel nine-membered ring products, which are produced by photochemically induced 10 conrotatory ring opening of the initially formed intramolecular [3+2] cycloadducts. The results of solvent effects and fluorescence investigations along with those focusing on corresponding intermolecular photoreactions demonstrate that the photocycloadducts are formed predominantly through an intramolecular exciplex mechanism and that a photoinduced intramolecular electron transfer pathway via zwitterionic biradicals might be partly responsible for the process when CH3CN is the solvent.
-
Levering et al.
, p. 1190,1191 (1950)
-
Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX
Grob, Cyril A.,Waldner, Adrian
, p. 2152 - 2158 (1980)
When the Hammett-Taft equation log (k/k0) = ρq ?qi is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with ?qI except in cases where R exerts an anchimetric effect.The reaction constant ρq for 6 is -0.12 and is typical for a nucleophilic solvent assisted ks process at a primary C-atom.The tertiary halides 1 and 3, however, which reacty with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively.The reacton constant ρq is therefore a sensitive gauge for charge development in the transition state for solvolysis of satured compounds.
The catalytic behaviour in aqueous-phase hydrogenation over a renewable Ni catalyst derived from a perovskite-type oxide
Chen, Chun,Fan, Ruoyu,Gong, Wanbing,Zhang, Haimin,Wang, Guozhong,Zhao, Huijun
, p. 17276 - 17284 (2018)
Water is inevitably associated with the production of bio-derived platform molecules, but most supported metallic catalysts have poor water compatibility. Although there have been a great number of investigations regarding the hydrogenation of bio-derived unsaturated compounds in the organic phase, the reactions that proceed in water are still quite challenging. Herein, we report the synthesis of a supported nickel catalyst (Ni-LN650) by the reduction of the perovskite-type oxide LaNiO3 precursor at 650 °C. The derived catalyst affords attractive activity in the hydrogenation of furfural by using water as the reaction medium, in which furfural is completely converted into tetrahydrofurfuryl alcohol with the highest productivity of 289.7 mmol gNi?1 h?1 at 120 °C and 1 MPa of H2 within 5 h of reaction. The Ni-LN650 catalyst also exhibits good stability and renewability in a cycle test, stemming from the self-regeneration peculiarity of the perovskite-type oxide precursor. Moreover, the catalyst can also demonstrate high activity in the aqueous-phase hydrogenation of various aldehydes, alkenes and carboxylic acids in a series of experiments. Due to the merits of usability in water, the renewability and wide application scope, the Ni-LN650 catalyst can be treated as a promising candidate for the catalytic conversion of bio-derived platform molecules into high value-added fuels and chemicals.
Chemoselective reduction of carbonyl compounds with PMHS - ZnCI2
Chandrasekhar,Ravindra Reddy,Ramarao
, p. 2251 - 2254 (1997)
An inexpensive and safer reagent system comprising of PMHS and ZnCl2 has been developed for the selective reduction of carbonyl compounds to corresponding alcohols.
Synthesis, biochemical evaluation and rationalisation of the inhibitory activity of a range of 4-substituted phenyl alkyl imidazole-based inhibitors of the enzyme complex 17α-hydroxylase/17,20-lyase (P45017α)
Patel, Chirag H.,Dhanani, Sachin,Owen, Caroline P.,Ahmed, Sabbir
, p. 4752 - 4756 (2006)
We report the preliminary results of the synthesis, biochemical evaluation and rationalisation of the inhibitory activity of a number of phenyl alkyl imidazole-based compounds as inhibitors of the two components of 17α-hydroxylase/17,20-lyase (P45017α), that is, 17α-hydroxylase (17α-OHase) and 17,20-lyase (lyase). The results show that N-3-(4-bromophenyl) propyl imidazole (12) (IC50 = 2.95 μM against 17α-OHase and IC50 = 0.33 μM against lyase) is the most potent compound within the current study, in comparison to ketoconazole (KTZ) (IC50 = 3.76 μM against 17α-OHase and IC50 = 1.66 μM against lyase). Modelling of these compounds suggests that the length of the alkyl chain enhances the interaction between the inhibitor and the area of the active site corresponding to the C(3) area of the steroid backbone, thereby increasing potency.
Nitrogen-Doped Carbon Nanotube Confined Co–Nx Sites for Selective Hydrogenation of Biomass-Derived Compounds
Gong, Wanbing,Lin, Yue,Chen, Chun,Al-Mamun, Mohammad,Lu, Hai-Sheng,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
, (2019)
Biomass is the most abundant renewable resource on earth and developing high-performance nonprecious selective hydrogenation (SH) catalysts will enable the use of biomass to replace rapidly diminishing fossil resources. This work utilizes ZIF-67-derived nitrogen-doped carbon nanotubes to confine Co nanoparticles (NPs) with Co–Nx active sites as a high-performance SH catalyst. The confined Co NPs with Co–Nx exhibit excellent catalytic activity, selectivity, and stability toward a wide range of biomass-derived compounds. Such active sites can selectively hydrogenate aldehyde, ketone, carboxyl, and nitro groups of biomass-derived compounds into value-added fine chemicals with 100% selectivity. The reported approach could be adopted to create other forms of catalytically active sites from other nonprecious metals.
Application of gallium nitride nanostructures and nitrogen doped carbon spheres as supports for the hydrogenation of cinnamaldehyde
Kente, Thobeka,Dube, Sibongile M.A.,Coville, Neil J.,Mhlanga, Sabelo D.
, p. 4990 - 4995 (2013)
This paper reports on the synthesis and use of nanostructures of gallium nitride (GaN NSs) and nitrogen doped carbon spheres (NCSs) as support materials for the hydrogenation of cinnamaldehyde. This study provides the first investigation of GaN as a catalyst support in hydrogenation reactions. The GaN NSs were synthesized via chemical vapour deposition (CVD) in a double stage furnace (750 °C) while NCSs were made by CVD in a single stage furnace (950 °C) respectively. TEM analysis revealed that the GaN NSs were rod-like with average diameters of 200 nm, while the NCSs were solid with smoother surfaces, and with diameters of 450 nm. Pd nanoparticles (1 and 3% loadings) were uniformly dispersed on acid functionalized GaN NSs and NCS. The Pd nanoparticles had average diameters that were influenced by the type of support material used. The GaN NSs and NCSs were tested for the selective hydrogenation of cinnamaldehyde in isopropanol at 40 and 60 °C under atmospheric pressure. A comparative study of the activity of the nanostructured materials revealed that the order of catalyst activity was 3% Pd/GaN >3% Pd/NCSs >1% Pd/NCSs >1% Pd/GaN. However, 100% selectivity to hydrocinnamaldehyde (HCALD) was obtained with 1% Pd/GaN at reasonable conversion rates. Copyright
Kinetics and mechanistic aspects of the Heck reaction promoted by a CN-palladacycle
Consorti, Crestina S.,Flores, Fabrício R.,Dupont, Jairton
, p. 12054 - 12065 (2005)
In the Heck reaction between aryl halides and n-butyl acrylate, the palladacycle {Pd[κ1-C, κ1-N-C=(C 6H5)C(Cl)CH2NMe2](μ-Cl)}2, 1, is merely a reservoir of the catalytically active Pd(0) species [1] (Pd colloids or highly active forms of low ligated Pd(0) species) that undergoes oxidative addition of the aryl halide on the surface with subsequent detachment, generating homogeneous Pd(II) species. The main catalytic cycle is initiated by oxidative addition of iodobenzene to [1], followed by the reversible coordination of the olefin to the oxidative addition product. All the unimolecular subsequent steps are indistinguishable kinetically and can be combined in a single step. This kinetic model predicts that a slight excess of alkene relative to iodobenzene leads to a rapid rise in the Pd(0) concentration while when using a slight excess of iodobenzene, relative to alkene, the oxidative addition product is the resting state of the catalytic cycle. Competitive experiments of various bromoarenes and iodoarenes with n-butyl acrylate catalyzed by 1 and CS, CP, and NCN palladacycles gave the same p value (2.4-2.5 for Ar-Br and 1.7-1.8 for Ar-I) for all palladacycles employed, indicating that they generate the same species in the oxidative addition step. The excellent fit of the slope with the σ0 Hammett parameter and the entropy of activation of -43 ± 8 J mol-1 K -1 are consistent with an associative process involving the development of only a partial charge in the transition state for the oxidative step of iodobenzene.
Low-temperature reduction of bio-based cinnamaldehyde to α,β-(un)saturated alcohols enabled by a waste-derived catalyst
Jian, Yumei,Li, Hu,Luo, Xiaoxiang
, (2022/01/06)
A waste eggshell-derived catalyst (CaO-900) was facilely prepared and exhibited high efficiency in selective hydrogenation of bio-based cinnamaldehyde (CAL) to cinnamyl alcohol (COL) with 97% yield at 30 °C. By simply adjusting reaction temperature and time, CAL could be completely converted to 3-phenylpropanol. The predominant catalytic performance of CaO-900 could be attributed to its high alkalinity and large specific surface area. In situ Raman and theoretical calculations indicated that the priority of hydrosilylation toward CAL played a crucial role in the control of product distribution. In addition, the CaO-900 catalyst showed good recyclability.
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.
Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in a,?-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites
Zahid, Muhammad,Li, Jiang,Ismail, Ahmed,Zaera, Francisco,Zhu, Yujun
, p. 2433 - 2445 (2021/04/22)
Precious metals have been shown to play a vital role in the selective hydrogenation of a,?-unsaturated aldehydes, but still suffer from challenges to control selectivity. Herein, we have advanced the design of catalysts made out of Pt-Co intermetallic nanoparticles (IMNs) supported on a MIL-101(Cr) MOF (3%Pty%Co/MIL-101(Cr)), prepared by using a polyol reduction method, as an effective approach to enhance selectivity toward the production of a,?-unsaturated alcohol, the desired product. XRD, N2adsorption-desorption, FTIR spectroscopy, SEM, TEM, XPS, CO adsorption, NH3-TPD, XANES and EXAFS measurements were used to investigate the structure and surface properties of our 3%Pty%Co/MIL-101(Cr) catalysts. It was found that the Co-modified 3%Pty%Co/MIL-101(Cr) catalysts can indeed improve the hydrogenation of cinnamaldehyde (CAL) to cinnamyl alcohol (COL), reaching a higher selectivity under mild conditions than the monometallic Pt/MIL-101(Cr) catalysts: 95% conversion of CAL with 91% selectivity to COL can be reached with 3%Pt3%Co/MIL-101(Cr). Additionally, high conversion of furfural (97%) along with high selectivity to furfural alcohol (94%) was also attained with the 3%Pt3%Co/MIL-101(Cr) catalyst. The enhanced activity and selectivity toward the unsaturated alcohols are attributed to the electronic and geometric effects derived from the partial charge transfer between Co and Pt through the formation of uniformly dispersed Pt-Co IMNs. Moreover, various characterization results revealed that the addition of Co to the IMPs can promote the Lewis acid sites that facilitate the polarization of the charge-rich C?O bonds and their adsorptionviatheir oxygen atom, and also generate new interfacial acid sites.
