10281-53-5Relevant articles and documents
Selective reduction of mono- and disubstituted olefins by NaBH4 and catalytic RuCl3
Sharma, Pawan K.,Kumar, Surender,Kumar, Pawan,Nielsen, Poul
, p. 8704 - 8708 (2007)
Direct use of the relatively inexpensive reagent, RuCl3 × H2O, as a catalyst for the reductions of olefins in the presence of water is reported. The combination of cheap and readily available sodium borohydride and a catalytic amount of RuCl3 × H2O selectively reduces mono- and disubstituted olefins, whereas trisubstituted olefins, unless activated, and benzyl ethers remain inert.
Iridium(I) complexes with anionic N-heterocyclic carbene ligands as catalysts for the hydrogenation of alkenes in nonpolar media
Kolychev, Eugene L.,Kronig, Sabrina,Brandhorst, Kai,Freytag, Matthias,Jones, Peter G.,Tamm, Matthias
, p. 12448 - 12459 (2013)
A series of lithium complexes of anionic N-heterocyclic carbenes that contain a weakly coordinating borate moiety (WCA-NHC) was prepared in one step from free N-heterocyclic carbenes by deprotonation with n-butyl lithium followed by borane addition. The reaction of the resulting lithium-carbene adducts with [M(COD)Cl]2 (M = Rh, Ir; COD = 1,5-cyclooctadiene) afforded zwitterionic rhodium(I) and iridium(I) complexes of the type [(WCA-NHC)M(COD)], in which the metal atoms exhibit an intramolecular interaction with the N-aryl groups of the carbene ligands. For M = Rh, the neutral complex [(WCA-NHC)Rh(CO)2] and the ate complex (NEt4)[(WCA-NHC) Rh(CO)2Cl] were prepared, with the latter allowing an assessment of the donor ability of the ligand by IR spectroscopy. The zwitterionic iridium-COD complexes were tested as catalysts for the homogeneous hydrogenation of alkenes, which can be performed in the presence of nonpolar solvents or in the neat alkene substrate. Thereby, the most active complex showed excellent stability and activity in hydrogenation of alkenes at low catalyst loadings (down to 10 ppm).
Magnetically recyclable Ru immobilized on amine-functionalized magnetite nanoparticles and its high selectivity to prepare cis-pinane
Liu, Yue,Li, Lu,Liu, Shiwei,Xie, Congxia,Yu, Shitao
, p. 269 - 275 (2016)
cis-Pinane was efficient and selective prepared through the hydrogenation of α-pinene base on Ru nanoparticles stabilized by amine-functionalized magnetite nanoparticles (Fe3O4/NH2/Ru). The effects o`f changing carbon chain length on amine-functionalized catalyst formation have also been investigated. The characterization results showed that Ru nanoparticles could be efficient loaded by 1, 6-hexanediamine functionalized magnetite nanoparticles. At the same time, Fe3O4/1, 6-hexanediamine/Ru had good superparamagnetic properties and that the introduction of the amine-functionalized improved the monodispersity, morphological regularity and size uniformity of the Ru nanoparticles. The Fe3O4/1, 6-hexanediamine/Ru catalyst was completely recoverable with the simple application of an external magnetic field and the catalytic efficiency showed no obvious loss for the hydrogenation of α-pinene even after ten repeated cycles.
Hydrogenation and Skeleton Rearrangements of α-Pinene on Heterogeneous Catalysts
Bazhenov,Kas'yanova,Bokin,Kutepov,Khazipova,Travkin,Shchadneva,Khusnutdinov,Dzhemilev
, p. 234 - 237 (2003)
Hydrogenation and isomerization of α-pinene on heterogeneous catalysts were studied, and conditions were found for hydrogenation of pinene to cis-pinane on nickel catalysts and for its dehydrogenation to p-cymene on decationized zeolite Y.
Rate constant of the α-pinene + atomic hydrogen reaction at 295 K
Vinckier,Van Hoof
, p. 527 - 534 (1994)
The rate constant of the reaction of α-pinene with atomic hydrogen was determined at 295 K using the fast-flow reactor technique directly coupled to a mass spectrometric detection technique. The value was found to be equal to (9.8 ± 3.3) × 10-13 cm3 molecules-1 s-1 and independent of the helium pressure between 1 and 2 torr. The major reaction product formed is pinane showing that the stabilization of the adduct radical C10H17, followed by a subsequent hydrogen atom addition step, is the important reaction route.
Postassembly Transformation of a Catalytically Active Composite Material, Pt@ZIF-8, via Solvent-Assisted Linker Exchange
Stephenson, Casey J.,Hupp, Joseph T.,Farha, Omar K.
, p. 1361 - 1363 (2016)
2-Methylimidazolate linkers of Pt@ZIF-8 are exchanged with imidazolate using solvent-assisted linker exchange (SALE) to expand the apertures of the parent material and create Pt@SALEM-2. Characterization of the material before and after SALE was performed. Both materials are active as catalysts for the hydrogenation of 1-octene, whereas the hydrogenation of cis-cyclohexene occurred only with Pt@SALEM-2, consistent with larger apertures for the daughter material. The largest substrate, β-pinene, proved to be unreactive with H2 when either material was employed as a candidate catalyst, supporting the contention that substrate molecules, for both composites, must traverse the metal-organic framework component in order to reach the catalytic nanoparticles.
Hydrogenation of hydrophobic substrates catalyzed by gold nanoparticles embedded in Tetronic/cyclodextrin-based hydrogels
Chevry,Menuel,Léger,No?l,Monflier,Hapiot
, p. 9865 - 9872 (2019)
Hydrogenation of alkenes, alkynes and aldehydes was investigated under biphasic conditions using Au nanoparticles (AuNP) embedded into combinations of α-cyclodextrin (α-CD) and a poloxamine (Tetronic90R4). Thermo-responsive AuNP-containing α-CD/Tetronic90R4 hydrogels are formed under well-defined conditions of concentration. The AuNP displayed an average size of ca. 7 nm and a narrow distribution, as determined by TEM. The AuNP/α-CD/Tetronic90R4 system proved to be stable over time. Upon heating above the gel-to-sol transition temperature, the studied catalytic system allowed hydrogenation of a wide range of substrates such as alkenes, alkynes and aldehydes under biphasic conditions. Upon repeated heating/cooling cycles, the Au NP/α-CD/Tetronic90R4 catalytic system could be recycled several times without a significant decline in catalytic activity.
Sodium borohydride-nickel chloride hexahydrate in EtOH/PEG-400 as an efficient and recyclable catalytic system for the reduction of alkenes
Li, Kaoxue,Liu, Chuanchao,Wang, Kang,Ren, Yang,Li, Fahui
, p. 7761 - 7764 (2018)
An efficient, safe and one-pot convenient catalytic system has been developed for the reduction of alkenes using NaBH4-NiCl2·6H2O in EtOH/PEG-400 under mild conditions. In this catalytic system, a variety of alkenes (including trisubstituted alkene α-pinene) were well reduced and the Ni catalyst could be recycled.
Room Temperature Iron-Catalyzed Transfer Hydrogenation and Regioselective Deuteration of Carbon-Carbon Double Bonds
Espinal-Viguri, Maialen,Neale, Samuel E.,Coles, Nathan T.,MacGregor, Stuart A.,Webster, Ruth L.
, p. 572 - 582 (2019)
An iron catalyst has been developed for the transfer hydrogenation of carbon-carbon multiple bonds. Using a well-defined β-diketiminate iron(II) precatalyst, a sacrificial amine and a borane, even simple, unactivated alkenes such as 1-hexene undergo hydrogenation within 1 h at room temperature. Tuning the reagent stoichiometry allows for semi- and complete hydrogenation of terminal alkynes. It is also possible to hydrogenate aminoalkenes and aminoalkynes without poisoning the catalyst through competitive amine ligation. Furthermore, by exploiting the separate protic and hydridic nature of the reagents, it is possible to regioselectively prepare monoisotopically labeled products. DFT calculations define a mechanism for the transfer hydrogenation of propene with nBuNH2 and HBpin that involves the initial formation of an iron(II)-hydride active species, 1,2-insertion of propene, and rate-limiting protonolysis of the resultant alkyl by the amine N-H bond. This mechanism is fully consistent with the selective deuteration studies, although the calculations also highlight alkene hydroboration and amine-borane dehydrocoupling as competitive processes. This was resolved by reassessing the nature of the active transfer hydrogenation agent: experimentally, a gel is observed in catalysis, and calculations suggest this can be formulated as an oligomeric species comprising H-bonded amine-borane adducts. Gel formation serves to reduce the effective concentrations of free HBpin and nBuNH2 and so disfavors both hydroboration and dehydrocoupling while allowing alkene migratory insertion (and hence transfer hydrogenation) to dominate.
DEUTERATION IN A CHROMATO-MASS SPECTROMETER INLET SYSTEM IN A STUDY OF THE FRAGMENTATION MECHANISMS OF CYCLOBUTANE HYDROCARBONS
Mikaya, A. N.,Romanov, G. D.,Zaikin, V. G.,Vdovin, V. M.
, p. 2228 - 2231 (1985)
-
Methylated cyclodextrins: An efficient protective agent in water for zerovalent ruthenium nanoparticles and a supramolecular shuttle in alkene and arene hydrogenation reactions
Denicourt-Nowicki, Audrey,Ponchel, Anne,Monflier, Eric,Roucoux, Alain
, p. 5714 - 5719 (2007)
Zerovalent ruthenium(0) nanoparticles in the size range of 2.5 nm were easily prepared by chemical reduction of ruthenium salt with an excess amount of sodium borohydride and were efficiently stabilized by methylated cyclodextrins. The optimization of the catalytic system has been carried out in terms of stability and catalytic activity, considering the hydrogenation of olefinic compounds under biphasic liquid-liquid conditions. Efficient and controlled chemoselectivities were obtained in the hydrogenation of arene derivatives by the relevant choice of cavity and methylation degree of the cyclodextrins. Finally, the hydrogenation of α- and β-pinenes leads to the major formation of cis-pinanes, interesting synthons for fine chemistry, with high diastereoisomeric excesses. This journal is The Royal Society of Chemistry.
Synthesis of silanized magnetic Ru/Fe3O4@SiO2 nanospheres and their high selectivity to prepare: Cis -pinane
Liu, Yue,Li, Lu,Liu, Shiwei,Xie, Congxia,Yu, Shitao
, p. 81310 - 81317 (2016)
(3-Aminopropyl)-triethoxysilane (APTS) and (3-mercaptopropyl)-trimethoxysilane (MPTS) grafted SiO2-coated iron oxide (Fe3O4@SiO2) magnetic supports were prepared. Various noble metal nanoparticles such as Ru, Pt, Rh and Pd were directly grown on the surfaces of the magnetic supports with ultrasmall and nearly monodisperse sizes, especially the APTS grafted Fe3O4@SiO2 (Fe3O4@SiO2/APTS) nanospheres. The Fe3O4@SiO2/APTS/Ru catalyst demonstrated a high catalytic activity towards the hydrogenation of α-pinene to form cis-pinane. The conversion of α-pinene was 99.1% and the selectivity for cis-pinane reached 97.6% at 120 °C after 4 h. The Fe3O4@SiO2/APTS/Ru catalyst was easily separated from the reaction mixture when applying an external magnetic field, and the separated Fe3O4@SiO2/APTS/Ru had good reusability. After being reused eight times, the α-pinene conversion and the cis-pinane selectivity also can reach 97.8% and 96.9%, respectively.
Highly selective and recyclable hydrogenation of α-pinene catalyzed by ruthenium nanoparticles loaded on amphiphilic core–shell magnetic nanomaterials
Wu, Fang-Zhu,Yu, Feng-Li,Yuan, Bing,Xie, Cong-Xia,Yu, Shi-Tao
, (2019)
A multifunctional nanomaterial (Fe3O4@SiO2@CX@NH2) comprising a magnetic core, a silicon protective interlayer, and an amphiphilic silica shell is successfully prepared. Ru nanoparticles catalyst loaded on Fe3O4@SiO2@CX@NH2 is used in hydrogenation of α-pinene for the first time. The novel nanomaterial with amphipathy can be used as a solid foaming agent to increase gas–liquid–solid three-phase contact and accelerate the reaction. Under the mild conditions (40?°C, 1?MPa H2, 3?h), 99.9% α-pinene conversion and 98.9% cis-pinane selectivity are obtained, which is by far the best results reported. Furthermore, the magnetic nanocomposite catalyst can be easily separated by an external magnet and reused nine times with high selectivity maintaining.
The Exploration of Sensitive Factors for the Selective Hydrogenation of α-Pinene Over Recyclable Ni-B/KIT-6 Catalyst
Deng, Qiao,Hu, Tianding,Huang, Jinyan,Huang, Pengpeng,Jiang, Lihong,Shan, Shaoyun,Su, Hongying,Wang, Yaming,Yang, Wenjuan,Zheng, Yane,Zhi, Yunfei
, (2021/10/08)
The supported Ni-B/KIT-6 amorphous alloy catalyst was prepared by chemical reduction method for the hydrogenation reaction of α-pinene. The catalyst was characterized by XRD, BET, SEM–EDS, TEM, XPS, ICP and DLS, the influences of single factor of catalyst on its structure, morphology and performance were investigated and analyzed. It was found that the amount of Ni loading, preparation pH and B/Ni molar ratio had great effects on the reduction amount, dispersion and specific surface area of the catalyst, resulted in affecting the catalytic performance of the catalyst. The optimum synthesis conditions were at m(Ni2+)/m(KIT-6) = 1:3, pH 13 and n(B)/n(Ni) = 1.5, obtaining a 90.62% conversion of α-pinene and 97.67% selectivity of cis-pinane. In addition, the catalysts also exhibited better repeatability and stability. Graphic Abstract: [Figure not available: see fulltext.]
