111003-03-3Relevant articles and documents
NHC-stabilised Rh nanoparticles: Surface study and application in the catalytic hydrogenation of aromatic substrates
Martinez-Espinar, Francisco,Blondeau, Pascal,Nolis, Pau,Chaudret, Bruno,Claver, Carmen,Castillón, Sergio,Godard, Cyril
, p. 113 - 127 (2017/09/08)
New Rh-NPs stabilised by N-Heterocyclic Carbenes (NHC) were synthesized by decomposition of [Rh(η3-C3H5)3] under H2 atmosphere and fully characterized. Surface studies by FT-IR and NMR spectroscopy employing isotopically labelled ligands were also performed. The Rh0.2 NPs are active catalysts in the reduction of various aromatic substrates. In the reduction of phenol, high selectivities to cyclohexanone or cyclohexanol were obtained depending on the reaction conditions. However, this catalytic system exhibited much lower activity in the hydrogenation of substituted phenols. Pyridine was easily hydrogenated under mild conditions and interestingly, the hydrogenation of 4-methyl and 4-trifluoromethylpyridine resulted slower than that of 2-methylpyridine. The hydrogenation of 1-(pyridin-2-yl)propan-2-one provided the β-enaminone 13a in high yield as a consequence of the partial reduction of the pyridine ring followed by isomerization. Quinoline could be either partially hydrogenated to 1,2,3,4-tetrahydroquinoline or fully reduced to decahydroquinoline by adjusting the reaction conditions.
A biomass phenolic compound catalytic hydrogenation method of synthesizing cyclohexyl alcohol compound (by machine translation)
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Paragraph 0030; 0033, (2017/09/26)
The invention relates to a biomass phenolic compound catalytic hydrogenation method of synthesizing cyclohexyl alcohol compound. It in order to load the noble metal palladium titanium dioxide as catalyst, biomass phenolic compound by catalytic hydrogenation synthesis of cyclohexyl alcohol compound, the obtained cyclohexyl alcohol compound can be used as fuel additives or pharmaceutical chemical intermediate, improving the utilization rate of renewable sources of energy, to relieve the energy crisis and the increasing importance attached to the problem of environmental pollution, its catalyst has simple preparation process, green environmental protection, does not pollute the environment, suitable for popularization and application. (by machine translation)
Hydrogenation of lignin-derived phenolic compounds over step by step precipitated Ni/SiO2
Shu, Riyang,Zhang, Qi,Xu, Ying,Long, Jinxing,Ma, Longlong,Wang, Tiejun,Chen, Pengru,Wu, Qingyun
, p. 5214 - 5222 (2016/02/05)
The harsh reaction conditions for the valorization of lignin-derived phenolic compounds considerably limit the efficient utilization of the lignin derivatives. Here, we put forward a high efficient and selective hydrogenation process for phenolic compounds at a mild condition over step by step precipitated Ni/SiO2 catalyst. The properties of the Ni/SiO2 catalysts by different preparation methods were detailedly compared using various characterization measurements. Catalytic activity of the catalysts was tested by the hydrogenation of guaiacol, and the results showed that guaiacol could be completely converted into cyclohexanol with 99.9% selectivity at 120 °C, 2 MPa H2 atmosphere for 2 h. Other typical lignin-derived phenolic compounds also had excellent hydrogenation performance and great energy efficiency. Catalyst characterization results demonstrated that the high catalytic activity of the step by step precipitated Ni/SiO2 was mainly ascribed to its polyporous spherical structure, which led to the large specific surface area and high nickel dispersion. The appropriate acidity of the catalyst also promoted the catalytic performance significantly. Furthermore, the catalyst exhibited an excellent recyclability, where no significant loss of the catalytic activity was showed out after 3 runs.
Catalytic hydrogenation of aromatic rings catalyzed by Pd/NiO
Wang, Yanan,Cui, Xinjiang,Deng, Youquan,Shi, Feng
, p. 2729 - 2732 (2014/01/06)
A simple and efficient heterogeneous palladium catalyst was prepared for aromatic ring hydrogenation. The catalyst was prepared by a reduction-deposition method and exhibited high activity and selectivity for the hydrogenation of a variety of substituted aromatic compounds to the corresponding cyclohexane and cyclohexanol derivatives with up to 99% yields. The catalyst was characterized by BET, TEM, XRD, XPS and ICP. Meanwhile the reusability of the catalyst was investigated, and it can be reused for several runs without significant deactivation.
An efficient cleavage of the aryl ether C-O bond in supercritical carbon dioxide-water
Chatterjee, Maya,Ishizaka, Takayuki,Suzuki, Akira,Kawanami, Hajime
supporting information, p. 4567 - 4569 (2013/06/04)
A simple and highly efficient Rh/C catalyzed route for the cleavage of the C-O bond of aromatic ether at 80 °C in the presence of 0.5 MPa of H 2 in the scCO2-water medium is reported; CO2 pressure and water play a key role under the tested conditions.
Directive effect of the 2- and 3-axial hydroxy groups that appeared in the complex metal hydride reduction of cyclohexanones
Senda,Kikuchi,Inui,Itoh
, p. 237 - 242 (2007/10/03)
A directive effect of the 2-axial hydroxy group appeared in the LiAlH4, NaBH4, and Zn(BH4)2 reduction of cyclohexanone, while the 3-axial hydroxy group exhibited a steric hindrance. The distance between the carbonyl carbon and the hydroxy group interacting with the hydride reagent was responsible for such a difference. In the reduction of Na[B(OAc)3H], the 2- and 3-axial hydroxycyclohexanones gave the products obtained by the hydride approaching from the side of the hydroxy group. The key point of the stereoselectivity was the formation of Na[B(OAc)2(OR)H, which was more reactive than the parent hydride, by exchanging the acetate ion with the alkoxide. Although the reduction was performed under the condition that the hydride/substrate ratio was 1, the conversion of the hydroxy ketone to an alcohol were 4, NaBH4, and Zn(BH4)2 reductions in tetrahydrofuran. The conversions in the NaBH4 reduction in ethanol were > 90%.
Total Synthesis of (+/-)-Pyridoxatin
Snider, Barry B.,Lu, Qing
, p. 8065 - 8070 (2007/10/02)
An efficient two-step route to pyridoxatin analogues 13 and 15 has been developed.Condensation of 4-hydroxypyridone (4) with citronellal (10) affords o-quinone methide intermediate 11, which reacts further to give inverse electron demand Diels-Alder adducts 12 and 16 and ene adduct 14.Oxidation of 12 and 14 with MoO5 by Sammes' procedure completes the synthesis of 13 and 15.Using this approach, the first total synthesis of (+/-)-pyridoxatin (1) has been carried out in seven steps from cis-2,4-dimethylcyclohexanone (21).The key step is the condensation of 4-hydroxypyridone (4) with the allylic silane aldehyde 26 to give 35percent of cyclohexylpyridones 2 and 30.
Cycloalkyl esters of mercaptoalkanoic acids
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, (2008/06/13)
Described are the cycloalkyl esters of mercaptoalkanoic acids defined according to the structure: STR1 wherein R1 represents hydrogen or methyl; R2 represents mono C1 -C4 alkyl substituted or unsubstituted C5 -C8 cycloalkyl; R3 represents hydrogen or methyl; and N represents 0, 1 or 2 and uses thereof in augmenting or enhancing the aroma or taste of foodstuffs.
