106-22-9Relevant articles and documents
Electrochemical hydrogenation of citral 1. The role of the copper cathode in the electroreduction of citral
Korotyaeva, L. M.,Rubinskaya, T. Ya.,Gultyai, V. P.
, p. 1830 - 1834 (1993)
Alcohols (citronellol and isomeric nerol and geraniol) are the main products of the electroreduction of citral at the copper cathode in the presence in the AcOH in a water-DMF medium.It has been suggested that under the conditions of the electrolysis at the hydrogen reduction potential (E = -1.2 V) electroreduction of citral occurs according to the electrochemical hydrogenation mechanism.The total yield of the alcohols and the selectivity of the process depend on the preliminary treatment of the cathode.The electroreduction of citral at a mechanically cleaned cathode gives alcohols in 54percent total yield, and unsaturated alcohols are the prevailing products.Preliminary annealing of the cathode results in an increase in the total yield of alcohols in the electrolysis to 86percent and in the predominant formation of citronellol. - Key words: copper cathode, citral, citronellol, electrochemical hydrogenation, electroreduction, recrystallization.
Chemoselective Hydrogenation of Aldehydes under Mild, Base-Free Conditions: Manganese Outperforms Rhenium
Glatz, Mathias,St?ger, Berthold,Himmelbauer, Daniel,Veiros, Luis F.,Kirchner, Karl
, p. 4009 - 4016 (2018)
Several hydride Mn(I) and Re(I) PNP pincer complexes were applied as catalysts for the homogeneous chemoselective hydrogenation of aldehydes. Among these, [Mn(PNP-iPr)(CO)2(H)] was found to be one of the most efficient base metal catalysts for this process and represents a rare example which permits the selective hydrogenation of aldehydes in the presence of ketones and other reducible functionalities, such as C=C double bonds, esters, or nitriles. The reaction proceeds at room temperature under base-free conditions with catalyst loadings between 0.1 and 0.05 mol% and a hydrogen pressure of 50 bar (reaching TONs of up to 2000). A mechanism which involves an outer-sphere hydride transfer and reversible PNP ligand deprotonation/protonation is proposed. Analogous isoelectronic and isostructural Re(I) complexes were only poorly active.
Hydrogenation of alkenes with rhodium nanoparticles supported on SBA-15
Bhorali, Nayanmoni,Ganguli, Jatindra Nath
, p. 276 - 281 (2013)
Rhodium nanoparticles were prepared by chemical reduction of RhCl 3·3H2O in presence of polyvinyl pyrrolidone and then immobilized on SBA-15 by impregnation. The catalyst was used for hydrogenation of unsaturated hydrocarbons at room temperature. The progress of the reaction was monitored by GC-MS and 100 % conversion was achieved in all cases.
Reduction of carbonyl compounds by using polymethylhydrosiloxane: Reactivity and selectivity
Kobayashi, Yuichi,Takahisa, Eisuke,Nakano, Miwa,Watatani, Kengo
, p. 1627 - 1634 (1997)
Reduction of aldehydes and ketones with PMHS [Me3SiO-(SiMe(H)O)(n)-SiMe3] proceeded smoothly in the presence of Bu4NF at -70°C or 0°C within 60 min in THF. High stereo- and chemoselectivities as well as functional group tolerance of this system are also presented.
Hydrogenation of aldehydes and ketones to corresponding alcohols with methylamine borane in neat water
Duan, Yifan,Bai, Ruijiao,Tian, Jun,Chen, Ligong,Yan, Xilong
, p. 2555 - 2564 (2014)
GRAPHICAL ABSTRACT Chemoselective hydrogenation of various aldehydes and ketones with methylamine borane (MeAB) in neat water was investigated. MeAB is suitable for green organic reactions, for MeAB is a nontoxic, environmentally benign, and easily handled reagent. Aldehydes were selectively and rapidly hydrogenated in excellent yields (86-97%) for 30 min, but hydrogenation of aromatic ketones needed over 20 h at room temperature because of their poor water solubility and steric hindrance. Thus we investigated polyethylene glycol (PEG400) and acidic cation-exchange D072 resin as catalysts to accelerate the hydrogenation reaction of aromatic ketones and achieved excellent yields within several hours. PEG 400 and D072 resin are both suitable for green organic reactions. The D072 resin was reused up to four times without any significance loss in activity.
Neilan,J.P. et al.
, p. 3455 - 3460 (1976)
Liquid-phase citral hydrogenation over SiO2-supported Group VIII metals
Singh, Utpal K.,Vannice, M. Albert
, p. 73 - 84 (2001)
Citral hydrogenation was studied over SiO2-supported Group VIII metals at 300 K and 1 atm in the absence of all transport limitations as verified by the Madon-Boudart test and the Weisz-Prater criterion. The initial turnover frequency (TOF) for
Transfer of Hydrogen from Alcohols. Catalysis by Compounds of Tin
Wuest, James D.,Zacharie, Boulos
, p. 166 - 168 (1984)
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Hydrogenation of citral using monometallic Pt and bimetallic Pt-Ru catalysts on a mesoporous support in supercritical carbon dioxide medium
Chatterjee,Zhao,Ikushima
, p. 459 - 466 (2004)
Supercritical carbon dioxide was shown to be a suitable reaction medium for the highly efficient hydrogenation of citral using monometallic Pt and bimetallic Pt-Ru supported on a mesoporous material, MCM-48, as catalyst. A remarkable change in the product distribution was observed after the addition of Ru to the monometallic Pt catalyst in supercritical carbon dioxide. The monometallic Pt catalyst was found to be highly selective to the unsaturated alcohol (geraniol + nerol) at a temperature of 323 K within 2 h whereas the bimetallic catalyst becomes selective to the partially saturated aldehyde (citronellal) under the same reaction conditions. Phase behavior plays an important role in the product distribution. Highest conversion and high selectivity to citronellal were achieved in the homogeneous phase for the Pt-Ru catalyst while on the other hand the unsaturated alcohol (geraniol + nerol) was produced in the heterogeneous phase for the monometallic Pt catalyst. An XPS study offers strong evidence of the electronic modification of Pt after the addition of Ru in the bimetallic catalyst. The change in product distribution on the Pt-Ru bimetallic catalyst may be explained by the appreciable interaction between the medium and the metal particles promoted by the presence of metallic Ru.
Biomass- And calcium carbide-based recyclable polymers
Metlyaeva, Svetlana A.,Rodygin, Konstantin S.,Lotsman, Kristina A.,Samoylenko, Dmitriy E.,Ananikov, Valentine P.
, p. 2487 - 2495 (2021)
Biomass is a renewable source of valuable feedstock for the chemical industry of the future. A promising approach to the utilization of valuable components of biomass is the synthesis of monomers and polymers, if the overall technology is designed for a clean cycle without pollution of the environment with newly created polymers. In this work, we have developed a methodology for the recycling of polymers based on biomass and calcium carbide. First, we modified a series of biomass-derived terpene alcohols with calcium carbide followed by polymerization of the isolated vinyl ethers. Then, to study the recycling potential, the obtained polymers were subjected to pyrolysis at moderate temperatures (200-450 °C). The pyrolysis products were analyzed using TGA-MS, GC-MS, and NMR, and it was found that the polymers can be transformed quite easily. The products of the pyrolysis consisted of the starting terpenols, as well as the corresponding non-toxic ketones or aldehydes: up to 87% of the starting alcohol or up to 100% of the total sum of alcohol + aldehyde or alcohol + ketone (GC-yields). Then, the reaction mixture was hydrogenated and resulted in the formation of starting alcohol only. According to the studied pathway of polymers re-building, a terpene fragment attached to the main polyethylene chain through an oxygen atom promotes the transformation of the obtained polymers. Thus, the products of pyrolysis are environmentally friendly and can be reused in the further synthesis of monomers. The developed system has shown a unique assembling/disassembling ability and advances the concept of reusable bio-derived high value-added materials.
Chemoselective Pt-catalysts supported on carbon-TiO2 composites for the direct hydrogenation of citral to unsaturated alcohols
Bailón-García, Esther,Carrasco-Marín, Francisco,Pérez-Cadenas, Agustín F.,Maldonado-Hódar, Francisco J.
, p. 701 - 711 (2016)
A series of carbon xerogels-TiO2 composites with different TiO2 contents were prepared, exhaustively characterized and used as a Pt-support to develop selective hydrogenation catalysts. The carbon phase in the composite hinders the TiO2 crystal growth and the transformation to rutile during thermal treatments. Textural, chemical and catalytic properties are determined by the TiO2 content, with an optimum around 40 wt.% of TiO2 content. The mesoporosity of the supports, the Pt-dispersion and Pt-support interactions are favoured in this sense. During the H2-pretreatment, the Pt and TiO2 phases were simultaneously reduced and the formation of oxygen vacancies leads to the mobility of Pt-species inside the TiO2 structure, avoiding sintering in surface and strongly improving both catalytic activity and selectivity. The catalytic performance was discussed on the basis of the sample characteristics. Unsaturated alcohols were obtained as main reaction products in all cases, being the only product in the case of the optimized catalyst.
Transfer hydrogenation of carbonyl compounds catalyzed by ruthenium nanoparticles stabilized on nanocrystalline magnesium oxide by ionic liquids
Lakshmi Kantam,Sudarshan Reddy,Pal, Ujjwal,Sreedhar,Bhargava
, p. 2231 - 2235 (2008)
Transfer hydrogenation of various carbonyl compounds was achieved in excellent yields by ruthenium nanoparticles stabilized on the nanocrystalline magnesium oxide by the incorporation of choline hydroxide, a basic ionic liquid. The procedure is simple, efficient and the catalyst can be recycled five times.
Electrochemical hydrogenation of citral 4. * Role of the acid component in electrochemical hydrogenation
Korotayeva,Rubinskaya,Gultyai
, p. 459 - 462 (1997)
The effect of the nature and concentration of the acid component on the yield and ratio of the products of electrocatalytic hydrogenation of citral was studied. The use of weak organic acids (e.g., AcOH) in amounts that are stoichiometric for hydrogenation of conjugated double bonds was shown to be advantageous.
Selective Hydrogenation of Citral on Pt-Containing Catalysts at Room Temperature and Atmospheric Pressure
Vikanova,Redina
, p. 2566 - 2569 (2019)
Abstract: It is shown that the 1% Pt/CeO2–ZrO2 (1% Pt/CZ) catalytic system allows selective hydrogenation of citral with a 94% conversion and a selectivity towards unsaturated alcohols of 59% at room temperature and atmospheric pressure. The effect of addition of alkali to the reaction mixture on the yield of the target products is studied, and the optimum conditions of the reaction are determined.
Electrochemical hydrogenation of citral 2. The effect of the components of the medium on the process of electrochemical reduction at a copper cathode
Rubinskaya, T. Ya.,Korotayeva, L. M.,Gul'tyai, V. P.
, p. 1835 - 1838 (1993)
The factors (concentration of citral, composition of the solvent, AcOH : citral ratio) affecting electrochemical hydrogenation of citral at an annealed copper cathode have been determined.The highest total yield (94percent) of the alcohols (nerol, geraniol, citranellol) with a considerable predominance of the latter is achieved at 40percent DMF in water, citral concentration 0.02 M, and AcOH : citral ratio = 10 : 1.The transition to purely organic or purely aqueous media leads to a decrease in both the total yield of the alcohols and the selectivity of the process. - Key words: copper cathode, citral, citronellol, electrochemical hydrogenation.
Highly Efficient and Selective Hydrogenation of Aldehydes: A Well-Defined Fe(II) Catalyst Exhibits Noble-Metal Activity
Gorgas, Nikolaus,St?ger, Berthold,Veiros, Luis F.,Kirchner, Karl
, p. 2664 - 2672 (2016)
The synthesis and application of [Fe(PNPMe-iPr)(CO)(H)(Br)] and [Fe(PNPMe-iPr)(H)2(CO)] as catalysts for the homogeneous hydrogenation of aldehydes is described. These systems were found to be among the most efficient catalysts for this process reported to date and constitute rare examples of a catalytic process which allows selective reduction of aldehydes in the presence of ketones and other reducible functionalities. In some cases, TONs and TOFs of up to 80000 and 20000 h-1, respectively, were reached. On the basis of stoichiometric experiments and computational studies, a mechanism which proceeds via a trans-dihydride intermediate is proposed. The structure of the hydride complexes was also confirmed by X-ray crystallography.
An efficient reduction system - NiCl2·6H2O-Zn/DMF-H2O for conversion of aldehydes to alcohols
Baruah, Robindra N.
, p. 5417 - 5418 (1992)
Aldehydes were efficiently converted to the corresponding alcohols at room temperature, with NiCl2·6H2O-Zn/DMF-H2O system.
Tuning selectivity in terpene chemistry: Selective hydrogenation versus cascade reactions over copper catalysts
Zaccheria,Ravasio,Fusi,Rodondi,Psaro
, p. 1267 - 1272 (2005)
The selectivity of Cu/Al2O3 under very mild catalytic hydrogenation conditions can be tuned only by switching the solvent. Geraniol can be converted in a one-pot one-step process into a mixture of citronellol and menthol in hydrocarbon solvents or reduced to citronellol with 98% selectivity in 2-propanol without any additive. Both reactions can be applied to essential oils or synthetic mixtures containing geraniol, citronellal and nerol.
Magnetic nickel ferrite nanoparticles as highly durable catalysts for catalytic transfer hydrogenation of bio-based aldehydes
He, Jian,Yang, Song,Riisager, Anders
, p. 790 - 797 (2018)
Magnetic nickel ferrite (NiFe2O4) nanoparticles were exploited as stable and easily separable heterogeneous catalysts for catalytic transfer hydrogenation (CTH) of furfural to furfuryl alcohol with 2-propanol as both the hydrogen source and the solvent providing 94% product yield at 180 °C after 6 h of reaction. The magnetic properties of the catalysts provided facile recovery using an external magnet after reaction allowing it to be reused in five reaction cycles without loss of catalytic performance. Importantly, the NiFe2O4 nanoparticles were also applicable to CTH of other alkenyl/allyl/aromatic aldehydes affording over 94% selectivity towards the targeted alcohol products, thus being attractive as highly universal catalysts for CTH of aldehydes.
Direct synthesis of hybrid layered double hydroxide-carbon composites supported Pd nanocatalysts efficient in selective hydrogenation of citral
Han, Ruirui,Nan, Chunshi,Yang, Lan,Fan, Guoli,Li, Feng
, p. 33199 - 33207 (2015)
This present study reports a facile one-pot strategy for the direct synthesis of hybrid layered double hydroxide (LDH)-carbon composites supported palladium nanocatalysts by the in situ reduction of PdCl42--intercalated MgAl-LDH combined with amorphous carbon under mild hydrothermal conditions. The results demonstrated that most of the Pd(II) species intercalated in the interlameller space of MgAl-LDH could be reduced in situ to metallic Pd0 species, and simultaneously, the hybrid structure of the LDH-C composites facilitated the formation of uniform Pd nanoparticles with small diameter, as well as the strong metal-support interactions. Furthermore, with the decreasing proportion of the LDH component in LDH-C composites, the average diameter of Pd nanoparticles decreased progressively and the metal-support interactions were weakened. The as-formed supported Pd nanocatalyst with Pd loading of 5.5 wt% was found to show a superior catalytic activity in the liquid-phase selective hydrogenation of citral than other supported Pd nanocatalysts, while the one with the Pd loading of 2.7 wt% yielded a much higher yield of citronellal (~80.0%) at 100% conversion. The catalytic performance of Pd nanocatalysts was proposed to be mainly related to both the metal-support interactions and the compositions of hybrid LDH-C composite supports.
Highly efficient Meerwein-Ponndorf-Verley reductions over a robust zirconium-organoboronic acid hybrid
Song, Jinliang,Hua, Manli,Huang, Xin,Visa, Aurelia,Wu, Tianbin,Fan, Honglei,Hou, Minqiang,Zhang, Zhaofu,Han, Buxing
, p. 1259 - 1265 (2021)
The Meerwein-Ponndorf-Verley (MPV) reaction is an attractive approach to selectively reduce carbonyl groups, and the design of advanced catalysts is the key for these kinds of interesting reactions. Herein, we fabricated a novel zirconium organoborate using 1,4-benzenediboronic acid (BDB) as the precursor for MPV reduction. The prepared Zr-BDB had excellent catalytic performance for the MPV reduction of various biomass-derived carbonyl compounds (i.e., levulinate esters, aldehydes and ketones). More importantly, the number of borate groups on the ligands significantly affected the catalytic activity of the Zr-organic ligand hybrids, owing to the activation role of borate groups on hydroxyl groups in the hydrogen source. Detailed investigations revealed that the excellent performance of Zr-BDB was contributed by the synergetic effect of Zr4+and borate. Notably, this is the first work to enhance the activity of Zr-based catalysts in MPV reactions using borate groups.
Triphenylphosphine Dibromide: Effective and Selective Reagent for the Cleavage of Acetals
Wagner, Alain,Heitz, Marie-Paule,Mioskowski, Charles
, p. 1619 - 1620 (1989)
Triphenylphosphine dibromide (PPh3Br2) is a mild and highly effective reagent for hydrolysis of various acetals in dichloromethane at low temperature.
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Rennie,Cooke,Finlayson
, p. 348 (1920)
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SELECTIVE REDUCTION OF ALDEHYDES
Sorrell, Thomas N.,Pearlman, Paul S.
, p. 3963 - 3964 (1980)
Tetraethylammonium borohydride performs the selective reduction of aldehydes under mild conditions.
On-the-fly Catalyst Accretion and Screening in Chemoselective Flow Hydrogenation
Giziński, Damian,B?achucki, Wojciech,?r?bowata, Anna,Zienkiewicz-Machnik, Ma?gorzata,Goszewska, Ilona,Matus, Krzysztof,Lisovytskiy, Dmytro,Pisarek, Marcin,Szlachetko, Jakub,Sá, Jacinto
, p. 3641 - 3646 (2018)
Herein, it is reported an on-the-fly accretion/reaction protocol to evaluate the structure-performance relationship in the chemoselective flow citral hydrogenation over Ni-based catalysts. Based on the methodology one was able to determine Ni nanoparticles ideal average size (ca. 9 nm), in a rapid and facile manner. The methodology offers a simple workflow, cost-effective and adaptable strategy for process intensification and optimization.
Continuous synthesis of menthol from citronellal and citral over Ni-beta-zeolite-sepiolite composite catalyst
Er?nen, Kari,M?ki-Arvela, P?ivi,Martinez-Klimov, Mark,Muller, Joseph,Murzin, Dmitry Yu.,Peurla, Markus,Simakova, Irina,Vajglova, Zuzana
, (2022/04/03)
One-pot continuous synthesis of menthols both from citronellal and citral was investigated over 5 wt% Ni supported on H-Beta-38-sepiolite composite catalyst at 60–70 °C under 10–29 bar hydrogen pressure. A relatively high menthols yield of 53% and 49% and stereoselectivity to menthol of 71–76% and 72–74% were obtained from citronellal and citral respectively at the contact time 4.2 min, 70 °C and 20 bar. Citral conversion noticeably decreased with time-on-stream under 10 and 15 bar of hydrogen pressure accompanied by accumulation of citronellal, the primary hydrogenation product of citral, practically not affecting selectivity to menthol. A substantial amount of defuctionalization products observed during citral conversion, especially at the beginning of the reaction (ca. 1 h), indicated that all intermediates could contribute to formation of menthanes. Ni/H-Beta-38-sepiolite composite material prepared by extrusion was characterized by TEM, SEM, XPS, XRD, ICP-OES, N2 physisorption and FTIR techniques to perceive the interrelation between the physico-chemical and catalytic properties.
Deep eutectic solvents as H2-sources for Ru(II)-catalyzed transfer hydrogenation of carbonyl compounds under mild conditions
Cavallo, Marzia,Arnodo, Davide,Mannu, Alberto,Blangetti, Marco,Prandi, Cristina,Baratta, Walter,Baldino, Salvatore
supporting information, (2021/02/22)
The employment of easily affordable ruthenium(II)-complexes as pre-catalysts in the transfer hydrogenation of carbonyl compounds in deep eutectic media is described for the first time. The eutectic mixture tetrabutylammonium bromide/formic acid = 1/1 (TBABr/HCOOH = 1/1) acts both as reaction medium and hydrogen source. The addition of a base is required for the process to occur. An extensive optimization of the reaction conditions has been carried out, in terms of catalyst loading, type of complexes, H2-donors, reaction temperature and time. The combination of the dimeric complex [RuCl(p-cymene)-μ-Cl]2 (0.01–0.05 eq.) and the ligand dppf (1,1′-ferrocenediyl-bis(diphenylphosphine)ferrocene) in 1/1 molar ratio has proven to be a suitable catalytic system for the reduction of several and diverse aldehydes and ketones to their corresponding alcohols under mild conditions (40–60 °C) in air, showing from moderate to excellent tolerability towards different functional groups (halogen, cyano, nitro, phenol). The reduction of imine compounds to their corresponding amine derivatives was also studied. In addition, the comparison between the results obtained in TBABr/HCOOH and in organic solvents suggests a non-innocent effect of the DES medium during the process.