71-23-8Relevant articles and documents
Hydrogenation catalysts based on platinum- and palladium-containing nanodiamonds
Magdalinova,Kalmykov,Klyuev
, p. 33 - 39 (2014)
Platinum and palladium nanoparticles of 4-5 nm size applied at nanodiamonds have been shown to efficiently catalyze liquid-phase hydrogenation of different organic compounds (nitrocompounds, azomethines, and unsaturated hydrocarbons and alcohols) under mild conditions (T = 318 K, hydrogen pressure of 0.1 MPa, solution in ethanol). Using of palladium on nanodiamond containing 3 wt % of metal has been most efficient.
Preparation of highly active heterogeneous Au@Pd bimetallic catalyst using plant tannin grafted collagen fiber as the matrix
Ma, Jun,Huang, Xin,Liao, Xuepin,Shi, Bi
, p. 8 - 16 (2013)
Au@Pd bimetallic nanoparticles (NPs) catalysts were synthesized by a seeding growth method using bayberry tannin grafted collagen fiber (BT-CF) as the matrix. In this method, Au3+ was first reductively adsorbed onto BT-CF to form Au NPs, and then they serve as the seeds for the over growth of Pd shell. The morphology of BT-CF-Au@Pd catalyst was observed by TEM and SEM, and the core-shell structure of the Au@Pd was confirmed by EDS and XRD. It was found that the as-prepared BT-CF-Au9@Pd3 catalyst showed excellent synergy effect in liquid-phase hydrogenation of cyclohexene, whose reaction time was three times faster than that catalyzed by BT-CF-Pd catalyst under the same conditions. Meanwhile, the BT-CF-Au9@Pd3 catalyst could be re-used four times without significant loss of activity. In the fourth run, the substrate conversion was still as high as 92.70%, much better than that by using commercial Pd/C catalyst (42.60%). Additionally, BT-CF-Au9@Pd3 catalyst exhibited high hydrogenation activity to various alkenes and nitro-compounds. For example, the TOF of allyl alcohol, styrene and nitrobenzene hydrogenations reached 10,980, 14,732 and 1379 mol mol-1 h-1, respectively.
Pd nanoparticles immobilized on boehmite by using tannic acid as structure-directing agent and stabilizer: A high performance catalyst for hydrogenation of olefins
Liu, Jing,Liao, Xuepin,Shi, Bi
, p. 249 - 258 (2014)
Boehmite-supported Pd nanoparticles (Pd-TA-boehmite) were successfully synthesized by a hydrothermal method using tannic acid as the structure-directing agent as well as stabilizer. The physicochemical properties of the Pd-TA-boehmite catalyst were well characterized by XPS, XRD, N 2 adsorption/desorption, and TEM analyses. Catalytic hydrogenation of olefins was used as the probe reaction to evaluate the activity of the Pd-TA-boehmite catalyst. For comparison, the Pd-boehmite catalyst prepared without tannic acid was also employed for olefin hydrogenation. For all the investigated substrates, the Pd-TA-boehmite catalyst exhibited superior catalytic performance than the Pd-boehmite catalyst. For the example of hydrogenation of allyl alcohol, the initial hydrogenation rate and selectivity of the Pd-TA-boehmite catalyst were 23,520 mol/mol h and 99 %, respectively, while those of the Pd-boehmite catalyst were only 14,186 mol/mol h and 93 %, respectively. Additionally, the hydrogenation rate of the Pd-TA-boehmite catalyst could still reach 20,791 mol/mol h at the 7th cycle, which was much higher than that of the Pd-boehmite catalyst (5,250 mol/mol h) at the 4th cycle, thus showing an improved reusability.
Solvent Effects in the Homogeneous Catalytic Reduction of Propionaldehyde with Aluminium Isopropoxide Catalyst: New Insights from PFG NMR and NMR Relaxation Studies
Muhammad, Atika,Di Carmine, Graziano,Forster, Luke,D'Agostino, Carmine
, p. 1101 - 1106 (2020)
Solvent effects in homogeneous catalysis are known to affect catalytic activity. Whilst these effects are often described using qualitative features, such as Kamlet-Taft parameters, experimental tools able to quantify and reveal in more depth such effects have remained unexplored. In this work, PFG NMR diffusion and T1 relaxation measurements have been carried out to probe solvent effects in the homogeneous catalytic reduction of propionaldehyde to 1-propanol in the presence of aluminium isopropoxide catalyst. Using data on diffusion coefficients it was possible to estimate trends in aggregation of different solvents. The results show that solvents with a high hydrogen-bond accepting ability, such as ethers, tend to form larger aggregates, which slow down the molecular dynamics of aldehyde molecules, as also suggested by T1 measurements, and preventing their access to the catalytic sites, which results in the observed decrease of catalytic activity. Conversely, weakly interacting solvents, such as alkanes, do not lead to the formation of such aggregates, hence allowing easy access of the aldehyde molecules to the catalytic sites, resulting in higher catalytic activity. The work reported here is a clear example on how combining traditional catalyst screening in homogeneous catalysis with NMR diffusion and relaxation time measurements can lead to new physico-chemical insights into such systems by providing data able to quantify aggregation phenomena and molecular dynamics.
Palladium-containing nanodiamonds in hydrogenation and hydroamination
Magdalinova,Kalmykov,Klyuev
, p. 299 - 304 (2012)
Palladium catalysts in the form of Pd nanoparticles supported on nanodiamonds have been studied in the hydrogenation of nitrobenzene, allyl alcohol, and cyclohexene and in the hydrogenating amination of propanal with 4-aminobenzoic acid. The ratio of two valence states of palladium, i.e., Pd 2+ and Pd0, in the catalysts has been determined by XPS. The dependence of hydrogenation reaction rate on electron density at the reaction site of nitrobenzene, allyl alcohol, cyclohexene, and 4-(propylideneamino)benzoic acid molecules has been studied using quantum chemical calculations (HF/6-31G, PCM). Pleiades Publishing, Ltd., 2012.
Sulphonated "click" dendrimer-stabilized palladium nanoparticles as highly efficient catalysts for olefin hydrogenation and Suzuki coupling reactions under ambient conditions in aqueous media
Ornelas, Catia,Ruiz, Jaime,Salmon, Lionel,Astruc, Didier
, p. 837 - 845 (2008)
Water-soluble 1,2,3-triazolyl dendrimers were synthesized by "click chemistry" and used to stabilize palladium nanoparticles (PdNPs). These new "click" dendrimer-stabilized nanoparticles (DSN) are highly stable to air and moisture and are catalytically active for olefin hydrogenation and Suzuki coupling reaction, in aqueous media, under ambient conditions using a low amount of palladium (0.01 mol% Pd). Kinetic studies show high catalytic efficiency and high stability for the new "click" DSN in both reactions. The complexation of potassium tetrachloropalladate (K 2PdCl4) to the triazole ligands present in the dendritic structures was monitored by UV/vis and, after reduction, the nanoparticles were characterized by transmission electron microscopy (TEM).
Pt-And Pd-containing nanodiamonds in hydrogenation and hydroamination reactions1
Magdalinova,Klyuev,Vershinin,Efimov
, p. 482 - 485 (2012)
The catalytic activity of platinum-And palladium-containing nanodiamonds has been investi-gated in liquid-phase nitrobenzene, allyl alcohol, and cyclohexene hydrogenation and propanal hydroami-nation with 4-Aminobenzoic acid as model reactions. The catalysts suggested are significantly more active than commercial Pd/C. The catalysts with a low metal weight content are the most effective in liquid phase catalytic hydrogenation. Pleiades Publishing, Ltd., 2012.
Inverse Bimetallic RuSn Catalyst for Selective Carboxylic Acid Reduction
Vorotnikov, Vassili,Eaton, Todd R.,Settle, Amy E.,Orton, Kellene,Wegener, Evan C.,Yang, Ce,Miller, Jeffrey T.,Beckham, Gregg T.,Vardon, Derek R.
, p. 11350 - 11359 (2019)
Inverse bimetallic catalysts (IBCs), synthesized by sequential deposition of noble and oxophilic metals, offer potential reactivity enhancements to various reactions, including the reduction of carboxylic acids for renewable fuels and chemicals. Here, we demonstrate that an IBC comprising RuSn exhibits high selectivity for propionic acid reduction to 1-propanol, while Ru alone results in cracking. On RuSn, X-ray absorption spectroscopy identified Ru0 nanoparticles with a near-surface bimetallic Ru0Sn0 alloy and small SnOx domains. Corresponding model surfaces were examined with density functional theory to elucidate the observed selectivity difference. Only selective hydrogenation is predicted to be favorable on SnOx/Ru, with the SnOx clusters facilitating C-OH scission and Ru enabling hydrogen activation. Intrinsic barriers along nonselective pathways suggest that the RuSn alloy and SnOx resist cracking. SnOx/Ru hydrogenation activity was supported experimentally by inhibiting hydrogenation with phenylphosphonic acid, differentiating the system from fully alloyed RuSn metallic nanoparticles. Overall, this work demonstrates a plausible mechanism for selective reduction of carboxylic acids and proposes a roadmap for rational design of IBCs.
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Edson
, p. 1855 (1936)
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Size-selective hydrogenation of olefins by Dendrimer-encapsulated palladium nanoparticles
Niu,Yeung,Crooks
, p. 6840 - 6846 (2001)
Nearly monodisperse (1.7 ± 0.2 nm) palladium nanoparticles were prepared within the interiors of three different generations of hydroxyl-terminated poly(amidoamine) (PAMAM) dendrimers. These dendrimer-encapsulated catalysts (DECs) were used to hydrogenate allyl alcohol and four α-substituted derivatives in a 4:1 methanol/water mixture. The results indicate that steric crowding on the dendrimer periphery, which increases with dendrimer generation, can act as an adjustable-mesh nanofilter. That is, by controlling the packing density on the dendrimer periphery, it is possible to control access of substrates to the encapsulated catalytic nanoparticle. In general, higher-generation DECs or larger substrates resulted in lower turnover frequencies (although some interesting exceptions were noted). Although the main products of the olefin hydrogenation reactions were the corresponding alkanes, ketones were also obtained when monosubstituted α-olefins were used as substrates. NMR spectroscopy was used to measure the size selectivity of DECs for the competitive hydrogenation of allyl alcohol and 3-methyl-1-penten-3-ol. The effect on catalytic rate as a function of nanoparticle size is also briefly discussed.
HOMOGENEOUS HYDROGENATION OF ALDEHYDES TO ALCOHOLS WITH RUTHENIUM COMPLEX CATALYSTS
Sanchez-Delgado, R.A.,Andriollo, A.,Ochoa, O.L. De,Suarez, T.,Valencia, N.
, p. 77 - 83 (1981)
A number of ruthenium complexes catalyse the reduction of aldehydes to their corresponding alcohols in toluene solution under mild reaction conditions.The most convenient catalyst precursor is hydridochlorocarbonyltris(triphenylphosphine)ruthenium(II).Turnover numbers up to 32 000 have been achieved with this catalyst.The rate of hydrogenation is first order with respect to the substrate concentration, the catalyst concentration and the hydrogen pressure, and is also affected by acid and basic additives.
Nanoconfinement Engineering over Hollow Multi-Shell Structured Copper towards Efficient Electrocatalytical C?C coupling
Li, Jiawei,Liu, Chunxiao,Xia, Chuan,Xue, Weiqing,Zeng, Jie,Zhang, Menglu,Zheng, Tingting
supporting information, (2021/12/06)
Nanoconfinement provides a promising solution to promote electrocatalytic C?C coupling, by dramatically altering the diffusion kinetics to ensure a high local concentration of C1 intermediates for carbon dimerization. Herein, under the guidance of finite-element method simulations results, a series of Cu2O hollow multi-shell structures (HoMSs) with tunable shell numbers were synthesized via Ostwald ripening. When applied in CO2 electroreduction (CO2RR), the in situ formed Cu HoMSs showed a positive correlation between shell numbers and selectivity for C2+ products, reaching a maximum C2+ Faradaic efficiency of 77.0±0.3 % at a conversion rate of 513.7±0.7 mA cm?2 in a neutral electrolyte. Mechanistic studies clarified the confinement effect of HoMSs that superposition of Cu shells leads to a higher coverage of localized CO adsorbate inside the cavity for enhanced dimerization. This work provides valuable insights for the delicate design of efficient C?C coupling catalysts.
One-pot reduction-hydrophobization of heterogenized platinum with 1,1,3,3-tetramethyldisiloxane
Baltag, Laurentiu,Cazacu, Maria,Damoc, Madalin,Dinu, Maria Valentina,Ionita, Gheorghe,Macsim, Ana-Maria,Nicolescu, Alina,Stoica, Alexandru-Constantin
, (2021/11/09)
An original approach for the design of hydrophobized heterogeneous platinum-based catalytic systems is reported here. Heterogenization was performed by depositing the platinum precursor (H2PtCl6) on macroporous styrene-divinylbenzene (SDVB) beads with a high surface area, -330 m2?g?1, as determined by N2 sorption data, followed by treating with 1,1,3,3-tetramethyldisiloxane (TMDS) as Pt(IV) reducing agent without the need of special conditions. Simultaneously, the coupling by Si-O-Si bonds of the TMDS oxidation or hydrolysis intermediates endowed the SDVB-Pt systems with an enhanced hydrophobicity (up to 10 times higher than that of SDVB support). In addition, to obtain an optimum catalytic system, which stabilize the supported platinium against leaching, several mixtures of TMDS with other methylsiloxane precursors, namely, methyltrimethoxysilane (MTMS), (Formula presented.)-bis(trimethylsiloxy)poly(dimethylsiloxane-H-methylsiloxane) (PDMHS), and (Formula presented.)-bis(trimethylsiloxy)poly(dimethylsiloxane-co-vinylmethylsiloxane) (PDMVS), have been systematically investigated. The reduction of platinum, visible by an instant change in the color from yellow to black, was confirmed by X-ray photoelectron spectroscopy analysis, while its total content in the samples was determined quantitatively by atomic absorption spectroscopy. The obtained systems have been preliminarily assessed for catalytic activity in the hydrosilylation of 1,3-bis(vinyl)tetramethyldisiloxane and allyl alcohol with TMDS, and 1-hexene with trimethoxysilane, as model reactions. The results indicate the high suitability of these systems as catalysts for the selective anti-Markovnikov hydrosilylation of alkenes, as well as for the very fast oxidation-condensation homocoupling of H-silanes in presence of a green oxidation agent (air), under mild conditions, with the release of hydrogen and its in situ addition to the double bond.
METHOD FOR PRODUCING BIO ALCOHOL FROM INTERMEDIATE PRODUCTS OF ANAEROBIC DIGESTION TANK
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Paragraph 0057-0060; 0063; 0065-0066; 0068-0069; 0071, (2021/05/25)
The present invention relates to a method for producing a bio-alcohol by reacting a mixture of volatile fatty acid with methanol in 2 through 11 in a reactor in the presence of a 280 °C-membered alkaline earth metal catalyst or 400 °C transition metal catalyst formed based on a support.