542-72-3Relevant academic research and scientific papers
Effect of the metal precursor on the properties of Ru/ZnO catalysts
Ramos-Fernández,Silvestre-Albero,Sepúlveda-Escribano,Rodríguez-Reinoso
, p. 221 - 227 (2010)
The effect of the ruthenium precursor (chlorinated or chlorine-free) on the properties and the catalytic behaviour of Ru/ZnO catalysts in the vapour phase hydrogenation of crotonaldehyde (2-butenal) has been studied. Two catalysts were prepared, using rut
Study of structure-performance relationships in Meerwein-Ponndorf-Verley reduction of crotonaldehyde on several magnesium and zirconium-based systems
Axpuac,Aramendía,Hidalgo-Carrillo,Marinas,Marinas,Montes-Jiménez,Urbano,Borau
, p. 183 - 190 (2012)
Several magnesia and zirconia systems were synthesized through the sol-gel process (calcination temperature in the 175-600°C range) and tested for liquid and gas-phase Meerwein-Ponndorf-Verley reduction of crotonaldehyde with 2-propanol. In the liquid pha
Hydrogenation of Cyclohexene in Aqueous Solvent Mixture Over a Sustainable Recyclable Catalyst Comprising Palladium and Monolacunary Silicotungstate Anchored to MCM-41
Patel, Anjali,Patel, Anish,Narkhede, Nilesh
, p. 423 - 429 (2019)
An efficient, highly stable, and ligand-free catalyst consisting of Pd and monolacunary silicotungstate anchored to MCM-41 was synthesized and characterized by various techniques. The synthesized catalyst was used for the hydrogenation reaction of cyclohe
The roles of metal-promoter interface on liquid phase selective hydrogenation of crotonaldehyde over Ir-MoOx/BN catalysts
Jia, Aiping,Lu, Jiqing,Luo, Mengfei,Tang, Cen,Wen, Yang,Xu, Yumeng,Zhou, Fangru
, (2021)
A series of MoOx-promoted Ir/BN catalysts were tested for liquid phase selective hydrogenation of crotonaldehyde. The MoOx-promotion could significantly improve the reactivity up to 5-fold. Such improvement was mainly due to the form
Mechanistic Insight to C-C Bond Formation and Predictive Models for Cascade Reactions among Alcohols on Ca- and Sr-Hydroxyapatites
Moteki, Takahiko,Flaherty, David W.
, p. 4170 - 4183 (2016)
Biomass-derived light alcohols (e.g., ethanol) may be upgraded via C-C bond formation to form larger alcohols and chemicals. The mechanism for coupling reactions among alcohols (i.e., Guerbet chemistry) is still debated, and the factors that determine the rates of subsequent, and inevitable, reactions among coupling products, and thus the product distributions, are not well understood. Here, the interpretation of the formation rates of products, in situ spectroscopy of surface intermediates, and evidence from isotope labeling experiments are combined to clarify the mechanism of the ethanol coupling over hydroxyapatite (HAP) catalysts. Initial C-C bonds are created by aldol condensation of acetaldehyde, derived in situ from ethanol, and involves a kinetically relevant deprotonation step to form the reactive enolate. In situ infrared spectra show that the coverage of ethanol-derived species far exceeds that of reactive aldehyde intermediates, which is consistent with C-C formation rates that inversely depend on ethanol pressure. Unsaturated aldehyde products are sequentially hydrogenated by the Meerwein-Ponndorf-Verley (MPV) reaction (i.e., C=O bond hydrogenation) and surface-mediated H-transfer (i.e., C=C bond hydrogenation). The MPV reaction simultaneously supplies reactive acetaldehyde needed for the coupling reaction by dehydrogenating ethanol. The rates of self- and cross-coupling reactions among C2-C4 alcohols are similar as are the values of the apparent activation enthalpies, which shows that self- and cross-coupling rates depend weakly on the structure of the reactants on HAP catalysts, with few exceptions. The carbon number distribution of the products from ethanol coupling closely matches predictions from an adapted step-growth model. Together, these findings show the mechanism for C-C bond formation between alcohol reactants on HAP catalysts and provide guidance for the production of higher carbon number species from alcohol coupling reactions.
Nanosized noble metals intercalated in clay as catalysts for selective hydrogenation
Dhanagopal, Manikandan,Duraiswami, Divakar,Valentine, Rupa A.,Ramalinga Viswanathan, Mangalaraja,Thiripuranthagan, Sivakumar
, p. 1200 - 1208 (2010)
The use of clay minerals in the synthesis of nanosized noble metal particles to give increased catalytic activity was investigated. Nanosized platinum and ruthenium catalysts intercalated in clay (montmorillonite/ hectorite) were synthesised and their catalytic activity was evaluated for the selective hydrogenation of three different α,β-unsaturated aldehydes, namely, crotonaldehyde, cinnamaldehyde, and citral, in a gas phase microreactor. The metal nano-sol was prepared by the chemical reduction of its precursor by the micellar technique in the presence of cetyl trimethyl ammonium bromide (CTAB), and the micelle stabilized metal particles were intercalated in the clay mineral by ion exchange. TEM micrographs of the catalyst particles showed that the metal particles were in the nanometre range. The average diameters of the particles were 1-25 nm. The effects of temperature, metal loading, and hydrogen flow rate on the catalytic activity and selectivity for α,β-unsaturated alcohol were studied. The results were correlated with the structural properties of the catalysts. The products formed in each reaction over the different catalysts showed that the catalysts were very active for hydrogenation, and the selectivity for the desired product, namely, α,β-unsaturated alcohol, was good. The metal catalysts intercalated in montmorillonite showed better selectivity than that in hectorite because of its higher acidity. Increased selectivity for α,β-unsaturated alcohol was observed with increased flow rate of hydrogen.
Non-Cryogenic, Ammonia-Free Reduction of Aryl Compounds
-
, (2022/03/31)
A method of reducing an aromatic ring or a cyclic, allylic ether in a compound includes preparing a reaction mixture including a compound including an aromatic moiety or a cyclic, allylic ether moiety, an alkali metal, and either ethylenediamine, diethylenetriamine, triethylenetetramine, or a combination thereof, in an ether solvent; and reacting the reaction mixture at from ?20° C. to 30° C. for a time sufficient to reduce a double bond in the aromatic moiety to a single bond or to reduce the cyclic, allylic ether moiety.
Total Synthesis of Mycinolide IV and Path-Scouting for Aldgamycin N
Herlé, Bart,Sp?th, Georg,Schreyer, Lucas,Fürstner, Alois
supporting information, p. 7893 - 7899 (2021/03/03)
Proof-of-concept is provided that a large estate of 16-membered macrolide antibiotics can be reached by a “unified” approach. The key building block was formed on scale by an asymmetric vinylogous Mukaiyama aldol reaction; its alkene terminus was then converted either into the corresponding methyl ketone by Wacker oxidation or into a chain-extended aldehyde by catalyst-controlled branch-selective asymmetric hydroformylation. These transformations ultimately opened access to two structurally distinct series of macrolide targets. Notable late-stage maneuvers comprise a rare example of a ruthenium-catalyzed redox isomerization of an 1,3-enyne-5-ol into a 1,3-diene-5-one derivative, as well as the elaboration of a tertiary propargylic alcohol into an acyloin by trans-hydrostannation/Chan-Lam-type coupling. Moreover, this case study illustrates the underutilized possibility of forging complex macrolactone rings by transesterification under essentially neutral conditions.
Selective production of 1,3-butadiene from 1,3-butanediol over Y2Zr2O7 catalyst
Matsuda, Asami,Matsumura, Yoshitaka,Sato, Satoshi,Yamada, Yasuhiro
, p. 1651 - 1658 (2021/07/21)
The vapor-phase dehydration of 1,3-butanediol (1,3-BDO) to produce 1,3-butadiene (BD) was evaluated over yttrium zirconate, which was prepared through a hydrothermal aging process. 1,3-BDO was initially dehydrated to three unsaturated alcohols, namely 3-buten-2-ol, 3-buten-1-ol, and 2-buten-1-ol, followed by the further dehydration to BD. The catalytic activity of yttrium zirconate was greatly dependent on the calcination temperature. Also, the reaction temperature was one of the important factors to produce BD efficiently. The selectivity to BD was increased with increasing reaction temperature up to 375°C, while coke formation resulted in catalyst deactivation together with by-product formation at higher temperatures. Yttrium zirconate catalyst calcined at 900°C showed a high BD yield of 95% at 375°C and 10 hr on stream.
Vapor-phase dehydration of 1,4-butanediol to 1,3-butadiene over Y2Zr2O7 catalyst
Matsuda, Asami,Matsumura, Yoshitaka,Sato, Satoshi,Yamada, Yasuhiro
, (2021/09/16)
Vapor-phase catalytic dehydration of 1,4-butanediol (1,4-BDO) was investigated over Y2O3-ZrO2 catalysts. In the dehydration, 1,3-butadiene (BD) together with 3-buten-1-ol (3B1OL), tetrahydrofuran, and propylene was produced depending on the reaction conditions. In the dehydration over Y2O3-ZrO2 catalysts with different Y contents at 325°C, Y2Zr2O7 with an equimolar ratio of Y/Zr showed high selectivity to 3B1OL, an intermediate to BD. In the dehydration at 360°C, a BD yield higher than 90% was achieved over the Y2Zr2O7 calcined at 700°C throughout 10 h. In the dehydration of 3B1OL over Y2Zr2O7, however, the catalytic activity affected by the calcination temperature is roughly proportional to the specific surface area of the sample. The highest activity of Y2Zr2O7 calcined at 700 °C for the BD formation from 1,4-BDO is explained by the trade-off relation in the activities for the first-step dehydration of 1,4-BDO to 3B1OL and for the second-step dehydration of 3B1OL to BD. The higher reactivity of 3B1OL than saturated alcohols such as 1-butanol and 2-butanol suggests that the C=C double bond of 3B1OL induces an attractive interaction to anchor the catalyst surface and promotes the dehydration. A probable mechanism for the one-step dehydration of 1,4-BDO to BD was discussed.
