6117-80-2Relevant academic research and scientific papers
One-step synthesis of Pt@ZIF-8 catalyst for the selective hydrogenation of 1,4-butynediol to 1,4-butenediol
Li, Chuang,Zhang, Mingming,Di, Xin,Yin, Dongdong,Li, Wenzhen,Liang, Changhai
, p. 1555 - 1561 (2016)
A catalyst consisting of platinum nanoparticles on a ZIF-8 support (Pt@ZIF-8) was synthesized in a straightforward one-step procedure, by adding a nanostructured platinum sol during the formation of ZIF-8 at room temperature. Pt@ZIF-8 was highly porous an
PVP-Pd@ZIF-8 as highly efficient and stable catalysts for selective hydrogenation of 1,4-butynediol
Zhang, Mingming,Yang, Yuebin,Li, Chuang,Liu, Qian,Williams, Christopher T.,Liang, Changhai
, p. 329 - 332 (2014)
Cubic Pd nanoparticles were rapidly encapsulated in ZIF-8 through a PVP-assisted synthetic method at room temperature. The obtained PVP-Pd@ZIF-8 exhibited high activity and stability for hydrogenation of 1,4-butynediol, with excellent selectivity to 1,4-b
An excellent nickel boride catalyst for the cis-selective semihydrogenation of acetylenes
Choi, Jaesung,Yoon, Nung Min
, p. 1057 - 1060 (1996)
Internal alkynes were hydrogenated quantitatively to the corresponding cis-alkenes over nickel boride (Ni2B), prepared on borohydride exchange resin (BER) in methanol under hydrogen atmosphere. Further hydrogenation was very slow under the reaction conditions, and pure cis-alkenes were conveniently isolated in excellent yields. Hydroxy and ester functional groups did not interfere with the semihydrogenation.
Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts
?zer, Halenur,Arslan, Dilan,?ztürk, Bengi ?zgün
, p. 5992 - 6000 (2021/04/12)
In this study,in situformed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the β-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain γ-butyrolactone and long-chain ester derivatives in quantitative yields.
Highly selective semi-hydrogenation of alkynes with a Pd nanocatalyst modified with sulfide-based solid-phase ligands
Huang, Lingqi,Hu, Kecheng,Ye, Ganggang,Ye, Zhibin
, (2021/03/30)
Soluble small molecular/polymeric ligands are often used in Pd-catalyzed semi-hydrogenation of alkynes as an efficient strategy to improve the selectivity of targeted alkene products. The use of soluble ligands requires their thorough removal from the reaction products, which adds significant extra costs. In the paper, commercially available, inexpensive, metallic sulfide-based solid-phase ligands (SPL8-4 and SPL8-6) are demonstrated as simple yet high-performance insoluble ligands for a heterogeneous Pd nanocatalyst (Pd@CaCO3) toward the semi-hydrogenation of alkynes. Based on the reactions with a range of terminal and internal alkyne substrates, the use of the solid-phase ligands has been shown to markedly enhance the selectivity of the desired alkene products by efficiently suppressing over-hydrogenation and isomerization side reactions, even during the long extension of the reactions following full substrate conversion. A proper increase in the dosage or a reduction in the average size of the solid-phase ligands enhances such effects. With their insoluble nature, the solid-phase ligands have the distinct advantage in their simple, convenient recycling and reuse while without contaminating the products. A ten-cycle reusability test with the SPL8-4/Pd@CaCO3 catalyst system confirms its well-maintained activity and selectivity over repeated uses. A mechanistic study with x-ray photoelectron spectroscopy indicates that the solid-phase ligands have electronic interactions with Pd in the supported catalyst, contributing to inhibit the binding and further reaction of the alkene products. This is the first demonstration of solid-phase ligands for highly selective semi-hydrogenation of alkynes, which show strong promise for commercial applications.
Parahydrogen-Induced Polarization Relayed via Proton Exchange
Them, Kolja,Ellermann, Frowin,Pravdivtsev, Andrey N.,Salnikov, Oleg G.,Skovpin, Ivan V.,Koptyug, Igor V.,Herges, Rainer,H?vener, Jan-Bernd
supporting information, p. 13694 - 13700 (2021/09/07)
The hyperpolarization of nuclear spins is a game-changing technology that enables hitherto inaccessible applications for magnetic resonance in chemistry and biomedicine. Despite significant advances and discoveries in the past, however, the quest to establish efficient and effective hyperpolarization methods continues. Here, we describe a new method that combines the advantages of direct parahydrogenation, high polarization (P), fast reaction, and low cost with the broad applicability of polarization transfer via proton exchange. We identified the system propargyl alcohol + pH2 → allyl alcohol to yield 1H polarization in excess of P ≈ 13% by using only 50% enriched pH2 at a pressure of ≈1 bar. The polarization was then successfully relayed via proton exchange from allyl alcohol to various target molecules. The polarizations of water and alcohols (as target molecules) approached P ≈ 1% even at high molar concentrations of 100 mM. Lactate, glucose, and pyruvic acid were also polarized, but to a lesser extent. Several potential improvements of the methodology are discussed. Thus, the parahydrogen-induced hyperpolarization relayed via proton exchange (PHIP-X) is a promising approach to polarize numerous molecules which participate in proton exchange and support new applications for magnetic resonance.
Continuous Flow Z-Stereoselective Olefin Metathesis: Development and Applications in the Synthesis of Pheromones and Macrocyclic Odorant Molecules**
Browne, Duncan L.,Colombel-Rouen, Sophie,Crévisy, Christophe,Curbet, Idriss,Mauduit, Marc,McBride, Tom,Morvan, Jennifer,Roisnel, Thierry
supporting information, p. 19685 - 19690 (2021/08/06)
The first continuous flow Z-selective olefin metathesis process is reported. Key to realizing this process was the adequate choice of stereoselective catalysts combined with the design of an appropriate continuous reactor setup. The designed continuous process permits various self-, cross- and macro-ring-closing-metathesis reactions, delivering products in high selectivity and short residence times. This technique is exemplified by direct application to the preparation of a range of pheromones and macrocyclic odorant molecules and culminates in a telescoped Z-selective cross-metathesis/ Dieckmann cyclisation sequence to access (Z)-Civetone, incorporating a serial array of continually stirred tank reactors.
Fourth subgroup metal complex with rigid annular bridging structure and application of fourth subgroup metal complex
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Paragraph 0058; 0061; 0066, (2021/06/23)
The invention belongs to the technical field of olefin polymerization catalysts, and particularly relates to a fourth subgroup metal complex with a rigid annular bridging structure and an application of the fourth subgroup metal complex. The fourth subgroup metal complex provided by the invention has a structure represented by a formula (A) or a formula (B), X is halogen or alkyl; and M is titanium, zirconium or hafnium. On the basis of a non-metallocene catalyst, a bridging structure in catalyst molecules is improved and upgraded, and a brand-new metal complex with excellent catalytic performance and good high-temperature tolerance is designed; when the fourth subgroup metal complex is used as a main catalyst to catalyze olefin polymerization reaction, under the activation action of a small amount of mixed cocatalyst, the fourth subgroup metal complex can efficiently catalyze the copolymerization reaction of ethylene and alpha-olefin to obtain polyolefin with high molecular weight and high comonomer insertion rate.
Preparation method of N-(4-methylpyridine-3-yl) methyl carbamate
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Paragraph 0020; 0022; 0025; 0030; 0032; 0035; 0040; 0042, (2021/06/02)
The invention relates to the technical field of preparation methods of N-(4-methylpyridine-3-yl) methyl carbamate, and discloses preparation of potassium tert-butoxide and preparation of the potassium tert-butoxide by using potassium methoxide. According to the preparation method of the N-(4-methylpyridine-3-yl) methyl carbamate, a user uses the potassium methoxide to prepare the potassium tert-butoxide, so that the content of the potassium tert-butoxide is higher, the potassium tert-butoxide and the potassium methoxide are very similar in properties and functions, so that the cost is saved, the method for extracting a THT solvent by using 1, 4-dichlorobutene as a raw material is simple, and the method has the advantages that the use amount of the catalyst is small, the condition is mild, the extraction purity is high, so that the cost is reduced again; and the N-(4-methylpyridine-3-yl) methyl carbamate is obtained by catalyzing two high-purity raw materials through the catalyst carbonic acid diester and stirring, so that the preparation efficiency is improved, the purity of the prepared N-(4-methylpyridine-3-yl) methyl carbamate is improved, the over-high preparation cost of the N-(4-methylpyridine-3-yl) methyl carbamate is avoided, and the use of the user is facilitated.
Olefin reaction in the catalyst and the olefin production
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Paragraph 0145-0146; 0149, (2020/10/31)
PROBLEM TO BE SOLVED: To provide a catalyst for obtaining an olefin in high selectivity with a vicinal diol as a raw material.SOLUTION: A catalyst for olefination reaction for use in a reaction to produce an olefin by a reaction of a polyol, having two adjacent carbon atoms each having a hydroxy group, with hydrogen comprises: a carrier; at least one oxide selected from the group consisting of oxides of the group 6 elements and oxides of the group 7 elements supported on the carrier; and at least one metal selected from the group consisting of silver, iridium, and gold supported on the carrier.SELECTED DRAWING: None
