629-08-3Relevant academic research and scientific papers
Product selectivity controlled by manganese oxide crystals in catalytic ammoxidation
Hui, Yu,Luo, Qingsong,Qin, Yucai,Song, Lijuan,Wang, Hai,Wang, Liang,Xiao, Feng-Shou
, p. 2164 - 2172 (2021/09/20)
The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures. Here we report a controllable nitrile synthesis from alcohol ammoxidation, where the nitrile hydration side reaction could be efficiently prevented by changing the manganese oxide catalysts. α-Mn2O3 based catalysts are highly selective for nitrile synthesis, but MnO2-based catalysts including α, β, γ, and δ phases favour the amide production from tandem ammoxidation and hydration steps. Multiple structural, kinetic, and spectroscopic investigations reveal that water decomposition is hindered on α-Mn2O3, thus to switch off the nitrile hydration. In addition, the selectivity-control feature of manganese oxide catalysts is mainly related to their crystalline nature rather than oxide morphology, although the morphological issue is usually regarded as a crucial factor in many reactions.
Direct C(sp3)-H Cyanation Enabled by a Highly Active Decatungstate Photocatalyst
Kim, Kunsoon,Lee, Seulchan,Hong, Soon Hyeok
supporting information, p. 5501 - 5505 (2021/07/26)
A highly efficient, direct C(sp3)-H cyanation was developed under mild photocatalytic conditions. The method enabled the direct cyanation of various C(sp3)-H substrates with excellent functional group tolerance. Notably, complex natural products and bioactive compounds were efficiently cyanated.
An Efficient Synthesis of Nitriles from Aldoximes in the Presence of Trifluoromethanesulfonic Anhydride in Mild Conditions
Uludag, N.
, p. 1640 - 1645 (2020/10/22)
Abstract: A new and convenient protocol has been proposed for the transformation of aldoximes to nitriles using trifluoromethanesulfonic anhydride and triethylamine. The proposed method allows a range of aldoximes, including aromatic, heterocyclic, aliphatic, and cycloaliphatic aldoximes, to be converted to the corresponding nitriles in good to excellent yields.
One-pot synthesis of aldoximes from alkenes: Via Rh-catalysed hydroformylation in an aqueous solvent system
Gr?ger, H.,Guntermann, A.,Hinzmann, A.,Jolmes, T.,Panke, D.,Plass, C.,R?sler, J.,Seidensticker, T.,Terhorst, M.,Vogt, D.,Vorholt, A. J.
, p. 7974 - 7982 (2020/11/30)
Aldoxime synthesis directly starting from alkenes was successfully achieved through the combination of hydroformylation and subsequent condensation of the aldehyde intermediate with aqueous hydroxylamine in a one-pot process. The metal complex Rh(acac)(CO)2 and the water-soluble ligand sulfoxantphos were used as the catalyst system, providing high regioselectivities in the initial hydroformylation. A mixture of water and 1-butanol was used as an environmentally benign solvent system, ensuring sufficient contact of the aqueous catalyst phase and the organic substrate phase. The reaction conditions were systematically optimised by Design of Experiments (DoE) using 1-octene as a model substrate. A yield of 85% of the desired linear, terminal aldoxime ((E/Z)-nonanal oxime) at 95% regioselectivity was achieved. Other terminal alkenes were also converted successfully under the optimised conditions to the corresponding linear aldoximes, including renewable substrates. Differences of the reaction rate have been investigated by recording the gas consumption, whereby turnover frequencies (TOFs) >2000 h-1 were observed for 4-vinylcyclohexene and styrene, respectively. The high potential of aldoximes as platform intermediates was shown by their subsequent transformation into the corresponding linear nitriles using aldoxime dehydratases as biocatalysts. The overall reaction sequence thus allows for a straightforward synthesis of linear nitriles from alkenes with water being the only by-product, which formally represents an anti-Markovnikov hydrocyanation of readily available 1-alkenes.
Ruthenium(II)-Complex-Catalyzed Acceptorless Double Dehydrogenation of Primary Amines to Nitriles
Kannan, Muthukumar,Muthaiah, Senthilkumar
supporting information, p. 1073 - 1076 (2020/07/04)
Acceptorless dehydrogenative oxidation of primary amines into nitriles using an in situ complex derived from commercially available dichloro(1,5-cyclooctadiene) ruthenium(II) complex and simple hexamethylenetetramine has been demonstrated. The synthetic protocol is highly selective and yields the nitrile compounds in moderate to excellent yields and produces hydrogen as the sole byproduct.
Acceptorless dehydrogenation of amines and alcohols using simple ruthenium chloride
Barteja, Parul,Devi, Preeti,Kannan, Muthukumar,Muthaiah, Senthilkumar
, p. 1 - 11 (2020/04/17)
A highly efficient, economic and environmental friendly catalyst system has been developed for the dehydrogenation of alcohols and amines using simple RuCl3·nH2O and N-benzylhexamethylenetetramine. The in situ catalyst system efficiently oxidized the primary and secondary amines and secondary alcohols into nitrile, imine and ketone products, respectively in moderate to excellent yields. The developed catalyst system was also found to be efficient for the dehydrogenation of N-heterocyles. A detailed mechanism study revealed the first example of N-benzylhexamethylenetetramine (HMTA-Bz) being simultaneously acting as base, reducing agent and hydride source to generate the [Ru(II)(H)2] species as the active catalyst. The mechanism studies also revealed both the alcohol and amine oxidation involves dehydrogenative pathway with the evolution of hydrogen as the only by-product. The developed catalyst system also provides possible platform for the release of hydrogen from liquid organic hydrogen carriers (LOHCs).
Atomically Dispersed Ru on Manganese Oxide Catalyst Boosts Oxidative Cyanation
Gates, Bruce C.,Guan, Erjia,Meng, Xiangju,Wang, Chengtao,Wang, Hai,Wang, Liang,Wang, Sai,Xiao, Feng-Shou,Xu, Dongyang,Xu, Hua,Yang, Bo,Zhang, Jian
, p. 6299 - 6308 (2020/07/21)
There is a strong incentive for environmentally benign and sustainable production of organic nitriles to avoid the use of toxic cyanides. Here we report that manganese oxide nanorod-supported single-site Ru catalysts are active, selective, and stable for oxidative cyanation of various alcohols to give the corresponding nitriles with molecular oxygen and ammonia as the reactants. The very low amount of Ru (0.1 wt %) with atomic dispersion boosts the catalytic performance of manganese oxides. Experimental and theoretical results show how the Ru sites enhance the ammonia resistance of the catalyst, bolstering its performance in alcohol dehydrogenation and oxygen activation, the key steps in the oxidative cyanation. This investigation demonstrates the high efficiency of a single-site Ru catalyst for nitrile production.
Extending the Chemistry of Hexamethylenetetramine in Ruthenium-Catalyzed Amine Oxidation
Kannan, Muthukumar,Muthaiah, Senthilkumar
supporting information, p. 3560 - 3567 (2019/11/13)
A very efficient, highly atom economical, and environmentally benign oxidation of primary and secondary amines using an in situ catalyst system generated from commercially available ruthenium(II) benzene dichloride dimer and hexamethylenetetramine has been demonstrated. Mechanistic studies revealed that hexamethylenetetramine acted as a source of hydride to generate the active ruthenium hydride catalyst and amine oxidation involves a dehydrogenative pathway. In comparison to reported catalyst systems for the dehydrogenative oxidation of amines, this synthetic protocol makes use of a simple ruthenium precursor and a cheaper additive; it is very selective, leading to the exclusive formation of nitrile/imine compounds. Further, it releases hydrogen as the only side product, suggesting the potential application of the developed catalyst system in hydrogen storage.
A method of synthesizing fatty nitrile by the aliphatic aldehyde
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Paragraph 0027; 0028; 0047; 0048, (2019/05/28)
The invention relates to a method of synthesizing fatty nitrile by the aliphatic aldehyde. The method comprises the following steps: the aliphatic aldehyde, ionic liquid regenerating and ionic liquid in the reactor, to join the two toluene, stirring, of the reflux condensation, in the normal pressure, 90 - 120 °C reaction under 0.5 - 2 h, to obtain the product fatty nitrile; wherein said ionic liquid is 1 - sulfobutyl pyridine bisulphate ionic liquid; ion liquid hydroxylamine salt is 1 - sulfobutyl pyridine bisulphate ion liquid hydroxylamine salt. The invention in one reactor to achieve the fat [...] and fat aldoxime dehydration integrated two-step reaction, the process is simple, easy to operate; to ionic liquid as catalyst and a co-solvent, without the addition of metal salt catalyst and corrosive solvent, environment-friendly.
Identification of an Active NiCu Catalyst for Nitrile Synthesis from Alcohol
Wang, Yunzhu,Furukawa, Shinya,Yan, Ning
, p. 6681 - 6691 (2019/07/12)
Development of heterogeneous catalysts for alcohol transformation into nitriles under oxidant-free conditions is a challenge. Considering the C-H activation on α-carbon of primary alcohols is the rate-determining step, decreasing the activation energy of C-H activation is critical in order to enhance the catalytic activity. Several NiM/Al2O3 bimetallic catalysts were synthesized and scrutinized in catalytic transformation of 1-butanol to butyronitrile. Ni-Cu was identified as a suitable combination with the optimized Ni0.5Cu0.5/Al2O3 catalyst exhibiting 10 times higher turnover frequency than Ni/Al2O3 catalyst. X-ray absorption spectroscopy (XAS) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) revealed that the NiCu particles in the catalyst exist in the form of homogeneous alloys with an average size of 8.3 nm, providing an experimental foundation to build up a catalyst model for further density functional theory (DFT) calculations. Calculations were done over a series of NiM catalysts, and the experimentally observed activity trend could be rationalized by the Br?nsted-Evans-Polanyi (BEP) principle, i.e., catalysts that afford reduced reaction energy also feature lower activation barriers. The calculated activation energy (Ea) for C-H activation with coadsorbed NH3 dropped from 63.4 kJ/mol on pure Ni catalyst to 49.9 kJ/mol on the most active NiCu-2 site in NiCu bimetallic catalyst, in good agreement with the experimentally measured activation energy values. The Ni0.5Cu0.5/Al2O3 catalyst was further employed to convert 11 primary alcohols into nitriles with high to near-quantitative yields, at a Ni loading 10 times less than that of the conventional Ni/Al2O3 catalyst.
