2437-25-4Relevant academic research and scientific papers
Fatty acid methyl esters into nitriles: Acid-base properties for enhanced catalysts
Mekki-Berrada,Bennici,Gillet,Couturier,Dubois,Auroux
, p. 30 - 37 (2013)
Fatty nitriles have lately become of interest in the frame of biofuels or for the valorization of the oil part of biomass as fine chemicals such as polymers. The production of long-chain fatty nitriles by direct reaction of esters with ammonia has however not been academically extensively studied, although several catalysts were developed and published in patents. Acid-base features are implicitly considered as leading the catalysis of this reaction, but no direct correlation was investigated with any nature or number of acidic or basic sites. The present study aims at understanding which sites are responsible of this reaction and thus how to design better catalysts. Strong acidity correlates at 300 C for ester conversion and nitrile yield, suggesting a common nature of the reaction among all kinds of catalysts. An upper strength limit, over which undesirable side-products appear, was evaluated, and the factors influencing the production of N-methyl amide were analyzed.
A Molecular Iron-Based System for Divergent Bond Activation: Controlling the Reactivity of Aldehydes
Chatterjee, Basujit,Jena, Soumyashree,Chugh, Vishal,Weyhermüller, Thomas,Werlé, Christophe
, p. 7176 - 7185 (2021/06/30)
The direct synthesis of amides and nitriles from readily available aldehyde precursors provides access to functional groups of major synthetic utility. To date, most reliable catalytic methods have typically been optimized to supply one product exclusively. Herein, we describe an approach centered on an operationally simple iron-based system that, depending on the reaction conditions, selectively addresses either the C=O or C-H bond of aldehydes. This way, two divergent reaction pathways can be opened to furnish both products in high yields and selectivities under mild reaction conditions. The catalyst system takes advantage of iron's dual reactivity capable of acting as (1) a Lewis acid and (2) a nitrene transfer platform to govern the aldehyde building block. The present transformation offers a rare control over the selectivity on the basis of the iron system's ionic nature. This approach expands the repertoire of protocols for amide and nitrile synthesis and shows that fine adjustments of the catalyst system's molecular environment can supply control over bond activation processes, thus providing easy access to various products from primary building blocks.
Facile dehydration of primary amides to nitriles catalyzed by lead salts: The anionic ligand matters
Ruan, Shixiang,Ruan, Jiancheng,Chen, Xinzhi,Zhou, Shaodong
, (2020/12/09)
The synthesis of nitrile under mild conditions was achieved via dehydration of primary amide using lead salts as catalyst. The reaction processes were intensified by not only adding surfactant but also continuously removing the only by-product, water from the system. Both aliphatic and aromatic nitriles can be prepared in this manner with moderate to excellent yields. The reaction mechanisms were obtained with high-level quantum chemical calculations, and the crucial role the anionic ligand plays in the transformations were revealed.
Iodine Promoted Conversion of Esters to Nitriles and Ketones under Metal-Free Conditions
Xiao, Jing,Guo, Fengzhe,Li, Yinfeng,Li, Fangshao,Li, Qiang,Tang, Zi-Long
, p. 2028 - 2035 (2021/02/03)
We report a novel strategy to prepare valuable nitriles and ketones through the conversion of esters under metal-free conditions. By using the I2/PCl3 system, various substrates including aliphatic and aromatic esters could react with acetonitrile and arenes to afford the desired products in good to excellent yields. This method is compatible with a number of functional groups and provides a simple and practical approach for the synthesis of nitrile compounds and aryl ketones.
Method for catalyzing receptor-free dehydrogenation of primary amine to generate nitrile by Ru coordination compound
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Paragraph 0034-0039; 0249-0254, (2020/09/16)
The invention discloses a method for catalyzing receptor-free dehydrogenation of primary amine to generate nitrile by a Ru coordination compound. The method comprises: adding a Ru coordination compound, an alkali, a primary amine and an organic solvent into a reaction test tube according to a mol ratio of 1:100:(100-500):1000-3000, and carrying out a stirring reaction under the condition of 80 to120 DEG C; and when gas chromatography monitors that the raw materials completely disappear, stopping the reaction, collecting the reaction solution, centrifuging the reaction solution, taking the supernatant, extracting with dichloromethane, merging the organic phases, drying, filtering, evaporating the organic solvent under reduced pressure to obtain a filtrate, and carrying out column chromatography purification on the filtrate to obtain the target product nitrile. According to the invention, the catalyst is good in activity, single in catalytic system, good in product selectivity, simple in subsequent treatment and good in system universality after the reaction is finished, has a good catalytic effect on various aryl, alkyl and heteroaryl substituted primary amines, and also has a gooddehydrogenation performance on secondary amines.
Method for continuous preparation of nitriles by amides (by machine translation)
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Paragraph 0033-0054; 0061-0066, (2020/12/15)
The method comprises the following steps: preparing a lead salt supported by a molecular sieve by a lead salt and a molecular sieve through an impregnation method; and filling a molecular sieve-loaded lead catalyst into a fixed bed reactor. The amide or amide solution is sent into a fixed bed reactor from the top of the fixed bed to be subjected to catalytic dehydration, and the obtained reaction product is led out from the bottom of the fixed bed. The reaction product is separated to obtain the crude product of the nitrile corresponding to the amide. A fixed bed continuous production process is adopted, the reaction process is simple, the production efficiency is high, the product post-treatment is simple, and industrial production is easy to realize. (by machine translation)
Synthesis, characterization, catalytic and biological application of half-sandwich ruthenium complexes bearing hemilabile (κ2-: C, S)-thioether-functionalised NHC ligands
Achard, Thierry,Bellemin-Laponnaz, Stéphane,Chen, Weiguang,Egly, Julien,Maisse-Francois, Aline,Poblador-Bahamonde, Amalia I.
supporting information, p. 3243 - 3252 (2020/03/19)
A series of cationic Ru(ii)(η6-p-cymene) complexes with thioether-functionalised N-heterocyclic carbene ligands have been prepared and fully characterized. Steric and electronic influence of the R thioether substituent on the coordination of the sulfur atom was investigated. The molecular structure of three of them has been determined by means of X-ray diffractrometry and confirmed the bidentate (κ2-C,S) coordination mode of the ligand. Interestingly, only a single diastereomer, as an enantiomeric couple, was observed in the solid state for complexes 1c, 1i and 1j. DFT calculations established a low energy inversion barrier between the two diastereomers through a sulfur pyramidal inversion pathway with R donating group while a dissociative/associative mechanism is more likely with R substituents that contain electron withdrawing group, thus suggesting that the only species observed by the 1H-NMR correspond to an average resonance position of a fluxional mixtures of isomers. All these complexes were found to catalyse the oxydant-free double dehydrogenation of primary amine into nitrile. Ru complex bearing NHC-functionalised S-tBu group was further investigated in a wide range of amines and was found more selective for alkyl amine substrates than for benzylamine derivatives. Finally, preliminary results of the biological effects on various human cancer cells of four selected Ru complexes are reported.
Acceptorless dehydrogenation of amines to nitriles catalyzed by N-heterocyclic carbene-nitrogen-phosphine chelated bimetallic ruthenium (II) complex
Chen, Hua,Fu, Haiyan,Ji, Li,Li, Ruixiang,Nie, Xufeng,Zheng, Yanling
, p. 378 - 385 (2020/10/02)
We have developed a clean, atom-economical and environmentally friendly route for acceptorless dehydrogenation of amines to nitriles by combining a new dual N-heterocyclic carbene-nitrogen-phosphine ligand R(CNP)2 (R = o-xylyl) with a ruthenium precursor [RuCl2(η6-C6H6)]2. In this system, the electronic and steric factors of amines had a negligible influence on the reaction and a broad range of functional groups were well tolerated. All of the investigated amines could be converted to nitriles in good yield of up to 99% with excellent selectivity. The unprecedented catalytic performance of this system is attributed to the synergistic effect of two ruthenium centers chelated by R(CNP)2 and a plausible reaction mechanism is proposed according to the active species found via in situ NMR and HRMS.
Dehydrogenation of Primary Alkyl Azides to Nitriles Catalyzed by Pincer Iridium/Ruthenium Complexes
Gan, Lan,Jia, Xiangqing,Fang, Huaquan,Liu, Guixia,Huang, Zheng
, p. 3661 - 3665 (2020/06/02)
Pincer metal complexes exhibit superior catalytic activity in the dehydrogenation of plain alkanes, but find limited application in the dehydrogenation of functionalized organic molecules. Starting from easily accessible primary alkyl azides, here we report an efficient dehydrogenation of azides to nitriles using pincer iridium or ruthenium complexes as the catalysts. This method offers a route to cyanide-free preparation of nitriles without carbon chain elongation and without the use of strong oxidants. Both benzyl and linear aliphatic azides can be dehydrogenated with tert-butylethylene as the hydrogen acceptor to afford nitriles in moderate to high yields. Various functional groups can be tolerated, and the H?C?C?H bond dehydrogenation does not occur for linear alkyl azide substrates. Furthermore, the pincer Ir catalytic system was found to catalyze the direct azide dehydrogenation without the use of a sacrificial hydrogen acceptor.
Tuning of active sites in M/TiO2 for photocatalytic cyanation of olefins with high regioselectivity
Bao, Jingxian,Huang, Min,Sun, Yuhan,Wu, Bo,Zhang, Shuyi,Zhong, Liangshu
, (2020/08/25)
The detailed structure of active sites plays an important role for the determination of catalytic performance. Herein, catalytic active sites of M/TiO2 for photocatalytic cyanation of olefins are tuned by delicate manipulation of the metal kinds, metal loading amount and pretreatment processes. It was found that the 0.1% Pt/P25 catalyst reduced at 300 °C possessed high metal dispersion and suitable oxygen defects on TiO2, and thus exhibited the best catalytic performance with high specific speed of time yield and high selectivity. A wide scope of olefin substrates could be converted to the corresponding nitriles with high atom efficiency and anti-Markovnikov regioselectivity under mild conditions for the optimized Pt/P25 catalyst. The reaction mechanism based on radical coupling of acetonitrile and olefins was also discussed. This approach offers an environmental-friendly platform for the selective activation of C-H bonds of acetonitrile and will bring potential applications for hydrofunctionalization of olefins.
