142-84-7Relevant academic research and scientific papers
Semiconductor Photocatalysis.ZnS-Catalyzed Photoreduction of Aldehydes and Related Derivatives: Two-Electron-Transfer Reduction and Relationship with Spectroscopic Properties
Yanagida, Shozo,Ishimaru, Yoshiteru,Miyake, Yoshio,Shiragami, Tsutomu,Pac, Chyongjin,et al.
, p. 2576 - 2582 (1989)
Photocatalytic activity and spectroscopic properties of ZnS suspensions for the two-electron reduction of aldehydes or related compounds in aqueous medium are described.The ZnS suspension (ZnS-0) prepared by cooling from aqueous ZnSO4 and Na2S solutions catalyzes photoredox reactions of acetaldehyde, giving ethanol without much H2 evolution as a two-electron-reduction product, and acetic acid, biacetyl, and acetoin as oxidation products.When the ZnS-0 suspension is refluxed (giving ZnS-100) or dried to powder, the resulting ZnS shows an increased activity for H2 evolution but a decreased activity for the two-electron reduction.The two-electron photoreduction is ascribed to the sequential transfer of active electrons in the conduction band of defect-free aggregates of ZnS microcrystallites (quantized ZnS).This mechanism is supported by product analysis, energetics at ZnS interfaces, the sharp and blue-shifted onset of absorption and excitation spectra, and the long-life band gap emission of the active ZnS-0 suspension.UV, emission, and ESR spectra, as well as the enhancement of the particle size and crystallinity, suggest that the activity change observed after heating or drying to powder is due to the formation of surface states which may trap active electrons.This interpretation is also supported by the generated activity of ZnS-100 for the H2 photoevolution under >350-nm irradiation.ZnS photocatalysis under >350-nm irradiation and relationship with spectroscopic properties are also discussed.
Regioselectivity and stereoelectronic effects in the reactions of the dinitroaniline herbicides trifluralin and benefin with nucleophiles
Annandale, Michael T.,VanLoon, Gary W.,Buncel, Erwin
, p. 873 - 883 (1998)
The reactions of two members of the dinitroaniline class of herbicides, N,N-di-n-propyl-2,6-dinitro-4-(trifluoromethyl)aniline (trifluralin; 1) and N-ethyl-N-n-butyl-2,6-dinitro-4-(trifluoromethyl)aniline (benefin; 2), along with their analogue, N-phenyl-2,6-dinitro-4-(trifluoromethyl)aniline (3), with the nucleophiles, OD- and SO32-, have been investigated using 400 MHz 1H NMR spectroscopy. The reactions of both 1 and 2 with OD- result in formation of Meisenheimer anionic σ-complexes according to a K3T1 (kinetic preference for formation of the C-3 adduct with thermodynamic preference for formation of the C-1 adduct) reaction sequence while the reaction of 3 with OD- and that of 1 with SO32- follow a K3T3 (kinetic and thermodynamic preference for formation of the C-3 adduct) sequence. There was no observation of the C-1 adducts of 1 and 2 with OD-, but the products of S(N)Ar displacement at C-1 were observed as the final thermodynamic products. Geometry optimization calculations support our hypothesis of n → σ* stabilization of the C-1 adduct leading to S(N)Ar displacement. In the reaction of 3 with OD-, initial N-deprotonation to form the anion, 3a, is followed by σ-complex formation. The final thermodynamic product observed in this system is 3,5-dinitro-4-(N-phenylamino)benzoic acid formed through hydrolysis of the trifluoromethyl group on the anion, 3a. Aryl H-D exchange has been found for the systems of 1 and 2 with OD-, but not for the SO32- system and neither for the reaction of 3 with OD-. Since dimethylpicramide showed significantly slower H-D exchange under identical conditions, it is argued that this discrepancy has as origin the ability of the amino N lone electron pair to interact with the π-system of the ring. With both 1 and 2 the larger size of the amino alkyl chains prevent the amino N lone pair from aligning with the π-system of the ring, thus hindering electron density donation to the electron-deficient ring carbons.
A New and Convenient Process for Separation of Carbon Monoxide
Sonoda, Noboru,Miyoshi, Noritaka,Tsunoi, Shinji,Ogawa, Akiya,Kambe, Nobuaki
, p. 1873 - 1876 (1990)
A new method for the efficient separation of carbon monoxide from a binary mixture of carbon monoxide and hydrogen has been established by use of a selenium/secondary amine reaction system.This system consists of the selective uptake of carbon monoxide by the reaction with selenium and secondary amines to form the corresponding ammonium carbamoselenoates (1) in solution and the release of carbon monoxide by thermolysis of 1 into starting components.The amount of separated carbon monoxide was stoichiometric and the purity was higher than 99.9percent.
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Highly selective synthesis of primary amines from amide over Ru-Nb2O5 catalysts
Guo, Wanjun,Guo, Yong,Jia, Hongyan,Liu, Xiaohui,Pan, Hu,Wang, Yangang,Wang, Yanqin,Xia, Qineng
supporting information, (2021/12/22)
Amines are an important class of compounds in natural products and medicines. The universal availability of amides provides a potential way for the synthesis of amines. Herein, Ru/Nb2O5 catalyst is demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine (as a model reaction), with up to 91.4% yield of propylamine under relatively mild conditions. Results from XPS analyses, CO chemisorption, TEM images and DRIFTS spectra revealed that the unique properties of Nb2O5 can effectively activate the C=O group of amides, and the smaller Ru particles on Nb2O5 could further promote the activation, leading to superior catalytic performance of Ru/Nb2O5 for amide hydrogenation. Meanwhile, reducing the surface acidity of Nb2O5 can greatly inhibit the side reactions to by-products, and further enhance the selectivity to amine. Moreover, this catalytic system is also applicable for the hydrogenation of a variety of amides and provides high potential for the industrial production of primary amines from amides.
Titanium-Catalyzed Hydroaminoalkylation of Ethylene
Rosien, Michael,T?ben, Iris,Schmidtmann, Marc,Beckhaus, Rüdiger,Doye, Sven
supporting information, p. 2138 - 2142 (2020/02/05)
The first examples of titanium-catalyzed hydroaminoalkylation reactions of ethylene with secondary amines are presented. The reactions can be achieved with various titanium catalysts and they do not require the use of high pressure equipment. In addition, the first solid-state structure of a titanapyrrolidine that is formed by insertion of an alkene into the Ti?C bond of a titanaaziridine is reported.
Reduction of Amides to Amines under Mild Conditions via Catalytic Hydrogenation of Amide Acetals and Imidates
Kadyrov, Renat
, p. 185 - 191 (2018/11/23)
A simple and general protocol was developed for selective conversion of amides into amines. Amides were converted into amide acetals and imido esters by O-alkylation and then hydrogenated without isolation into amines under very mild reaction conditions over standard hydrogenation catalysts. Triethyloxonium tertafluoroborate, methyl trifluoromethanesulfonate, dimethyl sulfate and ethyl chloroformate were validated as alkylating agent. The synthetic utility of this approach was demonstrated by the selective carbonyl reduction of peptide groups. Carbonyl reduction of peptide group proceeds chemoselective without racemization of the neighboring chiral center. (Figure presented.).
Sustainable hydrogenation of aliphatic acyclic primary amides to primary amines with recyclable heterogeneous ruthenium-tungsten catalysts
Coeck, Robin,Berden, Sarah,De Vos, Dirk E.
supporting information, p. 5326 - 5335 (2019/10/11)
The hydrogenation of amides is a straightforward method to produce (possibly bio-based) amines. However current amide hydrogenation catalysts have only been validated in a rather limited range of toxic solvents and the hydrogenation of aliphatic (acyclic) primary amides has rarely been investigated. Here, we report the use of a new and relatively cheap ruthenium-tungsten bimetallic catalyst in the green and benign solvent cyclopentyl methyl ether (CPME). Besides the effect of the Lewis acid promotor, NH3 partial pressure is identified as the key parameter leading to high primary amine yields. In our model reaction with hexanamide, yields of up to 83% hexylamine could be achieved. Beside the NH3 partial pressure, we investigated the effect of the catalyst support, PGM-Lewis acid ratio, H2 pressure, temperature, solvent tolerance and product stability. Finally, the catalyst was characterized and proven to be very stable and highly suitable for the hydrogenation of a broad range of amides.
Continuous Production of Dialkylamines by Selective Hydrogenation of Nitriles on a Nickel-Zeolite Catalyst
Popov, Yu. V.,Mokhov,Latyshova,Panov,Pletneva, M. Yu.
, p. 1778 - 1782 (2018/03/21)
Hydrogenation of aliphatic nitriles in the presence of nickel supported by NaX zeolite was studied. The data obtained were used to develop a continuous method for obtaining dialkylamines with the yield of the target product of up to 98%.
Colloid and nanosized catalysts in organic synthesis: XVI.1 Continuous hydrogenation of carbonitriles catalyzed by nickel nanoparticles applied on a support
Popov, Yu. V.,Mokhov,Latyshova,Nebykov,Panov,Pletneva, M. Yu.
, p. 2276 - 2281 (2017/11/24)
Conversion of the starting nitriles and selectivity of the products formation during continuous hydrogenation of various nitriles catalyzed by Ni0/Ceokar-2 have been studied as functions of temperature. Performing the process at temperature 120–260°С has led to the formation of a mixture of products containing di- and trialkylamines as well as the corresponding imines and enamines.
