Xn:Harmful;
105-60-2Relevant articles and documents
Hierarchical silicalite-1 octahedra comprising highly-branched orthogonally-stacked nanoplates as efficient catalysts for vapor-phase Beckmann rearrangement
Chang, Albert,Hsiao, Hsu-Ming,Chen, Tsai-Hsiu,Chu, Ming-Wen,Yang, Chia-Min
, p. 11939 - 11942 (2016)
A triblock structure-directing agent was designed to synthesize hierarchical silicalite-1 octahedra comprising highly-branched, orthogonally-stacked and self-pillared nanoplates that exhibited excellent and stable activity for the vapor-phase Beckmann rearrangement of cyclic oximes and high lactam selectivity.
VAPOR-PHASE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME OVER SILICA-BORIA CATALYST PREPARED BY CHEMICAL VAPOR DEPOSITION METHOD
Sato, Satoshi,Sakurai, Hiroaki,Urabe, Kazuo,Izumi, Yusuke
, p. 277 - 278 (1985)
Cyclohexanone oxime was converted to ε-caprolactam in a high yield of 93percent at 250 deg over a silica-supported boron oxide catalyst which was prepared by means of chemical vapor deposition.This catalyst was much more efficient than silica-boria and alumina-boria which were obtained by the usual impregnation method.
Active Sites for the Liquid-Phase Beckmann Rearrangement of Cyclohexanone, Acetophenone and Cyclododecanone Oximes, Catalyzed by Beta Zeolites
Camblor,Corma,Garcia,Semmer-Herledan,Valencia
, p. 267 - 272 (1998)
The Beckmann rearrangement of oximes with different molecular sizes, i.e. cyclohexanone, cyclododecanone, and acetophenone oximes, has been studied in liquid phase at 130°C over a series of four Beta zeolites differing in the presence or absence of framework Al and internal silanol groups. When the zeolite does not contain framework Al and internal silanols, no appreciable conversion was observed. The catalyst having internal silanol groups but no framework Al exhibits oxime conversion, but the selectivity to the corresponding amide is low in some cases. In the Beta zeolite without silanol groups but containing framework Al, conversion and selectivity were found to be very high. This superior performance of Broensted acid sites, compared to silanol groups, shows that the results reported for the vapor phase reaction cannot be extrapolated when the reaction is performed in liquid phase. Finally, as could be anticipated according to the dimensions of the micropores, it is shown that H-Beta zeolites exhibit a much better catalytic performance than H-ZSM-5 zeolite for larger sized oximes.
Ammoximation of cyclohexanone by nitric oxide and ammonia: A One-step process for synthesis of polycaprolactam
Prasad,Vashisht, Seema
, p. 373 - 376 (1996)
Catalytic transformation of cyclohexanone by nitric oxide and ammonia to cyclohexanone oxime, its rearrangement to caprolactam, and its polymerization to polycaprolactam has been studied in the liquid phase over solid catalysts. The influence of various catalysts and process parameters on the oximation reaction is reported. A maximum yield of 37.78% with a selectivity of 80.95% for caprolactam could be achieved, over a synthetically prepared Al2O3-SiO2 catalyst, at a cyclohexanone : NO : NH3 molar ratio of 1:2.9:1.7 and a temperature of 348 K. In this process the production of oxime and its rearrangement to caprolactam occur simultaneously. The resulting caprolactam polymerises later to give a molecular weight ranging from 500 to 5000. A tentative mechanism for the reactions is suggested.
Porous aluminosilicate inorganic polymers (geopolymers): a new class of environmentally benign heterogeneous solid acid catalysts
Alzeer, Mohammad I.M.,MacKenzie, Kenneth J.D.,Keyzers, Robert A.
, p. 173 - 181 (2016)
Aluminosilicate inorganic polymers (geopolymers) were developed as a new class of cost-efficient, environmentally friendly, solid acid catalysts and their performance evaluated in a model liquid-phase Beckmann rearrangement reaction (cyclohexanone oxime to ε-caprolactam). The active sites were generated within the structure of the geopolymers by ion-exchange with NH4+ followed by thermal treatment. The effect of varying the starting composition on the textural and acidic properties of the geopolymer catalysts was studied and its influence on the catalytic activity was investigated. Catalytic performance was significantly improved by the use of post-synthetic treatments. No significant decrease in the yield of ε-caprolactam after recycling for five times suggesting that geopolymer-based catalysts are advantageous over supported catalysts which often lose their catalytic activity due to leaching of the active sites from the support. The catalytic activities obtained in this study are comparable, and sometimes superior, to other solid catalysts suggesting that geopolymers have a great potential as environmentally benign heterogeneous catalysts.
An Integrated Cofactor/Co-Product Recycling Cascade for the Biosynthesis of Nylon Monomers from Cycloalkylamines
Sarak, Sharad,Sung, Sihyong,Jeon, Hyunwoo,Patil, Mahesh D.,Khobragade, Taresh P.,Pagar, Amol D.,Dawson, Philip E.,Yun, Hyungdon
, p. 3481 - 3486 (2021)
We report a highly atom-efficient integrated cofactor/co-product recycling cascade employing cycloalkylamines as multifaceted starting materials for the synthesis of nylon building blocks. Reactions using E. coli whole cells as well as purified enzymes produced excellent conversions ranging from >80 and 95 % into desired ω-amino acids, respectively with varying substrate concentrations. The applicability of this tandem biocatalytic cascade was demonstrated to produce the corresponding lactams by employing engineered biocatalysts. For instance, ?-caprolactam, a valuable polymer building block was synthesized with 75 % conversion from 10 mM cyclohexylamine by employing whole-cell biocatalysts. This cascade could be an alternative for bio-based production of ω-amino acids and corresponding lactam compounds.
Amino-alcohol cyclization: Selective synthesis of lactams and cyclic amines from amino-alcohols
Pingen, Dennis,Vogt, Dieter
, p. 47 - 52 (2014)
By employing an amination catalyst, previously used in the direct synthesis of amines from alcohol with ammonia, n-amino-alcohols could be selectively cyclized to either the amide or the amine. By the addition of water, the amine could be produced as the major product whereas adding a sacrificial ketone as a hydrogen acceptor resulted in the amide as the major product. Without an additive a mixture of both the amine and the amide was observed. N-substituted amino-alcohols solely gave cyclic amines under these conditions. From 2-(n-alkanol) anilines the cyclic amines were produced, where the n-propanol derivative selectively formed quinoline as the major product.
Catalytic properties of WOx/SBA-15 for vapor-phase Beckmann rearrangement of cyclohexanone oxime
Bordoloi, Ankur,Halligudi
, p. 141 - 147 (2010)
WOx/SBA-15 nanocomposite materials with different WOx loadings were prepared by one step hydrothermal synthesis and used in the vapor-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. The catalysts were thoroughly characterized by X-ray diffraction (XRD), sorption analysis, energy dispersive X-ray analysis (EDAX) and Raman spectroscopy. The acidities of the catalysts were estimated by ammonia temperature programmed desorption (NH3-TPD) and Fourier transform infrared studies of adsorbed pyridine (pyridine-FTIR). The optimum temperature for the Beckmann rearrangement was 350 °C. Using WOx/SBA-15(20) under the vapor-phase reaction conditions [temperature = 350 °C, WHSV = 0.6 h-1, oxime concentration = 2.5% (w/w) in MeOH] gave 79% cyclohexanone oxime conversion with 93%, ε-caprolactam selectivity. The ε-caprolactam selectivity was found to be dependent on temperature and space velocity. A correlation has been made between the rearrangement activity and acidity and the structural properties of the catalysts.
Weil-defined N-heterocyclic carbene based ruthenium catalysts for direct amide synthesis from alcohols and amines
Zhang, Yao,Chen, Cheng,Ghosh, Subhash Chandra,Li, Yongxin,Hong, Soon Hyeok
, p. 1374 - 1378 (2010)
Well-defined N-heterocyclic carbene based ruthenium, complexes were developed as highly active catalysts for direct amide synthesis from alcohols and amines. A catalytic amount of a base such, as KO1Bu was essential to initiate the catalytic cycle. Activity of the Ru complexes was comparable with the reported in situ Ru catalysts. These catalysts provided mechanistic insight suggesting a Ru hydride species as an active catalytic intermediate. The generation of the Ru hydride was critical for the amidation of free aldehydes.
Construction of tertiary chiral centers by Pd-catalyzed asymmetric allylic alkylation of prochiral enolate equivalents
Kita, Yusuke,Numajiri, Yoshitaka,Okamoto, Noriko,Stoltz, Brian M.
, p. 6349 - 6353 (2015)
Abstract The palladium-catalyzed decarboxylative allylic alkylation of enol carbonates derived from lactams and ketones is described. Employing these substrates with an electronically tuned Pd catalyst system trisubstituted chiral centers are produced. These stereocenters have been previously challenging to achieve using Pd complex/chiral P-N ligand systems.
