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.
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.
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.
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.
One-pot conversion of lysine to caprolactam over Ir/H-Beta catalysts
Sebastian, Joby,Zheng, Mingyuan,Jiang, Yu,Zhao, Yu,Wang, Hua,Song, Zhendong,Li, Xinsheng,Pang, Jifeng,Zhang, Tao
, p. 2462 - 2468 (2019)
Amino acid lysine could serve as an ideal bio-based feedstock for the synthesis of caprolactam (CPL), which is currently a petroleum-derived monomer. Herein, we report the one-pot conversion of l-lysine to CPL via hydrogenolysis over bifunctional metal supported catalysts. Among the various hydrogenation metals and different supports, the combination of Ir and HB zeolite gave the best performance. Under optimal conditions, a 30% yield of CPL from l-lysine and a 58% yield from the reaction intermediate α-dimethyl amino caprolactam (DMAC) were obtained over a 2Ir/HB-124 catalyst at 250 °C in an autoclave or fixed-bed reactor. The reaction solvent dramatically affected the reaction selectivity, and methanol was found to be the best due to its unique contribution towards the formation of α-dimethyl amino caprolactam (DMAC) as well as the following C-N breakage of the C-N(CH3)2 bond. The acid sites on the catalyst accelerate lactam formation, and the synergy between the acid sites and hydrogenation sites favours C-N bond hydrogenolysis to produce CPL. Besides the acidity, the large pore size of HB is able to accommodate big reaction intermediate molecules inside the pores further ensures the superior performance of Ir/HB. The reaction route was identified, i.e., l-lysine first undergoes cyclization and N-methylation to DMAC, and then C-N(CH3)2 bond hydrogenolysis to form CPL. The Ir/HB catalyst has reasonably good stability and high selectivity, making this one-pot conversion process a novel and environmentally benign way of producing CPL from easily available renewable feedstocks.
A novel reaction of N-phenylthiocaprolactam: The α-sulfenylation of ketones under mild conditions
Foray, Gabriela,Penenory, Alicia B.,Rossi, Roberto A.
, p. 2035 - 2038 (1997)
N-phenylthiocaprolactam (2) reacts with the enolate anions of aliphatic, aromatic or cyclic ketone 1a-e, to give the corresponding α-phenylthioketones 3a-e. This reaction proceeds with high yields of monosulphenylation (80-97%) in DMSO under mild conditions (potassium ter-butoxide, 25°C, 10 min).
Aerobic Oxidation of Cyclic Amines to Lactams Catalyzed by Ceria-Supported Nanogold
Dairo, Taiwo O.,Nelson, Nicholas C.,Slowing, Igor I.,Angelici, Robert J.,Woo, L. Keith
, p. 2278 - 2291 (2016)
Abstract: The oxidative transformation of cyclic amines to lactams, which are important chemical feedstocks, is efficiently catalyzed by CeO2-supported gold nanoparticles (Au/CeO2) and Aerosil 200 in the presence of an atmosphere of O2. The complete conversion of pyrrolidine was achieved in 6.5?h at 160 °C, affording a 97 % yield of the lactam product 2-pyrrolidone (γ-butyrolactam), while 2-piperidone (δ-valerolactam) was synthesized from piperidine (83 % yield) in 2.5?h. Caprolactam, the precursor to the commercially important nylon-6, was obtained from hexamethyleneimine in 37 % yield in 3?h. During the oxidation of pyrrolidine, two transient species, 5-(pyrrolidin-1-yl)-3,4-dihydro-2H-pyrrole (amidine-5) and 4-amino-1-(pyrrolidin-1-yl)butan-1-one, were observed. Both of these compounds were oxidized to 2-pyrrolidone under catalytic conditions, indicating their role as intermediates in the reaction pathway. In addition to the reactions of cyclic secondary amines, Au/CeO2 also efficiently catalyzes the oxidation of N-methyl cyclic tertiary amines to the corresponding lactams at 80 and 100 °C. Graphical Abstract: [Figure not available: see fulltext.]
Effective depolymerization of nylon-6 in wet supercritical hydrocarbons
Kaiso, Kouji,Sugimoto, Tsunemi,Kashiwagi, Kohichi,Kamimura, Akio
, p. 370 - 371 (2011)
Treatment of nylon-6 with supercritical toluene in the presence of small amounts of water resulted in an effective conversion of polyamide to give ε-caprolactam in quantitative yield. The presence of a small amount of water is critical for the progress of the reaction; completely anhydrous conditions failed to achieve depolymerization. ε-Caprolactam was readily isolated after the removal of toluene under reduced pressure. The present method can serve as a useful treatment for the effective chemical recycling of waste plastics. The combined use of hydrocarbon and water is a new technique to control the reactivity of hightemperature water.
An alternative efficient method for transformation of thiocarbonyl to carbonyl group using trifluoroacetic anhydride
Masuda, Ryoichi,Hojo, Masaru,Ichi, Tadaaki,Sasano, Shigetoshi,Kobayashi, Tatsuya,Kuroda, Chihiro
, p. 1195 - 1198 (1991)
A simple and efficient procedure for the rapid and mild conversion of thiocarbonyls to carbonyls in high yields is described.
Dehydration of 5-amino-1-pentanol over rare earth oxides
Ohta, Kaishu,Yamada, Yasuhiro,Sato, Satoshi
, p. 73 - 80 (2016)
Vapor-phase catalytic dehydration of 5-amino-1-pentanol was investigated over various oxide catalysts including rare earth oxides (REOs). Over ordinary acidic oxides such as Al2O3, SiO2, SiO2-Al2O3, TiO2, and ZrO2, a cyclic amine such as piperidine was mainly produced at temperatures of 300 °C and higher. In contrast, basic REOs with a cubic bixbyite structure showed the catalytic activity in the conversion of 5-amino-1-pentanol to produce 4-penten-1-amine at 425 °C. In REO catalysts, Tm2O3, Yb2O3, and Lu2O3 showed the high conversion of 5-amino-1-pentanol and the high selectivity to 4-penten-1-amine. Especially, Yb2O3 calcined at 800 °C showed a high formation rate of 4-penten-1-amine with the selectivity of ca. 90% at 425 °C. In comparing the reactivity of several amino alcohols to form the corresponding unsaturated amines, Yb2O3 effectively catalyzed the dehydration of 6-amino-1-hexanol into 5-hexen-1-amine, whereas 3-amino-1-propanol and 4-amino-1-butanol were not effectively dehydrated due to the decomposition of the reactant.
N-ACETYL-ε-AMINOCAPROIC ACID. IV. HYDROLYSIS OF N-ACETYL-ε-CAPROLACTAM
Yasnitskii, B. G.,Dol'berg, E. B.,Spivak, A. L.
, p. 60 - 63 (1980)
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VAPOR-PHASE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME OVER BORIA-HYDROXYAPATITE CATALYST
Izumi, Yusuke,Sato, Satoshi,Urabe, Kazuo
, p. 1649 - 1652 (1983)
The boron trioxide coupled with hydroxyapatite was found to catalyze the Beckmann rearrangement of cyclohexanone oxime in the vapor phase at 300 deg C more selectively than boria-alumina and silica-alumina.The basic property of hydroxyapatite appears to play an important role in effecting the rearrangement selectively.
Strong basic sites accelerate the deactivation of oxide catalysts supported on FSM-16 for the vapor-phase beckmann rearrangement of cyclohexanone oxime
Shouro, Daisuke,Nakajima, Tsuyoshi,Mishima, Shozi
, p. 1319 - 1320 (1999)
The acidic and basic properties of FSM-16-supported Al2O3, ZnO or CdO were determined by the temperature-programmed desorption (TPD) of ethylamine. Relationship of the deactivation rate of the catalyst during the vapor-phase Beckmann rearrangement with the acidic and basic properties was studied. It was found that the deactivation was accelerated with an increase in the amount of the strong basic sites.
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Just,Cunningham
, p. 1151 (1972)
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Collum,D.B. et al.
, p. 4393 - 4394 (1978)
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Tada,Tokura
, p. 387 (1958)
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Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam in a modified catalytic system of trifluoroacetic Acid
Zhang,Riaud,Wang,Lu,Luo
, p. 151 - 157 (2014)
A catalytic system, including trifluoroacetic acid and organic solvent additives, was applied to carry out the Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. High conversion (100%) and high selectivity to caprolactam (>99%) have been successfully obtained using acetonitrile as the additive. The effect of several organic solvents on the reaction was investigated, and the catalyst composition was optimized. The results indicate that the catalytic system with 10 wt% of acetonitrile can give the fastest reaction rate. An immiscible twophase system was proposed to study the side reaction of oxime hydrolysis which determines the selectivity. Based on the results, a simplified reaction process was suggested and a mathematical kinetic model was developed. The performance of the catalytic system is much better than the classic process. Neutralization agent and ammonium sulfate by-product are both completely avoided.
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Ohno,Sakai
, p. 4541 (1965)
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Beckmann rearrangement of cyclohexanone oxime over borate-pillared LDHs
Lin, Jenn-Tsuen
, p. 779 - 787 (1999)
Borate-pillared layered double hydroxides (LDHs) were studied as catalysts in vapor-phase Beckmann rearrangement of cyclohexanone oxime to caprolactam under atmospheric pressure. The results were compared with those over the physical admixture of LDH and boria, the co-precipitate of B-Mg-Al hydroxide, and the pristine LDH and boria compounds. Although oxime conversion and caprolactam selectivity declined with time-on-stream over all the catalysts, borate-pillared LDH catalysts could retain activity longer than pure boria or those prepared by other methods. The decay rate however was affected by the Mg/Al ratio, the boron content and the form of LDH precursor used. The LDH itself functioning as a basic catalyst contributed to the formation of side products such as cyclohexanone and 2-cyclohexen-1-one. The physical admixtures of LDH and boria had catalytic properties more close to that of pure boria, which gave high caprolactam selectivities but lost the activity in several hours on stream. The high resistance to decay of the pillared catalysts was attributed to that boria in the interlayer of LDH was stabilized and prevented from structural transformation to a glassy state of no activity.
Scott et al.
, p. 1815,1819 (1954)
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Grakauskas,V. et al.
, p. 3839 - 3841 (1968)
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Enzymatic formation of lactams in organic solvents
Gutman, Arie L.,Meyer, Elazar,Yue, Xu,Abell, Chris
, p. 3943 - 3946 (1992)
Porcine pancreatic lipase in organic solvents catalyses the intramolecular cyclisation of aminoesters and the formation of macrocyclic bislactams from diesters and diamines.
A new procedure to obtain ?-caprolactam catalyzed by a guanidinium salt
Fernández-Stefanuto,Verdía,Tojo
, p. 12830 - 12834 (2017)
A new procedure to prepare ?-caprolactam by the Beckmann rearrangement of cyclohexanone oxime is described. Treatment of the oxime with the novel salt cyanoguanidinium tosylate affords ?-caprolactam without the need of any other promoter.
PREPARATION METHOD OF CAPROLACTAM
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, (2022/03/14)
The present disclosure discloses a method for preparing caprolactam including: (1) contacting cyclohexanone oxime with a catalyst to carry out reaction in the presence of ethanol and under the condition of gas phase Beckmann rearrangement reaction of cyclohexanone oxime; (2) separating the reaction product obtained in step (1) to produce an ethanol solution of crude caprolactam, and then separating the ethanol solution of crude caprolactam to obtain ethanol and crude caprolactam; (3) removing impurities with boiling points lower than that of caprolactam in the crude caprolactam to obtain a light component removal product; (4) mixing the light component removal product with a crystallization solvent to carry out crystallization and solid-liquid separation to obtain a crystalline crystal; (5) subjecting the crystalline crystal to a hydrogenation reaction; wherein the crystallization solvent contains 0.1-2 wt % of ethanol.
Efficient nitriding reagent and application thereof
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Paragraph 0533-0535, (2021/03/31)
The invention discloses an efficient nitriding reagent and application thereof, wherein the nitriding reagent comprises nitrogen oxide, an active agent, a reducing agent and an organic solvent. By applying the nitriding reagent, nitrogen-containing compounds such as amide, nitrile and the like can be produced, and the method is simple in condition, low in waste discharge amount and simple in reaction equipment.
