- Hierarchical silicalite-1 octahedra comprising highly-branched orthogonally-stacked nanoplates as efficient catalysts for vapor-phase Beckmann rearrangement
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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.
- Chang, Albert,Hsiao, Hsu-Ming,Chen, Tsai-Hsiu,Chu, Ming-Wen,Yang, Chia-Min
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- VAPOR-PHASE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME OVER SILICA-BORIA CATALYST PREPARED BY CHEMICAL VAPOR DEPOSITION METHOD
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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.
- Sato, Satoshi,Sakurai, Hiroaki,Urabe, Kazuo,Izumi, Yusuke
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- Active Sites for the Liquid-Phase Beckmann Rearrangement of Cyclohexanone, Acetophenone and Cyclododecanone Oximes, Catalyzed by Beta Zeolites
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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.
- Camblor,Corma,Garcia,Semmer-Herledan,Valencia
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- Ammoximation of cyclohexanone by nitric oxide and ammonia: A One-step process for synthesis of polycaprolactam
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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.
- Prasad,Vashisht, Seema
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- Porous aluminosilicate inorganic polymers (geopolymers): a new class of environmentally benign heterogeneous solid acid catalysts
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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.
- Alzeer, Mohammad I.M.,MacKenzie, Kenneth J.D.,Keyzers, Robert A.
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- An Integrated Cofactor/Co-Product Recycling Cascade for the Biosynthesis of Nylon Monomers from Cycloalkylamines
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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.
- Sarak, Sharad,Sung, Sihyong,Jeon, Hyunwoo,Patil, Mahesh D.,Khobragade, Taresh P.,Pagar, Amol D.,Dawson, Philip E.,Yun, Hyungdon
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- Amino-alcohol cyclization: Selective synthesis of lactams and cyclic amines from amino-alcohols
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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.
- Pingen, Dennis,Vogt, Dieter
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- Catalytic properties of WOx/SBA-15 for vapor-phase Beckmann rearrangement of cyclohexanone oxime
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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.
- Bordoloi, Ankur,Halligudi
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- Weil-defined N-heterocyclic carbene based ruthenium catalysts for direct amide synthesis from alcohols and amines
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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.
- Zhang, Yao,Chen, Cheng,Ghosh, Subhash Chandra,Li, Yongxin,Hong, Soon Hyeok
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- Construction of tertiary chiral centers by Pd-catalyzed asymmetric allylic alkylation of prochiral enolate equivalents
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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.
- Kita, Yusuke,Numajiri, Yoshitaka,Okamoto, Noriko,Stoltz, Brian M.
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- One-pot conversion of lysine to caprolactam over Ir/H-Beta catalysts
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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.
- Sebastian, Joby,Zheng, Mingyuan,Jiang, Yu,Zhao, Yu,Wang, Hua,Song, Zhendong,Li, Xinsheng,Pang, Jifeng,Zhang, Tao
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- Preparation of SiO2-Al2O3 and its supported Co3O4 Catalysts for nitrosation of cyclohexane
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Amorphous SiO2-Al2O3 was prepared by sol-gel method and cobalt oxide supported on SiO2-Al 2O3 was prepared by impregnation method. These materials were characterized by BET, XRD, TPD and FT
- Liu, Pingle,Xie, Huan,You, Kuiyi,Hao, Fang,Li, Xiaofeng,Luo, He'An
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- A novel reaction of N-phenylthiocaprolactam: The α-sulfenylation of ketones under mild conditions
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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).
- Foray, Gabriela,Penenory, Alicia B.,Rossi, Roberto A.
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- Lysine-based functional blocked isocyanates for the preparation of polyurethanes provided with pendant side groups
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This article describes a methodology to prepare polyurethanes (PUs), decorated with pendant (bio)functional side groups, by polymerizing (bio)functionalized blocked diisocyanates with polyols. Caprolactam blocked lysine diisocyanate methyl ester (BLDI-OMe) was prepared in high yields, by reacting the methyl ester of lysine with carbonyl biscaprolactam. In the absence of a catalyst, the polymerization of BLDI-OMe with polycaprolactone and polytetrahydrofuran resulted in strictly linear PUs due to the high selective reactivity of the blocked isocyanates (BIs). Although the ester appeared to be less reactive, we found hydrolyzing conditions for the ester, without affecting the BIs. The free acid groups were converted into a N-hydroxysuccinimide (NHS) activated ester, which was a versatile intermediate for further functionalization. After having demonstrated that model amines were able to substitute NHS without effecting the BIs groups, the same chemistry was used to couple biotin, giving a biotin functional caprolactam blocked lysine diisocyanate. The polymerization with polyols afforded the corresponding biotin-functional PUs.
- Yin, Jie,Wildeman, Jur,Loontjens, Ton
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- Aerobic Oxidation of Cyclic Amines to Lactams Catalyzed by Ceria-Supported Nanogold
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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.]
- Dairo, Taiwo O.,Nelson, Nicholas C.,Slowing, Igor I.,Angelici, Robert J.,Woo, L. Keith
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- Ring contraction of N-chlorolactams, a novel rearrangement
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Upon photolysis in methylene chloride at -78 °C, different N-chlorolactams underwent a novel ring contraction to the corresponding carbamoyl chlorides, which were converted to the methyl carbamates. The rearrangement is 100% stereoselective, occurring with retention of configuration at the migrating carbon center. The yields of isolated carbamates ranged from 40% to 57%, the other product being the parent lactam, 18% to 38%.
- Drouin, Alexandre,Lessard, Jean
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- Effective depolymerization of nylon-6 in wet supercritical hydrocarbons
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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.
- Kaiso, Kouji,Sugimoto, Tsunemi,Kashiwagi, Kohichi,Kamimura, Akio
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- Establishment of an activated peroxide system for low-temperature cotton bleaching using N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride
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Cotton bleaching is traditionally carried out in strongly alkaline solution of hydrogen peroxide (H2O2) at temperatures close to the boil. Such harsh processing conditions can result in extensive water and energy consumptions as well as severe chemical damage to textiles. In this study, an activated peroxide system was established for low-temperature cotton bleaching by incorporating a bleach activator, namely N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC) into an aqueous H2O2 solution. Experimental results showed that the TBBC-activated peroxide system exhibited the most effective bleaching performance in a pH range of 6-8 which could be approximated by adding sodium bicarbonate (NaHCO3). The TBBC/H2O2/NaHCO3 system led to rapid bleaching of cotton at a temperature as low as 50°C. In comparison with the hot alkaline peroxide bleaching system, the TBBC/H2O2/NaHCO3 system provided cotton fabric with an equivalent degree of whiteness, higher degree of polymerization, and slightly lower water absorbency. The new activated peroxide system may provide a more environmentally benign approach to cotton bleaching.
- Xu, Changhai,Hinks, David,Sun, Chang,Wei, Qufu
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- An alternative efficient method for transformation of thiocarbonyl to carbonyl group using trifluoroacetic anhydride
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A simple and efficient procedure for the rapid and mild conversion of thiocarbonyls to carbonyls in high yields is described.
- Masuda, Ryoichi,Hojo, Masaru,Ichi, Tadaaki,Sasano, Shigetoshi,Kobayashi, Tatsuya,Kuroda, Chihiro
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- Light-enhanced acid catalysis over a metal-organic framework
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A Br?nsted acid-functionalized metal-organic framework (MOF), MIL-101-SO3H, was prepared for acid-engaged esterification reactions. Strikingly, for the first time, the MOF exhibits significantly light-enhanced activity and possesses excellent activity and recyclability, with even higher activity than H2SO4 under light irradiation.
- Xu, Caiyun,Sun, Keju,Zhou, Yu-Xiao,Ma, Xiao,Jiang, Hai-Long
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- Dehydration of 5-amino-1-pentanol over rare earth oxides
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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.
- Ohta, Kaishu,Yamada, Yasuhiro,Sato, Satoshi
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- Thermal alkylation of ambidentate lactams with 2-(perfluoroalkyl)-1-iodoalkanes. The effect of reaction conditions and ring size on the synthesis of 2-(perfluoroalkyl)ethanols and the mechanism of reaction
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The perfluoroalkylated long chain alcohols and their derivatives exhibit strong surface activity in solution and novel surface modification properties as adsorbed layers or films. A new, little known synthesis of 2-(perfluoroalkyl)ethanols (R(F)CH2CH2OH) employs a lactam, e.g., 2-pyrrolidinone (2), with an iodoalkane, e.g., C6F13CH2CH2I (1). Alkylation of 2 by heating with 1 gives C6F13CH2CH2OH (3) in 83% distilled yield, and treating the residual lactim ether salt (6·HI) with K2CO3 gives additional 3, up to 94% yield. Rate of alcohol formation (k(alc)) is unaffected by molar ratio of 2:1, yet rate of 1 reaction (k(iodo)) increases 2.44 times with doubling of 2:1 and side product C6F13CH = CH2 (4) decreases from 4 to 2%. For homologous lactams [(CH2)(n)NHC = O] (n = 3-5), selectivities (mol 3:4) are as follows: 5-membered ring, 18.4; 6-membered ring, 0.73; 7-membered ring, 0.13. Conversions to 3 are as follows: 6-membered ring, 19.4%; and 7-membered ring, 1.75%. A three-stop mechanism is proposed: (1) O-alkylation of the lactam by 1 gives lactim salt I; (2) N-substitution of salt I by another molecule of lactam forms a tetrahedral adduct (II); (3) breakdown of salt II gives 3 and iminolactam salt III. In model experiments, heating of 2 and lactim 6 yields 99% of 3 and iminolactam 5 and 1% of 4. By contrast, 7-membered 14 with 2 gives 45% of 3 and iminolactam 12, besides 4 and -caprolactam 16 (20%). For higher lactams, two competitive reactions can be discerned: (1) the S(N)2 displacement of alcohol by N-attack on salt II and a unimolecular, concerted fragmentation of the lactim, to lactam and alkene.
- Brace
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- VAPOR-PHASE BECKMANN REARRANGEMENT OF CYCLOHEXANONE OXIME OVER BORIA-HYDROXYAPATITE CATALYST
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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.
- Izumi, Yusuke,Sato, Satoshi,Urabe, Kazuo
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- Mechanistic insight into self-propagation of organo-mediated beckmann rearrangement: A combined experimental and computational study
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Organo-mediated Beckmann rearrangement in the liquid phase, which has the advantage of high efficiency and straightforward experimental procedures, plays an important role in the synthesis of amides from oximes. However, the catalytic mechanisms of these organic-based promoters are still not well understood. In this work, we report a combined experimental and computational study on the mechanism of Beckmann rearrangement mediated by organic-based promoters, using TsCl as an example. A novel self-propagating cycle is proposed, and key intermediates of this self-propagating cycle are confirmed by both experiments and DFT calculations. In addition, the reason why cyclohexanone oxime is not a good substrate of the organo-mediated Beckmann rearrangement is discussed, and a strategy for improving the yield is proposed.
- An, Na,Tian, Bo-Xue,Pi, Hong-Jun,Eriksson, Leif A.,Deng, Wei-Ping
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- Strong basic sites accelerate the deactivation of oxide catalysts supported on FSM-16 for the vapor-phase beckmann rearrangement of cyclohexanone oxime
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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.
- Shouro, Daisuke,Nakajima, Tsuyoshi,Mishima, Shozi
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- Novel mesoporous silicoaluminophosphates as highly active and selective materials in the Beckmann rearrangement of cyclohexanone and cyclododecanone oximes
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Novel mesoporous silicoaluminophosphate molecular sieves with an MCM-41 type structure were synthesized and characterized using various techniques, including XRD, N2 adsorption, DRIFT, TEM, and 27Al, 29Si, and 31P MAS NMR. The surface acidity of the materials was determined by using pyridine and 2,6-dimethylpyridine as probe molecules. The catalytic activity of the mesoporous silicoaluminophosphates in the Beckmann rearrangement of cyclohexanone and cyclododecanone oximes was investigated and compared under gas- and liquid-phase (conventional vs microwave-assisted heating) conditions. The mesoporous silicoaluminophosphate materials are extremely active and selective in both reactions, giving yields comparable to those obtained on aluminosilicates and zeolites in the case of the vapor-phase Beckmann rearrangement of cyclohexanone oxime and the microwave-assisted Beckmann rearrangement of cyclododecanone oxime, respectively. The materials were also highly reusable after reactivation in vapor-phase reactions, with an increase in selectivity to the oxime, although a decrease in the durability (expressed as lifetime at quantitative conversion of the oxime) was also found.
- Conesa,Mokaya,Yang,Luque,Campelo,Romero
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- Thermolysis Reaction of 2-Acetyl-1-Oxo-Five-, Six-, and Seven-Membered Ring
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The rates of gas-phase thermolysis reactions of 2-acetylcyclopentanone 1, 2-acetylcyclohexanone 2, N-acetylcaprolactam 3, 2-acetylbutyrolactone 4, 2-acetyl-2-methylbutyrolactone 5, and 3-acetyl-2-oxazolidinone 6 have been measured over a temperature range of 50 K.They undergo unimolecular first-order elimination reactions for which log A = 11.7, 11.7, 11.2, 11.4, 11.5, and 11.1 s-1 and Ea = 193.4, 189.5, 153.2, 201.0, 206.8, and 176.1 kJ mol-1, respectively.The effect of the ring size together with the effect of a heteroatom in the ring on the rate of thermolysis reactions for compounds 1-6 is the subject of this work.
- Al-Awadi, Nouria A.,Mathew, Tommy
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- High temperature calcination for a highly efficient and regenerable B2O3/ZrO2 catalyst for the synthesis of ε-caprolactam
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High temperature calcination of boria-supported zirconia leads to highly selective and regenerable B2O3/ZrO2 catalysts for the synthesis of ε- caprolactam by Beckmann rearrangement of cyclohexanone oxime.
- Xu, Bo-Qing,Cheng, Shi-Biao,Zhang, Xin,Ying, Shuang-Feng,Zhu, Qi-Ming
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- Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam in a modified catalytic system of trifluoroacetic Acid
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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.
- Zhang,Riaud,Wang,Lu,Luo
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- Amide (A)–thioamide (T) interconversions using Ph3SiSH (A to T) and Ph3SnOH (T to A) reagents
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Ph3SiSH transforms amides to thioamides and Ph3SnOH performs the reverse process, with the concomitant formation of Ph3SiOH (or Ph3SiOSiPh3) and Ph3SnSSnPh3, respectively. The chemistry is a delightful illustration of the oxophilicity of silicon compared to the thiophilicity of tin and occurs under relatively mild conditions, and for amide to thioamide transformation requires no amide activation. The chemistry is in accord with available data for Si?(S)(O), Sn?(O)(S) and C?(O)(S) bond energies. Copyright
- Arias-Ugarte, Renzo N,Sharma, Hemant K,Pannell, Keith H
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- Dehydrogenative Oxidation of Cyclic Amines on a Diruthenium Complex
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The dehydrogenative oxidation of cyclic amines catalyzed by a diruthenium complex and mechanistic studies are described. Cyclic amines and water reacted in the presence of Cp?Ru(μ-H)4RuCp? (1) (Cp? = 1,2,4-tri-tert-butylcyclopentadienyl) to afford lactams accompanied by elimination of the hydrogen gas. The reaction of hexamethylenimine with 1 at 160 °C afforded Cp?Ru(μ-H)2(μ-C6H11N)RuCp? (2), having a novel μ-cyclic imine ligand through N-H and C-H bond cleavages. Further C-H bond cleavage of 2 proceeded at 180 °C to afford Cp?Ru(μ-H)(μ-η2:η2-C6H10N)RuCp? (4), having a perpendicularly coordinated imidoyl ligand. Complex 4 readily reacted with water and liberated -caprolactam. The cooperative interaction of the two ruthenium atoms leading to N-H and double C-H bond cleavages was the key to the dehydrogenative oxidation of cyclic amines.
- Shimogawa, Ryuichi,Fujita, Ryosuke,Takao, Toshiro,Suzuki, Hiroharu
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- Beckmann rearrangement of cyclohexanone oxime over borate-pillared LDHs
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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.
- Lin, Jenn-Tsuen
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- Selective production of ε-caprolactam via liquid-phase Beckmann rearrangement of cyclohexanone oxime over HUSY catalyst
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ε-Caprolactam was selectively produced through the liquid-phase Beckmann rearrangement of cyclohexanone oxime over HUSY catalyst when the by-products formation was effectively retarded by blockage of the corresponding active centers of pre-adsorbed water and benzonitrile molecules.
- Ngamcharussrivichai, Chawalit,Wu, Peng,Tatsumi, Takashi
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- Vapor-phase Beckmann rearrangement of cyclohexanone oxime over halide cluster catalysts
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When a silica gel-supported tungsten halide cluster with an octahedral metal framework, (H3O)2[(W6Cl 8)Cl6]·6H2O/SiO2, is treated in a helium stream in the temperature range 250-350 °C, catalytic activity for the Beckmann rearrangement of cyclohexanone oxime develops. Niobium and tantalum clusters with the same metal framework also catalyze the reaction. Cyclopentanone oxime and acetone oxime also undergo Beckmann rearrangements over the tungsten cluster. The weak Br?nsted acidity (H0 ≈ +1.5) of the hydroxo ligand, which is developed on the activated cluster, is favorable for the rearrangement.
- Nagashima, Sayoko,Kamiguchi, Satoshi,Ohguchi, Satoshi,Chihara, Teiji
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Read Online
- Enzymatic formation of lactams in organic solvents
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Porcine pancreatic lipase in organic solvents catalyses the intramolecular cyclisation of aminoesters and the formation of macrocyclic bislactams from diesters and diamines.
- Gutman, Arie L.,Meyer, Elazar,Yue, Xu,Abell, Chris
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Read Online
- Vapor phase Beckmann rearrangement using high silica zeolite catalyst
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Vapor phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam has been studied using high silica zeolite catalysts. Catalysts with different crystal sizes and gel-ageing times have been activated by ionic exchange in different conditions by means of a highly basic solution and a nearly neutral solution both containing ammonium salts. Samples have been calcined at different temperatures in order modify the number of defective sites. We observed that samples exchanged by means of a highly basic solution (pH > 10)1.2 and calcined at a relatively lower temperature (450°C) show the most interesting catalytic results. X-ray powder diffraction patterns of these samples show2 retention of the unit cell symmetry (orthorhombic cell) if compared to the dried sample. NH 3-TPD confirms the low acidity of high silica zeolites, however a higher amount of desorbed ammonia is observed for the samples exchanged at higher pH and calcined at 450°C. Due to silanol nests the IR spectra of the same samples show the formation of Si-NH2 bonds which are absent in the same material exchanged by other methods. Such sites seem to promote the high stability of the high silica zeolite catalysts also to the regeneration which is needed to remove the heavy carbonaceous compounds from the catalyst surface.
- Forni,Fornasari,Giordano,Lucarelli,Katovic,Trifiro,Perri,Nagy
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Read Online
- A new procedure to obtain ?-caprolactam catalyzed by a guanidinium salt
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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.
- Fernández-Stefanuto,Verdía,Tojo
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Read Online
- Gas-phase catalytic Beckmann rearrangement over crystalline BPO4 of dehydration ability
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The crystalline BPO4 with a P/B ratio around 1.5 prepared by dehydration of boric and phosphoric acid was found to be an effective heterogeneous catalyst for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. Copyright
- Tsuji, Hideto,Setoyama, Tohru
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Read Online
- PREPARATION METHOD OF CAPROLACTAM
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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.
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- Tandem Synthesis of ?-Caprolactam from Cyclohexanone by an Acidified Metal-organic Framework
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Tandem synthesis of ?-caprolactam, one of the largest scaled commercial chemicals, is highly desired from the viewpoint of cost, energy, and environment. However, relevant studies have remained largely underexplored. By using a one-pot strategy, we encapsulated phosphotungstic acid (PTA) into a chromium terephthalate metal-organic framework (MOF), MIL-101, for the efficient tandem conversion of cyclohexanone to ?-caprolactam. The highly dispersed PTA in the MOF matrix showed a high yield of ?-caprolactam through a tandem oximation-Beckmann rearrangement reaction at 100 °C for 12 h. Moreover, MIL-101-PTA was recycled three times, with only a slight loss in their catalytic performance. To the best of our knowledge, this represents the first report using acidified MOF for a tandem oximation-Beckmann rearrangement reaction.
- Chen, Jingwen,Chen, Minda,Cruz, Andrew,Huang, Wenyu,Li, Xinle,Liu, Tianqing,Pei, Yuchen,Wu, Xun,Zhang, Biying
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p. 3084 - 3089
(2021/07/02)
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- Efficient nitriding reagent and application thereof
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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.
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Paragraph 0533-0535
(2021/03/31)
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- Trifluoroacetic Acid Hydroxylamine System as Organocatalyst Reagent in a One-Pot Salt Free Process for the Synthesis of Caprolactam and Amides of Industrial Interest
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In this work we studied the reactivity of the Trifluoroacetic acid hydroxylamine system in the one step salt free synthesis of amides from ketones. A particular regards was paid to the caprolactam synthesis because of its industrial relevance. Synthesis, reactivity and characterization of the hydroxylamine trifluoroacetate is given. Fast oximation reaction of several ketones was gained at room temperature (1?h of reaction quantitative conversion for several ketones). In the same reactor, by raising the temperature at 383?K, the Beckmann rearrangement of the so obtained oximes is easily accomplished in the presence of three equivalent of TFA. The possibility of obtaining the trifluoroacetate of the hydroxylamine with a modified nitric acid hydrogenation reactions was verified, too. Reuse of solvent and trifluoroacetic acid is easily achieved by distillation. Graphical abstract: Salt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent.[Figure not available: see fulltext.].
- Manente,Pietrobon,Ronchin,Vavasori
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p. 3543 - 3549
(2021/03/30)
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- Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino) Acetate (ortho-NosylOXY)-Mediated Double Beckmann Rearrangement of Ketoximes under Microwave Irradiation: A Mechanistic Perception
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A method for Beckmann rearrangement using ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino) acetate (o-NosylOXY) under microwave irradiation is reported. Ketoximes (19 examples) are converted to the corresponding amides/lactams with 69–97% yields in ~10 minutes without any Lewis acid or co-catalyst. This is an example of halogen-free organocatalytic Beckmann rearrangement. Nuclear magnetic resonance (NMR)- and high-resolution mass spectrometry (HRMS)-based detailed mechanistic investigation suggest that o-NosylOXY acts as an initiator. Such initiators are reported before based on density functional theory (DFT) calculations. However, we report here the HRMS signatures of two transient intermediates, the nitrilium ion and the nitrilium ion's dimeric species. Rigorous NMR-based investigation of the reaction mechanism is performed. Our results indicate that the reported Beckmann rearrangement proceeds via two consecutive rearrangements. (Figure presented.).
- Dev, Dharm,Kalita, Tapasi,Mondal, Tanmay,Mandal, Bhubaneswar
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p. 1427 - 1435
(2021/01/04)
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- Direct Deamination of Primary Amines via Isodiazene Intermediates
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We report here a reaction that selectively deaminates primary amines and anilines under mild conditions and with remarkable functional group tolerance including a range of pharmaceutical compounds, amino acids, amino sugars, and natural products. An anomeric amide reagent is uniquely capable of facilitating the reaction through the intermediacy of an unprecedented monosubstituted isodiazene intermediate. In addition to dramatically simplifying deamination compared to existing protocols, our approach enables strategic applications of iminium and amine-directed chemistries as traceless methods. Mechanistic and computational studies support the intermedicacy of a primary isodiazene which exhibits an unexpected divergence from previously studied secondary isodiazenes, leading to cage-escaping, free radical species that engage in a chain, hydrogen-atom transfer process involving aliphatic and diazenyl radical intermediates.
- Berger, Kathleen J.,Driscoll, Julia L.,Yuan, Mingbin,Dherange, Balu D.,Gutierrez, Osvaldo,Levin, Mark D.
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supporting information
p. 17366 - 17373
(2021/11/04)
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- Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
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Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
- Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
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supporting information
p. 3011 - 3016
(2021/09/13)
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- Rapid and Mild Lactamization Using Highly Electrophilic Triphosgene in a Microflow Reactor
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Lactams are cyclic amides that are indispensable as drugs and as drug candidates. Conventional lactamization includes acid-mediated and coupling-agent-mediated approaches that suffer from narrow substrate scope, much waste, and/or high cost. Inexpensive, less-wasteful approaches mediated by highly electrophilic reagents are attractive, but there is an imminent risk of side reactions. Herein, a methods using highly electrophilic triphosgene in a microflow reactor that accomplishes rapid (0.5–10 s), mild, inexpensive, and less-wasteful lactamization are described. Methods A and B, which use N-methylmorpholine and N-methylimidazole, respectively, were developed. Various lactams and a cyclic peptide containing acid- and/or heat-labile functional groups were synthesized in good to high yields without the need for tedious purification. Undesired reactions were successfully suppressed, and the risk of handling triphosgene was minimized by the use of microflow technology.
- Fuse, Shinichiro,Komuro, Keiji,Otake, Yuma,Masui, Hisashi,Nakamura, Hiroyuki
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supporting information
p. 7525 - 7532
(2021/03/17)
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- PROCESS FOR THE PRODUCTION OF EPSILON CAPROLACTAM FROM 6- AMINOCAPROIC ACID
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The present invention refers to a new process for the production of epsilon caprolactam (CPL) from 6-aminocaproic acid (6-ACA) which can be obtained either from traditional petro chemical processes or which can be obtained from biochemical processes. With the proposed process the reaction time for conversion of 6-aminocaproic acid to the Nylon 6 monomer is shorter and significant energy savings are possible which is advantageous for industrial scale production. The conversion of 6-aminocaproic acid to the Nylon 6 monomer runs at atmospheric pressure and in the final product epsilon caprolactam with no oligomers formation of significance is obtained.
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Page/Page column 23-51
(2020/07/15)
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- Nitromethane as a nitrogen donor in Schmidt-type formation of amides and nitriles
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The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.
- Jiao, Ning,Liu, Jianzhong,Qiu, Xu,Song, Song,Wei, Jialiang,Wen, Xiaojin,Zhang, Cheng,Zhang, Ziyao
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supporting information
p. 281 - 285
(2020/01/28)
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- Beckmann rearrangement: Thiamine hydrochloride as a remarkable catalyst for one-pot synthesis of amides from ketones
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Thiamine hydrochloride catalyzed synthesis of amides from ketones including 3-acetyl coumarin via Beckmann rearrangement has been reported. The reaction is believed to involve oxime formation, cleavage of C[sbnd]C bond followed by C[sbnd]N bond formation in one-pot. Thiamine hydrochloride is stable, cheap, easy to handle and environmentally friendly.
- Mahajan, Sheena,Slathia, Nancy,Kapoor, Kamal K.
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supporting information
(2020/04/08)
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- Chlorotropylium Promoted Conversions of Oximes to Amides and Nitriles
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Chlorotropylium chloride as a catalyst for the transformations of oximes, ketones, and aldehydes to their corresponding amides and nitriles in excellent yields (up to 99 %) and in short reaction times (mostly 10–15 min). Oximes were electrophilically attacked on the hydroxyl oxygen by chlorotropylium. The produced tropylium oxime ethers were the key intermediates, of which the ketoxime ether led to amide through Beckmann rearrangement, and the aldoxime ether led to nitrile by nitrogen base DBU assisted formal dehydration. This chlorotropylium activation protocol offered general, mild, and efficient avenues bifurcately from oximes to both amides and nitriles by one organocatalyst.
- Xu, Jiaxi,Gao, Yu,Li, Zhenjiang,Liu, Jingjing,Guo, Tianfo,Zhang, Lei,Wang, Haixin,Zhang, Zhihao,Guo, Kai
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p. 311 - 315
(2020/01/25)
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- IMPROVED PROCESS FOR THE PREPARATION OF 6-AMINOHEXANOIC ACID
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The present invention relates to highly pure 6-aminohexanoic acid of formula-1 which is free of organic volatile impurities, caprolactam impurity and improved process for its preparation thereof. The present invention also relates to an improved process for the preparation of caprolactam of formula-2 which is used for the preparation of 6-aminohexanoic acid of formula-1.
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Paragraph 9-10
(2020/03/02)
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- Green synthesis method of caprolactam
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The invention discloses a green synthesis method of caprolactam. The method comprises the following steps: preparing a transition metal monatomic catalyst by adopting an illumination method; mixing atransition metal monatomic catalyst and cyclohexanone-oxime serving as a raw material according to a mass ratio of (2-10):100, putting the mixture into a vacuum reactor, performing heating to 100-150DEG C under a vacuum condition, and performing reacting for 5-10 hours; and after the reaction is finished, dissolving the reaction product with a solvent, filtering, and carrying out aftertreatment on the filtrate to obtain caprolactam. The method for preparing caprolactam has the characteristics of the simple process, mild conditions, environmental friendliness, high yield and the like.
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Paragraph 0033-0056
(2020/05/30)
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- METHOD FOR PRODUCING epsilon-CAPROLACTAM
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The present invention is a method of producing ε-caprolactam through adipamide as an intermediate, and characteristically includes a lactamization step of reacting adipamide, formed from a material compound, with hydrogen and ammonia in the presence of a catalyst containing: a metal oxide mainly containing an oxide(s) of one or more metallic elements selected from the group consisting of metallic elements of group 5 and groups 7 to 14 in the 4th to 6th periods of the periodic table; and a metal and/or a metal compound having a hydrogenation ability. The method can increase the selectivity of ε-caprolactam.
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Paragraph 0117-0122; 0127; 0134; 0135; 0140
(2020/03/09)
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- Preparation method of caprolactam
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The invention provides a preparation method of caprolactam. According to the method, lysine or alpha-amino-epsilon-caprolactam and a salt thereof and alpha-(N,N-dimethylamino)-epsilon-caprolactam anda salt thereof are used as reaction raw materials, a transition metal supported by an acidic carrier is taken as a catalyst, methanol is taken as a solvent, and one-step catalytic conversion is carried out under the conditions that the temperature is 150-300 DEG C and the hydrogen pressure is 1-12 MPa, so that the process for producing caprolactam from lysine derived from biomass and other raw materials is realized. According to the invention, the reaction process is simple, the raw materials such as lysine, alpha-amino-epsilon-caprolactam and a salt thereof and alpha-(N, N-dimethylamino)-epsilon-caprolactam and a salt thereof can be derived from biomass, and have the advantages of being environmentally friendly, renewable and the like, the supported catalyst is easy to separate, and the transition metal catalyst supported by the acidic carrier is not easy to lose in the reaction process.
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Paragraph 0033-0038; 0061-0072
(2020/06/20)
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- One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
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The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
- Coeck, Robin,De Vos, Dirk E.
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supporting information
p. 5105 - 5114
(2020/08/25)
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- TISSUE-ADHESIVE HYDROGELS
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The invention is directed to a tissue-adhesive multi-arm polymer comprising a core from which polymeric arms extent, which polymeric arms are substituted with a hydroxyl-substituted aromatic group based on compounds such as dopamine, L-DOPA, D-DOPA, tyramine, noradrenaline and/or serotonin. In addition, the invention is directed to a caprolactam blocked hydroxyl-substituted aromatic compound, suitable for the preparation of the tissue-adhesive multi-arm polymer and to the method for the preparation of the tissue-adhesive multi-arm polymer.
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Page/Page column 17-18
(2020/09/27)
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- Polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol
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A polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been developed. Good substrate compatibility, mild reaction conditions, good yields as well as the reusability of the catalyst/solvent made this procedure more environmentally benign.
- Wang, Yaoyao,Chen, Qun,He, Mingyang,Wang, Liang
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p. 210 - 214
(2018/12/04)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- Preparation method of 11-cyanoundecanoic acid
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The invention relates to a preparation method of 11-cyanoundecanoic acid. 1,1'-peroxidation dicyclohexylamine (PXA) is subjected to a self-decomposition reaction under the effect of a rare earth metalcompound and a free radical initiator, thus the 11-cyanoundecanoic acid is obtained in a high-selectivity mode, and the PXA is generated by cyclohexanone through oxyamination. According to the process line, raw materials are simple and easy to obtain, the disadvantages that an existing process is difficult to control under the high-temperature condition and low in reaction selectivity, and products are difficult to separate are avoided, and the simple and convenient method is provided for preparation of the 11-cyanoundecanoic acid.
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Paragraph 0030; 0032; 0033; 0035; 0036; 0038; 0039; 0041
(2019/05/08)
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- METHOD OF PRODUCING EPSILON-CAPROLACTAM
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A method of producing ε-caprolactam from 3-oxoadipic acid includes: step 1 of mixing at least one selected from the group consisting of 3-oxoadipic acid and salts thereof with a catalyst and a solvent in the presence of hydrogen to produce 3-hydroxyadipic acid; and step 2 of reacting the 3-hydroxyadipic acid which is a product of step 1, a salt or carboxylic acid derivative thereof, or a mixture of these with hydrogen and ammonia.
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
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p. 13080 - 13087
(2018/11/02)
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- Dichloroimidazolidinedione-Activated Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel protocol for the activation of the Beckmann rearrangement utilizing the readily available and economical geminal dichloroimidazolidinediones (DCIDs) on a substoichiometric scale (10 mol %) has been developed. A unique self-propagating mechanism for the substoichiometric dichloroimidazolidinedione-activated transformation was proposed and validated. The substrate scope of the developed protocol has been demonstrated by 23 examples with good to excellent yields (mostly 90-98%) in a short time (mostly 10-30 min), including a substrate for synthesizing the monomer of nylon-12 and a complicated steroidal substrate on a preparative scale. This research not only unveils for the first time the synthetic potential of substoichiometric amounts of dichloroimidazolidinediones in promoting chemical transformation but also offers yet another important illustration of the self-propagating cycle in the context of the Beckmann rearrangement activated by a structurally novel organic promoter.
- Gao, Yu,Liu, Jingjing,Li, Zhenjiang,Guo, Tianfo,Xu, Songquan,Zhu, Hui,Wei, Fulan,Chen, Siming,Gebru, Hailemariam,Guo, Kai
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p. 2040 - 2049
(2018/02/23)
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- Method for preparing caprolactam from cyclohexanone by one-step process
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The invention discloses a method for preparing caprolactam from cyclohexanone by one-step process. The method comprises the steps of uniformly mixing a protonic acid catalyst and cyclohexanone with amolar ratio of (0.5-10):1, adding hydroxylamine hydrochloride into the mixed solution according to a molar ratio of the hydroxylamine hydrochloride to the cyclohexanone being (1-1.5):1, and then raising the temperature to 60 to 140 DEG C under stirring to carry out a reaction, and after the reaction is completed, performing cooling crystallization to obtain the caprolactam. The method of the invention adopts polyphosphoric acid, concentrated sulfuric acid and methanesulfonic acid for catalysis and employs the one-step process for preparation of caprolactam. Compared with existing methods, thereaction steps are reduced, the process flow is greatly simplified, the cycle is shortened, the cost is reduced, and the efficiency and productivity are significantly improved.
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Paragraph 0021-0026; 0027-0033; 0034-0039; 0040-0055
(2018/05/01)
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- Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
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Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
- Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
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p. 5264 - 5271
(2018/04/24)
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- Beckmann rearrangement of ketoxime catalyzed by N-methyl-imidazolium hydrosulfate
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Beckmann rearrangement of ketoxime catalyzed by acidic ionic liquid-N-methyl-imidazolium hydrosulfate was studied. Rearrangement of benzophenone oxime gave the desirable product with 45% yield at 90 ?C. When co-catalyst P2O5 was added, the yield could be improved to 91%. The catalyst could be reused three cycles with the same efficiency. Finally, reactions of other ketoximes were also investigated.
- Hu, Hongyu,Cai, Xuting,Xu, Zhuying,Yan, Xiaoyang,Zhao, Shengxian
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- A HOST CELL MODIFIED TO PRODUCE LACTAMS
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The present invention provides for a genetically modified host cell capable of producing a lactam comprising a 2-pyrrolidone synthase, or an enzymatically active fragment thereof, heterologous to the host cell.
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Paragraph 0015; 00100
(2018/01/15)
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- Chitosan supported Zn(II) mixed ligand complexes as heterogeneous catalysts for one-pot synthesis of amides from ketones via Beckmann rearrangement
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Chitosan supported Zn(II) mixed ligand complexes have been synthesized and characterized by FT-IR, UV–Vis, TGA, XRD, FESEM, EDX, AAS and Elemental Analysis. These complexes have been found to be efficient and recyclable heterogeneous catalysts for the one-pot synthesis of amides via Beckmann rearrangement. All three complexes can be easily filtered out from the reaction medium and reused up to five times without significant loss of catalytic activity. The reported protocol is economical and novel in the sense that amides can be easily synthesized in only one-step. All products were obtained as white to off-white crystalline solids and fully characterized by 1H NMR, FT-IR and Mass Spectra.
- Anuradha,Kumari, Shweta,Layek, Samaresh,Pathak, Devendra D.
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p. 368 - 373
(2016/11/03)
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- A hydrophilic inorganic framework based on a sandwich polyoxometalate: Unusual chemoselectivity for aldehydes/ketones with in situ generated hydroxylamine
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A hydrophilic inorganic porous catalyst was prepared via the hydrothermal method. The combination of [WZn3(H2O)2(ZnW9O34)2]12- and Co(ii) provides a synergistical catalytic way to promote oximation of aldehyde/ketone with in situ generated hydroxylamine that initially produces an oxime, which further either dehydrates into a nitrile or undergoes a Beckmann rearrangement to form an amide.
- Xing, Songzhu,Han, Qiuxia,Shi, Zhuolin,Wang, Shugai,Yang, Peipei,Wu, Qiang,Li, Mingxue
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supporting information
p. 11537 - 11541
(2017/09/18)
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- Preparation method of caprolactam
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The invention discloses a preparation method of caprolactam and belongs to the technical field of chemistry and chemical engineering. A micro reaction continuous flow technology is adopted, during operation, an organic solution of cyclohexanone-oxime is used as one phase, an organic solution of 1,1-dichlorocycloheptatriene is used as the other phase, and the two phases are pumped into a micro mixer to be mixed and enter a micro reactor through a pipeline to react to synthesize caprolactam. Compared with the prior art, the method has the advantages that the reaction time is short, the method is simple and easy to control, the reaction condition is mild, the yield and the conversion rate are high and the like, and continuous production in industrial production is facilitated.
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Paragraph 0029-0032; 0033-0036; 0037-0040
(2017/10/25)
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- Method for efficiently rearranging ketoxime Beckmann by N-methyl pyrrolidone/SOC12 (thionyl chloride)
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The invention provides a method for efficiently rearranging ketoxime Beckmann by N-methyl pyrrolidone/SOC12 (thionyl chloride). The method comprises the following steps of at room temperature, reacting the N-methyl pyrrolidone and the SOC12 for 20min, adding ketoxime, continuing to react for 15min, slowly adding water, adding ethyl acetate extraction separating liquid, washing an organic layer by saturated salt water, drying by anhydrous sodium sulfate, evaporating solvent, and separating and purifying by silica-gel column chromatography, so as to obtain amide. The method has the characteristics that the technology process is simple, the reaction time is short, the reaction yield is high, and the like.
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Paragraph 0032-0034
(2017/11/21)
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- The highly efficient Beckmann rearrangement of ketoximes to amides by using Mukaiyama reagent under mild conditions
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Background: A rapid and efficient synthesis of amides via Beckmann rearrangement of ketoximes with good to excellent yields has been carried out using Mukaiyama reagent/Et3N system. The procedure is mild and suitable for both aromatic and cycloaliphatic substrates affording the products in good to quantitative yields with short reaction times. Methods: A suspension of acetophenone oxime (0.135 g, 1 mmol), Mukaiyama reagent (0.383 g, 1.5 mmol), and Et3N (0.21 mL, 1.5 mmol) in CH3CN (3 mL) was magnetically stirred at room temperature. After completion of the reaction (monitored by TLC) and evaporation of CH3CN, aqueous HCl (5%, 10 mL) was added and the organic layer extracted with CH2Cl2 (3 × 5 mL). The combined organic extracts were dried over Na2SO4, filtered, and concentrated. Purification of the crude product by short column chromatography on silica gel (n-hexane/EtOAc, 5/2) provided N-phenylacetamide (0.120 g, 89%) as a white solid: mp 112°C (lit. 113-115°C); 1H NMR (CDCl3, 250 MHz) 8.03 (brs, 1H), 7.52 (d, J=8.0 Hz, 2H), 7.28 (t, J=7.8 Hz, 2H), 7.09 (t, J=7.4 Hz, 1H), 2.15 (s, 3H). Results: In a continuation of our studies on the use of the Mukaiyama reagent in organic transformations, we became interested in evaluating it as a reagent in the presence of triethylamine as a base for the conversion of ketoximes into corresponding N-substituted amides under mild conditions. To optimize the reaction conditions and find the best base and solvent using benzophenone oxime as a model substrate, a few experiments were carried out with Mukaiyama reagent and various bases and solvents at room temperature. The optimum conditions of reaction involved benzophenone oxime (1 mmol), Mukaiyama reagent (1.5 mmol), triethylamine (1.5 mmol), CH3CN (3 mL) at room temperature. Under the optimized conditions, a series of N-substituted amides were studied to establish the scope and limitations of this method. A wide range of substituted ketoximes derived from various aromatic, cycloaliphatic, and heterocyclic ketoximes gave desired products in good to excellent yields. Conclusion: We have disclosed a mild procedure for obtaining amides from the corresponding ketoximes via Beckmann rearrangement using Mukaiyama reagent. Among the attractive features of this protocol are its use of inexpensive and commercially available reagent, mild reaction conditions, simplicity, general applicability, relatively short reaction time, high yield and good selectivity.
- Azadi, Roya,Shams, Leila
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p. 141 - 145
(2017/03/30)
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- METHOD FOR PREPARING CAPROLACTAM BY USING A MICROREACTOR UNDER LEWIS ACID CATALYSIS
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A method for preparing caprolactam by using a microreactor under Lewis acid catalysis, wherein a hydroxyl group in a cyclohexanone oxime is activated to obtain a cyclohexanone oxime sulfonates intermediate, then rearranged under Lewis acid catalysis to prepare the caprolactam. The method of this invention has a simple process and a high operation safety and selectivity, the reaction condition is mild, an efficient reaction can take place even at room temperature, the reaction time is short, the conversion of the cyclohexanone oxime can reach 100% within a short time, the selectivity of the caprolactam can reach 99%, the energy consumption is greatly reduced in the premise of maintaining a high yield, and the production cost is reduced, being an efficient and green and environmentally friendly method of for synthesizing the caprolactam.
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Paragraph 0044
(2017/01/26)
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- A process for the preparation of caprolactam
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The invention discloses a method for preparing caprolactam. The method comprises the following steps: slowly adding a sulfuric acid solution into a cyclohexane and sodium nitrite mixed solution, carrying out a nitrosation reaction to obtain an nitrosocyclohexane intermediate and a solid salt; and filtering to separate out the solid salt, adding a catalyst to the obtained remaining filtrate, supplementing the sulfuric acid solution to carry out a rearrangement reaction, and distilling after the rearrangement reaction to recover cyclohexane in order to obtain a mixed liquid containing caprolactam. The method adopts cyclohexane and sodium nitrite as raw materials to produce caprolactam under mild reaction conditions in a high selectivity manner, so the method has the advantages of mild reaction conditions, low device requirement and low production cost, and can meet industrial production requirements.
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Paragraph 0029; 0030; 0031; 0032; 0033; 0034; 0035-0047
(2017/04/20)
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- A new route to N-aromatic heterocycles from the hydrogenation of diesters in the presence of anilines
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The hydrogenation of dicarboxylic acids and their esters in the presence of anilines provides a new synthesis of heterocycles. [Ru(acac)3] and 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos) gave good to excellent yields of the cyclic amines at 220 °C. When aqueous ammonia was used with dimethyl 1,6-hexadienoic acid, ?-caprolactam was obtained in good yield. A side reaction involving alkylation of the amine by methanol was suppressed by using diesters derived from longer chain and branched alcohols. Hydrogenation of optically pure diesters (dimethyl (R)-2-methylbutanedioate and dimethyl (S)-2-methylbutanedioate) with aniline afforded racemic 3-methyl-1-phenylpyrrolidine in 78% yield.
- Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.,Harvie, Michelle,Baxter, Emma F.,Lim, Kate J. C.,Pogorzelec, Peter
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p. 6911 - 6917
(2017/10/05)
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- One-pot conversion of cyclohexanol to ?-caprolactam using a multifunctional Na2WO4-acidic ionic liquid catalytic system
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Na2WO4-acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one-pot conversion of cyclohexanol to ?-caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid-functionalized ionic liquids with HSO4?as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase-transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate during the oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.
- Wang, Hefang,Jia, Liyuan,Hu, Rongbin,Gao, Meidan,Wang, Yanji
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- Strong influence of intramolecular Si?O proximity on reactivity: Systematic molecular structure, solvolysis, and mechanistic study of cyclic N-trimethylsilyl carboxamide derivatives
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A comparative alcoholysis study of N-silylated derivatives of simple heterocyclic carboxamides (lactams, imides, ureas) is presented. The second-order rate constant values span a range as wide as three orders of magnitude. On the basis of DFT calculations, a good correlation between reactivity and the Si?O distance was found within each family of compounds. The viability of two different reaction pathways was evaluated using a detailed computational mechanistic study of the methanolysis of cyclic urea homologues. Peculiarities in the single-crystal X-ray diffraction structures of the trimethylsilyl and trimethylsiloxy phthalimides are also discussed.
- Szalay, Roland,Harmat, Veronika,E?ri, János,Pongor, Gábor
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p. 2186 - 2192
(2017/05/16)
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- Phosphovanadomolybdic acid catalyzed desulfurization-oxygenation of secondary and tertiary thioamides into amides using molecular oxygen as the terminal oxidant
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In the presence of phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, desulfurization-oxygenation of various kinds of structurally diverse secondary and tertiary thioamides proceeded efficiently using molecular oxygen as the terminal oxidant, affording the corresponding amides in moderate to excellent yields. In addition, 18O-labeled amides could readily be synthesized using H218O as the oxygen source.
- Xu, Ning,Jin, Xiongjie,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 4865 - 4869
(2016/07/06)
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- Caprolactam and manufacturing method thereof
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PROBLEM TO BE SOLVED: To provide ε-caprolactam in which the content of 7-methyl-ε-caprolactam is 0.025 mass% or less, preferably 0.020 mass% or less and further the content of 3-methyl-ε-caprolactam is 0.004 mass% or less, preferably 0.003 mass%, and to provide a method for producing the same.SOLUTION: There are provided ε-caprolactam synthesized via 6-amino-2-chlorocaproic acid and 6-aminocaproic acid using lysine and/or a salt of lysine as a raw material and a method for producing the same.
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Paragraph 0060
(2017/06/21)
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- Efficient one-stage procedure of Beckmann ketones rearrangement in the presence of hydroxylamine
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Ketoximes formed from ketones in the presence of hydroxylamine and silica gel in formic acid undergo in situ the Beckmann rearrangement under mild conditions affording in high yields the corresponding amides. Unsymmetrical aromatic ketones, methyl aryl ketones, and methyl cyclohexyl ketone under these conditions form as a rule amides mixtures.
- Kuksenok,Shtrykova,Filimonov,Sidel'nikova
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p. 196 - 199
(2016/04/19)
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- A directly to the method of synthesis of caprolactam
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The invention relates to a method for directly synthesizing caprolactam from cyclohexanone serving as a raw material. The method comprises the following steps of adding cyclohexanone, an ionic liquid type hydroxylamine salt and a zinc salt catalyst into a reactor, adding a solvent, stirring, carrying out reflux condensing, and reacting for 1-5 hours at normal pressure and the temperature of 50-90 DEG C, thereby obtaining the product caprolactam, wherein the ionic liquid type hydroxylamine salt is a 1-sulfobutyl-3-methylimidazolium bisulfate ionic liquid type hydroxylamine salt. The method has the advantages that the integration of two step reactions, namely the synthesis of cyclohexanone oxime from cyclohexanone and hydroxylamine and the preparation of caprolactam through cyclohexanone oxime rearrangement, is realized in the same reactor, so that the reaction process flow is shortened, and the equipment investment is reduced; the reaction conditions are mild; low-value ammonium sulfate is not by-produced; and the conversion ratio of cyclohexanone and the selectivity of caprolactam are very high and can reach 82.7% and 97.5% to the highest.
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Paragraph 0025; 0026; 0039; 0040
(2016/12/01)
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- A cyclohexanone and ion liquid type hydroxylamine salt the one-step method of synthesis of caprolactam
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The invention relates to a method of directly synthesizing hexanolactam by cyclohexanone and ionic liquid type hydroxylamine salt. The method comprises the following steps: adding cyclohexanone, ionic liquid type hydroxylamine salt and a zinc salt catalyst into a reactor and uniformly stirring at room temperature; and then, carrying out a reaction at 140-160 DEG C for 0.5-2.5 hours in a closed system to obtain the product hexanolactam, wherein the material molar ratio of cyclohexanone to ionic liquid type hydroxylamine salt to zinc salt catalyst is 1 to (1-2) to (1.5-3), and the ionic liquid type hydroxylamine salt is 1-sulfobutyl-3-methylimidazole hydrosulfate ionic liquid type hydroxylamine salt. The method provided by the invention integrates oximation of cyclohexanone and rearrangement of cyclohexanone-oxime in a same reactor, so that the reaction flow is shortened and the production cost of hexanolactam is remarkably saved. The method has the advantages of no corrosion to equipment, environment-friendliness and the like and meets the requirements on green chemistry. The conversion ratio of cyclohexanone and the selectivity of hexanolactam are high, and the maximum can be up to 100% and 91.0% respectively.
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Paragraph 0029; 0030
(2017/02/24)
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