Synthesis Of Caprolactam Research Articles

Thermal decomposition behavior, thermal stability and thermal explosion risk evaluation of a novel green hydroxylamine ionic liquid salt

Hydroxylamine salts are important chemical raw materials to a wide range of applications ranging from the synthesis of caprolactam, to pesticides and medicine. However, challenging setbacks associated with environmental pollution, equipment corrosion and explosive safety hazards are inevitably encountered with traditional hydroxylamine salts due to the release of strong acids and their poor thermal stability. In order to address those mentioned above environmental and safety challenges, an acidic ionic liquid, instead of inorganic acids, was introduced to stabilize hydroxylamine. Hence, a novel green chemical-hydroxylamine 1-sulfobutyl-3-methyl imidazole hydrosulfate salt ((NH2OH)2·[HSO3-b-mim]·HSO4) was created. It is essential to systematically study thermal decomposition behavior, thermal stability and safety of the novel hydroxylamine ionic liquid salt. This study used the thermogravimetric method to investigate the thermal decomposition process of (NH2OH)2·[HSO3-b-mim]·HSO4. The mechanism of thermal decomposition function and kinetic model were obtained by the Coats-Redfern method. The thermal explosion risk of (NH2OH)2·[HSO3-b-mim]·HSO4 under adiabatic conditions was evaluated using a differential scanning calorimeter (DSC) and an accelerated adiabatic calorimeter (ARC). The results indicate that (NH2OH)2·[HSO3-b-mim]·HSO4 exhibits good thermal stability and safety, providing an avenue for the future production, storage and application of this eco-friendly hydroxylamine product.

Trifluoroacetic Acid Hydroxylamine System as Organocatalyst Reagent in a One-Pot Salt Free Process for the Synthesis of Caprolactam and Amides of Industrial Interest

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 abstractSalt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent.

Caprolactam Synthesis using Ce-MCM-41Catalysts

Siliceous MCM-41 was synthesized by hydrothermal method using sodiummetasilicate as a source. Cerium ion incorporated Si-MCM-41 was synthesized by hydrothermal method using Cetyltrimethylammonium bromide as template. 2, 3 and 4 weight percentage of Ceria was loaded over MCM-41 by wet impregnation method. The synthesized catalysts were characterized using FT-IR, DRS-UV-Vis, XRD and SEM techniques. The catalytic activity of the cerium ion incorporated and ceria impregnated MCM-41 was evaluated in the synthesis of caprolactam from cyclohexanone oxime in the liquid phase condition. At high temperature all the catalyst showed high conversion. In that 4 wt.% Ce impregnated Si-MCM-41 produced high conversion (76.2%) and percentage yield (66.4%). The impregnated catalyst may contain more number of cerium present in the pores, so the lewis acid sites will be more and the conversion of cyclohexanone oxime into caprolactam will be high.

Zr mesoporous molecular sieves as novel solid acid catalysts in synthesizing nitrile and caprolactam.

Zr mesoporous materials with different Si/Zr ratio were synthesized by the surfactant-templated method involving cetyl trimethyl ammonium bromide (CTAB) as template and tetraethyl ortho silicate (TEOS) as organic source of silicon. The synthesized materials were labeled as SiZrMx (where x is Si/Zr = 10, 20 and 30). The BET analysis showed bimodal distribution of pores in SiZrMx structure. An attempt was made to generate super acidity on SiZrM20 by sulfation using sulfuric acid and ammonium sulfate (wt% = 4, 8 and 12). The NH3-TPD results revealed the presence of strong acidity in sulfated Zr-MCM-41. To understand the nature of acidity in Sulfated Zr-MCM-41, the efficiency of the materials is investigated in dehydration of Oximes. The industrially important materials caprolactam and intermediate nitrile were synthesized from their oximes in liquid phase system. Due to strong acidity in sulfated Zr-MCM-41, fast deactivation was observed during the synthesis of caprolactam but, the catalyst showed 96% nitrile selectivity. The strong acidity and medium strong acidity favoured the formation of nitrile and caprolactam respectively. This study revealed the molecular sieves were effective and eco-friendly solid acid catalysts for synthesizing caprolactam and nitrile.

Titanium Containing Solid Core Mesoporous Silica Shell: A Novel Efficient Catalyst for Ammoxidation Reactions

Novel titanium containing solid core mesoporous shell silica has been synthesized by using octadecyltrichloro silane and triethylamine. The synthesized material was characterized by various physicochemical techniques. The mesoporous character of the material has been revealed from PXRD studies. The presence of octadecyltrichloro silane and triethylamine in the sample has been confirmed from EDAX studies. TG/DTA analysis reveals the thermal characteristics of the synthesized material. The presence of titanium in the frame work and its coordination state has been studies by UV-vis DR studies and XPS analysis. Chemical environment of Si in the framework of the material has been studied by 29 SiMASNMR studies. The surface area of the material is found to be around 550 m 2 g �1 and pore radius is of nano range from BET analysis. The spherical morphology and particle size of the core as well as shell has been found to be 300 nm and 50 nm respectively from TEM analysis. The catalytic application of this material towards the synthesis of caprolactam from cyclohexanone in presence of hydrogen peroxide through ammoxidation reaction has been investigated. The optimum conditions for the reaction have been established. The plausible mechanism for the formation of core silica and conversion of cyclohexanone has been proposed.

The continuous synthesis of ε-caprolactam from 6-aminocapronitrile in high-temperature water

Caprolactam (CPL) is a widely used chemical intermediate for the production of Nylon-6. However, existing synthetic routes in industry have severe drawbacks. The development on the synthesis of CPL from 6-aminocapronitrile (ACN), using near- and supercritical water as the solvent, reactant and catalyst, is described in this paper. The two-step reaction (hydrolysis and cyclization) to produce CPL is combined in a single process, by using a continuous-flow system. Effects of pressure, temperature, residence time and the concentration of ACN were studied. The high-temperature high-pressure environment possesses unique properties which result in very efficient catalysis. The overall CPL yield reaches 90% within a short residence time (<2 min).

Modifications in the synthesis of caprolactam and nylon 6

Modifications in the synthesis of caprolactam and nylon 6

Synthesis of caprolactam and Nylon 6

ADVERTISEMENT RETURN TO ISSUEPREVLab-ExptNEXTSynthesis of caprolactam and Nylon 6Charles E. Carraher Jr.Cite this: J. Chem. Educ. 1978, 55, 1, 51Publication Date (Print):January 1, 1978Publication History Received3 August 2009Published online1 January 1978Published inissue 1 January 1978https://doi.org/10.1021/ed055p51RIGHTS & PERMISSIONSArticle Views2957Altmetric-Citations12LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Central nervous system active compounds. II. The synthesis of some 4-, 5-, 6- and 7-substituted caprolactams

The synthesis of caprolactam derivatives substituted at C4, C5, C6 and C7 with alkyl, aryl, acyl and hetero substituents is described. A variety of synthetic approaches to these compounds have been investigated and assessed, particularly for the synthesis of C4- and C6-substituted compounds. A significant number of the C4-, C6- and C7- substituted compounds prepared show central nervous system activity, ranging from convulsants to depressants depending on the position and nature of the substituent group.