Academic literature on the topic 'Conversion cyclopentanol/cyclohexanone'

Arylazoimidazole brings azoimine (-N=N-C=N-) chelating N(azo), N(imine) (abbreviated - N, N/) centres and forms Ru(II) and Os(II) carbonyl complexes. These complexes act as catalysts for the oxidation of alcohols to aldehydes/ketones by tertiary butyl hydro peroxide (ButOOH), hydrogen peroxide (H2O2) and N-methylmorpholine-N-oxide (NMO) as oxygen sources. Different substituted arylazoimidazoles such as 1-alkyl-2-(arylazo)imidazoles (RaaiR/), 1-alkyl-2-(naphthyl-α/β- azo)imidazoles (α/β-NaiR) and (1-alkyl-2-{(o-thioalkyl)phenylazo}imidazole, SRaaiNR/) are used to prepare Ru/Os-CO complexes. Ancillary ligands like hydride (H-), chloride (Cl-), triphenylphosphine (PPh3) are used to monitor the catalytic efficiency of the complexes. Aromatic and aliphatic alcohols like benzyl alcohol, 2-butanol, cyclopentanol, cyclohexanol, 1-phenylethanol, cinnamyl alcohol, diphenylmethanol, are oxidized to the corresponding benzaldehyde, 2-butanone, cyclopentanone, cyclohexanone, phenylacetone, cinamaldehyde, cyclopentanone, benzophenone, respectively. Different physicochemical analyses (FT-IR, UV-Vis, Mass, NMR) suggest that the complexes react with an oxidant to yield high valent ruthenium/osmium-oxo species (RuIV=O; OsIV=O), which is capable of transferring the oxygen atom to alcohols. GC analysis accounts that percentage conversion order is as follows : Cinnamyl alcohol > Cyclohexanol ~ 1-Phenylethanol > Diphenylmethanol > Cyclopentanol > 2-Butanol > Benzyl alcohol. The oxidation efficiency of the oxidant follows the order : NMO > ButOOH > H2O2. RuII complexes are more potent catalysts than OsII complexes. Out of three series of RuII complexes, [RuCl(CO)(SMeaaiNEt)]ClO4 and [RuCl(CO)(SEtaaiNMe)]ClO4 showed highest catalytic efficiency amongst 32 catalysts.

ABSTRACT Cyclopentanone 1,2-monooxygenase, a flavoprotein produced by Pseudomonas sp. strain NCIMB 9872 upon induction by cyclopentanol or cyclopentanone (M. Griffin and P. W. Trudgill, Biochem. J. 129:595-603, 1972), has been utilized as a biocatalyst in Baeyer-Villiger oxidations. To further explore this biocatalytic potential and to discover new genes, we have cloned and sequenced a 16-kb chromosomal locus of strain 9872 that is herein reclassified as belonging to the genus Comamonas. Sequence analysis revealed a cluster of genes and six potential open reading frames designated and grouped in at least four possible transcriptional units as (orf11-orf10-orf9)-(cpnE-cpnD-orf6-cpnC)-(cpnR-cpnB-cpnA)-(orf3-orf4 [partial 3′ end]). The cpnABCDE genes encode enzymes for the five-step conversion of cyclopentanol to glutaric acid catalyzed by cyclopentanol dehydrogenase, cyclopentanone 1,2-monooxygenase, a ring-opening 5-valerolactone hydrolase, 5-hydroxyvalerate dehydrogenase, and 5-oxovalerate dehydrogenase, respectively. Inactivation of cpnB by using a lacZ-Kmr cassette resulted in a strain that was not capable of growth on cyclopentanol or cyclopentanone as a sole carbon and energy source. The presence of σ54-dependent regulatory elements in front of the divergently transcribed cpnB and cpnC genes supports the notion that cpnR is a regulatory gene of the NtrC type. Knowledge of the nucleotide sequence of the cpn genes was used to construct isopropyl-β-thio-d-galactoside-inducible clones of Escherichia coli cells that overproduce the five enzymes of the cpn pathway. The substrate specificities of CpnA and CpnB were studied in particular to evaluate the potential of these enzymes and establish the latter recombinant strain as a bioreagent for Baeyer-Villiger oxidations. Although frequently nonenantioselective, cyclopentanone 1,2-monooxygenase was found to exhibit a broader substrate range than the related cyclohexanone 1,2-monooxygenase from Acinetobacter sp. strain NCIMB 9871. However, in a few cases opposite enantioselectivity was observed between the two biocatalysts.

Abstract This paper reports cyclopentane, cyclohexane and cyclooctane oxidation in the presence of N-hydroxyphthalimide or 4-dodecyloxycarbonyl-N-hydroxyphthalimide in combination with Co(II) and Fe(II) salts using O2/CO2 mixture (0.5 MPa O2, 9.5 MPa CO2). The studies demonstrated that the application of scCO2 in cyclohexane and cyclooctane oxidation processes results in higher conversion and yield of respective ketone and alcohol in comparison to processes performed using air under pressure (0.7 MPa).

The catalytic oxidation of cycloalkanes using molecular oxygen employing porphyrin cobalt(II) as catalyst was enhanced through use of cycloalkyl hydroperoxides, which are the primary intermediates in oxidation of cycloalkanes, as additional oxidants to further oxidize cycloalkanes in the presence of porphyrin copper(II), especially for cyclohexane, for which the selectivity was enhanced from 88.6 to 97.2% to the KA oil; at the same time, the conversion of cyclohexane was enhanced from 3.88 to 4.41%. The enhanced efficiency and selectivity were mainly attributed to the avoided autoxidation of cycloalkanes and efficient utilization of oxidation intermediate cycloalkyl hydroperoxides as additional oxidants instead of conventional thermal decomposition. In addition to cyclohexane, the protocol presented in this research is also very applicable in the oxidation of other cycloalkanes such as cyclooctane, cycloheptane and cyclopentane, and can serve as a applicable and efficient strategy to boost the conversion and selectivity simultaneously in oxidation of alkanes. This work also is a very important reference for the extensive application of metalloporphyrins in catalysis chemistry.

A useful annulation method leading to the stereospecific synthesis of structurally novel, functionalized bicyclic dienes is described. Alkylation of 2-(methoxycarbonyl)cyclopentanone (34) and 2-(methoxycarbonyl)cyclohexanone (35) with methyl (E)- and (Z)-6-iodo-3-trimethylstannyl-2-hexenoates (27, 28) provided the keto diesters 36–39. Conversion of these substances into the corresponding enol triflates 47–50, followed by palladium(0)-catalyzed ring closure of the latter compounds, afforded the bicyclic dienes 55–58. In similar fashion, the keto esters 34 or 35 were transformed into the dienes 59–65. An X-ray crystallographic analysis of the p-nitrobenzoate 69, which was derived from the cisoidcis diene 64, showed that, in 69, the dihedral angle between the two carbon–carbon double bonds is −54.0(5)°.

The present work focuses on the techno-economic assessment and multi-objective genetic algorithm optimization of small-scale (40 kWth input), solar Organic Rankine Cycle (ORC) systems driven by medium-to-high temperature (up to 210 °C) parabolic dish (PDC) and trough (PTC) collectors. The ORCs are designed to maximize their nominal thermal efficiency for several natural hydrocarbon working fluids. The optimization variables are the solar field area and storage tank capacity, with the goal of minimizing the levelized cost of produced electricity (LCoE) and maximizing the annual solar conversion efficiency. The lowest LCOE (0.34 €/kWh) was obtained in Athens for a high solar field area and low storage tank capacity. Meanwhile, the maximum annual solar conversion efficiencies (10.5–11%) were obtained in northern cities (e.g., Brussels) at lower solar field locations. While PTCs and PDCs result in similar efficiencies, the use of PTCs is more cost-effective. Among the working fluids, Cyclopentane and Cyclohexane exhibited the best performance, owing to their high critical temperatures. Notably, the systems could be more profitable at higher system sizes, as indicated by the 6% LCoE decrease of the solar ORC in Athens when the nominal heat input was increased to 80 kWth.

The kinetics of the direct chlorination of cyclopentanone (cp) and cyclohexanone (ch) in carbon tetrachloride, catalyzed by hydrogen chloride, was studied. The rate of chlorination, measured by flow and stopped-flow techniques, is zero order in chlorine; the order in cp and ch increases from 1 at [cp] and [ch] of 0.01 M concentration to 2 at concentrations of 1 M. This is explained by self-association of the ketones in carbon tetrachloride solutions. The order in hydrogen chloride is 1. Since this compound is one of the products, the reaction is autocatalytic. Deuterium isotope effects and the kinetic data strongly point to a mechanism in which the oxygen-protonated monomeric ketone is α-carbon deprotonated in a rate-determining step. This step, which is catalyzed by the bases cp or ch, respectively, leads to the corresponding enol as intermediate. The enol is then chlorinated very rapidly. In addition to the chloro ketone, very reactive chloride anions are formed. A small fraction of these anions deprotonate α- or α′-carbon atoms of the oxygen-conjugate acid of the monochloro ketone. The remainder are captured by HCl to form energetically more favored Cl--(HCl)n complexes with n = 1, 2, or 3. This explains why, even at low conversions of the ketones, substantial amounts of the various dichloro isomers are formed in addition to monochloro products. A rate expression is derived, which excellently describes the experimentally obtained rates of chlorination of cp and ch over a range of reaction rates of more than three decades.

La conception de solides à la fois stables en conditions hydrothermales, mais aussi capables de convertir des composés biosourcés en molécules plateformes dans un même lit catalytique, représente un défi majeur en science des matériaux.Dans ce contexte, des oxydes mixtes binaires et ternaires de silice dopée avec les éléments W, Ti, Zr, Nb, Ta et Mg (3 à 20%at.) ont été élaborés via la méthode non conventionnelle de synthèse Sol-Gel Non Hydrolytique (SGNH). Cette méthode permet d’obtenir des oxydes mixtes très homogènes et de moduler finement leurs propriétés via les paramètres de synthèse.Les solides sont majoritairement amorphes et mésoporeux. Les analyses en MET-EDS, FTIR et ToF-SIMS indiquent que les éléments dopants sont bien dispersés dans la silice et que les oxydes mixtes présentent majoritairement une homogénéité allant jusqu’à l’échelle nanométrique voire atomique.Les molécules sondes NH3 et CO révèlent la présence des sites acides de forces faible et moyenne, majoritairement de type Lewis pour l’ensemble des matériaux. La densité de sites acides peut être promue via : l’amélioration du degré d’homogénéité entre les oxydes, l’élaboration d’oxydes mixtes ternaires et l’augmentation de la teneur en éléments dopants.La caractérisation des solides par la réaction modèle de conversion du mélange cyclopentanol/cyclohexanone en phase gaz montre que la majorité des matériaux catalysent à la fois des réactions de déshydratation et de transfert d’hydrogène (réduction MPVO).Après traitement hydrothermal en phase gaz à 400°C, les solides conservent de bonnes textures, en particulier les oxydes mixtes ternaires et dopés à haute teneur.Cette étude montre la versatilité de la méthode de synthèse SGNH et son potentiel pour mettre au point des oxydes mixtes binaires et ternaires très homogènes. Les oxydes mixtes ternaires, contenant 20% d’éléments dopants et contenant du Nb, du Zr ou du Ta sont particulièrement prometteurs pour les applications visées
The design of new heterogeneous catalysts with good hydrothermal stability that are able to transform bio-based components into building blocks in one single catalytic process is a main challenge in material science.In this context, binary and ternary mixed oxides of silica doped with W, Ti, Zr, Nb, Ta et Mg (3 to 20%at.) have been produced with the non-conventional Non-Hydrolytic Sol-Gel (NHSG) synthesis method. This method enables to obtain highly homogeneous mixed oxides and to finely shape the properties of the material with the synthesis parameters.The solids are mostly amorphous and mesoporous. TEM-EDS, FTIR and ToF-SIMS analysis indicate that the doping elements are highly dispersed in the silica and that most of the mixed oxides display nanometric or atomic scale homogeneity.The NH3 and CO bases show the presence of mostly Lewis weak and medium strength acid sites for these materials. The acid sites density can be improved through: increasing mixed oxide homogeneity, preparing ternary mixed oxides, increasing doping element content.The conversion of the mixture cyclopentanol/cyclohexanone in the gas phase shows that the majority of the materials perform both dehydration and hydrogen transfer reactions (MPVO reduction).After steaming at 400°C, the solids maintain good textures, particularly ternary mixed oxides and mixed oxides containing high dopant content.This study shows the versatility of the NHSG synthesis method and its applicability in order to design binary and ternary mixed oxides. The ternary mixed oxides containing 20%at. of doping elements with Nb, Zr and Ta are promising for the conversion of bio-based compounds

Varinder K. Aggarwal of the University of Bristol described (Angew. Chem. Int. Ed. 2010, 49, 6673) the conversion of the Sharpless-derived epoxide 1 into the cyclopropane 2. Christopher D. Bray of Queen Mary University of London established (Chem. Commun. 2010, 46, 5867) that the related conversion of 3 to 5 proceeded with high diastereocontrol. Javier Read de Alaniz of the University of California, Santa Barbara, extended (Angew. Chem. Int. Ed. 2010, 49, 9484) the Piancatelli rearrangement of a furyl carbinol 6 to allow inclusion of an amine 7, to give 8. Issa Yavari of Tarbiat Modares University described (Synlett 2010, 2293) the dimerization of 9 with an amine to give 10. Jeremy E. Wulff of the University of Victoria condensed (J. Org. Chem. 2010, 75, 6312) the dienone 11 with the commercial butadiene sulfone 12 to give the highly substituted cyclopentane 13. Robert M. Williams of Colorado State University showed (Tetrahedron Lett. 2010, 51, 6557) that the condensation of 14 with formaldehyde delivered the cyclopentanone 15 with high diastereocontrol. D. Srinivasa Reddy of Advinus Therapeutics devised (Tetrahedron Lett. 2010, 51, 5291) conditions for the tandem conjugate addition/intramolecular alkylation conversion of 16 to 17. Marie E. Krafft of Florida State University reported (Synlett 2010, 2583) a related intramolecular alkylation protocol. Takao Ikariya of the Tokyo Institute of Technology effected (J. Am. Chem. Soc. 2010, 132, 11414) the enantioselective Ru-mediated hydrogenation of bicyclic imides such as 18. This transformation worked equally well for three-, four-, five-, six-, and seven-membered rings. Stefan France of the Georgia Institute of Technology developed (Org. Lett. 2010, 12, 5684) a catalytic protocol for the homo-Nazarov rearrangement of the doubly activated cyclopropane 20 to the cyclohexanone 21. Richard P. Hsung of the University of Wisconsin effected (Org. Lett. 2010, 12, 5768) the highly diastereoselective rearrangement of the triene 22 to the cyclohexadiene 23. Strategies for polycyclic construction are also important. Sylvain Canesi of the Université de Québec devised (Org. Lett. 2010, 12, 4368) the oxidative cyclization of 24 to 25.

Zachary T. Ball of Rice University found (Chem. Sci. 2014, 5, 1401) that the on-bead performance of a designed Rh- peptide complex was markedly superior to the corre­sponding solution catalysis for the addition of 2 to 1 to give 3. Jin-Quan Yu of Scripps/La Jolla achieved (J. Am. Chem. Soc. 2014, 136, 8138) remarkable ee in the conversion of 4 to 5. Adriaan J. Minnaard of the University of Groningen developed (Adv. Synth. Catal. 2014, 356, 2061) practical conditions for enantioselective conjugate addi­tion– enolate trapping, converting 6 to 8. Alexandre Alexakis of the University of Geneva had reported (Org. Lett. 2014, 16, 118) related results. Jérôme Waser of the Ecole Polytechnique Fédérale de Lausanne assembled (J. Am. Chem. Soc. 2014, 136, 6239) the amino cyclopentane 11 by adding 9 to 10. Jean-Luc Vasse of the Université de Reims used (Org. Lett. 2014, 16, 1506) the Schwartz reagent to cyclize 12 to 13. Eric V. Johnston and Armando Córdova of the University of Stockholm combined (Angew. Chem. Int. Ed. 2014, 53, 3447) Pd and organocatalysis in a cascade of first oxi­dation of 14, then conjugate addition by 15, then cyclization to 16. Professor Alexakis found (Org. Lett. 2014, 16, 2006) that the enolate from con­jugate addition to 17 could be trapped with a nitroalkene 18 to give, after in situ Nef reaction, the 1,4-diketone 19. Fangzhi Peng and Zhihui Shao of Yunnan University added (Chem. Eur. J. 2014, 20, 6112) malonate to the nitro alkene 20 to give an inter­mediate that could be carried to the cyclohexanone 21. Masahisa Nakada of Waseda University devised (Tetrahedron Lett. 2014, 55, 1100) a cascade conjugate reduc­tion—intramolecular conjugate addition to cyclize 22 to 23. Hye-Young Jang of Ajou University dimerized (Synthesis 2014, 46, 1329) cinnamaldehyde 24 with nitrometh­ane to give the fully-substituted cyclohexanol 25. In a remarkable cascade transformation, Joëlle Prunet of the University of Glasgow used (Org. Lett. 2014, 16, 3300) the Zhang Ru catalyst to cyclize 26 to the taxol skeleton 27. In an even more remarkable transformation, Professor Nakada showed (Tetrahedron Lett. 2014, 55, 1597) that cascade conjugate addition– conjugate addition converted 28 to 29, having the rare chair- boat- chair skeleton of the biologically potent fusidic acid and brasilicardin A.