Showing papers on "Cyclohexanone published in 1989"
TL;DR: In this article, the oxidation of liquid cyclohexane by O2 over UV-illuminated TiO2 at room temperature has been studied in a static slurry reactor.
Abstract: The oxidation of liquid cyclohexane by O2 over UV-illuminated TiO2 at room temperature has been studied in a static slurry reactor. From the effects of the mass of catalyst, the temperature, the radiant flux, the concentration of C6H12 (using acetonitrile as a solvent), it is concluded that the reaction is photocatalytic. Using mainly the 365 nm-ray of a mercury-lamp, an initial quantum yield of 0.1 is found for pure cyclohexane and radiant fluxes < ca.5mWcm−2 (6×1015 photons s−1 cm−2). A high selectivity to cyclohexanone is observed (83%), the other products being cyclohexanol (5%) and CO2 (12%). The low amount of cyclohexanol is explained by the higher rate of oxidation of this alcohol compared to that of cyclohexane. Smaller oxidation rates are observed when TiO2 is loaded with 0.5 to 10 wt%Pt and the cyclohexanone/cyclohexanol ratio decreases to ca. 4. Finally, the C6H12 oxidation has been employed as a test reaction to confirm the detrimental effect of the doping with several tri or pentavalent cations upon the photocatalytic activity of TiO2.
209 citations
TL;DR: In this article, the authors show that the residual free silanol groups of the matrix in the matrix can be used as a useful insoluble catalyst for the Knoevenagel condensation.
Abstract: Silica gel functionalized with amino groups is a useful insoluble catalyst for the Knoevenagel condensation: the reaction can be carried out under continuous-flow conditions and good yields are obtained when aromatic aldehydes, cyclohexanone, and acetophenone react with ethyl acetoacetate, ethyl cyanoacetate, and malononitrile. Lower yields are obtained in the case of ethyl benzoylacetate and acetylacetone; this fact and the easy dehydration of the aldol intermediate strongly suggest the participation of the residual free silanol groups of the matrix in the catalysis mechanism.
133 citations
TL;DR: Carbonyl compds are readily acetalized under mild conditions in the presence of catalytic amts of Rh(III)-MeC(CH2PPh2)3 complexes as mentioned in this paper.
89 citations
TL;DR: Indium(I) iodide was found to mediate in the Barbier allylation and in the Reformatsky reaction of aldehydes and ketones to give homoallylic alcohols and β-hydroxy esters, respectively, presumably via allylindium(III) diiodide as discussed by the authors.
68 citations
TL;DR: The enzymes involved in the anaerobic degration of cyclohexanol were searched for in a denitrifying Pseudomonas species which metabolizes this alicyclic compound to CO2 anaerobically.
Abstract: The enzymes involved in the anaerobic degradation of cyclohexanol were searched for in a denitrifying Pseudomonas species which metabolizes this alicyclic compound to CO2 anaerobically. All postulated enzyme activities were demonstrated in vitro with sufficient specific activities. Cyclohexanol dehydrogenase catalyzes the oxidation of the substrate to cyclohexanone. Cyclohexanone dehydrogenase oxidizes cyclohexanone to 2-cyclohexenone. 2-Cyclohexenone hydratase and 3-hydroxycyclohexanone dehydrogenase convert 2-cyclohexenone via 3-hydroxycyclohexanone into 1,3-cyclohexanedione. Finally, the dione is cleaved by 1,3-cyclohexanedione hydrolase into 5-oxocaproic acid. Some kinetic and regulatory properties of these enzymes were studied.
62 citations
34 citations
Patent•
17 Jan 1989
TL;DR: In this paper, the maximum azeotrope of formic acid is removed from mixtures containing it and water by using extractive distillation in a mixture of cyclohexanone, isophorone and diisobutyl ketone.
Abstract: Formic acid cannot be completely removed from formic acid--water mixtures by distillation because of the presence of the maximum azeotrope. Formic acid can be readily removed from mixtures containing it and water by using extractive distillation in which the extractive distillation agent is cyclohexanone, isophorone or a mixture of these with certain organic compounds. Typical examples of effective agents are cyclohexanone; isophorone; cyclohexanone and neodecanoic acid; isophorone and diisobutyl ketone.
29 citations
TL;DR: In this article, aldol addition reactions of the lithium enolate of cyclohexanone with aromatic aldehydes showed high kinetic threo selectivity, and they were shown to have high kinetic selectivity.
29 citations
TL;DR: In this article, the intefacial polycondensation of 2,6-bis(4-hydroxy-3methoxybenzylidene)- cyclohexanone with 4,4'-diphenic, isophthalolyl, terephthaloyl, adipoyl and sebacoyl dichlorides have been produced.
Abstract: New polyesters prepared by the intefacial polycondensation of 2,6-bis(4- hydroxybenzylidene )cyclohexanone (I) and 2,6-bis(4-hydroxy-3-methoxybenzylidene)- cyclohexanone (II) with 4,4'-diphenic, isophthalolyl, terephthaloyl, adipoyl and sebacoyl dichlorides have been produced The yield and the values of reduced viscosity of the polyesters were found to be affected by the kind of organic phase, the quantitative ratio of organic to aqeuous phase, concentration of hydrogen chloride acceptor, rate of acid chloride addition, contribution of benzyltriethylammonium chloride as a catalyst and the temperature of the polycondensation reactionIn order to characterize these polymers the necessary model compounds were prepared from I or II and benzoyl chloride The resulting polyesters were characterized by IR, elemental analyses, viscometry, DTA, DSC measurements and thermogravimetric analy sis The crystallinity of all polyesters was examined by X-ray analysis In addition the electrical properties of the polyeste
28 citations
TL;DR: A case of coma due to the drinking of a liquid cement for polyvinyl chloride resin, containing acetone, methyl ethyl ketone, cyclohexanone and polyvinYL chloride is described, and possible interactions between sake ingestion and cyclo hexanone metabolism is proposed.
Abstract: A case of coma due to the drinking of a liquid cement for polyvinyl chloride resin, containing acetone, methyl ethyl ketone, cyclohexanone and polyvinyl chloride is described. The patient also simultaneously ingested the alcoholic beverage, sake. After gastric lavage, plasma exchanges and direct hemoperfusions, the patient recovered. The concentrations of these chemicals in plasma and urine were analyzed at various time intervals to estimate the clearance. The elimination half lives for acetone and methyl ethyl ketone were 18 hours and 10 hours, respectively. Although cyclohexanone made up the largest component in the solvents, the blood level was extremely low and a large amount of cyclohexanol, a metabolite of cyclohexanone was detected in the blood and urine. The glucuronide metabolite of cyclohexanol was also estimated after the hydrolysis with β-glucuronidase. Since the conversion of cyclohexanone to cyclohexanol is known to be catalyzed by alcohol dehydrogenase, possible interactions between...
24 citations
TL;DR: Kinetic investigations under steady-state conditions demonstrate that the flavoprotein prosthetic group, FMN, is involved in the monooxygenase catalytic mechanism.
Abstract: A soluble cyclohexanone monooxygenase was purified 16.1-fold to homogeneity from a Xanthobacter sp. grown upon cyclohexane as sole source of carbon and energy. The native enzyme is a 50-kDa single polypeptide chain associated with FMN rather than FAD as flavin prosthetic group in a 1:1 stoichiometric relationship. The monooxygenase catalyses the transformation of cyclohexanone to the lactone 1-oxa-2-oxocycloheptane in an oxygen ring insertion reaction. Only related cycloalkanone substrates are accepted for oxygenation, no activity is shown towards straight-chain alkanones. Enzyme activity is strongly inhibited by sulphydryl-reactive agents, but is relatively insensitive to metal chelators, electron transport inhibitors and the metal ions Fe3+ and Cu2+. Cyclohexanone monooxygenase has Km values for cyclohexanone and NADPH of <0.5 μM and 12.5 μM respectively. Kinetic investigations under steady-state conditions demonstrate that the flavoprotein prosthetic group, FMN, is involved in the monooxygenase catalytic mechanism. The systematic name for the enzyme is cyclohexanone, NADPH:oxygen oxidoreductase (6-hydroxylating, 1,2-lactonizing) (EC 1.14.13.22).
TL;DR: In this article, an ELM process for selective removal of acrylic acid from acrylic acid-propionic acid mixtures was developed through incorporation of a co-solvent (cyclohexanone) in the membrane phase of the emulsion.
Abstract: Emulsion liquid membrane (ELM) extraction of low molecular weight organic acids resulting from whey fermentations was investigated. Rates of removal of lactic, acetic, propionic, and acrylic acids decreased as pH and concentration were increased. An ELM process for selective removal of acrylic acid from acrylic acid-propionic acid mixtures was developed through incorporation of a co-solvent (cyclohexanone) in the membrane phase of the emulsion. Degree of removal for each acid and, hence, selectivity among the acids appears to be determined by the water-membrane phase partition coefficient.
TL;DR: The reaction of fluorinated phenylthioureas, with some new fluorine-containing 3-(2-oxocycloalkylidene) indol-2-ones (2) in ethanolic KOH medium, yielded a series of new fluorines containing 5′, 6′-cyclopenta-2′-thioxo-3′-phenyl spiro [3H-indole-3,4′(3′H)-quinazolin] -2(1H)-ones in 55-68% yields RE
TL;DR: The regeneration of nicotinamide-adenine dinucleotide by the reaction of NAD with hydrogen gas was carried out in the presence of the hydrogenase from Alcaligenes eutrophus and the formations of alcohol, CO2, and 6-phospho-gluconate were observed by a combination of the above system and corresponding dehydrogenases.
TL;DR: In this paper, a typical odorant molecule, cyclohexanone, which is semipolar in the sense that the dipolar functional group (a carbonyl) is part of a small, non-polar hydrocarbon ring, is presented.
TL;DR: In this paper, substituted cyclohexanones are effectively reduced to the corresponding alcohols using propan-2-ol as hydrogen source and Rh(I) complexes with 1,10-phenanthroline (phen) and substituted derivatives as catalyst precursors.
TL;DR: Deconjugaison photochimique de l'isophorone (trimethyl-3,5,5 cyclohexene-2 one) en dimethyl 3,3 methylene-5 cycloehexanone.
Abstract: Deconjugaison photochimique de l'isophorone (trimethyl-3,5,5 cyclohexene-2 one) en dimethyl-3,3 methylene-5 cyclohexanone
TL;DR: In this article, the excess enthalpies of five alkanols + cyclohexanone were measured at atmospheric pressure and 298.15 K. The experimental values HmE of each of (one of the five alkansols + tetrahydrofuran) are larger than those of the corresponding (alkanol + tetrahedro-furan).
TL;DR: Poly(styrene-co-divinylbenzene) bound sulphonyl hydrazine was prepared and its reactions with cyclohexanone, 1,3- and 1,4-cyclohexandione were investigated as mentioned in this paper.
TL;DR: The first-order rate dependence on concentrations of the Q band-excited catalyst species suggests that the same bimolecular mechanism between the excited and ground-state species previously proposed for 2-propanol dehydrogenation is applicable to cyclohexanol as well.
Patent•
06 Mar 1989
TL;DR: In this article, a phenol and/or a cyclohexenone is prepared by dehydrogenation of cycloenone and cycloenenone in liquid phase under the presence of a solid catalyst comprising a platinum-group metal loaded on a carrier.
Abstract: A phenol and/or a cyclohexanone is prepared by dehydrogenation of cyclohexenone and/or a cyclohexenol in liquid phase under the presence of a solid catalyst comprising a platinum-group metal loaded on a carrier. The solid catalyst comprises a carrier selected from activated carbon and hydrotalcites.
TL;DR: Nickel supported on activated carbon was highly active as a catalyst for the dehydrogenation of cyclohexanol to cycloehexanone as mentioned in this paper, and the activity of nickel catalysts strongly depended on the support.
Abstract: Nickel supported on activated carbon was highly active as a catalyst for the dehydrogenation of cyclohexanol to cyclohexanone. The activity of nickel catalysts strongly depended on the support; activated carbon was most efficient, while silica, alumina and magnesia were much less effective.
TL;DR: In this paper, the reaction of cyclohexane oxidation with hydrogen peroxide and chloro-tetratolylporphyrinatochromium(III) as a catalyst has been investigated.
TL;DR: The presence of bound co-enzyme significantly inhibits the process(es) leading to inactivation of the enzyme in the microemulsions, which corresponds to progressive loss of functional sites, while the properties of the remaining functional sites are unchanged.
Abstract: Changes in the enzymatic properties of horse liver alcohol dehydrogenase (HLADH; EC 1.1.1.1) were studied as a function of incubation time in Aerosol-OT/isooctane microemulsions. The enzyme was characterized by fluorimetric binding studies of the inhibitor isobutyramide to the binary complex, HLADH-NADH and by determination of Km,app and Vmax,app values for cyclohexanone.
The Km,app values for cyclohexanone and the Kd,app for isobutyramide stay constant throughout a 48-h incubation, whereas the Vmax,app and the total number of inhibitor binding sites decrease. Thus the inactivation process previously described corresponds to progressive loss of functional sites, while the properties of the remaining functional sites are unchanged.
If no co-enzyme is added to the system, the enzyme loses catalytic activity within less than an hour, but if co-enzyme is added, a fraction of the HLADH enzyme population retains enzyme activity over a long period of time. Hence the presence of bound co-enzyme significantly inhibits the process(es) leading to inactivation of the enzyme in the microemulsions.
TL;DR: Cr, Co and Rh were introduced into P-1, P-2 and P2W nickel boride catalysts as promoters in this paper, but Cr and Co were only effective for P- 2W and P- 1 nickel borsides respectively.
Abstract: Cr, Co and Rh were introduced into P-1, P-2 and P-2W nickel boride catalysts as promoters. The substrates of cyclohexanone and cyclohexene were used to examine the effects of those promoters on nickel borides for hydrogenation reactions. On cyclohexanone with strongly-polared carbonyl group, Cr, Co and Rh are effective for all nickel borides. On cyclohexene with slightly-polared olefinic group, Rh is also good for all nickel borides. But Cr and Co are only effective for P-2W and P-1 nickel borides respectively.
TL;DR: In this paper, the first step in the Kindler process is the formation of enamines by reaction of the carbonyl function with secondary aliphatic amines, and then reaction of enamine with certain sulfur-amine catalysts to form reactive heterocyclic sulfur intermediates that facilitate the elimination-readdition of the amines reversibly along the chain.
TL;DR: In this paper, a trisubstituted cyclohexanone derivative was introduced via an epoxy ketone which after reduction was reacted with the diethylaluminium derivative of ethoxyacetylene.