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Phenol
Kinds of Phenol Terms modified by Phenol Selected AbstractsTHE CGP7930 ANALOGUE 2,6-DI- TERT -BUTYL-4-(3-HYDROXY-2-SPIROPENTYLPROPYL)-PHENOL (BSPP) POTENTIATES BACLOFEN ACTION AT GABAB AUTORECEPTORSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2008David AS Parker SUMMARY 1The pharmacological actions of 2,6-di- tert -butyl-4-(3-hydroxy-2-spiropentylpropyl)-phenol (BSPP), a putative presynaptic GABAB receptor modulator, were examined in electrically stimulated rat neocortical brain slices preloaded with [3H]-GABA or [3H]-glutamic acid. 2At 10 mmol/L, BSPP inhibited the release of [3H]-GABA in the presence of baclofen, but not that of [3H]-glutamic acid. This effect was sensitive to the GABAB receptor antagonist (+)-(S)-5,5-dimethylmorpholinyl-2-acetic acid (Sch 50911). 3Alone, BSPP had no effect on the release of [3H]-GABA or [3H]-glutamic acid. 4It is concluded that BSPP selectively potentiates the action of baclofen at GABAB autoreceptors, but not heteroreceptors and may be a useful ligand to discriminate between presynaptic GABAB receptor subtypes. [source] STABILITY OF ANTHOCYANINS, PHENOLS AND FREE RADICAL SCAVENGING ACTIVITY THROUGH SUGAR ADDITION DURING FROZEN STORAGE OF BLACKBERRIESJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009MIRELA KOPJAR ABSTRACT Influence of sugar and mixtures of sugar on color retention of two varieties of blackberries, Thornfree and Cacanska bestrna, were investigated during storage at ,18C for 12 months. After harvest, blackberries were coated with sugars (sucrose, fructose and glucose) and different sugar (sucrose + fructose + glucose, fructose + glucose, fructose + sucrose) mixtures. Anthocynin content, total phenol content and free radical scavenging activity of prepared samples were evaluated. Ratio of fruit : sugar was 1:1. The highest anthocyanin retention was in blackberry samples with glucose addition and the lowest in samples with sucrose addition, in both cultivars. Blackberry samples with sucrose addition had even lower retention than samples without sugar addition. Samples with an addition of other sugars had higher retention of anthocyanin than samples stored without sugars. PRACTICAL APPLICATION Possibility of phenols retention of blackberries due to sugar addition, during cold storage was investigated. Results showed that glucose had the most positive effect on anthocyanins retention as well as total phenolic compounds content. For that reason, certain amount of sucrose in fruit preserves can be replaced by addition of glucose, and for that reason retention of phenolic compounds can be higher and, as could be expected, more effective against oxidative stress in human body due to intake of product formulation with glucose. [source] Digital Block With and Without Epinephrine During Chemical Matricectomy with PhenolDERMATOLOGIC SURGERY, Issue 10 2010H. CEVDET ALTINYAZAR MD BACKGROUND Digital block with epinephrine is safe in selected patients. Chemical matricectomy with phenol is a successful, cheap, and easy method for the treatment of ingrown nails. OBJECTIVE To determine the effect of digital block with epinephrine in chemical matricectomy with phenol. MATERIAL AND METHODS Forty-four patients with ingrown toenail were randomly divided into two groups. The plain lidocaine group (n=22) underwent digital anesthesia using 2% plain lidocaine, and the lidocaine with epinephrine group (n=22) underwent digital anesthesia with 2% lidocaine with 1:100,000 epinephrine. In the postoperative period, the patients were evaluated for pain, drainage, and peripheral tissue destruction and were followed for up to 18 months for recurrence. RESULTS The mean anesthetic volume used in the epinephrine group (2.2±0.4 mL) was significantly lower than the plain lidocaine group (3.1±0.6 mL). There was no statistically significant difference in postoperative pain and recurrence rates, but duration of drainage was significantly shorter in the epinephrine group (11.1±2.5 days) than in the plain lidocaine group (19.0±3.8 days). CONCLUSION Digital block with epinephrine is safe in selected patients, and epinephrine helps to shorten the postoperative drainage period. The authors have indicated no significant interest with commercial supporters. [source] Minimizing Postoperative Drainage with 20% Ferric Chloride After Chemical Matricectomy with PhenolDERMATOLOGIC SURGERY, Issue 2 2001A. Burhan Aksakal MD Background. Phenol used in partial matricectomy shows its effects by denaturing matrix proteins. This highly successful method has the major problem of oozing which can continue for 5,6 weeks. Objective. The goal of this study was to determine the effect of 20% ferric chloride (FC) (FeCl3) on minimizing the oozing after chemical matricectomy with phenol. Methods. Sixty-seven patients with stage III onychocryptosis were treated by chemical matricectomy with 90% aqueous phenol. In 32 of these patients FC was applied to the nail bed after the phenolization procedure. Results. We found a statistically significant (P < .001) reduction of oozing in the FC-applied group of patients. Conclusion. We think that using FC after phenol chemical matricectomy results in a significant reduction in oozing from the operation site. [source] Comparing the solid phase and saline extract Microtox® assays for two polycyclic aromatic hydrocarbon-contaminated soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2004Carolyn M. Acheson Abstract The performance of remedial teatments is typically evaluated by measuring the concentration of specific chemicals. By adding toxicity bioassays to treatment evaluations, a fuller understanding of treatment performance is obtained. The solid phase Microtox® assay is a useful tool in characterizing the toxicity of contaminated soils and sediments. This study compares the performance of the solid phase and saline extract Microtox assays in two experiments using two soils contaminated with polycyclic aromatic hydrocarbons (PAHs). The first experiment, conducted to refine the solid phase assay procedures, evaluated sample holding times, sample replication, and reference toxicant controls. The effective concentration reducing light emission by 50% (EC50) of four samples was measured with eight replicates of each sample. Samples were stored for as long as two weeks without showing substantial changes in toxicity. For future studies, three replicates of each sample are recommended because that degree of replication yielded a statistical power of more than 95% in most samples. Phenol was a reliable reference toxicant with a mean EC50 of 21.76 and a 95% confidence interval of 15.6 to 27.9 mg/L. In a second experiment, the solid phase Microtox assay was compared to saline extract Microtox assays with mixing times ranging from 5 min to 16 h. The solid phase assay was more sensitive yielding EC50s 7 to 50 times lower than the extract EC50s. In addition, the saline extract assays displayed results that varied for mixing times of less than 2 h. Based on these two experiments, the solid phase Microtox test has proved to be a useful assay for measuring the toxicity of PAH-contaminated soils. [source] Stereochemistry of the Conversion of 2-Phenoxyethanol into Phenol and Acetaldehyde by Acetobacterium sp.HELVETICA CHIMICA ACTA, Issue 7 2003Giovanna Speranza The conversion of 2-phenoxyethanol to phenol and acetate by the anaerobic bacterium Acetobacterium sp. strain LuPhet1 proceeds through acetaldehyde with concomitant migration of a H-atom from C(1) to C(2) of the glycolic moiety. Separate feeding experiments with (R)- and (S)-2-phenoxy(1- 2H)ethanol, prepared via chemoenzymatic syntheses, indicate that the H-atom involved in the 1,2-shift is the pro-S one of the enantiotopic couple of the alcohol function. [source] Hydrogenation of Phenol in Supercritical Carbon Dioxide Catalyzed by Palladium Supported on Al-MCM-41: A Facile Route for One-Pot Cyclohexanone FormationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009M. Chatterjee Abstract The hydrogenation of phenol has been carried out in supercritical carbon dioxide (scCO2) under very mild reaction conditions at the temperature of 50,°C over palladium supported Al-MCM-41 (metal loading ,1%). This palladium catalyst is shown to be highly active and promotes the selective formation of cyclohexanone (,98%), an industrially important compound, in a "one-pot" way. The effects of different variables like carbon dioxide and hydrogen pressure, reaction time and also silica/alumina ratio of the MCM-41 support along with palladium dispersion are presented and discussed. The pressure effect of carbon dioxide is significantly prominent in terms of conversion and cyclohexanone selectivity. Moreover, the silica/alumina ratio was also found to be an important parameter to enhance the effectiveness of the catalyst as it exhibits a remarkable increase in phenol conversion from 20.6% to 98.4% as the support changes from only silica MCM-41 to Al-MCM-41. A plausible mechanism for the hydrogenation of phenol to cyclohexanone over the palladium catalyst has been proposed. The proposition is validated by transition state calculations using density functional theory (DFT), which reveal that cyclohexanone is a favorable product and stabilized by <19,kcal,mol,1 over cyclohexanol in scCO2 medium. Under similar reaction conditions, phenol hydrogenation was also carried out with rhodium, supported on Al-MCM-41. In contrast to the palladium catalyst, a mixture of cyclohexanone (57.8%) and cyclohexanol (42.2%) was formed. Detailed characterization by X-ray diffraction and transmission electron microscopy confirmed the presence of metal nanoparticles (palladium and rhodium) between 10,20,nm. Both the catalysts exhibit strikingly different product distributions in solventless conditions compared to scCO2. This method can also be successfully applied to the other hydroxylated aromatic compounds. [source] EFFECT OF STORAGE PERIOD AND EXPOSURE CONDITIONS ON THE QUALITY OF BOSANA EXTRA-VIRGIN OLIVE OILJOURNAL OF FOOD QUALITY, Issue 2 2006VINCENZO VACCA ABSTRACT Changes in quality parameters, antioxidant compounds, oxidative stability and antioxidant activity during 18 months of storage of a monovarietal extra-virgin olive oil from Bosana cultivar, and exposed to light and dark, were studied. Analysis of data showed that all the parameters underwent significant changes during storage: free acidity, peroxide and ultraviolet (UV) spectrophotometric indexes remained below the limits reported in the EEC Regulations 2568/91 and 1989/03, and these are: ,0.8% for acidity, ,20 meq O2/kg for peroxide and ,2.50 and ,0.22 for K232 and K270, respectively. Phenol and, -tocopherol content decreased during storage (42.0 and 29.6%, respectively) while chlorophylls and carotenoids underwent a decrease until 8 months of storage (49% and 30%, respectively); after that, the values remained constant. Oxidative stability and antioxidant activity had not changed dramatically during 18 months. Phenols were significantly correlated to the antioxidant activity of the oil, while oxidative stability measured by Rancimat did not show any correlation with carotenoids, chlorophylls, phenols and, -tocopherol. Regarding exposure conditions, storage in the dark was better in retaining the quality of the oil, as expected. [source] Synthesis of 13C- and 14C-labelled catecholJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2002Rong Ji Abstract 13C- and 14C-uniformly labelled catechol was synthesized from phenol in three steps. Phenol was derivatized with 2-chloro-5-nitrobenzophenone in THF containing NaH, followed by ortho -hydroxylation with 35% aqueous H2O2 in sulphuric acid/glacial acetic acid solution, and by cleavage with piperidine, giving an overall 80% yield with respect to phenol. Copyright © 2002 John Wiley & Sons, Ltd. [source] Phenol, chlorobenzene and chlorophenol isomers: resonant states and dissociative electron attachment,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2003Roustem V. Khatymov This paper reports a study of resonant dissociative electron attachment (DEA) to the phenol, chlorobenzene, p- , m- , and o- chlorophenol molecules. On the basis of spectroscopic and thermochemical approaches the resonant states of the molecular negative ions (NIs) and the structures of some dissociative decay products are assigned. In the electron energy range up to 3,eV, DEA processes are determined by the two 2[,*]-shape resonances resulting mainly in formation of [MH], and/or Cl, ions. At higher electron energies the energy correlation between peaks in the negative ion effective yield curves and bands of UV spectra allowed identification of the core-excited resonances. The peculiarities of Cl, ion formation and the vibrational fine structure on the effective yield curves of the [MH], ions are discussed. The mass spectrometric procedures for measurement of relative cross sections for NI formation are described. Copyright © 2003 John Wiley & Sons, Ltd. [source] The Novel Antioxidant, AC3056 (2,6-di-t-butyl-4-((Dimethyl-4-Methoxyphenylsilyl)Methyloxy)Phenol), Reverses Erectile Dysfunction in Diabetic Rats and Improves NO-mediated Responses in Penile Tissue from Diabetic MenTHE JOURNAL OF SEXUAL MEDICINE, Issue 2 2009Javier Angulo PhD ABSTRACT Introduction., Diabetes is associated with a high incidence of erectile dysfunction (ED) and poor response to standard treatments. Oxidative stress could be relevant in the pathophysiology of diabetic ED. Aim., To evaluate the effects of the antioxidant, AC3056 (2,6-di- t -butyl-4-((dimethyl-4-methoxyphenylsilyl)methyloxy)phenol), on diabetic ED. Methods., Erectile responses to cavernosal nerve electrical stimulation were determined in streptozotocin-induced diabetic rats. Relaxation of human corpus cavernosal (HCC) tissue and penile resistance arteries (HPRA) from human cavernosal specimens was evaluated in organ chambers and myographs, respectively. Main Outcome Measures., The influence of AC3056 on erectile responses, lipid peroxidation, and nitrite plus nitrate serum content, and nuclear factor-,B (NF-,B) expression in penile tissue, in diabetic rats, and on endothelium-dependent and neurogenic relaxation of HCC and HPRA from diabetic patients was determined. Results., Eight weeks of diabetes caused ED in rats that was prevented by oral AC3056 (0.3% w/w in rat chow) when given from the induction of diabetes. AC3056 also prevented the diabetes-induced elevation of serum thiobarbituric acid-reactive substances (TBARS), the reduction of serum nitric oxide (NO) derivatives, and the increase of NF-,B expression. Acute oral administration of AC3056 (450 mg/kg) partially reversed ED in 8-week diabetic rats. Complete reversion of ED was achieved after 3 days of treatment with 0.3% AC3056. This effect remained after 5 weeks of treatment, but it disappeared after withdrawing for 1 week. Erectile function in diabetic rats was inversely related to serum TBARS. AC3056- (30 µM) reversed endothelial dysfunction in diabetic HCC and enhanced endothelium-dependent relaxation in diabetic HPRA and significantly potentiated neurogenic relaxation of both tissues. The reduced cGMP content in HCC from diabetic patients after exposure to acetylcholine (10 µM) was corrected by AC3056 (30 µM). Conclusions., These results suggest that oxidative stress has a relevant role in pathophysiology of diabetic ED and provide a rationale for the use of antioxidant therapy in the treatment of ED in diabetes. Angulo J, Peiró C, Cuevas P, Gabancho S, Fernández A, González-Corrochano R, La Fuente JM, Baron AD, Chen KS, and Sáenz de Tejada I. The novel antioxidant, AC3056 (2,6-di-t-butyl-4-([dimethyl-4-methoxyphenylsilyl] methyloxy) phenol), reverses erectile dysfunction in diabetic rats and improves NO-mediated responses in penile tissue from diabetic men. J Sex Med 2009;6:373,387. [source] Aryl Trifluoroborates in Suzuki,Miyaura Coupling: The Roles of Endogenous Aryl Boronic Acid and Fluoride,ANGEWANDTE CHEMIE, Issue 30 2010Mike Butters Dr. Entscheidender Schritt: Die Biarylkupplung zwischen Aryltrifluorborat und Arylbromid erfordert die In-situ-Hydrolyse des Borreagens. Die Hydrolyseprodukte sind entscheidend dafür, dass die Reaktion mit hoher Effizienz abläuft und möglichst wenig unerwünschte Phenol- und Homokupplungs-Nebenprodukte entstehen. [source] Synthesis of Phenol, Aromatic Ether, and Benzofuran Derivatives by Copper-Catalyzed Hydroxylation of Aryl Halides,ANGEWANDTE CHEMIE, Issue 46 2009Dongbing Zhao Gruppentausch: Die kupferkatalysierte Synthese von Phenolen aus Arylhalogeniden gelang unter relativ milden Reaktionsbedingungen. Alkylarylether und Benzofurane ließen sich glatt durch Eintopf-Dominoreaktionen herstellen, die auf einer Hydroxylierung von Aryliodiden beruhten (siehe Schema). [source] Hydrogen-Bond Control in Axially Chiral Styrenes: Selective Synthesis of Enantiomerically Pure C2 -Symmetric Paracyclophanes,ANGEWANDTE CHEMIE, Issue 31 2009Keiji Mori Dr. Problem gelöst: Eine H-Brücke zwischen einem Phenol- und einem Sulfinyl-O-Atom kann zu axialer Chiralität eines Styrolderivats führen. In einer C2 -symmetrischen Vorstufe mit zwei solchen Sulfinylstyrolmotiven und einem gemeinsamen Diphenolring lässt sich stereoselektiv eine überbrückende Kette synthetisieren (siehe Schema). Auf diesem Weg ist eine Vielzahl an enantiomerenreinen [10]- und [12]Paracyclophanen mit Benzol- oder Naphthalingerüst zugänglich. [source] 5,5,-Di- tert -butyl-2,2,-dihydroxy-3,3,-methylenedibenzaldehyde and 6,6,-di- tert -butyl-8,8,-methylenebis(spiro[4H -1,3-benzodioxin-2,1,-cyclohexane])ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2004Bernardo Masci Two related compounds containing p - tert -butyl- o -methylene-linked phenol or phenol-derived subunits are described, namely 5,5,-di- tert -butyl-2,2,-dihydroxy-3,3,-methylenedibenzaldehyde, C23H28O4, (I), and 6,6,-di- tert -butyl-8,8,-methylenebis(spiro[4H -1,3-benzodioxin-2,1,-cyclohexane]), C35H48O4, (II). Both compounds adopt a `butterfly' shape, with the two phenol or phenol-derived O atoms in distal positions. Phenol and aldehyde groups in (I) are involved in intramolecular hydrogen bonds and the two dioxin rings in (II) are in distorted half-chair conformations. [source] Phenol recovery from simulated wastewater using a vertical membrane reactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010Manoj Jhanwar Abstract Phenol was recovered from the simulated wastewater in the form of a useful product, allyl phenyl ether, using A-172 membrane as phase-transfer catalyst in a batch and a continuous membrane reactor. The effects of temperature, agitation rates and flow rates of aqueous and organic phases, and concentrations of phenol and allyl bromide on the yield of allyl phenyl ether in the organic phase and phenol removal in the aqueous phase after the reaction were studied. Activation energy and turnover number of the reaction were calculated as well. In the batch mode, the phenol concentration in the treated aqueous phase was found to be < 2 ppm, reduced from 5000 ppm, and more than 99% of the phenol was recovered in the form of allyl phenyl ether after reacting for 180 min. In a continuous mode, the phenol concentration can be reduced from 5000 to 100 ppm in the steady state operation of the reactor. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Variable Stoichiometry during the Laccase-Catalyzed Oxidation of Aqueous PhenolBIOTECHNOLOGY PROGRESS, Issue 2 2007Selvia Kurniawati The oxidation of aqueous phenol through the catalytic action of laccase from Trametes versicolor was studied over a wide range of phenol concentrations and enzyme activities. The stoichiometric ratio, which is defined as the molar ratio of phenol transformed to oxygen consumed in the catalytic reaction, was found to increase with phenol concentration in the reaction mixture from a theoretical lower limit of 1 and to approach a theoretical upper limit of 4. A logistic equation was proposed to relate reaction stoichiometry to substrate concentration and was successfully used to relate these parameters over a range of phenol concentrations extending from approximately 0.15 to 8 mM. This expression was incorporated into two kinetic models in order to account for variations in reaction stoichiometry during the reaction and to extend the range over which the models may be accurately applied. The new models demonstrated an improved ability to predict concentrations of phenol and oxygen over time in a closed batch reaction system. [source] Indirect Electrochemical Oxidation of Phenol in the Presence of Chloride for Wastewater TreatmentCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2005D. Rajkumar Abstract Electrochemical oxidation of phenol using a Ti/TiO2 -RuO2 -IrO2 anode in the presence of chloride as the supporting electrolyte was investigated. The experiments were performed in an undivided batch reactor. Preliminary investigations showed that only a small fraction of phenol was oxidized by direct electrolysis, while complete degradation of phenol was achieved by indirect electrochemical oxidation using chloride as a supporting electrolyte. The effect of operating parameters such as initial pH, supporting electrolyte concentration, phenol concentration, and charge input was studied using Box-Behnken second order composite experimental design. The effect of current density on COD removal was studied separately. TOC removal and AOX formation were studied for selected conditions. It was found that the formation of chlorinated organic compounds was pronounced at the beginning of electrolysis, but it was reduced to lower levels by extended electrolysis. [source] Palladium(II)-Catalyzed Aerobic Hydroalkoxylation of Styrenes Containing a Phenol.CHEMINFORM, Issue 28 2006Keith M. Gligorich Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Photooxygenation of Olefins, Phenol, and Sulfide Using Fullerodendrimer as Catalyst.CHEMINFORM, Issue 5 2005Yutaka Takaguchi Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Novel and Convenient Chemoselective Deprotection Method for Both Silyl and Acetyl Groups on Acidic Hydroxyl Groups such as Phenol and Carboxylic Acid by Using a Nitrogen Organic Base, 1,1,3,3-Tetramethylguanidine.CHEMINFORM, Issue 21 2003Kin-ichi Oyama No abstract is available for this article. [source] Aromatic,Carbohydrate Interactions: An NMR and Computational Study of Model SystemsCHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2008Sophie Vandenbussche Ir. Abstract The interactions of simple carbohydrates with aromatic moieties have been investigated experimentally by NMR spectroscopy. The analysis of the changes in the chemical shifts of the sugar proton signals induced upon addition of aromatic entities has been interpreted in terms of interaction geometries. Phenol and aromatic amino acids (phenylalanine, tyrosine, tryptophan) have been used. The observed sugar,aromatic interactions depend on the chemical nature of the sugar, and thus on the stereochemistries of the different carbon atoms, and also on the solvent. A preliminary study of the solvation state of a model monosaccharide (methyl ,-galactopyranoside) in aqueous solution, both alone and in the presence of benzene and phenol, has also been carried out by monitoring of intermolecular homonuclear solvent,sugar and aromatic,sugar NOEs. These experimental results have been compared with those obtained by density functional theory methods and molecular mechanics calculations. [source] Direct Oxidation of Benzene to Phenol by Dioxygen over Nano-vanadium OxideCHINESE JOURNAL OF CHEMISTRY, Issue 11 2009Xiaohan Gao Abstract Reducing regents, such as ascorbic acid, are needed for vanadium-containing catalysts to catalyze the direct oxidation of benzene to phenol by dioxygen. Quadrivalent vanadium species, reduced from quinquevalent vanadium species, can activate dioxygen to produce active oxygen species, which is important for the reaction. The key step is to prepare more V4+ -containing catalysts. Here, VOX -C16 -A was prepared in an acidic medium to produce more V4+ species. The results of XPS and XRD studies confirmed that the vanadium species in VOX -C16 -A was mainly V4+ ions. The results of XRD and electron diffraction patterns revealed that VOX -C16 -A consisted of tetragonal VO2 and monoclinic VO2. Morphology observations display that the VOX -C16 -A is made of nanorod. Investigations into the performances of the catalysts showed that VOX -C16 -A was reusable, producing a 1.9% conversion of benzene without reducing agent. [source] Energy production from the pyrolysis of waste biomassesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2009Selhan Karagöz Abstract Pyrolysis of waste biomasses was carried out at the temperatures of 450 and 500°C by heating at 5°C,min,1. Products were collected from emitted gases in a nitrogen purge stream; condensable liquids in the gases were collected by condensation. Gaseous, condensed liquid products and residual solids were collected and analyzed. Condensates were extracted with ether to recover the bio oils (BOs). The maximum liquid yield was obtained from the pyrolysis of soybean oil cake (SBOC) at 500°C with a yield of 60% ca. The BO was higher in the case of SBOC than that of sunflower oil cake (SFOC) at the temperatures of 450 and 500°C. With increasing temperature, bio char yield from the pyrolysis of SFOC decreased, while the liquid yield increased. The increase in temperature did not significantly affect the product distribution for the pyrolysis of SBOC. The compositions of BOs were similar for both SBOC and SFOC. Phenols, phenol derivatives including guaiacols and alkyl-benzenes were the most common and predominant in BOs from both the pyrolysis of SBOC and SFOC. Carbon dioxide was the major gas product for both SBOC and SFOC. Copyright © 2008 John Wiley & Sons, Ltd. [source] A Novel Process for Selective Ruthenium-Catalyzed Oxidation of Naphthalenes and PhenolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Gerrit Wienhöfer Abstract Arenes are selectively oxidized to the corresponding quinones employing ruthenium(2,2,,6,:2,,-terpyridine)(2,6-pyridinedicarboxylate) [Ru(tpy)(pydic] as catalyst and hydrogen peroxide as the terminal oxidant. Applying alkylated naphthalenes and phenols, benzo- and naphthoquinones are obtained in up to 93% yield. The industrially interesting oxidation of 2-methylnaphthalene gave 74% of the corresponding quinones and 60% of menadione (vitamin K3). 2,3,5-Trimethylbenzoquinone which constitutes the key intermediate for vitamin E is obtained in 83% yield. [source] N-Heterocyclic Carbene-Mediated Enantioselective Addition of Phenols to Unsymmetrical AlkylarylketenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Carmen Concellón Abstract Chiral N-heterocyclic carbenes (NHCs) mediate the enantioselective addition of 2-phenylphenol to unsymmetrical alkylarylketenes, delivering ,-alkyl-,-arylacetic acid derivatives with good levels of enantiocontrol (up to 84% ee). Enantiodivergent stereochemical outcomes are observed using 2-phenylphenol and benzhydrol in the NHC-promoted esterification reaction using a triazolium precatalyst derived from pyroglutamic acid, consistent with distinct mechanistic pathways operating within these processes. [source] Regioselective Synthesis of Phenols and Halophenols from Arylboronic Acids Using Solid Poly(N -vinylpyrrolidone)/ Hydrogen Peroxide and Poly(4-vinylpyridine)/Hydrogen Peroxide ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009K. Surya Prakash Abstract Solid hydrogen peroxide complexes based on poly(N -vinylpyrrolidone) and poly(4-vinylpyridine) were prepared and used as solid hydroxylating reagents. These solid hydrogen peroxide equivalents are found to be much safer, convenient and efficient reagent systems for the ipso -hydroxylation of arylboronic acids to the corresponding phenols in high yields at a faster rate. The versatility of the reagents has been further expanded for the one-pot synthesis of halophenols. Density functional theory calculations were carried out on hydrogen peroxide complexes of N -ethylpyrrolidone and 4-ethylpyridine as models to get a better understanding of structure and behavior of hydrogen peroxide complexes of the polymers poly(N -vinylpyrrolidone) and poly(4-vinylpyridine) compared to aqueous hydrogen peroxide. [source] Cationic Ruthenium-Cyclopentadienyl-Diphosphine Complexes as Catalysts for the Allylation of Phenols with Allyl Alcohol; Relation between Structure and Catalytic Performance in O - vs.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009C -Allylation Abstract A new catalytic method has been investigated to obtain either O - or C -allylated phenolic products using allyl alcohol or diallyl ether as the allyl donor. With the use of new cationic ruthenium(II) complexes as catalyst, both reactions can be performed with good selectivity. Active cationic Ru(II) complexes, having cyclopentadienyl and bidentate phosphine ligands are generated from the corresponding Ru(II) chloride complexes with a silver salt. The structures of three novel (diphosphine)Ru(II)CpCl catalyst precursor complexes are reported. It appears that the structure of the bidentate ligand has a major influence on catalytic activity as well as chemoselectivity. In addition, a strong cocatalytic effect of small amounts of acid is revealed. Model experiments are described that have been used to build a reaction network that explains the origin and evolution in time of both O -allylated and C -allylated phenolic products. Some mechanistic implications of the observed structure vs. performance relation of the [(diphosphine)RuCp]+ complexes and the cocatalytic role of added protons are discussed. [source] Novel [Ruthenium(substituted-tetramethylcyclopentadiene) (2-quinolinecarboxylato)(allyl)] Hexafluorophosphate Complexes as Efficient Catalysts for Highly Regioselective Nucleophilic Substitution of Aliphatic Allylic SubstratesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2008Hui-Jun Zhang Abstract Stable [ruthenium(R-substituted-tetramethylcyclopentadiene)(2-quinolinecarboxylato)(1-R,-substituted-allyl) hexafluorophosphate (R=Me, R,=H, Me, n- Pr, Ph; R=t- Bu, R,=Me) and [ruthenium(pentamethylcyclopentadiene)(2-quinolinecarboxylato)(1- n -propylallyl)] tetrafluoroborate (4,a), as allylruthenium(IV) complexes, have been synthesized in one step, starting from [ruthenium(R-substituted-tetramethylcyclopentadiene)tris(acetonitrile) hexafluorophosphate or tetrafluoroborate complexes, quinaldic acid, and allylic alcohols. Single stereoisomers are obtained and the X-ray single crystal structure determinations of 3b (R=t- Bu, R,=Me) and 4,a allow one to specify the preferred arrangement. Complexes 3a (R=R,=Me) and 3b are involved as precatalysts favoring the formation of branched products in regioselective nucleophilic allylic substitution reactions, starting from ethyl 2- (E) -hexen-1-yl carbonate and chlorohexene as unsymmetrical aliphatic allylic substrates. Phenols, dimethyl malonate, and primary (aniline) and secondary (pyrrolidine, piperidine) amines have been used as nucleophiles under mild basic conditions. For the first time, the regioselectivity in favor of the branched product obtained from purely aliphatic allylic substrates is close to the high regioselectivity previously reached starting from cinnamyl-type substrates in the presence of ruthenium catalysts. [source] Theoretical Studies on ortho -Oxidation of Phenols with Dioxygen Mediated by Dicopper Complex: Hints for a Catalyst with the Phenolase Activity of TyrosinaseADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007Hiroshi Naka Abstract Theoretical studies on the chemo- and regioselective ortho -oxidation reaction of phenols mediated by a biomimetic (,,,2:,2peroxo)dicopper(II) complex were performed using unrestricted hybrid density functional theory (UB3LYP) calculations, with the aim of providing a guide for the development of new bio-inspired catalysts with the phenolase activity of tyrosinase. Energetic, structural, and electronic analyses suggested the involvement of a side-on (,,,2:,2)-Cu2O2 complex as an active intermediate, and a single electron transfer (SET)-induced electrophilic aromatic substitution mechanism is proposed for the rate-determining CO bond forming process; this is consistent with experimental observations. Moreover, the inherent roles of, and requirement for, two copper ions in this reaction have been elucidated. [source] | |||||||||||||||||||||||||||||||||||||||||||