- Preparation of nitrogen doped K2Nb4O11 with high photocatalytic activity for degradation of organic pollutants
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Nitrogen doped K2Nb4O11 (K 2Nb4O11-N) has been prepared by solid state reaction between K2Nb4O11 and urea at 400 °C. K2Nb4O11-N has been characterized by XRD, SEM, XPS and UV/vis diffuse reflectance. The photodegradation of various organic pollutants in water by this material, including Orange G (OG), bisphenol A (BPA) and pentachlorophenol (PCP) have been studied at λ > 330 nm and >399 nm. The results show that the photocatalytic activity of K 2Nb4O11-N at >399 nm is higher than those of K2Nb4O11 and Degussa TiO2 P25, indicating the activating effect of nitrogen doping. A mechanism for the photodegradation of organic substrates by K2Nb4O 11-N is proposed.
- Qiu, Yongfu,Wang, Lei,Leung, Chi-Fai,Liu, Guijian,Yang, Shihe,Lau, Tai-Chu
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Read Online
- Biodegradation of bisphenol A by cultured cells of Caragana chamlagu.
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The biological degradation of 2,2-bis(4-hydroxyphenol)propane (1; bisphenol A, BPA), a representative endocrine disruptor, was studied with plant-cultured cells of Caragana chamlagu. An initial BPA concentration of 425 microM in an aqueous solution was degraded by C. chamlagu at 25 degrees C for 2 days in the dark, and two intermediates were then completely dissipated after 10 days.
- Chai, Wen,Sakamaki, Hiroshi,Kitanaka, Susumu,Saito, Michihiko,Horiuchi, C Akira
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Read Online
- Oxidative degradation of toxic organic pollutants by water soluble nonheme iron(iv)-oxo complexes of polydentate nitrogen donor ligands
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The ability of four mononuclear nonheme iron(iv)-oxo complexes supported by polydentate nitrogen donor ligands to degrade organic pollutants has been investigated. The water soluble iron(ii) complexes upon treatment with ceric ammonium nitrate (CAN) in aqueous solution are converted into the corresponding iron(iv)-oxo complexes. The hydrogen atom transfer (HAT) ability of iron(iv)-oxo species has been exploited for the oxidation of halogenated phenols and other toxic pollutants with weak X-H (X = C, O, S,etc.) bonds. The iron-oxo oxidants can oxidize chloro- and fluorophenols with moderate to high yields under stoichiometric as well as catalytic conditions. Furthermore, these oxidants perform selective oxidative degradation of several persistent organic pollutants (POPs) such as bisphenol A, nonylphenol, 2,4-D (2,4-dichlorophenoxyacetic acid) and gammaxene. This work demonstrates the utility of water soluble iron(iv)-oxo complexes as potential catalysts for the oxidative degradation of a wide range of toxic pollutants, and these oxidants could be considered as an alternative to conventional oxidation methods.
- Jana, Rahul Dev,Munshi, Sandip,Paine, Tapan Kanti
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p. 5590 - 5597
(2021/05/04)
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- Synthesis of Tertiary Benzylic Nitriles via Nickel-Catalyzed Markovnikov Hydrocyanation of α-Substituted Styrenes
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The Markovnikov hydrocyanation of α-substituted styrenes enables the synthesis of tertiary benzylic nitriles under nickel catalysis. The Lewis-acid-free transformation features an unprecedented functional groups tolerance, including the-OH and-NH2 groups. A broad range of tertiary benzylic nitriles were obtained in good to excellent yields. In addition, an asymmetric version of this reaction was preliminarily investigated.
- Xing, Yidan,Yu, Rongrong,Fang, Xianjie
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supporting information
p. 1008 - 1012
(2020/02/04)
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- Degradation of bisphenol A and acute toxicity reduction by different thermo-tolerant ascomycete strains isolated from arid soils
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Four different laccase-producing strains were isolated from arid soils and used for bisphenol A (BPA) degradation. These strains were identified as Chaetomium strumarium G5I, Thielavia arenaria CH9, Thielavia arenaria HJ22 and Thielavia arenaria SM1(III) by internal transcribed spacer 5.8 S rDNA analysis. Residual BPA was evaluated by HPLC analysis during 48 h of incubation. A complete removal of BPA was observed by the whole cell fungal cultures within different times, depending on each strain. C. strumarium G5I was the most efficient degrader, showing 100% of removal within 8 h of incubation. The degradation of BPA was accompanied by the production of laccase and dye decolorizing peroxidase (DyP) under degradation conditions. The presence of aminobenzotriazole (ABT) as an inhibitor of cytochrome P450s monooxygenases (CYP) demonstrated a slight decrease in BPA removal rate, suggesting the effective contribution of CYP in the conversion. The great involvement of laccase in BPA transformation together with cell-associated enzymes, such as CYP, was supported by the identification of hydroxylated metabolites by ultra-high performance liquid chromatography-mass spectroscopy (UHPLC-MS). The metabolic pathway of BPA transformation was proposed based on the detected metabolites. The acute toxicity of BPA and its products was investigated and showed a significant reduction, except for T. arenaria SM1(III) that did not caused reduction of toxicity (IC50 8%), possibly due to the presence of toxic metabolites. The results of the present study point out the potential application of the isolated ascomycetes in pollutant removal processes, especially C. strumarium G5I as an efficient degrader of BPA.
- Mtibaà, Rim,Olicón-Hernández, Dario Rafael,Pozo, Clementina,Nasri, Moncef,Mechichi, Tahar,González, Jesus,Aranda, Elisabet
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- Multienzyme One-Pot Cascade for the Stereoselective Hydroxyethyl Functionalization of Substituted Phenols
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The operability and substrate scope of a redesigned vinylphenol hydratase as a single biocatalyst or as part of multienzyme cascades using either substituted coumaric acids or phenols as stable, cheap, and readily available substrates are reported.
- Payer, Stefan E.,Pollak, Hannah,Schmidbauer, Benjamin,Hamm, Florian,Juri?i?, Filip,Faber, Kurt,Glueck, Silvia M.
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p. 5139 - 5143
(2018/09/13)
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- Novel synthesis of Ag decorated TiO2 anchored on zeolites derived from coal fly ash for the photodegradation of bisphenol-A
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The disposal of millions of tons of coal fly ash (CFA) threatens the environment, hence means to reuse CFA are highly sought after. In this study, CFA was reused to make materials which were tested for water purification. Zeolitic material (CFA-Zeo) was derived from CFA by a 2-step alkali-fusion hydrothermal method and then composited with TiO2 nanoparticles using a novel resin-gel technique. CFA-Zeo loadings were 15 and 30 wt% in the resulting TiO2/CFA-Zeo composites. These composites were then loaded with 1 wt% Ag nanoparticles by a deposition-precipitation technique using NaOH and urea. CFA-Zeo rods (morphology confirmed by TEM) were confirmed by PXRD to be sodium aluminum silicate hydrate. TEM analyses of the CFA-Zeo rods in the composites revealed them to be completely coated with TiO2 nanoparticles that had Ag nanoparticles on their surfaces. The photoluminescence emission peak of TiO2 was found to be significantly higher than that of TiO2/CFA-Zeo composites, with the TiO2/CFA-Zeo composites that were loaded with Ag having even lower emission intensities. UV-vis DRS spectra showed that CFA-Zeo had no effect on the band gap of TiO2, while composites that contained Ag had a wide absorption band in the visible region. The photocatalytic efficiency of these materials was then determined using bisphenol-A (BPA) as a model compound under both UV and visible light. Except for the 30 wt% TiO2/CFA-Zeo composites without Ag, all of the composites had superior photoactivity to uncomposited TiO2 under both UV and visible light. On the other hand, composites with Ag nanoparticles showed the best photoactivities. The superior photoactivities of these composites under UV-light were mainly attributed to the separation of charge carriers, whereas under visible light it was attributed to the ability of silver to harvest visible light through surface plasmon resonance (SPR).
- Hlekelele, Lerato,Franklyn, Paul J.,Dziike, Farai,Durbach, Shane H.
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supporting information
p. 1902 - 1912
(2018/02/09)
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- Regioselective Copper-Catalyzed Oxidative Coupling of α-Alkylated Styrenes with Tertiary Alkyl Radicals
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A radical-mediated oxidative cross-coupling of readily accessible α-alkylated styrenes with 1,3-dicarbonyl compounds utilizing a combination of Cu(OAc)2 and air as a catalytic system is described. Rather than requiring α-halocarbonyl compounds, this efficient approach enables direct installation of tertiary functionalized alkyl motifs to olefins with simple carbonyl derivatives. The novel protocol is characterized with high allylic selectivities via a competing β-H elimination. Both radical-clock and -trapping experiments provided clear-cut evidence for the intermediacy of an α-keto carbon-centered radical.
- Wang, Cong,Liu, Rui-Hua,Tian, Ming-Qing,Hu, Xu-Hong,Loh, Teck-Peng
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supporting information
p. 4032 - 4035
(2018/07/15)
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- Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system
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Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/ anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p-And m-Alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.
- Du, Lei,Dong, Sheng,Zhang, Xingwang,Jiang, Chengying,Chen, Jingfei,Yao, Lishan,Wang, Xiao,Wan, Xiaobo,Liu, Xi,Wangi, Xinquan,Huang, Shaohua,Cui, Qiu,Feng, Yingang,Liu, Shuang-Jiang,Li, Shengying
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p. E5129 - E5137
(2017/07/04)
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- Synthesis of poly(isopropenylphenoxy propylene carbonate) and its facile side-chain functionalization into hydroxy-polyurethanes
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4-Isopropenyl phenol (4-IPP) is a versatile dual functional intermediate that can be prepared readily from bisphenol-A (BPA). Through etherification with epichlorohydrin to the phenolic group of 4-IPP, it can be converted into 4-isopropenyl phenyl glycidyl ether (IPGE). On further reaction with carbon dioxide in the presence of tetra-n-butyl ammonium bromide (TBAB) as the catalyst, IPGE was transformed into 4-isopropenylphenoxy propylene carbonate (IPPC) in 90% yield. Cationic polymerization of IPPC with strong acid such as trifluoromethanesulfonic acid or boron trifluoride diethyl etherate as the catalyst at -40 C gave a linear poly(isopropenylphenoxy propylene carbonate), poly(IPPC), with multicyclic carbonate groups substituted uniformly at the side-chains of the polymer. The cyclic carbonate groups of poly(IPPC) were further reacted with different aliphatic amines and diamines resulting in formation of polymers with hydroxy-polyurethane on side-chains. Syntheses, characterizations of poly(IPPC) and its conversion into hydroxy-polyurethane crosslinked polymers were presented.
- Huang, Chun Chieh,Lin, Ching Hsuan,Dai, Shenghong A.
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p. 802 - 808
(2016/03/12)
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- Regioselective enzymatic β-carboxylation of para-hydroxy-styrene derivatives catalyzed by phenolic acid decarboxylases
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Abstract We report on a 'green' method for the utilization of carbon dioxide as C1 unit for the regioselective synthesis of (E)-cinnamic acids via regioselective enzymatic carboxylation of para-hydroxystyrenes. Phenolic acid decarboxylases from bacterial sources catalyzed the β-carboxylation of para-hydroxystyrene derivatives with excellent regio- and (E/Z)-stereoselectivity by exclusively acting at the β-carbon atom of the C=C side chain to furnish the corresponding (E)-cinnamic acid derivatives in up to 40% conversion at the expense of bicarbonate as carbon dioxide source. Studies on the substrate scope of this strategy are presented and a catalytic mechanism is proposed based on molecular modelling studies supported by mutagenesis of amino acid residues in the active site.
- Wuensch, Christiane,Pavkov-Keller, Tea,Steinkellner, Georg,Gross, Johannes,Fuchs, Michael,Hromic, Altijana,Lyskowski, Andrzej,Fauland, Kerstin,Gruber, Karl,Glueck, Silvia M.,Faber, Kurt
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p. 1909 - 1918
(2015/06/02)
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- Strategy to prepare 4-hydroxylphenyl propargyl ether-based benzoxazine from bisphenol A
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4-Aminophenyl propargyl ether/phenol-based benzoxazine (P-appe) has been reported by many authors. However, to the best of our knowledge, its isomer: 4-hydroxylphenyl propargyl ether/aniline-based benzoxazine (HPPE-a) has never been prepared in the literature. The precursor for HPPE-a, the 4-hydroxylphenyl propargyl ether, is difficult to prepare from hydroquinone without tedious separation because the reactivity of the two hydroxyls in hydroquinone is the same. In this study, we report a straightforward strategy to prepare HPPE-a from bisphenol A by a four-step process including thermolysis, nucleophilic substitution, oxidation, and Mannich-type condensation. The structure was well characterized by NMR, IR, and high resolution mass spectra. Two exothermic peaks at 228 °C and 249°C were observed in the DSC thermogram of HPPE-a. According to IR analysis, the first exotherm is related with the ring opening of the oxazine, and the second exotherm is related with Claisen rearrangement of propargyl ether. Since P-appe and HPPE-a are structural isomers, the structure-property relationship of these two benzoxazines was discussed. We found that the thermal properties of a thermoset of HPPE-a are slightly lower or comparable to those of a thermoset of P-appe, but much higher than that of phenol/aniline-based benzoxazine (P-a).
- Huang, Chun Chieh,Lin, Ching Hsuan,Dai, Shenhong A.
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p. 74874 - 74880
(2015/09/21)
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- Preparation of magnetic composite photocatalyst Bi2WO 6/CoFe2O4by two-step hydrothermal method and itsphotocatalytic degradation of bisphenol A
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Easily separable magnetic photocatalyst Bi2WO 6/CoFe2O4 was synthesized by a two-step hydrothermal method. Pure spinel CoFe2O4 in nano-scale was prepared by a hydrothermal method, which was followed by a second hydrothermal process to coat CoFe2O4 with Bi2WO6. The prepared Bi2WO6/CoFe2O4 kept the magnetic property of CoFe2O4 and high efficient photocatalytic activity of Bi2WO6 as well. The photoactivity of Bi2WO6/CoFe2O4 (mass ratio 10:1) to degrade bisphenol A (BPA) was close to that of pure Bi 2WO6 after 120 min of simulated solar light irradiation. After reaction, the catalyst particles could be easily harvested from the suspension by applying an external magnetic field.
- Wang, Chunying,Zhu, Lingyan,Chang, Chun,Fu, Yu,Chu, Xiaolong
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- Oligomeric hydroxy-aryloxy phosphazene based on cyclic chlorophosphazenes
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Reaction of hexachlorocyclotriphosphazene and a mixture of cyclic chlorophosphazene [NPCl2]n =3-8 with an excess of diphenylolpropane under different conditions affords corresponding oligomeric hydroxy-aryloxy phosphazenes, which were characterized by gas chromatography-mass spectrometry, laser mass spectrometry, 31P and 1H NMR spectroscopy. Side reactions was found with participation of decomposition products of diphenylolpropane. Pleiades Publishing, Ltd., 2013.
- Sirotin,Bilichenko,Brigadnov,Kireev,Suraeva,Borisov
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p. 1903 - 1912
(2014/05/06)
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- PROCESS FOR PRODUCING BISPHENOL A
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The invention relates to producing bisplienol A from phenol and acetone by way of catalytic condensation in the presence of promoted, sulfonated ion- exchange resins, with using fractional crystallization to isolate the p,p'-BPA isomer. The condensation reaction of acetone and phenol is carried out in a multi? stage reaction system with the interstage control of reaction temperature and acetone concentration as well as with the control of water concentration before the last stage of the reaction system. A part of post-crystallization liquors from solvent crystallizations is recycled to the last reactor. Water and acetone are evaporated from the post-reaction mixture which, subsequently, is mixed with the effluent solution from fractional crystallization dissolved in the isomerizate obtained in the process of isomerization of a part of the stream of concentrated liquors after solvent crystallization, the resulting stream is subjected to solvent crystallization, the isolated bisphenol A/phenol adduct is subjected to thermal decomposition, and the resulting raw bisphenol A is subjected to fractional crystallization.
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Page/Page column 12
(2008/12/08)
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- METHOD OF RECOVERING BISPHENOL A FROM WASTE PLASTIC
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PROBLEM TO BE SOLVED: To provide a method of recovering bisphenol A which can recover low purity bisphenol A as high purity bisphenol A. SOLUTION: The method of recovering bisphenol A which comprises a main reaction step 2 of reacting phenol with acetone in the presence of an acidic catalyst to obtain a reaction product containing bisphenol A, a distillation and separation step 4 of distilling the reaction product to separate a vaporized product, a crystallization and recovery step 6 of separating the reaction product separated from the vaporized product into an adduct crystal of bisphenol A and phenol and a mother liquor and recovering the bisphenol A from the adduct crystal, and a circulation step 8 of recirculating the separated liquor to the main reaction step has a mixing step 10 of mixing a crude liquor containing low purity bisphenol A recovered from a decomposition product obtained by the thermal or chemical decomposition of a waste plastic into the mother liquor separated from the adduct crystal or the reaction product separated from the vaporized product.
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Page/Page column 7-8
(2008/06/13)
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- Kinetics and mechanism of p-isopropenylphenol synthesis via hydrothermal cleavage of bisphenol A
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Although bishydroxyarylalkanes are known to be reactive in high-temperature (T > 200 °C) liquid water (HTW), no mechanistic insight has been given to explain the reactivity of methylene bridge-containing diaryls under hydrothermal conditions. We examined the kinetics and mechanism of p-isopropenylphenol (IPP) synthesis via bisphenol A (BPA) cleavage in HTW. The cleavage reaction is first order in BPA. Cleavage of BPA in HTW occurs by specific acid catalysis, by specific base catalysis, and by general water catalysis. Under neutral conditions, the dominant mechanism is general base catalysis with water serving as the proton acceptor. We generated a detailed chemical kinetics model for the decomposition reaction based on a base-catalyzed mechanism in the literature. This three-parameter model fit the experimental data for BPA disappearance and formation of IPP and phenol and accurately predicted the yield of the IPP hydrolysis product acetone. Using acid- and base-catalyzed mechanisms, we explain the reactivity in HTW reported for other diaryl groups linked by methylene bridges and propose criteria for assessing the reactivity of methylene bridges under hydrothermal conditions.
- Hunter, Shawn E.,Savage, Phillip E.
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p. 4724 - 4731
(2007/10/03)
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- Generation and synthetic uses of stable 4-[2-isopropylidene]-phenol carbocation from bisphenol A
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(Equation Presented) Stable 4-[2-isopropylidene]-phenol carbocation, IPP cation 1, was generated readily by addition of bisphenol A in concentrated sulfuric acid at ambient temperature, and the cation could be used for facile syntheses of 4-isopropenyl phenol (IPP), IPP dimers, and spiro-bisphenol derivatives.
- Chen, Wei-Fu,Lin, Hsing-Yo,Dai, Shenghong A.
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p. 2341 - 2343
(2007/10/03)
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- Pinacolboratamethyl-enetriphenylphosphonium iodide, a new methylene transfer reagent
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The title compound is easily prepared and reacts with various aldehydes and ketone. The reagent is compatible with free hydroxy groups. Yields with various aldehydes and ketones are in 50- > 99% range. Both aliphatic, aromatic and unsaturated carbonyls react.
- Al-Aziz Quntar, Abed,Srebnik, Morris
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p. 2575 - 2579
(2007/10/03)
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- Chavicol and Related Compounds as Nematocides
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In a search for nematocidal compounds from wild plant sources, chavicol and demethyleugenol were found from V. furcatum, and 4-vinylphenol was found from three Rosaceae species.These three compounds each contained both p-hydroxyphenyl and exo-methylene moieties, and several related compounds were prepared and tested for nematocidal activity.The results show that the hydroxyphenyl group was essential for the activity, while the aliphatic substituents on the benzene ring enhanced it.The strongest activity was found with 4-propenylphenol.
- Yoshizawa, Yuko,Kawaii, Satoru,Kanauchi, Masatoshi,Chida, Manami,Mizutani, Junya
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p. 1572 - 1574
(2007/10/02)
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- RECTIONS OF HYDROXYL RADICALS WITH POLYMERIZABLE OLEFINS
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The reactions of hydroxyl radicals with methyl acrylate, methyl methacrylate, styrene, and α-methylstyrene have been investigated by a trapping technique which uses 1,1,3,3-tetramethylisoindolin-2-yloxyl (1) as a radical scavenger.The major reaction pathway in each case was addition to the unsubstituted (tail) end of the monomer, although addition to the substituted (head) end and reaction with the double-bond substituents were also observed.Absolute rates of reaction were estimated by means of competition experiments using cyclohexane as reference substrate.The implications of the results for the structure of polymers initiated by hydroxyl radicals are discussed.
- Grant, Richard D.,Rizzardo, Ezio,Solomon, David H.
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p. 379 - 384
(2007/10/02)
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- Selective Indirect Oxidation of Phenol to Hydroquinone and Catechol
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The introduction of a hydroxyl function into phenol to give hydroquinone and catechol can be achieved in high yields by the reaction of hydrogen peroxide with alkenylphenols.These alkenylphenols are obtained by thermolysis of bisphenol A, alkylation of phenol with cyclopentadiene followed by isomerization, and alkylation of phenol with mesityl oxide followed by thermolysis to give 4-isopropenylphenol, 2- and 4-(cyclopenten-1-yl)phenol, and 2,2,4-trimethyl-1,2-chromene, respectively.
- Dai, S. H.,Lin, C. Y.,Rao, D. V.,Stuber, F. A.,Carleton, P. S.,Ulrich, Henri
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p. 1722 - 1725
(2007/10/02)
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- Oxidations of Cyclopropane, Methylcyclopropane, and Arenes with the Mono-oxygenase System from Methylococcus capsulatus
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The mono-oxygenase system from Methylococcus capsulatus oxidises cyclopropane to cyclopropanol, methylcyclopropane to cyclopropylmethanol, and monosubstituted benzenes to para-substituted phenols (with accompanying NIH shift).
- Dalton, Howard,Golding, Bernard T.,Waters, Barry W.,Higgins, Raymond,Taylor, John A.
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p. 482 - 483
(2007/10/02)
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- Process for producing hydroquinone
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An improved process for producing hydroquinone from p-isopropenyl phenol is disclosed. Hydroquinone is obtained by oxidizing p-isopropenyl phenol with hydrogen peroxide or an organic peroxide as an oxidizing agent at a temperature of 28° to 50° C. in the presence of a strong acid catalyst using a slightly or hardly water-soluble high-boiling polar solvent. In the oxidation reaction, the mole ratio of the oxidizing agent to p-isopropenyl phenol is kept at less than 1. After the reaction, in order to effectively decompose or consume the undecomposed p-isopropenyl phenol hydroperoxide and the unreacted oxidizing agent remaining in the reaction mixture, the reaction mixture is aged. Alternatively, or subsequently to the aging reaction, SO2 is added to the reaction mixture to completely decompose the undecomposed or unreacted peroxide. Thus, hydroquinone of high purity is obtained.
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- Method for waste recovery from a process of the production of diphenylolpropane
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The essence of the invention consists in heating the dian waste in the presence of sodium hypophosphite as a catalyst in amount of 0.01 - 0.5% by weight at a temperature of 150 to 250° C and under reduced pressure in the range of 5 to 50 mm Hg. As a result a destillate is obtained containing as main components phenol, o- and p-isopropenyl-phenol and their dimers at yield of about 40-74% by weight calculated in relation to the initial amount of dian waste. The distillate obtained was made up with fresh phenol or with phenol and acetone and brought into contact with strongly acid cation exchanger, such as Wofatit KPS, Zerolit 225, Wofatit OK-80, in consequence the o- and p-isopropenylphenol and their dimers reacted with phenol to obtain the dian, the latter being then separated by known methods.
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