- [2+2] Photocycloaddition of symmetrically disubstituted alkenes to 2(5H)-furanones: Diastereoselective entry to 1,2,3,4-tetrasubstituted cyclobutanes
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A study on the [2+2] photochemical cycloaddition of 1,4-difunctionalized 2-butenes to 2(5H)-furanones is presented. These reactions deliver 1,2,3,4-tetrasubstituted cyclobutanes with suitable functionalization in the four side chains for further synthetic elaboration. The effects of the substituents in both the lactone and the 2-butene on the stereoselectivity of the photochemical reaction have been evaluated. Starting from (Z)-2-butenes, under photosensitized conditions, a competitive cis/trans isomerization of the olefin inhibits the cycloaddition process. It was found that the presence of a cis double bond confined within a medium-size ring does not prevent bond rotation in the intermediate 1,4-biradicals. Copyright
- Pares, Sonia,De March, Pedro,Font, Josep,Alibes, Ramon,Figueredo, Marta
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- Catalytic conversions of chloroolefins over iron oxide nanoparticles: 1. Isomerization of dichlorobutenes in the presence of iron oxide nanopaticles immobilized on silicas with different structures
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The influence of the support nature and electronic state of iron oxide nanoclusters on the catalytic properties of supported systems was studied for dichlorobutene isomerization. A sample with a Fe content of 2.5 wt.% on the activated silica matrix containing FeIII and FeII ions in the paramagnetic state exhibits the highest activity. The activity of iron on silica gel enhances with the appearance of magnetically ordered nanoclusters of γ-iron oxide formed at the iron content on the catalyst as high as 15 wt.%. An increase in the catalyst activity is favored by the formation of two states of iron (FeIII and FeII) that occurs under the synthesis conditions or during the action of a reactant.
- Rostovshchikova,Smirnov,Tsodikov,Bukhtenko,Maksimov,Kiseleva,Pankratov
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- Catalytic conversions of chloroolefins over iron oxide nanoparticles 2. Isomerization of dichlorobutenes over iron oxide nanoparticles stabilized on the surface of ultradispersed poly(tetrafluoroethylene)
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Nanosized iron oxides stabilized on the surface of ultradispersed poly(tetrafluoroethylene) (UPTFE) granules were synthesized by the thermal destruction of iron formate in boiling bed of UPTFE on the surface of heated mineral oil. The particle size of nanoparticles (～6 nm) containing 5, 10, and 16 wt.% Fe depends weakly on the temperature of synthesis and iron to polymer ratio. The metal state is determined by the synthesis conditions. The nanoparticles synthesized at 280°C consist mainly of the Fe 3O4 and Fe2O3 phases. The samples obtained at 320°C also contain iron(II) oxide. The catalytic properties of the obtained samples were tested in dichlorobutene isomerization. Unlike isomerization on the iron oxide nanoparticles supported on silica gel, reaction over the UPTFE supports proceeds without an induction period. The sample with 10 wt.% Fe containing magnetically ordered γ-Fe2O3 nanoparticles possesses the highest catalytic activity. Fast electron exchange between the iron ions in different oxidation states and high defectiveness of the nanoparticles contribute, most likely, to the catalytic activity.
- Rostovshchikova,Korobov,Pankratov,Yurkov,Gubin
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- Kinetics of inversion of dichlorobutene in the heterogeneous system
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The reaction kinetics of the isomerization of 3,4-dichlorobutene-1 to 1,4-dichlorobutene-2 was investigated by using gas-liquid chromatography in presence of Fe2O3/ZrO2 as solid catalyst. At the optimizing conditions, the catalytic activity, rate constants of reaction and activation energy have been evaluated using kinetic equations. The structure of the catalyst was investigated by using Mossbauer spectroscopy.
- Langeroodi, N. Samadani
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experimental part
p. 2772 - 2774
(2012/08/28)
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- Isomerization of 3,4-dichloro-1-butene into 1,4-dichloro-2-butene by heterogeneous catalysis
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The isomerization of 3,4-dichloro-1-butene into 1,4-dichloro-2-butene was investigated by gas-liquid chromatography in the temperature range of 60-90 °C. Fe2O3/TiO2 was used as a catalyst. Fe2O3/TiO2 solid acid catalyst has been prepared by the support saturation method, tested in the isomerization of 3,4-dichloro-l-butene into 1,4-dichloro-2-butene. This catalyst shows a high activity opposite to pure titania in this reaction. The present investigation focuses on the reactivity of titatia supported ferric oxide with iron contents of 5 wt%. in the isomerization of 3,4-dichloro-lbutene into 1,4-dichloro-2- butene. The activation parameters have been evaluated under optimized conditions, using the Arrhenius and Eyring plots.
- Langeroodi, Narges Samadani
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experimental part
p. 125 - 128
(2011/10/05)
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- Catalytic conversions of chloroolefines over iron oxide nanoparticles 3. Electronic and magnetic properties of γ-Fe2O3 nanoparticles immobilized on different silicas
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Catalytic properties of superparamagnetic γ-ferric oxide nanoclusters, which are uniform in terms of size and magnetic properties were studied. The catalysts were supported on the activated silica gel matrix (AGM) prepared from the KSK-2 silica gel of globular structure and on the activated silica matrix (ASM) prepared from layered natural vermiculite. The clusters are active in some reactions of chloroolefin conversions: isomerization of dichlorobutenes and alkylation of benzene with allyl chloride. Their activity in these reactions is many times higher that of usual supported catalysts based on α-ferric oxide. Analysis of the Moessbauer spectra of the 2.5 wt.% Fe/AGM and 2.5 wt.%Fe/ASM samples before and after the reaction at T = 3-300 K shows that during the reaction some FeIII ions arranged in ～2-3-nm γ-Fe2O3 nanoclusters magnetically ordered at 6 K are reduced to form a high-spin FeII complex in the paramagnetic state. According to the macroscopic magnetization data (SQUID) of the initial clusters, curves with hysteresis are observed at 2 K in the plots of forward and backward magnetization, while the 2.5 wt.%Fe/ASM catalyst after the reaction at T = 2 K demonstrates a linear field dependence of the magnetization passing through the coordinate origin. Analysis of the Moessbauer spectra and magnetic properties suggests that during the catalytic reaction the Fe III ions in the γ-Fe2O3 nanoclusters interact with chloroolefin with the allylic structure to be partially reduced to the FeII ions that are bound in a complex containing chloride ions and OII ion(s) of the silicate matrix as ligands. This is a reason, probably, for the high catalytic activity of γ-Fe2O3 nanoparticles.
- Rostovshchikova,Kiseleva,Smirnov,Maksimov,Suzdalev,Prusakov,Tsodikov,Ikorskii
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p. 1768 - 1774
(2008/02/05)
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- Gas-sensitive and catalytic properties of ensembles of interacting palladium nanoparticles
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The electrophysical and catalytic properties of poly(p-xylylene) materials containing palladium nanoparticles are studied. It is shown that an ensemble of interacting nanoparticles is formed, whose conductivity exhibits a high sensitivity to gas adsorption. This structure also shows unusual catalytic properties.
- Vorontsov,Gerasimov,Golubeva,Grigor'ev,Zav'yalov,Zav'yalova,Trakhtenberg
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p. 1742 - 1744
(2007/10/03)
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- CATALYSIS OF DICHLOROBUTENE ISOMERIZATION BY HETEROVALENT COPPER COMPLEXES. I. FORMATION OF POLYNUCLEAR COPPER(I,II) COMPLEXES IN THE SYSTEM TRIPHENYLPHOSPHINE-COPPER CHLORIDE-3,4-DICHLORO-1-BUTENE
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The processes occurring in the system triphenylphosphine-copper chloride-3,4-dichloro-1-butene in the presence of O2 at 100 deg C and resulting in the formation of copper heterovalent complexes were studied by ESR, 31P NMR, UV and IR spectroscopy, and chromatography.The resulting complexes catalyze isomerization of 3,4-dichloro-1-butene into trans-1,4-dichloro-2-butene.The maximum catalytic activity was displayed by the copper complex of the tetrameric composition with the ratio Cu(I)/Cu(II) ca. 3.
- Rostovshchikova, T. N.,Pergushov, V. I.
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- CATALYSIS OF DICHLOROBUTENE ISOMERIZATION BY HETEROVALENT COPPER COMPLEXES. II. ROLE OF MIXED-LIGAND POLYNUCLEAR COPPER(I,II) COMPLEXES
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Liquid-phase isomerization of dichlorobutene at 80-100 deg C in the presence of copper chloride complexes with triphenylphosphine was studied.When Cu4Cl4(PPh3)4 is used as a catalyst in the presence of atmospheric oxygen, the kkinetic curves show an induction period.The process is accelerated due to formation of a heterovalent intermediate polynuclear complex with participation of dichlorobutene and oxygen molecules.
- Rostovshchikova, T. N.,Pergushov, V. I.
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p. 887 - 891
(2007/10/02)
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- SYNTHESIS OF 11- AND 12-MEMBERED RINGS BY A DIRECT CYCLIZATION METHOD
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The malonate anion intramolecular displacement of propargylic or allylic chlorides, and of primary bromide, in eleven- and twelve-carbon chains containing either two, one, or no unsaturation centers leads to the corresponding 11- and 12-membered ring compounds in good yields under conditions of medium dilution.
- Brillon, Denis,Deslongchamps, Pierre
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- ELECTROCHEMICAL CHLORINATION OF BUTADIENE
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An Electrochemical chlorination of butadiene was investigated at 25 deg C by using an H-type cell with a CoCl2-MeCN anolyte and an NH4Cl-H2O catholyte separated by an anion-exchange membrane.The electrolysis gave 3,4-dichloro-1-butene and trans-1,4-dichloro-2-butene in high current efficiencies.
- Takasu, Yoshio,Matsuda, Yoshiharu,Shimizu, Akinori,Morita, Masayuki,Saito, Mitsutaka
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p. 1685 - 1686
(2007/10/02)
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- Three-Component Reactions. IX. Methoxychlorination of Butadiene. 1. Composition of Reaction Mixtures Obtained Using Either an Excess of Butadiene or an Excess of Chlorine
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Methoxychlorination of butadiene with 2 mol chlorine gives saturated secondary addition products 5-15, which were found identical with methoxychlorination products of unsaturated primary addition products 1-4 (investigated by capillar GLC). 1,2 and 3 add chlorine and methanol with high regioselectivity (80-90percent); meso and erythro isomer predominate in MARKOVNIKOV products from 1 and 2 (87percent diastereoselectivity). 5-7 and 11-15 were separated by preparative GLC for structural analysis.
- Beger, J.,Schiefer, H.,Movsumzade, M.M.,Gurbanov, P.A.
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p. 599 - 609
(2007/10/02)
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- Process for working up liquid copper-containing catalyst waste from isomerization reactions of dichlorobutene
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Improved working up of the waste from an isomerization reaction of dichlorobutene by precipitating the copper catalyst used in said process by adding a polar solvent and removing the resulting precipitate by filtration.
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- Microbiocidal mixtures of polymeric quaternary ammonium compounds
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Bactericidal products comprising mixtures of polymeric quaternary ammonium compounds which are the condensation products of 1,4-dihalo-2-butene and a difunctional tertiary amine of the type STR1 wherein Z consists of from one to three aliphatic radicals of 2 to 10 carbon atoms, each aliphatic radical containing 0 to 2 double bonds and 0 to 2 hydroxy substituents; and wherein R' and R may be either the same or different and may be either (a) primary or secondary alkyls having from 1 to 20 carbon atoms with a total sum of no greater than 36 carbon atoms, (b) hydroxy or dihydroxy derivatives of the aforesaid primary or secondary alkyls, (c) benzyl, (d) alkyl-benzyl, or (e) combined with N to form a heterocyclic group of either 5, 6 or 7 atoms.
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