110-57-6Relevant articles and documents
[2+2] Photocycloaddition of symmetrically disubstituted alkenes to 2(5H)-furanones: Diastereoselective entry to 1,2,3,4-tetrasubstituted cyclobutanes
Pares, Sonia,De March, Pedro,Font, Josep,Alibes, Ramon,Figueredo, Marta
, p. 3888 - 3895 (2011)
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
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
Rostovshchikova,Smirnov,Tsodikov,Bukhtenko,Maksimov,Kiseleva,Pankratov
, p. 1418 - 1424 (2005)
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.
Catalytic conversions of chloroolefins over iron oxide nanoparticles 2. Isomerization of dichlorobutenes over iron oxide nanoparticles stabilized on the surface of ultradispersed poly(tetrafluoroethylene)
Rostovshchikova,Korobov,Pankratov,Yurkov,Gubin
, p. 1425 - 1432 (2005)
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.
Kinetics of inversion of dichlorobutene in the heterogeneous system
Langeroodi, N. Samadani
experimental part, p. 2772 - 2774 (2012/08/28)
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.
Catalytic conversions of chloroolefines over iron oxide nanoparticles 3. Electronic and magnetic properties of γ-Fe2O3 nanoparticles immobilized on different silicas
Rostovshchikova,Kiseleva,Smirnov,Maksimov,Suzdalev,Prusakov,Tsodikov,Ikorskii
, p. 1768 - 1774 (2008/02/05)
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.
