4050-45-7Relevant articles and documents
UTILIZATION OF SUPERCRITICAL FLUID SOLVENT-EFFECTS IN HETEROGENEOUS CATALYSIS.
Tiltscher,Wolf,Schelschshorn
, p. 897 - 900 (1984)
Comparative studies on fixed-bed catalytic isomerization of 1-hexene and disproportionation of 1,4-diisopropylbenzene were performed under liquid, gaseous or supercritical conditions. The kinetic measurements show that by variation of pressure in the different fluid states catalytic surface reactions as well as mass transfer effects between catalyst and fluid phase and/or transport processes inside porous catalysts can be influenced in a very sensitive way. Conclusions are drawn in view of new possibilities for the direction of yield and selectivity of multiple reactions, for the prolongation of catalyst lifetime, and the study of deactivation mechanisms on heterogeneous catalysts.
METAL COMPLEXES IN THE CATALYTIC TRANSFORMATIONS OF OLEFINS. 5. CATALYTIC SYNTHESIS OF C9-C24 OLEFINS FROM PROPYLENE
Furman, D. B.,Ivanov, A. O.,Belyankin, A. Yu.,Pogorelov, A. G.,Yanchevskaya, T. V.,Bragin, O. V.
, p. 1011 - 1014 (1992)
The optimum conditions for the production of C9-C24 olefins with yields of 20-25percent (remainder hexenes) by oligomerization of liquid propylene at the Ni(PPh3)n (n = 2-4)-Et3Al2Cl3 catalytic system were determined by simplex design of experiments.It was shown that the obtained hexenes undergo secondary di- and trimerization reactions.Key words: oligomers, propylene, triphenylphosphinenickel, triethylaluminum.
Microporous Heteropoly Compound as a Shape Selective Catalyst: Cs2.2H0.8PW12O40
Okuhara, Toshio,Nishimura, Toru,Misono, Makoto
, p. 155 - 156 (1995)
The pore size of acidic Cs salts (CsxH3-xPW12O40) was precisely controlled by the Cs content.Cs2.2H0.8PW12O40 possesses micropores in the range from 6.2 to 7.5 Angstroem (in diameter) and exhibits efficient shape selective catalysis toward decomposition of ester, dehydration of alcohol, and alkylation of aromatics in liquid-solid system.This is the first example of shape-selective solid superacid.
The catalytic effect of boron substitution in MCM-41-type molecular sieves
Sundaramurthy,Eswaramoorthi,Lingappan
, p. 631 - 640 (2004)
A series of B-MCM-41 samples has been synthesized with a wide range of boron content (SiO2:B2O3 ratio from 20 to 200), using ethyl silicate ester-40 (ES-40) as the silica source and characterized by XRD, BET, FT-IR, 11B-MAS NMR, SEM, pyridine adsorption, TPDA, and chemical analysis. The interplanar d100 spacing varies from 40 to 45 A, depending on the Si:B ratio. On calcination, a significant amount of four-coordinated boron is converted into less stable three-coordinated boron, and some boron is removed from the framework. The degree of deboronation increases with an increase of boron content of the sample. The B substitution in the MCM-41 framework results in only weak and mild acid sites. The isomerization of 1-hexene is found to be influenced by the boron content in the framework. The isomerization leads to both a hydrogen shift and skeletal rearrangement. The selectivity ratios of cis-2-hexene to trans-2-hexene and 2-hexene to 3-hexene were found to decrease with an increase of temperature and a decrease of the SiO2:B2O3 ratio of the catalysts. Skeletal isomerization starts at 250°C, forming secondary products, and increases with an increase of temperature and an increase of boron content of the catalysts.
Exohedral functionalization: Vs. core expansion of siliconoids with Group 9 metals: Catalytic activity in alkene isomerization
Giarrana, Luisa,Huch, Volker,Poitiers, Nadine E.,Scheschkewitz, David,Zimmer, Michael
, p. 7782 - 7788 (2020)
Taking advantage of pendant tetrylene side-arms, stable unsaturated Si6 silicon clusters (siliconoids) with the benzpolarene motif (the energetic counterpart of benzene in silicon chemistry) are successfully employed as ligands towards Group 9 metals. The pronounced σ-donating properties of the tetrylene moieties allow for sequential oxidative addition and reductive elimination events without complete dissociation of the ligand at any stage. In this manner, either covalently linked or core-expanded metallasiliconoids are obtained. [Rh(CO)2Cl]2 inserts into an endohedral Si-Si bond of the silylene-functionalized hexasilabenzpolarene leading to an unprecedented coordination sphere of the Rh centre with five silicon atoms in the initial product, which is subsequentially converted to a simpler derivative under reconstruction of the Si6 benzpolarene motif. In the case of [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) a similar Si-Si insertion leads to the contraction of the Si6 cluster core with concomitant transfer of a chlorine atom to a silicon vertex generating an exohedral chlorosilyl group. Metallasiliconoids are employed in the isomerization of terminal alkenes to 2-alkenes as a catalytic benchmark reaction, which proceeds with competitive selectivities and reaction rates in the case of iridium complexes.
Komplexkatalyse XXIX. Kationische Allylbis(ligand)nickel(II)hexafluorophosphate PF6 und die Kombination /Et2AlCl als Katalysatoren fuer die Propendimerisation
Balbolov, Entscho,Mitkova, Magdalena,Kurtev, Kurty,Gehrke, Joerg-Peter,Taube, Rudolf
, p. 247 - 256 (1988)
The cationic allylbis(ligand)nickel(II) complexes PF6 with L=P(OPh)3, P(OThym)3 and SbPh3 were found to be efficient catalysts for the oligomerization of propene under a l0 bar pressure of the monomer.The main products are dimers, and specifically the methylpentenes.The /Et2AlCl system catalyzes propene dimerization at atmospheric pressure with high activity, and selectivity similar to that of the cationic allylbis(ligand)nickel(II) complexes.In a kinetic analysis the rate law and the activation parameters ΔH and ΔS were determined for the propene dimerization with this catalytic system.
Kovacs et al.
, p. 412,413, 414 (1970)
-
Lewina et al.
, p. 690,691;engl.Ausg.S.727 (1950)
-
Alkylation of toluene with 1-hexene over macroreticular ion-exchange resins
Cadenas, Madelin,Bringué, Roger,Fité, Carles,Iborra, Montserrat,Ramírez, Eliana,Cunill, Fidel
, p. 143 - 148 (2014)
The macroreticular acidic ion-exchange resins Amberlyst 35, Amberlyst 46 and Purolite CT 275 were investigated as catalysts for the alkylation of toluene with 1-hexene and simultaneous dimerization and isomerization of the olefin at 373 K. After six hours
Allylnickel(II) complexes of bulky 5-substituted-2-iminopyrrolyl ligands
Cruz, Tiago F. C.,Gomes, Pedro T.,Lopes, Patrícia S.
, (2021/08/05)
The optimized reaction between [Ni(COD)2] (COD = 1,5-cyclooctadiene) and ligand precursor 5-(2,4,6-triisopropylphenyl)-2-[N-(2,6-diisopropylphenyl)-formimino]-1H-pyrrole yielded the η3-cyclooctenyl-Ni(II) complex [Ni{κ2N,N’-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H) = N(2,6-iPr2C6H3)}(η3-C8H13)] 1. Subsequently, the η3-allyl complexes [Ni{κ2N,N’-5-R-NC4H2-2-C(H)=N(2,6-iPr2C6H3)}(η3-C3H5)] (R = 3,5-(CF3)2C6H3 (2a), 2,6-Me2C6H3 (2b), 2,4,6-iPr3C6H2 (2c) and CPh3 (2d)) were prepared in good yields via metathesis of [Ni(η3-C3H5)(μ-Br)]2 with the respective potassium 5-R-2-[N-(2,6-diisopropylphenyl)formimino]pyrrolyl salt (KLa-d). Complexes 1 and 2a-d were characterized by NMR spectroscopy, elemental analysis and complex 2d further analyzed by single crystal X-ray diffraction. Addition of excess pyridine to solutions of complexes 2a-d led to the observation of a fluxional process that, according to VT-NMR experiments, corresponds to a pyridine-assisted cis–trans isomerization process occurring in these complexes, via a η3-η1-η3 haptotropic shift of the allyl ligand, with ΔG? values in range of 9.5–17.3 kcal mol?1. Additionally, complexes 2a-d, when activated by B(C6F5)3, slowly catalyzed the isomerization of hex-1-ene to mixtures of internal olefins.
Immobilized Platinum Hydride Species as Catalysts for Olefin Isomerizations and Enyne Cycloisomerizations
Bauer, Matthias,Cronin, Steve P.,Dyballa, Michael,Estes, Deven P.,Li, Zheng,Maier, Sarah,Nowakowski, Michal,Vu Dinh, Manh-Anh
supporting information, p. 1751 - 1757 (2021/06/28)
Platinum hydride species catalyze a number of interesting organic reactions. However, their reactions typically involve the use of high loadings of noble metal and are difficult to recycle, making them somewhat unsustainable. We have synthesized surface-immobilized Pt-H species via oxidative addition of surface OH groups to Pt(PtBu3)2 (1), a rarely used immobilization technique in surface organometallic chemistry. The hydride species thus made were characterized by infrared, magic-angle spinning nuclear magnetic resonance, and X-ray absorption spectroscopies and catalyzed both olefin isomerization and cycloisomerization of a 1,6 enyne (5) with a high selectivity and low Pt loading.
