13269-52-8Relevant articles and documents
CATALYTIC ACTIVITY OF THE PRODUCTS OF LOW-TEMPERATURE COCONDENSATION OF OLEFINS WITH THE VAPORS OF TRANSITION METALS
Vasil'kov, A. Yu.,Zakurin, N. V.,Kogan, A. S.,Sergeev, V. A.,Lisichkin, G. V.
, p. 834 - 838 (1985)
-
METAL COMPLEXES IN CATALYTIC CONVERSION OF OLEFINS. 3. CATALYTIC DIMERIZATION OF ETHYLENE AND PROPYLENE BY Ni(PPh3)n-Et3Al2Cl3 SYSTEM
Furman, D. B.,Kudryashev, A. V.,Ivanov, A. O.,Pogorelov, A. G.,Yanchevskaya, T. V.,Bragin, O. V.
, p. 444 - 447 (1990)
The Ni(PPh3)n-Et3Al2Cl3 catalytic system was found to be most effective for the dimerization of ethylene and propylene when the ligands Bu3PO and (BuO)2-PNEt2 were used in the Ni complex.For propylene dimerization in the liquid phase, the yield was 54 kmole/mole Nih at 40 - 55 deg C.Using mathematical planing methods for the experiments the optimum conditions range for the formation of hexanes was found, in which selectivity for dimerization reached 85-96percent at 80-90percent conversion.
Isomerization of Olefins Catalyzed by the Hexaaquaruthenium(2+) Ion
Karlen, Thomas,Ludi, Andreas
, p. 1604 - 1606 (1992)
Isomerization of olefins, in particular the useful transformation of allyl to vinyl ethers is catalyzed by the hexaaquaruthenium(2+) ion, producing the (E)-isomers under mild conditions.
Rhodium(III) Catalyzed Solvent-Free Tandem Isomerization–Hydrosilylation From Internal Alkenes to Linear Silanes
Azpeitia, Susan,Garralda, María A.,Huertos, Miguel A.
, p. 1901 - 1905 (2017)
The selective synthesis of linear silanes from internal alkenes or alkene mixtures is reported. Unsaturated 16 electrons hydrido–silyl–RhIII complexes are efficient catalysts for a tandem catalytic alkene isomerization–hydrosilylation reaction at room temperature under solvent-free conditions. Such a process would be of value to the chemical industry, as mixtures of internal aliphatic olefins are substantially cheaper and more readily available than the pure terminal isomers.
Catalyst versus Substrate Control of Forming (E)-2-Alkenes from 1-Alkenes Using Bifunctional Ruthenium Catalysts
Paulson, Erik R.,Delgado, Esteban,Cooksy, Andrew L.,Grotjahn, Douglas B.
, p. 1672 - 1682 (2018)
Here we examine in detail two catalysts for their ability to selectively convert 1-alkenes to (E)-2-alkenes while limiting overisomerization to 3- or 4-alkenes. Catalysts 1 and 3 are composed of the cations CpRu(κ2-PN)(CH3CN)+ and Cp?Ru(κ2-PN)+, respectively (where PN is a bifunctional phosphine ligand), and the anion PF6-. Kinetic modeling of the reactions of six substrates with 1 and 3 generated first- and second-order rate constants k1 and k2 (and k3 when applicable) that represent the rates of reaction for conversion of 1-alkene to (E)-2-alkene (k1), (E)-2-alkene to (E)-3-alkene (k2), and so on. The k1:k2 ratios were calculated to produce a measure of selectivity for each catalyst toward monoisomerization with each substrate. The k1:k2 values for 1 with the six substrates range from 32 to 132. The k1:k2 values for 3 are significantly more substrate-dependent, ranging from 192 to 62 000 for all of the substrates except 5-hexen-2-one, for which the k1:k2 value was only 4.7. Comparison of the ratios for 1 and 3 for each substrate shows a 6-12-fold greater selectivity using 3 on the three linear substrates as well as a >230-fold increase for 5-methylhex-1-ene and a 44-fold increase for a silyl-protected 4-penten-1-ol substrate, which are branched three and five atoms away from the alkene, respectively. The substrate 5-hexen-2-one is unique in that 1 was more selective than 3; NMR analysis suggested that chelation of the carbonyl oxygen can facilitate overisomerization. This work highlights the need for catalyst developers to report results for catalyzed reactions at different time points and shows that one needs to consider not only the catalyst rate but also the duration over which a desired product (here the (E)-2-alkene) remains intact, where 3 is generally superior to 1 for the title reaction.
Highly Stereoselective Isomerization of Monosubstituted 1-Alkenes to (E)-2-Alkenes by Catalysis of (C5Me5)2TiCl2/NaC10H8
Akita, Munetaka,Yasuda, Hajime,Nagasuna, Kinya,Nakamura, Akira
, p. 554 - 558 (1983)
The catalyst systems which consist of MCl2(C5R5)2(M=Ti, Zr; R=H, CH3)/NaC10H8, i-C3H7MgBr, n-C4H9Li or LiAlH4 in 1:2 ratio were highly effective for the stereoselective isomerization of monosubstituted 1-alkenes to (E)-2-alkenes.Unconjugated dienes were converted to (E)- or (E,E)-dienes.The catalysis of (C5Me5)TiCl2/NaC10H8 was extremely high and resulted in the complete isomerization of 1-alkenes in >99percent stereoselectivity within a short period.The use of the bulky C5Me5 ligand is essential to find out the excellent stereoselectivity.Systems, (C5H5)2TiCl2/NaC10H8 and (C5H5)2TiCl2/i-C3H7MgBr showed less selectivity and the catalysis of the corresponding zirconium systems was very poor irrespective of the reducing agents and substrates.
Designing bifunctional alkene isomerization catalysts using predictive modelling
Landman, Iris R.,Paulson, Erik R.,Rheingold, Arnold L.,Grotjahn, Douglas B.,Rothenberg, Gadi
, p. 4842 - 4851 (2017)
Controlling the isomerization of alkenes is important for the manufacturing of fuel additives, fine-chemicals and pharmaceuticals. But even if isomerization seems to be a simple unimolecular process, the factors that govern catalyst performance are far from clear. Here we present a set of models that describe selectivity and activity, enabling the rational design and synthesis of alkene isomerization catalysts. The models are based on simple molecular descriptors, with a low computational cost, and are tested and validated on a set of eleven known Ru-imidazol-phosphine complexes and two new ones. Despite their simplicity, these models show good predictive power, with R2 values of 0.60-0.85. Using a combination of principal components analysis (PCA) and partial least squares (PLS) regression, we construct a "catalyst map", that captures trends in reactivity and selectivity as a function of electrostatic charge on the N? atom, EHOMO, polar surface area and the optimal mass substituents on P/distance Ru-P ratio. In addition to indicating "good regions" in the catalyst space, these models also give insight into mechanistic steps. For example, we find that the electrostatic charge on N?, EHOMO and polar surface area are crucial in the rate-limiting step, whereas the optimal mass of substituents on P/distance Ru-P is correlated with the product selectivity.
Living and block copolymerization of ethylene and α-olefins using palladium(II)-α-diimine catalysts
Gottfried, Amy C.,Brookhart
, p. 3085 - 3100 (2003)
Living polymerization of ethylene with palladium(II) diimine complexes coupled with use of a functionalized initiator and/or cleavage of the palladium-polymer bond with various reagents provides a protocol for synthesis of mono- and di-end-functionalized, branched, amorphous polyethylenes. The functional initiator used is the chelate complex [(ArN=C(Me)-C(Me)=NAr)Pd(CH2)3C(O)OMe] [(Bar′4)] (Ar = 2,6-(iPr)2C6 H3) (3). The alkylchain is cleaved by insertion of alkyl acrylates or methyl vinyl ketone, followed by cleavage with Et3SiH to generate alkyl ester or methyl ketone end groups, respectively. Insertion of 5-hexen-1-ol, followed by chain running and β-elimination, results in formation of aldehyde end groups. Conditions for living polymerization of propylene, 1-hexene, and 1-octadecene have also been established. Rates of first monomer insertion and subsequent chain growth are shown to be a sensitive function of the palladium complex used for initiation and the nature and concentration of auxiliary nitrile ligands. Block copolymers of ethylene and 1-octadecene were prepared under living conditions. The copolymers microstructure differed depending on the order of introduction of the blocks.
Magoon,Slaugh
, p. 4509,4514 (1967)
-
Smith,Gilde
, p. 5325,5328 (1959)
-
SOME FEATURES OF THE ISOMERIZATION OF α-OLEFINS IN THE PRESENCE OF HETEROGENIZED NICKEL COMPLEXES
Furman, D. B.,Volchkov, N. V.,Makhlis, L. A.,Chernov, S. A.,Vasserberg, V. E.,Bragin, O. V.
, p. 509 - 513 (1983)
-
Zweifel,Steele
, p. 5085 (1967)
Novel nickel nanoparticles stabilized by imidazolium-amidinate ligands for selective hydrogenation of alkynes
López-Vinasco, Angela M.,Martínez-Prieto, Luis M.,Asensio, Juan M.,Lecante, Pierre,Chaudret, Bruno,Cámpora, Juan,Van Leeuwen, Piet W. N. M.
, p. 342 - 350 (2020/02/04)
The main challenge in the hydrogenation of alkynes into (E)- or (Z)-alkenes is to control the selective formation of the alkene, avoiding the over-reduction to the corresponding alkane. In addition, the preparation of recoverable and reusable catalysts is of high interest. In this work, we report novel nickel nanoparticles (Ni NPs) stabilized by three different imidazolium-amidinate ligands (ICy·(Ar)NCN; L1: Ar = p-tol, L2: Ar = p-anisyl and L3: Ar = p-ClC6H4). The as-prepared Ni NPs were fully characterized by (HR)-TEM, XRD, WASX, XPS and VSM. The nanocatalysts are active in the hydrogenation of various substrates. They present a remarkable selectivity in the hydrogenation of alkynes towards (Z)-alkenes, particularly in the hydrogenation of 3-hexyne into (Z)-3-hexene under mild reaction conditions (room temperature, 3% mol Ni and 1 bar H2). The catalytic behaviour of Ni NPs was influenced by the electron donor/acceptor groups (-Me, -OMe, -Cl) in the N-aryl substituents of the amidinate moiety of the ligands. Due to the magnetic character of the Ni NPs, recycling experiments were successfully performed after decantation in the presence of an external magnet, which allowed us to recover and reuse these catalysts at least 3 times preserving both activity and chemoselectivity.
Potassium Yttrium Ate Complexes: Synergistic Effect Enabled Reversible H2 Activation and Catalytic Hydrogenation
Zhai, Dan-Dan,Du, Hui-Zhen,Zhang, Xiang-Yu,Liu, Yu-Feng,Guan, Bing-Tao
, p. 8766 - 8771 (2019/09/30)
A potassium yttrium benzyl ate complex was generated simply by mixing an yttrium amide and potassium benzyl. The benzyl ate complex could undergo peripheral deprotonation to produce a cyclometalated complex or hydrogenation to give a hydride ate complex. The latter hydride ate complex features a (KH)2 structure protected by two yttrium amide complexes. The synergistic effect between potassium hydride and the amide ligand enables the complex to deprotonate a methyl C-H bond. The combination of intramolecular deprotonation of the hydride ate complex and hydrogenation of the cyclometalated complex constitutes a reversible H2 activation process. Using this process involving formal addition and elimination of H2, we accomplished the catalytic hydrogenation of alkenes, alkynes, and imines.