Dimerization Of Propylene Research Articles

Oxidative dimerisation of propene to 1,5-hexadiene on Bi-Zn-O catalysts

The oxidative dimerisation of propene to 1,5-hexadiene has been investigated on Bi-Zn-O catalysts. The Bi48ZnO73 phase, observed in the catalysts calcined at 700 ° C is an active and selective catalyst for the formation of 1,5-hexadiene. The best catalytic performance (1,5-hexadiene selectivity ≈ 64%) has been obtained at 525 ° C, with a propene to oxygen ratio of 26, on a catalyst formed by Bi48ZnO73 with a small excess of ZnO.

Nature of catalytic effect of Ni(O)- and BF3OEt2-based systems in propene dimerization

1H NMR, EPR and IR spectroscopic studies of the products of the interaction between components of the Ni[PPh3]4+EtOH+BF3.OEt2 and Ni(PPh3)4+BF3OEt2 systems suggest the formation of two types of complexes [HNi(PP3)3L]+[BF3OEt]− and [Ni(PPh3)3L]+BF4−, which are catalytically active in propene dimerization.

プロピレンの酸化脱水素芳香族化反応におけるＢｉ‐Ｃｅ‐Ｏ系触媒の触媒挙動および反応機構

パルス法で本反応におけるBi2O3,CeO2およびBi-Ce-O系触媒の特性を調べ,Bi-Ce-O触媒はベンゼン生成に有効であることを見いだした。Bi2O3触媒では主な二量化生成物は1-5-ヘキサジエンであるが,CeO2触媒ではベンゼンまで環化し,活性低下が激しく,触媒表面近傍の格子酸素のみ利用すると思われる。一方,Bi2O3とCeO2の複合化により,触媒内部に収着した酸素(α 酸素)が多量に生成し,格子酸素が補償されるため,芳香族化選択性が向上すると思われる。Bi-Ce-O系触媒上での速度論的検討により,二量化反癒は完全酸化反応と異なったサイトで併発し,その律速段階は,プロピレンの気相分子と吸着分子との(Eley-Rideal型)反応によると考えられる。

Metal complexes in catalytic conversion of olefins. 3. Catalytic dimerization of ethylene and propylene by Ni(PPh3)n-Et3Al2Cl3 System

The Ni(PPh3)n-Et3Al2Al3 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 Ni-h at 40–55‡C. Using mathematical planning methods for the experiments the optimum conditions range for the formation of hexanes was found, in which selectivity for dimerization reached 85–96% at 80–90% conversion.

Catalytic dimerization of alkenes by nickel complexes in organochloroaluminate molten salts

Organochloroaluminate molten salts based on aluminium trichloride or ethylaluminium dichloride and 1-methyl-3-butylimidazolium chloride, 1-butylpyridinium chloride or tetrabutylphosphonium chloride can be used as solvents for the catalytic dimerization of propene to hexenes isomers by nickel complexes.

プロピレン二量化による２，３‐ジメチルブテン（ＤＭＢ）製造技術の開発と工業化に関する研究

2, 3-Dimethylbutene-2 (DMB-2) is a key olefin for the synthesis of Danitol®, which is a high perfomance pyrethroid insecticide invented by Sumitomo in 1976. At that time, DMB-2 was too expensive for the development of Danitol®. Therefore, we studied the simplest way to DMB-2, that is, the dimerization of propylene to DMB-1 followed by isomerization to DMB-2, and succeeded in developing the efficient dimerization catalyst. This catalyst consists of six components ; nickel naphthenate (Ni (naph)2) /PR3/diene/AlEt3/chlorinated phenol/ H2O. The characteristics of this catalyst are as follows. (1) The content of DMBS in dimers (DMBS selectivity) is high as 86%. (2) DMB-1 and DMB-2 can be produced at will only by controlling the molar ratio of catalyst components. (3) A small amount of water enhances the catalytic activity remarkably. Using this catalyst, we started the commercial production of DMB-2 in 1983.

ChemInform Abstract: Catalytic Dimerization of Ethylene and Propylene by (η6‐Arene)NiR2 and in Combination with Alkylaluminum Halides. Production of Highly Active Homogeneous Catalysts.

AbstractIn order to gain evidence for catalytically active intermediates and evidence regarding the role of the cocatalyst the new class of Ni‐complexes (I) and their Co analogues are examined for activity as homogeneous catalysts for ethylene and propylene dimerization.

Propylene dimerization over silica-supported N1(1) complexes: electronic and steric effect of the trialkylphosphine ligand

Catalytic properties of a set of silica-supported Ni(I) complexes are compared for propylene dimerization at 313 K and in the pressure range 1 – 6 bar. From EPR studies a reaction pathway involving the concerted coupling of two propylene molecules on each Ni(I) site is proposed. The EPR characterization of the metallacyclic intermediate is reported. This mechanism is in agreement with the hexene distribution observed at low propylene conversion. The presence of one trialkylphosphine ligand in the Ni(I) coordination sphere has both electronic and steric influences: (i) by an electron-donating effect, it increases the stability of the active sites (poisoned by heavy oligomers in the trialkylphosphine free catalysts) and the selectivity for α-hexenes (with P(c-C 6H 11) 3, at a conversion of 5%, 57% of α-hexenes are obtained). (ii) by a steric effect, it modifies the hexene distribution. Bulky ligands such as Pcy 3 increase the selectivity for 2,3 dimethylbutenes to 35%, while the selectivity for linear hexenes decreases to 8%. The turnover rates, of ~3.5 × 10 −2 s −1 (Ni(I)) −1 are convenient for heterogeneous catalysts.

Catalytic dimerization of ethylene and propylene by (.eta.6-arene)NiR2 and in combination with alkylaluminum halides. Production of highly active homogeneous catalysts

Catalytic dimerization of ethylene and propylene by (.eta.6-arene)NiR2 and in combination with alkylaluminum halides. Production of highly active homogeneous catalysts

Preparation and characterization of silica-supported propylene dimerization catalysts: Ni(I) trialkylphosphine complexes

Trialkylphosphines (TAP) are able to reduce silica-supported unsaturated Ni(II) cations selectively into Ni(I) at room temperature. This chemical reduction is very convenient because it leads to high amounts of Ni(I) while affording the required ligands to build the propylene oligomerization active entity. The highest reduction degree (60%) is achieved with low nickel content exchanged silicas (τ < 2% (w/w)) mainly constituted of isolated three-coordinate Ni(II) cations before reduction. In high nickel content samples, the presence of Ni(II) paired through an oxygen bridge seems to limit reduction by TAP as well as photoreduction. The preparation of Ni I(PR 3) n ( n = 1,2, 3, 4 when R = CH 3 or C 5H 5, and n = 1, 2, 3 when R = c-C 6H 11or C 6H 5) is reported. EPR and reflectance spectroscopy parameters of the complexes are given as well as some molecular models. From the IR study, two types of hydrogen bond between the trialkylphosphine and the surface hydroxyl groups are evidenced: (i) one is reversibly formed between the phosphorus doublet of TAP adsorbed on the support and a hydrogen atom of a surface OH group; only P(c-C 6H 11) 3 is basic enough to lead to phosphonium ions. (ii) the other occurs between the alkyl groups of the TAP bonded to the Ni(I) and the surface hydroxyl groups, and could thus explain the distorted symmetry of the unsaturated complexes.

Komplexkatalyse: XXIX. Kationische allylbis(ligand)nickel(II)-hexafluorophosphate [C 3H 5NiL 2]PF 6 und die kombination [C 3H 5Ni(Br)P(OThym) 3l/Et 2AlCl als katalysatoren für die propendimerisation

The cationic allylbis(ligand)nickel(II) complexes [C 3H 5NiL 2]PF 6 with L = P(OPh) 3, P(OThym) 3 and SbPh 3 were found to be efficient catalysts for the oligomerization of propene under a 10 bar pressure of the monomer. The main products are dimers, and specifically the methylpentenes. The [C 3H 5Ni(Br)P-(OThym 3]/Et 2AlCl system catayzes 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 Δ H ≠ and Δ S ≠ were determined for the propene dimerization with this catalytic system.

Formation mechanism and structure of compounds catalytically active in propylene dimerization and formed in Pd(acac)2−PR3−BF3OEt2 systems

The interaction between the components of catalytic Pd(acac)2−PR3−BF3OEt2 systems dimerizing propylene to linear hexenes with 59 % selectivity, has been studied by UV and1H NMR spectroscopy methods. Formation mechanism of catalytically active [R3P−Pd−H]+BF 4 − compounds is suggested.

The oxidative coupling of methane

The oxidative coupling of methane to C2 hydrocarbons was studied over a Bi2O3−P2O5−K2O catalyst. Catalysts containing Bi and P are known to be active and selective catalysts for the oxidative dimerization of propylene to 1,5-hexadiene. This catalyst system was found to also be active and selective for the oxidative coupling of methane. The experimental results are interpreted in terms of a dual-site, redox model. Methane activation to form CH3. is proposed to occur on Bi sites. The Bi site is subsequently reoxidized by bulk oxide ions and P becomes the oxygen “inlet” site. Adsorbed surface oxygen species reduce the selectivity to C2 hydrocarbons.

ChemInform Abstract: Dimerization of Ethylene and Propylene Catalyzed by Transition Metal Complexes

ChemInform Abstract: Dimerization of Ethylene and Propylene Catalyzed by Transition Metal Complexes

Dimerization and metathesis of propylene over unsupported oxides of rhenium and tungsten: the metal-insulator transition

Ultraviolet photoemission spectra (UPS) of single crystals of WO 3 and ReO 3 containing propylene were taken to investigate the origin of the selectivity of catalytic reactions over those oxides. The spectra are very similar, suggesting that the selectivity is not attributable to a difference in the distribution of related electronic states and that it originates from a dynamic property of electrons. To investigate a mechanism of metathesis, propylene was reacted over unsupported reduced WO 3 under various pressures and also over unsupported WO 2.

Dimerization of ethylene and propylene catalyzed by transition-metal complexes

Dimerization of ethylene and propylene catalyzed by transition-metal complexes

Linear dimerization of propylene and 1-butene catalyzed by (η 3-4-cyclooctene-1-yl)- (1,1,1,5,5-hexafluoro-2,4-pentanedionato)nickel

The dimerization and oligomerization of propylene and 1-butene in the presence of homogeneous Group VIII transition metal catalysts has been extensively studied. In most cases the products obtained are mixtures of isomers in which branched species predominate, in accordance with preferred anti-Markownikov addition pathways. In what is perhaps the most well-defined catalyst system to date, a family of substituted fluoroacetylacetonate cyclooctenyl nickel complexes, 1-butene is oligomerized to up to 82% linear octenes. Propylene and 1-butene are dimerized to predominantly normal alkenes using homogeneous hydrocarbon solutions of (η 3-4-cyclooctene-1-yl)(1,1,1,5,5,5-hexafluoro)-2,4-pentanedionato)nickel. Two disadvantages of this catalyst system are its relatively low activity and rapid deactivation on storage. In this paper, an improved synthesis of the catalyst is reported, in addition to a method of catalyst storage which virtually eliminates deactivation A comprehensive olefin dimerization reaction scheme is formulated on the basis of detailed gas chromatographic analyses of propylene and 1-butene dimers. The relative amounts of the materials identified allow conclusions to be drawn on relative rates for the competing olefin insertion, β-elimination pathways.

Gel-immobilized catalytic systems for propylene dimerization containing organophosphorus ligands

Catalytic dimerization of propylene in the presence of macromolecular nickel complexes containing organophosphorus ligands has been studied. It has been established that the substitution of alkoxy groups of phosphorus atoms in the polymeric ligands does not affect the dimer composition but permits, within certain limits, to control catalyst activity.

Elimination versus displacement reactions: An alternative mechanistic interpretation of ‘the anomalous reactions of f-propene dimers with thiolate ions’

In 1979 Ishikawa and Maruta reported experimental studies of the reaction of two F -propene dimers, the F -2- and 4-methyl-2-pentenes with thiolate ions. Highly unexpected products, the mercapto derivatives of F -4-methyl-1,3-pentadiene, were isolated. These authors proposed a novel mechanism which included the unprecedented 1,4-elimination of a sulfenyl fluoride from a fluorinated thioether. In the current paper the energetics of this reaction are explicitly discussed and an alternative, more precedented, mechanism is offerred.

Liquid-phase codimerization of ethylene with propylene on nickel carbonyl triphenylphosphine complex anchored on surface of aluminum oxide

1. The catalytic system Ni(CO)x(PPh3)y/A12O3-Et3Al2Cl3 (x + y=4) is active at 40°C in copolymerization of ethylene with propylene over a broad range of monomer concentrations. 2. The molecular weight distribution and structural composition of the products depends on the ratio γo=[C3H6]/[C2H4]o. The maximum yield of C5 olefins is 45% with γo=7–32. 3. Under conditions of codimerization, ethylene accelerates the dimerization of propylene quite substantially.