Hydrogenation Of 1-octene Research Articles

CoMo/Al<sub>2</sub>O<sub>3</sub>触媒の1-オクテン水素化活性および表面構造に及ぼす<i>trans</i>-1,2-シクロヘキサンジアミン-<i>N</i>,<i>N</i>,<i>N</i> ',<i>N</i> '-四酢酸の添加効果

The present study investigated the effects of trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CyDTA) addition on the 1-octene hydrogenation activity and surface structure of CoMo/Al 2 O 3 catalyst as a method to control the olefin hydrogenation activity. Irrespective of Co/Mo molar ratio, 1-octene hydrogenation activity at 453 K and 1.3 MPa decreased in the following order: Mo/Al 2 O 3 > CoMo/Al 2 O 3 > CyDTA-CoMo/Al 2 O 3 Co/Al 2 O 3 . Modification with CyDTA had little effect on the hydrogenation activity of Mo/Al 2 O 3 . Thus, modification with CyDTA facilitates the inhibiting effect of Co addition on the hydrogenation of 1-octene. Our previous study found that modification with CyDTA greatly improves the hydrodesulfurization (HDS) activity of CoMo/Al 2 O 3 . Therefore, we expect that modification with CyDTA will greatly improves the HDS selectivity of CoMo/Al 2 O 3 in the presence of olefins. Furthermore, the present characterization of CoMo/Al 2 O 3 modified with CyDTA by NO adsorption techniques suggested that modification of CoMo/Al 2 O 3 with CyDTA facilitates the formation of the Co-Mo-S phase even at lower Co/Mo molar ratio, at which Co atoms block the edge sites of MoS 2 nanoclusters, leading to the improved HDS selectivity.

Oscillation theory: Part 3. Enhancement of a commercial catalyst by pore modification

In previous papers [L.B. Datsevich, Appl. Catal. A 250 (2003) 125–141; L.B. Datsevich, Catal. Today 79–80 (2003) 341–348; L.B. Datsevich, Appl. Catal. A 247/1 (2003) 101–111] devoted to the oscillatory motion of liquid in catalyst pores in gas–liquid reactions with gas and/or heat production, some directions of catalyst and process development have been discussed. It has been supposed that modification of the pore structure of catalysts can provoke oscillations in pores, leading to an acceleration of internal mass transfer and to an increase in the overall reaction rate. The present paper deals with a confirmation of this theoretical conclusion. It shows that an unsophisticated change in the pore structure can intensify the process of 1-octene hydrogenation to n-octane on a Ni tablet catalyst up to three times.

Effects of Co Addition on the Surface Structure and the Activity of Mo/Al<sub>2</sub>O<sub>3</sub> Catalyst for the Hydrogenation of Olefins

The present study investigated the effects of Co addition on the surface structure and activity of Mo/Al 2 O 3 for the hydrogenation of C 6 -C 10 olefins. CoMo/Al 2 O 3 (Co/Mo atomic ratio: 0.56) had lower activity for the hydrogenation of 1-hexene, 1-octene and 1-decene than Mo/Al 2 O 3 , whereas CoMo/Al 2 O 3 had higher activity for the hydrogenation of 2-octene, 2,4,4-trimethyl-2-pentene and cyclohexene. Co/Al 2 O 3 showed no activity for the hydrogenation of 1-octene and 2,4,4-trimethyl-2-pentene. NO uptake measurements over Mo/Al 2 O 3 suggested that the coordinatively unsaturated sites of Mo atoms located at the edges of MoS 2 clusters were active for the hydrogenation of both 1-octene and 2,4,4-trimethyl-2-pentene. Diffuse reflectance FTIR measurements of NO adsorbed on CoMo/Al 2 O 3 (Co/Mo atomic ratio: 0.56) indicated that Co atoms blocked Mo atoms located at the edges of MoS 2 clusters almost completely, i.e. formation of the Co-Mo-S structure. Therefore, formation of the Co-Mo-S structure depressed the activity for hydrogenation of 1-octene. The addition of Co promoter also increased the stacking number of MoS 2 clusters. Presumably the increase in the stacking number of MoS 2 clusters facilitated the adsorption of bulky olefins and promoted the hydrogenation. This may be the main reason for the promoting effect of Co for the hydrogenation of 2,4,4-trimethyl-2-pentene.

Characterization of the Ni-Zn/TiO<SUB>2</SUB> Nanocomposite Synthesized by the Liquid-Phase Selective-Deposition Method

The characterization of Ni-Zn/TiO 2 nanocomposite synthesized by the liquid-phase selective-deposition method was studied. Nanoparticles were well dispersed and stabilized by the selective deposition onto TiO 2 surface. The particle size was decreased with increasing the amount of Zn added, thus the catalytically active Ni surface area was increased. The selective deposition onto TiO 2 surface and addition of Zn to the nanoparticles promoted the catalytic activity of Ni-Zn nanoparticles, e.g. the catalytic activity of Ni-Zn/TiO 2 for 1-octene hydrogenation was ca. 10 times higher than that of the unsupported Ni nanoparticles. Ni in the nanocomposite was assigned as metallic, although their surface was oxidized under the atmospheric condition, but Zn and B were deposited as their oxide.

Kinetics of the Homogeneous Catalytic Hydrogenation of Olefins in Supercritical Carbon Dioxide Using a Fluoroacrylate Copolymer Grafted Rhodium Catalyst

The kinetic studies on the hydrogenation of 1-octene and cyclohexene using a fluoroacrylate copolymer grafted rhodium catalyst in supercritical carbon dioxide (scCO2) are reported. The reactions were investigated at temperatures between 50 and 120 °C, and pressures ranging from 172 to 241 bar. The catalyst also deactivated at these reaction conditions. For the case of 1-octene, isomerization to (E)2-octene and (Z)2-octene also occurred as side reactions. To represent the experimental data, a kinetic model was developed on the basis of reported studies about hydrogenation and isomerization of olefins in conventional solvents. It was proposed that two hydride catalytic species are formed during the kinetic cycle. Monohydride species promoted the isomerization, and dihydride species catalyzed the hydrogenation. Deactivation of the catalyst was attributed to the formation of an unsaturated olefin complex. Statistical methods were applied to discriminate among rival models. It was found that the rate-determini...

Sono synthesis and characterization of nano-phase molybdenum-based materials for catalytic hydrodesulfurization

Unsupported nano-phase MoS 2, CoS, and CoS-MoS 2 (Mo/Co mole ratio ∼6/1) materials were prepared in hexadecane by sonolysis of the corresponding metal carbonyls at ∼50 °C in high (>90%) yields as measured by the evolved carbon monoxide. Direct sonolysis of commercial micron-sized MoS 2 in hexadecane did not result in nano-sizing. The TEM images showed that the synthesized MoS 2 were aggregates of ∼20 nm mean particle diameter, CoS was ∼50 nm and the mixed-metal CoS-MoS 2 could be viewed as a composite in which smaller MoS 2 particles resided on the larger crystallites of CoS. The broad XRD peaks were consistent with nano-structured MoS 2 and the sharp peaks were consistent with a more crystalline CoS-MoS 2 species. The sharp peaks did not fit any single CoS pattern suggesting multiple phases. The XRD data showed that sonolysis did not alter the morphology of the micron-sized commercial MoS 2 sample. In the HDS comparative activity study of dibenzothiophene, the synthesized nano-phase MoS 2 exhibited more than an order of magnitude higher activity than its commercial micron-sized counterpart and the addition of Co further enhanced the activity. The HDS activity mirrored the temperature programmed reduction data. Interestingly, the nano-phase materials were less active for hydrogenation of 1-octene during the HDS study.

A study of synthesis, characterization and catalytic hydrogenation by polymer anchored Pd(II)-amino acid complexes

Abstract l -Valine was anchored to 6% and 8% cross-linked poly(styrene-divinyl benzene) resin and its complex with palladium chloride was prepared. The newly synthesized catalysts were characterized by various techniques such as elemental analysis, FT-IR, DRS, SEM and TGA. Physico-chemical properties like surface area, swelling behavior in different solvents, bulk density, etc. have been determined. The polymer supported Pd complexes behave as versatile and recyclable catalysts for the hydrogenation of 1-octene, cyclohexene, acetophenone and nitrobenzene. Kinetics of hydrogenation of 1-octene has been investigated in detail. The influence of different reaction parameters on conversion and selectivity to products are reported.

Enhanced Hydrogenation Activity and Recycling of Cationic Rhodium Diphosphine Complexes through the Use of Highly Fluorous and Weakly‐Coordinating Tetraphenylborate Anions

AbstractThe effect of the nature of the anion on the performance of ionic rhodium catalysts has received little attention. Herein it is shown that the use of highly fluorous tetraphenylborate anions can enhance catalyst activity in both conventional and fluorous media. For hydrogenation catalysts of the type [Rh(COD)(dppb)][X] {COD=1,5‐cis,cis‐cyclooctadiene; dppb=1,4‐bis(diphenylphosphino)butane; X=BF4− (1a), [BPh4]− (1b), [B{C6H4(SiMe3)‐4}4]− (1c), [B{C6H3(CF3)2‐3,5}4]− (1d), [B{C6H4(SiMe2CH2CH2C6F13)‐4}4]− (1e), [B{C6H4(C6F13)‐4}4]− (1f) and [B{C6H3(C6F13)2‐3,5}4]− (1 g)} the activity towards the hydrogenation of 1‐octene in acetone increased in the order 1c <1b <1e <1a <1d ~ 1f <1g with 1g being twice as active as the commonly applied 1a. Despite the fluorophilic character introduced by the substituted tetraarylborate anions, the presence of some perfluoroalkyl‐substituents in the cation was still required for achieving high partition coefficients. Therefore, [Rh(COD)(Ar2PCH2CH2PAr2)][X] {Ar=C6H4(SiMe2CH2CH2C6F13)‐4, X=[B{C6H3(C6F13)2‐3,5}4]− (3f); Ar=C6H4(SiMe(CH2CH2C6F13)2)‐4 and X=[B{C6H4(C6F13)‐4}4]− (2g)} were prepared, which were active in the hydrogenation of 1‐octene, 2g even more so than 3f. Both these highly fluorous catalysts could be recycled with 99% efficiency through fluorous biphasic separation, whereas the corresponding BF4− complex of 2g (2a) did not show any affinity for the fluorous phase.

Reductive Deposition of Ni-Zn Nanoparticles Selectively on TiO<SUB>2</SUB> Fine Particles in the Liquid Phase

A novel metal nanoparticle synthesis method has been developed, in which metallic Ni nanoparticles with an amorphous-like structure were selectively deposited on TiO2 fine particles through the reduction from the liquid phase. The addition of Zn proved to decrease the nanoparticles size, leading to the increase in the total area of catalytically active Ni surface. In addition, nanoparticles were highly stabilized by the deposition on TiO2, so that the catalytic activity of Zn-added TiO2-supported Ni nanoparticles (Ni-Zn/TiO2) in the 1-octene hydrogenation was ca. 10 times higher than that of unsupported Ni nanoparticles.

Catalytic hydrogenation by recyclable supported Pd(II)-amino acid complex

L-phenyl alanine was anchored to P(S-DVB) resin and its complex with PdCl2 was prepared. The newly synthesized catalyst was found to be a versatile and recyclable catalyst for the hydrogenation of 1-octene and acetophenone. This chiral catalyst induced moderate enantioselectivity during the asymmetric reduction of acetophenone.

Hydrogenation of alkenes over palladium and platinum metals supported on a variety of metal(IV) phosphates

Platinum(0) and palladium(0) catalysts have been prepared by first exchanging the acidic protons in a variety of metal(IV) phosphates with platinum or palladium ions followed by their reduction to metal. The resulting supported catalysts were examined for their effectiveness in the hydrogenation of 1-octene, 1-, 3-, 4-methylcyclohexenes and cyclododecene. Rates of reduction and stereoselectivity were compared with a standard commercial palladium-on-charcoal catalyst and were found to vary widely by a factor of about 500, depending on the support used. Data are reported as relative rates of reduction. Steric effects due to substrate/support interaction played a major role in selectivity to hydrogenation.

Experimental and Theoretical Studies on Hydrogenation in Multiphase Fixed-Bed Reactors

Multiphase fixed-bed reactors have complex hydrodynamic and mass transfer characteristics. The modeling and scale-up are therefore difficult. The present work focuses on the role of mass transfer on the effective reaction rate. The catalytic 1-octene hydrogenation was taken as a model reaction. The reaction rate in the trickle-bed reactor is by a factor of 20 smaller than (theoretically) in the absence of any mass transfer limitations. For high octene concentrations (> 10 %), the effective reaction rate is limited by the H2 consumption, above all by the gas/liquid and liquid/solid mass transfer. For lower octene concentrations the reaction is zero order with respect to H2 and only depends on the octene consumption, i.e., on the interplay of chemical reaction, L/S and intraparticle mass transfer of octene.

Homogeneous hydrogenation of 1-octene: effect of anion, solvent and ligand on hydrogenation activity and selectivity: Crystal structure of the catalyst precursor [Ni( o-MeO-dppp)(tfa) 2

The effect of solvent, anion, and amount of ligand on the catalytic hydrogenation of 1-octene by nickel(II) complexes containing the ligands 1,2-bis(di( ortho-methoxyphenyl)phosphanyl)ethane ( o-MeO-dppe) and 1,3-bis(di( ortho-methoxyphenyl)-phosphanyl)propane ( o-MeO-dppp) is reported. Catalysts containing the ligand o-MeO-dppe are more sensitive towards variations in solvents and anions than the catalysts containing the ligand o-MeO-dppp. The active catalyst precursor complex [Ni( o-MeO-dppp)(tfa) 2] (tfa=trifluoroacetate) was characterized with X-ray crystallography. The complex has a crystallographic C 2 symmetry; the nickel ion is in a square–planar geometry with two phosphorus donors and two tfa oxygen donors in a cis configuration (Ni–P distance 2.1527(4) Å, Ni–O distance 1.9186(10) Å). In reaction mixtures containing o-MeO-dppe ligand redistribution takes place, leading to the formation of an inactive bis(ligand) complex. To prevent the ligand redistribution reaction the bulkier ligand 1,2-bis(di( ortho-ethoxyphenyl)phosphanyl)ethane ( o-EtO-dppe) has been synthesized. Even though NMR analysis showed that its nickel complex also is involved in a ligand-redistribution equilibrium, the hydrogenation activity is considerably higher than that of a catalyst containing the ligand o-MeO-dppe.

Fluorous derivatives of [Rh(COD)(dppe)]BX 4 (X=F, Ph): synthesis, physical studies and application in catalytic hydrogenation of 1-alkenes and 4-alkynes

Fluorous derivatives of 1,2-bis(diphenylphosphino)ethane (dppe) ( 1 ), containing a para-(1 H,1 H,2 H,2 H-perfluoroalkyl)silyl function, were used in the synthesis of fluorous derivatives of [Rh(COD)(dppe)]BF 4. The single crystal X-ray crystallographic structure of [Rh(COD)( 1a )]BPh 4 ( 7 ) was determined ( 1a =[CH 2P(C 6H 4–SiMe 2CH 2CH 2C 6F 13- p) 2] 2). Large differences in catalytic activity and selectivity (higher hydrogenation activity and lower isomerization activity) relative to [Rh(COD)(dppe)]BF 4 were observed in the hydrogenation of 1-octene using non-fluorous, silyl-substituted [Rh(COD)( 2 )]BF 4 ( 5 ; 2 =[CH 2P(C 6H 4–SiMe 3- p) 2] 2 or [Rh(COD)( 3 )]BF 4 ( 6 ; 3 =[CH 2P(C 6H 4–SiMe 2C 8H 17- p) 2] 2) and even more so with fluorous [Rh(COD)( 1a )]BF 4 ( 4a ). For 4a and 6 , the presence of aggregates was demonstrated by dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryoTEM), which is most probably responsible for these differences. Similar differences between (fluorous) silylated catalysts and non-substituted [Rh(COD)(dppe)]BF 4 were observed in the semi-hydrogenation of 4-octyne. Recycling of highly fluorous catalyst [Rh(COD)( 1c )]BF 4 ( 4c ; 1c =[CH 2P(C 6H 4-Si(CH 2CH 2C 6F 13) 3- p) 2] 2) was investigated in two different fluorous biphasic solvent systems. The catalyst could be recycled with 97.5% (for PFMCH/acetone, 1:1 v/v) and >99.92% (for FC-75/hexanes, 1:3 v/v) retention of rhodium, respectively. The leaching of phosphorus was comparable to the leaching of rhodium (in PFMCH/acetone), showing that dissociation and leaching of free ligand does not take place for these rhodium diphosphine catalysts.

Homogeneous catalysis in supercritical carbon dioxide with rhodium catalysts tethering fluoroacrylate polymer ligands

Rhodium(I) complexes for homogeneous catalysis in supercritical carbon dioxide, scCO 2, have been prepared from the reaction of phosphine containing fluoroacrylate polymeric ligands with [Rh(μ-Cl)(COD)] 2. The fluoroacrylate polymer used was prepared via a free radical initiator polymerization reaction from 1 H,1 H,2 H,2 H-heptadecafluorodecyl acrylate monomer and N-acryloxysuccinimide, NASI. Diphenylphosphinopropylamine, DPPA, was attached to the copolymer as it replaces the NASI group, thus providing the copolymer a phosphine ligand for coordination. 31P NMR and UV–Vis spectra were used to confirm the coordination of phosphine in the polymer to Rh(I). The synthesized catalysts possess excellent solubility in scCO 2. Hydrogenation of 1-octene in scCO 2 resulted in conversion (70%) to n-octane within 12 h (reaction conditions 70°C, 172 bar, 1:4000 catalyst/substrate mole ratio).

Kinetics of the hydrogenation of 1-octene catalyzed by [Ni( o-MeO-dppp)(OAc) 2

The kinetics of the nickel-catalyzed hydrogenation of 1-octene have been studied using nickel(II) acetate in combination with the ligand 1,3-bis(di( o-methoxyphenyl)phosphanyl)propane ( o-MeO-dppp). The effects of temperature and dihydrogen pressure, as well as the influence of the nickel and substrate concentrations have been studied ( T=30–60°C, p(H 2)=30–60 bar, [Ni]=0.35–2.81 mM, [1-octene]=0.98–3.91 M, ligand/Ni=1.1 in a mixture of dichloromethane and methanol). The kinetic study results in the surprisingly simple rate law r= k cat[Ni][1-octene] p(H 2). The kinetic data are consistent with a mechanism in which the terminating hydrogenolysis step of the nickel–alkyl complex is the rate-determining step of the catalytic cycle with all preceding steps at equilibrium. The first-order dependence on the substrate is confirmed by the results with other substrates, as the hydrogenation rate strongly depends on the nature of the substrate.

A silica-supported, switchable, and recyclable hydroformylation-hydrogenation catalyst.

A homogeneous hydroformylation catalyst, designed to produce selectively linear aldehydes, was covalently tethered to a polysilicate support. The immobilized transition-metal complex [Rh(A)CO]+(1+)), in which A is N-(3-trimethoxysilane-n-propyl)-4,5-bis(diphenylphosphino)phenoxazine, was prepared both via the sol-gel process and by covalent anchoring to silica. 1+ was characterized by means of (31)P and (29)Si MAS NMR, FT-IR, and X-ray photoelectron spectroscopy. Polysilicate immobilized Rh(A) performed as a selective hydroformylation catalyst showing an overall selectivity for the linear aldehyde of 94.6% (linear to branched aldehyde ratio of 65). In addition 1-nonanol, obtained via the hydrogenation of the corresponding aldehyde, was formed as an unexpected secondary product (3.6% at 20% conversion). Under standard hydroformylation conditions, 1+ and HRh(A)(CO)(2)(1) coexist on the support. This dual catalyst system performed as a hydroformylation/hydrogenation sequence catalyst (Z), giving selectively 1-nonanol from 1-octene; ultimately, 98% of 1-octene was converted to mainly 1-nonanal and 97% of the nonanal was hydrogenated to 1-nonanol. The addition of 1-propanol completely changes Z in a hydroformylation catalyst (X), which produces 1-nonanal with an overall selectivity of 93%, and completely suppresses the reduction reaction. If the atmosphere is changed from CO/H(2) to H(2) the catalyst system is switched to the hydrogenation mode (Y), which shows a clean and complete hydrogenation of 1-octene and 1-nonanal within 24 h. The immobilized catalyst can be recycled and the system can be switched reversibly between the three "catalyst modes" X, Y, and Z, completely retaining the catalyst performance in each mode.

Experimental and Theoretical Studies on Hydrogenation in Multiphase Fixed Bed Reactors

Multiphase fixed-bed reactors have complex hydrodynamic and mass transfer characteristics. The modeling and scale-up are therefore difficult. The present work focuses on the role of mass transfer on the effective reaction rate. The catalytic 1-octene hydrogenation was taken as a model reaction. The reaction rate in the trickle-bed reactor is by a factor of 20 smaller than (theoretically) in the absence of any mass transfer limitations. For high octene concentrations (>10%), the effective reaction rate is limited by the H 2 consumption, above all by the gas/liquid and liquid/solid mass transfer. For lower octene concentrations the reaction is zero order with respect to H 2 and only depends on the octene consumption, i.e., on the interplay of chemical reaction, L/S and intraparticle mass transfer of octene.

Hydrogenation reactions on heterogenized Wilkinson complexes

A novel clay catalyst containing a heterogenized Rh(I) triphenylphosphine complex (Rh-bentonite) has been prepared via ion exchange of a Hungarian Na +-bentonite with Wilkinson complex [RhCl(PPh 3) 3]. It was established that the active species [Rh(PPh 3)] + was situated on the external surface of the catalyst, which was found to be efficient in the liquid-phase hydrogenation of 1-octene, cyclohexene, norbornadiene, 1,5-cyclooctadiene, phenylacetylene and cyclohexene-3-one.

Hydrogen Desorption from LaNi5 Hydrides Stabilized with SO2 and CO

The stabilization of the LaNi5H6 hydride was performed by poisoning the surface with CO or SO2, in gaseous or liquid phase. The enhancement of the retention time of hydrogen in the hydride was confirmed for the SO2 treatment, if employed in a liquid phase, compared to the performance of the CO surface treatment. The dehydrogenation kinetics of the untreated, CO-treated, and liquid SO2-treated samples were investigated at 373 K, by the closed-system technique. We found that the dehydrogenation was complete within 120 s for the untreated sample, whereas it took more than 21.6 ks for the liquid SO2 treated LaNi5. The hydrogenation of organic compound (1-octene) using treated LaNi5 hydrides as catalysts was investigated in order to study whether the hydrogen was available or not after the treatments with poison. The hydrogenation of 1-octene was not successfully carried out with the liquid SO2-stabilized hydride, whereas it proceeded well with the gaseous SO2-treated hydride and the gaseous CO-treated one. Th...