The Experts below are selected from a list of 4689 Experts worldwide ranked by ideXlab platform
M R Rahimpour - One of the best experts on this subject based on the ideXlab platform.
-
characterization and catalytic properties of molybdenum supported on nano gamma al2o3 for upgrading of Anisole model compound
Chemical Engineering Journal, 2017Co-Authors: Majid Saidi, M R Rahimpour, Behnam RahzaniAbstract:Abstract The conversion of Anisole, a prototypical compound representative of lignin-derived bio-oil, was catalyzed by molybdenum supported on nano gamma alumina catalyst in a flow reactor at 623–723 K, 8 bar pressure and space velocity of 6 (g of Anisole)/(g of catalyst × h). Mo supported nano gamma Al2O3 is synthesized by impregnation method and its physicochemical properties are characterized by XRD, FESEM, EDS and BET techniques. For investigation and evaluation of the support effect, regular gamma support is used for synthesis a catalyst at optimum loading in order to compare the performance of nano gamma alumina supported catalyst. Catalytic upgrading of Anisole over Mo supported nano gamma Al2O3 represented that this type of catalyst is active to form benzene by hydrodeoxygenation (HDO) reaction, phenol by hydrogenolysis, 2-methylphenol by transalkylation, to 2,6-dimethylphenol and 2,3,5,6-tetramethylphenol by alkylation. Experimental analysis revealed that increasing the Mo loading to 20% enhances the Anisole conversion, however high metal loadings leads to metal particles agglomeration and as a result, the surface area will decrease. Also increasing temperature enhances conversion of Anisole. Catalytic investigations indicated that nano gamma alumina supported catalyst exhibited higher catalytic activity than regular gamma alumina supported catalyst.
-
catalytic hydrodeoxygenation of Anisole over nickel supported on plasma treated alumina silica mixed oxides
RSC Advances, 2017Co-Authors: Hamed Taghvaei, M R Rahimpour, Peter BruggemanAbstract:Hydrodeoxygenation (HDO) of Anisole, a representative of lignin-derived bio oil, was investigated on SiO2–Al2O3 supported Ni nano-particles at low hydrogen pressure. Plasma was used for the surface modification of the support. The supports and catalysts were characterized by N2 physisorption, FT-IR spectroscopy, Temperature Program Desorption of ammonia (NH3-TPD), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results showed that the plasma treatment improved both the SiO2–Al2O3 surface characteristics and pore structure. The catalyst with a plasma treated support had a higher dispersion and smaller NiO particle size, leading to an improved hydrodeoxygenation activity and product selectivity. Phenol and benzene were the major products of Anisole HDO. Demethylation, hydrodeoxygenation and transalkylation reactions are the main chemical reactions for Anisole upgrading using the Ni/Al2O3–SiO2 catalyst. Compared to the untreated catalyst, the plasma treated Ni/Al2O3–SiO2 catalyst gives higher Anisole conversion at atmospheric pressure by which valuable products were obtained with higher selectivity.
-
experimental investigation of upgrading of lignin derived bio oil component Anisole catalyzed by carbon nanotube supported molybdenum
RSC Advances, 2017Co-Authors: Behnam Rahzani, Majid Saidi, Hamid Reza Rahimpour, Bruce C. Gates, M R RahimpourAbstract:Molybdenum supported on carbon nanotubes (CNTs) was synthesized and evaluated as a catalyst for the catalytic hydroprocessing of Anisole. The CNTs and supported catalysts were characterized by X-ray diffraction crystallography, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and surface area/pore volume measurements. The Anisole conversion products and selectivity-conversion data led to the identification of kinetically significant reaction routes, hydrodeoxygenation (HDO) and hydrogenolysis, accompanied by some alkylation, and transalkylation; for example, including Anisole conversion to benzene by HDO and to phenol by hydrogenolysis, and formation of methyl-substituted phenols by transalkylation and alkylation. The activity and selectivity of the CNT-supported catalyst compare favorably with those of comparable catalysts on other supports, but the molybdenum in the carbon nanotubes limits the access of reactants to the catalytically active molybdenum species.
-
experimental investigation on upgrading of lignin derived bio oils kinetic analysis of Anisole conversion on sulfided como al2o3 catalyst
International Journal of Chemical Kinetics, 2016Co-Authors: Hamid Reza Rahimpour, Majid Saidi, Parisa Rostami, Bruce C. Gates, M R RahimpourAbstract:Kinetics of the hydroprocessing of Anisole, a compound representative of lignin-derived bio-oils, catalyzed by a commercial sulfided CoMo/Al2O3, was determined at 8–20 bar pressure and 573–673 K with a once-through flow reactor. The catalyst was sulfided in an atmosphere of H2 + H2S prior to the measurement of its performance. Selectivity-conversion data were used as a basis for determining an approximate, partially quantified reaction network showing that hydrodeoxygenation (HDO), hydrogenolysis, and alkylation reactions take place simultaneously. The data indicate that these reactions can be stopped at the point where HDO is virtually completed and hydrogenation reactions (and thus H2 consumption) are minimized. Phenol was the major product of the reactions, with direct deoxygenation of Anisole to give benzene being kinetically almost insignificant under our conditions. We infer that the scission of the Cmethyl–O bond is more facile than the scission of the Caromatic–O bond, so that the HDO of Anisole likely proceeds substantially through the reactive intermediate phenol to give transalkylation products such as 2-methylphenol. The data determine rates of formation of the major primary products. The data show that if oxygen removal is the main processing goal, higher temperatures and lower pressures are favored.
-
kinetics of upgrading of Anisole with hydrogen catalyzed by platinum supported on alumina
Energy & Fuels, 2015Co-Authors: Majid Saidi, Parisa Rostami, Hamid Reza Rahimpour, Mohammad Ali Roshanfekr Fallah, Bruce C. Gates, M R Rahimpour, Sona RaeissiAbstract:Kinetics of the reactions of Anisole, a model compound representative of lignin-derived bio-oils, with H2, catalyzed by Pt/Al2O3, were investigated with a fixed-bed tubular microflow reactor at 573–673 K, 8–14 bar, and space velocities in the range of 3–240 (g of Anisole)/(g of catalyst × h). Selectivity–conversion data were used as a basis to propose an approximate reaction network and estimate parameters in approximate rate equations. The reactions include the following: Anisole conversion to phenol by hydrogenolysis, to 2-methylphenol by transalkylation, to 2,4-dimethylphenol, 2,4,6-trimethylphenol, and 2,3,5,6-tetramethylphenol by transalkylation and alkylation, to benzene by hydrodeoxygenation (HDO), and to hexamethylbenzene by HDO and alkylation. The primary reactions are satisfactorily represented with the approximation that each is first-order in the organic reactant. The apparent activation energy for the hydrogenolysis reaction that leads to phenol formation is approximately 25.3 kJ/mol, and the...
Hamed Taghvaei - One of the best experts on this subject based on the ideXlab platform.
-
catalytic hydrodeoxygenation of Anisole over nickel supported on plasma treated alumina silica mixed oxides
RSC Advances, 2017Co-Authors: Hamed Taghvaei, M R Rahimpour, Peter BruggemanAbstract:Hydrodeoxygenation (HDO) of Anisole, a representative of lignin-derived bio oil, was investigated on SiO2–Al2O3 supported Ni nano-particles at low hydrogen pressure. Plasma was used for the surface modification of the support. The supports and catalysts were characterized by N2 physisorption, FT-IR spectroscopy, Temperature Program Desorption of ammonia (NH3-TPD), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results showed that the plasma treatment improved both the SiO2–Al2O3 surface characteristics and pore structure. The catalyst with a plasma treated support had a higher dispersion and smaller NiO particle size, leading to an improved hydrodeoxygenation activity and product selectivity. Phenol and benzene were the major products of Anisole HDO. Demethylation, hydrodeoxygenation and transalkylation reactions are the main chemical reactions for Anisole upgrading using the Ni/Al2O3–SiO2 catalyst. Compared to the untreated catalyst, the plasma treated Ni/Al2O3–SiO2 catalyst gives higher Anisole conversion at atmospheric pressure by which valuable products were obtained with higher selectivity.
-
upgrading of Anisole in a dielectric barrier discharge plasma reactor
Energy & Fuels, 2014Co-Authors: Hamed Taghvaei, Parisa Rostami, Bruce C. Gates, Mahsa Kheirollahivash, Mohammad Ghasemi, M R RahimpourAbstract:A dielectric barrier discharge (DBD) plasma reactor for upgrading of Anisole, a model compound representative of lignin-derived bio-oils, was investigated with helium as a carrier gas. The effects of carrier gas flow rate, liquid Anisole feed flow rate, and reactor length on the reactor performance were investigated. As a result of the decomposition of Anisole, the most prevalent free radical species that formed is inferred to have been phenoxy, resulting from the breaking of the Cmethyl–O bond. The residence times of reactive species and feed molecules are inferred to be key parameters affecting the conversion of Anisole as well as the distribution of products. The three main classes of reaction of Anisole were demethylation to give phenol, transalkylation, yielding 4-methylAnisole and methylphenols, and hydrogenolysis of phenol to give benzene. The optimal experimental conditions were the carrier gas flow rate of 100 mL/min, the feed flow rate of 0.1 mL/min, and the outer electrode length of 20 cm; the ...
-
noncatalytic upgrading of Anisole in an atmospheric dbd plasma reactor effect of carrier gas type voltage and frequency
Energy & Fuels, 2014Co-Authors: Hamed Taghvaei, Parisa Rostami, Mahsa Kheirollahivash, Mohammad Ghasemi, M R RahimpourAbstract:In this article, an atmospheric dielectric barrier discharge (DBD) plasma reactor was used as a novel tool for the upgrading of bio-oil using Anisole as a model compound. The influences of different carrier gases (Ar, H2, and He) on the performance of the reactor were carefully studied. The results revealed that the conversion of Anisole in He plasma is higher than that in Ar or H2 plasma. This may be attributed to the more stable and homogeneous discharge of He plasma. It is believed that in all of the experiments phenoxy radical was formed as the primary product of Anisole dissociation via electron-attack reactions. Moreover, the most abundant product was phenol, which was formed by the free-radical reaction between phenoxy and H radicals. It was found that the upgrading of Anisole involved demethylation, transalkylation, and hydrogenolysis reactions. In addition to phenol, 4-methylAnisole, 2-methylphenol, benzene, 4-methylphenol, 2,6-dimethylAnisole, and cyclohexane were also formed in the reactor. Fur...
Changhai Liang - One of the best experts on this subject based on the ideXlab platform.
-
NiMoAl catalysts derived from heptamolybdate-intercalated layered double hydroxides for hydrodeoxygenation of Anisole
BMC Chemical Engineering, 2019Co-Authors: Xingzhao Zhang, Xiao Chen, Zhijian Peng, Chi-wing Tsang, Changhai LiangAbstract:The catalytic performance of NiMoAl catalysts derived from layered double hydroxide (LDH) precursors with molybdenum species incorporated into the interlayers was investigated for the hydrodeoxygenation (HDO) of Anisole as a model compound of the lignin. The results showed that high dispersion of small Ni nanoparticles with 2–5 nm due to the pinning effect of Mo from Mo7O246− intercalated the LDHs. Due to presence of the oxygen vacancy sites on the molybdenum oxide, the NiMoAl catalysts exhibit higher conversion of Anisole than the corresponding NiAl catalyst. The activity for hydrodeoxygenation was enhanced with the increased content of molybdenum species, which can be attributed to the larger amount of acid sites-promoted removal of oxygen from Anisole. In addition, the NiMoAl catalysts show higher resistance to deactivation than the NiAl catalyst, and can be broadly applied to other hydrodeoxygenation reactions.
-
ni al2o3 catalysts derived from layered double hydroxide and their applications in hydrodeoxygenation of Anisole
ChemistrySelect, 2016Co-Authors: Shaohua Jin, Xiao Chen, Xingzhao Zhang, Zhijian Peng, Changhai LiangAbstract:The catalytic performance of Ni/Al2O3 catalysts derived from layered double hydroxide precursors with nickel ions incorporated into the brucite-like layers was investigated for the hydrodeoxygenation (HDO) of Anisole as a model compound of the lignin. Upon calcination and subsequent reduction, the well-crystallized phase and highly dispersed Ni nanoparticles (3∼10 nm) on the support were obtained. The catalysts exhibited high activity toward the hydrogenolysis of C−O bonds and the hydrogenation saturation of aromatic ring at low temperature (200-280 °C) and appropriate hydrogen pressure (2 MPa). The activity and selectivity of these two main reaction pathways of Anisole conversion were independent of the Ni content. And the direct cleavage of Caromatic-O bond of Anisole forming benzene as another parallel pathway prevails at increasing temperature. In addition, the catalysts are highly resistant to coking and easy to be reactivated by the utilization of the layered double hydroxide precursors.
-
catalytic hydrodeoxygenation of Anisole as lignin model compound over supported nickel catalysts
Catalysis Today, 2014Co-Authors: Shaohua Jin, Zihui Xiao, Xiao Chen, Lei Wang, Jiacheng Xing, Changhai LiangAbstract:Abstract Catalytic hydrodeoxygenation (HDO) of Anisole, a methoxy-rich lignin model compound, has been investigated over a series of Ni-containing (10 wt% loading) catalysts with activated carbon, SBA-15, SiO2, and γ-Al2O3 supports, in order to understand their ability for removal of OCH3 from Anisole. This catalytic reaction had been carried out in an autoclave at 180–220 °C and 0.5–3.0 MPa H2 pressure. Nickel-catalyzed aromatic ring-hydrogenation compared with the subsequent demethylation and deoxygenation is the fastest step in HDO of Anisole under the present reaction conditions. Among these catalysts, the aromatic ring-saturated cyclohexyl methyl ether is mainly obtained over Ni/AC, while the Ni/SiO2 displayed the highest activity in HDO of Anisole (selectivity to deoxygenated products >95%). Differences in HDO efficiency among the catalysts are attributed not only to variations in the dispersion of the active phase, but also to the acid sites which may contribute to the cleavage of C O bonds. It has also been shown that the activity toward oxygen-removal strongly depended on reaction temperature and the conversion of Anisole favors the production of oxygen-free aromatics by the direct demethoxylation pathway at the relatively low H2 pressure.
Aditya Bhan - One of the best experts on this subject based on the ideXlab platform.
-
chemical titration and transient kinetic studies of site requirements in mo2c catalyzed vapor phase Anisole hydrodeoxygenation
ACS Catalysis, 2015Co-Authors: Wensheng Lee, Zhenshu Wang, Anurag Kumar, Aditya BhanAbstract:The turnover frequency (TOF) of benzene synthesis from vapor phase Anisole hydrodeoxygenation (HDO), estimated via in situ CO titration, was found to be invariant (1.1 ± 0.3 × 10–3 s–1) over molybdenum carbide (Mo2C) catalysts with varying CO chemisorption uptakes (∼70 to ∼260 μmol g–1, measured ex situ at 323 K). Accumulation of oxygen (∼0.29 monolayer) over Mo2C catalysts was determined by an oxygen mass balance during the transient of Anisole HDO at 423 K under ambient pressure (H2/Anisole molar ratio ∼ 110). Similar product selectivity, apparent activation energy, and TOF of benzene synthesis for an oxygen treated (with oxygen incorporation: O/Mobulk (molar ratio) = 0.075) and freshly prepared Mo2C catalysts (no exposure to air prior to kinetic measurements) demonstrate that the effect of oxygen at these low concentrations is solely to reduce the number of active sites for Anisole HDO, resulting in a lower (∼3 times) benzene synthesis rate per gram of catalyst for the oxygen-modified material. The obs...
-
selective vapor phase hydrodeoxygenation of Anisole to benzene on molybdenum carbide catalysts
Journal of Catalysis, 2014Co-Authors: Zhenshu Wang, Ryan J Wu, Aditya BhanAbstract:Abstract Vapor-phase hydrodeoxygenation (HDO) of Anisole over Mo 2 C catalysts at low temperatures (420–520 K) and ambient pressure showed (1) remarkable selectivity for C–O bond cleavage, giving benzene selectivity >90% among C 6 + products, (2) high hydrogen efficiency for the HDO reaction as indicated by low cyclohexane selectivity ( 2 /Anisole pressure, and the preferential inhibition of benzene synthesis rates upon introduction of CO relative to isotopic HD exchange suggest that catalytic sites for H 2 activation are distinct from those required for the activation of Anisole. The involvement of metallic sites on Mo 2 C catalysts for this reaction was demonstrated by the nearly invariant benzene synthesis rate per CO chemisorption site.
Zhenshu Wang - One of the best experts on this subject based on the ideXlab platform.
-
encapsulation of molybdenum carbide nanoclusters inside zeolite micropores enables synergistic bifunctional catalysis for Anisole hydrodeoxygenation
ACS Catalysis, 2017Co-Authors: Zhenshu Wang, Manish Shetty, Takayuki Iida, Karthick Murugappan, Koji Ohara, Toru Wakihara, Yuriy RomanleshkovAbstract:Molybdenum carbide (MoCx) nanoclusters were encapsulated inside the micropores of aluminosilicate FAU zeolites to generate highly active and selective bifunctional catalyst for the hydrodeoxygenation of Anisole. Interatomic correlations obtained with differential pair distribution function analysis confirmed the intraparticle structure and the uniform size of the MoCx nanoclusters. The reactivity data showed the preferential production of alkylated aromatics (such as toluene and xylene) over benzene during the hydrodeoxygenation of Anisole as well as the minimization of unwanted CH4 formation. Control experiments demonstrated the importance of MoCx encapsulation to generate an efficient bifunctional catalyst with superior carbon utilization and on-stream stability.
-
chemical titration and transient kinetic studies of site requirements in mo2c catalyzed vapor phase Anisole hydrodeoxygenation
ACS Catalysis, 2015Co-Authors: Wensheng Lee, Zhenshu Wang, Anurag Kumar, Aditya BhanAbstract:The turnover frequency (TOF) of benzene synthesis from vapor phase Anisole hydrodeoxygenation (HDO), estimated via in situ CO titration, was found to be invariant (1.1 ± 0.3 × 10–3 s–1) over molybdenum carbide (Mo2C) catalysts with varying CO chemisorption uptakes (∼70 to ∼260 μmol g–1, measured ex situ at 323 K). Accumulation of oxygen (∼0.29 monolayer) over Mo2C catalysts was determined by an oxygen mass balance during the transient of Anisole HDO at 423 K under ambient pressure (H2/Anisole molar ratio ∼ 110). Similar product selectivity, apparent activation energy, and TOF of benzene synthesis for an oxygen treated (with oxygen incorporation: O/Mobulk (molar ratio) = 0.075) and freshly prepared Mo2C catalysts (no exposure to air prior to kinetic measurements) demonstrate that the effect of oxygen at these low concentrations is solely to reduce the number of active sites for Anisole HDO, resulting in a lower (∼3 times) benzene synthesis rate per gram of catalyst for the oxygen-modified material. The obs...
-
selective vapor phase hydrodeoxygenation of Anisole to benzene on molybdenum carbide catalysts
Journal of Catalysis, 2014Co-Authors: Zhenshu Wang, Ryan J Wu, Aditya BhanAbstract:Abstract Vapor-phase hydrodeoxygenation (HDO) of Anisole over Mo 2 C catalysts at low temperatures (420–520 K) and ambient pressure showed (1) remarkable selectivity for C–O bond cleavage, giving benzene selectivity >90% among C 6 + products, (2) high hydrogen efficiency for the HDO reaction as indicated by low cyclohexane selectivity ( 2 /Anisole pressure, and the preferential inhibition of benzene synthesis rates upon introduction of CO relative to isotopic HD exchange suggest that catalytic sites for H 2 activation are distinct from those required for the activation of Anisole. The involvement of metallic sites on Mo 2 C catalysts for this reaction was demonstrated by the nearly invariant benzene synthesis rate per CO chemisorption site.