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108-88-3Relevant articles and documents
[B(C6F5)4]: An air stable, lewis acidic stibonium salt that activates strong element-fluorine bonds
Pan, Baofei,Gabba?, Fran?ois P.
, p. 9564 - 9567 (2014)
As part of our ongoing interest in main group Lewis acids for fluoride anion complexation and element-fluorine bond activation, we have synthesized the stibonium borate salt [Sb(C6F5)4][B(C 6F5)4] (3). The perfluorinated stibonium cation [Sb(C6F5)4]+ present in this salt is a potent Lewis acid which abstracts a fluoride anion from [SbF 6]- and [BF(C6F5)3] - indicating that it is a stronger Lewis acid than SbF5 and B(C6F5)3. The unusual Lewis acidic properties of 3 are further reflected by its ability to polymerize THF or to promote the hydrodefluorination of fluoroalkanes in the presence of Et 3SiH. While highly reactive in solution, 3 is a perfectly air stable salt, making it a convenient Lewis acidic reagent.
UEBER DIE AUSWIRKUNG VON METHYLSUBSTITUENTEN AUF DIE THERMISCHE ISOMERISIERUNG VON 1,7-OCTADIEN-3-INEN
Kirsch, Reinhard,Priebe, Hanno,Hopf, Henning
, p. 53 - 56 (1984)
The influence of methyl substituents on the 1,7-octadien-3-yne to methylene-vinylcyclopentene rearrangement has been investigated.Whereas methyl groups in the 6-position induce the formation of 1,4-cycloheptadienes, methyl substituents in the 1-position lead to aromatic compounds.
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Hansford,Myers,Sachanen
, p. 671,673 (1945)
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Studies on organolanthanide complexes XXIII. Reaction of organic halides with tricyclopentadienyllanthanides/sodium hydride
Qian, Changtao,Zhu, Dunming,Gu, Yongjie
, p. 23 - 29 (1991)
The reductive dehalogenation of aryl and vinyl halides with tricyclopentadienyllanthanide/sodium hydride systems affords, respectively, the corresponding aromatics and alkenes in excellent yields under mild conditions.However, the reaction with alkyl halides generates alkylated products, which yield alkyl cyclopentadienes after hydrolysis.The reaction mechanism has been briefly investigated.
STUDY OF THE PROPERTIES OF PENTASIL-CONTAINING CATALYSTS IN REACTIONS OF TRANSFORMATION OF HYDROCARBONS. 3. KINETICS OF AROMATIZATION OF PROPANE AND PROPYLENE ON H AND Zn FORMS OF PENTASILS
Sitnik, V. P.,Nekrasov, N. V.,Vasina, T. V.,Yakerson, V. I.,Bragin, O. V.
, p. 641 - 646 (1990)
The kinetics of transformations of propane and propylene on pentasils modified with zinc, Zn/HTsVM, and the H form of zeolite were investigated.Quantitative data were obtained which revealed significant differences for HTsVM and Zn-containing catalysts in the selectivity of transformations of propane with different degrees of its conversion.The promoting effect of Zn in the Zn/HTsVM system not only on the stage of dehydrogenation of propane into propylene, but also on subsequent transformations of propylene into aromatic hydrocarbons, was demonstrated.The absence of internal diffusion inhibition of the reaction in the conditions studied was demonstrated experimentally.It was shown that aromatization of propane takes place in the kinetic region.
Hydrodeoxygenation of m-cresol with Pt supported over mild acid materials
Zanuttini,Dalla Costa,Querini,Peralta
, p. 352 - 361 (2014)
The deoxygenation of m-cresol was studied using Pt catalysts supported on different materials of various levels of acidity, such as gamma alumina, silica, and H-BEA zeolites. The reaction was carried out at atmospheric pressure and 300 °C in a fixed-bed reactor. The catalysts were characterized by XRD, BET, TPR, TEM, H2 and CO chemisorptions, pyridine-TPD and pyridine-IR. The (metal function/acid function) ratio and the reaction conditions were adjusted in order to have a high selectivity to toluene. The effects of acid sites density, strength and type, as well as the pore structure of the different supports on the deoxygenation activity, selectivity and stability were addressed. In order to avoid the production of heavy products and a fast deactivation, the concentration of Br?nsted acid sites must be very low. A high acid sites density is detrimental for catalyst stability, due to coke formation via condensation of precursors adsorbed on adjacent sites. Additionally, a mesoporous structure is better than a microporous structure regarding the stability. All the catalysts can be regenerated in air at relatively low temperature.
Synthesis and functionalization of ordered mesoporous carbons supported Pt nanoparticles for hydroconversion of n-heptane
Said
, p. 14517 - 14529 (2018)
A comprehensive study was performed on the spectroscopic and textural properties of ordered mesoporous carbon (OMC) of the CMK-3 type modified by acid oxidation using K2S2O8 as a benign oxidant and nitrogen-doping by the aid of the polymerization of ethylenediamine and carbon tetrachloride inside the pore channels of SBA-15 hard template. The pristine, nitrogen-doped, and oxidized-ordered mesoporous carbons were used as supports to prepare 10 wt% platinum nanoparticles-loaded catalysts using ethylene glycol as a reducing agent. The catalytic behavior, mechanism, and influence of the surface functionalization of the ordered mesoporous carbon bifunctional catalysts toward the hydroconversion of n-heptane using a fixed-bed flow system operated under atmospheric pressure were investigated. The synthesized samples were characterized by various analytical and spectroscopic techniques. The mesostructural regularity corresponding to the hexagonal P6mm symmetry of the OMC-CMK-3 type was well-reserved even after surface modifications replicated from an SBA-15 template. H2 pulse chemisorption and EDX mapping images confirmed differences in the Pt NPs contents and dispersion depending on the support composition. The catalytic activity results achieved were hand in hand with the proper balance between the acidity strength and Pt NPs dispersion degree.
Mechanism of the thermal decomposition of substituted tetraoxanes in benzene solution: Effect of substituents on the activation parameters of the unimolecular reactions
Cafferata,Eyler,Svartman,Canizo,Bor kowski
, p. 1058 - 1061 (1990)
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Aromatization of dimethyl and diethyl ethers on Mo2C-promoted ZSM-5 catalysts
Kecskemeti, Anita,Barthos, Robert,Solymosi, Frigyes
, p. 111 - 120 (2008)
The adsorption and reaction pathways of dimethyl and diethyl ethers have been investigated on pure and Mo2C-containing ZSM-5. The catalysts have been characterized by XPS and surface acidity measurements. FTIR spectroscopic measurements indicated that a fraction of both ethers dissociates on pure and Mo2C-promoted zeolites already at 180-200 K resulting in the formation of methoxy from dimethyl ether, and ethoxy from diethyl ether. TPD experiments following the adsorption at 300 K showed desorption profiles corresponding to starting compounds and their decomposition products (methane, ethene and propene). ZSM-5 effectively catalyzed the reaction of dimethyl and diethyl ether above 473 K to yield various olefins and aromatics. From dimethyl ether xylene and from diethyl ether toluene were the main aromatic compounds. Adding Mo2C to the zeolites greatly promoted the formation of aromatics very likely by catalyzing the aromatization of olefins formed in the reaction of ethers on zeolites.
Reducing coke formation in the catalytic fast pyrolysis of bio-derived furan with surface modified HZSM-5 catalysts
Zhang, Bo,Zhong, Zhaoping,Xie, Qinglong,Chen, Paul,Ruan, Roger
, p. 56286 - 56292 (2015)
In order to reduce coke yield during catalytic fast pyrolysis of biomass, MgO and 2,4-dimethylquinoline (2,4-DMQ) were selected to reduce the number of external acid sites of HZSM-5. Both MgO and 2,4-DMQ deposition could cause a reduction in total acid sites (both weak acid sites and strong acid sites) and external acid sites of HZSM-5. The modified catalysts were used for the catalytic conversion of bio-derived furan. For the MgO/HZSM-5 catalyst, the effects of amount of MgO deposited and deposition time were studied. The carbon yields of aromatics, C2-C5 olefins, total chemicals, CO2 and CO increased at first and then decreased slightly when the deposited amount increased, while the carbon yield of coke decreased first and then increased gradually. Furthermore, as the deposited time increased, the carbon yields of petrochemicals, CO2 and CO increased greatly, whereas that of coke decreased. For the 2,4-DMQ/HZSM-5 catalyst, the effects of 2,4-DMQ treatment amount and treatment time were investigated. The experimental results showed that an increase in 2,4-DMQ treatment amount or treatment time could retard the generation of the target products, CO2 and CO but promote coke formation.
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Walling,Kjellgren
, p. 1488 (1969)
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TRANSFORMATIONS OF ISOBUTYLENE IN THE PRESENCE OF VARIOUS TYPES OF ZEOLITES
Kondrat'ev, D. A.,Bondarenko, T. N.,Dergachev, A. A.,Nefedov, B. K.,Alekseeva, T. V.,Minachev, Kh. M.
, p. 1034 - 1037 (1981)
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The catalytic effects of sulfur in ethane dehydroaromatization
Goodarzi, Farnoosh,Hansen, Lars P.,Helveg, Stig,Mielby, Jerrik,Nguyen, Thoa T. M.,Joensen, Finn,Kegn?s, S?ren
, p. 5378 - 5381 (2020)
In this work, we investigated the catalytic effect of adding sulfur on Zn/ZSM-5 catalyst for direct conversion of ethane to aromatics. We show that the continuous addition of hydrogen sulfide (H2S) effectively stabilizes zinc, prevents coking and results in a highly selective and stable catalyst. Considering the high content of sulfur in shale gas resources, these results highlight the importance of investigating catalysts under realistic operating conditions.
Kinetic Isotope Effects in Hydrogen Atom Transfer Reactions between Benzylic Carbons
Bockrath, Bradley C.,Bittner, Edward W.,Marecic, Thomas C.
, p. 15 - 19 (1986)
The kinetic deuterium isotope effect for transfer of hydrogen from tetralin, dihydroanthracene, fluorene, diphenylmethane, triphenylmethane, and acenaphthene to the benzyl radical was measured at 170 deg C.The range of values for the effect was from 6.5 to 8.0.Activation energy parameters were obtained for five of the hydrogen donors.The apparent difference between activation energies for deuterium or hydrogen transfer was 2 kcal/mol for triphenylmethane, diphenylmethane, and tetralin.Applications of several tests indicate that a tunnel effect plays a significant role in these hydrogen transfers.
Effect of Pressure on the Electron Mobility in Liquid Benzene and Toluene
Itoh, Kengo,Holroyd, Richard
, p. 8850 - 8854 (1990)
High pressure causes a decrease of the mobility of excess electrons in both benzene and toluene.These decreases are interpreted as a shift in the equilibrium e-s + A A- in favor of the anions (A-) at high pressure.These attachment reactions are favored at high pressure by large negative volume changes of between -100 and -180 cm3/mol, which are attributed to electrostriction of the solvent by the anion.Above 1.5 kbar the mobility becomes independent of pressure.Transport under these conditions involves electron hopping from the anion to a neighboring molecule.
Electrochemical Initiation of Aromatic SRN1 Reactions Using Redox Catalysts
Swartz, James E.,Stenzel, Timothy T.
, p. 2520 - 2524 (1984)
Electrochemical reduction of benzonitrile in the presence of bromobenzene and tetra-N-butylammonium benzenethiolate in dimethyl sulfoxide (Me2SO) forms diphenyl sulfide (67percent) and benzene (38percent).The reaction consumes 0.37 faraday per mol of bromobenzene, indicating that an SRN1 chain reaction is occuring.Reaction in Me2SO-d6 gives a decreased yield of benzene (17percent), 57percent of which was monodeuterated, which along with coulometric data indicates that a major termination pathway is abstraction of hydrogen atoms from Me2SO by phenyl radicals.Photoinitiated reactions in the presence and absence of tetra-N-butylammonium ions indicate that they are also a significant source of hydrogen atoms in termination.Evidence from reactions of 4-bromotoluene with benzenethiolate ion indicates that fragmentation of the diaryl sulfide radical anion intermediate is an important reaction in these systems.The presence of benzonitrile suppresses that cleavage.
Nonoxidative Direct Conversion of Methane on Silica-Based Iron Catalysts: Effect of Catalytic Surface
Han, Seung Ju,Lee, Sung Woo,Kim, Hyun Woo,Kim, Seok Ki,Kim, Yong Tae
, p. 7984 - 7997 (2019)
For a stable methane to olefins, aromatics, and hydrogen (MTOAH) reaction, 0.27-0.43 wt % Fe-containing silica catalysts were synthesized through various preparation methods and tested. The presence of Fe species in SiO2 mixtures increased the true and apparent densities of the catalysts during the melt-fusing process at 1700 °C. Several characterizations (i.e., H2-TPR, TEM, and XAS) revealed that partially reduced iron oxide (Fe3O4) predominantly existed in cristobalite (CRS) in the melt-fused catalysts. The FeCRS catalyst prepared from fayalite and quartz by the melt-fusing method showed a higher resistance to structural sintering and coke deposition than other Fe catalysts during MTOAH at 1020 °C. It also showed a 40% higher apparent activation energy for coke formation than for methane consumption in the temperature range of 1000 to 1040 °C. Increased CRS surfaces increased the coke selectivity, indicating that even the pure CRS surface acts as a chain reaction terminator to form coke. At the same space velocity (9400 h-1), the FeCRS catalyst was more selective in producing C2 (ethane, ethylene, and acetylene), C3-C5 olefins, and aromatics than pure CRS and other Fe catalysts. At a steady state, the FeCRS surface was most suitable for methane conversion, being 2.3 times more efficient than without a catalytic surface. The FeCRS catalyst exhibited a stable activity and low coke selectivity, even for 50 h, in the MTOAH reaction. EXAFS profiles showed that highly dispersed Fe carbide with Fe-Si coordination was formed in the FeCRS catalyst, and electronic structure calculations indicated that these confined Fe sites were more favorable for methyl radical formation and a high coke resistance than Fe3C clusters. By optimizing reaction parameters, the FeCRS catalyst exhibited 6.9-5.8% methane conversion and 86.2% C2 selectivity for 100 h with cofeeding of 50% H2 at 1080 °C.
Correlation of the catalytic performance with Nb2O5 surface properties in the hydrodeoxygenation of lignin model compound
Xin, Yu,Dong, Lin,Guo, Yong,Liu, Xiaohui,Hu, Yongfeng,Wang, Yanqin
, p. 202 - 212 (2019)
Production of aromatic hydrocarbons through lignin hydrodeoxygenation (HDO) is of significant importance. Previously, we found that Ru/Nb2O5 was an excellent catalyst for the conversion of lignin to arenes with relatively high selectivity (71%). Herein, we aim to clarify which properties of Nb2O5 influence the activity and selectivity. Four Ru/Nb2O5 catalysts with different Nb2O5 morphologies were used in the HDO of 4-methylphenol. Intensive studies show that layered Nb2O5 supported Ru has more Nb[dbnd]O groups (unsaturated NbOx sites) and highest Ru dispersion, which led to the highest activity and toluene selectivity, this was further confirmed by loading pre-synthesized Ru colloids in various Nb2O5. Finally, a Ru/Nb2O5 catalyst with more unsaturated Nb[dbnd]O groups was designed and it was found that even with enzymatic lignin as the feedstock, the selectivity to arenes can reach up to 94.8% with the yield of hydrocarbons of 99.6%. This study provides a promising strategy for catalyst design towards the selective production of aromatic hydrocarbons from lignin.
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van Tamelen et al.
, p. 7113 (1971)
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The application of a supported palladium catalyst for the hydrogenation of aromatic nitriles
McMillan, Liam,Gilpin, Lauren F.,Baker, Justin,Brennan, Colin,Hall, Alan,Lundie, David T.,Lennon, David
, p. 239 - 246 (2016)
The use of a Pd/C catalyst in the liquid phase hydrogenation of various aromatic nitriles (benzonitrile, benzyl cyanide, 3-phenyl propionitrile and cinnamonitrile) has been studied in order to assess the effectiveness of this type of catalyst for this class of reaction. On modifying the nitrile substituent and upon introducing conjugation, varying degrees of conversion are observed. For benzyl cyanide and 3-phenylpropionitrile, incomplete mass balance profiles are linked to spill-over to the carbon support. In the case of benzonitrile hydrogenation, a hydrogenolytic step leads to a loss of selectivity to the primary amine to yield toluene with, ultimately, complete selectivity. Co-hydrogenation measurements on mixtures of benzonitrile and benzylamine indicate the presence of site-selective chemistry. Co-hydrogenation studies on mixtures of benzonitrile and benzyl cyanide highlight the competitive nature of the reaction system and, indirectly, establish a contribution from adsorbed imine species.
Non-oxidative reactions of propane on Zn/Na-ZSM5
Biscardi, Joseph A.,Iglesia, Enrique
, p. 5753 - 5759 (1999)
Propene formation rates during propane conversion at 773 K on Zn/Na-ZSM5 are about ten times higher than on Zn/H-ZSM5 catalysts with similar Zn content. The total rate of propane conversion is also higher on Zn/Na-ZSM5 by a factor of four. Propane reactions lead to high propene selectivities (> 50%) as protons are replaced by Na cations in Zn/H-ZSM5 catalysts. The titration of acid sites with Na+ cations decreases the rate of acid- catalyzed chain growth reactions and the selectivity to C6-C9 aromatics. X- ray absorption studies at the Zn-K edge showed that aqueous ion exchange of Na-ZSM5 with Zn cations leads to isolated (ZnOH)+ species located at cation exchange sites. Unlike Zn species in Zn/H-ZSM5 (+ species with neighboring zeolite OH groups are less likely to occur in Zn/Na-ZSM5 and most Zn species remain as (ZnOH)+. Temperature programmed reduction studies show that Zn species in Zn/Na-ZSM5 reduce at lower temperatures than the (O-Zn2+-O-) species present in Zn/H-ZSM5. D2 exchange with surface OH groups showed that some protons are formed during ion exchange. Higher deuterium contents in products of C3H8-D2 mixtures on Zn/Na-ZSM5 suggest that (ZnOH)+ species in Zn/Na- ZSM5 catalyze rate-determining hydrogen desorption steps during propane conversion more effectively than (O-Zn2+-O-) sites present in Zn/H-ZSM5. The presence of (ZnOH)+ species and a lower acid site density in Zn/Na-ZSM5 leads to much higher propane conversion rates than on Zn/H-ZSM5. As the acid site density decreases, propene aromatization rates decrease, which leads to less hydrogen to be disposed by a more efficient hydrogen recombinative desorption species (ZnOH)+.
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Saegusa et al.
, p. 4182 (1968)
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Oxidative dehydrogenation of cyclohexane and cyclohexene over supported gold, palladium and gold-palladium catalysts
Dummer, Nicholas F.,Bawaked, Salem,Hayward, James,Jenkins, Robert,Hutchings, Graham J.
, p. 2 - 6 (2010)
Supported gold, palladium and gold-palladium catalysts have been used to oxidatively dehydrogenate cyclohexane and cyclohexenes to their aromatic counterpart. The supported metal nanoparticles decreased the activation temperature of the dehydrogenation reaction. We found that the order of reactivity was Pd ≥ Au-Pd > Au supported on TiO2. Attempts were made to lower the reaction temperature whilst retaining high selectivity. The space-time yield of benzene from cyclohexane at 473 K was determined to be 53.7 mol/kgcat/h rising to 87.3 mol/kgcat/h at 673 K for the Pd catalyst. Increasing the temperature in this case improved conversion at a detriment to the benzene selectivity. Oxidative dehydrogenation of cyclohexene over AuPd/TiO2 or Pd/TiO2 catalysts was found to be very effective (conversion >99% at 423 K). These results indicate that the first step in the reaction sequence of cyclohexane to cyclohexene is the slowest step. These initial results suggest that in a fixed-bed reactor the oxidative dehydrogenation in the presence of oxygen, palladium and gold-palladium catalysts are readily able to surpass current literature examples and with further modification should yield even higher performance.
Metal-Free Photocatalytic Reductive Dehalogenation Using Visible-Light: A Time-Resolved Mechanistic Study
Martinez-Haya, Rebeca,Miranda, Miguel A.,Marin, M. Luisa
, p. 2164 - 2169 (2017)
The reductive dehalogenation of organic bromides has been achieved in the presence of riboflavin (RF) as photocatalyst under visible-light irradiation. Specifically, benzyl bromide (2) and α-bromoacetophenone (3) were quantitatively converted into toluene and acetophenone, respectively, by using amines as electron donors and iPrOH as hydrogen donor, whereas bromobenzene (1) did not react. The thermodynamics of the reduction of the radical anion of RF were evaluated by using the redox potentials of the species involved: The reaction was found to be thermodynamically exergonic for 2 and 3, but not expected to occur for bromobenzene (1). The viability of the different competing processes on the timescales of the corresponding singlet and triplet RF excited states (1RF* and 3RF*) was analyzed by time-resolved techniques. The quenching of 1RF* by amines was very efficient, and comparison of the transient absorption spectra recorded in the absence and presence of amines additionally confirmed the efficient redox process between 1RF* and the amines. Moreover, RF·– was quenched by bromides 2 and 3, but not by 1. Thus, a deeper understanding of the overall mechanism of the photocatalytic reductive reaction has been achieved, and the key role of the radical anion of the photocatalyst has been demonstrated.
Efficient hydrogenolysis of aryl ethers over Ce-MOF supported Pd NPs under mild conditions: mechanistic insight using density functional theoretical calculations
Kar, Ashish Kumar,Kaur, Surinder Pal,Kumar, T. J. Dhilip,Srivastava, Rajendra
, p. 6892 - 6901 (2020)
Selective hydrogenolysis of lignin-derived aryl ethers under mild temperature and pressure conditions is an important milestone to be achieved to fulfill the future fuel demands from abundantly available biomass resources. Selective hydrogenolysis requires precise modulation of surface active sites of the catalyst to obtain the desired activity and selectivity. In this study, the selective hydrogenolysis of benzyl phenyl ether to phenol and toluene is achieved in methanol and water medium at a very low temperature and low H2 pressure over a Pd nanoparticle decorated Ce-BTC metal-organic framework. The activity of the developed catalyst is two times higher than that of Pd decorated CeO2. The structure-activity relationship is established using catalytic measurements, X-ray photoelectron spectroscopy, and transmission electron microscopy. The mechanistic insight into the hydrogenolysis of aryl ethers and the reasons behind the superior activity of Pd/Ce-BTC to that of Pd/CeO2 are investigated using density functional theoretical (DFT) calculations. Spectroscopic measurements and DFT calculations suggest that the higher Pd0/Pd2+ ratio and higher adsorption of benzyl phenyl ether over Pd/Ce-BTC and the higher adsorption of phenol over Pd/CeO2 are factors responsible for the higher activity of Pd/Ce-BTC than that of Pd/CeO2. Efficient recyclability and hot filtration tests reveal that the catalyst exhibits no noteworthy loss in the activity after five consecutive cycles. The Pd/Ce-BTC catalyst displays a very high turnover frequency and low activation energy, which are very attractive from the industrial perspective and academic point of view. This journal is
One-Pass Conversion of Benzene and Syngas to Alkylbenzenes by Cu–ZnO–Al2O3 and ZSM-5 Relay
Han, Tengfei,Xu, Hong,Liu, Jianchao,Zhou, Ligong,Li, Xuekuan,Dong, Jinxiang,Ge, Hui
, p. 467 - 479 (2021/05/21)
Alkylbenzenes have a wide range of uses and are the most demanded aromatic chemicals. The finite petroleum resources compels the development of production of alkylbenzenes by non-petroleum routes. One-pass selective conversion of benzene and syngas to alkylbenzenes is a promising alternative coal chemical engineering route, yet it still faces challenge to industrialized applications owing to low conversion of benzene and syngas. Here we presented a Cu–ZnO–Al2O3/ZSM-5 bifunctional catalyst which realizes one-pass conversion of benzene and syngas to alkylbenzenes with high efficiency. This bifunctional catalyst exhibited high benzene conversion (benzene conversion of 50.7%), CO conversion (CO conversion of 55.0%) and C7&C8 aromatics total yield (C7&C8 total yield of 45.0%). Characterizations and catalytic performance evaluations revealed that ZSM-5 with well-regulated acidity, as a vital part of this Cu–ZnO–Al2O3/ZSM-5 bifunctional catalyst, substantially contributed to its performance for the alkylbenzenes one-pass synthesis from benzene and syngas due to depress methanol-to-olefins (MTO) reaction. Furthermore, matching of the mass ratio of two active components in the dual-function catalyst and the temperature of methanol synthesis with benzene alkylation reactions can effectively depress the formation of unwanted by-products and guarantee the high performance of tandem reactions. Graphic Abstract: [Figure not available: see fulltext.]
Selective catalytic synthesis of bio-based high value chemical of benzoic acid from xylan with Co2MnO4@MCM-41 catalyst
Fan, Minghui,He, Yuting,Li, Quanxin,Luo, Yuehui,Yang, Mingyu,Zhang, Yanhua,Zhu, Lijuan
, (2021/12/20)
The efficient synthesis of bio-based chemicals using renewable carbon resources is of great significance to promote sustainable chemistry and develop green economy. This work aims to demonstrate that benzoic acid, an important high added value chemical in petrochemical industry, can be selectively synthesized using xylan (a typical model compound of hemicellulose). This novel controllable transformation process was achieved by selective catalytic pyrolysis of xylan and subsequent catalytic oxidation. The highest benzoic acid selectivity of 88.3 % with 90.5 % conversion was obtained using the 10wt%Co2MnO4@MCM-41 catalyst under the optimized reaction conditions (80 °C, 4 h). Based on the study of the model compounds and catalyst's characterizations, the reaction pathways for the catalytic transformation of xylan to bio-based benzoic acid were proposed.
Hydrodeoxygenation of lignin and its model compounds to hydrocarbon fuels over a bifunctional Ga-doped HZSM-5 supported metal Ru catalyst
Cao, Jing-Pei,Jiang, Wei,Xie, Jin-Xuan,Yang, Zhen,Zhang, Chuang,Zhang, Jian-Li,Zhao, Liang,Zhao, Xiao-Yan,Zhao, Yun-Peng,Zhu, Chen
, (2022/02/14)
Hydrodeoxygenation (HDO) of lignin to value-added biofuels and chemicals has a great significance for the advanced utilization of renewable lignocelluloses and the future biobased economy but is always a big challenge. Herein, a Ga-doped HZSM-5 supported metal Ru catalyst (bifunctional Ru/Ga-HZSM-5) exhibited the excellent HDO performance for converting diphenyl ether (DPE) to produce the only product, i.e., cyclohexane, under extremely mild conditions (180 °C, 1 MPa H2 and 2 h). The oxygen-containing group in DPE was mainly removed through the cleavage of the C-O ether bond, followed by metal- and acid-catalyzed comprehensive hydrogenation and deoxygenation. Further characterization results confirmed that the doping of Ga remarkably enhanced the interaction between the metal Ru and the support. For the depolymerization of real lignin, Ru/Ga-HZSM-5 could not only significantly improve the total liquid yield of lignin, but also convert the oxygen-containing species into the aliphatic hydrocarbons.