Benzene Conversion Research Articles

Structural Characteristics of the Resin–Asphaltene Components of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit and the Liquid Products of Its Conversion in Supercritical Benzene

Structural Characteristics of the Resin–Asphaltene Components of the Organic Matter of Oil Shale from the Dmitrievskoe Deposit and the Liquid Products of Its Conversion in Supercritical Benzene

Vacuum-assisted continuous flow electroless plating approach for high performance Pd membrane deposition on ceramic hollow fiber lumen

Pd-based membranes have wide applications in H2-related fields given their excellent selectivity in H2 separation. Despite their unique advantages, the fabrication of continuous and dense Pd membrane layer in the lumen side of the hollow fibers remains a great challenge. Herein, a vacuum-assisted continuous flow electroless plating (VCFELP) approach was developed to deposit a 4 μm-thick compact Pd membrane layer on the lumen (i.e., inner surface) of YSZ-Al2O3 composite hollow fiber with outer and inner diameter of 1.5 and 1.0 mm, respectively. The Pd membrane displayed hydrogen flux of ∼0.075 mol m−2 s−1 at 773 K and the nitrogen was undetectable through bubble flow meter and gas chromatograph. Furthermore, the stability and durability of the Pd membrane were significantly improved by the VCFELP approach with the aid of vacuum and continuous flow system. The outstanding membrane stability was verified by the 240-h long-term operation, with up to 24 cycles of H2–N2 gas exchange tests, 40 thermal cycle tests (from high to low temperature) and 20 pressure cycle tests. Furthermore, the Pd membrane showed sufficient stability and excellent reaction performance during the 120-h reaction run in the one-step oxidation of benzene to phenol using hydrogen and oxygen as co-reactants, achieving the benzene conversion and phenol selectivity of 23.5% and 91.6%, respectively.

Mechanism of synergistic effects and kinetic analysis in bamboo-LDPE waste ex-situ catalytic co-pyrolysis for enhanced aromatic hydrocarbon production via CeZrAl and HZSM-5 dual catalyst

Thermocatalytic co-pyrolysis of agro-forestry residue and LDPE waste was used to improve aromatic-rich bio-oil with combining CeZrAl and HZSM-5 dual catalyst. The influence of pyrolysis parameters on pyrolysis characteristics, kinetics, aromatic yield and selectivity was investigated; the synergistic effect and additive effect for promoting aromatic hydrocarbons with and without catalysts were determined based on the experimental and theoretical hydrocarbon content; and the reaction mechanism was also described by analyzing the free radicals. Experimental results showed that LDPE with a higher H/Ceff ratio promoted biomass pyrolysis to produce aromatic-rich bio-oil with mass transfer and radical explanation. Dual catalytic co-pyrolysis remarkably increased hydrocarbon and aromatic hydrocarbon (AHs) contents. When the proportion of HZSM-5 was greater than 50%, the layered mode was more conducive to the formation of aromatics and more conducive to the conversion of alkyl benzene, while the mixed mode was more conducive to the conversion of olefins with a higher CeZrAl ratio, which facilitated the formation of toluene, xylene, BTXE and MAHs. The optimum aromatic, BTXE and MAH yields and selectivity (88.49%, 59.48% and 68.00%) were observed at 500/550 °C for a 1:2 CeZrAl to HZSM-5 ratio and a biomass to LDPE ratio. Abundant free radicals were produced and improved the mechanism’s synergistic effect.

Uniform single atomic Cu1-C4 sites anchored in graphdiyne for hydroxylation of benzene to phenol.

ABSTRACTFor single-atom catalysts (SACs), the catalyst supports are not only anchors for single atoms, but also modulators for geometric and electronic structures, which determine their catalytic performance. Selecting an appropriate support to prepare SACs with uniform coordination environments is critical for achieving optimal performance and clarifying the relationship between the structure and the property of SACs. Approaching such a goal is still a significant challenge. Taking advantage of the strong d-π interaction between Cu atoms and diacetylenic in a graphdiyne (GDY) support, we present an efficient and simple strategy for fabricating Cu single atoms anchored on GDY (Cu1/GDY) with uniform Cu1-C4 single sites under mild conditions. The Cu atomic structure was confirmed by combining synchrotron radiation X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and density functional theory (DFT) calculations. The as-prepared Cu1/GDY exhibits much higher activity than state-of-the-art SACs in direct benzene oxidation to phenol with H2O2 reaction, with turnover frequency values of 251 h−1 at room temperature and 1889 h−1 at 60°C, respectively. Furthermore, even with a high benzene conversion of 86%, high phenol selectivity (96%) is maintained, which can be ascribed to the hydrophobic and oleophyllic surface nature of Cu1/GDY for benzene adsorption and phenol desorption. Both experiments and DFT calculations indicate that Cu1-C4 single sites are more effective at activating H2O2 to form Cu=O bonds, which are important active intermediates for benzene oxidation to phenol.

Steam reforming of biomass tar model compound over two waste char-based Ni catalysts for syngas production

The removal of biomass tar is the key technology in the pyrolysis and gasification technology, and the advantages of solid waste pyrolysis char in tar removal gradually become prominent. In this paper, the tar model compound (benzene) was catalytic reformed by a novel hybrid carrier catalysts using a laboratory dual-stage reactor. The hybrid carrier catalyst was prepared by wet impregnation method with nickel active substance, and the carrier was a two-material mixture of peat char and sludge char. In the reaction of steam reforming benzene, the effects of temperature (600–800 °C) and nickel load (5%–20%) on benzene conversion were investigated, showing that the catalyst have good benzene removal ability (91.8%) and the gas product with high syngas content (93.6%) was obtained. The surface properties of the catalyst was detected by SEM, EDS, BET and XRD detection, in order to prove that the catalytic performance was related to surface nanoparticles and abundant active sites. The novel hybrid carrier catalyst can effectively remove the aromatic tar and produce syngas with high performance.

Real coupling of solid oxide fuel cells with a biomass steam gasifier: Operating boundaries considering performance, tar and carbon deposition analyses

Solid oxide fuel cells are a promising alternative to gas engines for combined heat and power production based on biomass gasification. The technical complexity of realizing gasifier – fuel cell couplings has limited the number of experiments conducted in the past. However, results from such experiments are of high importance for the evaluation of tar thresholds and operating conditions ensuring a stable operation of fuel cells. For the first time, it was possible to demonstrate for dozens of hours the operation of solid oxide fuel cells with real product gas from steam gasification with a steam-to-carbon ratio of 2 and a typical tar content for fluidized bed gasification. Four coupling experiments with industrial-relevant cell designs were conducted, demonstrating a stable operation for 30 h without structural degradation of the anodes for cells with nickel/ceria- and nickel/zirconia-based anodes at 800°C and 850°C, if heavy tars were partially removed (2.8–3.7 g·Nm−3 gravimetric tars). Raw gas operation (4.6–4.8 g·Nm−3 gravimetric tars) led to metal dusting effects on nickel contact meshes and nickel/zirconia-based anodes, whereas nickel/ceria-based anodes were less affected. Carbon deposited on the alumina support in all experiments whereby a change from pyrolytic to graphitic structure could be observed when increasing the temperature from 800°C to 850°C, thus significantly reducing the risk for blockages in the flow channels. Moreover, high tar and benzene conversion rates were observed. Concluding, operating temperatures of 850°C and the removal only of heavy tars can enable stable long-term operation with a tar-laden steam gasifier product gas, even without increasing the steam-to-carbon ratio to values exceeding two.

Advances in Catalytic Conversion of Benzene to Phenol using N2O as Oxidant

Advances in Catalytic Conversion of Benzene to Phenol using N2O as Oxidant

Catalytic oxidation of VOCs over 3D@2D Pd/CoMn2O4 nanosheets supported on hollow Al2O3 microspheres

Catalytic oxidation is a promising method for removing harmful volatile organic compounds (VOCs). Therefore, exploring high-efficiency catalysts for catalyzing VOCs is of great significance to the realization of an environment-friendly and sustainable society. Here, a series of 3D@2D constructed Al2O3@CoMn2O4 microspheres with a hollow hierarchical structure supporting Pd nanoparticles was successfully synthesized. The introduction of hollow Al2O3 for the in situ vertical growth of 2D CMO spinel materials constructs a well-defined core − shell hollow hierarchical structure, leading to larger specific surface area, more accessible active sites and promoted catalytic activity of support material. Additionally, theoretical calculations also indicate that the addition of Al2O3 as the support material strengthens the adsorption of toluene and oxygen on CoMn2O4, which promotes their activation. The dispersion of Pd further strengthens the low-temperature reducibility along with more active surface oxygen species and lower apparent activation energy. The optimum 1 wt% Pd/h-Al@4CMO catalyst possesses the lowest apparent activation energy for toluene of 77.4 kJ mol−1, showing the relatively best catalytic activity for VOC oxidation, reaching 100% toluene, benzene, and ethyl acetate conversion at 165, 160, and 155 °C, respectively. Meanwhile, the 1 wt% Pd/h-Al@4CMO sample possesses excellent catalytic stability, outstanding selectivity, and good moisture tolerance, which is an effective candidate for eliminating VOCs contaminants.

In situ ortho-lithiation/functionalization of pentafluorosulfanyl arenes.

A general method for ortho-functionalization of pentafluorosulfanyl arenes has been developed. ortho-Lithiation with lithium tetramethylpiperidide at -60 °C in the presence of silicon, germanium, and tin electrophiles affords trapped products in moderate to high yields. Precise temperature regimes and the presence of electrophiles during lithiation are important for successful reactions, since the pentafluorosulfanyl group acts as a competent leaving group at temperatures above -40 °C. Fluoro, bromo, iodo, enolizable keto, cyano, ester, amide, and unsubstituted amino functionalities are compatible with the reaction conditions. Conversion of 2-dimethylsilylpentafluorosulfanyl benzene to 2-halosubstituted derivatives, useful as starting materials in cross-coupling chemistry, was also demonstrated.

Characterization of Surface Species during Benzene Hydroxylation over a NiO-Ceria-Zirconia Catalyst.

NiO/ceria-zirconia (CZ) is a promising catalyst for the selective oxidation of benzene, as the Lewis-acidic NiO clusters can activate C-H bonds and the redox-active CZ support can activate O2 and supply active oxygen species for the reaction. In this study, we used transmission in situ infrared (IR) spectroscopy to examine surface species formed from benzene, water, oxygen, phenol, and catechol on a NiO/CZ catalyst. The formation of surface species from benzene and phenol was compared at different temperatures in the range of 50-200 °C in the presence and absence of water vapor. We also examined the role of the NiO clusters and the CZ support during benzene activation by comparing the surface species formed on NiO-CZ with those formed on a Ni-free CZ support and on a NiO/SiO2 catalyst. The spectrum of surface species from dosing benzene at 180 °C provides evidence for C-H bond activation. Specifically, the observation of C-O stretching vibrations indicates the formation of phenolate species. Introduction of water enhances these IR signals and introduces several additional peaks, indicating that a variety of different surface species are formed. These results show that NiO/CZ could catalyze direct conversion of benzene to phenol.

Experimental and density functional theory investigations on the oxidation of typical aromatics over the intermetallic compounds-derived AuMn/meso-Fe2O3 catalysts

Aromatic volatile organic compounds (VOCs) are usually pollutants to the atmosphere environment and human health. In the present work, we first adopted the co-reduction and KIT-6-templating strategies to prepare the AuxMny intermetallic compounds and mesoporous iron oxide (meso-Fe2O3), respectively, and then used the impregnation method to generate the AuxMny/meso-Fe2O3 catalysts. Catalytic performance of these materials was evaluated for benzene, toluene or o-xylene (typical aromatics) oxidation. It is found that the Au5Mn2/meso-Fe2O3 catalyst exhibited the best activity: the temperatures at benzene conversions of 50 and 90 % were 237 and 254 °C at a space velocity of 20,000 mL/(g h), with the TOFAu values and specific reaction rates at 210 and 230 °C being 1.08 and 2.29 s−1, and 6.92 and 11.58 mmol/(gAu s), respectively. Such excellent performance of Au5Mn2/meso-Fe2O3 was related to its well dispersed Au5Mn2 nanoparticles, high adsorbed oxygen species concentration, good low-temperature reducibility, high benzene adsorption capacity, and strong benzene adsorption. The benzene chemisorption mechanism and adsorbed oxygen species could greatly influence the oxidation of benzene. According to the first-principles calculations, we find that benzene adsorption on the surface of Au in Au5Mn2/meso-Fe2O3 was in the form of a π bond, in which the Au could obtain electrons from benzene ring in the presence of benzene adsorption, resulting in a stronger adsorption of benzene and thus increasing the catalytic activity for benzene oxidation. The mechanism of benzene oxidation might take place via the route of benzene → phenol → benzoquinone → maleate (acetate) → carbon dioxide and water.

Novel Vanadia/meso-Co3O4 catalysts for the conversion of benzene–toluene–xylene to environmental friendly components via catalytic oxidation

ABSTRACT Three – dimensional meso-porous Co3O4 was prepared by nanocasting pathway based on the use of mesoporous silica (KIT-6) as hard template with different Cobalt concentrations (0.5–2.5 mol ratio based on mesoporous silica KIT-6). The prepared samples was used as supports for preparing V2O5/Co3O4 (1, 6 wt% of V2O5) catalysts. The prepared samples were characterized by different techniques. The catalytic activity of the prepared samples were evaluated in the complete oxidation reaction of toluene, benzene, and/or p-xylene; (as model reactants of volatile organic compounds) in terms of CO2. The catalytic reaction was carried out in a fixed-bed micro-reactor operated under atmospheric pressure and within the reaction temperature range of 200–400 °C. The data confirmed that the three dimensional-mesoporous Co3O4 (1.0 mole ratio) replicated sample possessed improved different parameters compared to those of the Co3O4 sample with other mole ratios. The data reflected the yield of Co2 is decreased upon the increase in reaction temperature to 400°C. 1 wt.% V2O5/m-Co3O4 catalyst shows a reverse direction, the CO2 yield slowly increased in the range 150–250 °C, then jumped at 300 °C until maximum yield (100%) is observed at 400 °C. 1 wt.% V2O5/m-Co3O4 catalyst was found to be the active and selective promised catalyst for the complete oxidation of either individual aromatic volatile organic compounds (benzene, toluene, and/or xylene) and/or their mixtures to 100% CO2.

Ethyl benzene oxidation under aerobic conditions using cobalt oxide imbedded in nitrogen-doped carbon fiber felt wrapped by spiral TiO2-SiO2

Carbon fiber felt (CFF) as a carbonaceous framework has received great attention in catalysis applications. In this work, a novel nanocomposite composed of cobalt oxide micro-sized particles (MPs) incorporated in nitrogen-doped carbon and wrapped by coil-like TiO2-SiO2 layer was fabricated through a co-assembly protocol including MPs implanting, hydrolysis and calcination steps. The structural properties and performance of the prepared Co/N-CFF@TiO2-SiO2 catalyst was evaluated by different techniques. Mechanical, chemical and thermal stabilities of CFF were stepwise improved and the results explain how the N-CFF matrix and strong spiral envelope promoted textural features in the final composite. Moreover, the catalyst exhibited good activity in oxidation of ethyl benzene by molecular oxygen. Under optimized conditions (130 °C, 12 h, 5 mL of ethylbenzene, 20 bar O2 pressure), the ethyl benzene conversion and acetophenone selectivity were 25% and 88%, respectively. The novel Co/N-CFF@TiO2-SiO2 catalyst showed excellent long-term stability over 6 consecutive cycles, which permits to consider it as an ideal platform for application at industrial scales due to its green and bulk nature.

Ethylene and cyclohexane co-production in the fixed-bed catalytic membrane reactor: Experimental study and modeling optimization

In this study, a fixed-bed catalytic membrane reactor was used for the production of ethylene and cyclohexane from ethane and benzene. A two-dimensional non-isothermal mathematical model was used for estimating the performance of the membrane reactor. Furthermore, the effect of inlet temperature (720–1080 K), feed molar ratio (3–10) and the reactor spacetime (1–76 kgCat.s/mol) was studied on the conversion of ethane to ethylene and benzene to cyclohexane. The results of modeling showed that with the increase of inlet temperature the conversion of both (de)-hydrogenation reactions increased and the 95% of ethane conversion was achieved when the molar ratio of benzene/ethane was fixed on 3. The hydrogenation of benzene at the shell side of the catalytic membrane reactor enhanced the production of ethylene due to the exothermic nature of the hydrogenation reaction, resulting in heat conduction through the membrane and glass substrate into the tube side. The comparison between experimental data reported in literature and modeling showed that the deviation of data obtained by mathematical modeling from experimental values ranged from 15.2 to 19.8% at various spacetimes. In addition, the results of sensitivity analysis showed that the conversion of benzene and ethane is more sensitive to the inlet temperature (up to 160% change on conversion) in comparison to the other parameters including feed ratio and the reactor spacetime. Moreover, at a temperature above 1128 K, the overall performance of the catalytic membrane reactor increased significantly.

Mechanochemically Prepared Co3O4-CeO2 Catalysts for Complete Benzene Oxidation

Considerable efforts to reduce the harmful emissions of volatile organic compounds (VOCs) have been directed towards the development of highly active and economically viable catalytic materials for complete hydrocarbon oxidation. The present study is focused on the complete benzene oxidation as a probe reaction for VOCs abatement over Co3O4-CeO2 mixed oxides (20, 30, and 40 wt.% of ceria) synthesized by the more sustainable, in terms of less waste, less energy and less hazard, mechanochemical mixing of cerium hydroxide and cobalt hydroxycarbonate precursors. The catalysts were characterized by BET, powder XRD, H2-TPR, UV resonance Raman spectroscopy, and XPS techniques. The mixed oxides exhibited superior catalytic activity in comparison with Co3O4, thus, confirming the promotional role of ceria. The close interaction between Co3O4 and CeO2 phases, induced by mechanochemical treatment, led to strained Co3O4 and CeO2 surface structures. The most significant surface defectiveness was attained for 70 wt.% Co3O4-30 wt.% CeO2. A trend of the highest surface amount of Co3+, Ce3+ and adsorbed oxygen species was evidenced for the sample with this optimal composition. The catalyst exhibited the best performance and 100% benzene conversion was reached at 200 °C (relatively low temperature for noble metal-free oxide catalysts). The catalytic activity at 200 °C was stable without any products of incomplete benzene oxidation. The results showed promising catalytic properties for effective VOCs elimination over low-cost Co3O4-CeO2 mixed oxides synthesized by simple and eco-friendly mechanochemical mixing.

Study of catalytic hydrogenation performance for the Pd/CeO2 catalysts

Abstract Pd/CeO2 catalysts with different metallic Pd loading were synthesized by impregnation method. The physicochemical properties of prepared Pd/CeO2 catalysts and corresponding precursors were studied by XRD, XPS, H2-TPD and H2-TPR. Moreover, the catalytic performance of the Pd/CeO2 catalysts was investigated via gas phase benzene hydrogenation reaction at the temperature of 100–200 °C under atmosphere pressure. Results show that the catalytic performance of prepared Pd/CeO2 catalysts is directly related to the metallic Pd content. The amounts of active metallic Pd and adsorbed-desorbed hydrogen species on Pd/CeO2 catalysts increase with the increasing metallic Pd loading from 1.0 to 3.0%, while the numbers of them are slightly reduced on Pd/CeO2(3.5) catalyst. Furthermore, metallic Pd is highly dispersed on the nano-CeO2 supports, therefore, the prepared Pd/CeO2 catalysts present good gas phase benzene catalytic hydrogenation performance. At 200 °C, the benzene conversion over the Pd/CeO2 catalysts with different metallic Pd loading follows the rule: Pd/CeO2(3.0) > Pd/CeO2(3.5) > Pd/CeO2(2.5) > Pd/CeO2(2.0) > Pd/CeO2(1.5) > Pd/CeO2(1.0), corresponding values are 94.3, 96.4, 89.9, 82.8, 72.7, 42.6 and 94.3%. And the cyclohexane selectivity is 100% on all prepared Pd/CeO2 catalysts.

Benzene conversion using a partial combustion approach in a packed bed reactor

This study investigates the partial combustion technique for tar conversion using a modified experimental set up comprising a packed bed reactor with bed-inside probe for air supply. Simulated producer gas (SPG) and benzene were selected as a real producer gas alternative and model tar component respectively. The benzene conversion was investigated under different experimental conditions such as reactor temperature (650–900 °C), packed bed height (0–12 cm), residence time (1.2–1.9 s), air fuel ratio (0.2 and 0.3) and SPG composition. The results showed insignificant effect of temperature over benzene conversion while air fuel ratio of 0.3 caused high benzene conversion than at 0.2. Absence of packed bed lead high benzene conversion of 90% to polyaromatic hydrocarbons (PAHs) compared to similar low PAHs free benzene conversion of 32% achieved at both packed heights. In SPG composition effect, H2 and CH4 had a substantial inverse effect on benzene conversion. An increase in H2 concentration from 12 to 24 vol% increased the benzene conversion from 26 to 45% while an increase in CH4 concentration from 7 to 14 vol% reduced the benzene conversion from 28 to 4%. However, other SPG components had insignificant impacts on benzene conversion.

Volatile-char interactions during biomass pyrolysis: Insight into the activity of chars derived from three major components

Char activity is a critical factor for the interactions between char and volatile, which are recognized to determine the final product distribution from biomass pyrolysis. To clarify the effect of biomass composition on char activity, the interactions between (benzyloxy)benzene as a volatile model compound and char samples obtained from cellulose, xylan, and lignin were studied. The (benzyloxy)benzene conversion increased from 0.64 % for no char to 6.31 %, 6.98 % and 53.5 % for lignin char, cellulose char, and xylan char, respectively, which were mainly derived from the contribution of surface CO groups and surface defects in the carbon structure. Especially, surface C(sp2)O groups and C(sp3)O groups on char respectively favored the breakage of C(sp3)O and C(sp2)O bonds in (benzyloxy)benzene. Despite the low activity, lignin char showed high selectivity to monomeric products due to the high content of surface CO groups, which were considered to induce the production of hydrogen radicals to stabilize the resulting intermediates. The findings of this study prove that the volatile-char interaction could be adjusted facilely by changing the hemicellulose content during feedstock pretreatments.

Nanotubular OMS-2 Supported Single-Atom Platinum Catalysts Highly Active for Benzene Oxidation

The cryptomelane-type octahedral molecular sieve (OMS-2) exhibits excellent catalytic activity for the oxidation of volatile organic compounds (VOCs) due to its unique structure, and single-atom catalysts (SACs) have recently attracted much attention in heterogeneous catalysis. Herein, we adopted the hydrothermal redox reaction of KMnO4 and HCl aqueous solution at 120 °C for 12 h to first synthesize the nanotubular OMS-2 support and used the vitamin C and NaBH4 reduction methods to prepare the OMS-2-supported single-atom Pt and PtNP catalysts for benzene oxidation, respectively. It was found that the OMS-2-supported single-atom Pt catalyst with a Pt loading of 0.0383 wt % (0.0383Pt1/OMS-2) exhibited the best catalytic performance for benzene oxidation (a 90% benzene conversion was achieved at 189 °C and 20 000 mL g–1 h–1 (space velocity)), which was associated with its high surface oxygen vacancy density, good low-temperature reducibility, and strong benzene adsorption ability. It was also shown that benzene could be dissociated more readily over the supported single-atom Pt1 catalyst than over the supported PtNP catalyst, and the phenolates or benzoquinone as well as methyl groups, lipid, and vinyl species were the main intermediates in the oxidation of benzene over 0.0383Pt1/OMS-2. The results of this study are useful in developing the high-performance single-atom catalysts that can be applied for the oxidative removal of VOCs.

Synthesis TS-1 nanozelites via L-lysine assisted route for hydroxylation of Benzene

L-lysine is used as a crystallization regulator, and a two-step synthesis method is adopted in a concentrated gel system, which provides a new route to synthesize of nano-sized TS-1 zeolite. The new synthesis strategy was used to successfully synthesize TS-1 zeolite with a particle size less than 100 nm. The rate of crystal nucleation is faster than the crystal growth at the low temperature in the first step. Introduction of L-lysine can prevent crystal growth to form nano-sized TS-1 zeolite at the high temperature in the second step. Meanwhile, L-lysine decrease the pH value of the gel system, which is favorable for Ti atoms to incorporate the TS-1 framework. TS-1 nanozeolite can effectively reduce the diffusion resistance, and nanozeolite has a large specific surface area and high stability. Therefore, TS-1 nanozeolite exhibits the excellent catalytic performance during the hydroxylation of benzene. The conversion of benzene has been greatly improved and the types of by-products are effectively reduced. The conversion of benzene reached 50.2%, and the yield of phenol was 30.8% without by-product benzoquinone. TS-1 nano-zeolite as a catalyst for benzene hydroxylation shows great potential in industrial application.