Transformation Of Toluene Research Articles

Insights into catalytic oxidation mechanism of toluene by lanthanum mangan-based perovskite in wet environment based on in-situ DRIFTS

This paper investigated that the catalytic activity and CO2 selectivity of LaMnO3, La0.9Ca0.1MnO3 and 3-La0.9Ca0.1MnO3 catalysts with different oxygen vacancy concentrations were compared under wet and dry conditions. The 3-La0.9Ca0.1MnO3 catalysts had excellent water resistance. The presence of H2O had less effect on toluene conversion than on CO2 selectivity. In wet environment, the 3-La0.9Ca0.1MnO3 catalyst achieved 90 % toluene conversion at 173 °C, but less than 20 % selectivity for CO2 at this time, and reached 90 % selectivity for CO2 at 220 °C. The effect of H2O on the catalytic oxidation mechanism of toluene was analyzed by in-situ DRIFTS analysis. The presence of H2O could promote the decomposition of toluene into intermediates of benzyl alcohol, benzoic acid, benzaldehyde and maleic anhydride at low temperature (50 °C), but the intermediates were difficult to decompose into CO2 and H2O. It was suggested that surface hydroxyl group could promote the transformation of toluene to intermediate at low temperature, and suitable oxygen vacancies and surface hydroxyl group could jointly promote the transformation of toluene to ideal product. This work provided a theoretical basis for the design of water-resistant catalysts in industry.

A Conceptual Model for Depicting the Relationships between Toluene Degradation and Fe(III) Reduction with Different Fe(III) Phases as Terminal Electron Acceptors

Iron reduction is one of the most crucial biogeochemical processes in groundwater for organic contaminants biodegradation, especially in the iron-rich aquifers. Previous research has posited that the reduction of iron and the biodegradation of organic substances occur synchronously, with their processes adhering to specific quantitative relationships. However, discrepancies between the observed values of iron reduction and organic compound degradation during the reaction and their theoretical counterparts have been noted. To find out the relationship between organic substance biodegradation and iron reduction, this study conducted batch experiments utilizing toluene as a typical organic compound and electron donor, with various iron minerals serving as electron acceptors. Results indicate that toluene degradation follows first-order kinetic equations with different degradation rate constants under different iron minerals, but the generation of the iron reduction product Fe(II) was not uniform. Based on these dynamic relationships, a conceptual model was developed, which categorizes the reactions into two phases: the transformation of toluene to an intermediate-state dominated phase and the mineralization of the intermediate-state dominated phase. This model revealed the relationships between toluene oxidation and Fe(II) formation in the toluene biodegradation through iron reduction. The coupling mechanism of toluene degradation and iron reduction was revealed, which is expected to improve our ability to accurately assess the attenuation of organic contaminants in groundwater.

Solar-driven photocatalytic transformation of toluene to benzoic acid over perovskite-type NiTiO3 decorated with reduced GO and g-C3N4 nanosheets

In this work, a perovskite-type nickel (II) titanate (NiTiO3; labeled as NTO) was synthesized and supported with reduced graphene oxide (rGO) and graphitic carbon nitride (CN: g-C3N4) nanosheets by ultrasound-assisted impregnation method. The solar-induced photocatalytic activity and selectivity of the prepared NTO-based perovskite catalysts were evaluated for toluene (TOL) oxidation to benzoic acid (B_COOH) under varying operating conditions. Results revealed that the NTO perovskite exhibited a higher selectivity (95–98%) for the photooxidation of TOL to B_COOH by 125–95 times higher than benzaldehyde (B_CHO) and benzyl alcohol (B_CH2OH) at 1 vol% H2O2 and O2 flow. At zero H2O2 level, the selective oxidation of TOL to B_CHO and B_CH2OH enhanced by 5.4 and 2.7 times as compared with the B_COOH production rate. Besides, NTO@CN (NTN) outperformed NTO@rGO (NTG) for the selective photocatalytic oxidation of TOL to B_COOH in solvent-free and water media under UV, visible, and sunlight irradiation. The production yield of B_COOH was 388.4, 491.2, and 455.6 µmol/L over NTO, NTN, and NTG, respectively at 1 vol% H2O2 and O2 flow for 3 h of solar irradiation. In both composites, carbon sheets supported the photocatalytic stability of NTO and potential energy for H2O2 decomposition to ∙OH radicals. This is validated by the radical scavenger test and electron paramagnetic resonance (EPR) analysis, which verified the crucial role of hydroxyl (•OH) radicals in the photocatalytic oxidation of TOL to B_COOH. These findings proved the effectiveness of NTN and NTG perovskite composites for solar-induced organic synthesis of benzoic acid from water contaminated with toluene using sunlight (as a renewable energy source).

Nickel Nanoparticles for Liquid Phase Toluene Oxidation – Phenomenon, Opportunities and Challenges

AbstractEffective oxidative transformation of toluene into valuable products was achieved under solvent‐free reaction conditions with as‐prepared nickel nanoparticles as heterogeneous catalysts in liquid phase. The crystalline structure and size of the as‐prepared nanoparticles were confirmed by X‐ray diffractometry (XRD) and dynamic light scattering (DLS). The catalytic implications of the different crystalline forms (face‐centred cubic: fcc; hexagonal close‐packed: hcp) of these nanocatalysts were investigated. The product selectivity of toluene oxidation was found to vary depending on the crystalline forms of the catalyst. Fcc nanocatalysts showed remarkable chemoselectivity (83 mol %) for the product benzyl alcohol and were readily reusable. In contrast, the hcp Ni phase showed reasonable reusability but lower chemoselectivity (29 mol %) compared to its fcc counterpart. Moreover, the simple organic solvents used had a remarkable effect on the crystal structure and phase purity of the Ni nanocrystals, which also affected the catalytic process.

The journey of toluene to complete mineralization via heat-activated peroxydisulfate in water: intermediates analyses, CO2 monitoring, and carbon mass balance

Our study has thoroughly investigated the complete mineralization of toluene in water via heat-activated peroxydisulfate (PDS) by: (1) monitoring concentrations/peak areas of various intermediates and CO2 throughout the reaction period and (2) identifying water-soluble and methanol-soluble intermediates, including trimers, dimers, and organo-sulfur compounds, via non-target screening using high-resolution mass spectrometry. Increased temperature and PDS dosage enhanced toluene removal/mineralization kinetics and increased the rate/extent of benzaldehyde formation and its further transformation. Artificial groundwater and phosphate buffer minimally impacted toluene removal but significantly decreased benzaldehyde formation, indicating a shift in transformation pathways. The stoichiometric PDS dose (18 mM at 40 °C) was adequate to completely mineralize toluene (1 mM), with < 10% PDS needed to transform toluene to intermediates. Toluene transformation to intermediates occurred in 47 h (kobs,toluene = 0.594 h-1) whereas 564 h were required for complete mineralization (kobs,CO2 = 0.0038 h-1). O2 accumulated once mineralization neared completion. A carbon mass balance, including quantification of nine intermediates and CO2 throughout the transformation period, showed that unquantified/unknown intermediates (including yellowish-white precipitates) reached as high as 80% of total carbon before transformation to CO2. Possible toluene transformation pathways via hydroxylation, sulfate addition, and oxidative coupling are proposed.

Toluene methylation with syngas to para-xylene by bifunctional ZnZrOx-HZSM-5 catalysts

Toluene methylation with methanol on H-ZSM-5 (Z5) zeolite for the directional transformation of toluene to xylene has been industrialized. However, great challenges remain because of the high energy barrier of methanol deprotonation to the methoxy group, the side reaction of methanol to olefins, coke formation, and the deactivation of zeolites. Herein, we report the toluene methylation coupled with CO hydrogenation to showcase an enhancement in para-xylene (PX) selectivity by employing a bifunctional catalyst composed of ZnZrOx (ZZO) and modified Z5. The results showed that a PX selectivity of up to 81.8% in xylene and xylene selectivity of 64.8% in hydrocarbons at 10.3% toluene conversion can be realized over the bifunctional catalyst on a fixed-bed reactor. The selectivity of gaseous hydrocarbons decreased to 10.9%, and approximately half of that was observed in methanol reagent route where the PX selectivity in xylene was 38.8%. We observed that the acid strength, the quantity ratio of Brönsted and Lewis acid sites, and the pore size of zeolites were essential for the PX selectivity. The investigation of the H2/D2 kinetic isotope effect revealed that the newborn methyl group in xylene resulted from the hydrogenation of CO rather than toluene disproportionation. Furthermore, the catalyst showed no evident deactivation within the 100 h stability test. The findings offer a promising route for the production of value-added PX with high selectivity via toluene methylation coupled with syngas conversion.

Long-term degradation of toluene and phenol in soil: Identification of transformation products and pathways via HRMS-based suspect and non-target screening

In this study, the long-term fate of toluene and phenol in the soil was investigated, and the transformation products (TPs) and pathways of these compounds were studied by a high resolution mass spectrometry (HRMS)-based suspect and non-target screening approach for the first time, and 9 and 12 transformation products were identified for toluene and phenol, respectively in the lab-exposed soil samples. Salicylaldehyde, 4-hydroxybenzaldehyde, and benzaldehyde were identified in toluene-contaminated field soil samples for the first time, and the main mechanisms involved in the biodegradation and detoxification of toluene and phenol in soil were oxidation, carboxylation, dehydroxylation, and ring fission amongst others. 2-oxoglutarate, TP165-A, TP165-B, TP172, and TP195 were identified as novel phenol transformation products, while salicylaldehyde, 2-oxoglutarate, TP165-A, and TP165-B were identified as novel toluene transformation products, providing new possible evidence for additional degradation pathways, which could give new insights into the fate of toluene and phenol during the natural attenuation process in the environment. Finally, salicylaldehyde, 4-OH-benzaldehyde, and 4-OH-benzoic acid which were detected at Level 1 identification confidence were suggested as indicator chemicals of toluene and phenol exposure in the contaminated field.

Solar-Driven Photocatalytic Transformation of Toluene to Benzoic Acid Over Perovskite-Type NiTiO3 Decorated with Reduced GO and g-C3N4 Nanosheets

Solar-Driven Photocatalytic Transformation of Toluene to Benzoic Acid Over Perovskite-Type NiTiO3 Decorated with Reduced GO and g-C3N4 Nanosheets

PH-Controlled assembly of [ZnW12O40]6--based hybrids from a 0D dimer to a 2D network: synthesis, crystal structure, and photocatalytic performance in transformation of toluene into benzaldehyde.

Polyoxometalate-based organic-inorganic hybrids have attracted considerable attention due to their fascinating structures and wide application prospects. In this work, using the same building blocks, ligands and metal ions (ZnW12O406-(ZnW12), 2,2'-bipyridine (2,2'-bipy), and Cu2+), we synthesized three new POM-based hybrids by controlling the pH values of the reaction systems. These three compounds {(Zn0.6(H2)0.4W12O40)[Cu(2,2'-bipy)(H2O)][Cu(2,2'-bipy)(H2O)2][Cu(2,2'-bipy)(H2O)3]}2·6H2O (1), (Me4N)2{ZnW12O40[Cu(2,2'-bipy)(H2O)][Cu(2,2'-bipy)(H2O)3]}·5H2O (2), and {(Zn0.5(H2)0.5W12O40)[Cu(2,2'-bipy)][Cu(2,2'-bipy)(H2O)][Cu(2,2'-bipy)(H2O)2]}·5H2O (3) have been structurally characterized by single-crystal X-ray diffraction. Compound 1 appears as a dimeric cluster structure, while compounds 2 and 3 appear as a 1D chain structure and a 2D network, respectively. The semiconducting properties of compounds 1-3 are different, which was demonstrated by band gap (Eg) and photocurrent response measurements. Compound 3 can efficiently catalyze the photooxidation of toluene to benzaldehyde with high selectivity using molecular oxygen as the oxidant component. Moreover, compound 3 was recycled and reused three times without significant degradation in conversion and selectivity. In addition, the mechanism of the photocatalytic reaction was also investigated.

Fluoride etching of AlZSM-5 and GaZSM-5 zeolites

The post-synthesis treatment of AlZSM-5 and GaZSM-5 zeolites by etching with buffer solution of ammonium fluoride and 0.25 M HF acid was carried out. The treatment is applied in order to obtain secondary pores in crystals and to provide easier access to the catalytically active zeolite centers. Hydrothermal synthesis of these zeolites was performed from systems containing tetrapropylammonium bromide as a template. The reaction parameters of synthesis conditions for both zeolites were optimized in order to obtain pure crystalline phases. The zeolites obtained were characterized by X-ray diffraction, IR spectroscopy, scanning electron microscopy, physical adsorption–desorption of nitrogen and solid-state NMR spectroscopy. It has been found that the result materials remain with high crystallinity while new mesoporous are created in their structure. The volume due to the presence of mesopores increases by up to 67% from the total volume, which is a drastic increase compared with the parent solids. The investigations with FTIR spectroscopy of low-temperature CO adsorption and solid-state NMR spectroscopy show that the treatment is slightly selective toward dissolution of heteroatom (aluminum or gallium). This phenomenon is observed for the first time for gallium-substituted zeolites. In order to study the influence of the metal atom in zeolite structure and the efficacy of the acid attack on the catalytic activity, the samples obtained were tested in reaction of m-xylene and toluene transformation.

The high selectivity for benzoic acid formation on Ca2Sb2O7 enables efficient and stable toluene mineralization

The selectivity for different intermediates in VOCs degradation process may lead to different reaction paths, which determines the overall pollutant degradation efficiency. In this work, Ca2Sb2O7 shows a superior photocatalytic activity and stability in gaseous toluene degradation as compared to P25. To shed light on the mechanism of efficient and stable toluene degradation, particularly the role of selectivity for intermediates during the reaction process, the theoretical and experimental approaches were closely combined. Owing to the promoted charge transfer between the absorbents (such as O2, H2O, toluene and other intermediates) and Ca2Sb2O7, both the ROS generation and principal intermediates adsorption are significantly enhanced, which leads to a high selectivity for benzoic acid formation. That is confirmed by in suit DRIFTS and theoretical calculations. Enhanced generation of benzoic acid on Ca2Sb2O7 surface could improve the efficiency of toluene ring-opening and over-all degradation due to lower energy barrier for toluene transformation into benzoic acid. Thus, this could enable efficient and stable degradation of toluene and prevent the catalyst from deactivation. This work provides new insight into the mechanistic understanding of photocatalytic VOCs degradation reaction.

Toluene oxidation over Co3+-rich spinel Co3O4: Evaluation of chemical and by-product species identified by in situ DRIFTS combined with PTR-TOF-MS

Series of Co3+-rich spinel Co3O4 catalysts were synthesized and evaluated by toluene catalytic oxidation. An outstanding activity was achieved over Co3O4-N utilizing Co(NO3)2·6H2O as precursor (T50 = 211 °C, T90 = 217 °C at conditions: 1000 ppm(v), WHSV = 60 000 mL g−1 h−1). Results of comparative characterizations demonstrated that such excellent performance was mainly attributed to large surface area, high reducibility at low temperature, high abundance of Co3+ ions and structure defects, as well as highly active surface oxygen. The results of in situ DRIFTS revealed that in the air or N2 atmosphere, the by-products were almost the same. The reaction pathway of toluene oxidation can be described as follow: transformation of toluene from benzyl alcohol, benzaldehyde, benzoate, benzene, phenol, benzoquinone, maleic acid and to final products, which were fully confirmed by PTR-TOF-MS. Besides, ring opened by-products, such as acetone, acetic acid, acetaldehyde, etc. were also detected. In this work, the combination of in situ DRIFTS and PTR-TOF-MS provided a promising approach for further understanding of the mechanism of VOCs elimination.

Toluene degradation via a unique metabolic route in indigenous bacterial species.

Tanneries are the primary source of toluene pollution in the environment and toluene due to its hazardous effects has been categorized as persistent organic pollutant. Present study was initiated to trace out metabolic fingerprints of three toluene-degrading bacteria isolated from tannery effluents of Southern Punjab. Using selective enrichment and serial dilution methods followed by biochemical, molecular and antibiotic resistance analysis, isolated bacteria were subjected to metabolomics analysis. GC-MS/LC-MS analysis of bacterial metabolites helped to identify toluene transformation products and underlying pathways. Three toluene-metabolizing bacteria identified as Bacillus paralicheniformis strain KJ-16 (IUBT4 and IUBT24) and Brevibacillus agri strain NBRC 15538 (IUBT19) were found tolerant to toluene and capable of degrading toluene. Toluene-degrading potential of these isolates was detected to be IUBT4 (10.35 ± 0.084mg/h), IUBT19 (14.07 ± 3.14mg/h) and IUBT24 (11.1 ± 0.282mg/h). Results of GC-MS analysis revealed that biotransformation of toluene is accomplished not only through known metabolic routes such as toluene 3-monooxygenase (T3MO), toluene 2-monooxygenase (T2MO), toluene 4-monooxygenase (T4MO), toluene methyl monooxygenase (TOL), toluene dioxygenase (Tod), meta- and ortho-ring fission pathways. But additionally, confirmed existence of a unique metabolic pathway that involved conversion of toluene into intermediates such as cyclohexene, cyclohexane, cyclohexanone and cyclohexanol. LC-MS analysis indicated the presence of fatty acid amides, stigmine, emmotin A and 2, 2-dinitropropanol in supernatants of bacterial cultures. As the isolated bacteria transformed toluene into relatively less toxic molecules and thus can be preferably exploited for the eco-friendly remediation of toluene.

Cyclometalated Iridium(III) Complexes Containing Benzoxazole Derivatives and Different Ancillary Ligands for Catalytic Oxidation of Toluene

A series of cyclometalated iridium(III) complexes that have the general formula [(C^N)2Ir(NR)(X)] (C^N = monoanionic bidentate cyclometalating ligands; NR = pyridine derivatives; X = Cl− or I−) are designed, prepared, and applied for the transformation of toluene to benzaldehyde using a clean, highly efficient, and environmentally-friendly process. The activation energies that are needed for the catalytic oxidation of toluene when using these complexes as catalysts are quite low: between 22.9 and 30.8 kcal mol−1. The catalytic frequencies (TOF) are fairly high (up to 7.0 × 102 h−1) with excellent reliability, and the turnover number (TON) can reach 4.2 × 103 after 6 h of processing time. Catalytic tests, X-ray absorption near-edge structure (XANES), and kinetic modeling are used to derive detailed insights into the characteristics of the catalysts and their effects on the reactions that are featured in the catalytic oxidation of toluene.

Insights into the role of humic acid on Pd-catalytic electro-Fenton transformation of toluene in groundwater.

A recently developed Pd-based electro-Fenton (E-Fenton) process enables efficient in situ remediation of organic contaminants in groundwater. In the process, H2O2, Fe(II), and acidic conditions (~pH 3) are produced in situ to facilitate the decontamination, but the role of ubiquitous natural organic matters (NOM) remain unclear. This study investigated the effect of Aldrich humic acid (HA) on the transformation of toluene by the Pd-based E-Fenton process. At pH 3 with 50 mA current, the presence of HA promoted the efficiency of toluene transformation, with pseudo-first-order rate constants increase from 0.01 to 0.016 as the HA concentration increases from 0 to 20 mg/L. The HA-enhanced toluene transformation was attributed to the accelerated thermal reduction of Fe(III) to Fe(II), which led to production of more hydroxyl radicals. The correlation of the rate constants of toluene transformation and HA decomposition validated hydroxyl radical (·OH) as the predominant reactive species for HA decomposition. The finding of this study highlighted that application of the novel Pd-based E-Fenton process in groundwater remediation may not be concerned by the fouling from humic substances.

Highly selective formation of benzene upon toluene transformation on CsY zeolite

Gas-phase transformation of toluene is carried out on Cs-exchanged NaY zeolite in a fixed-bed tubular reactor and it is observed that toluene can transform through dealkylation, producing benzene and a small amount of hydrogen under the experimental conditions. After a definite activation period, the transformation of toluene can achieve its steady state with the yield of benzene above 25 % for a relatively long continuous time at low space velocity. Combining the results of characterization and catalytic performances, it can be concluded that benzene is the steadiest product except the carbonaceous residues within the CsY zeolite pores. The in situ carbonaceous deposition experiment shows a similar trend of the carbonaceous forming process and the yield of benzene, indicating the important role of carbonaceous species in the formation of benzene, i.e., it is necessary for the accumulation of carbonaceous species in the initial stage of reaction. The discovery in the current work sheds light on new strategies for the transformation of other similar compounds.

Isotopic Analysis of Oxidative Pollutant Degradation Pathways Exhibiting Large H Isotope Fractionation

Oxidation of aromatic rings and its alkyl substituents are often competing initial steps of organic pollutant transformation. The use of compound-specific isotope analysis (CSIA) to distinguish between these two pathways quantitatively, however, can be hampered by large H isotope fractionation that precludes calculation of apparent (2)H-kinetic isotope effects (KIE) as well as the process identification in multi-element isotope fractionation analysis. Here, we investigated the C and H isotope fractionation associated with the transformation of toluene, nitrobenzene, and four substituted nitrotoluenes by permanganate, MnO4(-), to propose a refined evaluation procedure for the quantitative distinction of CH3-group oxidation and dioxygenation. On the basis of batch experiments, an isotopomer-specific kinetic model, and density functional theory (DFT) calculations, we successfully derived the large apparent (2)H-KIE of 4.033 ± 0.20 for the CH3-group oxidation of toluene from H isotope fractionation exceeding >1300‰ as well as the corresponding (13)C-KIE (1.0324 ± 0.0011). Experiment and theory also agreed well for the dioxygenation of nitrobenzene, which was associated with (2)H- and (13)C-KIEs of 0.9410 ± 0.0030 (0.9228 obtained by DFT) and 1.0289 ± 0.0003 (1.025). Consistent branching ratios for the competing CH3-group oxidation and dioxygenation of nitrotoluenes by MnO4(-) were obtained from the combined modeling of concentration as well as C and H isotope signature trends. Our approach offers improved estimates for the identification of contaminant microbial and abiotic oxidation pathways by CSIA.

Fenton-like initiation of a toluene transformation mechanism

In Fenton-driven oxidation treatment systems, reaction intermediates derived from parent compounds can play a significant role in the overall treatment process. Fenton-like reactions in the presence of toluene or benzene, involved a transformation mechanism that was highly efficient relative to the conventional Fenton-driven mechanism. A delay in hydrogen peroxide (H 2O 2) reaction occurred until the complete or near-complete transformation of toluene or benzene and involved the simultaneous reaction of dissolved oxygen. This highly efficient transformation mechanism is initiated by Fenton-like reactions, and therefore dependent on conventional Fenton-like parameters. Results indicated that several potential parameters and mechanisms did not play a significant role in the transformation mechanism including electron shuttles, Fe chelates, high valent oxo-iron complexes, anionic interferences in H 2O 2 reaction, and H 2O 2 formation. The Fenton-like initiation, formation, and propagation of a reaction intermediate species capable of transforming toluene, while simultaneously inhibiting H 2O 2 reaction is the most viable mechanism.

Transformation of Toluene and 1,2,4-Trimethylbenzene over ZSM-5 and Mordenite Catalysts: A Comprehensive Kinetic Model with Reversibility

The catalytic transformations of toluene, 1,2,4-trimethylbenzene (TMB), and an equimolar mixture of the two compounds were investigated over H-mordenite and H-ZSM-5 catalysts. A series of experiments were conducted in a riser simulator over a temperature range of 300−400 °C and reaction times of 5−20 s. The influence of reaction conditions on variation of 1,2,4-TMB conversion, toluene conversion, para- to ortho-xylene ratio, xylenes to TMB isomers ratio, 1,3,5-TMB to 1,2,3-TMB ratio, and xylenes to benzene ratio were discussed. The study also includes the development of comprehensive kinetic models for isomerization, disproportionation, and transalkylation reactions of 1,2,4-TMB and toluene. The models account for reversibility of the isomerization reaction based on values of temperature dependent thermodynamic equilibrium constants. Catalysts deactivation was modeled using an activity decay function based on time-on-stream (TOS). The developed models gave a good match with experimental data based on a st...

The transformations of toluene on alumina and bifunctional catalysts

The activity of Pt, Rh, and Ni catalysts deposited on Al2O3 and tungsten-containing catalysts 20% H4SiW12O40/ZrO2 and 15% WOx/ZrO2 in the hydrogenation of toluene and toluene ring opening and isomerization in the presence of hydrogen was studied. Under experimental conditions (160–360°C, 2.2 MPa), the main reactions on Rh/Al2O3 were the hydrogenation of toluene into methylcyclohexane, hydrogenolysis into isoheptanes, and hydrocracking into alkanes C1–C6. On Pt, Rh, and Ni catalysts on carriers with strong acid properties, the isomerization of the six-membered into five-membered ring followed by hydrogenolysis (hydrocracking) of alkylcyclopentanes occurred. The yield of heptane isomers, however, did not exceed 13%. The activity of Pt and Rh catalysts on a high-acidity carrier (WOx/ZrO2) in hydrocracking was much higher than that of catalysts based on deposited heteropoly acid. The yields of hydrogenolysis (hydrocracking) products on Ni/WOx/ZrO2 were much lower than on Pt(Rh)/WOx/ZrO2. The highest yield of ring opening products (isoheptanes and n-heptane) was obtained with layered loading of two catalysts; it reached 58 wt % at 300°C and a 2.2 MPa pressure, which was 4.5 and 2 times higher than the yield obtained on Ni-Pt/WOx/ZrO2 and 2% Rh/Al2O3 catalysts. Hydrodemethylation was not the main direction of toluene transformations on any of the catalysts studied.