Al2O3 Ratio Research Articles

Conversion of coal gangue into alumina, tobermorite and TiO2-rich material

A large amount of coal gangue from coal mining and processing is regarded as waste and usually stockpiled directly. In order to recycle the valuable elements from the coal gangue, an integrated process is proposed. The process consists of three steps: 1) concentrating alumina from the coal gangue via activation roasting followed by alkali leaching of SiO2 which produces alumina concentrate for alumina extraction by the Bayer process; 2) synthesizing tobermorite whiskers from the filtrated alkali liquor containing silicate via a hydrothermal method and reusing excess caustic liquor; and 3) enriching titanium component from the Bayer process residue by sulfuric acid leaching. Alumina concentrate with 69.5% Al2O3 and mass ratio of alumina to silica (A/S) of 5.9, pure 1.1 nm tobermorite whisker and TiO2-rich material containing 33% TiO2 are produced, respectively, with the optimal parameters. Besides, the actual alumina digestion ratio of alumina concentrate reaches 80.4% at 270 oC for 40 min in the Bayer process.

Viscosity and Structure Changes of CaO-SiO2-Al2O3-CaF2 Melts with Substituting Al2O3 for SiO2

During the smelting process of the high Al steels, the reaction between SiO2 in molten slag and dissolved aluminum in liquid steel always takes place. This aluminathermic reduction reaction will lead to the substitution of 1 mol SiO2 for 2/3 mol Al2O3. Therefore, the investigations about the influence of the ratio of Al2O3 to SiO2 on viscosity and structure changes of mould flux during this process are very necessary. The viscosity variation of CaO-SiO2-Al2O3-CaF2 melts was studied by changing compositions considering the aluminathermic reduction reaction. It was found that viscosity increased monotonously with gradually increasing the substitution extent. According to the Raman analysis, the substitution of Al2O3 for SiO2 leads to the decrease of non-bridging oxygen but the increase of bridging oxygen. Therefore, degree of polymerization and viscosity increase as the substitution extent increases. By comparing the measured viscosities with the model calculated values, it was found that both the recently developed Zhang's model and Roboud model could describe the viscosity variation behavior of CaO-SiO2-Al2O3-CaF2 melts very well.

EU-12: A Small-Pore, High-Silica Zeolite Containing Sinusoidal Eight-Ring Channels.

Zeolite EU-12, the framework structure of which has remained unsolved during the past 30 years, is synthesized at a specific SiO2 /Al2 O3 ratio using choline as an organic structure-directing agent, with both Na(+) and Rb(+) ions present. Synchrotron powder X-ray diffraction and Rietveld analyses reveal that the EU-12 structure has a two-dimensional 8-ring channel system. Among the two distinct 8-ring (4.6×2.8 and 5.0×2.7 Å) channels along c axis, the smaller one interconnects with the sinusoidal 8-ring (4.8×3.3 Å) channel along a axis. The other large one is simply linked up with the sinusoidal channel by sharing 8-rings (4.8×2.6 Å) in the ac plane. The proton form of EU-12 was found to show a considerably higher ethene selectivity in the low-temperature dehydration of ethanol than H-mordenite, the best catalyst for this reaction.

Effect of mechanical properties on the ballistic resistance capability of Al2O3-ZrO2 functionally graded materials

Because Al2O3 exhibits high strength and hardness, it is prevalently used as a ceramic material. ZrO2 is often added to increase the toughness of such a material. Therefore, this study mixed Al2O3 and ZrO2 to formulate functionally graded materials (FGMs). four-layer and eleven-layer Al2O3-ZrO2 FGMS were produced from Al2O3 and ZrO2 mixtures by sintering at 1500°C. Moreover, testing sheets were created by mixing various ratios of Al2O3 and ZrO2 to analyze their fracture toughness and hardness. The results revealed the 90% Al2O3-10% ZrO2 sheet to exhibit a hardness of 15.12GPa, and the 50% Al2O3-50% ZrO2 sheet to attain a fracture toughness as high as 4.7MPam0.5. The impact resistance test involved analyzing various types of testing sheets, including the four-layer Al2O3-(0%, 10%, 20%, 30%) ZrO2 FGM, eleven-layer Al2O3-(0–100%) ZrO2 FGM, 100% Al2O3 composite material, 90% Al2O3-10% ZrO2 composite material, 70% Al2O3-30% ZrO2 composite material, and 50% Al2O3-50% ZrO2 composite material. The ballistic tests showed that FGMs of the same areal density (4.64g/cm2) or thickness (11mm) attained the highest energy absorption. The experimental results confirmed that FGMs can delay the formation and propagation of ceramic cones. Specifically, toughened alumina materials prevent the growth of radial and circumferential cracks, delay the formation of ceramic cones, decrease cones hitting against the back plane, and increase the penetrating resistant capability of the ceramic materials experiencing bullet impact, features important for applications in fields such as aerospace, aviation, automobile, the military industry, and biomedicine

Two episodes of partial melting in ultrahigh-pressure migmatites from deeply subducted continental crust in the Sulu orogen, China

Partial melting plays an important role in the geodynamics of continental subduction zones. This is identified from a suite of ultrahigh-pressure (UHP) migmatites in the Sulu orogen through a combined study of zircon U-Pb ages, trace elements, and oxygen isotopes, as well as rock-forming mineral and inclusion compositions. The results indicate two episodes of partial melting in the subducted continental crust during continental collision, providing insights into subduction channel processes. The first episode of anatexis is indicated by the occurrence of nanogranites, not only in zircon, garnet, and monazite from diatexite, but also in zircon cores from leucosome. The anatectic zircon exhibits U-Pb ages of 230−227 Ma and flat rare earth element (REE) patterns with weak or no negative Eu anomalies, and it contains mineral inclusions of coesite and garnet + amphibole. Newly grown zircon grains in the diatexite and zircon cores in the leucosome exhibit high δ 18 O values of 8.3‰−17.3‰, indicating a metasedimentary protolith. The host rocks show high A/CNK (= molar ratio of Al 2 O 3 /[CaO + Na 2 O + K 2 O]) values and the occurrence of peritectic garnet in the diatexite. Thus, the diatexite was produced by partial melting of metasedimentary rocks. The Ti-in-zircon thermometry, the garnet-phengite Fe-Mg partition thermometry for mineral inclusions in the zircon, and the occurrence of coesite inclusions in zircon indicate partial melting at 650−800 °C and 2.5−3.0 GPa, corresponding to high-pressure (HP) to UHP conditions. On the other hand, the second episode of anatexis is recorded by newly grown zircon grains in metatexite and zircon rims in leucosome, which show U-Pb ages of 218−214 Ma, oscillatory zoning, steep heavy (H) REE patterns with negative Eu anomalies, low temperatures of 550−700 °C, and significant variations in Th, U, Nb, and Ta contents. The Zr-in-titanite thermometry for nanogranite-bearing titanite and the garnet-phengite Fe-Mg partition thermometry for mineral inclusions in the leucosome zircon rims indicate anatexis at 800−850 °C and 1.0−1.5 GPa. The zircon in the metatexite exhibits low δ 18 O values of −1.5‰−3.5‰ and Neoproterozoic U-Pb ages for relict magmatic cores, indicating the protolith of a low δ 18 O UHP metagranite. The two episodes of anatexis yield zircon domains with a series of differences not only in U-Pb age, but also in geochemical composition. Thus, protoliths with different origins were involved in the anatexis, with a possible difference in spatial positions. The UHP metasedimentary rocks atop the deeply subducted continental crust would have undergone the first episode of anatexis during the final subduction, whereas their underlying metagranite would have undergone the second episode of anatexis during the exhumation of deeply subducted crust. In either case, the breakdown of UHP hydrous minerals during exhumation is the key for the partial melting of UHP metamorphic rocks in the continental subduction channel.

Coordination state of aluminum and boron in barium aluminoborate glass

This paper considers the coordination state of boron and aluminum ions in barium aluminoborate glass with a constant ratio of BaO: B2O3 = 0.5 and a variable ratio of Al2O3: BaO = 0–3. The dependence of the concentrations of boron and aluminum atoms with a variable coordination number on the Al2O3 content was estimated by IR, 11B and 27Al NMR spectroscopy. The nonlinear nature of the obtained dependences was attributed to variations in the aluminum oxide properties. At a content of less than 30 mol % Al2O3 serves primarily as a network former, while an increase in the Al2O3 concentration results in its higher modifying role in the studied glass.

Investigation and Optimization of Use of Anionic Collectors in Direct Flotation of Bauxite Ores

Bauxite is the main raw material for the alumina industry. Direct flotation is the most widely used method for bauxite beneficiation. In this study, a large number of direct flotation tests were carried out using several anionic reagents. The testing concluded that vegetable oil acid (VOA), naphthenic acid (NA) and lauryl polyoxyethylene phosphate (AEP12) were the three outstanding collectors for bauxite direct flotation. ZMC collector was mixed and prepared using VOA, NA and AEP12, in which the mass ratio of VOA, NA and AEP12 was 1:1:0.5. When processing the bauxite ores of the mass ratio of Al2O3 to SiO2 (A/S) = 4.99, the A/S of the final concentrate was 7.08 and the recovery of Al2O3 was 90.22%. When processing ores of A/S = 4.5, the A/S of the final concentrate was 7.04 and the recovery of Al2O3 was 92.16%. Thus, it can be seen that properties and behaviors of the ZMC reagent were remarkable and met the demands of the Lime-Bayer Process.

Comparison of mathematical and artificial neural network models for inhibition of fuel oil ash under high temperature corrosion

This research reports the results of literature data of mass loss tests of high temperature corrosion inhibition of steel in different concentration ratios of MgO, Al2O3 and SiO2 to corrosive fuel ash of V2O5 in the temperature range of 550–590°C and time range of 8–100 h. Analysis focused on determining optimum mathematical equation and artificial neural network (ANN) architecture in order to gain good prediction properties. Three mathematical equations and five ANN architectures were suggested. A computer aided program was used for developing these models. Results show that polynomial mathematical equation and multilayer perceptron are able to accurately predict selected data with high correlation coefficients.

Flotation of low-grade bauxite using organosilicon cationic collector and starch depressant

The flotation of diaspore and three kinds of silicate minerals, including kaolinite, illite and pyrophyllite, using an organosilicon cationic surfactant (TAS101) as collector and starch as depressant was investigated. The results show that both diaspore and aluminosilicate minerals float readily with organosilicon cationic collector TAS101 at pH values of 4 to 10. Starch has a strong depression effect for diaspore in the alkaline pH region but has little influence on the flotation of aluminosilicate minerals. It is possible to separate diaspore from aluminosilicate minerals using the organosilicon cationic collector and starch depressant. Further studies of bauxite ore flotation were also conducted, and the reverse flotation separation process was adopted. The concentrates with the mass ratio of Al2O3 to SiO2 of 9.58 and Al2O3 recovery of 83.34% are obtained from natural bauxite ore with the mass ratio of Al2O3 to SiO2 of 6.1 at pH value of 11 using the organosilicon cationic collector and starch depressant.

Glass-forming ability, sinter-crystallization behavior and microwave dielectric properties of MgO-B2O3-(Al2O3)-SiO2 glass-ceramics

The present work aims to survey sinterability, crystallization behavior and microwave dielectric characteristics of MgO-B2O3-SiO2 glass-ceramics in the presence of 1–10 weight ratios of Al2O3. It was shown that changing the base composition and addition of Al2O3 led to an increase in the glass-forming potential. Fully densified glass-ceramics were achieved by sintering below 950°C from all selected compositions. During sintering, magnesium borate and magnesium silicate were formed in all specimens whilst cordierite was also crystallized in the specimens contained >5 weight ratios of Al2O3. Based on the FESEM observation, magnesium borate and magnesium silicate adopted a nanometric spherical morphology and cordierite had a platelet-like morphology.Due to the increased interface areas between crystalline phases and consequent intensified space charge polarization, addition of Al2O3 to the studied compositions did not affect dielectric properties, positively. However, the microwave dielectric characterization confirmed the suitability of the fabricated glass-ceramics as low-permittivity fully dense dielectric substrates.

Behaviour of spinel-forming DVM using crucible induction furnaces. A case study on material failure

This article contributes to the understanding of the sintering behaviour of spinel forming dry vibrating mixes (DVM) that are in common use in crucible induction furnaces (CIF) for metallurgic treatment. At present, an unwanted sintering of the DVM as far as to the cold face is reported from the industry. For safety reasons it is indispensable that an unaffected layer is remaining at the cold face of the lining. If not, the material becomes brittle and the risk of crack formation gets unacceptable. The access of liquid melt to the induction coil may cause severe accidents that destroy the furnace which bears the risk of industrial injury.Systematic research on breakout materials by means of SEM-supported microtextural and microanalytical investigations come to the result that a sintering occurs already in areas of the lining where the prevailing temperature could not have exceeded 300°C. Furthermore, it can be carved out that the sintering at the cold face is caused by the formation of spinel. This result is in contradiction to the generally accepted opinion that the spinel formation is kinetically hampered at temperatures lower than 900°C and should not occur. The increased MgO:Al2O3 ratios of the newly formed spinels indicate lower crystallization temperatures. The gradual transformation starts with marginal dissolution of the magnesia grains at the cold face and progrades with the development of skeleton structures of matrix spinels.The spinel formation is favoured of different components as chemical additives, a reduced atmosphere, hydration, and a momentary overheating. However, it is suspected that water and short-term overheating, respectively, play the key role since other known major agents as untypical oxides, and in particular fluorides and chlorides can be excluded by their erratic occurrence. We identified water as a primary unwanted additive which left typical microstructures in magnesia grains of the studied lining breakouts.

The formation of crystalline phases in metakaolin-based geopolymers in the presence of sodium nitrate

Geopolymers generated by alkali-activation of amorphous aluminosilicate sources are considered as an alternative immobilizing matrix for hazardous and nuclear wastes. Low and intermediate level nuclear waste streams are often highly alkaline saline solutions containing various concentrations of nitrate salts. The aim of the research project presented here was to study the effect of nitrate ions on the formation and evolution of metakaolin-based geopolymeric systems at moderate temperatures, i.e., at 40 °C. Metakaolin was alkali-activated using NaOH solutions of varying concentrations, yielding H2O:OH- ratios of 5.50, 9.15, 13.75, and 27.50. Sodium nitrate was added to the activation solutions at a constant [NO3 −]: [OH−] ratio of 0.25. Most geopolymeric mixtures were designed to obtain a Na2O:Al2O3 ratio of 1.00 for nitrate-free mixtures, or 1.25 for those including sodium nitrate. In addition, the effect of deviation from these values (Na2O:Al2O3 ratios of 0.84 and 1.20 for nitrate-free samples, 1.04 and 1.50 for nitrate-bearing samples) was also studied. The samples were cured in sealed containers at 40 °C for periods ranging from 1 day to 3 months. The products were characterized by X-ray diffractometry, Fourier transform mid-infrared spectroscopy, and scanning electron microscopy as well as by compressive strength measurements. The results demonstrate the influence of composition, alkalinity, SiO2:Al2O3 ratio, Na2O:Al2O3 ratio, nitrate concentration, and curing times on the mineralogy of the geopolymeric matrix. Various crystalline phases such as zeolite A, zeolite X, and nitrate-bearing phases, namely nitrate sodalite and nitrate cancrinite, were identified among the reaction products. The sequence of phase evolution in these geopolymeric systems was elucidated.

The effect of support type on the activity of zeolite supported iron catalysts for the decomposition of ammonia

The catalytic decomposition of ammonia was studied over zeolite supported iron catalysts regarding the hot gas cleaning requirements of coal/biomass to liquid processes. Catalysts were prepared on different zeolite frameworks (HZY, HZβ and HZSM5 with SiO2 to Al2O3 ratios of 5.2, 38 and 280) and tested. Brighter grains in the SEM images of Fe/HZSM5 catalyst were noticed to be the iron aggregates on the external surface. Any indicative brighter grains were not detected in the SEM images of Fe/HZβ and Fe/HZY catalyst meaning that iron might be dispersed well and attached to the aluminum sites. The FeOx cluster size was considered to be dependent on the textural properties of the zeolites. The absence of α-iron (bcc) phase on the Fe/HZY catalyst upon reduction was interpreted as the strong interaction of iron with the aluminum sites of HZY. This interaction might provide the stabilization of FeO phase by preventing its further transformation to metallic iron. The reduction of stabilized FeO to metallic iron on Fe/HZY catalyst upon reaction seemed to involve a reaction between iron oxides and non-framework aluminum species like Al(OH)2+, Al(OH) 2 + , AlO+, AlOOH etc. leading to iron aluminate (FeAl2O4)-like clusters. The highest activity over the Fe/HZβ catalyst might be due to the better hydrothermal stability of zeolite Hβ compared to zeolite HY regarding their aluminum contents. The role of the zeolite was probably to maintain good dispersion of active iron clusters without considering support effect on N–H bond breaking. Therefore, the best coordination environment for active iron species and improved iron cluster interactions can be ensured over zeolite Hβ framework.

Novel Two-Step Process for the Production of Renewable Aromatic Hydrocarbons from Triacylglycerides

A two-step process was developed for the production of aromatic hydrocarbons from triglyceride (TG) oils. In the first reaction step, TG (soybean) oil was noncatalytically cracked and purified by distillation to produce an organic liquid product (OLP). The resulting OLP was then converted into aromatic compounds in a second reaction using a zeolite catalyst, HZSM-5. In this second reaction, three main factors were found to influence the yield of aromatic hydrocarbons: the SiO2:Al2O3 ratio in the HZSM-5, the reaction temperature and the OLP-to-catalyst ratio. Upon cursory optimization, up to 58 w/w% aromatics were obtained. Detailed analyses revealed that most of the alkenes and carboxylic acids, and even many of the unidentified/unresolved compounds, which are characteristic products of noncatalytic TG cracking, were reformed into aromatic hydrocarbons. Instead of BTEX compounds, which are the common products of C2–C8 alkene and other feedstock reforming with HZSM-5, longer-chain alkylbenzenes dominated t...

Effect of Silica to Alumina Ratio on the Compressive Strength of Class C Fly Ash-Based Geopolymers

This study investigated the effect of silica to alumina ratio on the compressive strength of geopolymer. The high calcium fly ash (Class C, ASTM 618) wastes from Mae Moh Thailand power plant, which is SiO2 (30.97%) and Al2O3 (17.16%)-rich materials was employed as the main solid part to prepare geopolymers, apart from kaolinite. The combination of sodium hydroxide (NaOH), sodium silicate (Na2SiO3) solution, and distilled water as 1:1:4 mass ratios were used as the liquid activator. The curing temperature in the oven was fixed at 75oC and varied curing time for 24, 48, 72 and 96 hours. Further curing was done at room temperature for 28 days before characterizations. XRD study of synthesized geopolymers showed a hump of not well-defined peaks and some major peaks of quartz, and unreacted kaolinite indicating the incomplete geopolymerization reaction. Infrared study showed the Al-O-Si and Si-O-Si bonds in all geopolymers samples. The compressive strength of geopolymer increased from 32 to 40 MPa when the ratio of SiO2 : Al2O3 was increased from 2.60 to 2.65. However, the compressive strength was decreased after increasing the SiO2 : Al2O3 ratio from 2.65 to 3.0. The highest compressive strength was found when the SiO2 : Al2O3 ratio was 2.65 with the curing condition at 75oC for 96 h which the samples also possessed high density.

Isomerization of verbenol oxide to a diol with para-menthane structure exhibiting anti-Parkinson activity

Isomerization of verbenol oxide to (1R, 2R, 6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol, which exhibits anti-Parkinson activity, has been investigated with large and medium pore zeolites, namely H-USY and H-ZSM-5 types of catalysts with different SiO2 to Al2O3 ratio in dimethylacetamide as a solvent. The catalysts were characterized with nitrogen adsorption, 27Al MAS NMR, pyridine desorption, XRD, SEM and TEM techniques. The main reaction product was the target diol with the highest selectivity of 52 % achieved with H-ZSM-5-23 (the last number corresponds to SiO2/Al2O3 ratio) at 49 % conversion of verbenol oxide. The catalyst deactivation was, however, extensive with medium pore zeolites, compared to large pore zeolites. The second highest selectivities to diol with H-USY-80 and H-ZSM-5-80 were about 47–50 mol% at 100 and 78 % of conversion, respectively, achieved at 140 °C within 3 and 5 h. The other main products were the corresponding cyclopentylhydroxyketone and oxetane. A reaction mechanism was proposed.

The measurement of the adhesion force between ceramic particles and metal matrix in ceramic reinforced-metal matrix composites

This paper presents the method for measurement of the adhesion force and fracture strength of the interface between ceramic particles and metal matrix in ceramic reinforced-metal matrix composites. Three samples with the following Cu to Al2O3 ratio (in vol.%) were prepared: 98.0Cu/2.0Al2O3, 95.0Cu/5.0Al2O3 and 90Cu/10Al2O3. Furthermore, microwires which contain a few ceramic particles were produced by means of electro etching. The microwires with clearly exposed interface were tested with use of the microtensile tester. The microwires usually break exactly at the interface between the metal matrix and ceramic particle. The force and the interface area were carefully measured and then the fracture strength of the interface was determined. The strength of the interface between ceramic particle and metal matrix was equal to 59±8MPa and 59±11MPa in the case of 2% and 5% Al2O3 to Cu ratio, respectively. On the other hand, it was significantly lower (38±5MPa) for the wires made of composite with 10% Al2O3.

Improvement of performance in low temperature solid oxide fuel cells operated on ethanol and air mixtures using Cu–ZnO–Al2O3 catalyst layer

Anode-supported single-chamber solid oxide fuel cells with and without Cu–ZnO–Al2O3 catalyst layers deposited on the anode support have been operated on ethanol and air mixtures. The cells consist of gadolinia-doped ceria electrolyte, Ni-doped ceria anode, and La0.6Sr0.4CoO3-δ-doped ceria cathode. Catalyst layers with different Cu–ZnO–Al2O3 ratios are deposited and sintered at several temperatures. Since the performance of single-chamber fuel cells strongly depends on catalytic properties of electrodes for partial oxidation of ethanol, the cells are electrochemically characterized as a function of the temperature, ethanol-air molar ratio and gas flow rate. In addition, catalytic activities of supported anode, catalytic layer-supported anode and cathode for partial oxidation of ethanol are analysed. Afterwards, the effect of composition and sintering temperature of catalyst layer on the cell performance are determined. The results indicate that the cell performance can be significantly enhanced using catalyst layers of 30:35:35 and 40:30:30 wt.% Cu–ZnO–Al2O3 sintered at 1100 °C, achieving power densities above 50 mW cm−2 under 0.45 ethanol-air ratio at temperatures as low as 450 °C. After testing for 15 h, all cells present a gradual loss of power density, without carbon deposition, which is mainly attributed to the partial re-oxidation of Ni at the anode.

Scale-up of NaA zeolite membranes on α-Al2O3 hollow fibers by a secondary growth method with vacuum seeding

NaA zeolite membranes were prepared by secondary growth method on the outer surface of α-Al2O3 hollow fiber supports. Vacuum seeding method was used for planting zeolite seeds on the support surfaces. Hydrothermal crystallization was then carried out in a synthesis solution with molar ratio of Al2O3:SiO2:Na2O:H2O=1:2:2:120 at 100°C for 4h. Effects of seeding conditions on preparation of hollow fiber NaA zeolite membranes were extensively investigated. Moreover, hollow fiber membrane modules with packing membrane areas of ca. 0.1 and 0.2m2 were fabricated to separate ethanol/water mixture. It is found that the thickness of seed layer is obviously affected by seed suspension concentration, coating time and vacuum degree. Close-packing seed layer is required to obtain high-quality membranes. The optimized seeding conditions (seed suspension mass concentration of 0.5%–0.7%, coating time of 5s and vacuum degree of 10kPa) lead to dense NaA zeolite layer with a thickness of 6–8μm. Typically, an as-synthesized hollow fiber NaA zeolite membrane exhibits good pervaporation performance with a permeation flux of 7.02kg·m−2·h−1 and separation factor >10000 for separation of 90% (by mass) ethanol/water mixture at 75°C. High reproducibility has been achieved for batch-scale production of hollow fiber NaA zeolite membranes by the hydrothermal synthesis approach.

Nitration of 1,3,3-trimethyl-1-phenylindane on mesoporous aluminosilicates

Nitration of 1,3,3-trimethyl-1-phenylindane (phenylindane) by nitric acid of different concentration over mesoporous aluminosilicates with the molar ratios SiO2 : Al2O3 = 20, 40, and 80 was studied. The effects of the SiO2 : Al2O3 and phenylindane : nitric acid ratios, the concentration of nitric acid, and temperature on the conversion of phenylindane and the yield of dinitrophenylindane were revealed. The aluminosilicate samples with a SiO2 : Al2O3 ratio of 20 are shown to have the highest activity. In the presence of these samples, the conversion of phenylindane reaches 100% with a selectivity of formation of 5and 6-nitro-1-(4´-nitrophenyl)1,3,3-trimethylindanes close to 80% (70% nitric acid, 100 °C).