Presence Of Tetralin Research Articles

Effect of Hydrogen-Donor of Heavy Crude Oil Catalytic Aquathermolysis in the Presence of a Nickel-Based Catalyst

The transformations of oil components from the Zyuzeevskoye field during catalytic aquathermolysis in the presence of a nickel-containing catalyst precursor and hydrogen donors were studied. It was found that the yield of gasoline and diesel fractions increased by more than 36% in the case of catalytic aquathermolysis in the presence of tetralin. The maximum conversion of asphaltenes was achieved with a simultaneous slowing down of coke formation by four times. The calculation of the structural-group parameters of initial asphaltenes and the products of thermal cracking and catalytic aquathermolysis was made, and the hypothetical construction of their molecular structures was proposed. It was established that the phase composition, ratio, and morphology of nickel catalysts after catalytic aquathermolysis (CA) and catalytic aquathermolysis with tetralin (CA+T) depend on the amount of “free” hydrogen and are represented by Ni0.96S and Ni9S8.

Influence of Naphthenic Hydrocarbons and Polar Solvents on the Composition and Structure of Heavy-Oil Aquathermolysis Products

Estimates of the conventional proven hydrocarbon reserves show a tendency toward depletion, and in the near future they will be insufficient to meet the ever-growing global energy demand. The problem of crude oil deficiency can be solved by involving unconventional hydrocarbon resources in both recovery and refinery. However, the hydrogen deficiency of heavy oil and natural bitumen requires technical and technological solutions. Therefore, the hydrogen-donating capacity of water and solvents, particularly in reservoir conditions, is very attractive. In this paper, we study the hydrogen-donating capacity of naphthenic and polar solvents during hydrothermal treatment of heavy oil from Ashal’cha reservoir (Republic of Tatarstan, Russia). It was established that naphthenic solvents significantly influence the viscosity reduction due to the destructive hydrogenation of resins and asphaltenes. Among naphthenic solvents, decalin significantly increases the amount of evolved gases, particularly C4–C10 isomers and aromatics. However, the maximum evolved gases among all of the used solvents correspond to formic acid. The results of elemental analysis revealed that the H/C ratio rises in crude oil samples after hydrothermal treatment in the presence of cyclohexane and decalin. FT-IR spectral indices revealed an increase in crude oil aliphaticity in case of using solvents from the cyclohexane–tetralin–decalin series due to the cleavage of carbon–heteroatom bonds in aliphatic substitutes of resins and asphaltenes. Significant changes in the FT-IR spectra of crude oil are observed in the presence of tetralin.

Conversion of V-porphyrin in asphaltenes into V2S3 as an active catalyst for slurry phase hydrocracking of vacuum residue

The asphaltene hydrocracking (HCK) was carried out at 693 K and 11.0 MPa H2 to examine the phase transformation of V species contained in the asphaltene and the catalytic activity of the resulting V compounds in the HCK. The V K-edge X-ray absorption near edge structure spectroscopy (XANES) was employed to identify the V species dispersed in the asphaltene and the phase transformation with respect to the HCK conditions. The V in asphaltene was observed as a form of the vanadyl-porphyrins (VO-porphyrin) that was converted into V2S3 during the HCK in the presence of tetralin, whereas the VO-porphyrin was not converted fully into the V2S3 in the absence of tetralin due to its isolation within a coke. In addition, the catalytic activity of V2S3 formed from VO-porphyrins in the asphaltene was confirmed by an increase of H2 consumption and asphaltene conversion in the recycle tests of the vacuum residue (VR) HCK at 693 K and 11.0 MPa H2 in the presence of tetralin. The intrinsic catalytic activity of the dispersed V2S3 in the VR HCK was measured at 693 K and 11.0 MPa H2 in presence of the model V precursor of 0.113 mmol VO(acac)2, exhibiting a TOFT of 0.080 s−1 and the asphaltene conversion of 30%. The XANES and TEM analysis confirmed that the V precursor undergoes transformation into nano-scaled V2S3 particles in course of the VR HCK. Therefore, it was demonstrated that the VO-porphyrin in asphaltenes can be converted into the dispersed V2S3 catalysts during the VR HCK.

Effect of Waste Type on Liquid Products Yields and Quality Obtained by Co-Liquefaction of Coal and Waste

The need to find alternative liquid fuels more environmental friendly and with a more secure supply, has led to the idea of studying the conversion of carbonaceous wastes, like plastics, used tyres and biomass into liquid products to be used as fuels or as raw materials for several industries. As coal liquefaction is a well-known process to produce liquid products, coal blended with used tyres and plastic wastes was co-liquefied. Coal impregnated with 1 % wt. of molybdenum was used in co-liquefaction tests blended with 50 % wt. of used tyres or with the main plastics present in municipal solid wastes: PE (polyethylene), PP (polypropylene), PS (polystyrene) and a mixture of these plastics. The results obtained showed that all wastes promoted coal liquefaction. However, liquids yield and quality improved with the presence of plastics, while more solids were obtained when used tyres were used. Coal blends with PS wastes led to the highest liquid yield (74 % wt.) and conversion (88 % wt.) The presence of PE favoured the formation of linear alkanes, while PS promoted the formation of more aromatic compounds, which is in agreement with these plastics initial molecular structure. Some co-liquefaction tests were done in presence of tetralin, a hydrogen donor solvent that promoted the formation of liquids. Tetralin allowed increasing liquids yields obtained with plastics to values higher than 90 % wt., while in co-liquefaction of coal with used tyres led to liquids yields around 77 % wt.

Investigation of Thermolysis Products of Some N‐Arylthiophene‐2‐carboxamidoximes by Analytical and Spectroscopic Analyses

AbstractN‐arylthiophene‐2‐carboxamidoxime derivatives (a‐e) were synthesized by using two methods and then subjected to thermolysis at 200–250 °C for 2 h under nitrogen atmosphere either alone or in the presence of tetralin and/or naphthalene as radical scavengers yielded imidazole, oxazole, triazine and amide derivatives. The pyrolysates from both reactions were separated with their constituents by column chromatography and analyzed then identified 1H NMR, 13C NMR and GC‐MS. A plausible mechanism is suggested through two competitive pathways involving the homolysis of N‐O and/or C‐N bonds to account for the thermolysis products.

Short time synthesis of titania modified-CMK-3 carbon mesostructure as support for Ir-catalyst applied in catalytic hydrotreating

Abstract Ti-CMK-3 carbon mesoporous was prepared using a novel synthesis method. This new method avoids the hard template synthesis used commonly. The method developed here, allows to reduce time, energy consumptionand cost. Structural and textural characterization of the titanium modified-mesoporous carbonwas performed by N2 adsorption, XRD, UV–vis-DRS, Raman spectroscopy and TEM. The characterization results indicated that the textural and structural properties of the material synthesized by the short time method are comparable with the properties of the material prepared by the hard template method. Ti modified-mesoporous carbon was used as support of the iridium nanoparticles, in order to prepare a catalyst to be tested in model hydrotreating reactions. The catalyst obtained by wet impregnation with iridium acetylacetonate were characterized by ICP-AES, H2 chemisorption, TEM, XPS and FTIR of adsorbed pyridine. The high Ir dispersion and small particle size, along with the moderate Lewis acidity generated by the presence of titanium in the support, were responsible for the good performance and stability of the catalyst in the hydrogenation of tetralin in presence of nitrogen compounds. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for HDT reactions.

Effect of solvent and atmosphere on product distribution, hydrogen consumption and coal structural change during preheating stage in direct coal liquefaction

In order to study the necessity of hydrogen source at preheating stage of direct coal liquefaction, product distribution, hydrogen consumption, and coal structural change of Hami sub-bituminous coal (HM) with 1-methylnaphthalene (1-MN) and tetralin respectively were investigated under hydrogen and nitrogen atmosphere. The results show that oil could be generated from coal itself with 1-MN under N2 and the yield increases with temperature rising at the range of 200–350°C, whereas only 4.94% oil is obtained at 350°C. Moreover, volatiles and H/C ratios of pretreated coal decrease dramatically above 250°C. At 350°C, preheating with gas phase H2 in 1-MN promotes oil yield to 10.42%. In the presence of tetralin, oil yields of 28.55% and 26.15% are achieved under N2 and H2 at 350°C, respectively. Approximately same total hydrogen consumption is observed under N2 and H2 with tetralin, and the hydrogen consumption from tetralin is higher than that from H2. With the addition of hydrogen sources, aromaticity of the residual solid decreases and reactivity increases. Decomposition of oxygen-containing functional groups like COOH and CO is not affected by the preheating solvent and atmosphere but relies on temperature. In addition, pretreated solid samples achieve increasing oil yield and conversion in the subsequent liquefaction with their rising thermal reactivity and H/C ratios.

Hydrogenation of tetralin in presence of nitrogen using a noble-bimetallic couple over a Ti-modified SBA-15

Monometallic Pt- and bimetallic Pt-Ir-modified Ti-SBA-15 were used in the hydrogenation of tetralin to decalin in the presence of 150ppm of N as quinoline and indole at 250°C and 15atm of pressure of hydrogen, using a Parr reactor. The catalyst was synthesized using sol-gel method and Ti was added during the synthesis using Tetraethyl Orthotitanate. Pt/Ir was added by wetness impregnation. The catalysts prepared were extensively characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–vis-DRS, Raman spectroscopy, XPS, TEM-EDS and TPR. UV–vis-DRS and Raman spectroscopy confirmed that Ti was incorporated in tetrahedral coordination in the framework of the SBA-15. The analysis showed that the mesoporous structure was maintained after metal incorporation and Ti incorporation helps to reduce significantly the size of the metals clusters and improves its dispersion considerably. Pt-Ir/Ti-SBA-15 was the most active catalyst. The experimental data were quantitatively represented by a modified Langmuir-Hinshelwood type rate equation. The preliminary results show these materials as a promising catalyst for HDT reactions.

Role of Hydrogen Transfer during Catalytic Copyrolysis of Lignin and Tetralin over HZSM-5 and HY Zeolite Catalysts

In the present study, catalytic pyrolysis of lignin and tetralin was explored in a tandem micropyrolyzer using HY and HZSM-5 as the catalysts. Tetralin is an effective hydrogen donor at atmospheric pressure and its molecular size is bigger than the static pore size of HZSM-5 but smaller than that of HY zeolite. Therefore, copyrolysis of lignin and tetralin is also useful in understanding the role of hydrogen transfer in the zeolites related to shape selectivity. A strong synergistic effect between lignin and tetralin was found with HY zeolite as catalytic coke decreased from an additive yield of 12.72 C% to an experimental yield of 3.8 C%, whereas the aromatic hydrocarbon yield increased from 48.79 C% to 66.23 C% at catalyst temperature of 600 °C. Carbon balance of the measurable pyrolysis products was high because lignin-derived phenols were effectively deoxygenated by HY zeolite in the presence of tetralin. Hydrogen transfer from tetralin to phenols within HY zeolite pores changed the mode of oxygen rem...

Thermolysis of some N-arylbenzamidoximes: Mechanistic studies for formation of anilide, oxazole and imidazole derivatives

The thermolysis of N-2-pyridylbenzamidoxime I under nitrogen atmosphere for 5 hours gives rise to 2-phenyl-1H-imidazo[4,5-b]pyridine and N-(pyridin-2-yl)benzamide as the major products (52.4 and 18.11%, respectively), in addition to 2-hydroxy pyridine, benzonitrile, benzoic acid, 2-aminopyridine, 2-phenyloxazolo[4,5-b]pyridine, 9H-pyrrolo[2,3-b:5,4-b’]dipyridine and 2,4,6-triphenyl-1,3,5-triazine. Also, heating N- α-naphthylbenzamidoxime II under the same conditions gave N-(α-Naphthyl)benzamide, 2-Phenyl-3H-naphtho[2,1-d] imidazole as the major products besides benzonitrile, benzoic acid, α-naphthylamine and 2-phenylnaphtho[1,2-d]oxazole. In the presence of tetralin, I gave 1-hydroxytetralin, α-tetralone and 1,1’-bitetrayl besides the previous products. The reaction and isolated products have been interpreted in terms of a free radical mechanism involving the homolysis of N-O and/or C-N bonds. Thermolysis of N-arylbenzamidoximes I and II gives rise to 2-phenyl-1H-imidazo [4,5-b]pyridine, N-arylbenzamides and 2-Phenyl-3H-naphtho[2,1-d]imidazole as the major products besides other acyclic and cyclic products. The isolated products have been interpreted in terms of a free radical mechanism involving the homolysis of N-O and/or C-N bonds.

Effect of initial coal particle size on coal liquefaction conversion

In coal liquefaction process initial coal particle size can be considered as one of the important process parameters. In this work, particles of coal are prepared by pulverisation and separation into different particle size ranges below 45 to 1,000 µm. Since conventional batch autoclave is not suitable for short contact time experiments, as the time required for the autoclave to reach the reaction temperature can be substantial, the liquefaction runs were investigated with a rapid injection reactor designed specifically for investigating the effect of initial particle size on liquefaction conversion. A Canadian coal was examined in a tubular bomb reactor in presence of tetralin at 400°C for a short reaction time (5 min) with pressure of 6 MPa under nitrogen atmosphere. The results indicated that total conversion obtained during the liquefaction changed according to the different particle size, and optimum particle size (150-212 µm) was detected for the liquefaction condition. [Received: November 27, 2014; Accepted: August 22, 2015]

Facilitated and selective oxidation of thiophenic sulfur compounds using MoOx/Al2O3–H2O2 system under ultrasonic irradiation

Oxidative desulfurization of thiophenic sulfur compounds of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) with MoOx/Al2O3 catalyst and H2O2 oxidant has been facilitated and more selective under ultrasonic irradiation. The catalyst with the optimum 10% of Mo loading consisted of isolated tetrahedral molybdenum oxide species based on FTIR analysis. The increase of Mo loading to 15% and 20% caused to generation of polymolybdate and MoO3 crystals which decreased desulfurization activity. Sonication enhanced the apparent reaction rate constants in oxidation of all three sulfur compounds. An increase in the Arrhenius factor (A0), which is the total number of collisions per second, could explain the acceleration in the rate constants by sonication. The apparent activated energy (Ea) of BT oxidation was reduced from 96.6 to 75.3kJ/mol by using ultrasound. This indicated that ultrasound had also a chemical effect, like a catalytic influence, in the acceleration of BT removal. DBT oxidation was reduced when investigated in the presence of tetralin, naphthalene and 2-methyl naphthalene as the model aromatic compounds of actual light oils. A higher selectivity toward DBT elimination in the presence of aromatics was obtained by sonication when compared with the silent treatment. Ultrasound cleaned the catalyst surface from adsorbed aromatics. On the basis of the obtained results, a mechanistic proposal for this desulfurization was explained. Oxidation was performed by nucleophilic attack of sulfur atom to the molybdenum peroxide species of tetrahedral molybdates, which was more advanced by sonication.

Catalytic hydroliquefaction of charcoal CCB (copper, chromium and boron)-treated wood for bio-oil production: Influence of CCB salts, residence time and catalysts

Thermochemical processes offer a feasible option for wood waste management and the recovery of a variety of useful chemicals. In this paper, hydroliquefaction with the use of catalysts was optimized to provide bio-oil from CCB-treated wood by reducing gaseous emissions of copper, chromium and boron (hazardous materials). In addition, the influence of CCB salts, catalysts (Al2O3, Na2CO3, MgO and CaCO3) and residence time on the hydroliquefaction process was investigated. For this, hydroliquefaction of charcoal obtained by slow pyrolysis of CCB-treated wood was conducted under hydrogen pressure in presence of tetralin. The results showed that CCB salts and catalysts increase the yield of bio-oil compared to hydroliquefaction of charcoal from untreated wood. It was also observed, that the use of catalysts improves the residence time during the process. Among the catalysts employed, Al2O3 appears to be the most effective. Furthermore Na2CO3 promotes the formation of gaseous species particularly CH4. Analyses of hazardous materials in charcoal residue (coke) illustrate their transfer to the bio-oil with the increase of bio-oil yield and residence time except when Al2O3 was using. The bio-oil obtained contains aromatic compounds.

Upgrading vacuum residuum by combined sonication and treatment with a hydrogen donor

Vacuum residuum was upgraded in an ultrasonic reactor of our own design. We found that during sonication in the absence of a hydrogen donor, the viscosity of the vacuum residuum is reduced by 10.98%; without sonication but in the presence of tetralin, it is reduced by 30.9%; and with combined tetralin treatment and sonication, the viscosity is reduced by 39.27%. The synergistic effect of ultrasound and tetralin results in a product with more stable viscosity, higher percentage of light components, lower density and lower pour point than obtained by separate application of these technologies.

Catalytic Thermal Liquefaction of Oil Shale in Tetralin

A short review on the publications concerning thermal liquefaction of solid fuels in the environment of hydrogen donor solvents and catalysts is compiled. New experimental results on the catalytic thermal dissolution of oil shale in tetralin as the hydrogen donor solvent in a batch autoclave are presented. The impacts of pyrolysis temperature, duration, and catalyst type on the yields of gas, maltenes, asphaltenes, preasphaltenes, and coke in the presence of tetralin are described.

Markers for secondary reactions of migrated crude oil on carbonaceous surfaces

A high abundance of ethyl substituted aromatic hydrocarbons (HCs) relative to their methyl counterparts is an unusual feature of some crude oils. Enhanced stability of ethyl aromatic HCs in the presence of tetralin was observed when individual ethylated compounds were heated with activated carbon in sealed tubes over a range of 170–340°C. In addition, conversion of the common distribution of alkyl aromatic HCs to an unusual distribution, containing a higher relative abundance of ethyl compounds, was demonstrated by way of closed system heating of the aromatic fraction of a crude oil in the presence of activated carbon. The conditions for this unusual process require the presence of hydrogen donor components, which selectively limit the reaction and depletion of ethylated compounds relative to methylated compounds. The phenomenon has been shown to occur for substituted benzenes, naphthalenes, phenanthrenes and biphenyls. Enhanced abundance of ethyl aromatic HCs relative to their methylated counterparts is therefore proposed as an indicator for secondary reactions of migrated crude oil that has undergone thermal alteration after contact with carbonaceous surfaces in sediments. Application of these principles to selected crude oils and sediment extracts from the Carnarvon and Cooper/Eromanga Basins (Australia) indicates that significant secondary reaction of migrated crude oil has occurred.

Liquid fuel from waste polyolefins part I: Thermal and pressure degradation of waste polyolefins in tetralin as H-donor model system

In the paper, the results of the study on a laboratory process of thermal and pressure destruction of waste polyolefins in the presence of tetralin as a model hydrogen donor are presented. Waste polyolefins were termally cracked in the presence of a catalyst and hydrogen donor (tetralin) in a closed autoclave (volume: 1 dm 3) in the anaerobic atmosphere. The process temperature was maintained 400–500 °C. The pressure at the end of process, depending on the feed composition, was 10–15 MPa. As a result, a desirable liquid fraction was obtained. A product of waste polyolefin decomposition in the presence of tetralin is a complex mixture of hydrocarbons. The analysis of products has shown satisfactory decomposition of polymer chains as well as hydrogenation of unsaturated structures. Low sulphur and chlorine contents in the obtained fractions constitute a highly positive effect, especially in a fuel aspect. A significant disadvantage here is a considerable number of tetralin conversion reactions. The use of this hydrogen donor for technological purposes is not possible as the final fraction must be cleared from disproportionation products or hydrogen donor decomposition products.

Proteomic and transcriptional characterization of aromatic degradation pathways in Rhodoccocus sp. strain TFB

Rhodococcus sp. strain TFB is a versatile gram-positive bacterium able to grow on a wide variety of aromatic compounds as carbon and energy sources. Since the strain is refractory to genetic analysis, a proteomic approach was used to study the metabolic pathways involved in the catabolism of such compounds by analyzing differentially induced proteins. The most marked difference was observed when the proteome profiles of phthalate-grown cells were compared with those cultured in the presence of tetralin- or naphthalene, suggesting that different metabolic pathways are involved in the degradation of mono- and polyaromatic compounds. Comparison with the proteome of glucose-grown cells indicated that each pathway was specifically induced by the corresponding aromatic compound. A combination of proteomics and molecular biology led to the identification of 14 proteins (65-80% identical to known Pht proteins) that describe a complete pathway for the catabolism of phthalate to central metabolites via intradiol cleavage of protochatechuic acid. Chaperonins were also induced in phthalate-grown cells, indicating that growth on this compound induces a stress response. Absence of catabolite repression by glucose was observed by both transcriptional and proteome analysis, suggesting that Rhodococcus sp. strain TFB may have advantages over other tightly regulated strains in bioremediation.

Regulation of tetralin biodegradation and identification of genes essential for expression of thn operons.

The tetralin biodegradation genes of Sphingomonas macrogolitabida strain TFA are clustered in two closely linked and divergent operons. To analyze expression of both operons under different growth conditions, transcriptional and translational gene fusions of the first genes of each operon to lacZ have been constructed in plasmids unable to replicate in Sphingomonas and integrated by recombination into the genome of strain TFA. Expression analysis indicated that the transcription of both genes is induced in similar ways by the presence of tetralin. Gene expression in both operons is also subjected to overimposed catabolic repression. Two additional genes named thnR and thnY have been identified downstream of thnCA3A4 genes. ThnR is similar to LysR-type regulators, and mutational analysis indicated that ThnR is strictly required for expression of the thn operons. Unlike other LysR-type regulators, ThnR does not repress its own synthesis. In fact, ThnR activates its own expression, since thnR is cotranscribed with the thnCA3A4 genes. ThnY is similar to the ferredoxin reductase components of dioxygenase systems and shows the fer2 domain, binding a Cys4[2Fe-2S] iron sulfur center, and the FAD-binding domain, common to those reductases. However, it lacks the NAD-binding domain. Intriguingly, ThnY has a regulatory role, since it is also strictly required for expression of the thn operons. Given the similarity of ThnY to reductases and the possibility of its being present in the two redox states, it is tempting to speculate that ThnY is a regulatory component connecting expression of the thn operons to the physiological status of the cell.

A solvothermal route to CdS nanocrystals

A novel solvothermal route for the preparation of organic soluble CdS nanocrystals, involving the reaction of cadmium stearate with sulfur in the presence of tetralin has been described. Tetralin in the presence of S gives H 2S, getting aromatized to naphthalene. By using trioctylphosphineoxide as the capping agent, nanocrystals of 4 nm are obtained. Use of dodecanethiol cap results in 5 nm as well as 10 nm nanocrystals which can be separated readily. The nanocrystals have the cubic zinc blende structure and exhibit blue shifts of the absorption maximum.