Nazarova, Galina Yurievna

Stebeneva, V. I.

Electronic archive of Tomsk Polytechnic University

XVII Международная научно-практическая конференция имени профессора Л.П. Кулёва528Quantum-ChemiCal modelinG of the eleCtroniC struCture of aromatiC hydroCarbons of CatalytiC CraCkinG of VaCuum distillateV.I. Stebeneva, G.Y. NazarovaScientific Supervisor – DSc, Professor, E.N. Ivashkina Linguistic Advisor – PhD, Assistant, Engineer, N.S. BelinskayaNational Research Tomsk Polytechnic University 634050, Russia, Tomsk, st. Lenina, 30, stebeneva_valeriya@mail.ruThe catalytic cracking of crude oil is one of the advanced cracking processes (over 80%). Solving the problem of production optimizing using math-ematical and kinetic-thermodynamic modeling al-lows to obtain products that satisfy to international environmental, economic and operational require-ments.The work objective is definition of thermody-namic parameters to developing mathematical mod-el of catalytic cracking reactions, involving aromat-ic hydrocarbons of vacuum distillate.Aromatic compounds have a significant influ-ence on the yield and composition of the catalytic cracking products. In order to determine the most probable chemical reactions of aromatic hydrocar-bons of catalytic cracking of vacuum distillate was performed the thermodynamic analysis of reac-tions with using the methods of quantum chemistry (DFT/B3LYP, 6-31G).Initially, the aromatic content of the feedstock for catalytic cracking has been established exper-imentally using the liquid-adsorption chromato-graphic fractionation. The concentration of aromat-ic hydrocarbons was 35.57 wt %. The hydrocarbon structures were determined using gas chromatogra-phy-mass spectrometer Hewlett Packard Gas Chro-matograph System 6890 with 5973 Mass Selective Detector and GC Chemstation software. Processing of gas chromatography-mass spectrometry results performed by the method of internal normalization without consideration of correction factors for each component.Modeling of aromatic hydrocarbons and cal-culation of thermodynamic parameters were per-formed at T = 848 K, P = 1.08 Mpa (temperature of reaction start) for the following reaction [1]:1) benzene dealkylation to form an olefin;2) cracking of iso-alkyl substituent on the middle of the molecule to form a iso- alkyl-substituted aromatics and olefin;3) cracking of alkyl substituent in the beta-position relative to the positively charged carbon atom of the benzene ringResults of the thermodynamic parameters cal-culation are shown in Table 1.Table 1 shows that reaction №3 characterized by most probable thermodynamic of chemical re-actions, due to formation of a stable tertiary carbo-table 1. The values of thermodynamic parameters for various reactions involving aromatics hydrocarbons№ Reaction type ∆G, KJ/mole ∆H, KJ/mole1 1-butylnonylbenzene ↔ benzene+tridecene-7 –82.54 64.382 1-butylnonylbenzene ↔ 1-octanebenzene + pentene-2 –88.07 59.113 1-butylnonylbenzene ↔ 1-pentylbenzene + octene-2 –97.43 55.331 1-methyldodecylbenzene ↔ benzene + tridecene-2 –67.54 82.372 1-methyldodecylbenzene ↔ 1-methylpentylbenzene + hexene-2 8.00 82.313 1-methyldodecylbenzene ↔ 1-ethylbenzene + dodecene-2 –76.11 74.491 1-pentiloktilbenzol ↔ benzene + tridecene-6 –82.69 64.352 1-pentiloktilbenzol ↔ 1-benzenenonane + butene –81.13 55.133 1-pentiloktilbenzol ↔ 1-hexylbenzene + heptene-2 –94.04 56.24table 2. The dependence of thermodynamic parame-ters from the number of carbon atoms in the alkyl substituentHydrocarbon∆G, KJ/mole∆H, KJ/mole1-ethylnonylbenzene –88.54 55.001-ethyldecylbenzene –91.93 54.941-ethylundecylbenzene –92.16 54.941-ethyldodecylbenzene –98.15 54.78 Секция 7.  Химия и химическая технология на иностранном языке529cation of benzene type. Then, the dependence of the thermodynamic parameters from the number of carbon atoms in the alkyl substituent of the benzene ring was determined for selected type of reactions.The results of Table 2 show that with increasing the number of carbon atoms in the alkyl substitu-ent also increases the thermodynamic probability of cracking reactions, due to the weakening of internal communication links in the alkyl substituent.reference1. Tilicheev M.D. Chemistry of cracking.– М.: Book-on-Demand, 2013.– P.269.eleCtroChemiCal oXidation of nitroPhenolsE.V. Sukhoroslova, E.V. Zangieva, A.B. IadykinaScientific superviser – PhD, Associate Professor, O.S. Kukurina Linguistic advisor – PhD, Associate Professor, O.S. KukurinaNational Research Tomsk Polytechnic University 634050, Russia, Tomsk, Lenina Avenue, 30, annaanna.borisovna@mail.ru, kukurina@tpu.ruPhenol and substituted phenolic compounds, especially nitro-derivatives are extremely toxic and namely nonbiodegradable pollutants. They are dis-charged in the effluent from the chemical process industries which are either manufacturing or using them. Thus the various techniques of phenolic pol-lutants destruction are still burning issues nowa-days. And chemical oxidation is considered to be the most universal method. The process of destructive pesticides oxidation is carried out in a laboratory installation, the basic unit of which is the electrochemical cell [1].To increase the rate of oxidation of toxic or-ganic substances and prevent stagnant zones in the reactor used continious stirring. The oxidation pro-cess is carried out in the kinetic region [2].The process of oxidative degradation was in-vestigated on nitrophenol. The substance to be sub-jected to oxidative degradation, dissolved in 80 ml of sulfuric acid and transfer into the apparatus. The concentration of the electrolyte may vary from 10 to 96 wt. %. A voltage is applied to the electrodes of the adjustable constant current source. During oxidation in reactor temperature can be increased up to the boiling point of the solution, in this case necessary to provide heat removal. At certain time intervals samples were taken for analysis [3].We carried out the identification of intermedi-ates and final products by means of UV spectropho-tometry, gas chromatography with mass selective detector and high performance liquid chromatogra-phy.During the experiment were obtained follow-ing data. This data show the presence of absorption bands at 210 nm – oxygenated compounds; 270 nm – phenol derivatives; 350 nm – nitrophenol.According to the chromatography data at 0 minute is the largest peak, with the peak decreases over time, this means that the nitrophenol concen-tration in the solution decreases. Delay time 8.53 minutes carboxylic acids. That is, the oxidation passes through their formation. Phenol delay time – 14, 76 minutes at peak chromatograms of phenol was not detected. As the peak of hydroquinone – 24.85 minutes.Thus the organic component of molecules is oxidized through intermediate products formation (such as acids, alcohols and aldehydes) up to simple compounds. At the same time some of these groups are destroyed on the cathode by reduction [4].Thus, according to UV-spectroscopy the ni-trophenol oxidation intermediates are phenol and carboxylic acids, and gas chromatograph with mass spectroscopy determines the carboxylic acids with-out phenol.fig. 1.  

Quantum-chemical modeling of the electronic structure of aromatic hydrocarbons of catalytic cracking of vacuum distillate

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