Vapor-liquid equilibrium data were measured isothermally in the near-azeotropic
region of the 2-methylpropan-2-ol + water + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide system at ...333.15, 343.15, and 353.15 K. The data were processed using a recently developed method based on a small number of experiments that provides a complete thermodynamic description of the azeotropic behavior. The parameters of the third-order Redlich-Kister equation were correlated with the ionic liquid concentration to determine an analytical dependence of both the azeotropic composition and the pressure.
Vapor-liquid equilibria were measured isothermally in the two title systems at 333.15, 343.15, and 353.15 K. A dynamic equilibrium still, allowing for the recirculation of both liquid and vapor ...phases was used. The data were correlated by means of the standard NRTL equation while considering the real behavior of the vapor phase, and with the use of the maximum likelihood procedure. Both the systems exhibited azeotropic behavior.
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Vapour–liquid equilibria – as total pressure data – were determined isothermally in the polystyrene + butan-2-one system at 323.15, 333.15, and 343.15 K using the microebulliometric method. The ...experimental data were correlated using the UNIQUAC-free volume model, and the applicability of two known predictive models was tested.
•We have measured new experimental data on vapour–liquid equilibria in diluted polymer + solvent system.•The polystyrene + butan-2-one system was investigated at three isotherms.•Data were correlated by means of the UNIQUAC-free volume equation.•UNIQUAC-FV parameters for new and literature data are proportional to temperature.•Prediction of phase equilibria was carried out with use of the GC-Flory EoS and the Entropic-FV models.
The major problem encountered in the petroleum industry lies in the proper thermodynamic representation of rather complex fluids. In this work, the UNIFAC group contribution method for predicting the ...properties of such fluids has been exploited as a basis for their description in terms of model compounds. Standard thermodynamic procedures are used to estimate the critical properties, acentric factors, and molecular weights for the model compounds. In such a way, the already available generalized methods can be used for calculations of the phase equilibrium in complex petroleum mixtures.
Vapour-liquid equilibria (VLE) were determined in the poly(methyl methacrylate) + 2-butanone system under isothermal conditions at 333.15, 343.15, and 353.15 K using an improved all-glass ...micro-ebulliometer with circulation of the liquid phase for the dynamic measurement of total pressure over liquid mixtures. The experimental data were correlated using the UNIQUAC-FV model and the applicability of three known predictive models was tested. It was found that only the UNIFAC-vdw-FV model gives excellent prediction of VLE for the studied system. Key words: vapour-liquid equilibrium, experimental data, polymer-solvent system, correlation, ebulliometer
Vapour-liquid equilibria (VLE) were determined in the polystyrene + toluene system under isothermal conditions at 363.15, 373.15, and 383.15 K using an improved all-glass microebulliometer with ...circulation of the liquid phase for the dynamic measurement of total pressure over liquid mixtures. The experimental data were correlated using the UNIQUAC-free volume model and the applicability of three known predictive models was tested. It was found that prediction of VLE using the GC-Flory equation of state, the UNIFAC-vdw-FV and the Entropic-FV model are of the same quality. Key words: vapour-liquid equilibrium, polymer-solvent system, ebulliometer, experimental data, correlation
U radu je dat pregled polimernih aditiva koji služe za sniženje tecišta i poboljšanje reoloških svojstava nafte i plinskog kondenzata. Opisane su temeljne vrste polimera koji se u te svrhe ...primjenjuju: polimeri na osnovi olefina, posebice etilena, kopolimeri vinil-acetata i alkil-fumarata, esteri akrilne i metakrilne kiseline te polimeri na osnovi anhidrida maleinske kiseline. Prikazan je mehanizam djelovanja aditiva i metode za utvrđivanje njihove djelotvornosti. Dio pregleda obuhvaća rezultate sinteze i primjene vlastitih aditiva za naftu i plinski kondenzat. Posebno je opisan utjecaj kemijske strukture i molekulske mase polimernih aditiva te njihove koncentracije na tecivost i viskoznost. Ispitivanja su provedena na uzorcima nafte s naftnih polja u INI, Števkovica, Obod i Đeletovci i plinsko-kondenzatnih polja Molve, Kalinovac, Stari Gradac i Gola te mađarskog polja Barcs. Rezultati pokazuju da na djelotvornost u primjeni bitno utječu vrste
aditiva i nafte, odnosno plinskog kondenzata. Optimalni su rezultati postignuti primjenom aditiva na osnovi kopolimera dugolančanih estera metakrilne kiseline s vinil-karboksilnim kiselinama.
Vapor-liquid equilibrium data were measured isothermally in the near-azeotropic region of the 2-methylpropan-2-ol + water + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide system at ...333.15, 343.15, and 353.15 K. The data were processed using a recently developed method based on a small number of experiments that provides a complete thermodynamic description of the azeotropic behavior. The parameters of the third-order Redlich-Kister equation were correlated with the ionic liquid concentration to determine an analytical dependence of both the azeotropic composition and the pressure. Keywords alcohol-water system, azeotropy, correlation, ionic liquid, vapor-liquid equilibrium
U radu je opisan utjecaj dicikloheksiluree (DCU) i diizopropiluree (DiPrU), u bočnom lancu monomera na osnovi (met)akrilata, na kopolimerizaciju sa stirenom (St) i α-metilstirenom (α-MeSt), toplinsku ...stabilnost i mehanizam razgradnje priređenih kopolimera. Polimerizacija je provedena s dibenzoil-peroksidom (Bz2O2) u butanonu ili dioksanu pri 70 °C, do niske konverzije. Rezultati pokazuju izrazite razlike u početnoj brzini polimerizacije i svojstvima polimera akrilatnih i metakrilatnih monomera u ovisnosti o supstituentu u bočnom lancu. Dok N-akril-N,N--dicikloheksilurea (A-DCU) lako homopolimerizira i kopolimerizira sa St-om i α-MeSt-om, N-metakril-N,N-dicikloheksilurea (MA-DCU) ne homopolimerizira niti kopolimerizira s α-MeSt-om, ali kopolimerizira sa St-om iako sporije nego odgovarajući akrilni monomer. Rezultati istraživanja pokazuju da uvođenje diizopropiluree umjesto dicikloheksiluree u metakrilatnom monomeru također utječe na početnu brzinu polimerizacije. Naime, N-(met)akril-N,N--diizopropilurea (MA-DiPrU) ne homopolimerizira niti kopolimerizira s α-MeSt-om. Polimerizacija sa St-om je sporija u usporedbi s odgovarajućim monomerom koji sadrži DCU. Kopolimerizacija je statistička reakcija u kojoj je, neovisno o sastavu smjese komonomera, uvijek veći udjel St-a u kopolimeru. Toplinsko ponašanje svih polimera u osnovi je slično. Zagrijavanjem pri temperaturama od 100 °C - 450 °C razgrađuju se dvostupnjevitim mehanizmom. U prvom stupnju pri temperaturama od 180 °C - 250 °C dolazi do izdvajanja cikloheksilizocijanata (C6H11NCO), odnosno izopropilizocijanata (C3H7NCO). Čvrsti ostaci identificirani su kao kopolimeri N-(met)akril-cikloheksilamida (A-CHA, MA-CHA), odnosno N-(met)akril-izopropilamida (MA-iPrA) sa St-om ili α-MeSt-om. Stabilni su do 280 °C, a zatim se u jednom stupnju razgrađuju pri temperaturama od 280 °C - 450 °C.
Description of phase behaviour of a highly nonideal system mineral oil + DMF is a rather complex task, because hydrocarbon feed, which has to be separated into aromatic and nonaromatic fractions, ...consists of large number of compounds that differ significantly in molecular weight and chemical structure. Such a complex mixture was substituted by two pseudo-components, aromatic and nonaromatic in order to simplify the procedure. They were represented by adequate model compounds, whose thermodynamic behaviour was similar to the original one. The chosen model system simulates properly the real one in the sense of the mutual solubility of aromatic and nonaromatic components. However, this simplification of description of strongly nonideal mixtures should be considered as the first approximation.
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