@article { author = {Daneshvar, Nezameddin and Salavati, Hossein}, title = {Polymerization of Silica in Water-Effect of Ultrasonic Waves on Coagulation and Sedimentation}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {1-7}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10953}, abstract = {Polymerization rates of silica at various concentrations and pHs have been studied via nephelometry. The ability and potency of ultrasonic radiation on the coagulation process in aqueous samples with and without silica colloidal particles have been extensively investigated. Factors affecting the rate and filtration volume such as silica concentration, time of radiation, temperature, and frequency of radiation have also been studied. The results indicate that ultrasonic radiation has two folded effect: on the one hand it breaks down the large flocs and on the other it results in the flocculation of small particles. The above mentioned effects lead to a reduced uniformity coefficient for the filter beds made of such coagulated particles.}, keywords = {Silica polymerization,Silica colloidal particles,Ultrasonic Waves,Coagulation,sedimentation,Flocculation,Filtration rate,Nephelometry}, url = {https://ijcce.ac.ir/article_10953.html}, eprint = {} } @article { author = {Heravi, Majid}, title = {Base Catalyzed Cyclization and Isomerization of 3-Propargylmercapto-1, 2,4-Triazine to Thiazolo [3,2-b][1,2,4]-Triazines}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {8-11}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10954}, abstract = {Transformation of 3-propargylmercapto-6 methyl-1, 2,4-triazin- 5 (2H)- one (1; R=CH3) to 3,6- dimethyl-7H- thiazolo [3,2-b] [1, 2, 4] triazin -7- one (2) is performed under basic condition. The formation of (2) may be mainly due to the high reactivity of acetylenes towards nucleophiles and isomerization of the intermediate. }, keywords = {Cyclization,Isomerization,3-Propargylmercapto-1,2,4- triazine,Thiazolo [3,2-b][1,4]- triazine}, url = {https://ijcce.ac.ir/article_10954.html}, eprint = {} } @article { author = {Amini, Mihammad Kazem}, title = {Complexation of Hydronium Ion with Several Crown Ethers in Nitromethane Solution}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {12-18}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10955}, abstract = {The interaction between hydronium ion and several crown ethers was studied via conductometry in nitromethane at 25 °C and 1H-NMR techniques. The stabilities of the resulting 1:1 complexes were determined from the conductance data and found to vary in the order DC18C6 > 18C6 > DB30C10 > DB24C8 > DB18C6 > ~B15C5 > DB21C7. For the first time, evidences for the formation of a 2:1 sandwich complex between the smaller crown ethers (i. e. B15C5 and 18 crowns) and hydronium ion in solution were observed by monitoring the molar conductance of hydronium ion as a function of the ligand to cation mole conductance of hydronium ion as a function of the ligand to cation mole ratio. The 1H-NMR data support the existence of such 2:1 adduct in solution.}, keywords = {Hydronium ion,Crown ether,Nitromethane,Conductometry,NMR}, url = {https://ijcce.ac.ir/article_10955.html}, eprint = {} } @article { author = {Abedini Khorrami, Saeed and Gharib, Farrokh and Zare, Karim and Aghai, Hossein}, title = {Determination of the Stability Constant of Vanadium (V) with Alaine}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {19-24}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10956}, abstract = {Formation equilibria of dioxy vanadium (V) complex with alanine in acidic media (pH<2.3) has been investigated potentiometrically and spectrophotometrically. In this condition the 1:1 complex has the formula VO2Y, where Y¯ represent the fully dissociated aminocarboxylate anion. The stability constant of VO2Y was determined as log KVO2Y=11.32±0.35 at 25±0.1 °C and I=1 mol per liter of sodium perchlorate. The protonation constant of alanine was also determined poteniumetrically under above condition.}, keywords = {Stability constant,sodium meta vanadate,Alanine,Dioxy vanadium complexes,Vanadium aminocarboxylates}, url = {https://ijcce.ac.ir/article_10956.html}, eprint = {} } @article { author = {Zafarani Moattar, Mohamad Taghi and Mirhoseni, Abdorreza}, title = {Isobaric vapor-Liquid Equilibrium of Ethyl-Acetate+ 2-Propanol and Ethyl Acetate+ Ethanol Mixtures at 84.8 kPa}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {25-28}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10957}, abstract = {Accurate vapor-liquid equilibrium data have been obtained for ethyl acetate + 2-propanol and ethyl acetate + ethanol mixtures at 84.8 kPa, and the results are discussed thermodynamically. The vapor-liquid equilibrium data are correlated with redlich-Kister, Margules, Van-Laar and Ortega, equations the parameters and standard deviation of which are calculated and reported. The best correlation is found in the case of the Ortega's equation.}, keywords = {Vapor-Liquid Equilibrium,Azeotropes,Ethyl acetate-2-Propanol,Ethyl acetate-Ethanol}, url = {https://ijcce.ac.ir/article_10957.html}, eprint = {} } @article { author = {Sarafraz Yazdi, Ali and Stephen, W.I.}, title = {Comparative Gas Chromatography of Halides Using Different Substituted Phenylboronic Acids as Derivatizing Reagents}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {29-34}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10958}, abstract = {The GC of halides (chloride, bromide and iodide) using phenylboronic acid (PBA), 4-bromophenylboronic acid (BPBA), 3, 5 bis (trifluoromethyl) phenylboronic acid (FPBA) and 2,4- dichlorophenylboronic acid (CPBA) as derivatizing reagents are compared. The reactions are carried out in the presence of mercuric salts. The detection systems used are FID and ECD. The thermal analysis of the compounds are studied prior to GC to get an indication of the likely operating temperatures. The unsubtituted phenylboronic acid show better volatility and FID response, but substituted phenylboronic acids exhibit better responses using ECD system. Finally FPBA is examined for the possible use in quantitative determination of chloride, bromide and iodide using solvent extraction procedure and ECD detection system. Detection limits for chloride, bromide and iodide are reported in the range of 0.29-0.35 pg.}, keywords = {Halides,Substituted phenylboronic acid,Gas-Liquid-Chromatography,Derivatization}, url = {https://ijcce.ac.ir/article_10958.html}, eprint = {} } @article { author = {Modarress, Hamid and Eliassi, Ali}, title = {Polymer Gel-Liquid Equilibria Using Uniface-FV}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {35-42}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10959}, abstract = {Based on Gibbs-Duhem law and using UNIFAC-FV computer algorithm, the activity of polymer component in polymer-solvent systems is determined. The variation of activity of components with concentration at different temperatures are used to find the equilibrium concentration, UCST, and LCST for the systems. Also by generalization of the method, Gel-Liquid equilibrium is studied in some three component systems: polymer-solvent-solvent..}, keywords = {Uniface,Uniface-FV,Group contribution,Polymer solution,Phase equilibria,Activity}, url = {https://ijcce.ac.ir/article_10959.html}, eprint = {} } @article { author = {Edalat, Mohsen and Bozorgmehri Boozarjomehry, Ramin and Basiri Parsa, Jalal}, title = {A Correlation for the Prediction of the Adiabatic Joule-Thomson Coefficient of Pure Gases and Gas Mixtures}, journal = {Iranian Journal of Chemistry and Chemical Engineering}, volume = {11}, number = {2}, pages = {43-49}, year = {1992}, publisher = {Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR}, issn = {1021-9986}, eissn = {}, doi = {10.30492/ijcce.1992.10960}, abstract = {A correlation based on the general form of cubic equations of state has been derived. This equation provides a convenient mathematical form of the Joule-Thomson coefficient in terms of the state variable V and T. The Joule-Thomson coefficient calculated by this correlation has been compared with experimental data. It has been shown that the Redilich-Kwang equation of state is a suitable equation for prediction of Jule-Thomson coefficient of non-hydrocarbon compounds. The joule-Thomson coefficient of light hydrocarbons can be obtained with greater accuracy through the use of the Soave-Redich-Kwang equation of state. As hydrocarbon compounds become heavier the Joule-Thomson coefficient correlation based on the Peng-Robinson equation of state gives more accurate results. In the superheat region and for simple and quantum compounds the Redlich-Kwang equation of state is superior. Because of the complexity of the Joule-Thomson coefficient the correlation obtained by the Lee-Kessler equation of state and based on the high average percent error resulting from this correlation, the Lee-Kessler equation of state is not recommended for prediction of the Joule-Thomson coefficient.}, keywords = {Joule-Thomson coefficient,Heat capacity Non-ideality,Mixing rules,Cubic equations,Lee-Kessler,Non-hydrocarbon}, url = {https://ijcce.ac.ir/article_10960.html}, eprint = {} }