Orbey, H
Orbey, N
An empirical cubic equation of state(EOS) was obtained by truncating the virial expansion in reciprocal of molar volume after the third term. The constants of the EOS was generalized in terms of critical temperature, critical pressure and Pitzer's acentric factor. In pure component applications the EOS exhibited a performance comparable to Peng-Robinson (1976) EOS in the reduced temperature range of 0.5 to 1. The present EOS tends to predict better saturation liquid volumes at reduced temperatures below 0.8, and better estimations for second virial coefficient at high reduced temperatures. The EOS was successfully employed for vapor liquid equilibrium calculations for some mixtures of normal or slightly polar fluids with traditional one binary parameter mixing rule at moderately high pressures. At low reduced temperatures, where conventional one adjustable parameter applications of the cubic equations compare unfavorably with dual methods based on excess Gibbs energy functions for the liquid phase, a new two constant mixing rule introduced by Stryjek and Vera (1986) was employed for the present equation of state.
Chemical Engineering Communications


An empirical method for the second viral coefficients of non-standard fluids
Kis, Konrad; Orbey, Hasan (Elsevier BV, 1989-9)
A new empirical method is proposed for the extension of Pitzer-Curl type correlations of the second virial coefficient to non-standard fluids as define
A novel synthesis of optically active alpha-amino acids
Demir, Ayhan Sıtkı (Walter de Gruyter GmbH, 1997-01-01)
A new enantioselective synthesis of alpha- amino acids are described in which the key step is the enantioselective reduction of E, and Z furyl ketone oxime ethers with chiral boron complexes. The chirality of amino acid is fully controlled by appropriate choice of geometrical isomer of the oxime ether.
Orbey, H.; Orbey, N. (Informa UK Limited, 1989-3)
A data reduction technique is introduced for the evaluation of second virial coefficients of gases at subcritical temperatures. The method makes use of the vapor-liquid equilibrium data, i.e., temperature, saturation pressure, liquid and vapor molar volumes and can be used to obtain second virial coefficients of a wide variety of fluids including polar, associating and quantum gases. The calculated second virial coefficients are in good agreement with their counterparts from literature, which are obtained f...
A four parameter Pitzer-curl type correlatıon of second virial coefficients
Orbey, Hasan (Informa UK Limited, 1988-3)
The Pitzer-Curl ( 1957) correlation of second virial coefficients is slightly modified to accommodate high temperature data ( TT4 4.0) of He and H2 and extended successfully to “ nonstandard” fluids as defined by Tarakad and Danner (1977), by introducing a fourth parameter per compound. The new version improves results at the high temperature limit while it gives comparable results with the previous versions presented by Pitzer and Curl ( 1957) and Tsonopoulos ( 1974) at lower temperatures. The present appr...
A new method for processing of monazite and examination of the products by X-ray analysis
Kizilyalli, Meral; Welch, Alastair J. (Elsevier BV, 1987-1)
Sintering reactions of lanthanide orthophosphates with Na2CO3 gave the expected products (Na3PO4 and Ln2O3) with stoichiometric amounts of Na2CO3. When less than the theoretical amounts of Na2CO3 were used, two intermediate products eventually characterized by X-ray diffraction as Na3Ln(PO4)2 and Ln3PO7 were detected. Application of the sintering method to naturally occurring phosphates, particularly the mineral monazite, proved to be very successful. By using the optimum amount of Na2CO3 to form Na3Ln(PO4)...
Citation Formats
H. Orbey and N. Orbey, “AN EMPIRICAL VIRIAL-LIKE CUBIC EQUATION OF STATE FOR PHASE EQUILIBRIUM CALCULATIONS,” Chemical Engineering Communications, pp. 35–45, 1990, Accessed: 00, 2020. [Online]. Available: