Prediction of binary-liquid system viscosity from vapor-liquid equilibria data

Author

Eugene Henry Okrent, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

9-30-1960

Degree Name

Master of Science in Chemical Engineering - (M.S.)

Department

Chemical Engineering

First Advisor

Joseph Joffe

Second Advisor

C. L. Mantell

Third Advisor

George C. Keeffe

Abstract

This paper reviews the proposed methods for prediction of binary mixture viscosity. A calculation method is developed which predicts the binary liquid mixture viscosity of non-ideal systems of organic materials. The calculation method is an extension of the statistical mechanically derived equation:

η_m = Nh/V exp[χ₁Δ_G1⁺⁺ + χ₂ΔG₂⁺⁺ -ΔG^?/κ vap]/RT

A method has been developed for establishing the value of (ΔG^E/RT)vap from the constants of the Margules equation, which is an improvement over previous methods. The proposed equation is:

Log η_m = χ₁ log η₁ + χ₂ log η₂ – χ₁ χ₂/κ [(A_m+B_m/2) + (B_m-A_m/2)(χ₁-χ₂)]

The value of κ based upon the "hole theory" of liquids is 2.00; Eyring and his associates found an average value of κ = 2.45. For systems with positive κ values, the average value of κ was 2.77. However, a number of systems yielded negative κ values. These calculations demonstrate that κ is not a constant, independent of the system, but rather is dependent upon the electronic orientation and hydrogen bonding tendencies of the solute and solvent. Using the proper value of κ, estimated from viscosity data, predicted viscosities are within 3% of the observed values for systems with positive values of κ. If a larger error can be tolerated, an average κ value may be used, since the solvent, solute structure causes a greater variation in κ than do small changes in temperature. An estimate of K at one temperature in a given system may be used in calculating the viscosities at another temperature more accurately than the 2.45 or 2.77 average value of κ.

The proposed equation fails to predict the viscosities of associated systems of aqueous non-electrolytes.

Recommended Citation

Okrent, Eugene Henry, "Prediction of binary-liquid system viscosity from vapor-liquid equilibria data" (1960). Theses. 3030.
https://digitalcommons.njit.edu/theses/3030