Viscosity correlations of saturated fatty acids and their esters

Author

Thomas Joseph Redling, New Jersey Institute of Technology

Document Type

Thesis

Date of Award

6-30-1961

Degree Name

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

Department

Chemical Engineering

First Advisor

Saul I. Kreps

Second Advisor

Jerome J. Salamone

Third Advisor

Joseph Joffe

Abstract

Several correlations have been developed which permit calculation of the viscosities of the n-paraffin fatty acids and esters, beginning with formic and including stearic acid.

The correlations were obtained by interrelating the Log u and the Log P_v at the same temperature, where u is the viscosity in centipoise and P_v is the vapor pressure in millimeters Hg. A single line relationship represents all the fatty acids from propionic acid to and including stearic acid, while formic acid and acetic acid each have their own line. Methyl, ethyl, propyl and butyl formate can be represented by a single linear relationship, and the remaining esters, beginning with methyl acetate by another line.

The basic correlations take the form

Log u = A. +. B Log P_v

where A and B are constants typical for the series. These values were found to be ABAverage ErrorFormic Acid0.81437-0.3780.6%Acetic Acid0.39579-0.2820.8%Propionic to stearic Acids0.20560-0.2606.8%Formate Esters0.15209-0.2413.8Acetate to Stearate Esters0.06361-0.2255.0%

The relationships were further extended to include the simplified Antoine equation for vapor pressure, correlating the constants thereof to the number of carbon atoms in the compounds. The correlation of these constants with molecular size permits the calculation of vapor pressure of any member of the homologous series within the range of applicability from a knowledge of only the number of carbon atoms and the temperature, within a temperature range from the melting point to the normal boiling point, with an average error of 6.0 per cent. The equation for viscosity can now be expressed in terms of temperature and the number of carbon atoms. The final equations for determining viscosities at any temperature are as follows:

1) Formic Acid (average error = 0.6%)
u = 6.522/10 exp(2.709 - 535.9/t+230)

2) Acetic Acid (average error = 0.8%)
u = 2.488/10 exp(2.104 - 449.3/t+230)

3) Propionic Acid to Stearic Acid (average error . 6,8%)
u= 1,605/10 exp (2.041(10)^.00422C -222 +141(C)^.57/t+230)

4) Methyl, Ethyl, Propyl, and Butyl Formate (average error = 4.5%)
u = 1.419/10 exp (1.698(10)^.00417(C) - 223+25.2()^1.05/t+230)

5) Esters, beginning with the Acetates (average error . 5.0%)
u = 1.158/10 exp (1.585(10)^.00378(C)- 208 + 23.5(C) ^1.05/t+230)

Recommended Citation

Redling, Thomas Joseph, "Viscosity correlations of saturated fatty acids and their esters" (1961). Theses. 3234.
https://digitalcommons.njit.edu/theses/3234