Measurement of molecular diffusion coefficients in supercritical carbon dioxide using a coated capillary column

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00041a029· OSTI ID:6493059

Lai, C C; Tan, C S ^[1]

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1. National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering

Molecular diffusion coefficients of ethyl acetate, toluene, phenol, and caffeine in supercritical carbon dioxide were measured by a chromatographic peak broadening technique in a coated capillary column at temperatures of 308, 318, and 328 K and pressures up to 145 bar. A linear adsorption in the polymer layer coated on the inner wall of the capillary column was observed. The experimentally determined diffusion coefficients showed substantial agreement with those reported in the literature. The diffusion coefficients were in the order of 10[sup [minus]4] cm[sup 2]/s and decreased with increasing carbon dioxide density. Based on the molecular diffusion coefficient data reported here and those published elsewhere, an empirically modified Wilke-Chang equation was proposed which was found to be more quantitative than some existing equations such as the Stokes-Einstein and Wilke-Chang equations.

• OSTI ID: 6493059
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 34:2; ISSN IECRED; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105* -- Separation Procedures
ACETATES
ADSORPTION ISOTHERMS
ALKYLATED AROMATICS
AROMATICS
CARBOXYLIC ACID SALTS
DIFFUSION
EXTRACTION
EXTRACTION APPARATUSES
EXTRACTION COLUMNS
HYDROCARBONS
HYDROXY COMPOUNDS
ISOTHERMS
MASS TRANSFER
MATHEMATICAL MODELS
ORGANIC COMPOUNDS
PHENOL
PHENOLS
SEPARATION EQUIPMENT
SEPARATION PROCESSES
SOLVENT EXTRACTION
SUPERCRITICAL GAS EXTRACTION
TOLUENE