The solubilities of beta -carotene and capsaicin have been measured in supe
rcritical carbon dioxide and in difluoromethane (R-32) and 1,1,1,2-tetraflu
oroethane (R-134a) in the liquid phase at temperatures near and somewhat be
low their critical points. The solubility of beta -carotene was also measur
ed in 1,1,1-trifluoroethane (R-143a). The temperatures of the measurements
ranged from 35 degreesC to 55 degreesC for capsaicin (up to 85 degreesC in
R-32) and from 40 degreesC to 70 degreesC for beta -carotene. The solubilit
ies were determined using an HPLC system for capsaicin and a static high-pr
essure cell for beta -carotene, and the amounts of products extracted were
measured spectroscopically. At similar temperatures and densities, the solu
bility of capsaicin in the halocarbons was higher than that in carbon dioxi
de; there was not such a clear trend for beta -carotene. Where the data cov
ered a sufficient density range, they (along with literature data for the s
olutes in carbon dioxide) were analyzed with the semiempirical density-base
d model of Mendez-Santiago and Teja.