2003 Volume 29 Issue 4 Pages 568-571
The effective diffusion coefficient (Deff) and partition coefficient (P) of fatty acids and alcohols with carbon numbers of 4 to 14 as substrates of an enzyme reaction were measured in di-2-ethylhexyl sodium sulfosuccinate (AOT)-gelatin combination microemulsion-based organogels (MBGs). The correlation equations between the effective diffusion coefficient and the molar volume of substrate (υ) were obtained as follows:
for fatty acid: Deff[10-10m2s-1] = 6.55×10-12υ-0.43
(109.0≤;υ[10-6m3mol-1]≤331.0)
for alcohol: DeffAL[10-10m2s-1] = 2.67×10-13υ-0.71
(103.6≤υ[10-6m3mol-1]≤325.6)
The partition coefficient of substrate, the molar ratio of MBG phase to bulk organic phase, decreased with increasing carbon number of substrate and remained almost constant at a carbon number of 8 or above as follows: PFA = 2.03 (butanoic acid), 1.17 (hexanoic acid), ca. 0.85 (octanoic acid, decanoic acid, dodecanoic acid and tetradecanoic acid); PAL = 4.01 (butanol), 1.70 (hexanol), ca. 1.50 (octanol, decanol, dodecanol and tetradecanol). The partition coefficients of alcohols were about 2-fold higher than those of fatty acids.
