They found that increased ester conversions could be obtained at increased
molar ratios of alcohol to oil, increased reaction temperatures, increased concentrations of sulfuric acid,
and longer reaction times. However, possible interaction of these variables was not investigated and optimal
conditions for the acid-catalyzed reaction were not recommended. The kinetics of the acid-catalyzed transesterification
with butanol were also investigated by Freedman et al. (1986).