Esterification of tall oil fatty acids by neutral components, such as stearyl alcohol and sterols, is an undesired reaction; a potential solution is to eliminate the neutral components by a competing esterification with short-chain carboxylic acids. Esterification of fatty acids and short-chain carboxylic acids with stearyl alcohol and sterols was studied in a laboratory-scale glass reactor in the temperature range of 60-140 degrees C. Linoleic acid (LA) was used as a model component for fatty acid esterification with stearyl alcohol (StOH) and sitosterol (SitOH). Linoleic acid underwent esterification with stearyl alcohol and sitosterol. In the presence of short-chain carboxylic acids, such as formic and acetic acid, the esterification of linoleic acid by stearyl alcohol was efficiently suppressed because stearyl alcohol reacted with the short-chain carboxylic acid. Formic acid catalyzed the formation of dienes from sitosterol and campesterol. The esterification and dehydration processes were verified by gas chromatographic analysis and extensive kinetic studies. Mathematical models for esterification and dehydration were developed and successfully applied to a selected part of experimental data.