Transesterification reactions can use alcohol, such as methanol and ethanol, catalysts, for example acid catalysts such as sulfonic and sulfuric acids, various metallic compounds, for example metallic salts such as titanium, zinc, magnesium, tin, antimony or lead salts. The metallic compounds also can be used in form of alcoholates, alkyl derivatives or oxides. Due to the high reactivity of basic catalysts, such as NaOH, KOH or LiOH, use of such catalysts is preferred in a methanol solution.
Transesterification reactions are generally carried out in a single catalysis stage in the case of a batch reaction or in two catalysis stages in the case of a continuous operation using overflow reactors. However, two-stage transesterification reactions include high residence times, for example 1-10 minutes to several hours for the first transesterification reaction and 1-10 minutes to several hours for the second transesterification reaction, while the separation step is static and requires settling time further increasing the process cycle time. Still further, single-stage reactions suffer from lower yields and can require high residence times. Despite the plentiful art, there exists a need for an efficient, cost-effective transesterification apparatus and process that provides high yield and short residence.