The commonly used route to vanillin
is through catechol and guaiacol. Catechol is generally made from phenol.
This is a purely petrochemical route. Much work has been done, however,
on developing alternative routes from renewable feedstock.
Dr. Karen M. Draths and Professor John W. Frost of Michigan State University
received the Presidential Green Chemistry Challenge award in 1998 for
their work developing a range of synthetic routes from plant-derived
glucose. They used genetically modified bacteria, which operated in
aqueous solution at relatively low temperatures. The modified bacteria
produce catechol via two other intermediates.
The difference in conditions is clear if the two routes are compared.