Contribution to the study of biological products extraction of industrial interest

Abstract

Vanillin is an important building block for the chemical, pharmaceutical and food industries. It has the potential to become a key intermediate compound for the synthesis of bio-based polymers. Nowadays vanillin is mostly produced from petro-based resources as raw materials. This is not a sustainable situation, though, because of the nonrenewable nature of the resources employed. Therefore it would be desirable to produce it on an industrial scale from biomass (lignins). Currently, only 15% of vanillin is produced in this way, while the majority of lignins are usually burned for energy in the pulping process industry. Thus, the need for alternative solutions coming from the processing of the biomass feedstock is both a technological and economical priority. The petrochemical process is a mature process while the lignin process has yet to be improved before becoming a competitive one able to substitute the petrochemical route. The depolymerization of Kraft lignins is being heavily studied as a possible feedstock, following the biorefinery approach that considers lignins as high added value aromatic building blocks instead of being used as fuel for energy generation. The present work studies the efficiency of a standard Kraft lignin-derived vanillin extraction process that includes a liquid-liquid extraction unit operation. It also proposes three process design alternatives, one exclusive to the use of aliphatic alcohols C6-C8 as solvents, which have physical properties that can help to further simplify the process design. Simulations are performed in AspenPlus® V10 using both simplified and rigorous mathematical models. A solvent screening process for the liquid-liquid extraction step is also performed, following a literature research on suitable solvents both industrially used and theoretically suggested. Both resource requirements and toxicity related metrics are employed for the final solvent viability classification proposed.