Efficient production of p-hydroxybenzamide from poplar biomass


To explore a strategy for extracting p-hydroxybenzoate from biomass feedstocks (e.g., poplar and palm trees) and converting it into a portfolio of commodity chemicals including p-hydroxybenzamide, p-aminophenol, and paracetamol. 


Explored the impact of aqueous ammonia treatment conditions on the ratio of p-hydroxybenzoic acid to p-hydroxybenzamide in the aqueous waste stream.


The targeted product in the first processing stage is p-hydroxybenzamide produced from p-hydroxybenzoate esters found in the plant. A continuous reaction converts the p-hydroxybenzamide to p-aminophenol and recovers unreacted p-hydroxybenzamide. The p-aminophenol can then be acetylated to form paracetamol, which is isolated by liquid/liquid extraction at >95% purity and an overall p-hydroxybenzamide-to-paracetamol process yield of ~90%. The newly patented process uses water as the solvent, no chromatography, inexpensive reagents, no protecting groups, and scalable technology.


p-aminophenol has an estimated global market worth $1.4 billion. Paracetamol is one of the most abundantly produced pharmaceuticals in the world, valued at $130 million. Modifications  of  this  process  have  the  potential  to  produce  an array of chemical building blocks for the manufacturing materials and chemical products like plastics, surfactants, pigments, and pharmaceuticals.

Karlen, Steven D., et al. Production of biomass-derived p-hydroxybenzamide: Synthesis of p-aminophenol and paracetamol. ChemSusChem, n/a, e202400234. (n.d.) [DOI:10.1002/cssc.202400234]
Sustainable Biomass Conversion