Author:

Keywords:

ALKYLBENZENES, biorefinery, catechol, Chemistry, Chemistry, Multidisciplinary, CONVERSION, DEALKYLATION, DEPOLYMERIZATION, Green & Sustainable Science & Technology, HYDROGENOLYSIS, lignin, LIGNOCELLULOSE FRACTIONATION, PHENOL, Physical Sciences, REDUCTIVE CATALYTIC FRACTIONATION, Science & Technology, Science & Technology - Other Topics, SHAPE SELECTIVITY, sustainable chemistry, TRANSFORMATION, zeolites, Biomass, Catalysis, Catechols, Lignin, Water, Zeolites, G0H0918N#54526903, 0301 Analytical Chemistry, 0399 Other Chemical Sciences, 0904 Chemical Engineering, General Chemistry, Organic Chemistry, 3403 Macromolecular and materials chemistry, 3405 Organic chemistry, 4004 Chemical engineering

Abstract:

A catalytic route is developed to synthesize bio-renewable catechol from softwood-derived lignin-first monomers. This process concept consists of two steps: 1) O-demethylation of 4-n-propylguaiacol (4-PG) over acidic beta zeolites in hot pressurized liquid water delivering 4-n-propylcatechol (4-PC); 2) gas-phase C-dealkylation of 4-PC providing catechol and propylene over acidic ZSM-5 zeolites in the presence of water. With large pore sized beta-19 zeolite as catalyst, 4-PC is formed with more than 93 % selectivity at nearly full conversion of 4-PG. The acid-catalyzed C-dealkylation over ZSM-5 zeolite with medium pore size gives a catechol yield of 75 %. Overall, around 70 % catechol yield is obtained from pure 4-PG, or 56 % when starting from crude 4-PG monomers obtained from softwood by lignin-first RCF biorefinery. The selective cleavage of functional groups from biobased platform molecules through a green and sustainable process highlights the potential to shift feedstock from fossil oil to biomass, providing drop ins for the chemicals industry.