In the present work, a hydrogen‐free one‐step catalytic fractionation of woody biomass using commercial β‐zeolite as catalyst in a flow‐through reactor was carried out. Birch, spruce, and walnut shells were compared as lignocellulosic feedstocks. β‐Zeolite acted as a bifunctional catalyst, preventing lignin repolymerization due to its size‐selective properties and also cleaving β‐O‐4 lignin intralinkages while stabilizing reactive intermediates. A rate‐limiting step analysis using different reactor configurations revealed a mixed regime where the rates of both solvolytic delignification and zeolite‐catalyzed depolymerization and dehydration affected the net rate of aromatic monomer production. Oxalic acid co‐feeding was found to enhance monomer production at moderate concentrations by improving solvolysis, while it caused structural changes to the zeolite and led to lower monomer yields at higher concentrations. Zeolite stability was assessed through catalyst recycling and characterization. Main catalyst deactivation mechanisms were found to be coking and leaching, leading to widening of the pores and decrease of zeolite acidity, respectively.

Microreactors present innovative solutions for problems pertaining to conventional reactors and therefore have seen successful application in several industrial processes. Yet, its application in heterogeneously catalyzed gas–liquid reactions has been challenging, mainly due to the lack of an easy and flexible methodology for catalyst incorporation inside these reactors. Herein, we report a facile technique for obtaining small (<2 nm) and well-distributed catalytic nanoparticles on the walls of silica-coated capillaries, that act as micro(channel) reactors. These particles are formed in situ on the reactor walls using polyelectrolyte multilayers (PEMs), built by layer-by-layer self-assembly. Manipulating the PEMs’ synthesis condition gives easy control over metal loading, without compromising on particle size. Both monometallic (Au and Pd) and bimetallic (AuPd) nanoparticles were successfully obtained using this technique. Finally, these catalytic microreactors were found to exhibit exceptional activity for the direct synthesis of hydrogen peroxide from H₂ and O₂.

This study demonstrates the use of a milireactor as intensified technology for the continuous production of furfural via acid dehydration of xylose in a bi-phasic media. Very rapid extraction of furfural, aided by fast mass transfer rates, is key to prevent furfural subsequent degradation. Thus, by operating at elevated temperatures (i.e., 150-190 ^οC), it is possible to maintain high furfural selectivity (ca. 70%) at high xylose conversion (ca. 80%) and very short residence times (up to 2.5 min). A reaction mechanism is proposed based on the observed conversion-selectivity trends, and on the analysis of product distribution. The contribution of humins to the carbon balance is remarkably low due to the high furfural extraction rates achieved in the millireactor. Through first-principle reactor modeling, we further demonstrate the potential of combining intensified reactor technologies with the extractive synthesis of furfural, and we show that solvent optimization will be crucial to boost furfural selectivity above 80%.