Microwave-Assisted Furfural Production Using Hectorites and Fluorohectorites as Catalysts

Abstract

It has previously been reported that the use of microwave heating, together with the presence of co-solvents, improves the efficiency of furfural production from biomass. Solid acid catalysts can be a good alternative to mineral acids, since they can prevent corrosion and can be reused. However, the formation of humines should be minimized. Several delaminated and fluorinated hectorites, with different types and strengths of acid sites, were synthesized and tested as catalysts for the production of furfural from commercial xylose and from an acid biomass extract of almond shells. A new methodology was developed to prepare crystalline fluorohectorite at 800 • C in just 3 h. The presence of F significantly increased the acidity strength in the protonated fluorohectorite (H-FH) taking into account its high ammonia desorption temperature (721 • C). Additionally, this sample had fourteen times higher total acidity by m 2 than the reference H-βeta acid catalyst. H-FH was the most efficient catalyst at short reaction times (1 h) for the transformation of xylose to furfural under microwaves using toluene as co-solvent, regardless of whether the xylose was commercial (20% furfural yield) or an extract of almond shells (60% furfural yield). However, the acidity of the extract affected the fluorohectorite structure and composition.

Polyaromatic Group Embedded Cd(II)-Coordination Polymers for Microwave-Assisted Solvent-Free Strecker-Type Cyanation of Acetals

“…In the last few years, the use of microwave (MW) irradiation in catalysis has developed markedly due to its possible significant advantages, such as shorter reaction time and higher product yield, over traditional heating [ 30 ]. Thus, various research groups (including ours) performed different catalytic reactions by using MW irradiation [ 31 , 32 , 33 , 34 , 35 ]. Thus, we have also tested the catalytic activities of our newly synthesized CPs as heterogeneous catalysts for the Strecker-type cyanation reaction of various acetals with trimethylsilyl cyanide (TMSCN) in solvent-free conditions under microwave irradiation ( Scheme 2 ).…”

“…Moreover, there is an ever-growing need for an alternate energy source which will be cost effective as well as environmentally friendly and highly efficient. Various research groups including ours are employing this technique to perform numerous catalytic reactions under homo- and heterogenous conditions [ 31 , 32 , 33 ]. Even though catalytic activities of various CPs have been discovered under MW conditions [ 34 , 35 ], the microwave-assisted cyanation of acetals catalyzed by CPs has not yet been significantly studied.…”

Editorial Catalysts: Special Issue on “Microwave-Assisted Catalysis”

“…The third paper of this issue, entitled "Microwave-Assisted Furfural Production Using Hectorites and Fluorohectorites as Catalysts" by Cesteros et al [7], can be considered strategic for developing processes directed to furfural production from renewable lignocellulosic biomass using microwaves during reactions. Furfural is an important building block in the chemical industry, since it can be applied for the synthesis of an important number of chemical products of interest.…”