Synthesis of Porous Clay Heterostructures Modified with SiO₂–ZrO₂ Nanoparticles for the Valorization of Furfural in One‐Pot Process

Abstract

The layered structure of two smectites (montmorillonite and saponite) are modified by the insertion of SiO2–ZrO2 nanoparticles, with a Si/Zr molar ratio of 5, to form porous clay heterostructures (PCHs). These PCHs exhibit a clear improvement of the textural and acid properties in comparison to the starting clays, due to the formation of a pillared structure and the presence of Zr species, which provide an increase in the amount of Lewis acid sites. These materials are studied in one‐pot catalytic processes to transform furfural into valuable products, such as furfuryl alcohol, alkyl furfuryl ethers, alkyl levulinates or γ‐valerolactone, depending on the experimental conditions. Thus, the use of milder reaction temperature (110 °C) favors the formation of furfuryl alcohol and alkyl furfuryl ethers, while higher temperatures (170 °C) promote the formation of alkyl levulinate and γ‐valerolactone, as well as an increase in nondetected products associated to the formation of humins due to the polymerization of furfural and/or furfuryl alcohol.

Nb-Based Catalysts for the Valorization of Furfural into Valuable Product through in One-Pot Reaction

“…In the next step, FOL is etherified with the alcohol, used as a solvent, to form IpFE, requiring Lewis or Brönsted acid sites [26]. In this sense, it has been reported that other catalysts, such as Zr-based catalysts or zeolites, do not stop the reaction in FOL or IpFE, evolving towards other consecutive products in the one-pot process, in such a way that the IpFE yield with these catalysts is relatively low in comparison to the catalysts reported in this study [22,26,57]. Thus, it can be concluded that the use of Nb-based catalysts would favor the formation of alkylfurfuryl ethers.…”

Nano-Silver-Coated Porous Clay Heterostructure Fillers for PLA and Biaxially Oriented Poly(lactic acid) Dielectric Films

“…The peaks at 1630 and 3450 cm –1 represented the Si–OH bending and stretching vibration of hydrogen bonds due to the absorption of water on the PCH′s surface. In addition, it was difficult to examine any band in the −OH stretching, attributed to the occurred dehydroxylation in a phyllosilicate due to the calcination of the organic contents at 600 °C . The FTIR spectra of Ag/PCHs corresponded to porous clay heterostructures.…”

“…In addition, it was difficult to examine any band in the −OH stretching, attributed to the occurred dehydroxylation in a phyllosilicate due to the calcination of the organic contents at 600 °C. 37 The FTIR spectra of Ag/PCHs corresponded to porous clay heterostructures. Moreover, there was no significant change in the chemical structure after coating the nano-silver on the porous clay heterostructure surface, and the increment of the contents of nano-silver did not affect the chemical structure of porous clay heterostructures.…”

Shrinkage Dynamics of Organic Template Substances with Long Alkyl Chains toward Porous Material Design

“…10 HDTMA + monomers with alkyl chains C n H 2n+1 with n of 12− 20, corresponding to the length of ∼2 nm, are often employed as templates for the synthesis of PCHs. 11 Optimization of the second process, pillaring by templates between nanosheets, could be straightforward for raising the productivity of mesopores as well as their sizes since the nanometer-sized templates are removed to be mesopore sites. The pillaring effect and relevant enhancement of mesoporosity together with mesopore sizes have been thus studied focusing on the layer charges of base clay, 5 the chain length of surfactant, 12 the content of base clay, 13 and so on.…”

“…Porous clay nanoheterostructures (PCHs) are promising mesoporous silica-based materials synthesized adopting the above templating schemes. , The organic template substances participate in synthesizing PCHs as follows: substitution of interlayer cations by bulky organic cations to be a template, an addition of silicon alkoxide hydrolyzed around the template, filtration, washing of the obtained gel, and finally calcination to remove the template . HDTMA + monomers with alkyl chains C n H 2 n +1 with n of 12–20, corresponding to the length of ∼2 nm, are often employed as templates for the synthesis of PCHs . Optimization of the second process, pillaring by templates between nanosheets, could be straightforward for raising the productivity of mesopores as well as their sizes since the nanometer-sized templates are removed to be mesopore sites.…”