Sulfonated covalent triazine-based frameworks as catalysts for the hydrolysis of cellobiose to glucose

Abstract

Covalent triazine-based frameworks (CTFs) were synthesized in large scale from various monomers. The materials were post-synthetically modified with acid functionalities via gas-phase sulfonation. Acid capacities of up to 0.83 mmol g À1 at sulfonation degrees of up to 10.7 mol% were achieved. SulfonatedCTFs exhibit high specific surface area and porosity as well as excellent thermal stability under aerobic conditions (>300 C). Successful functionalization was verified investigating catalytic activity in the acidcatalyzed hydrolysis of cellobiose to glucose at 150 C in H 2 O. Catalytic activity is mostly affected by porosity, indicating that mesoporosity is beneficial for hydrolysis of cellobiose. Like other sulfonated materials, S-CTFs show low stability under hydrothermal reaction conditions. Recycling of the catalyst is challenging and significant amounts of sulfur leached out of the materials. Nevertheless, gas-phase sulfonation opens a path to tailored solid acids for application in various reactions. S-CTFs form the basis for multi-functional catalysts, containing basic coordination sites for metal catalysts, tunable structural parameters and surface acidity within one sole system.

Playing with covalent triazine framework tiles for improved CO2 adsorption properties and catalytic performance

“…Synthesis of CTF1 – 5. CTF materials have been synthesized via ionothermal synthesis in quartz glass ampules according to literature procedures [22]. In a general procedure, CTF1 – 3 were prepared as follows: 3 g of the selected monomer ( I , II or III ) were thoroughly mixed and finely ground with 5 equiv of ZnCl 2 within a glovebox and transferred into a quartz ampule (12 cm height and 3 cm diameter).…”

“…Gas adsorption measurements. In a similar manner as described before [22], nitrogen physisorption experiments were conducted on a Micromeritics ASAP 2010 instrument. Samples were degassed for at least 15 h at 150 °C using a FloVacDegasser.…”

“…Under ionothermal conditions, in molten zinc chloride, the rational combination of dicyano-substituted organic moieties can be used to provide stable carbon nanomaterials with diverse morphologies (i.e., porosity and specific surface area) along with variable chemical composition (i.e., content and type of light elements such as N, S and O) [14–15]. Major application fields of CTFs are represented by energy storage and conversion [16–18], gas storage and separation (e.g., H 2 , CO 2 and CH 4 ) [19–21] as well as various catalytic uses [22–30].…”

Effective hydrolysis of polysaccharides by activated attapulgite

“…As for starch as substrate, the hydrolysis rate was lower than that of inulin, which is not only related to the degree of polymerization, but also to the type of glycosidic bond; for that, the β (2–1) glycosidic bond of inulin is considered to be easier to hydrolyze than the α (1–4) glycosidic bond of starch 1,42,43 . The hydrolysis ratio remained unchanged in the later stage and this may be due to the pores of the catalyst being blocked by adsorbing of substrate/product with reaction time prolongation, resulting in the hydrolysis ratio not changing 41 . The above results show that ATP‐S has good catalytic activity in hydrolysis reactions under water solution, and the generated monomers are quite stable in this mild system.…”

“…However, the hydrolysis ratios of xylan, maltose, and cellobiose did not change in the later stage of the experiments; this may be because the average pore diameter of the catalyst is 3.178 nm, which is easily blocked by adsorbing of substrate/product with reaction time prolongation, resulting the hydrolysis ratio not changing. 41 From the data described above, it can be concluded that hydrolysis efficiency depends not only on the type of bond but also on the polymerization degree of the reactant.…”