A General Route of Using Lignite Depolymerized Derivatives for Catalyst Construction: Insights into the Effects of the Derivative Structures and Solvents

Abstract

Depolymerization is an emerging and promising route for the value-added utilization of low-rank coal (LRC) resources, and how to use the complex depolymerized mixtures efficiently is of great importance for this route. In this work, we designed the rational route of using depolymerized mixtures from lignite via ruthenium ion-catalyzed oxidation (RICO) depolymerization directly without complex separation to construct a Zr-based hydrogenation catalyst. The prepared catalyst was applied into the catalytic transfer hydrogenation of biomass-derived carbonyl compounds. Meanwhile, a copper-based oxidation catalyst was also constructed via a similar route to investigate the universality of the proposed route. Special insights were given into how the depolymerized components with different structures influenced the performances of the catalysts. The effects of the solvents used during the catalyst preparation (H 2 O and DMF) were also studied. The results showed that the proposed route using the depolymerized mixtures from lignite via RICO to construct catalysts was feasible for both Zr-based and Cu-based catalysts. The two catalysts prepared gave high efficiency for their corresponding reaction, i.e. , the Zr-based catalyst for catalytic transfer hydrogenation of biomass-derived carbonyl compounds and the Cu-based catalyst for selective oxidation of alcohols into aldehydes. Different depolymerized components contributed differently to the activity of the catalyst, and the solvents during the preparation process could also influence the activity of the catalyst. The depolymerized components and the solvents influenced the activities of the Zr-based catalyst mainly via changing the Zr contents, the microenvironment of Zr 4+ , and the specific areas of the catalyst.

Value-Added Products From Soil, Brown Coal, and Composted City Solid Waste

“…A very recent report in 2021 from China describes the use of Zr-HA and Cu-HA catalysts (Hao et al, 2021). The former zirconium-based compound has been demonstrated as a suitable reusable catalyst for carrying out the reduction of organic substrates, while the latter copper-containing compound is useful for oxidation.…”

“…These include making humic substance-based solar cells (Rohit et al, 2016). Based on reverse polymerization of humic substances, zirconium-humic acid (Zr-HA) and copper-humic acid (Cu-HA) catalysts, respectively for reduction and oxidation processes, have been developed recently (Hao et al, 2021) 1 . However, in these pandemic times, what catches attention most is the antiviral activity, in particular the reported anti-HIV-AIDS activity of humic substances (Zhernov et al, 2020), which has been shown to be superior to Himalayan Shilajit, an immune booster available from Dabur Co., Ghaziabad, India 2 .…”

Strong Oxophilicity of Zr Species in Zr4+-Exchanged Montmorillonite Boosted Meerwein–Ponndorf–Verley Reduction of Renewable Carbonyl Compounds

“…Meerwein–Ponndorf–Verley (MPV) reduction, which employs suitable alcohols as the hydrogen resources, is a feasible strategy to achieve chemoselective hydrogenation of carbonyl groups. Generally, MPV reduction of carbonyl groups can be promoted by Al-, − Sn-, , Hf-, − or Zr-based catalysts, − which have lower hydrogenation activity on other reducible groups, thus making MPV reduction highly selective on carbonyl groups. Among various catalysts, Zr-based catalysts (i.e., inorganic materials and organic–inorganic hybrids) are the most used class for MPV reduction of carbonyl groups.…”

A novel and highly efficient Zr-containing catalyst supported by biomass-derived sodium carboxymethyl cellulose for hydrogenation of furfural

“…Metal ion-organic ligand hybrid MPV catalysts are commonly used for the MPV reduction of furfural. The Zr-based catalysts such as UiO-66 (Qiu et al, 2020), Zr-DM (Hao et al, 2021), Zr-HAs (Sha et al, 2017), Zr-RSL (Hao et al, 2019) and Zr/Fe (Gu et al, 2020) showed good catalytic activity in the catalytic hydrogenation reaction using alcohols as hydrogen donors. The selection of ligands is important for the construction of metal ion-organic ligand hybrid MPV catalysts.…”

“…Besides the pure organic carboxylic acids, the natural macromolecules rich in organic carboxylic groups are also used in the construction of the MPV catalysts. In our previous work, the lignite derived humic acids and even lignite were used to construct Zr-containing MPV catalysts, and the prepared catalysts were proved to be highly efficient for the MPV reduction of various carbonyl compounds (Sha et al, 2017;Hao et al, 2019;Hao et al, 2021). Natural compounds rich in acidic carboxyl functional groups are natural functional molecules widely existing in nature (Luo et al, 2015).…”