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Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (31 March 2024) | Viewed by 8858

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Dr. Margarida M. Antunes

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Department of Chemistry, CICECO–Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
Interests: vegetable biomass; heterogeneous catalysis; multifunctional catalysts; hydrolysis; dehydration; catalytic transfer hydrogenation; one-pot reactions

Special Issue Information

Dear Colleagues,

The anthropogenic emissions caused by the use of fossil fuels prompt demand for sustainable renewable alternatives. Biomass plays an important role in mitigating climate change, as it is the most abundant renewable source of organic carbon available on Earth. It can be found in terrestrial agriculture, such as in forestry, food and other solid residues, or aquatic biomass, such as in the form of algae residues. The valorization of these residues is possible due to the components present therein, such as cellulose, hemicelluloses, lignin and starch. These components can be converted to important biofuels and chemicals, such as organic acids, furanic aldehydes, furanic ethers, levulinates, aromatics and amino acids with applications in several sectors of the chemical industry. Homogeneous catalysts can be very efficient in several conversion processes, but they present several drawbacks such as difficult recovery and separation from the target products, with increased costs. The use of multifunctional heterogenous catalysts is important to enhance the productivity of the processes and allow multiple steps to be carried out in only one reactor. Hence, the development of suitable heterogeneous catalysts for biomass valorization is crucial. This issue covers all aspects of heterogeneous catalysis applied to the valorization of vegetable biomass and derived compounds for producing useful chemicals, biofuels or fuel additives.

Dr. Margarida M. Antunes
Guest Editor

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Keywords

waste and biomass valorization
fuels
bioproducts
heterogeneous catalysts
hydrogenation
oxidation
condensation

Published Papers (7 papers)

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Research

22 pages, 1883 KiB

Open AccessArticle

The Autocatalytic Chemical Reaction of a Soluble Biopolymer Derived from Municipal Biowaste

by Elio Padoan, Enzo Montoneri, Andrea Baglieri, Francesco Contillo, Matteo Francavilla and Michéle Negre

Molecules 2024, 29(2), 485; https://doi.org/10.3390/molecules29020485 - 18 Jan 2024

Viewed by 606

Abstract

The paper discusses the perspectives of further implementation of the autocatalytic properties of a soluble biopolymer (SBP) derived from municipal biowastes for the realisation of a biorefinery producing value-added bio-products for consumer use. The reaction of an SBP and water is reported to cause the depolymerisation and oxidation of the pristine SBP organic matter with the formation of carboxyl-functionalised polymers having lower molecular weight and CO₂. These findings demonstrate the oxidation of the SBP via water, which could only occur through the production of O and OH radicals catalysed by the SBP. According to the adopted experimental plan, the anaerobic digestate supplied by an Italian municipal biowaste treatment plant was hydrolysed in pH 13 water at 60 °C. The dry product was re-dissolved in plain water at pH 10 and used as a control against the same solution with hydrogen peroxide at 0.1–3 H₂O₂ moles per SBP carbon mole added. The control and test solutions were kept at room temperature, in the dark or in a climatic chamber under irradiation with simulated solar light, until the pH of the solutions remained constant. Afterwards, the solutions were processed to recover and analyse the crude soluble products. The present work reports the results obtained for the control solution and for the test solutions treated in the presence and absence of H₂O₂, with and without pH control, in the dark and under irradiation with simulated solar light. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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21 pages, 1407 KiB

Open AccessArticle

Mild Chemical Treatment of Unsorted Urban Food Wastes

by Elio Padoan, Enzo Montoneri, Andrea Baglieri, Matteo Francavilla and Michèle Negre

Molecules 2023, 28(22), 7670; https://doi.org/10.3390/molecules28227670 - 20 Nov 2023

Cited by 2 | Viewed by 771

Abstract

Municipal biowastes are conventionally treated by assessed anaerobic and aerobic fermentation to produce biogas, anaerobic digestate, and compost. Low-temperature hydrolysis and the oxidation of the digestate and compost, which are still at the experimental stage, are known to yield water-soluble value-added chemical specialities for use in different sectors of the chemical industry and in agriculture. The present paper reports the application of the two chemical reactions to the biowastes before fermentation. The products obtained in this manner are compared with those obtained from the chemical reactions applied to the fermented biowastes. Based on the experimental results, the paper discusses the expected environmental and economic benefits of the above chemical processes and products in comparison with the products obtained by other known biotechnologies for the valorisation of biomass as a feedstock for the biobased chemical industry. The results point out that a sustainable biowaste-based refinery that produces biofuel and biobased chemicals may be developed by integrating chemical and fermentation technologies. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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18 pages, 10019 KiB

Open AccessArticle

Conversion of Similar Xenochemicals to Dissimilar Products: Exploiting Competing Reactions in Whole-Cell Catalysis

by Francesca Sannelli, Nikoline Corell Sindahl, Stefan S. Warthegau, Pernille Rose Jensen and Sebastian Meier

Molecules 2023, 28(13), 5157; https://doi.org/10.3390/molecules28135157 - 1 Jul 2023

Viewed by 1121

Abstract

Many enzymes have latent activities that can be used in the conversion of non-natural reactants for novel organic conversions. A classic example is the conversion of benzaldehyde to a phenylacetyl carbinol, a precursor for ephedrine manufacture. It is often tacitly assumed that purified enzymes are more promising catalysts than whole cells, despite the lower cost and easier maintenance of the latter. Competing substrates inside the cell have been known to elicit currently hard-to-predict selectivities that are not easily measured inside the living cell. We employ NMR spectroscopic assays to rationally combine isomers for selective reactions in commercial S. cerevisiae. This approach uses internal competition between alternative pathways of aldehyde clearance in yeast, leading to altered selectivities compared to catalysis with the purified enzyme. In this manner, 4-fluorobenzyl alcohol and 2-fluorophenylacetyl carbinol can be formed with selectivities in the order of 90%. Modification of the cellular redox state can be used to tune product composition further. Hyperpolarized NMR shows that the cellular reaction and pathway usage are affected by the xenochemical. Overall, we find that the rational construction of ternary or more complex substrate mixtures can be used for in-cell NMR spectroscopy to optimize the upgrading of similar xenochemicals to dissimilar products with cheap whole-cell catalysts. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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17 pages, 15578 KiB

Open AccessArticle

Heterogenization of Heteropolyacid with Metal-Based Alumina Supports for the Guaiacol Gas-Phase Hydrodeoxygenation

by Rita F. Nunes, Daniel Costa, Ana M. Ferraria, Ana M. Botelho do Rego, Filipa Ribeiro, Ângela Martins and Auguste Fernandes

Molecules 2023, 28(5), 2245; https://doi.org/10.3390/molecules28052245 - 28 Feb 2023

Cited by 6 | Viewed by 1374

Abstract

Because of the global necessity to decrease CO₂ emissions, biomass-based fuels have become an interesting option to explore; although, bio-oils need to be upgraded, for example, by catalytic hydrodeoxygenation (HDO), to reduce oxygen content. This reaction generally requires bifunctional catalysts with both metal and acid sites. For that purpose, Pt-Al₂O₃ and Ni-Al₂O₃ catalysts containing heteropolyacids (HPA) were prepared. HPAs were added by two different methods: the impregnation of a H₃PW₁₂O₄₀ solution onto the support and a physical mixture of the support with Cs_2.5H_0.5PW₁₂O₄₀. The catalysts were characterized by powder X-ray diffraction, Infrared, UV-Vis, Raman, X-ray photoelectron spectroscopy and NH₃-TPD experiments. The presence of H₃PW₁₂O₄₀ was confirmed by Raman, UV-Vis and X-ray photoelectron spectroscopy, while the presence of Cs_2.5H_0.5PW₁₂O₄₀ was confirmed by all of the techniques. However, HPW was shown to strongly interact with the supports, especially in the case of Pt-Al₂O₃. These catalysts were tested in the HDO of guaiacol, at 300 °C, under H₂ and at atmospheric pressure. Ni-based catalysts led to higher conversion and selectivity to deoxygenated compound values, such as benzene. This is attributed to both a higher metal and acidic contents of these catalysts. Among all tested catalysts, HPW/Ni-Al₂O₃ was shown to be the most promising, although it suffered a more severe deactivation with time-on-stream. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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15 pages, 7600 KiB

Open AccessArticle

Hydration of Camphene over PW-SBA-15-SO₃H

by José Castanheiro

Molecules 2023, 28(1), 6; https://doi.org/10.3390/molecules28010006 - 20 Dec 2022

Viewed by 1142

Abstract

The hydration of camphene was carried out over SBA-15 with sulfonic acid groups and tungstophosphoric acid at 50 °C. The main product of camphene hydration was isoborneol, with camphene hydrate and borneol as byproducts. The catalytic activity increased with the amount of tungstophosforic acid (PW) immobilized on the silica support until a maximum, which was obtained with the PW4-SBA-15-SO₃H material (16.4 wt.%). When the amount of PW immobilized on SBA-15 increased (PW5-SBA-15-SO₃H, 21.2 wt.%), the catalytic activity decreased. The catalytic activity of PW4-SBA-15-SO₃H increased with the water content of the solvent, until a maximum was reached with 50% water. With higher water concentrations, a decrease in the catalytic activity was observed. The selectivity to isoborneol was 90% at 99% camphene conversion in the presence of the PW4-SBA-15-SO₃H catalyst. The catalytic stability of the PW4-SBA-15-SO₃H material during camphene hydration was studied by performing consecutive batch runs with the same catalyst sample. After the third run, a trend towards stabilized catalytic activity was observed. A kinetic model is also proposed. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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14 pages, 3719 KiB

Open AccessArticle

Sustainable Ketalization of Glycerol with Ethyl Levulinate Catalyzed by the Iron(III)-Based Metal-Organic Framework MIL-88A

by Massimo Melchiorre, Domenico Lentini, Maria Elena Cucciolito, Francesco Taddeo, Maryam Hmoudah, Martino Di Serio, Francesco Ruffo, Vincenzo Russo and Roberto Esposito

Molecules 2022, 27(21), 7229; https://doi.org/10.3390/molecules27217229 - 25 Oct 2022

Cited by 12 | Viewed by 1659

Abstract

The catalytic properties of a simple iron-containing MOF based on fumaric acid, MIL-88A, were investigated in the ketalization of ethyl levulinate with glycerol. The corresponding product is a component of current interest as a renewable building block for many uses. Under the following conditions (solventless, 120 °C, stoichiometric ratio, 1% cat.), the reaction proceeds with good yields (85%), and the catalyst can be recovered and recycled without loss of activity, despite some changes in the crystalline lattice and morphology. Moreover, the residual iron content in the product is in the order of units of ppm (≤2), which demonstrates the robustness of the MOF under the reaction conditions. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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9 pages, 1585 KiB

Open AccessArticle

Easy and Fast Production of Solketal from Glycerol Acetalization via Heteropolyacids

by Diana Julião, Fatima Mirante and Salete S. Balula

Molecules 2022, 27(19), 6573; https://doi.org/10.3390/molecules27196573 - 4 Oct 2022

Cited by 6 | Viewed by 1267

Abstract

This work presents an effective and fast procedure to valorize the main waste produced from the biodiesel industry, i.e., the glycerol. The acetalization of glycerol with acetone represents an effective strategy to produce the valuable solketal, a fuel additive component. In this work, the catalytic efficiency of different commercial heteropolyacids (HPAas) was compared under a solvent-free system. The HPAs used were H₃[PW₁₂O₄₀] (PW₁₂), H₃[PMo₁₂O₄₀] (PMo₁₂) and H₄[SiW₁₂O₄₀] (SiW₁₂). The influence of reactional parameters such as reactants stoichiometry, catalyst concentration and reaction temperature were investigated in order to optimize experimental conditions to increase cost-efficiency and sustainability. HPAs demonstrated to be highly efficient for this type of reaction, presenting a high and fast glycerol conversion, with high selectivity to solketal under sustainable conditions (solvent-free system and room temperature medium). The activity of HPAs using 3% to glycerol weight and a glycerol/acetone ratio of 1:15 followed the order: PW₁₂ (99.2%) > PMo₁₂ (91.4%) > SiW₁₂ (90.7%) as a result of the strong acidic sites after 5 min. In fact, only 5 min of reaction were needed to achieve 97% of solketal product in the presence of the PW₁₂ as a catalyst. This last system presents an effective, selective and sustainable catalytic system to valorize glycerol. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for the Valorization of Biomass Derived Compounds)

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