Hydrotreatment of pyrolytic lignins to aromatics and phenolics using heterogeneous catalysts

Figueirêdo, Monique Bernardes; Jotic, Z.; Deuss, Peter J.; Venderbosch, R. H.; Heeres, Hero J.

doi:10.1016/j.fuproc.2019.02.020

Cited by 60 publications

(48 citation statements)

References 43 publications

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“…Moreover, after the recovery of low-molecular-weight compounds, a significant carbon-rich residue remains that also can be used as an energy carrier and feedstock for carbon materials 65 and can even be upgraded (though hydrotreatment) into additional phenolic compounds. 66 3.7.4. HSQC 2D NMR.…”

Section: Pyrolysis Liquid Compositionmentioning

confidence: 99%

Improving fast pyrolysis of lignin using three additives with different modes of action

et al. 2020

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Section: Pyrolysis Liquid Compositionmentioning

confidence: 99%

Improving fast pyrolysis of lignin using three additives with different modes of action

et al. 2020

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“…The main identified gaseous products were methane (CH 4 ), CO, CO 2 , and ethane (C 2 H 6 ), see Figure 5. In the case of direct lignin hydrotreatment (i.e., no O 3 entries), the small gas fraction produced (<8.5 wt% based on lignin intake) consisted mainly of CH 4 (from the hydrogenolysis of methoxy substituents present on the lignin structure and/or methanation reactions [77] ) and CO 2 (formed by acid-catalyzed decarboxylation reactions of reactive lignin fragments [20,78] ). The organosolv lignin yielded higher amounts of CH 4 , in line with its higher degree of methoxylation (vide supra, Table 1), as well as CO (which can be formed either by acidcatalyzed decarbonylation or subsequent chemistry in the gas phase, e.g., the reverse water-gas shift reaction [79] ).…”

Section: Gas Phase Compositionmentioning

confidence: 99%

A Two‐Step Approach for the Conversion of Technical Lignins to Biofuels

Figueirêdo

Venderbosch

Deuss

et al. 2020

Advanced Sustainable Systems

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strategies to valorize lignin are required. Depolymerization of lignin has been shown to have considerable potential, [6] leading to innovative lignin-derived biofuels [7,8] or drop-in chemicals. [9] In its native form, lignin consists of a highly crosslinked and methoxylated phenylpropanoid network. The structure of the biopolymer changes during isolation in typical (industrial) processes like the Kraft process used in the pulp and paper industry. [10] These technical lignins are currently produced at large scales (e.g., 50 million tons per year of Kraft lignin [11]) and consist of recalcitrant and remarkably complex structures as a result of their processing. Therefore, depolymerization is highly challenging. Various routes have been explored, and some examples are oxidative and reductive treatments using homogeneous and heterogeneous catalysts. [12] Catalytic hydrotreatment is a well-known reductive upgrading strategy for technical lignins. It involves treatment of lignin with molecular hydrogen (or a hydrogen donor) in the presence of a suitable catalyst. Upon this treatment, hydrodeoxygenation and hydrocracking reactions occur, and a range of valuable monomers can be obtained. [12,13] Interesting results have been reported using different setups, catalysts, reaction conditions, and lignin types (Table 1). Nonetheless, the harsh conditions that typically required cause competitive repolymerization that ultimately leads to char in addition to carbon losses to the gas phase. Altogether, these reactions have a negative impact on the techno-economic viability of the process. Furthermore, due to the presence of stable CC bonds in technical lignins, the yield and quality of the hydrotreated products are yet not optimal for such high end application. [14] Oxidation strategies have been also reported for lignin depolymerization, [12,33-35] from which ozonation stands as a relatively simple treatment for upgrading technical lignins. Ozone was shown to be highly reactive toward phenolic nuclei and CC double bonds at ambient conditions, and neither chemical additives nor catalysts are typically required. [36] It can be easily generated in situ either from oxygen or dry air, and such ozone generation technologies are industrially used [37,38] and thus wellestablished, safe, and available at all scales. Furthermore, ozone has a half-life of <1 h when dissolved, [39] thus any residual ozone in the system quickly decomposes to O 2 , providing an overall clean process with no need of extra separation steps. [40] Previous research has shown that the products obtained by ozonation Lignocellulose is a widely available carbon source and a promising feedstock for the production of advanced second-generation biofuels. Nonetheless, lignin, one of its major components, is largely underutilized and only considered an undesired byproduct. Through catalytic hydrotreatment, the highly condensed lignin can be partially depolymerized into a range of monomers. However, its recalcitrance and the presence of aromatic fragments linked by C...

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“…They also further demonstrated the milder activity of transition metals in a complementary study on Ni-based catalysts. 50 Figueiredo et al 51 observed that using a noblemetal-based catalyst, high monomer yields in the organic products could be obtained from the hydrodeoxygenation of pyrolytic lignin, also with a higher deoxygenation degree, in line with our results.…”

Section: ■ Resultsmentioning

confidence: 99%

In-Depth Analysis of Raw Bio-Oil and Its Hydrodeoxygenated Products for a Comprehensive Catalyst Performance Evaluation

Hita

Cordero-Lanzac

Kekäläinen

et al. 2020

ACS Sustainable Chem. Eng.

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Biomass pyrolysis liquids (bio-oils) unavoidably require catalytic hydrodeoxygenation (HDO) for their upgrading and stabilization for commercial usage. The complex composition of bio-oil constrains the fundamental kinetic understanding of the HDO. Here, we propose a multi-technique methodology to compositionally assess the complete spectrum of the HDO reactants and products, and then use it to pre-evaluate different catalysts in the HDO of a raw bio-oil obtained from black poplar. The used techniques are: micro chromatography (GC), GC with mass spectrometry (MS), bidimensional GC×GC/MS, elemental analysis, gel permeation chromatography, Karl-Fischer, thermogravimetric analysis, as well as Fourier ion cyclotron resonance mass spectrometry (FT-ICR/MS) using different ionization sources (ESI and APPI). The latter technique allows for the assessment of the heaviest and most refractory oxygenates in bio-oil, which have a pivotal role in the HDO catalyst performance. Three activated carbon-supported catalysts based on PtPd, NiW and CoMo mixed with a commercial HZSM-5 zeolite were used. We have been able to evaluate the multiple facets of catalyst performance: production of gases, catalytic coke, thermal lignin and most importantly, the aqueous and organic product fractions (hydrodeoxygenation of heavy species and production of light aromatics). The results of the detailed analysis methodology highlight their potential for the understanding of the HDO mechanism and for a detailed catalyst screening.

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Hydrotreatment of pyrolytic lignins to aromatics and phenolics using heterogeneous catalysts

Cited by 60 publications

References 43 publications

Improving fast pyrolysis of lignin using three additives with different modes of action

Improving fast pyrolysis of lignin using three additives with different modes of action

A Two‐Step Approach for the Conversion of Technical Lignins to Biofuels

In-Depth Analysis of Raw Bio-Oil and Its Hydrodeoxygenated Products for a Comprehensive Catalyst Performance Evaluation

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