Catalytic hydrotreatment of Alcell lignin fractions using a Ru/C catalyst

We here report the catalytic hydrotreatment of three different Alcell lignin fractions using a Ru/C catalyst in a batch reactor set-up (400 °C, 4 h, 100 bar H2 intake, 5 wt% catalyst on lignin). The fractions, obtained by a solvent fractionation scheme from Alcell lignin, differ in composition and molecular weight. The resulting product oils were characterized by various techniques, such as GC-MS-FID, GC × GC-FID, GPC, and 13C-NMR, to gain insight into the relationship between the feed and product yield/composition on a molecular level. The lowest molecular weight fraction (Mw = 660 g mol-1) gave the highest product oil yield after catalytic hydrotreatment (>70 wt% on lignin fraction). The main differences in molecular composition for the product oils were observed and are related to the chemical structure of the different feed fractions and less on the molecular weight. The highest amounts of valuable alkylphenolics (8.4 wt% on intake) and aromatic compounds (4.2 wt% on intake) in the product oils were obtained with the lowest molecular weight fraction. This fraction also contained the highest amounts of aliphatic hydrocarbons after the hydrotreatment reaction (14.0 wt% on intake), which were primarily linked to the presence of extractives in the Alcell lignin feed, that accumulate in this low molecular weight fraction during solvent fractionation

Catalytic hydrotreatment of fast pyrolysis liquids in batch and continuous set-ups using a bimetallic Ni-Cu catalyst with a high metal content

In this paper, an experimental study on the hydrotreatment of fast pyrolysis liquids is reported in both batch and continuous set-ups using a novel bimetallic Ni-Cu based catalyst with high Ni loading (up to 50%) prepared by a sol-gel method. The experiments were carried out in a wide temperature range (80-410 degrees C) and at a hydrogen pressure between 100-200 bar to determine product properties and catalyst performance as a function of process conditions. To gain insight into the molecular transformations, the product oils were analysed by GC x GC, H-1-NMR and GPC and reveal that the sugar fraction is reactive in the low temperature range (300 degrees C). In addition, the organic acids are very persistent and reactivity was only observed above 350 degrees C. The results are rationalized using a reaction network involving competitive hydrogenation of reactive aldehydes and ketones of the sugar fraction of fast pyrolysis liquids and thermal polymerisation. In addition, relevant macro-properties of the product oils including flash point (30 to 80 degrees C), viscosity (0.06 to 0.93 Pa s) and TG residue

Biobased chemicals from lignin

Dalende ruwe olie reserves, de toenemende vraag naar energie en nadelige gevolgen voor het milieu hebben de zoektocht naar hernieuwbare bronnen voor energieopwekking, transport brandstoffen en petrochemische producten een sterke stimulans gegeven. De laatste 20 jaar zijn er grote doorbraken op het gebied van cellulose en hemicellulose omzetting naar koolstof gebaseerde transportbrandstoffen (bijvoorbeeld bio-ethanol en biodiesel) en biobased chemicaliën gerealiseerd. Echter de valorisatie van lignine, de derde na grootste component in houtachtige biomassa, staat nog in de kinderschoenen. Lignine bevat veel aromatische eenheden en kan dienen als een uitgangsmateriaal voor de productie van aromaten en gealkyleerde fenolen, belangrijke tussenproducten in de petrochemische industrie. In dit proefschrift wordt de zogenaamde katalytische waterstofbehandeling gebruikt om lignine (voornamelijk Alcell lignine) om te zetten naar laag moleculare aromaten en gealkyleerde fenolen. In dit proces wordt lignine behandeld bij hoge temperaturen (400 °C) en waterstof druk (100-200 bar) met of zonder een oplosmiddel en een geschikte heterogene katalysator. Een Ru-katalysator werd het meest geschikt gevonden voor met name de oplosmiddel vrije katalytische watestofbehandeling. De product eigenschappen werden gekwantificeerd met geavanceerde GCxGC technieken en daarnaast zijn moleculaire reactiepaden bepaald op basis van product samenstellingen en gerationaliseerd met behulp van een reactie netwerk

Catalytic Hydrotreatment of Alcell Lignin Using Supported Ru, Pd, and Cu Catalysts

A catalyst screening study on the catalytic hydrotreatment of Alcell lignin in a batch setup was performed using supported Ru (C, Al2O3,TiO2), Pd (C, Al2O3), and a Cu/ZrO2 catalyst with the objective to determine the best catalyst for high yields of biobased aromatics and alkylphenolics. Experiments were performed at 400 °C, 4 h reaction time and an initial hydrogen pressure of 100 bar. Best results were obtained with Ru/TiO2 and a lignin oil (78 wt % on lignin intake) with 9.1 wt % alkylphenolics, 2.5 wt % aromatics, and 3.5 wt % catechols on lignin intake were obtained. The reaction products were characterized using advanced GC×GC-FID and GC×GC-TOFMS techniques in combination with GPC, 13C NMR, and GC–MS-FID measurements. Systematic studies with the Ru/C catalysts using variable batch times (0–8 h, 400 °C, and an initial hydrogen pressure of 100 bar) gave insights in the reaction pathways occurring during the catalytic hydrotreatment and these include depolymerization, hydrogenation, hydrodeoxygenation, and dehydration reactions

Catalytic hydrotreatment of pyrolytic lignins to give alkylphenolics and aromatics using a supported Ru catalyst

The catalytic hydrotreatment of two pyrolytic lignins (pine and forestry residue), obtained from the corresponding fast pyrolysis oils, and organosolv Alcell lignin as a benchmark was explored in a batch set-up using Ru/C as the catalyst (400 degrees C, 4 h, 100 bar initial H-2 pressure). The highest lignin oil yield was obtained for forest residue pyrolytic lignin (> 75 wt% on intake). Advanced GCxGC techniques in combination with GPC and C-13-NMR measurements indicate that the lignin oils contain high amounts of interesting monomeric chemicals like alkylphenolics (up to 20.5 wt% on lignin feed intake) and aromatics (up to 14.1 wt% on lignin feed intake). These values are considerably higher than for Alcell lignin (6.6 wt% alkylphenolics and 9.7 wt% aromatics) and clearly indicate that pyrolytic lignins have potential to be used as feeds for the production of biobased phenolics and aromatics

Catalytic Hydrotreatment of Alcell Lignin Using Supported Ru, Pd, and Cu Catalysts

A catalyst screening study on the catalytic hydrotreatment of Alcell lignin in a batch setup was performed using supported Ru (C, Al₂O₃,TiO₂), Pd (C, Al₂O₃), and a Cu/ZrO₂ catalyst with the objective to determine the best catalyst for high yields of biobased aromatics and alkylphenolics. Experiments were performed at 400 °C, 4 h reaction time and an initial hydrogen pressure of 100 bar. Best results were obtained with Ru/TiO₂ and a lignin oil (78 wt % on lignin intake) with 9.1 wt % alkylphenolics, 2.5 wt % aromatics, and 3.5 wt % catechols on lignin intake were obtained. The reaction products were characterized using advanced GC×GC-FID and GC×GC-TOFMS techniques in combination with GPC, ¹³C NMR, and GC–MS-FID measurements. Systematic studies with the Ru/C catalysts using variable batch times (0–8 h, 400 °C, and an initial hydrogen pressure of 100 bar) gave insights in the reaction pathways occurring during the catalytic hydrotreatment and these include depolymerization, hydrogenation, hydrodeoxygenation, and dehydration reactions

Catalytic Hydrotreatment of Humins in Mixtures of Formic Acid/2-Propanol with Supported Ruthenium Catalysts

The catalytic hydrotreatment of humins, which are the solid byproducts from the conversion of C6 sugars (glucose, fructose) into 5-hydroxymethylfurfural (HMF) and levulinic acid (LA), by using supported ruthenium catalysts has been investigated. Reactions were carried out in a batch setup at elevated temperatures (400 °C) by using a hydrogen donor (formic acid (FA) in isopropanol (IPA) or hydrogen gas), with humins obtained from d-glucose. Humin conversions of up to 69 % were achieved with Ru/C and FA, whereas the performance for Ru on alumina was slightly poorer (59 % humin conversion). Humin oils were characterized by using a range of analytical techniques (GC, GC-MS, GCxGC, gel permeation chromatography) and were shown to consist of monomers, mainly alkyl phenolics (>45 % based on compounds detectable by GC) and higher oligomers. A reaction network for the reaction is proposed based on structural proposals for humins and the main reaction products