Hero J. Heeres

Hydroxymethylfurfural, A Versatile Platform Chemical Made from Renewable Resources

Renewable Resources Robert-Jan van Putten,†,‡ Jan C. van der Waal,† Ed de Jong,*,† Carolus B. Rasrendra,‡,⊥ Hero J. Heeres,*,‡ and Johannes G. de Vries* †Avantium Chemicals, Zekeringstraat 29, 1014 BV Amsterdam, the Netherlands ‡Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands DSM Innovative Synthesis BV, P.O. Box 18, 6160 MD Geleen, the Netherlands Department of Chemical Engineering, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia

Caprolactam from renewable resources: catalytic conversion of 5-hydroxymethylfurfural into caprolactone

In zijn dissertatie beschrijft dhr. Teddy experimentele onderzoek naar de omzetting van 5-hydroxymethylfurfural (HMF) naar caprolactam, de uitgangsstof voor nylon 6. Het HMF kan op zijn beurt weer gemaakt worden uit lignocellulosische biomassa, zoals hout of grasachtig afval, is dan dus een groen basismateriaal. C6-suikers in lignocellulosische biomassa zijn interessante startmaterialen voor groene chemicalien met grote toepassingsmogelijkheden. HMF kan gemaakt worden uit D-fructose en mogelijk ook uit goedkopere suikers als D-glucose. Een grote uitdaging voor dit onderzoek betrof de ontwikkeling van katalytische routes voor de omzetting van HMF naar 1,6-hexanediol (1,6-HD). Vier verschillende routes zijn onderzocht: de directe hydrogenatie van HMF naar 1,6-HD, een tweestapsroute via 2,5-THF-dimethanol (THFDM), een driestapssynthese via THFDM en 1,2,6-hexanetriol (1,2,6-HT) en ten slotte een vierstapssynthese via THFDM, 1,2,6-HT en tetrahydro-2H-pyran-2-ylmethanol (2-THPM).

Formation, molecular structure, and morphology of humins in biomass conversion: influence of feedstock and processing conditions.

Neither the routes through which humin byproducts are formed, nor their molecular structure have yet been unequivocally established. A better understanding of the formation and physicochemical properties of humins, however, would aid in making biomass conversion processes more efficient. Here, an extensive multiple-technique-based study of the formation, molecular structure, and morphology of humins is presented as a function of sugar feed, the presence of additives (e.g., 1,2,4-trihydroxybenzene), and the applied processing conditions. Elemental analyses indicate that humins are formed through a dehydration pathway, with humin formation and levulinic acid yields strongly depending on the processing parameters. The addition of implied intermediates to the feedstocks showed that furan and phenol compounds formed during the acid-catalyzed dehydration of sugars are indeed included in the humin structure. IR spectra, sheared sum projections of solid-state 2DPASS (13) C NMR spectra, and pyrolysis GC-MS data indicate that humins consist of a furan-rich polymer network containing different oxygen functional groups. The structure is furthermore found to strongly depend on the type of feedstock. A model for the molecular structure of humins is proposed based on the data presented.

Chiral separation by enantioselective liquid-liquid extraction

The literature on enantioselective liquid-liquid extraction (ELLE) spans more than half a century of research. Nonetheless, a comprehensive overview has not appeared during the past few decades. Enantioselective liquid-liquid extraction is a technology of interest for a wide range of chemists and chemical engineers in the fields of fine chemicals, pharmaceuticals, agrochemicals, fragrances and foods. In this review the principles and advances of resolution through enantioselective liquid-liquid extraction are discussed, starting with an introduction on the principles of enantioselective liquid-liquid extraction including host-guest chemistry, extraction and phase transfer mechanisms, and multistage liquid-liquid extraction processing. Then the literature on enantioselective liquid-liquid extraction systems is reviewed, structured on extractant classes. The following extractant classes are considered: crown ether based extractants, metal complexes and metalloids, extractants based on tartrates, and a final section with all other types of chiral extractants.

Catalytic Conversion of Dihydroxyacetone to Lactic Acid Using Metal Salts in Water

We herein present a study on the application of homogeneous catalysts in the form of metal salts on the conversion of trioses, such as dihydroxyacetone (DHA), and glyceraldehyde (GLY) to lactic acid (LA) in water. A wide range of metal salts (26 in total) were examined. Al(III) salts were identified as the most promising and essentially quantitative LA yields (>90 mol%) were obtained at 140 °C and a reaction time of 90 min. A reaction pathway is proposed and a kinetic model using the power law approach was developed for the conversion of DHA to LA with pyruvaldehyde (PRV) as the intermediate. Good agreement between experimental data and the model was obtained. Model predictions, supported by experiments, indicate that a high yield of LA is favoured in dilute solutions of DHA (0.1 M) at elevated temperatures (180 °C) and reaction times less than 10 min.

Tunable and selective conversion of 5-HMF to 2,5-furandimethanol and 2,5-dimethylfuran over copper-doped porous metal oxides

Tunable and selective hydrogenation of the platform chemical 5-hydroxymethylfurfural into valuable C6 building blocks and liquid fuel additives is achieved with copper-doped porous metal oxides in ethanol. A new catalyst composition with improved hydrogenation/hydrogenolysis activity is obtained by introducing small amounts of ruthenium dopant into the previously reported Cu(0.59) Mg2.34 Al1.00 structure. At a mild reaction temperature (100 °C), 2,5-furandimethanol is obtained with excellent selectivity up to >99%. Higher reaction temperatures (220 °C) favor selective deoxygenation to 2,5-dimethylfuran and minor product 2,5-dimethyltetrahydrofuran with a combined yield as high as 81%. Notably, these high product yields are maintained at a substrate concentration up to 10 wt% and a low catalyst loading. The influence of different alcohol solvents on product selectivity is explored. Furthermore, reaction intermediates formed at different reaction temperatures are identified. The composition of these product mixtures provides mechanistic insight into the nature of the reduction pathways that influence product selectivity. The catalysts are characterized by elemental analysis, TEM, and BET techniques before and after the reaction. Catalyst recycling experiments are conducted in batch and in a continuous-flow setup.

In situ catalytic pyrolysis of lignocellulose using alkali-modified amorphous silica alumina

Canadian pinewood was pyrolyzed at 450 °C in an Infrared oven and the pyrolysis vapors were converted by passing through a catalyst bed at 450 °C. The catalysts studied were amorphous silica alumina (ASA) containing alkali metal or alkaline earth metal species including Na, K, Cs, Mg and Ca. The catalysts effectiveness to reduce the bio-oil oxygen content, to enhance the bio-oil energy density and to change the liquid and gas product distribution were evaluated using different techniques including gravimetric analysis, elemental analysis, Karl-Fischer titration, GC/MS and micro-GC analysis. According to the results K/ASA found to be the most effective catalysts for conversion of hollocellulose (hemicellulose and cellulose)-derived vapors of pinewood while Cs/ASA catalyst was the most effective catalyst for conversion of lignin-derived vapors and production of hydrocarbons.

Solvent free depolymerization of Kraft lignin to alkyl-phenolics using supported NiMo and CoMo catalysts

The catalytic hydrotreatment of Kraft lignin using sulfided NiMo and CoMo catalysts on different acidic and basic supports (Al2O3, ZSM-5, activated carbon (AC) and MgO-La2O3) was studied in the absence of a solvent. Experiments were carried out in a batch set-up at a reaction temperature of 350 °C, 4 h and 100 bar initial H2 pressure. The catalysts before and after reaction were characterized by X-ray diffraction, temperature programmed desorption of ammonia/CO2, BET surface area and scanning electron microscopy. The liquid products were fractionated and analyzed extensively by different techniques such as GPC, GC-MS-FID, GC-TCD, FT-IR, 13C-NMR and elemental analyses. Two dimensional gas chromatography (GC × GC-FID) was applied to identify distinct groups of compounds (aromatics, alkylphenolics, alkanes) after reaction, and product quantification was performed based on this method. Catalyst activity is a function of the support and increased in the order Al2O3 < ZSM-5 < AC = MgO-La2O3. In addition, the support also largely influenced the extent of depolymerization and monomer yield. The highest lignin oil yields were obtained using the sulfided NiMo supported on activated carbon and MgO-La2O3. The highest total monomer yield 26.4 wt% on lignin intake, which included 15.7 wt% alkyl-phenolics was obtained using the sulfided NiMo/MgO-La2O3 catalyst.

Dehydration of Different Ketoses and Aldoses to 5‐Hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) is considered an important building block for future bio-based chemicals. Here, we present an experimental study using different ketoses (fructose, sorbose, tagatose) and aldoses (glucose, mannose, galactose) under aqueous acidic conditions (65 g L(-1) substrate, 100-160 °C, 33-300 mM H2 SO4 ) to gain insights into reaction pathways for hexose dehydration to HMF. Both reaction rates and HMF selectivities were significantly higher for ketoses than for aldoses, which is in line with literature. Screening and kinetic experiments showed that the reactivity of the different ketoses is a function of the hydroxyl group orientation at the C3 and C4 positions. These results, in combination with DFT calculations, point to a dehydration mechanism involving cyclic intermediates. For aldoses, no influence of the hydroxyl group orientation was observed, indicating a different rate-determining step. The combination of the knowledge from the literature and the findings in this work indicates that aldoses require an isomerization to ketose prior to dehydration to obtain high HMF yields.

Efficient catalytic hydrotreatment of Kraft lignin to alkylphenolics using supported NiW and NiMo catalysts in supercritical methanol

Efficient catalytic hydrotreatment of Kraft lignin to yield aromatic monomers was demonstrated in supercritical methanol using a variety of NiW and NiMo catalysts on acidic, basic and neutral supports. It was found that NiW catalysts on neutral or basic supports are highly suitable for depolymerization of Kraft lignin to methanol soluble organics in high yields at 320 °C and 35 bar H2 pressure. An extensive analysis of the product mixtures was carried out using GC-MS-FID, GC × GC-FID, 2D HSQC NMR, GPC and elemental analysis, and several techniques were used for the characterization of the prepared catalysts in order to determine the acidity and basicity of the support and morphological changes after the catalytic reaction. The best results were obtained with sulphided NiW catalysts supported on activated carbon. Efficient depolymerization of Kraft lignin and a total 28 wt% monomer yield was obtained within 8 h and 76% of the products were alkylphenolics and guaiacolics. Over prolonged reaction times, the total monomer yield reached 35 wt%, containing up to 26 wt% alkylphenolics. During catalytic processing, deoxygenation was the most prevalent reaction and, importantly, no competing aromatic ring hydrogenation or undesired repolymerization to insoluble char was observed. The catalytic system described here represents a highly efficient and selective method for the production of alkylphenolics and guaiacolics from Kraft lignin.