Biomass-derived Platform Chemicals Research Articles

Dually functional NiSi intermetallic compounds for the efficient hydrogenation and oxidation of cinnamaldehyde

Intermetallic compounds (IMCs) are promising catalysts for upgrading biomass-derived platform chemicals. Herein, bifunctional NiSi IMCs catalysts were developed for the hydrogenation and oxidation of cinnamaldehyde (CAL). A solvent-free arc-melting method was employed for the synthesis of NiSi IMCs within 5 min. The NiSi IMCs catalysts afforded 99 % conversion of CAL and presented ∼ 71 % yield of 2-phenyl propanol and ∼ 34 % yield of benzaldehyde for the hydrogenation and base-free oxidation of CAL, respectively. Moreover, NiSi IMCs could be used for five runs without deactivation. Characterizations and theoretical calculation results indicated the formation of intermetallic structure and the existence of Si vacancy sites, which could not only facilitate the efficient hydrogenation of CAL but also expose NiOx species as catalytic centers for the oxidation of CAL, leading to the high performance and stability in both hydrogenation and oxidation process.

The influence of catalyst structure on acidic strength of –SO3H groups for alkyl levulinate synthesis from biomass–derived feedstocks using sulfonic acid functionalized flexible MOF catalyst

A Brönsted acidic BUT−8(Cr)–SO3H metal–organic framework was used for the synthesis of ethyl levulinate from two different biomass–derived platform chemicals viz. furfuryl alcohol and levulinic acid. The catalyst was well characterized using various methods such as PXRD, FTIR spectroscopy, acid–base titration, NH3–TPD, TGA–DTA, SEM, TEM as well as the computational density functional theory (DFT) method. The performance of BUT–8(Cr)–SO3H catalysts was found to be superior to other catalysts (HZSM–5, H–Beta, and amberlyst –15) taken in this study. The sulfonic acid moieties bound to the aromatic naphthalene structure of BUT–8(Cr)–SO3H MOF were found to have a much stronger influence on the catalytic performance than the sulfonic acid moieties bound to the styrene framework of amberlyst–15. The key discoveries regarding the Brönsted acidic characteristics were computed via DFT incorporating the hydrogen removal energy, molecular electrostatic potential maps, and stability of the conjugate base of –SO3H moieties. The trend in the DFT–derived values was in the following order: BUT–8(Cr)–SO3H > Linker–naph –SO3H > Amberlyst–15. The results also indicate the influence of Cr metal on MOF structure to increase the acidic strength of the –SO3H group. The reaction optimization using DOE, recyclability, leaching study, and substrate scope study for both pathways using BUT–8(Cr)–SO3H were obtained.

Sono-catalytic syngas production by low-temperature biomass gasification

Syngas holds a crucial role in diverse industrial applications, including chemical synthesis and power generation. It has been traditionally generated through high-temperature processes, such as steam reforming or biomass gasification, demanding temperatures of up to 1200 °C, which results in substantial energy consumption. Consequently, there is a growing interest in exploring alternative, low-temperature biomass gasification processes. This paper introduces an innovative method for syngas production through sono-catalytic biomass conversion at significantly lower temperatures. The approach employs a sonochemical reactor that concentrates acoustic waves to activate inertial cavitation. Furfural, a biomass-derived platform chemical, was chosen as the primary chemical for the study, showcasing the potential of sonochemical syngas production. The reaction converted furfural into various gas products, particularly a mixture of hydrogen and carbon monoxide, with the chemical reaction hypothesized to be triggered by pyrolysis during bubble collapse hot spots. The incorporation of heterogeneous metal foams into the system further enhanced furfural conversion rates. This improvement was attributed to the preferential nucleation of cavitation bubbles on the porous metal foam surface, bringing the hot spots into proximity with furfural molecules. This application of sonochemistry in furfural pyrolysis at low temperatures holds promise for a more economical approach to biomass valorization.

Ecotoxicological assessment of biomass-derived furan platform chemicals using aquatic and terrestrial bioassays.

An environmental toxicological assessment of fourteen furanic compounds serving as valuable building blocks produced from biomass was performed. The molecules selected included well studied compounds serving as control examples to compare the toxicity exerted against a variety of highly novel furans which have been additionally targeted as potential or current alternatives to biofuels, building blocks and polymer monomers. The impact of the furan platform chemicals targeted on widely applied ecotoxicity model organisms was determined employing the marine bioluminescent bacterium Aliivibrio fischeri and the freshwater green microalgae Raphidocelis subcapitata, while their ecotoxicity effects on plants were assessed using dicotyledonous plants Sinapis alba and Lepidium sativum. Regarding the specific endpoints evaluated, the furans tested were slightly toxic or practically nontoxic for A. fischeri following 5 and 15 min of exposure. Moreover, most of the building blocks did not affect the growth of L. sativum and S. alba at 150 mg L-1 for 72 h of exposure. Specifically, 9 and 11 out of the 14 furan platform chemicals tested were non-effective or stimulant for L. sativum and S. alba respectively. Given that furans comprise common inhibitors in biorefinery fermentations, the growth inhibition of the specific building blocks was studied using the industrial workhorse yeast Saccharomyces cerevisiae, demonstrating insignificant inhibition on eukaryotic cell growth following 6, 12 and 16 h of exposure at a concentration of 500 mg L-1. The study provides baseline information to unravel the ecotoxic effects and to confirm the green aspects of a range of versatile biobased platform molecules.

Insight into the enhanced catalytic performance of phosphate-modified ZrO2/SBA-15 for the conversion of biobased 2,5-dimethylfuran and ethylene into p-xylene

Catalytic conversion of biomass-derived platform chemicals into bulk chemicals p-xylene (PX) is appealing yet challenging due to low catalytic efficiency and severe reaction conditions. In this work, we fabricated a series of phosphate-modified ZrO2/SBA-15 (xP-Zr/SBA-15) via adjusting the addition of phosphoric acid, and used them for the catalytic conversion biomass-derived 2,5-dimethylfuran (DMF) and ethylene to PX. Because of the enhanced adsorption capability for the reactant molecules (DMF and ethylene) and the good synergistic effect between Brønsted acid sites (P-OH) and Lewis acid sites (Zr4+), 30P-Zr/SBA-15 revealed an excellent catalytic performance in the selective conversion of DMF into PX. The DMF conversion was 98.5%, PX yield was 92.0% at 250 °C for 12 h, and the corresponding PX productivity was upto 50.5 mmolPX·gcat−1·h−1. The results are far superior to those obtained on most previously reported catalysts in the literature under similar reaction conditions. The kinetic study revealed that 30P-Zr/SBA-15 has a lower apparent activation energy for the tandem reaction including the Diels-Alder reaction (57.0 kJ·mo−1) and dehydration reaction (37.7 kJ·mo−1). Moreover, the 30P-Zr/SBA-15 catalyst exhibited the excellent recyclability and could be recycled at least six times without a significant loss of activity. On the basis of the temperature-programmed surface reaction of DMF and ethylene, a reasonable reaction mechanism was proposed.

Nickel-Tin Nanoalloy Supported ZnO Catalysts from Mixed-Metal Zeolitic Imidazolate Frameworks for Selective Conversion of Glycerol to 1,2-Propanediol.

The successful synthesis of finely tuned Ni1.5 Sn nanoalloy phases containing ZnO catalyst with a small particle size (6.7 nm) from a mixed-metal zeolitic imidazolate framework (MM-ZIF) is investigated. The catalyst was evaluated for the efficient production of 1,2-propanediol (1,2-PDO) from crude glycerol and comprehensively characterized using several analytical techniques. Among the catalysts, 3Ni1Sn/ZnO (Ni/Sn=3/1) showed the best catalytic performance and produced the highest yield (94.2 %) of 1,2-PDO at ~100 % conversion of glycerol; it also showed low apparent activation energy (15.4 kJ/mol) and excellent stability. The results demonstrated that the synergy between Ni-Sn alloy, finely dispersed Ni metallic sites, and the Lewis acidity of SnOx species-loaded ZnO played a pivotal role in the high activity and selectivity of the catalyst. The confirmation of acetol intermediate and theoretical calculations verify the Ni1.5 Sn phases provide the least energetic pathway for the formation of 1,2-PDO selectively. The reusability of solvent for successive ZIF synthesis, along with the excellent recyclability of the ZIF-derived catalyst, enables an overall sustainable process. We believe that the present synthetic protocol that uses MM-ZIF for the conversion of various biomass-derived platform chemicals into valuable products can be applied to various nanoalloy preparations.

Oxygen vacancy-driven strong metal-support interactions on AuPd/TiO2 catalysts for high-efficient air-oxidation of 5-hydroxymethylfurfural

The regulation ofstrong metal-support interactions (SMSI) has emerged as a powerful strategy in boosting catalytic activity and controlling product selectivity. However, directly tuning the metal-supportinteractions in oxide supported metal nanocatalysts remains challenging. Herein, citric acid (CA)‑assisted synthesized TiO2 layer on halloysite nanotubes (HNTs) with varied oxygen vacancies (Ov) concentrations was designed for loading AuPd nanoparticles. SMSI between the AuPd nanoparticles and the TiO2-xCA@HNTs support was successfully induced by adjustable Ov concentrations. The synthesized catalyst was employed for air-oxidation of bio-based 5-hydroxymethylfurfural (HMF) to bioplastic monomer 2,5-furandicarboxylic acid (FDCA) in water. A satisfactory FDCA yield of 98.4 %, accompany with an outstanding FDCA formation rate of 900.9 mmol·g−1·h−1 and an excellent TOF value at 441.2 h−1 was afforded. Based on catalysts characterizations and experimental studies, the catalytic performance was significantly affected by Ov concentrations. The kinetic study showed that the supported gold nanoparticles in alkaline environment had strong aldehyde oxidation activity but weak alcohol oxidation ability. On the contrary, supported palladium nanoparticles were more conducive to alcohol oxidation. This imbalance was overcome by the loading of AuPd nanoparticles, which enhanced the activity for air-oxidation of HMF. Mechanistic studies demonstrated that the stronginteractions between noble metal nanocatalysts and supports were regulated by Ov, which not only increased the adsorption capacity of the substrate and crucial intermediate, but also facilitated the adsorption and activation of molecular oxygen to generate oxygen active species of superoxide radicals. The possible catalytic mechanism for air-oxidation of HMF over Ov-driven SMSI on the obtained catalysts was proposed. This work sheds lights on the design of supported metal catalysts with SMSI for the catalytic upgrading of biomass-derived platform chemicals.

Efficient conversion of furfural to succinic acid using cobalt-porphyrin based catalysts and molecular oxygen

Metallo-porphyrins have a wide range of applications in both industrial and academic research. This study presents newly designed heterogeneous catalysts comprised of cobalt-porphyrin immobilized on amino-functionalized multi-walled carbon nanotubes (CNT-NH2), which have been synthesized and characterized for potential applications. Five different porphyrin structures were utilized, and the catalyst was thoroughly characterized by various spectroscopic techniques, such as XRD, FT-IR, UV–Vis, 1H NMR, MALDI-FT-ICR MS, N2 adsorption, XPS, and SEM-EDS. The study investigated the catalytic activity of cobalt-porphyrin immobilized on CNT-NH2 in the conversion of furfural to succinic acid using molecular oxygen, with excellent selectivity of 89 % and a yield of 60 % after a 20 h reaction at 100 °C, 3.0 MPa oxygen pressure. The catalyst showed exceptional stability upon multiple reuse, indicating negligible activity loss, highlighting its potential for the efficient aerobic oxidation of biomass-derived platform chemicals into valuable end-products, and underscoring the promise of cobalt-porphyrin immobilized on CNT-NH2 as a catalyst.

Minireview on the Mechanism for the Production of 5-hydroxymethylfurfural from Biomass

Abstract: The synthesis of fuels and fine chemicals from lignocellulosic biomass is the most widely envisioned approach toward the implementation of renewable feedstocks. Significant advances have been made in the selective conversion of biomass-derived platform chemicals. This minireview mainly elucidates the mechanism of biomass-derived 5-hydroxymethylfurfural (HMF) synthesis, including the dehydration of carbohydrates via acyclic and cyclic mechanisms as well as the Maillard reactions. It also highlights the fundamental aspects of reaction mechanisms, recent progress, and challenges.

Photocatalytic Transformation of Biomass and Biomass Derived Compounds-Application to Organic Synthesis.

Biomass and biomass-derived compounds have become an important alternative feedstock for chemical industry. They may replace fossil feedstocks such as mineral oil and related platform chemicals. These compounds may also be transformed conveniently into new innovative products for the medicinal or the agrochemical domain. The production of cosmetics or surfactants as well as materials for different applications are examples for other domains where new platform chemicals obtained from biomass can be used. Photochemical and especially photocatalytic reactions have recently been recognized as being important tools of organic chemistry as they make compounds or compound families available that cannot be or are difficultly synthesized with conventional methods of organic synthesis. The present review gives a short overview with selected examples on photocatalytic reactions of biopolymers, carbohydrates, fatty acids and some biomass-derived platform chemicals such as furans or levoglucosenone. In this article, the focus is on application to organic synthesis.

Recent advances in electrocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid: Mechanism, catalyst, coupling system

Abstract Catalytic synthesis of value-added chemicals from sustainable biomass or biomass-derived platform chemicals is an essential strategy for reducing dependency on fossil fuels. As a precursor for the synthesis of important polymers such as polyesters, polyurethanes, and polyamides, FDCA is a monomer with high added value. Meanwhile, due to its widespread use in chemical industry, 2,5-furandicarboxylic acid (FDCA) has gained significant interest in recent years. In this review, we discuss the electrochemical oxidation of 5-hydroxymethylfurfural (HMF) and summarize the most recent advances in electrode materials from the past 5 years, including reaction mechanisms, catalyst structures, and coupling reactions. First, the effect of pH on the electrocatalytic oxidation of furfural is presented, followed by a systematic summary of the reaction mechanism (direct and indirect oxidation). Then, the advantages, disadvantages, and research progress of precious metal, non-precious metal, and non-metallic HMF electrooxidation catalysts are discussed. In addition, a coupled dual system that combines HMF electrooxidation with hydrogen reduction reaction, CO2 reduction, or N2 reduction for more effective energy utilization is discussed. This review can guide the electrochemical oxidation of furfural and the development of advanced electrocatalyst materials for the implementation and production of renewable resources.

Sustainable isosorbide production by a neat one-pot MW-assisted catalytic glucose conversion

In the context of exploitation of new biomass-derived platform chemicals, isosorbide (1,4:3,6-dianhydro-D-sorbitol), obtained by the two-fold dehydration of sorbitol, is gaining increasing interest in several potential industrial applications. Seeking for more sustainable, efficient, and economically competitive green processes, the use of heterogeneous catalysts under microwave (MW) irradiation has been adopted for the development of a neat one-pot process from glucose. MW-assisted catalytic processes have shown the potential to reduce the reaction time and improve the selectivity, due to the interaction of MW with the reaction medium through the production of hot spots on the catalyst surface. Ru/C, Ru/Al2O3 and Ru/TiO2 were tested for glucose hydrogenation to sorbitol, while the dehydration step was favored by the addition of β Zeolites (360:1 SiO2:Al2O3) allowing high isosorbide selectivity (>85 %). An extended structural and morphological characterization before and after the catalytic tests allowed to establish structure-activity relationships. Yields up to 47.1 % have been obtained directly from glucose in 1.5 h, achieving a considerable reduction of reaction time without the use of a solvent. thus paving the way for further investigations on biomass conversion into value-added products.With this aim, direct isosorbide production from milled cellulose was investigated. While the isosorbide yields still need to be improved, the dual role of formic acid both as acid catalyst for cellulose hydrolysis and H-donor for the reduction step was promisingly clarified.

Design and techno–economic analysis of levulinic acid production process from biomass by using co-product formic acid as a catalyst with minimal waste generation

Levulinic acid (LA) is an essential biomass-derived platform chemical that can be converted into value–added chemicals such as polymers, fertilisers, and pharmaceuticals. However, the high energy demand and cost required in the separation process are significant issues in the LA production process. Recently, formic acid (FA), the co–product in biomass–LA reaction, has been focused on as a catalyst for both biomass pretreatment and LA production. This study designed and numerically simulated a novel process for producing LA from wheat straw (feed rate: 100 kg/h) using an FA aqueous catalyst system (60, 70, and 80 wt%). The reaction data were referred to previous kinetics studies in order to evaluate the feasible reaction time from an economic perspective. The minimised waste generation process was designed by recovering the FA catalyst and using solid residues (lignin and humins) as heat sources. Another byproduct, furfural, was utilised as an extractant for purifying the LA and recovering unreacted products. The minimum selling price (MSP) of the LA and furfural was calculated with an internal rate of return of 6.1% for 20 years. The MSPs were calculated to be 9.59–12.8 USD/kg–products, which was higher than the market price and previous studies. However, the net required energy in this process was − 5.37 to − 32.1 MJ/kg–LA, indicating that the combustion of the solid residue can supply all of the energy required for the process. Our novel concept based on the byproduct utilisation for heat source and extractant can be an effective strategy for an implication of the biorefinery process that can circulate energy with minimum waste generation.

Role of reaction adsorption on the production of 5-hydroxymethylfurfural from fructose under microwave hydrothermal process

5-Hydroxymethylfurfural (HMF) has been considered a valuable biomass-derived platform chemical that can be produced by hexose dehydration in the presence of an acid. However, the yield of HMF is always reduced because of side reactions such as rehydration and condensation. In this work, the reactive adsorption process of fructose dehydration to HMF catalyzed by hydrochloric acid under microwave condition was studied. BP2000 has better adsorption capacity than activated carbon (AC) in reactive adsorption, and addition of BP2000 increases the HMF yield. The maximum theoretical yield of HMF was 65 % obtained by adding 39 g L−1 BP2000 and reacting for 4 min at 160 °C under a microwave hydrothermal condition. It was discovered thatmicrowave hydrothermal technology (MHT) could significantly increase efficiency and reduce reaction time. Reactive adsorption could efficiently buffer HMF from side reactions when reaction conditions became severe, thereby increasing the HMF yield. Reactive adsorption provides a more sustainable method for HMF production and separation.

Zr-KIT-6 catalyzed renewable synthesis of N-aryl pyrroles for producing bioactive synthetic compounds

The sustainable synthesis of bioactive compounds using biomass-derived platform chemicals is essential to meet future chemical demand. Herein a mild and eco-friendly route is presented for structurally diverse pyrrole derivatives from biomass-derived furan. The furans react with aryl amines to construct N-aryl pyrroles in high yields over a robust Lewis acid Zr-KIT-6. Among the synthesized catalysts of this study, Zr-KIT-6 (20) exhibited excellent performance. The same protocol provides a broad utility to synthesize diverse functional pyrrole derivatives. Mechanistic study over Lewis acid Zr-KIT-6 and Bronsted acid KIT-6-SO3H catalysts indicate that the Lewis acid Zr-KIT-6 follows the direct nucleophilic substitution pathway and Bronsted acid KIT-6-SO3H follows the traditional Pall-Knorr reaction pathway. In addition, the co-catalyst-free straightforward domino process requires mild reaction conditions. The broad synthetic utility of the presented methodology was successfully applied to synthesizing biologically active and pharmaceutically relevant antitubercular and antibacterial active N-aryl pyrrole derivatives from renewable furans.

Local reactivity descriptors to decipher the electrochemical hydrogenation of unsaturated carboxylic acids

We explain the intricate interplay between electronic properties and reactivity during the electrochemical hydrogenation of biobased unsaturated (di)acids under acidic and neutral conditions.

Unraveling the reaction mechanisms for furfural electroreduction on copper.

Electrochemical routes for the valorization of biomass-derived feedstock molecules offer sustainable pathways to produce chemicals and fuels. However, the underlying reaction mechanisms for their electrochemical conversion remain elusive. In particular, the exact role of proton-electron coupled transfer and electrocatalytic hydrogenation in the reaction mechanisms for biomass electroreduction are disputed. In this work, we study the reaction mechanism underlying the electroreduction of furfural, an important biomass-derived platform chemical, combining grand-canonical (constant-potential) density functional theory-based microkinetic simulations and pH dependent experiments on Cu under acidic conditions. Our simulations indicate the second PCET step in the reaction pathway to be the rate- and selectivity-determining step for the production of the two main products of furfural electroreduction on Cu, i.e., furfuryl alcohol and 2-methyl furan, at moderate overpotentials. We further identify the source of Cu's ability to produce both products with comparable activity in their nearly equal activation energies. Furthermore, our microkinetic simulations suggest that surface hydrogenation steps play a minor role in determining the overall activity of furfural electroreduction compared to PCET steps due to the low steady-state hydrogen coverage predicted under reaction conditions, the high activation barriers for surface hydrogenation and the observed pH dependence of the reaction. As a theoretical guideline, low pH (<1.5) and moderate potential (ca. -0.5 V vs. SHE) conditions are suggested for selective 2-MF production.

Solvent Free Upgrading of 5-Hydroxymethylfurfural (HMF) with Levulinic Acid to HMF Levulinate Using Tin Exchanged Tungstophosphoric Acid Supported on K-10 Catalyst.

The manufacture of high-value products from biomass derived platform chemicals is becoming an integral part of the biorefinery industry. In this study, we demonstrate a green catalytic process using solvent free conditions for the synthesis of hydroxymethylfurfural (HMF) levulinate from HMF and levulinic acid (LA) over tin exchanged tungstophosphoric acid (DTP) supported on K-10 (montmorillonite K-10 clay) as the catalyst. The structural properties of solid acid catalysts were characterized by using XRD, FT-IR, UV-vis, titration, and SEM techniques. Partial exchange of the H+ of DTP with Sn (x = 1) resulted in enhanced acidity of the catalyst and showed an increase in the catalytic activity as compared to the unsubstituted DTP/K-10 as the catalyst. The effects of different reaction parameters were studied and optimized to get high yields of HMF levulinate. The kinetic model was developed by considering the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism, and the activation energy was calculated to be 41.2 kJ mol-1. The prepared catalysts were easily recycled up to four times without any noticeable loss of activity, and hot filtration test indicated the heterogeneous nature of the catalytic activity. The overall process is environmentally benign and suitable for easy scale up.

Micro/mesoporous LTL derived materials for catalytic transfer hydrogenation and acid reactions of bio-based levulinic acid and furanics.

The biomass-derived platform chemicals furfural and 5-(hydroxymethyl)furfural (HMF) may be converted to α-angelica lactone (AnL) and levulinic acid (LA). Presently, LA (synthesized from carbohydrates) has several multinational market players. Attractive biobased oxygenated fuel additives, solvents, etc., may be produced from AnL and LA via acid and reduction chemistry, namely alkyl levulinates and γ-valerolactone (GVL). In this work, hierarchical hafnium-containing multifunctional Linde type L (LTL) related zeotypes were prepared via top-down strategies, for the chemical valorization of LA, AnL and HMF via integrated catalytic transfer hydrogenation (CTH) and acid reactions in alcohol medium. This is the first report of CTH applications (in general) of LTL related materials. The influence of the post-synthesis treatments/conditions (desilication, dealumination, solid-state impregnation of Hf or Zr) on the material properties and catalytic performances was studied. AnL and LA were converted to 2-butyl levulinate (2BL) and GVL in high total yields of up to ca. 100%, at 200°C, and GVL/2BL molar ratios up to 10. HMF conversion gave mainly the furanic ethers 5-(sec-butoxymethyl)furfural and 2,5-bis(sec-butoxymethyl)furan (up to 63% total yield, in 2-butanol at 200°C/24 h). Mechanistic, reaction kinetics and material characterization studies indicated that the catalytic results depend on a complex interplay of different factors (material properties, type of substrate). The recovered-reused solids performed steadily.

Effects of Water Addition to Isopropanol for Hydrogenation of Compounds Derived from 5-Hydroxymethyl Furfural over Pd, Ru, and Cu Catalysts

We have developed lumped reaction schemes to optimize the yields of products from selective hydrogenations of HAH, a biomass-derived platform chemical produced by two-step aldol condensations of 5-hydroxymethyl furfural (H) with acetone (A). Reaction schemes consisting of 7, 9, and 11 steps were examined to describe the rates of formation of the observed products and reaction intermediates for hydrogenation of HAH over Ru and Pd catalysts, and a 3-step scheme was studied over Cu catalysts. Rate constants and activation energies were calculated using these reaction schemes, and we then apply the schemes to explore the effects of water addition on the hydrogenation pathways. The effects of water addition to isopropanol (IPA) solvents on the hydrogenation of HAH were markedly different over Pd, Ru, and Cu catalysts. Over the Pd catalyst, the addition of water to IPA increased hydrogenation rates and promoted the hydrogenation of furan rings. The addition of water to IPA yielded significant carbon losses over the Ru catalyst, and slowed hydrogenation steps over Cu, while significantly inhibiting hydrogenation of the ketone group. This behavior opened routes toward increased production rates of PHAH═O (a partially hydrogenated, P, form of HAH containing a C═O bond), a product in which the diene groups of the furan rings were not hydrogenated. The addition of water also allowed increased feed concentrations of HAH that were previously not possible in pure IPA solvents. The insights presented in this work provide a more mechanistic description of the hydrogenation of HAH, the behavior of specific intermediates, and the reactivity of key functional groups.