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ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:28 pages:9123-9130 status: published

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:11 pages:3766-3776 status: published

ispartof: Acs Sustainable Chemistry & Engineering vol:10 issue:9 pages:3048-3056 status: published

Following the initial cation formation, the synthesis of ionic liquids (ILs) often involves an anion-exchange or metathesis reaction. For hydrophobic ILs, this is generally performed through several cross-current contacts of the IL with a fresh salt solution of the desired anion. However, if a large number of contacts is required to attain an adequate conversion, this procedure is not economical because of the large excess of the reagent that is consumed. In this study, the metathesis of an IL, Aliquat 336 or [A336][Cl], to ILs with other anions ([A336][X] with X = HSO4–, Br–, NO3–, I–, and SCN–) was studied in a continuous counter-current mixer-settler setup. McCabe–Thiele diagrams were constructed to estimate the required number of stages for quantitative conversion. Significantly higher IL conversions were achieved, combined with reduced reagent consumption and waste production. This improvement in efficiency was most pronounced for anions placed low in the Hofmeister series, for example, HSO4–, Br–, and NO3–, which are difficult to exchange. The performance of the counter-current experiments was compared with the conventional multistep cross-current batch process by calculating the reaction mass efficiency (RME) and the environmental factor (E-factor). The RMEs of the cross-current experiments were notably smaller, that is, 38–78% of the values observed for the counter-current experiments. The E-factors of the counter-current experiments were a factor of 2.0–6.8 smaller than those of the cross-current experiments. These sustainability metrics indicate a highly efficient reagent use and a considerable, simultaneous decrease in waste production for the counter-current IL metathesis reactions., A counter-current flow diagram facilitates the efficient metathesis of ionic liquids and allows for a high conversion with minimal reagent consumption.

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:1 pages:16-22 status: published

Advantages of ionic liquids (ILs) over volatile organic solvents in chemical processes include no or negligible evaporative losses and high tunability. However, the conventional production of aprotic ILs via metathesis can be unattractive (both economically and environmentally) because of its high complexity, while the performance of other synthesis routes remains unclear. Existing life-cycle assessments furthermore fail to combine the production and use phases of these solvents, leading to erroneous conclusion about their sustainability credentials. This paper compares a one-pot, halide-free production route to 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] against metathesis and two conventional fuel desulfurization solvents, namely, acetonitrile and dimethylformamide (DMF). Halide-free synthesis is predicted to reduce the cost and environmental impacts associated with the production of [BMIM][BF4] by 2–5-fold compared to metathesis. Upon including the use phase of the solvents in fuel desulfurization and accounting for the uncertainty in background data, halide-free [BMIM][BF4] consistently presents the lowest cost and environmental impacts, while DMF is the worst in class. As well as exemplifying the importance of synthesis routes of ILs on their sustainability, these results highlight the need to include the use phase of solvents for more comprehensive life-cycle assessments.

There is an environmental concern regarding the use of petroleum-based lubricants, which are generally toxic and nonbiodegradable. Biobased lubricants, such as vegetable oils, are the alternative: they show excellent lubricity, are readily biodegradable and nontoxic. However, a major disadvantage of using vegetable oils in lubricant applications is their lack of thermo-oxidative stability, which can be improved by antioxidant additives. Here, we propose the use of lignin-based additives in biolubricant formulations to improve this feature, based on lignin’s known antioxidant properties. To ensure a stable dispersion in vegetable oil, lignin was partially esterified. Antioxidant properties of lignin before and after palmitoylation were demonstrated in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Four different lignin-based fractions, commercial Protobind P1000 soda lignin from straw, solvolytically fractionated Protobind P1000 lignin and two lignin fractions from reductively catalyzed fractionation (RCF) of native birch wood, were tested in biolubricant formulations with castor oil as base oil. Those lignin fractions exhibited excellent performance compared to butylated hydroxytoluene (BHT), a commonly used petroleum-based antioxidant. Formulations of modified lignin in castor oil possess improved thermo-oxidative stability, as illustrated by their increased oxidation induction time. Additionally, rheological and tribological tests demonstrate similar, or in some cases improved, lubricating properties compared to castor oil. This study showcases the successful incorporation of lignin-based antioxidants in biolubricant formulations, tackling the major disadvantage of vegetable oils as environment-friendly lubricants.

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:9 issue:34 pages:11596-11603 status: published

Continuous-flow sorbitol dehydration in liquid water was performed on β zeolite (Si/Al molar ratio = 75) with conversion of 94 and 83 mol % isosorbide yield. This efficiency is due to the three-dimension pore architecture, high specific surface area (520 m2 g–1), and Brønsted acid sites of 69 μmol g–1. The pore size of β zeolite (6.6 × 6.7 Å2) is slightly larger than the cross section of sorbitol and isosorbide and enables an efficient diffusion of the reactant and product to/from the pores. Operation in continuous flow allows rapid dehydration of sorbitol to 1,4-sorbitan, after which the latter got converted to isosorbide. The high yield of isosorbide is attributed to the continuous removal of the formed products from the catalyst surface. Finally, direct isosorbide production from aqueous glucose solution via hydrogenation on Ni catalyst supported on nitrogen-doped carbon, followed by dehydration of the formed sorbitol to isosorbide, was pioneered.

The selective conversion of lignin or lignin-derived products into bulk chemicals is the foremost challenge for near-future lignocellulosic biorefineries. This study investigates the production of ...

Within the framework of metal separations and solvent extraction, chloride media are among the most studied systems. Bromide and iodide media have received much less attention, but can allow a diff...

Made available in DSpace on 2020-12-12T01:25:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 The use of protic ammonium ionic liquids (PILs) in the pretreatment of lignocellulosic biomass is a promising alternative to using expensive aprotic ionic liquids such as 1-ethyl-3-methylimidazolium acetate, [Emim][OAc]. In this work, the PIL monoethanolammonium acetate, [MEA][OAc], was used for the pretreatment of sugar cane bagasse. The study investigated changing the acid base ratio (ABR) from 0.1 to 10 and recycling of the solvent. We determined the lignin extraction, lignin recovery, solvent recovery, and enzymatic saccharification yield and compared the performance to that of the pure amine base, monoethanolamine. We found that lignin extraction and glucose release during enzymatic saccharification increased with base (amine) content, reaching up to 84% and 96%, respectively, after 72 h of saccharification for the 0.1 ABR. Up to 97% of the solvent was recovered for the 1.0 ABR. A higher acid content led to increased hemicellulose extraction into the liquid phase and reduced ionic liquid recovery. A partial conversion of the PIL into N-(hydroxyethyl) acetamide was observed after pretreatment, with up to 86% of conversion after the sixth use for the 1.0 ABR. A negative correlation (R2 = 0.96) was found between the acetamide content in the solvent and the saccharification yield. The drop in pretreatment performance was also correlated with a decrease in accumulated lignin recovery and the molecular weight of the isolated lignins. Acetamide formation was reduced when excess base was present. Recycling of the mixture with 0.5 ABR showed that the performance was unchanged (97% saccharification yield) after three uses, although 28% of the mixture was converted into the acetamide. The study shows that protic acetate ILs made from primary amines form an equilibrium with their amide and a low ABR is required in order to maintain high pretreatment efficiency when the PIL is reused. Process and Products Development Department Faculty of Chemical Engineering State University of Campinas (UNICAMP), Av. Albert Einstein, 500 Department of Chemical Engineering Imperial College London Department of Bioprocess and Biotechnology College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780 Department of Bioprocess and Biotechnology College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780

Nonaqueous redox flow batteries (RFBs) based on redox-active organic molecules are regarded as a promising technology for large-scale grid energy storage. 1,4-Diaminoanthraquinones (DAAQs) are particularly interesting as active species because they can have up to five different electrochemically accessible oxidation states, but their practical usability is limited because of their low solubility in commonly used polar organic solvents. We present a DAAQ derivative, 1,4-bis((2-(2-(2-methoxyethoxy)ethoxy)ethyl)amino)anthracene-9,10-dione (Me-TEG-DAAQ), which can be synthesized from inexpensive precursors and overcomes this disadvantage of low solubility. This derivative has a low melting point (25 °C), a concentration exceeding 2.2 mol L–1 in the pure state, and is miscible in any ratio with polar organic solvents such as acetonitrile (MeCN) and 1,2-dimethoxyethane. Cyclic voltammetry experiments show that two anodic and two cathodic one-electron redox transitions are electrochemically accessible and highly reversible, with an interval of 1.8 V between the two inner redox couples and 2.7 V between the two outer redox couples. Proof-of-concept galvanostatic cycling experiments were conducted on dilute solutions of Me-TEG-DAAQ in a simple symmetric electrochemical cell. When only the two inner redox couples are considered, the electrochemical cell can achieve specific capacities close to the theoretical value (2.68 A h L–1), with only limited capacity fading (i.e., 49 W h L–1), and limited capacity fading in an electrochemical cell based on one single active species is unprecedented in the RFB literature. ispartof: ACS Sustainable Chemistry & Engineering vol:8 issue:9 pages:3832-3843 status: published

The oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using oxygen (1 atm) with a TEMPO and CuCl catalyst system is investigated using a range of imidazolium-based ionic liquids (ILs) and various bases at different HMF substrate loadings (10-50%). This represents the first example of HMF to DFF conversion in ionic liquid media under homogeneous catalysis conditions, revealing dramatic differences in performance between the ILs. In the non-coordinating, hydrophobic ionic liquid, [bmim][NTf2], 90% DFF yield is obtained at 5 mol% catalyst loading after 6 hours at 80 °C at a very high 40% HMF loading. Increasing the temperature to 100 °C leads to a lower yield, attributed to loss of volatile TEMPO from the reaction medium. A system using TEMPO and pyridine immobilized within the ionic liquid [bmim][NTf2] results in selective conversion of HMF to high purity DFF. It also allows the DFF formed to be isolated by sublimation in 81% yield before a further cycle is performed. Subsequent catalyst deactivation is probed by X-ray photoelectron spectroscopy (XPS). Synthesis from fructose in a two-step process achieves a 55% isolated DFF yield. This approach overcomes significant drawbacks previously reported for this transformation, such as solvent toxicity, separation and purification problems as well as the need for high oxygen pressures. Further oxidation of HMF with this system leads to a 62% yield of 5-formyl-2-furancarboxylic acid (FFCA). The separation of this compound can be achieved by sublimation of DFF followed by solvent extraction.

Lithium is becoming increasingly important due to its essential role in lithium-ion batteries. Over 70% of the global lithium resources are found in salt lake brines, where lithium is always accomp...

Candida rugosa lipase (CRL) is a very versatile and widely used lipase in the aroma and flavor industry, the fat and oil industry, the pharmaceutical industry and is also applicable as a biosensor....

ispartof: Acs Sustainable Chemistry & Engineering vol:10 issue:1 pages:1-2 status: published

Peracetic acid can be used universally as a source of acetate and an oxidant for the selective acetoxylation of C–H bonds in compounds containing ortho-directing groups, catalyzed by Pd(OAc)2. Compared to previous procedures, where persulfates and PhI(OAc)2 were used, the new protocol provides significant improvements in atom efficiency, product yield, substrate scope, cost, scalability, and environmental impact.

© 2018 American Chemical Society. A novel strategy to biobased chemicals with a branched carbon skeleton is introduced. Hereto, small sugars, such as 1,3-dihydroxyacetone, are coupled catalytically to obtain branched C6 sugars, such as dendroketose, in high yield at mild conditions. By bringing this branching step up front, at the level of the sugar feedstock (branching-first), new opportunities for the synthesis of useful chemicals arise. Here, we show that the branched sugar can be efficiently valorized into (i) new branched polyols and (ii) short branched alkanes. The first route preserves most of the original sugar functionality by hydrogenation with Ru/C and renders access to branched polyols with three primary alcohol groups. These molecules are potentially interesting as plasticizers, cross-linkers, or detergent precursors. The second valorization route demonstrates a facile hydrodeoxygenation of the branched sugars toward their corresponding branched alkanes (e.g., 2-methylpentane). The highest alkanes yields (>65 mol % C) are obtained with a Rh/C redox metal catalyst in a biphasic catalytic system, following a HDO mechanism. In the short term, commercial integration of these monobranched alkanes, in contrast to branched polyols, is expected to be straightforward because of their drop-in character and well-known valuable octane booster role when present in gasoline. Accordingly, the branching-first concept is also demonstrated with other small sugars (e.g., tetroses) enabling the production of branched C6-C8 sugars and thus also branched C5-C8 alkanes after HDO. ispartof: ACS Sustainable Chemistry & Engineering vol:6 issue:6 pages:7940-7950 status: published

© 2018 American Chemical Society. Mesostructured silica-carbon nanocomposites with large mesopore interconnectivity are created from sucrose as sustainable carbon source using a mild vapor-phase assisted hydrothermal treatment procedure. The resultant mesostructured silica-carbon nanocomposite can be readily sulfonated to provide a strong acid catalyst with high sulfonic acid density, or the carbon phases of the nanocomposite can be removed by calcination to produce a silica material with ultrahigh porosity (Vpore = 1.25 to 1.34 cm3 g-1). A superior catalytic activity is demonstrated for the solvent-less condensation of 2-methylfuran with furfural; both product yield and conversion rate surpass that of reference catalysts such as their counterparts from dry pyrolysis and the commercial strong acid resins. The enhanced catalytic activity is attributed to the higher SO3H acid density (0.64 to 1.08 mmol g-1), the larger and better communicating mesopores (Vmeso = 0.38 to 0.82 cm3 g-1) and the abundant presence of surface oxygen-containing functional groups on the vapor-phase assisted hydrothermally treated samples. The origin of the well-developed large interconnecting mesopores is investigated and discussed. The mild hydrothermal treatment causes local etching of the original mesopores in the precursor material, creating unexpected interconnectivity between the pores, while the original micropores are basically eliminated during the treatment. Therefore, the here specified hydrothermal treatment provides a promising method to conventional pyrolysis for the efficient and eco-friendly synthesis of highly mesoporous silica-carbon nanocomposites and modification of their physicochemical properties. ispartof: ACS Sustainable Chemistry & Engineering vol:6 issue:6 pages:7859-7870 status: published

This paper studies the economic feasibility of installing hydrogen networks for decarbonising heat in urban areas. The study uses the Heat Infrastructure and Technology (HIT) spatially-resolved optimisation model to trade-off energy supply, infrastructure and end-use technology costs for the most important heat-related energy vectors; gas, heat, electricity, and hydrogen. Two model formulations are applied to UK urban area: one with an independent hydrogen network, and one that allows for retrofitting the gas network into hydrogen. Results show that for average hydrogen price projections, cost-effective pathways for heat decarbonisation towards 2050 comprise including heat networks supplied by a combination of district level heat pumps and gas boilers in the domestic and commercial sectors, and hydrogen boilers in the domestic sector. For a low hydrogen price scenario, when retrofitting the gas network into hydrogen, a cost-effective pathway is replacing gas by hydrogen boilers in the commercial sector, and a mixture of hydrogen boilers and heat networks supplied by district level heat pumps, gas, and hydrogen boilers for the domestic sector. Compared to the first modelled year, CO2 emissions reductions of 88% are achieved by 2050. These results build on previous research on the role of hydrogen in cost-effective heat decarbonisation pathways.

We report on the extraction of lignin from willow and its use to manufacture cellulose-lignin fibers as potential precursors for the manufacture of carbon fibers. The lignin from willow was extracted using triethylammonium hydrogen sulfate [Et3NH][HSO4]. The lignin extracted by this process was characterized by ATR-IR and elemental analysis, which indicated a high carbon yield. 1-Ethyl-3-methylimidazolium acetate [C2C1im][OAc] was then used as a common solvent to dissolve cellulose and lignin to manufacture lignin-cellulose fiber blends. The Young's modulus of a 75:25 lignin/cellulose fiber was found to be 3.0 ± 0.5 GPa, which increased to 5.9 ± 0.6 GPa for a 25:75 lignin/cellulose blend. From a characterization of the surface morphology, using scanning electron microscopy (SEM) and atomic force microscopy (AFM), it was observed that higher lignin content in the fiber blend increased the surface roughness. FT-IR analysis confirmed the presence of aromatic groups related to lignin in the obtained fibers from the presence of peaks located at ∼1505 cm-1 and ∼1607 cm-1. The presence of lignin improves the thermal stability of the fiber blends by allowing them to degrade over a wider temperature range. The presence of lignin also improved the carbon yield during carbonization. Therefore, the lignin-cellulose fibers developed in this work can offer an excellent alternative to pure cellulose or lignin filaments.

A highly selective synthesis of primary amines from alcohols and NH3 was achieved on using a commercially available Ni catalyst, without adding H2. Using a continuous flow reaction platform, the amination of aliphatic alcohols can be achieved in good yields and selectivities, as the accumulation of water byproduct can be removed. Competitive formation of the nitrile side-product was suppressed when the catalyst was prereduced. Modes of catalyst deactivation were also briefly examined.

We report herein a new methodology for the rapid and selective reduction of carbonyls in the solid phase. By exploiting mechanical energy and using a cheap and air-stable silane, polymethylhydrosiloxane (PMHS), we can reduce a variety of carbonyl compounds, with catalytic amounts of fluorides. A scope of 19 substrates was explored to probe the generality of the method. In addition, an important biomass-based platform chemical, 5-hydroxymethylfurfural (5-HMF), and an insoluble polymer, polyketone, could be reduced with this methodology. A mechanistic study is also presented, suggesting the active role of volatile silane species. This method is particularly appealing to overcome substrate solubility issues and reduce solvent reliance in organic synthesis.

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:8 issue:23 pages:8469-8470 status: published

Neodymium and dysprosium can be efficiently separated by solvent extraction, using the neutral extractant Cyanex 923, if the conventional aqueous feed phase is largely replaced by the green polar organic solvent polyethylene glycol 200 (PEG 200). While pure aqueous and pure PEG 200 solutions in the presence of LiCl or HCl were not able to separate the two rare earth elements, high separation factors were observed when extraction was performed from PEG 200 chloride solutions with addition of small amounts of water. This addition of water bridges the gap between traditional hydrometallurgy and novel solvometallurgy and overcomes the challenges faced in both methods. The effect of different variables was investigated: water content, chloride concentration, type of chloride salt, Cyanex 923 concentration, scrubbing agent. A Job plot revealed the extraction stoichiometry is DyCl3·4L, where L is Cyanex 923. The McCabe-Thiele diagram for dysprosium extraction showed that complete extraction of this metal can be achieved by a 3-stage counter-current solvent extraction process, leaving neodymium behind in the raffinate. Finally, a conceptual flow sheet for the separation of neodymium and dysprosium including extraction, scrubbing, stripping, and regeneration steps was presented. The nonaqueous solvent extraction process presented in this paper can contribute to efficient recycling of rare earths from end-of-life neodymium-iron-boron (NdFeB) magnets., Nonaqueous solvent extraction can be integrated in conventional hydrometallurgical flow sheets to provide a sustainable process for the separation of Nd and Dy.

[PdI2(Me2dazdt)] is obtained from palladium powder via a 100% atom economical Pd(0) leaching reaction using Me2dazdt (N,N’-dimethyl-perhydrodiazepine-2,3-dithione) and iodine. This complex is a versatile starting point for ligand exchange reactions with (di)phosphines, yielding trans-[PdI2(PPh3)2] and [PdI2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane). Further reaction with dithiocarbamates provides compounds of the form [Pd(DTC)(L)n]+ (DTC = dithiocarbamate; L = PPh3, n = 2; L = dppe, n = 1), which are highly active catalysts for regio- and chemo-selective C-H bond activation reactions. Using DTC ligands with trimethoxysily-terminated tethers, the palladium(II) units can be attached to the surface of core-shell, silica-coated Fe3O4 nanoparticles. Once tethered, these units formed the catalytically-active component of a recyclable, quasi-heterogeneous, Pd(II)-based catalytic system based on recovered palladium, illustrating the proposed circular model strategy. These investigations contribute to key steps in this process, such as efficient, atom-economical recovery, chemoselectivity of ligand substitution reactions, demonstration of catalytic activity and the potential for immobilization of catalytic surface units derived from recovered metal.

Natural gas is typically considered to be the cleaner-burning fossil fuel that could play an important role within a restricted carbon budget. While natural gas emits less CO2 when burned than other fossil fuels, its main constituent is methane, which has a much stronger climate forcing impact than CO2 in the short term. Estimates of methane emissions in the natural gas supply chain have been the subject of much controversy, due to uncertainties associated with estimation methods, data quality, and assumptions used. This Perspective presents a comprehensive compilation of estimated CO2 and methane emissions across the global natural gas supply chain, with the aim of providing a balanced insight for academia, industry, and policy makers by summarizing the reported data, locating the areas of major uncertainty, and identifying where further work is needed to reduce or remove this uncertainty. Overall, the range of documented estimates of methane emissions across the supply chain is vast among an aggregation of different geological formations, technologies, plant age, gas composition, and regional regulation, not to mention differences in estimation methods. Estimates of combined methane and CO2 emissions ranged from 2 to 42 g CO2 eq/MJ HHV, while methane-only emissions ranged from 0.2% to 10% of produced methane. The methane emissions at the extraction stage are the most contentious issue, with limited data available but potentially large impacts associated with well completions for unconventional gas, liquids unloading, and also the transmission stage. From the range of literature estimates, a constrained range of emissions was estimated that reflects the most recent and reliable estimates: total supply chain GHG emissions were estimated to be between 3.6 and 42.4 g CO2 eq/MJ HHV, with a central estimate of 10.5. The presence of “super emitters”, a small number of facilities or equipment that cause extremely high emissions, is found across all supply chain stages creating a highly skewed emissions distribution. However, various new technologies, mitigation and maintenance approaches, and legislation are driving significant reductions in methane leakage across the natural gas supply chain.

Oxidative depolymerization of lignin obtained from pine and willow can be achieved in a novel system encompassing the ionic liquid (IL) 1-butylimidazolium hydrogensulfate coupled with a vanadium based polyoxometalate (POM) under oxygen rich conditions. Along with an array of phenols and functionalized aromatics, vanillin and syringaldehyde were the main products extracted from the IL. The overall yield of aldehyde products were shown to be higher on lignin samples obtained with shorter pretreatment times, with vanillin being the exclusive aldehyde product obtained from pine. In the presence of molecular oxygen, the highest yield of aldehyde products was obtained when 5 wt % of the POM relative to the IL was employed and constituted the major product in the extracted oils. This system succeeds in exploiting the ability of ILs to depolymerize lignin and the remarkable properties of the POM to oxidize the lignin fragments into useful platform chemicals.

Lignin-first biorefining constitutes a new research field in which the overarching objective is the prevention of lignin recalcitrance while providing high-quality pulps. For this purpose, the solvent extraction of lignin is performed in the presence of a hydrogenation catalyst, employing H2 pressure or an H-donor solvent (e.g., 2-propanol), and thus leading to passivation of reactive lignin fragments via reductive processes. As a result, lignin-first biorefining methods generate high-quality pulps in addition to low-molecular-weight lignin streams with high molecular uniformity. Nonetheless, upon cooking lignocellulose in solvent mixtures containing water, other processes on the lignocellulosic matrix take place, releasing soluble intermediates. In fact, hemicellulose undergoes deacetylation, to a variable extent, releasing acetic acid into the liquor. Moreover, formic acid can also be formed as a degradation product of hemicellulose C6-sugars also released into the liquor. However, despite this general notion, the formation and fate of these carboxylic acids during the cooking of lignocellulosic substrates, and the effects these acids may have on hydrogenation catalyst performance remain poorly understood. In this report, we examine both the formation and subsequent fate of formic acid and acetic acid during lignocellulose deconstruction for both a lignin-first biorefining method (via H-transfer reactions in the presence of Raney Ni catalyst) and its equivalent Organosolv process with no added acid or hydrogenation catalyst. A mechanism for the mitigation of formic acid formation in the presence of Raney Ni catalyst is outlined via the hydrogenation of sugars to sugar alcohols. Furthermore, the effects of the carboxylic acids on Raney Ni performance are assessed, using the transfer-hydrogenation of phenol to cyclohexanol/cyclohexanone as a model reaction, elucidating inhibition rates of the acids. Finally, we conclude with the implications of these results for the design of lignin-first biorefining processes. In a broader context, understanding of the formation and fate of carboxylic acids during CUB is crucial to producing high-quality pulps with high degrees of polymerization and high xylan contents.

ispartof: Acs Sustainable Chemistry & Engineering vol:8 issue:1 pages:1-1 status: published