Upgrading Of Ethanol Research Articles

Upgrading of Ethanol to n-Butanol via a Ruthenium Catalyst in Aqueous Solution

The upgrading of ethanol to n-butanol via the Guerbet reaction in aqueous media has been developed. This system allows for the upgrading of ethanol to n-butanol in up to a 28% yield and 57% selectivity, at only 80 °C. This system is also able to tolerate the same feedstock ratio found in fermentation broth (water to ethanol ratio of 90:10), albeit a decrease in yield and selectivity (20% yield of n-butanol, 48% selectivity). Smaller amounts of longer-chain alcohols are also formed.

Simultaneously boosting hydrogen production and ethanol upgrading using a highly-efficient hollow needle-like copper cobalt sulfide as a bifunctional electrocatalyst

Electrocatalytic water splitting used for generating clean and sustainable hydrogen (H2) can be very promising to address current energy shortage and associated environmental issues. However, this methodology is severely impeded by the tardy oxygen evolution reaction (OER). Hence, designing a preferable kinetics and thermodynamics oxidation reaction that supersede OER is very significant for the energy-saving production of H2. Herein, hollow needle-like copper cobalt sulfide was constructed on carbon cloth (CuCo2S4/CC) as a bifunctional electrocatalyst to accelerate H2 generation and simultaneously convert ethanol into value-added acetic acid. Thanks to the synergistic effect and unique structure of Cu and Co, CuCo2S4/CC displays superior catalytic activity and durability in ethanol oxidation reaction (EOR) with a low potential of 1.38 V vs. RHE (@10 mA cm−2). Meanwhile, it exhibits excellent hydrogen evolution reaction (HER) performance. The homemade CuCo2S4/CC//CuCo2S4/CC ethanol–water electrolyser only demands a voltage of 1.59 V to deliver 10 mA cm−2, 150 mV less than that used for ordinary water splitting. This shows that the ethanol–water electrolyser elaborated here holds encouraging potential in the energy-saving production of H2 and oxidation of ethanol into value-added acetic acid. This present work may open the way for the rational design of other electrocatalysts for efficient biomass oxidation reaction and relevant H2 production applications.

Comparison of acetone–butanol–ethanol fermentation and ethanol catalytic upgrading as pathways for butanol production: A techno-economic and environmental assessment

Butanol is an important compound used as a building block for producing value-added products and an energy carrier. The main butanol production pathways are conventional acetone–butanol–ethanol (ABE) fermentation and catalytic upgrading of ethanol. On the other hand, the application of biomass as a promising substrate for biofuel production has been widely considered recently. However, few studies have compared different butanol production pathways using biomass as raw material. In light of that, the present work aims (i) to provide a short review of the catalytic ethanol upgrading and (ii) to compare conventional ABE fermentation and catalytic ethanol upgrading processes from the economic and environmental perspectives. Aspen Plus v9.0 was used to simulate both processes. The economic and environmental assessments were carried out considering the Colombian economic context, a gate-to-gate approach, and single impact categories. Considering a processing scale of 1000 ton/d, the conventional ABE fermentation process presented a more favorable technical, economic, and environmental performance for butanol production from biomass. It also offered lower net energy consumption (i.e., 57.9 GJ/ton of butanol) and higher butanol production (i.e., 2.59 ton/h). Nevertheless, the proposed processing scale was insufficient to reach economic feasibility for both processes. To overcome this challenge, the minimum processing scale had to be higher than 1584 ton/d and 1920 ton/d for conventional ABE fermentation and catalytic ethanol upgrading, respectively. Another critical factor in enhancing the economic feasibility of both butanol production pathways was the minimum selling price of butanol. More specifically, prices higher than 1.56 USD/kg and 1.80 USD/kg would be required for conventional ABE fermentation and catalytic ethanol upgrading, respectively. From the environmental impact point of view, the conventional ABE fermentation process led to a lower potential environmental impact than catalytic ethanol upgrading (0.12 PEI/kg vs. 0.18 PEI/kg, respectively).

Biocrude Upgrading in Different Solvents after Microalgae Hydrothermal Liquefaction

Hydrothermal liquefaction of the third-generation biomass represented by microalgae can produce biocrude. However, the directly obtained biocrude has a high heteroatom content and a low higher heating value (HHV), which cannot meet the standards of biofuel. In this work, water-insoluble biocrude which was directly gained from microalgae hydrothermal liquefaction (HTL) was upgraded under four kinds of solvents (i.e., methanol, ethanol, acetone, and H₂O) and one type of catalyst (H₂O + Ru/C) at 240–400 °C for 1 h. The results show that the HHV and C and H contents of upgraded bio-oil increased and the O/C ratio decreased significantly after solvent upgrading. The highest upgraded bio-oil yield appeared in the case of ethanol upgrading and reached the maximum value of 82.8 wt % at 360 °C. The upgraded bio-oil yield of acetone upgrading increased from 45.8 to 68.2 wt % as the temperature increased within 240–400 °C. Also, esterification reactions between alcohol and acid in the supercritical system remarkably reduced the content of carboxyl-containing organic matter.

Cell-free synthetic biochemistry upgrading of ethanol to 1,3 butanediol

It is now possible to efficiently fix flue gas CO/CO2 into ethanol using acetogens, thereby making carbon negative ethanol. While the ethanol could be burned as a fuel, returning the CO2 to the atmosphere, it might also be possible to use the fixed carbon in more diverse chemicals, thereby keeping it fixed. Here we describe a simple synthetic biochemistry approach for converting carbon negative ethanol into the synthetic building block chemical 1,3 butanediol (1,3-BDO). The pathway completely conserves carbon from ethanol and can ultimately be powered electrochemically via formate oxidation. Our proof-of-principle system reached a maximum productivity of 0.16 g/L/h and, with replenishment of feedstock and enzymes, achieved a titer of 7.7 g/L. We identify a number of elements that can be addressed in future work to improve both cell-free and cell-based production of 1,3-BDO.

Biorefinery ethanol upgrading: Opportunities and challenges

The production of drop-in replacements for biofuels is a grand challenge. Lignocellulosic biomass is considered a promising feedstock for producing fuel ethanol because of its great availability. Restrepo-Flórez et al. systematically study the upgrading of ethanol toward advanced fuels with tailored properties and with consideration of process synthesis.

Interfacial Sites in Ag Supported Layered Double Oxide for Dehydrogenation Coupling of Ethanol to n-Butanol.

Upgrading of ethanol to n‐butanol through dehydrogenation coupling has received increasing attention due to the wide application of n‐butanol. But the enhancement of ethanol dehydrogenation and followed coupling to produce high selectivity to n‐butanol is still highly desired. Our previous work has reported an acid‐base‐Ag synergistic catalysis, with Ag particles supported on Mg and Al‐containing layered double oxides (Ag/MgAl‐LDO). Here, Ag‐LDO interfaces have been manipulated for dehydrogenation coupling of ethanol to n‐butanol by tailoring the size of Ag particles and the interactions between Ag and LDO. It has been revealed that increasing the population of surface Ag sites at Ag‐LDO interfaces promotes not only the dehydrogenation of ethanol to acetaldehyde but also the subsequent aldol condensation of generated acetaldehyde. A selectivity of up to 76 % to n‐butanol with an ethanol conversion of 44 % has been achieved on Ag/LDO with abundant interfacial Ag sites, much superior to the state‐of‐the‐art catalysts.

Benefits of active site proximity in Cu@UiO-66 catalysts for efficient upgrading of ethanol to n-butanol

The proximity of Cu metal sites and Lewis acid–oxygen vacancy pairs (Zr3–□) dictates the catalytic performance of the upgrading of ethanol to n-butanol.

Mechanistic Understanding of Catalytic Conversion of Ethanol to 1-Butene over 2D-Pillared MFI Zeolite

Ethanol is an important C2 platform molecule for producing value-added chemicals and distillate hydrocarbon fuels (e.g., jet and diesel). Among these, catalytic upgrading of ethanol to butenes can generate valuable commodity chemicals (e.g., 1-butene) and provide C4 olefin intermediates that can be further upgraded to jet/diesel fuels. Two-dimensional (2D) zeolites offer hierarchical mesoporous structures, leading to improved mass transport and reduced diffusion length, which can help to address the coking challenges faced by ethanol conversion to hydrocarbons over three-dimensional (3D) zeolites. In this study, we investigate the acid-catalyzed conversion of ethanol to 1-butene over the Brønsted acid sites (BAS) in 2D-pillared MFI zeolite (2D-PMFI) using ab initio molecular dynamics (AIMD) simulations, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and calorimetric measurements. A detailed thermodynamic analysis, using quasi-harmonic approximation (QHA), on the Gibbs free-energy pathway of ethanol conversion shows that the consideration of entropy is critical to accurately capture the detailed thermodynamic profiles. Employing the Blue Moon ensemble method, the formation of framework-bound butoxide from ethoxy and ethene is found to be the likely rate-determining step (RDS), proceeding via a stepwise mechanism. The reactivity of 2D-PMFI can be further tuned by manipulating RDS through careful control of the number of BAS and operating temperatures. The calculated vibrational density of states (VDOS) validate the structural models of adsorbed ethanol by comparing with the experimental DRIFTS measurements. Overall, our study provides mechanistic insights into ethanol upgrading over the 2D-PMFI and shows the importance of evaluating entropic effects in such a confined system.

Role of Lewis Acids of MIL-101(Cr) in the Upgrading of Ethanol to n-Butanol

The upgrading of bioethanol to n-butanol has recently been a focus of considerable attention due to the advantages of n-butanol over bioethanol as a sustainable fuel. The efficiency of this reaction is highly dependent on the development of catalysts, where understanding how catalysts perform is essential. However, traditional catalysts are normally composed of several kinds of active sites that work together synergistically in reactions, making it challenging to identify the role that individual active sites play. Herein, we synthesized three chromium-based MOFs ((MIL-101(Cr), where MIL stands for Matériaux Institut Lavoisier) with different Lewis acidities but without any basic sites. The linear relationship between Lewis acidities and their dehydration and condensation abilities suggests that there is a competition between the ethanol dehydration to diethyl ether and acetaldehyde condensation on Lewis acids. Upon the introduction of Pd, the Lewis acidity also dominates the particle size of Pd and then the dehydrogenation and hydrogenating abilities of catalysts.

Conversion of Ethanol to n-Butanol over NiCeO2 Based Catalysts: Effects of Metal Dispersion and NiCe Interactions

Conversion of ethanol to n-butanol is of great significance in ethanol upgrading, and multiple sites of metals and oxides are generally coupled for this cascade reaction. Herein, we dispersed Ni an...

Computational and Experimental Mechanistic Insights into the Ethanol-to-Butanol Upgrading Reaction over MgO

The mechanism of ethanol upgrading to higher products is still under debate, especially regarding intermediate species and hydrogenation and dehydrogenation steps. In this work, we conducted a comb...

Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction.

We report a variety of manganese-based catalysts containing both chelating diphosphine (bis(diphenylphosphino)methane (dppm: 1, 2, and 7) or 1,2-bis(diphenylphosphino)ethane (dppe: 3)), and mixed-donor phosphinoamine (2-(diphenylphosphino)ethylamine (dppea: 4–6)) ligands for the upgrading of ethanol and methanol to the advanced biofuel isobutanol. These catalysts show moderate selectivity up to 74% along with turnover numbers greater than 100 over 90 h, with catalyst 2 supported by dppm demonstrating superior performance. The positive effect of substituting the ligand backbone was also displayed with a catalyst supported by C-phenyl-substituted dppm (8) having markedly improved performance compared to the parent dppm catalysts. Catalysts supported by the phosphinoamine ligand dppea are also active for the upgrading of ethanol to n-butanol. These results show that so-called PNP-pincer ligands are not a prerequisite for the use of manganese catalysts in Guerbet chemistry and that simple chelates can be used effectively.

Structure‐activity Relationship of Cu Species in the Ethanol Upgrading to n‐Butanol

AbstractCu‐based catalysts have been widely used in ethanol upgrading to value‐added chemicals, however the selectivity towards target products is still not satisfactory due to the complexity of reaction network. Herein, we take the ethanol conversion to n‐butanol as an example, and demonstrate that there are relationships of the ethanol conversion, the selectivity of n‐butanol and ethyl acetate, and the rate of n‐butanol formation with the ratios of the surface area of Cu0 and Cu+. Both Cu0 and Cu+ are involved in the formation of ethyl acetate, and the ratio is indicative of the catalytic performance, being the higher the ratio, the higher activity of ethanol conversion to n‐butanol but lower selectivity towards ethyl acetate. This work will help develop more efficient and selective catalysts for ethanol upgrading.

Manganese-Catalyzed Dehydrogenative/Deoxygenative Coupling of Alcohols

Valorization of biomass has become an area of intense focus because of the diminishing reserves of crude oil and the ongoing problem of climate change. The principal strategies for the utilization of biomass as a feedstock are (i) to produce biofuels for the transportation sector and (ii) to produce organic commodity chemicals. In this respect, we have developed a serious of manganese-catalyzed dehydrogenative/deoxygenative coupling reactions of lower alcohols, obtainable from oxygen-rich lignocellulosic biomass, to deliver advanced liquid fuels and valuable chemicals.1 Introduction2 Manganese-Catalyzed Upgrading of Ethanol to Butan-1-ol3 Manganese-Catalyzed Selective Upgrading of Ethanol with Methanol to Isobutanol4 Manganese-Catalyzed Acceptorless Dehydrogenative Coupling of Alcohols with Hydroxides to Give Carboxylates5 Manganese-Catalyzed Dual-Deoxygenative Coupling of Primary Alcohols with 2-Arylethanols6 Conclusion

Catalytic upgrading of ethanol to butanol over a binary catalytic system of FeNiOx and LiOH

Catalytic conversion of ethanol to butanol is vital to bridge the gap between huge amounts of ethanol production, the limited blending ratio of ethanol in gasoline, and the outstanding performance of butanol. In this work, a highly active binary catalytic system of FeNiOx and LiOH was developed for upgrading of ethanol to butanol. After 24 h reaction at 493 K, the selectivity to butanol reached 71% with >90% high carbon alcohols at 28% ethanol conversion, which was comparable to the performance of some noble metal homogeneous catalysts.

Metal-Organic Framework-Derived Guerbet Catalyst Effectively Differentiates between Ethanol and Butanol.

RuNi nanoparticles supported on a metal-organic framework (RuNi@MOF) and formed in situ from a ruthenium complex enclosed inside a nickel-based MOF act as a highly active catalyst for the Guerbet reaction of ethanol to 1-butanol, providing turnover numbers up to 725 000 Ru-1. Negligible activity of the RuNi@MOF ethanol upgrading catalyst system toward chemically similar 1-butanol makes it possible to synthesize the competent Guerbet substrate 1-butanol with >99% selectivity.

Microbial electrochemical stimulation of caproate production from ethanol and carbon dioxide

The production of value added chemicals from CO2 is of critical importance for the practical application of microbial electrosynthesis (MES). Here, a binary electron donor (ED) design (using electrode and ethanol) was introduced to provide an efficient caproate production with the bioconversion of both CO2 and ethanol. A maximum caproate production rate of 2.41 ± 0.69 g L−1 d−1, and a final concentration of 7.66 ± 1.38 g L−1 was achieved. Caproate production selectivity based on the substrate increased to 91.47 ± 0.58% (Binary EDs) from 32.22 ± 32.58% (open circuit Electrode ED). An observed amount of 23.43 ± 0.69% of carbon within the final binary ED products originated from the CO2. This work proves for the first time the potential of caproate production from CO2 utilization and ethanol upgrading using solid electrodes to regulate the chain elongation process.

Recent advances in selective C-C bond coupling for ethanol upgrading over balanced Lewis acid-base catalysts

Ethanol is a considerable platform molecule in biomass conversion, which could be acquired in quantity through acetone-butanol-ethanol (ABE) fermentation. People have been working on the upgrading of ethanol to value added chemicals for decades. In the meantime, 1-butanol and a series of value added products have been selectively generated through C–C bond coupling. In this mini-review, we focus on the recent advances in selective C–C bond formation over balanced Lewis acid-base catalysts such as modified metal oxide, mixed metal oxide, hydroxyapatite and zeolite confined transition metal oxide catalysts. Among them, Pd-MgAlO x and Sr-based hydroxyapatite exhibit >70% 1-butanol selectivity, while Zn x Zr y O z and Ta-SiBEA zeolite achieve >80% of isobutene and butadiene selectivity respectively. The mechanism and reaction pathway of C–C bond formation in each reaction system are described in detail. The correlation between C–C bond coupling and the acidity/basicity of the Lewis acid-base pairs from the surface of the catalysts are also discussed.

Ru Promoted MgO and Al-Modified MgO for Ethanol Upgrading

Mg-containing oxides are widely studied as effective catalysts for ethanol upgrading due to their capacity to promote dehydrogenation and coupling reactions. In such systems, the dehydrogenation of ethanol to acetaldehyde is thought to be the rate-determining step, so that the addition of dehydrogenation promoters onto the oxides could be a good way of optimizing the catalysts. Herein, we propose a systematic screening of different catalysts (MgO, Ru/MgO, MgxAlOy, and Ru/MgxAlOy) in order to understand the roles of Ru and of the oxides in the several parallel reactions that occur in the systems. We investigated the catalysts by spectroscopic, textural and bench-scale techniques to correlate microscopic results with macroscopic findings. The insertion of Al into the MgO framework improved activity and product distribution towards ethene. Ru increased ethanol conversion in the systems, but directed the product distribution towards methane.