Candidate Solvents Research Articles

MeSesamol, a bio-based and versatile polar aprotic solvent for organic synthesis and depolymerization

Applications of polar aprotic solvents are inevitable in the chemical industry, but few nonhazardous alternatives are available. Herein, we propose methyl sesamol (MeSesamol) as a promising new bio-based alternative for polar aprotic solvents and demonstrate its versatile applications. MeSesamol was derived from natural resources using environmentally friendly and facile procedures, such as methylation using dimethyl carbonate. MeSesamol has a distinctive smell and demonstrates excellent properties as a green solvent candidate: high boiling and open-cup flash points, immiscibility with water but miscibility with common organic solvents, high stability and resistance to several acids and bases. MeSesamol was an effective solvent in nine C–C coupling reactions, including the Suzuki and Sonogashira reactions and asymmetric Michael addition. MeSesamol lies close to dichloromethane (DCM) in Hansen space and achieves a similar or higher yield and enantiomeric excess (up to 97% and 99%, respectively) in the asymmetric Michael reactions compared to DCM. MeSesamol proved to be an excellent recyclable solvent in the depolymerizations of bisphenol-A polycarbonate (BPA–PC) and polyethylene terephthalate (PET). MeSesamol was recycled in five reaction cycles with excellent efficiency (92%–100%) and outstanding cumulative monomer yields (92% bisphenol-A from BPA–PC and 92% terephthalic acid from PET). To properly compare the depolymerization reactions, we propose two green metrics, namely, the corrected energy-economy factor (εcorr) and the corrected environmental energy impact (ξcorr).

Multi-Criteria Screening of Organic Ethanolamines for Efficient CO2 Capture Based on Group Contribution Method

Amine solvent has attracted much attention due to its high CO2 capture level and wide application range, but its high energy consumption for recycling restricts its large-scale commercialization. In this work, a multi-objective optimization technology based on the group contribution method was used to select potential amine solvents for CO2 capture. This computer-aided molecular design method considers the thermodynamic and kinetic properties of the candidate solvent and evaluates the influence of relevant parameters on solvent performance. Compared with previous experimental methods used to optimize solvent, this method selects potential solvents from a large number of solvent databases based on group contribution. Firstly, a corresponding classification database was established for various kinds of amine solvents. Then, the traditional experiments were used to verify and screen solvents. At the same time, the method was applied to 31 amine absorbents concerning solubility, molar volume, surface tension, heat capacity, viscosity, pKa, saturated vapor pressure, and so on, and seven solvents were found to have comparable performance to MEA, with higher absorption rates and solubility. This method provides guidance for screening CO2 capture absorbents with economic viability, high efficiency, fast absorption rates, and low regeneration energy consumption.

Computational Assessment of an Amine-Based Solvent Library for High-Salinity Brine Desalination

Human population growth has increased the demand for freshwater. Simultaneously, improvements to high-salinity brine desalination technology are needed to treat wastewater from expanding industrial activities. Temperature-swing solvent extraction (TSSE), initially proposed in the 1960s for low-salinity brine desalination, has recently been found to be effective for processing high-salinity brines. Although there have been several individual investigations performed to test the TSSE performance of various amine-based solvents, the desired molecular properties of the best solvent candidates remain unknown. Using molecular simulation data and an unsupervised learning method, the molecular characteristics of 60 different amine-based solvents are analyzed and grouped into clusters based on their thermodynamic properties, such as density, heat of vaporization, volumetric thermal expansion coefficient, solvent–solvent binding free energy, solvation free energy, and number of hydrogen-bonds. Solvents with features most similar to one of the best current TSSE solvents (diisopropylamine) were analyzed further by simulating brine–water interfacial systems. Among the 59 amine-based solvents compared to diisopropylamine, we find that secondary amines with a six-carbon branched or linear structure display the most promising TSSE performance and should be experimentally investigated in the future.

A New Inert Natural Deep Eutectic Solvent (NADES) as a Reaction Medium for Food-Grade Maillard-Type Model Reactions.

Sustainability, low toxicity, and high solute potential are the fundamental reasons for focusing green chemistry on natural deep eutectic solvents (NADES). The application of NADES ranges from organic chemistry to the agricultural sector and the food industry. In the food industry, the desired food quality can be achieved by the extraction of small molecules, macromolecules, and even heavy metals. The compound yield in Maillard-type model reactions can also be increased using NADES. To extend the so-called "kitchen-type chemistry" field, an inert, food-grade NADES system based on sucrose/D-sorbitol was developed, characterized, and examined for its ability as a reaction medium by evaluating its temperature and pH stability. Reaction boundary conditions were determined at 100 °C for three hours with a pH range of 3.7-9.0. As proof of principle, two Maillard-type model reactions were implemented to generate the taste-modulating compounds N2-(1-carboxyethyl)guanosine 5'-monophosphate) (161.8 µmol/mmol) and N2-(furfuryl thiomethyl)guanosine 5'-monophosphate (95.7 µmol/g). Since the yields of both compounds are higher than their respective taste-modulating thresholds, the newly developed NADES is well-suited for these types of "kitchen-type chemistry" and, therefore, a potential solvent candidate for a wide range of applications in the food industry.

The quest for a better solvent for the direct hydration of cyclohexene: From molecular screening to process design

Cylcohexanol is an essential bulk chemical that can be produced via cyclohexene hydration, a liquid-liquid two-phase reaction that is limited by the low reaction rate and the equilibrium conversion. Adding an appropriate solvent is the most promising method to break through these limitations. However, in previous works the solvent was almost blindly selected without a global consideration. In this work, a rational multiscale method is proposed for the effective selection of an economical and sustainable solvent for the direct hydration of cyclohexene. At the molecular scale, liquid-liquid phase equilibrium was estimated using group contribution methods to rapidly screen the potential solvent candidates from a range of organics, based on the partition coefficient. At the reactor scale, the candidates were experimentally investigated to pick out the solvents that could significantly improve the conversion, without introducing side reactions or deactivating the catalyst. At the process scale, the total annual cost (TAC), CO2 emission, and other metrics were calculated to evaluate the eco-efficiency of all solvents. Using this multi-scale method, acetophenone was selected as an eco-efficient solvent from over 100 organics, resulting in the reduction of TAC by 8 % and CO2 emission by 17 % in the production process. Using acetophenone also led to the increase of cyclohexanol yield from 12.3 % to 27.6 % without the occurrence of side reactions and catalyst deactivation.

From Molecules to Heat‐Integrated Processes: Computer‐Aided Design of Solvents and Processes Using Quantum Chemistry

AbstractSolvents are key to many chemical and energy conversion processes. Solvents should be selected as part of process design, optimizing a process‐level objective to account for the interactions between molecular properties and process performance. In this paper, we integrate the computer‐aided molecular design of solvents with the design of heat‐integrated processes for minimum utility demand. The process flowsheet is represented by thermodynamically accurate shortcut process models, encompassing the most common unit operations: extraction, distillation, absorption, and multiphase reaction. For each candidate solvent, we optimize the process considering heat integration and design solvents based on their process performance. All thermodynamic properties are predicted using quantum chemistry. The method is applied to two case studies: extraction‐distillation and integrated carbon capture and utilization. In both studies, designed solvents improve process performance compared to literature benchmarks, where simpler heuristics lead to suboptimal choices. Thus, the results highlight the importance of integrating molecular and process design to achieve maximum process performance.

COSMO‐CAMPED – Solvent Design for an Extraction Distillation Considering Molecular, Process, Equipment, and Economic Optimization

AbstractFor an extraction process to be economically feasible, selecting a suitable solvent is imperative. This work extends the computer‐aided molecular and process design (CAMPD) framework COSMO‐CAMPD for solvent design in an extraction‐distillation process by replacing a pinch‐based process model with a hybrid, rate‐based extraction‐distillation process model. The resulting CAMPD framework is able to evaluate solvent candidates by investment costs in addition to operating costs in a fully predictive manner. In a case study for purifying acetone, we show that our framework's guided exploration of a vast design space yields solvents with superior performance compared to a benchmark solvent from the literature.

A predictive group-contribution framework for the thermodynamic modelling of CO[formula omitted] absorption in cyclic amines, alkyl polyamines, alkanolamines and phase-change amines: New data and SAFT-[formula omitted] Mie parameters

A significant effort is under way to identify improved solvents for carbon dioxide (CO2) capture by chemisorption. We develop a predictive framework that is applicable to aqueous solvent + CO2 mixtures containing cyclic amines, alkyl polyamines, and alkanolamines. A number of the mixtures studied exhibit liquid–liquid phase separation, a behaviour that has shown promise in reducing the energetic cost of CO2 capture. The proposed framework is based on the SAFT-γ Mie group-contribution (GC) approach, in which chemical reactions are described via physical association models that allow a simpler, implicit, treatment of the chemical speciation characteristic of these mixtures. We use previously optimized group interaction parameters between some amine groups and water (Perdomo et al., 2021), and develop new group interactions for the cNH, cN, NH2, NH, N, cCHNH, and cCHN groups with CO2; a set of second-order group parameters are also developed to account for proximity effects in some alkanolamines. A combination of literature data and new experimental measurements for the absorption of CO2 in aqueous cyclohexylamine systems obtained in our current work, are used to develop and test the proposed models. The SAFT-γ Mie GC approach is used to predict the thermodynamics of selected mixtures, including ternary phase diagrams and mixing properties relevant in the context of CO2 capture. The current work constitutes a substantial extension of the range of aqueous amine-based solvents that can be modelled and thus offers the most comprehensive thermodynamically consistent platform to date to screen novel candidate solvents for CO2 capture.

Improved Electrochemical Performances of Li/CFx-MnO2 Primary Batteries Via the Optimization of Electrolytes

The lithium(Li) primary batteries have been widely used in power sources for military applications. According to the military standards, the design temperatures for the basic climate category including the mid-altitude areas will include the ambient air temperature range of -32oC through +60oC, considering the operational, storage, and transit conditions of materiel systems. Among a variety of Li primary batteries, lithium/thionyl chloride (Li/SOCl2) primary batteries have been commonly utilized in military applications due to their high energy density, high operating voltage, and competitive cost. However, Li/SOCl2 batteries have serious challenges due to initial voltage delay by lithium chloride passivation layer and possible safety issues by a formation of toxic sulfur-dioxide (SO2) gas and solid sulfur during discharge. To overcome the intrinsic disadvantages of Li/SOCl2 batteries, research into lithium/carbon fluoride-manganese dioxide (Li/CFx-MnO2) batteries has been ramped up for military applications due to their high energy density and good rate capability. In this study, we have focused on an optimization of solvents and Li salts to improve the electrochemical performances of Li/CFx-MnO2 batteries in a wide operating temperature ranges. We have investigated candidate solvents for Li/CFx-MnO2 batteries with different compositions of methyl butyrate (MB) and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) as well as conventional solvents including propylene carbonate (PC), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), ethyl acetate (EA), and 1,2-dioxolane (DOL). Moreover, we have investigated the effects of Li salts, lithium perchlorate (LiClO4) and lithium bis(trifluoromethanesulfonyl)imide (LiFSI), on the electrochemical performances in the low and high operating temperatures. Ionic conductivity measurements and differential scanning calorimetry (DSC) analysis were also carried out to investigate the physical properties and stability of electrolyte. This study will provide an opportunity to develop the new electrolyte systems for Li/CFx-MnO2 batteries in a wide operating temperature window.

Biofuel Additives: Thermodynamic Studies of Glycerol Ethers

Glycerol offers vast potential for the design of new “green” solvents and molecular building blocks from naturally derived resources. Etherification of glycerol at one or more of the three alcohols yields large decreases in viscosity and makes the resulting products attractive “green” solvent candidates. Our prior works have demonstrated efficient synthesis of 1,3-diether-2-alcohol, 1,3-diether-2-ketone, and 1,2,3-triether compounds with glycerol skeletons with a variety of functional groups in both symmetric and asymmetric patterns. As the potential applications for these compounds become more widely explored, there is a need to understand their properties so that they may be properly evaluated for use in existing and new process technologies. In this work, the thermodynamic properties of four glycerol ethers with systematically varied functional groups are measured and evaluated. Data reported will not only help supplement the library of glycerol derivative properties, but also provide guidance for the development of novel biofuel additives.

High-throughput computational solvent screening for lignocellulosic biomass processing

Lignocellulose is one of the most promising renewable bioresources for the production of chemicals. For sustainable and competitive biorefineries, effective valorization of all biomass fractions is crucial. However, current efforts in lignocellulose fractionation are limited by the use of either toxic or suboptimal solvents that do not always allow producing clean and homogeneous streams. Here, we present a computational screening approach that covers more than 8000 solvent candidates for the processing of lignocellulosic biomass. The automated screening identified highly effective, non-intuitive solvents based on physico-chemical properties, solubilities of the biomass fractions, and environmental, health and safety properties. Solubility experiments for the lignin and cellulose fraction confirmed the applicability of the proposed framework in biomass processing. In addition to the traditional “lignin-first” approaches, we identified solvents applicable for the complete dissolution of biomass. Furthermore, we elucidated particular structural patterns in solvents featuring high lignin solubility. The most promising solvents attained lignin solubilities of more than 33 wt%.

A Carboxylic Ester-Based Electrolyte with Additive to Improve Performance of Lithium Batteries at Ultra-Low Temperature

Lithium metal batteries (LMBs) are the promising battery system to push energy density to high level at low temperatures. In this work, the linear carboxylic esters methyl propionate (MP)-based electrolyte with 4 wt% fluorinated ethylene carbonate (FEC) is reported. The low melting point and viscosity of MP makes it the candidate solvent for the low temperature field. Assisted with FEC, the optimized electrolyte shows quite high ionic conductivity and better compatibility with separator and lithium metal anode, resulting in stable cycling performance at room temperature. Besides, it keeps liquid state at −70 °C and exhibits lower binding energy with lithium ion, enabling the Li/LiCoO2 batteries to cycle at −40 °C for 60 cycles. Apart from that, this battery can retain 88.6% discharge capacity at −70 °C of that at room temperature, reaching the highest discharge capacity retention at this ultra-low temperature to the best of our knowledge. This work demonstrates a simple but effective way to design the electrolytes with excellent low temperature performance.

Continuous extraction of naphthenic acid from low-grade oil using 1,6-hexanediol in an ammonia solution

The efficient use of low-quality crude oil is one short-term solution to overcoming the imminent energy crisis due to the depletion of fossil resources. Several methods have been developed to upgrade low-quality oil, the most important part of which is the removal of acidic components. High-acid crudes can be converted to lower-acid crudes using various methods based on physical and chemical principles. In this contribution, we suggest an efficient and economical method based on liquid–liquid extraction. The candidate solvent was screened from a thermodynamic analysis in a previous study, and the additives and process conditions were adjusted according to experimental results. As the final solvent choice, 1,6-hexanediol in an aqueous ammonia solution showed the best performance with the minimal amount of solvent (weight fraction of 0.6). Experiments showed that the proposed solvent can be used to treat real crude oil used in the industry. A continuous operation scheme was suggested with solvent regeneration and recycling combined with separation of the acidic residue. The results showed that the proposed extraction process can reduce 85% of the acidic component in high-acid crudes and that repeated use of the solvent is possible.

Modeling of Carbon Dioxide Separation by Aqueous Ammonia Solution in a Hollow‐Fiber Membrane Contactor

AbstractCO2 separation from gaseous mixtures in a hollow‐fiber membrane contactor (HFMC) with conventional solvents has a high energy cost. Aqueous ammonia is an industrial solvent candidate that provides better features. A mass transfer model was developed to investigate the effect of operating parameters on the separation performance of an HFMC using aqueous ammonia for CO2 removal. The governing equations were solved numerically. The influence of the liquid flow rate, liquid concentration, and gas flow rate on CO2 removal was studied at different CO2 inlet concentrations. The liquid flow rate had a slight effect on the CO2 concentration at the shell exit, while the CO2 removal significantly changed with variation of the gas flow rate. Moreover, the proposed model can predict CO2 removal as well as axial and radial CO2 concentration profiles in the HFMC as a function of the main operating parameters.

Free volume theory and extended mixing rule implementation for estimation of liquid viscosity of flue gas desulphurization candidate solvents

The free volume theory model was used to estimate viscosity of eight pure substances and their twenty-three binary mixtures. The selected viscosity data included compounds such as alcohol, ether, lactam, amine and polymer, measured at atmospheric pressure and in the temperature range (288.15–318.15/323.15/333.15) K depending on the used pure chemical. For pure substances free volume theory is a correlative three-parameter model, while for mixtures different approaches were tested regarding the number of parameters in the proposed extended logarithmic mixing rule, and showed that the optimal one in terms of complexity and yet with good results, also has three parameters to be optimized. The usage of the simplified model, without dilute gas term, was justified by the values of absolute average deviations for both pure component and mixtures. The model was also coupled with different equations of state (Peng-Robinson and Soave-Redlich-Kwong) for calculation of needed density data, in cases when experimental density data are missing. For pure chemicals, values of absolute average deviations are up to 2.3% for tested polymers, and below 0.8% for other classes of chemicals. For binary mixtures overall deviations go to 1% for eleven systems without polymer and to 3.8% for twelve systems with polymer as one compound. Comparison with friction theory is slightly in favor of friction theory for pure compounds, but involves higher number of parameters, while for the mixtures free volume theory showed significantly better results with the same number of optimized parameters.

Engineering solid electrolyte interphase for the application of propylene carbonate solvent for graphite anode in low temperate battery

Propylene carbonate (PC) is regarded as a good candidate solvent for low-temperature electrolyte applications due to its low melting point (−49.2 °C). However, the co-intercalation of PC into the graphite anode limits its use in low-temperature electrolytes. Along these lines, in this work, by pre-growing a stable solid electrolyte interphase (SEI) on the graphite anode in 1 M LiPF6 FEC: DMC electrolyte, it was found that the co-intercalation of PC into graphite can be inhibited when the latter was cycled in 1 M LiDFOB EC: PC: DEC electrolyte. As was observed by in-situ Electrochemical atomic force microscopy (EC-AFM) measurements, the SEI film has a double-layer structure. Additionally, no gas generation was detected by differential electrochemical mass spectrometry (DEMS) during the cycling, demonstrating the stability of the SEI layer. The addition of PC improves the low-temperature performance of the battery, which can be charged and discharged at −20 °C, while the discharge capacity can reach about 75% of room temperature’s discharge capacity. Our work provides a new idea for the design of low-temperature PC-based electrolytes for the next-generation battery systems.

Potential solvents and electrolytes for energy storage applications: A Review

Since the industrial sector leans more on fossil fuels to pace up with the required energy needs. To overcome increasing demand for electricity, it is important to store the energy generated from natural resources so that energy can be used as and when required. Energy storage devices are one such means used worldwide for conserving different forms of energies and need of the hour is to discover and explore strong and secure electrical energy storage technologies. In this review an effort is made to do a comparative analysis of various types of materials and solvents used for energy storage applications during last two decades. Attempt has also been made to explore and discover different class of solvents and electrolytes that are environment friendly and have minimal impact on living organisms. As salts and the solvents are significant ingredients in the energy storage devices, so this analysis will also provide a first-hand perspective of many solvent candidates for energy storage applications. From the analysis and detailed review, it has been observed that the solvents exhibiting large electrochemical window, high thermal and chemical stability, low toxicity, and volatility are the important features which makes them important constituent of different energy storage devices like flow batteries, supercapacitors, and rechargeable batteries. Advancement of cutting-edge battery innovation is important in view of various applications like hybrid cars, smartphones, laptops etc.

Machine-learning-guided reaction kinetics prediction towards solvent identification for chemical absorption of carbonyl sulfide

Exploring solvents for chemical absorption of carbonyl sulfide (COS) is largely hindered because of challenging study of reaction kinetics by means of either experimental or computational methods. Machine learning (ML) has been proven to greatly accelerate information identification and function achievement in academic and industrial fields. Herein, we report a machine-learning-guided reaction kinetics prediction for intelligent identification of promising compounds for chemical absorption of COS. The rate-determining step for solvent-involved reaction of COS was firstly recognized and the reaction rate constants of determining step were obtained via quantum chemistry computations in order to establish the initial training dataset. Furthermore, two molecular descriptors, alphaV and betaV, representing the steric hindrance around the amine groups were defined to build the ML algorithm and the SHapley Additive exPlanations (SHAP) approach was used to interpret the model. By introducing four specific descriptors, our ML model exhibits the largely reduced mean absolute error (MAE) of 0.80 for predicting the rate constants (logk) for COS reaction with potential solvents. These reaction rates are primarily determined by the charge distribution and steric hindrance of solvent molecules. Documented data confirm that our ML model involving custom-defined molecular descriptors successfully predict the reaction kinetics. This study enables a general strategy for machine-learning-guided exploration and identification of solvent candidates for compound capture and separation through chemical absorption process.

Effect of solvent on CO2 absorption performance in the microchannel

The absorption performances of CO2 into 2–amino–2–methyl–1–propanol (AMP) solutions mixed with solvents water, ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were investigated and compared in a T–junction microchannel. The absorption rate under different liquid flow rates (10–40 ml·h−1), gas/liquid flow rate ratios (0.5–10) and AMP concentrations (0.2–0.8 mol·L–1) was determined by the online photographic method. The dynamics (bubble and slug lengths, film thickness, recirculation frequency in slug, film–slug exchange and pressure drop) in the slug–flow region were analyzed and discussed. The results show that solvents affect the absorption rate with the order of AMP–water < AMP–EG < AMP–DEG < AMP–TEG, which is opposite to their solubility. The increased pressure drop and shorter bubble surrounded with thicker film are the dominant factors affecting the absorption rate, which increase the concentration driving of CO2 and film–slug mass exchange at the higher solvent viscosity respectively. Under current conditions, water is a good solvent candidate by joint consideration of absorption rate and energy consumption. This study provides guidance for solvent selection and manipulation of CO2 absorption in the microreactor.

Model-Based Simultaneous Solvent Screening and Column Design Based on a Holistic Consideration of Extraction and Solvent Recovery.

A methodology for a model-based simultaneous solvent screening and dimensioning of extraction columns is presented. Therefore, a rate-based extraction model is combined with a distillation model for solvent recovery and product purification to consider the whole extraction process. The optimal operating point and the required column dimensions are determined for each solvent candidate specifically to minimize total costs, which are used as a basis for solvent ranking. The methodology is applied to the extraction of levulinic acid from an aqueous feed with a special focus on the influence of mutual solubility between the solvent candidates and water. It is shown that using mixture properties for both phases in accordance with the mutual solubility significantly impacts the calculation of fluid dynamics, mass transfer, and thereby on the required extraction column height. Furthermore, additional costs due to solvents solubilized in the aqueous raffinate strongly affect the economic evaluation of the solvents.