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Solvents are at the heart of many research and industrial chemical processes and consumer product formulations, yet an overwhelming number are derived from fossils. This is despite societal and legislative push that more products be produced from carbon-neutral resources, so as to reduce our carbon footprint and environmental impact. Biomass is a promising renewable alternative resource for producing bio-solvents, and this review focuses on their extraction and synthesis on a laboratory and large scale. Starch, lignocellulose, plant oils, animal fats and proteins have been combined with creative synthetic pathways, novel technologies and processes to afford known or new bio-derived solvents including acids, alkanes, aromatics, ionic liquids (ILs), furans, esters, ethers, liquid polymers and deep eutectic solvents (DESs)—all with unique physiochemical properties that warrant their use as solvation agents in manufacturing, pharmaceutical, cosmetics, chemicals, energy, food and beverage industries, etc. Selected bio-solvents, conversion technologies and processes operating at commercial and demonstration scale including (1) Solvay’s Augeo™ SL 191 renewable solvent, (2) Circa Group’s Furacell™ technology and process for making levoglucosenone (LGO) to produce dihydrolevoglucosenone (marketed as Cyrene™), (3) Sappi’s Xylex® technology and demonstration scale processes that aim to manufacture precursors for bio-solvents and (4) Anellotech’s Bio-TCat™ technology and process for producing benzene, toluene and xylenes (BTX) are highlighted.
Department of Chemical Sciences, University of Johannesburg, Johannesburg, South Africa
Leah C. Matsinha
Department of Chemical Sciences, University of Johannesburg, Johannesburg, South Africa
Banothile C.E. Makhubela*
Department of Chemical Sciences, University of Johannesburg, Johannesburg, South Africa
*Address all correspondence to: bmakhubela@uj.ac.za
1. Introduction
Air quality deterioration, environmental, health and safety issues have raised serious concerns over continued processing of fossil-based feedstocks in producing chemical products such as fuels and solvents. As such, many efforts are being made to reduce the use of hazardous substances (particularly volatile organic solvents (VOCs)) and to eliminate or minimize waste generation in chemical processes. Switching from the currently widely used fossil-based solvents to greener ones derived from renewable resources constitutes a key strategy to drive sustainability as well as clean and safer chemical procedures in both industry and academia [1, 2].
Solvents are central to many chemical processes as they dissolve reagents and ensure sufficient interactions, at a molecular level, for chemical transformations to take place. For instance, the pharmaceutical industry is heavily reliant on solvents for drug discovery, process development and drug manufacturing processes [3]. They are also used to extract and separate compounds from mixtures or natural products. Solvents are also important for performing compound purifications and form part of many manufacturing protocols as well as consumer products including fragrances, cleaning agents, cosmetics, paints, flavors, adhesives and inks, to name a few [1].
Many organic solvents are volatile, flammable and toxic; therefore, their use poses safety and health risks and impacts negatively on the environment. In order to address these issues, ‘solvent-free’ chemistry has been proposed, to mitigate against solvent exposure risks, and for chemical manipulations and formulations that absolutely require solvents, a system of ranking them by their environmental, safety and health (ESH) attributes has been introduced. This system aims to aid in selecting and using those solvents with minimum ESH risks and good green profiles [4, 5, 6].
Making use of renewable resources in producing solvents is a promising and important strategy to move towards sustainable chemical processing and to replace organic solvents derived from fossil raw materials. To this end, bio-based feedstocks such as carbohydrates, carbohydrate polymers, proteins, alkaloids, plant oils and animal fats have been used to produce bio-based solvents (Figure 1). This often requires prior processing of the raw materials (typical by thermochemical and biochemical conversion methods) to give familiar solvents or to provide completely new and innovative solvent entries [7, 8]. There are some, such as essential oils extracted from citrus peels (which are rich in terpenes), that are used directly.
Figure 1.
The various sustainable solvents derived from biomass.
The main processing methods include biochemical and thermochemical conversion [7]. Using one or a combination of these processing techniques, several classes of bio-based solvents (including alcohols [9, 10, 11], esters [12, 13], ethers [14], alkanes [15], aromatics [16] and neoterics [17, 18]) can be manufactured (Figure 1).
Bio-based ethanol is currently the most produced of all bio-solvents and is produced through biological transformation of sugars. These processes use either edible (sugarcane and corn) or nonedible (cellulose) feedstocks [19]. However, due to concerns over edible feedstock causing the rise of food prices, there has been a move towards optimizing processes that produce cellulosic ethanol [20, 21], and indeed the world’s first cellulosic ethanol commercial-scale production plant was commissioned in 2013 by Beta Renewable. This plant is situated in Milan, Italy, and uses Proesa™ technology for the pretreatment of agricultural waste (such as rice straw, giant cane (Arundo donax) and wheat straw) for production of ethanol at 60,000 tons/year [9].
Ethanol’s most common uses are as a biofuel and solvent in consumer products such as perfumes, food coloring and flavoring, alcoholic drinks and in certain mediation. The latter can be in both synthetic medicines and natural products. For example, highly efficient ethanol-assisted extraction of artemisinin, an active antimalarial drug, from Artemisia annua, has been demonstrated [22].
The presence of the hydroxyl group in ethanol makes it capable of hydrogen bonding, and it is therefore miscible with water and other solvents such as toluene, pentane and acetone.
Large-scale production of methanol is currently achieved using fossil-derived sources, by hydrogenation of carbon monoxide in the presence of a catalyst such as ZnO/Cr2O3 and Cu/ZnO/Al2O3 [23]. It can be obtained in small amounts in fermentation broths and from the gasification of biomass to produce bio-based syngas for subsequent conversion to methanol. The commercial viability of the latter is still under investigation [24].
Due to the structural similarity of methanol to ethanol, the former is often used in place of ethanol in synthetic procedures. However, its toxicity has limited its widespread application as a solvent in consumer products. Still, other useful applications where methanol features not only as a solvent but as a reagent and fuel do exist. For instance, methanol is used in methanol fuel cells and is a key reagent in the manufacture of fatty acid methyl esters (FAMEs) (biodiesel) through transesterification of triglycerides and in dimethyl ether (DME) (diesel substitute) production [24]. It is also used in acid-catalyzed formation of methyl levulinate from bio-derived furfural alcohol (FA) and 2,5-hydroxymethylfurfural (HMF) [25].
Thermochemical synthesis of alcohols such as methanol, ethanol and propanol (1-propanol and 2-propanol) from glycerol raw materials (Figure 2) is also known. This process is often promoted by a catalyst through a hydrogenolysis reaction [26, 27, 28].
Figure 2.
Bio-based solvents derived from glycerol.
n-Butanol production was first commercialized in the early 1900s, in the Weizmann process (ABE fermentation). Here, n-butanol, acetone and minute amounts of ethanol are produced from starch feedstock using Clostridium acetobutylicum [10, 29]. Later, fossil-based production of n-butanol became more cost-effective which led to abandonment of the Weizmann process. Today there are some ABE fermentation production units; however, most n-butanol is produced mainly from petroleum by either (1) the oxo synthesis which involves hydroformylation of propene and then hydrogenation of the afforded butraldehyde, in the presence of a rhodium or cobalt homogeneous catalysts, (2) the Reppe synthesis (which involves the treatment of propene with CO and H2O) in the presence of a catalyst such as iron or (3) a multistep, catalytic hydrogen borrowing, cascade process involving self-aldol condensation of acetaldehyde, dehydration and then hydrogenation of the resultant croton aldehyde [30].
n-Butanol has a low order of toxicity and has an energy density of 29.2 MJ/L, which is comparable to that of gasoline (32.5 MJ/L). It is also miscible with gasoline, and so it is not surprising that this alcohol is sometimes blended with gasoline to improve its properties. n-Butanol is also used as a solvent for coatings (varnishes, resins and waxes), paints and cosmetics and is an intermediate for making solvents (e.g. butyl propanoate, dibutyl ether and butyl acetate), polymer monomers (e.g. butyl acrylate and butyl vinyl ether) and plasticizers (e.g. butyl phthalates) [31].
2.2 Furfuryl alcohol
The production of furfuryl alcohol involves two stages: (1) the pentosan is first hydrolysed to pentoses, e.g. xylose, and (2) cyclohydration of the pentoses into furfuryl alcohol. The reaction is catalysed by acids such as dilute sulfuric or phosphoric acid, and the furfuryl alcohol is recovered by steam distillation and fractionation. Yields are generally between 30 and 50% [32].
Furfuryl alcohol is a solvent used in the refining of lubricating oils [33]. During the production of butadiene, an extractive distillation step is required to remove impurities [34]. Furfuryl alcohol is one of the extractive solvents that have been used for this purpose on a commercial scale, for example, at TransFuran Chemicals, USA. Furfuryl alcohol is also used as a solvent during crystallization of anthracene oils and during the modification of high phenolic molding resins to improve the corrosion resistance of the cured resin [35].
2.3 Glycerol and its derivatives
Global biodiesel production has increased from 0.78 billion (in 2000) to 32.6 billion liters by 2016 [36]. This has made large quantities of glycerol widely available, since biodiesel production generates 10,000 liters of glycerol for every 100,000 liters of fuel produced. This oversupply of glycerol, and its low toxicity, has driven many efforts to increase the portfolio of glycerol applications both directly and indirectly (by using it as a raw material to access value-added products). Because of its sweet taste, it can be used directly as a sweetener in processed foods. It is also used as a thickener and stabilizer for foods containing water and oil. Glycerol functions well as a solvent for processing cosmetics (this is where most glycerol is used) and forms part of pharmaceutical formulations to name a few [37].
More recently, glycerol has been used as a sustainable replacement for fossil-derived monoethylene glycol in purification of bioethanol by extractive distillation. Using glycerol, up to 99% purity of bioethanol is recovered [38]. Although its high viscosity and boiling point complicate reaction workups, several examples of successful Aza-Michael addition and Suzuki-Miyaura and Mizoroki-Heck reactions in glycerol have been reported [38, 39].
The conversion of glycerol leads to a variety of other products with solvent properties such as solketal, glycerol formal, glycerol carbonate, glycerol oligomers and polymers, deep eutectic solvents (DESs) as well as diols (Figure 1) [37, 40].
Solketal and glycerol formal are the products of acid-catalyzed acetone and formaldehyde reactions with glycerol, respectively [41], and currently solketal is sold commercially under the name Augeo™ SL 191. It is used as a solvent in interior-scenting products and household cleaners [42]. Another route to solketal is by metal-catalyzed condensation of glycidol with acetone [43].
Solketal is polar and has a very high boiling point (188°C), which makes it useful as a coalescent solvent in paints and inks and in controlled release systems (where gradual release of species like pesticides and drugs is required). It is a good heat transfer fluid and fuel additive, especially in gasoline and biodiesel where it favorably reduces the latter’s viscosity [41]. Its high sensitivity to acid has limited its use as a solvent for reactions.
2.3.1 Glycerol oligomers and polymers
The main route for preparing di-, tri-, tetra- and polyglycerol is by direct oligomerization or polymerization of glycerol using acid or base catalysts, such as potassium carbonate or sulfuric acid. The base catalyst is usually more efficient due to its better solubility in glycerol, albeit with poor selectivity [44]. Glycerol oligomers and polymers have hydrophilic heads which makes them useful for surfactant applications. By careful control of their length and branching during syntheses, desirable physiochemical properties can be built into them such that they can be used as lubricants, polymers and solvents. They have also been earmarked as replacement solvents for fossil-derived glycol ethers in paints, inks and cleaning agents [45].
2.3.2 Diols
In addition to methanol, ethanol and propanol [46], the hydrogenolysis of glycerol can lead to formation of ethylene glycol (EG) and propylene glycol (PG, 1,2-propanediol and 1,3-propanediol) (Figure 1) [47]. It is worth mentioning that diols can also be obtained from thermochemical conversion of fructose in the presence of homogeneous osmium and ruthenium catalysts [48] and from cellulose using a nickel-tungsten carbide catalyst [49]. Recently, Sappi Ltd. acquired Plaxica’s Xylex® technology which they plan to utilize in valorizing the hemicellulose component of their pulp processing waste, in producing, furfural and xylitol [50]. Changchun Dacheng Industrial Group operates a commercial integrated biological and thermochemical process that manufactures EG, PG and 2,3-butanediol (2,3-BDO) from starch. Ten thousand tons of 2,3-BDO are produced annually [51].
Diols serve as dehumidifying and antifreeze agents. They have important applications as monomers (in polyester production) and work as solvents in the cosmetic and coating (varnishes and waxes) industries [46, 49].
Lactates are a class of non-toxic and green solvents obtained from treating lactic acid with various alcohols, such as ethanol, propanol and butanol. Lactic acid feedstock for making these solvents can be obtained via biochemical and thermochemical routes. The latter is economical but uses toxic hydrogen cyanide and gives a racemic mixture of lactic acid, while the biological process uses microbial fermentation technology and is more selective.
Ethyl lactate is the most common of the lactate esters, and Archer Daniels Midland Company, USA, operates a commercial production plant. Ethyl lactate has excellent physical properties, including a low vapor pressure and high boiling point (151–155°C) and solvent power (Kauri-butanol value > 1000). This makes it a good replacement for halogenated solvents, acetone and toluene and an excellent solvent for solubilizing resins and polymers. As such, it is used to dissolve plastics and to remove salts from circuit boards. Ethyl lactate also dissolves grease, inks and solder paste and strips paint [52].
Fatty acid methyl esters are produced by the transesterification of triglycerides, from vegetable oils or animal fats, with methanol for biodiesel applications. However, FAMEs can also be used as bio-based solvents and have been found to possess high solvent power. When mixed with ethyl lactate, evaporation is aided post utilization in dissolution or in cleaning industrial parts [53].
3.2 Glycerol carbonate and γ-valerolactone
Glycerol carbonate can be synthesized via direct or indirect routes. With direct routes, carbon monoxide and oxygen [54] or carbon dioxide [55] is treated with glycerol in the presence of metal catalysts such as Pd and Sn, respectively. The use of CO2 is more desirable due to its abundance and lower toxicity in comparison to CO; however, this route is low yielding (7–35%). The indirect route involves carbonation of glycerol with an activated carbonation source such as urea, dimethyl carbonate or phosgene, and among these dimethyl carbonate is preferred from an industrial production perspective [56].
Due to its favorable properties which include high polarity, boiling point (110–115°C) and flash point (109°C) and low vapor pressure, glycerol carbonate has interesting applications as a polar protic solvent, electrolyte liquid carrier, detergent solvent, humectant and nail polish/gel stripper [57]. It has also been demonstrated to serve as a promising solvent in pretreatment of sugarcane bagasse [13].
γ-Valerolactone (GVL) can be produced from 5-hydroxymethylfurfural or furfural alcohol via their dehydration and hydrolysis, respectively [58]. The resultant levulinic acid can then be converted to GVL in the presence of hydrogen and a suitable catalyst [59, 60]. This therefore links the cost of GVL production to the production of hydrogen. This has resulted in the limited widespread production and use commercially. The increased number of hydrogen production plants by water electrolysis (or use of transfer hydrogenation techniques) should aid in improving the process and economics to favor GVL commercial-scale production in the near future.
The physical and chemical properties of GVL favor its application as a solvent and illuminating fuel. It has a low melting point, high boiling and flash point and low toxicity and has a characteristic herbal smell that can be used to identify leaks or spills [61]. GVL has been used as a solvent in many biomass conversion reactions. For example, it was used as a solvent in the pretreatment of lignocellulose, hydrolysis of lignocellulose and dehydration of carbohydrates to furans [61, 62]. It has also been used as solvent in cross-coupling reactions such as Sonogashira [63], Hiyama [64] and Mizoroki-Heck [65].
3.3 Cyrene™
Cyrene (dihydrolevoglucosenone or 6,8-dioxabicyclo[3.2.1]octanone) is a ketone functionality containing solvent that can be prepared in a two-step process from cellulose [66]. The common starting point in its synthesis is from levoglucosenone (LGO), which can be obtained from a variety of cellulosic starting feedstocks such as Bilberry presscake [67], corn cob [68], poplar wood [69] or bagasse [70]. LGO has been successfully obtained from cellulose [71, 72, 73], by the patented Furacell™ process discovered by Circa Group Ltd., Australia. The process gives 40% yield of LGO and has consequently been scaled up to a 50 ton/year production [74]. The next step after the production of LGO is its hydrogenation to afford Cyrene™ (Figure 3). The hydrogenation of levoglucosenone to Cyrene has been largely dominated by heterogeneous Pd catalysts [75, 76].
Figure 3.
Synthetic steps of Cyrene™ from cellulose.
Concerns over the use of toxic solvents (such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP)) in the industry have led to the exploration of Cyrene™ as a potential replacement. These dipolar aprotic solvents have very similar properties to those of Cyrene™ [77]. As a result, more examples of its use as solvent in syntheses are becoming popular. For example, metal organic frameworks that were previously prepared in DMF solvent have been successfully synthesized in Cyrene™ [78]. Cyrene™ has also been used in amide bond formation reactions [79].
3.4 Alkanes and aromatics
3.4.1 Alkanes
Furfural and hydroxymethylfuran can react with acetone (derived from fermentative processes) resulting in aldol-condensed products with longer carbon chain lengths. Subsequent hydrodeoxygenation of the aldol condensation products using a supported Pd catalyst, H2 (plus acetic and/or Lewis acid cocatalysts), produces alkanes as shown in Figure 4 [80, 81, 82, 83].
Figure 4.
Synthetic steps for straight-chain alkanes from bio-derived furan compounds.
Alkanes are useful for reactions requiring nonpolar medium because they are generally unreactive. Consequently, they have been used as reaction medium during the synthesis of drugs, pesticides and other chemicals. Their use as fuels varies depending on the length of the carbon chains. Generally C3 and C4 alkanes are used as liquefied petroleum gas for cooking and in cigarette lighters, respectively, while C5–C18 alkanes are used in gasoline, diesel and aviation fuel.
3.4.2 Benzene, toluene and xylenes
Benzene, toluene and xylene (BTX) can be derived from wood and agricultural waste [84]. Anellotech, a US-based company, has scaled up a process that converts biomass, using their Bio-TCat™ technology, into BTX mixtures. Benzene, toluene and xylene have identical properties as their fossil-derived counterparts [85]. Benzene is used in the manufacture of resins, rubber lubricants, synthetic fibers, detergents, pesticides, drugs and plastics. Toluene is used in printing and leather tanning processes and as a solvent in paint, a nail polish remover, thinners and glues, while xylene finds use as a cleaning agent, ingredient in pesticide manufacturing, disinfectants, paints, paint thinners, polishes, waxes and adhesives.
An elegant multistep route to renewable p-xylene was proposed. It begins with (1) the conversion of glucose to fructose, (2) followed by dehydration of the fructose to HMF, (3) hydrodeoxygenation of HMF to 2,5-dimethylfuran (2,5-DMF) and (4) subjecting the resultant 2,5-DMF to Diels-Alder cycloaddition with ethylene to afford the product [86].
3.4.3 Terpenes
Terpenes are a class of natural solvents obtained from essential oils found in plants. They have C5H8 isoprene units and can be acyclic, bicyclic or monocyclic; therefore, they have varying physical and chemical properties. Extraction using water hetero-azeotropic distillation at low temperatures affords terpenes, and they in turn have been utilized as green alternative solvents for the extraction of oils from microalgae [87].
D-Limonene is extracted from citrus peels and pulp by steam distillation and alkali treatment [88]. Industrially, limonene is used as a solvent in place of various halogenated hydrocarbons. By 2023, the demand of D-limonene is expected to be 65 kilotons/year [88]. It is also used as solvent to degrease and grease wool and cotton wool and in the dissolution of cholesterol stone, where its performance is better than chloroform and diethyl ether (DEE) in the latter. The catalytic isomerization and dehydrogenation of D-limonene give p-cymene, an aromatic hydrocarbon with equally good solvent properties [89].
α-Pinene is the most widely available terpenoid and is mostly found in essential oils of coniferous trees, or it can be recovered from paper pulping by-products, i.e. from crude sulphate turpentine [90]. Alpha-pinene is used as a household cleaning solvent and repellent for insects and in the production of perfumes. It also have medicinal properties as an anti-inflammatory and antibiotic agent.
3.5 Ethers
Bio-derived ethers are produced by the dehydration of bio-alcohols, mainly ethanol and methanol to form diethyl ether and dimethyl ether, respectively. These ethers are usually used as fuel additives to improve its octane rating and reduce emissions (NOx and ozone) and engine wear.
2-Methyltetrahydrofuran (2-MeTHF) is a biodegradable, non-toxic, non-ozone-depleting, easy-to-recycle ether solvent with a good preliminary toxicology report [91]. It is produced from either furfural or levulinic acid via catalytic processes. For instance, the successive hydrogenation of furfural over Ni-Cu, Fe-Cu, Cu-Zn or Cu-Cr produces 2-MeTHF as illustrated in Figure 5 [92, 93].
Figure 5.
The successive hydrogenation of furfural to 2-methyltetrahydrofuran.
The first two hydrogenations have been reported to quantitatively convert furfural alcohol to 2-methylfuran using Ni-based catalysts followed by 2-methylfuran conversion over a Cu-Zn catalyst. 2-MeTHF can also be prepared from levulinic acid via consecutive hydrogenation and dehydrogenation steps. Here, Ru-based catalysts are the most active.
Pfizer, USA, has reported the application of 2-MeTHF as a solvent in two-phase reactions due to the poor solubility of water in 2-MeTHF [94]. This bio-derived solvent has also been used in place of dichloromethane (that has unfavourable environmental effects) because of its low boiling point, which makes it difficult to contain on a large scale. Using 2-MeTHF, high yields of product were afforded for amidations, alkylations and nucleophilic aromatic substitutions reactions.
Another pharmaceutical company, Actelion Pharmaceuticals Ltd. in Switzerland, uses 2-MeTHF as solvent in the synthesis of 5-phenylbicyclo-[2.2.2]oct-5-en-2-one [95], an intermediate during the preparation of an important preclinical candidate. Furthermore, the reaction was successfully upscaled to kilogram scale, and the reaction still gave excellent yields (98%) in 2-MeTHF.
Ionic liquids (ILs), defined here as materials that are made up of cations and anions (salts) which melt at or below 100°C, evolved from the nineteenth century. This field started with a report by Paul Walden, in which he studied the physical properties of ethylammonium nitrate ([EtNH3][NO3]), a salt which melted at around 14°C [96]. Ionic liquids are commonly formed through the combination of an organic cation (usually heterocyclic), such as dialkylimidazolium, and either an inorganic or organic anion (such as halides or methanesulfonate) [97]. The advantage with ionic liquids is their low vapor pressure, meaning the risk of atmospheric contamination and related health issues are reduced by using these solvents. It is for this particular reason that they are viewed as green solvents [98]; however, low volatility alone is not the only property that makes ionic liquids green. For instance, toxic and non-biodegradable ionic liquids will not be referred to as a green solvent even though they have negligible volatility [97]. In this regard, ionic liquids composed of bio-derived components have the added advantage and are outstanding candidates as sustainable and green solvents.
4.1 Sugar-based ionic liquids
Since the depolymerization of hard-to-dissolve carbohydrate polymers can be achieved using ILs, it would be beneficial to develop sugar-based ILs with the aim of employing these in a ‘closed-loop’ carbohydrate polymer depolymerization process [99]. Some sugar-based ionic liquids which have potential in this regard have already been synthesized, even though they have been used for various other processes. The glucose-linked 1,2,3-triazolium ionic liquids were synthesized by copper(I)-catalysed regioselective cycloaddition of a glucose azide to a glucose alkyne, followed by quaternization with methyl iodide (Figure 6) [100]. The ILs were used as reusable chiral solvents and ligands in copper(I)-catalysed amination of aryl halides with aqueous ammonia. The triazolium salt affords the compound in its liquid state at room temperature, and hence the compound can be used as a solvent, while the free hydroxyl groups of the glucose moiety aids in stabilizing the copper(I) species during the reaction.
Figure 6.
Glucose-based ionic liquids [(A and B) glucose-tagged triazolium ILs; (C) glucopyranoside-based IL].
Methyl-D-glucopyranoside has also been used to synthesize an ionic liquid with promising solvent potential [101]. The synthetic sequence involved uses thexyldimethylsilyl chloride (TDSCl) to protect the hydroxyl at the primary position. The other secondary hydroxyl groups were converted to methyl ethers followed by reduction of the anomeric position and further deprotection of the primary hydroxyl. After deprotection of the primary hydroxyl group, it was then converted to a triflate to form an intermediate. This triflate intermediate finally underwent a nucleophilic substitution reaction using diethyl sulphide to afford an ionic liquid, with a triflate anion and a sulfonium cation, which was a liquid at room temperature (Figure 6).
Handy et al. have used fructose to synthesize room temperature ionic liquids [102]. In their synthetic protocol, copper carbonate, ammonia and formaldehyde were used to ring-close fructose and form hydroxymethylene imidazole. This imidazole was then taken through a series of alkylation steps (with 1-bromobutane followed by iodomethane) to form an imidazolium cation. Anion metathesis was performed to give a series of room temperature ionic liquids (Figure 7), which were used as recyclable solvents for Mizoroki-Heck cross-coupling of aryl iodides with alkenes.
Figure 7.
ILs based on pentoses [(A) fructose-based ILs; (B) arabinose-based ILs].
An arabinose-based imidazolium IL was synthesized in 2018 starting with 2,3,5-tri-O-benzyl-D-arabinofuranose [103]. The pentofuranoside starting material was prepared by benzylating all the hydroxyl groups of D-arabinose, except the hydroxyl group on the carbon adjacent the ring oxygen atom. The free hydroxyl group was then reacted with propane-1,3-diyldioxyphosphoryl chloride in the presence of 1-methylimidazole to form a mixture of anomeric phosphates. This was then reacted with 1-methylimidazolium chloride and trimethylsilyl triflate, in catalytic amounts, to give a pure anomeric ionic liquid with a chloride anion. Anion metathesis reactions gave two additional ionic liquids (Figure 7), which were used as co-solvents in the synthesis of alcohols from aromatic aldehydes.
4.2 Alkaloid-based ionic liquids
Ionic liquids which contain ampicillin as active pharmaceutical ingredients were developed by Ferraz et al., by neutralizing basic ammonia solutions of ampicillin with different organic cation hydroxides. These ampicillin-based ILs may be useful in the development of bioactive materials [104]. A chiral IL derived from ephedrine was synthesized by Wasserscheid et al. N-methylephedrine was synthesized from ephedrine and alkylated with dimethyl sulphate followed by ion exchange to form the IL, with a melting point of 54°C [105]. Heckel et al. reported the synthesis of ionic liquids derived from nicotine by the quaternization of the pyridine ring of nicotine with methyl iodide and ethyl bromide. The resulting chiral nicotine-based ILs were examined as chiral solvating agents (Figure 8) [106].
Linoleate and oleate were used in the syntheses of four ILs with melting points below −21°C (Figure 9). Unsaturated fatty acids were initially taken through neutralization reactions with NaOH followed by ion exchange with either tetraoctylammonium or methyltrioctylammonium chloride. The ILs were then successfully used as solvents in the extraction of metal ions from aqueous solutions [107].
Figure 9.
Anions and cations used in the syntheses of lipid-based ILs.
Kwan et al. also synthesized ILs using lipids through alkylating a tertiary amine (Figure 10). The lipids used in this instance were methyl oleate and methyl stearate. In a third instance, cyclopropanated oleic acid methyl ester synthesized the reaction of the double bond of the oleate with diiodomethane, and diethylzinc was used to alkylate the tertiary amine. After reacting the obtained alkyl iodide with the imidazoles, anion exchange of the iodide with bistriflimide gave imidazolium bistriflimide ILs [108].
Deep eutectic solvents are analogous to ILs in the sense that they possess similar properties of low melting point and non-volatility, but they are, however, two different types of solvent systems. Unlike ILs, which are made up of one type of discrete cation and anion [17], DESs are formed from an eutectic mixture of a hydrogen bond acceptor (HBA), mostly quaternary ammonium salts, and a metal salt or hydrogen bond donor (HBD). The mixture forms a eutectic phase which has a lower melting point than the individual components [109]. There is a charge delocalization created through hydrogen bonding between, for example, a halide anion of the HBA and the HBD which causes the decrease in the melting point [18]. DESs are usually formed from relatively inexpensive bio-based components which makes them biodegradable and affordable [17]. Abbott et al. initially developed DESs based on choline chloride and zinc chloride as cheaper alternatives to imidazolium-based ionic liquids, which would make them readily accessible for bulk applications in syntheses. These new solvents were made by heating mixtures of the choline chloride and zinc chloride in molar ratios of 1:1, 1:2 and 1:3 until clear colorless liquids were obtained, with the 1:2 mixture giving the lowest freezing point of 25°C [110]. Choline is a provitamin which is derived from lecithin, found in plants and animal organs [111]. As such, choline-derived DESs are bio-based solvents, particularly where it is paired up with bio-sourced HBDs such as lactic acid, levulinic acid, glycerol and sugars. On a large scale, choline is produced by a single-step reaction between HCl, ethylene oxide and trimethylamine [17].
DESs based on urea (Figure 11) were prepared by mixing choline chloride (m.p. 302°C) and urea (m.p. 133°C) in different molar ratios. This showed that a eutectic phase occurs at a choline to urea ratio of 2. This DES has a very low freezing point of 12°C, which was significantly lower than its constituents, thus giving a room temperature solvent [112]. The choline chloride-urea DES has been used as both a catalyst and solvent for the selective N-alkylation of various aromatic primary amines. This method avoids the complexity of multiple alkylations, which is a problem encountered when polar volatile organic solvents are used. After the reaction, DES recycling by simple biphasic extraction with ethyl acetate was carried out, and the DES was reused at least five times (with just a slight loss in activity) [113]. This same group have used the choline chloride-urea DES as a solvent and catalyst for the bromination of 1-aminoanthra-9,10-quinone [114] and for the Perkin reaction [115].
Figure 11.
DES based on choline chloride and urea.
DESs based on choline chloride and glycerol or ethylene glycol have also been used as extraction solvents to remove excess glycerol from biodiesel [116, 117, 118]. Also, new choline chloride-based DESs with levulinic acid and sugar-based polyols as renewable hydrogen bond donors were synthesized. The best ratios of choline chloride (ChCl) and HBD which gave liquid DESs at room temperature are shown in Table 1 [119]. DESs based on different bio-based HBD (oxalic, lactic and malic acids) and HBA (choline chloride, betaine, alanine, glycine, histidine, proline and nicotinic acid) have also been prepared and tested as solvents for the dissolution of lignin, cellulose and starch. Majority of the resulting solvents exhibited high lignin solubility but poor cellulose solubility.
Table 1.
Novel room temperature liquid DESs derived from renewable sources [119].
This was advantageous since DESs can be used in separating lignin from cellulose [120]. DESs can be viewed as a more environmentally friendly alternative to volatile organic solvents—they are affordable, easily prepared and scalable, inflammable and also biodegradable [121].
Rising concerns over depletion of fossil reserves and the drive towards sustainable and responsible consumption of resources have presented a challenge and opportunity for scientist and engineers to work together in developing methods, technologies and processes for producing of bio-based products. These include commodity chemicals, fuels and materials of which many of the chemicals have solvent properties. As such, they have been widely used in extractions and in solvating a range of physiochemical processes and numerous consumer goods (by either dissolving, stabilizing or modifying the latter’s properties) across the manufacturing research and development landscapes. This review has contextualized and discussed some existing and emerging approaches in these areas.
Even though most bio-solvents are still volatile like their petroleum counterparts, the bio-solvents have the advantage of being biodegradable, derived from renewable resources, and their production often results in CO2 emission savings. A novel array of ionic liquids and deep eutectic solvents based on inexpensive bio-derived components has been developed, and because these solvents have low volatility, it presents a solution to the volatile organic solvent concern. Additionally, they are usually recyclable after use, with the benefit of tunability to bring about smart solvents for tailored applications.
This work was supported by the Royal Society and African Academy of Sciences, the Future Leaders—African Independent Researchers (FLAIR) Scheme (Fellowship ref.: 191779), the National Research Foundation (NRF) of South Africa (Grant numbers: 105559, 112809 and 117989) and the University of Johannesburg’s Centre for Synthesis and Catalysis.
1.Kerton FM. Alternative Solvents for Green Chemistry. Cambridge: Royal Society of Chemistry; 2009. DOI: 10.1039/9781847559524
2.Anastas PT, Levy IJ, Parent KE. Green Chemistry Education. Washington: American Chemical Society; 2009. DOI: 10.1021/bk-2009-1011.fw001
3.Curzons AD, Constable DJC, Mortimer DN, Cunningham VL. So you think your process is green, how do you know?—Using principles of sustainability to determine what is green–a corporate perspective. Green Chemistry. 2001;3:1-6. DOI: 10.1039/b007871i
4.Prat D, Wells A, Hayler J, Sneddon H, Mcelroy CR, Abou-shehada S, et al. CHEM21 selection guide of classical- and less classical-solvents. Green Chemistry. 2016;18:288-296. DOI: 10.1039/c5gc01008j
5.Diorazio LJ, Hose DRJ, Adlington NK. Toward a more holistic framework for solvent selection. Organic Process Research and Development. 2016;20:760-773. DOI: 10.1021/acs.oprd.6b00015
6.Capello C, Fischer U, Hungerbu K. What is a green solvent ? A comprehensive framework for the environmental assessment of solvents. Green Chemistry. 2007;9:927-934. DOI: 10.1039/b617536h
7.Makhubela BCE, Darkwa J. The role of noble metal catalysts in conversion of biomass and bio-derived intermediates to fuels and chemicals. Johnson Matthey Technology Review. 2018;62(1):4-31. DOI: 10.1595/205651317X696261
8.Clark JH, Hunt AJ, Topi C, Paggiola G, Sherwood J. Sustainable Solvents Perspectives from Research, Business and International Policy. Croydon: Royal Society of Chemistry; 2017. DOI: 10.1039/9781782624035
9.Biochemtex, Crescentino Biorefinery. A New Era Begins: World’s First Advanced Biofuels Facility. ETIP Bioenergy-SABS [Internet]. 2013. Available from: http://www.etipbioenergy.eu/images/crescentino-presentation.pdf [Accessed: March 25, 2019]
10.Weizmann C. Production of Acetone and Alcohol by Bacteriological Processes 1315585; 1919
11.Nguyen NPT, Raynaud C, Meynial-salles I, Soucaille P. Reviving the Weizmann process for commercial n-butanol production. Nature Communications. 2018;9:1-8. DOI: 10.1038/s41467-018-05661-z
12.Opre JE, Bergemann EP, Henneberry M. Environmentally Friendly Solvent. 6191087 B1; 2001
13.Zhang Z, Rackemann DW, Doherty WOS, Hara IMO. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse. Biotechnology for Biofuels. 2013;6(1):1. DOI: 10.1186/1754-6834-6-153
14.Al-shaal MG, Dzierbinski A, Palkovits R. Solvent-free γ-valerolactone hydrogenation to 2-methyltetrahydrofuran catalyzed by Ru/C: A reaction network analysis. Green Chemistry. 2014;16:1358-1364. DOI: 10.1039/c3gc41803k
15.Huber GW, Cortright RD, Dumesic JA. Renewable alkanes by aqueous-phase reforming of biomass-derived oxygenates. Angewandte Chemie International Edition. 2004;43:1549-1551. DOI: 10.1002/anie.200353050
16.Anellotech Incorporated, New York, USA [Internet]. Available from: http://anellotech.com/bio-tcat%E2%84%A2-renewable-chemicals-fuels
17.Smith EL, Abbott AP, Ryder KS. Deep eutectic solvents (DESs) and their applications. Chemical Reviews. 2014;114:11060-11082. DOI: 10.1021/cr300162p
18.Domínguez de María P. Recent trends in (ligno)cellulose dissolution using neoteric solvents: Switchable, distillable and bio-based ionic liquids. Journal of Chemical Technology and Biotechnology. 2014;89(1):11-18. DOI: 10.1002/jctb.4201
19.Abengoa Bioenergy Corporation. Europe’s Largest Bioethanol Producer [Internet]. Available from: http://www.abengoa.com/export/sites/abengoa_corp/resources/pdf/en/gobierno_corporativo/informes_anuales/2005/2005_Volume1_AnnualReport_Bioenergy.pdf
20.Cellulosic Ethanol Technology. Ongoing Research and Novel Pathways’, ETIP Bioenergy-SABS [Internet]. Available from: http://www.biofuelstp.eu/cellulosic-ethanol.html#ce6 [Accessed: March 30, 2019]
21.Commercial Cellulosic Ethanol Plants in Brazil’ and ‘Cellulosic Ethanol in Canada’, ETIP Bioenergy-SABS [Internet]. Available from: http://www.etipbioenergy.eu/value-chains/products-end-use/products/cellulosic-ethanol#brazil; http://www.etipbioener
22.A Novel Commercial Method for Extracting Artemisinin: Extracting Artemisia Annua with Ethanol and Purifying Ethanolic Extracts. Scott Process Technology Ltd, [Internet]. Available from: https://www.mmv.org/sites/default/files/uploads/docs/artemisinin/06c_
24.Morone P, Cottoni L. Biofuels: Technology, economics, and policy issues. In: Handbook of Biofuels Production. 2nd ed. Duxford, UK: Woodhead Publishing; 2016
25.Hu X, Westerhof RJM, Wu L, Dong D, Li CZ. Upgrading biomass-derived furans via acid-catalysis/hydrogenation: The remarkable difference between water and methanol as the solvent. Green Chemistry. 2014;17:219-224. DOI: 10.1039/c4gc01826e
26.Bennekom JG, Venderbosch RH, Heeres HJ. Biomethanol from glycerol. In: Biodiesel-Feedstocks, Production and Applications. London, UK: IntechOpen; 2012. DOI: 10.5772/53691
27.Speers AM, Young JM, Reguera G. Fermentation of glycerol into ethanol in a microbial electrolysis cell driven by a customized consortium. Environmental Science and Technology. 2014;48(11):6350-6358. DOI: 10.1021/es500690a
28.Maglinao RL, He BB. Catalytic thermochemical conversion of glycerol to simple and polyhydric alcohols using Raney nickel catalyst. Industrial and Engineering Chemistry Research. 2011;50:6028-6033. DOI: 10.1021/ie102573m
29.Ndaba B, Chiyanzu S, Marx I. n-Butanol derived from biochemical and chemical routes: A review. Biotechnology Reports. 2015;8:1-9. DOI: 10.1016/j.btre.2015.08.001
30.Uyttebroek M, Van Hecke W, Vanbroekhoven K. Sustainability metrics of 1-butanol. Catalysis Today. 2015;239:7-10. DOI: 10.1016/j.cattod.2013.10.094
31.Mascal M. Chemicals from biobutanol: Technologies and markets. Biofuels, Bioproducts and Biorefining. 2012;6(4):483-493. DOI: 10.1002/bbb.1328
32.Grand View Research, Marketing Research and Consulting, Global Furfural Market By Application (Furfuryl Alcohol, Solvents) Expected To Reach USD 1 200.9 Million By 2020. The Global Furfural Market By Application (Furfuryl Alcohol, Solvents) Expected To Reach USD 1,200.9 Million By 2020; 2015
33.Available from: https://ihsmarkit.com/products/furfural-chemical-economics-handbook.html [Accessed: March 11, 2019–March 11, 2018], https://IhsmarkitCom/Products/Furfural-Chemical-Economics-HandbookHtml [Accessed: March 11, 2019]
34.Available from: https://www.bechtel.com/services/oil-gas-chemicals/bhts/oil-processing/furfural-refining/ [Accessed: March 11, 2019], https://WwwBechtelCom/Services/Oil-Gas-Chemicals/Bhts/Oil-Processing/Furfural-Refining/ [Accessed: March 11, 2019]
35.Available from: http://www.furan.com/furfural_applications_of_furfural.html [Accessed: March 11, 2018], http://WwwFuranCom/Furfural_applications_of_furfuralHtml [Accessed: March 11, 2018]
36.World Bioenergy Association. Global Bioenergy Statistics. 2018. Available from: https://worldbioenergy.org/uploads/181203%20WBA%20GBS%202018_hq.pdf [Accessed: April 1, 2019]
37.Pagliaro M, Rossi M. Glycerol: Properties and Production. The Future of Glycerol: New Uses of a Versatile Raw Material. Cambridge: Wiley-VCH; 2008. DOI: 10.1002/cssc.200800115
38.Gu Y, Jerome F. Glycerol as a sustainable solvent for green chemistry. Green Chemistry. 2010;12:1127-1138. DOI: 10.1039/c001628d
39.Wolfson A, Dlugy C, Shotland Y. Glycerol as a green solvent for high product yields and selectivities. Environmental Chemistry Letters. 2007;5:67-71. DOI: 10.1007/s10311-006-0080-z
40.Pagliaro M, Rossi M. Aqueous Phase Reforming. The Future of Glycerol: New Uses of a Versatile Raw Material. Cambridge: Wiley-VCH; 2008. DOI: 10.1002/cssc.200800115
41.Moity L, Benazzouz A, Molinier V, Nardello-Rataj V, Elmkaddem MK, De Caro P, et al. Glycerol acetals and ketals as bio-based solvents: Positioning in Hansen and COSMO-RS spaces, volatility and stability towards hydrolysis and autoxidation. Green Chemistry. 2015;17(3):1779-1792. DOI: 10.1039/c4gc02377c
42.Solvay. Augeo™ SL 191 [Internet]. Available from https://www.solvay.us/en/markets-and-products/featured-products/augeo.html, http://www.youliao.com.cn/Uploads/Download/Document/tds/20398_tds.PDF [Accessed: April 1, 2019]
43.Ellis JE, Lenger SR. A convenient synthesis of 3,4-dimethoxy-5-hydroxybenzaldehyde. Synthetic Communications. 1998;28(9):1517-1524. DOI: 10.1080/00397919808006854
44.Salehpour S, Dube MA. Towards the sustainable production of higher-molecular-weight polyglycerol. Macromolecular Chemistry and Physics. 2011;212:1284-1293. DOI: 10.1002/macp.201100064
45.Sutter M, Da Silva E, Duguet N, Raoul Y, Metay E, Lemaire M. Glycerol ether synthesis: A bench test for green chemistry concepts and technologies. Chemical Reviews. 2014;115(16):8609-8651. DOI: 10.1021/cr5004002
46.Perosa A, Tundo P. Selective hydrogenolysis of glycerol with Raney nickel. Industrial and Engineering Chemistry Research. 2005;44:8535-8537. DOI: 10.1021/ie0489251
47.Bricker ML, Leonard LE, Kruse TM, Vassilakis JG, Bare SR. Methods for Converting Glycerol to Propanol. 8101807 B2; 2012
48.Crabtree SP, Tyers DV. Hydrogenolysis of Sugar Feedstock; 2007
49.Ji N, Zhang T, Zheng M, Wang A, Wang H, Wang X, et al. Direct catalytic conversion of cellulose into ethylene glycol using nickel-promoted tungsten carbide catalysts. Angewandte Chemie International Edition. 2008;47:8510-8513. DOI: 10.1002/anie.200803233
50.Sappi Limited. Sappi Invests in Sugar Separations and Clean-Up Technology to Strengthen its Renewable Bio-Chemicals Offering [Internet]. 2017. Available from: https://www.sappi.com/sappi-invests-sugar-separations-and-clean-technology-strengthe
51.Ge L, Wu X, Chen J, Wu J. A new method for industrial production of 2,3-butanediol. Journal of Biomaterials and Nanobiotechnology. 2011;2:335-336. DOI: 10.1007/s002530000486
52.Archer Daniels Midland Company. Fuels and Industrials Catalogue, ADM Solvents [Internet]. 2019. p. 16. Available from: https://assets.adm.com/Products-And-Services/Industrials/ADM-Fuels-and-Industrials-Catalog.pdf [Accessed: April 6, 2019]
53.Gonnzalez YM, Thiebaud-roux YMG, De Caro P, Lacaze-Dufaure C. Fatty acid methyl esters as biosolvents of epoxy resins: A physicochemical study. Journal of Solution Chemistry. 2007;36:437-446. DOI: 10.1007/s10953-007-9126-5
54.Hu J, Gu Y, Guan Z, Li J, Mo W, Li T, et al. An efficient palladium catalyst system for the oxidative carbonylation of glycerol to glycerol carbonate. ChemSusChem. 2011;4:1767-1772. DOI: 10.1002/cssc.201100337
55.Aresta M, Dibenedetto A, Nocito F, Pastore C. A study on the carboxylation of glycerol to glycerol carbonate with carbon dioxide: The role of the catalyst, solvent and reaction conditions. Journal of Molecular Catalysis A: Chemical. 2006;257:149-153. DOI: 10.1016/j.molcata.2006.05.021
56.Ochoa-Gomez RJ, Gomez-Jimenez-Abersturi O, Ramirez-Lopez C, Belsue M. A brief review on industrial alternatives for the manufacturing of glycerol carbonate, a green chemical. Organic Process Research and Development. 2012;16:389-399. DOI: 10.1021/op200369v
57.Sonnati MO, Amigoni S, De Givenchy EPT, Darmanin T, Choulet O, Guittard F. Glycerol carbonate as a versatile building block for tomorrow: Synthesis, reactivity, properties and applications. Green Chemistry. 2013;15(2005):283-306. DOI: 10.1039/c2gc36525a
58.Clarke CJ, Tu WC, Levers O, Bröhl A, Hallett JP. Green and sustainable solvents in chemical processes. Chemical Reviews. 2018;118(2):747-800. DOI: 10.1021/acs.chemrev.7b00571
59.Amenuvor G, Makhubela BCE, Darkwa J. Efficient solvent-free hydrogenation of levulinic acid to γ-valerolactone by pyrazolylphosphite and pyrazolylphosphinite ruthenium(II) complexes. ACS Sustainable Chemistry & Engineering. 2016;4:6010-6018. DOI: 10.1021/acssuschemeng.6b01281
60.Amenuvor G, Darkwa J, Makhubela BCE. Homogeneous polymetallic ruthenium(ii)^zinc(ii) complexes: Robust catalysts for the efficient hydrogenation of levulinic acid to γ-valerolactone. Catalysis Science and Technology. 2018;8(9):2370-2380. DOI: 10.1039/c8cy00265g
61.Zhang Z. Synthesis of γ-valerolactone from carbohydrates and its applications. ChemSusChem. 2016;9(2):156-171. DOI: 10.1002/cssc.201501089
62.Zhang L, Yu H, Wang P, Li Y. Production of furfural from xylose, xylan and corncob in gamma-valerolactone using FeCl3·6H2O as catalyst. Bioresource Technology. 2014;151:355-360. DOI: 10.1016/j.biortech.2013.10.099
63.Dougan L, Tych KM, Hughes ML. Article Type a Single Molecule Approach to Investigate the Role of Hydrogen Bond Strength on Protein Mechanical Compliance and Unfolding History2014. pp. 8-10. DOI: 10.1039/b000000x
64.Ismalaj E, Strappaveccia G, Ballerini E, Elisei F, Piermatti O, Gelman D, et al. γ-Valerolactone as a Renewable Dipolar Aprotic Solvent Deriving from Biomass Degradation for the Hiyama Reaction2014. DOI: 10.1021/sc5004727
65.Strappaveccia G, Ismalaj E, Petrucci C, Lanari D, Marrocchi A, Drees M, et al. A biomass-derived safe medium to replace toxic dipolar solvents and access cleaner heck coupling reactions. Green Chemistry. 2015;17(1):365-372. DOI: 10.1039/c4gc01677g
67.Zhou L, Lie Y, Briers H, Fan J, Remón J, Nyström J, et al. Natural product recovery from bilberry (Vaccinium myrtillus L.) presscake via microwave hydrolysis. ACS Sustainable Chemistry & Engineering. 2018;6(3):3676-3685. DOI: 10.1021/acssuschemeng.7b03999
68.Zhuang G, Bai J, Wang X, Leng S, Zhong X, Wang J, et al. Role of pretreatment with acid and base on the distribution of the products obtained via lignocellulosic biomass pyrolysis. RSC Advances. 2015;5(32):24984-24989. DOI: 10.1039/c4ra15426f
69.Lu Q , Wang TP, Wang XH, Dong CQ , Zhang ZB, Ye XN. Selective production of levoglucosenone from catalytic fast pyrolysis of biomass mechanically mixed with solid phosphoric acid catalysts. BioEnergy Research. 2015;8(3):1263-1274. DOI: 10.1007/s12155-015-9581-6
70.Wang Z, Zhang Y, Liao B, Guo QX, Sui XW. Preparation of levoglucosenone through sulfuric acid promoted pyrolysis of bagasse at low temperature. Bioresource Technology. 2011;103(1):466-469. DOI: 10.1016/j.biortech.2011.10.010
71.Halpern Y, Riffer R, Briodo A. Levoglucosenone. Journal of Organic Chemistry. 1973;38(2):204-209
72.Sarotti AM, Spanevello RA, Suárez AG. An efficient microwave-assisted green transformation of cellulose into levoglucosenone. Advantages of the use of an experimental design approach. Green Chemistry. 2007;9(10):1137-1140. DOI: 10.1039/b703690f
73.Zhang H, Meng X, Liu C, Wang Y, Xiao R. Selective low-temperature pyrolysis of microcrystalline cellulose to produce levoglucosan and levoglucosenone in a fixed bed reactor. Fuel Processing Technology. 2017;167(August):484-490. DOI: 10.1016/j.fuproc.2017.08.007
75.Krishna SH, McClelland DJ, Rashke QA, Dumesic JA, Huber GW. Hydrogenation of levoglucosenone to renewable chemicals. Green Chemistry. 2017;19(5):1278-1285. DOI: 10.1039/c6gc03028a
76.Kudo S, Goto N, Sperry J, Norinaga K, Hayashi JI. Production of levoglucosenone and dihydrolevoglucosenone by catalytic reforming of volatiles from cellulose pyrolysis using supported ionic liquid phase. ACS Sustainable Chemistry & Engineering. 2017;5(1):1132-1140. DOI: 10.1021/acssuschemeng.6b02463
77.Sherwood J, De Bruyn M, Constantinou A, Moity L, McElroy CR, Farmer TJ, et al. Dihydrolevoglucosenone (Cyrene) as a bio-based alternative for dipolar aprotic solvents. Chemical Communications. 2014;50(68):9650-9652. DOI: 10.1039/c4cc04133j
78.Zhang J, White GB, Ryan MD, Hunt AJ, Katz MJ. Dihydrolevoglucosenone (Cyrene) as a green alternative to N,N-dimethylformamide (DMF) in MOF synthesis. ACS Sustainable Chemistry & Engineering. 2016;4(12):7186-7192. DOI: 10.1021/acssuschemeng.6b02115
79.Wilson KL, Murray J, Jamieson C, Watson AJB. Cyrene as a bio-based solvent for HATU mediated amide coupling. Organic and Biomolecular Chemistry. 2018;16(16):2851-2854. DOI: 10.1039/c8ob00653a
80.Sutton AD, Waldie FD, Wu R, Schlaf M, Pete’Silks LA, Gordon JC. The hydrodeoxygenation of bioderived furans into alkanes. Nature Chemistry. 2013;5(5):428-432. DOI: 10.1038/nchem.1609
81.Simakova IL, Murzin DY. Transformation of bio-derived acids into fuel-like alkanes via ketonic decarboxylation and hydrodeoxygenation: Design of multifunctional catalyst, kinetic and mechanistic aspects. Journal of Energy Chemistry. 2016;25(2):208-224. DOI: 10.1016/j.jechem.2016.01.004
82.Xia QN, Cuan Q , Liu XH, Gong XQ , Lu GZ, Wang YQ. Pd/NbOPO4 multifunctional catalyst for the direct production of liquid alkanes from aldol adducts of furans. Angewandte Chemie International Edition. 2014;53(37):9755-9760. DOI: 10.1002/anie.201403440
83.Song HJ, Deng J, Cui MS, Li XL, Liu XX, Zhu R, et al. Alkanes from bioderived furans by using metal triflates and palladium-catalyzed hydrodeoxygenation of cyclic ethers. ChemSusChem. 2015;8(24):4250-4255. DOI: 10.1002/cssc.201500907
84.Li Z, Lepore AW, Salazar MF, Foo GS, Davison BH, Wu Z, et al. Selective conversion of bio-derived ethanol to renewable BTX over Ga-ZSM-5. Green Chemistry. 2017;19(18):4344-4352. DOI: 10.1039/c7gc01188a
85.Available from: http://www.anellotech.com/technology.BTX.pdf [Accessed: March 26, 2019]
86.Williams CL, Chang CC, Do P, Nikbin N, Caratzoulas S, Vlachos DG, et al. Cycloaddition of biomass-derived furans for catalytic production of renewable p-xylene. ACS Catalysis. 2012;2(6):935-939. DOI: 10.1021/cs300011a
87.Tanzi CD, Vian MA, Ginies C, Elmaataoui M, Chemat F. Terpenes as green solvents for extraction of oil from microalgae. Molecules. 2012;17(7):8196-8205. DOI: 10.3390/molecules17078196
88.John I, Muthukumar K, Arunagiri A. A review on the potential of citrus waste for D-limonene, pectin, and bioethanol production. International Journal of Green Energy. 2017;14(7):599-612. DOI: 10.1080/15435075.2017.1307753
89.Martin-Luengo MA, Yates M, Rojo ES, Huerta Arribas D, Aguilar D, Ruiz Hitzky E. Sustainable p-cymene and hydrogen from limonene. Applied Catalysis A: General. 2010;387(1-2):141-146. DOI: 10.1016/j.apcata.2010.08.016
90.Deepthi Priya K, Petkar M, Chowdary GV. Bio-production of aroma compounds from alpha pinene by novel strains. International Journal of Biological Sciences and Applications. 2015;2(2):15-19
91.Antonucci V, Coleman J, Ferry JB, Johnson N, Mathe M, Scott JP, et al. Toxicological assessment of 2-methyltetrahydrofuran and cyclopentyl methyl ether in support of their use in pharmaceutical chemical process development. Organic Process Research and Development. 2011;15(4):939-941. DOI: 10.1021/op100303c
92.Zhu YL, Xiang HW, Li YW, Jiao H, Wu GS, Zhong B, et al. A new strategy for the efficient synthesis of 2-methylfuran and γ-butyrolactone. New Journal of Chemistry. 2003;27(2):208-210. DOI: 10.1039/b208849p
93.Teng BT, Zhu YL, Li Y, Xiang HW, Zheng HY, Zhao GW, et al. Effects of calcination temperature on performance of Cu–Zn–Al catalyst for synthesizing γ-butyrolactone and 2-methylfuran through the coupling of dehydrogenation and hydrogenation. Catalysis Communications. 2004;5(9):505-510. DOI: 10.1016/j.catcom.2004.06.005
94.Brown Ripin DH, Vetelino M. 2-Methyltetrahydrofuran as an alternative to dichloromethane in 2-phase reactions. Synlett. 2003;34(15):2353. DOI: 10.1055/s-2003-42091
95.Funel JA, Schmidt G, Abele S. Design and Scale-Up of Diels À Alder Reactions for the Practical Synthesis of 5-Phenylbicyclo [2.2.2]oct-5-en-2-one2011. pp. 1420-1427
96.Wilkes JS. A short history of ionic liquids—From molten salts to neoteric solvents. Green Chemistry. 2002;4:73-80. DOI: 10.1039/b110838g
97.Plechkova NV, Seddon KR. Applications of ionic liquids in the chemical industry. Chemical Society Reviews. 2008;37:123-150. DOI: 10.1039/b006677j
98.Sheldon RA. Green solvents for sustainable organic synthesis: State of the art. Green Chemistry. 2005;7:267-278. DOI: 10.1039/b418069k
99.Hulsbosch J, De Vos DE, Binnemans K, Ameloot R. Biobased ionic liquids: Solvents for a green processing industry? ACS Sustainable Chemistry & Engineering. 2016;4:2917-2931. DOI: 10.1021/acssuschemeng.6b00553
100.Jha AK, Jain N. Synthesis of glucose-tagged triazolium ionic liquids and their application as solvent and ligand for copper (I) catalyzed amination. Tetrahedron Letters. 2013;54(35):4738-4741. DOI: 10.1016/j.tetlet.2013.06.114
101.Poletti L, Chiappe C, Lay L, Pieraccini D, Russo G. Glucose-derived ionic liquids: Exploring low-cost sources for novel chiral solvents. Green Chemistry. 2007;9:337-341. DOI: 10.1039/b615650a
102.Handy ST, Okello M, Dickenson G. Solvents from biorenewable sources: Ionic liquids based on fructose. Organic Letters. 2003;5(14):2513-2515. DOI: 10.1021/ol034778b
103.Chiappe C, Marra A, Mele A. Synthesis and applications of ionic liquids derived from natural sugars. In: Rauter AP, Vogel P, Queneau Y, editors. Carbohydrates and Sustainable Development II—A Mine for Functional Molecules and Materials. Berlin: Springer-Verlag Berlin Heidelberg; 2010. DOI: 10.1007/128_2010_47
104.Ferraz R, Branco C, Marrucho IM, Rebelo PN, Nunes M, Prud C. Development of novel ionic liquids based on ampicillin. Medicinal Chemistry Communications. 2012;3:494-497. DOI: 10.1039/c2md00269h
105.Wasserscheid P, Bolm C. Synthesis and properties of ionic liquids derived from the ‘chiral pool’. Chemical Communications. 2002;1(3):200-201. DOI: 10.1039/B109493A
106.Heckel T, Winkel A, Wilhelm R. Chiral ionic liquids based on nicotine for the chiral recognition of carboxylic acids. Tetrahedron: Asymmetry. 2013;24(18):1127-1133. DOI: 10.1016/j.tetasy.2013.07.021
107.Parmentier D, Metz SJ, Kroon MC. Tetraalkylammonium oleate and linoleate based ionic liquids: Promising extractants for metal salts. Green Chemistry. 2013;15:205-209. DOI: 10.1039/c2gc36458a
108.Kwan ML, Mirjafari A, Mccabe JR, Brien RAO, Essi DF, Baum L, et al. Synthesis and thermophysical properties of ionic liquids: Cyclopropyl moieties versus olefins as Tm-reducing elements in lipid-inspired ionic liquids. Tetrahedron Letters. 2013;54(1):12-14. DOI: 10.1016/j.tetlet.2012.09.101
109.Calvo FG, María F, Monteagudo J. Green and bio-based solvents. Topics in Current Chemistry. 2018;376(18):1-40. DOI: 10.1007/s41061-018-0191-6
110.Abbott AP, Capper G, Davies DL, Munro HL, Rasheed RK. Preparation of novel, moisture-stable, Lewis-acidic ionic liquids containing quaternary ammonium salts with functional side chains. Chemical Communications. 2001;1(19):2010-2011. DOI: 10.1039/b106357j
111.Zeisel SH. A brief history of choline. Annals of Nutrition and Metabolism. 2012;61:254-258. DOI: 10.1159/000343120
112.Abbott AP, Capper G, Davies DL, Rasheed RK, Tambyrajah V. Novel solvent properties of choline chloride/urea mixtures. Chemical Communications. 2003;1(1):70-71
113.Singh B, Lobo H, Shankarling G. Selective N-alkylation of aromatic primary amines catalyzed by bio-catalyst or deep eutectic solvent. Catalysis Letters. 2011;141:178-182. DOI: 10.1007/s10562-010-0479-9
114.Phadtare SB, Shankarling GS. Halogenation reactions in biodegradable solvent: Efficient bromination of substituted 1-aminoanthra-9,10-quinone in deep eutectic solvent (choline chloride: Urea). Green Chemistry. 2010;12:458-462. DOI: 10.1039/b923589b
115.Pawar PM, Jarag KJ, Shankarling GS. Environmentally benign and energy efficient methodology for condensation: An interesting facet to the classical Perkin reaction. Green Chemistry. 2011;13:2130-2134. DOI: 10.1039/c0gc00712a
116.Shahbaz K, Mjalli FS, Hashim MA, ALNashef IM. Using deep eutectic solvents for the removal of glycerol from palm oil-based biodiesel. Journal of Applied Sciences. 2010;10(24):3349-3354. DOI: 10.3923/jas.2010.3349.3354
117.Shahbaz K, Mjalli FS, Hashim MA, Alnashef IM. Eutectic solvents for the removal of residual palm oil-based biodiesel catalyst. Separation and Purification Technology. 2011;81(2):216-222. DOI: 10.1016/j.seppur.2011.07.032
118.Ho KC, Shahbaz K, Mjalli FS. Removal of glycerol from palm oil-based biodiesel using new ionic liquids analogues. Journal of Engineering Science and Technology. 2015;10(1):98-111
119.Maugeri Z, Domı P. Novel choline-chloride-based deep-eutectic-solvents with renewable hydrogen bond donors: Levulinic acid and sugar-based polyols. RSC Advances. 2012;2:421-425. DOI: 10.1039/c1ra00630d
120.Francisco M, Van Den Bruinhorst A, Kroon MC. New natural and renewable low transition temperature mixtures (LTTMs ): Screening as solvents for lignocellulosic biomass processing. Green Chemistry. 2012;14:2153-2157. DOI: 10.1039/c2gc35660k
121.Ge X, Gu C, Wang X, Jiangping T. Deep eutectic solvents (DESs)-derived advanced functional materials for energy and environmental applications: Challenges, opportunities, and future vision. Journal of Materials Chemistry A: Materials for Energy and Sustainability. 2017;5:8209-8229. DOI: 10.1039/C7TA01659J
Written By
Novisi K. Oklu, Leah C. Matsinha and Banothile C.E. Makhubela
Submitted: 05 February 2019Reviewed: 24 April 2019Published: 04 November 2019
Open access peer-reviewed chapter
