Amino Acid-Based Deep Eutectic Solvents in Biomass Processing - Recent Advances

Abstract

The use of non-conventional solvent systems, such as deep eutectic solvents (DES), for biomass processing is a growing interest. DES are formed by two or more components, usually solids at room temperature, which can interact with each other via hydrogen bonding, from a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), resulting in a liquid phase. The most studied HBA in the literature is choline chloride with several HBD and their use have been extensively reviewed. However, other abundant and natural HBA can be successfully applied on the preparation of different DES, e.g., amino acids. These amino acid-based DES have been used in biomass pretreatment, providing the fractionation of the main macromolecular components by lignin solubilization. In addition, amino acid-based DES can be applied in biomass chemical conversion to obtaining platform chemicals such as furanic derivatives. Bearing this in mind, this review focuses on exploring the use of amino acid-based DES on biomass processing, from pretreatment to chemical conversion.

Dissolving and Efficient Fractionation of Chitin and Synchronous Preparation of Calcium Lactate from Crayfish Shell Waste Using Amino Acid-Based Deep Eutectic Solvents

“…Given this, the purpose of our research was to develop an alkaline DESs system to simultaneously achieve the dissolution, extraction of chitin, and preparation of calcium lactate (CL). Chitin is a natural polymer of high molecular weight and high crystallinity, so the solvent systems of chitin must have high ionic strength and the ability to break hydrogen bonds. , Therefore, we chose 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as one of the DESs components, which can easily form superbasic cations due to its high proton trapping ability. Amino acids, which are degradable, nontoxic, renewable, readily available, and abundantly stored, can act as proton donors and turn into anions. − In addition, cheap and readily available urea contains hydrogen bonding functional groups that can prevent the aggregation of chitin molecules and promote chitin dissolution.…”

“…Chitin is a natural polymer of high molecular weight and high crystallinity, so the solvent systems of chitin must have high ionic strength and the ability to break hydrogen bonds. 44,45 Therefore, we chose 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as one of the DESs components, which can easily form superbasic cations due to its high proton trapping ability. Amino acids, which are degradable, nontoxic, renewable, readily available, and abundantly stored, can act as proton donors and turn into anions.…”

Understanding the Interactive Relationship between Aliphatic Series Deep Eutectic Solvents and Lignocellulosic Dimer Model Compounds

“…However, these conventional techniques may significantly aggravate cellulose and excessive hemicellulose fragmentation or cause irreversible degradation of lignin with significantly condensed structures. Deep eutectic solvents (DESs) are supposed to deconstruct lignocellulosic biomass rationally as new solvents, possessing quite a few advantages, such as designability, moderation, stability, and so on. , DESs generally are obtained by the interactions between hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs), including mostly two and three constituents. , Recently, choline chloride (ChCl) as an HBA has gained extensive attention in the fractionation of lignocellulosic biomass due to its biocompatibility, low cost, and reasonable affinity for lignocellulosic biomass. , At the same time, various aliphatic organics as the HBD (such as monocarboxylic acids, dicarboxylic acids, hydroxy acids, and polyols) are constantly being developed for different demands in the deconstruction of lignocellulosic biomass. , Additionally, mechanisms of interaction between DESs and lignocellulose are becoming increasingly known to researchers. For instance, Zhang et al prepared DESs from ChCl, acetic acid, lactic acid, and glycerol HBD and evaluated them for the treatment of lignocellulosic biomass and binding interaction between different types of DESs with softwood lignin (predominantly guaiacyl (G) type) and hardwood lignin (a mixture of guaiacyl and syringyl (GS)), differing significantly.…”

“…9,10 At the same time, various aliphatic organics as the HBD (such as monocarboxylic acids, dicarboxylic acids, hydroxy acids, and polyols) are constantly being developed for different demands in the deconstruction of lignocellulosic biomass. 11,12 Additionally, mechanisms of interaction between DESs and lignocellulose are becoming increasingly known to researchers. For instance, Zhang et al 13 prepared DESs from ChCl, acetic acid, lactic acid, and glycerol HBD and evaluated them for the treatment of lignocellulosic biomass and binding interaction between different types of DESs with softwood lignin (predominantly guaiacyl (G) type) and hardwood lignin (a mixture of guaiacyl and syringyl (GS)), differing significantly.…”

Effect of Isomerization and Copolymerization of Itaconic Anhydride During the Synthesis of Renewable Monomers Using Vegetable Oils

“…Therefore, renewable raw materials are an alternative for the syntheses of new monomers, polymers, solvents, and so on. [1][2][3][4] The 2-methylenesuccinic anhydride, which is also known as itaconic anhydride (ITA) is a derivative of itaconic acid and presents elevated reactivity. 5 The main production of itaconic acid is by the fermentation of carbohydrates.…”