Paula Berton

A platform for more sustainable chitin films from an ionic liquid process

A versatile platform for the preparation of chitin films with tunable strength, morphology, and efficacy of application has been designed from an ionic liquid process for the production of more sustainable high value materials. Films were prepared by a simple casting method from a solution of chitin in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). The chitin source, the loading in ionic liquid, and the drying methods defined film properties such as strength, porosity, and water absorbency. Only chitin directly extracted from shrimp shells using the ionic liquid (rather than commercially available chitin) could be used to cast films strong enough to be handled and dried. The optimal loading of chitin in the ionic liquid was determined to be 2.5 wt% and different drying methods led to different film properties (e.g., hard and rigid vs. soft and porous). As an exemplary application, loading and release of a model drug (caffeine) was investigated. Interestingly, a burst release of the majority of the caffeine was observed in the first 20 minutes, followed by slow release of the remainder. Although more investigations are needed, the chitin film platform can be thought of as an attractive new tool in the development of packaging materials, biomedical devices, and absorbent materials (M. Rinaudo, Prog. Polym. Sci., 2006, 31, 603–632) made from one of Natures most abundant polymers.

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

BackgroundBiomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration.ResultsWe evaluated a commercially available PV system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that >99.9 wt% [C2C1Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses.ConclusionsThese findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.

Scaling-Up Ionic Liquid-Based Technologies: How Much Do We Care About Their Toxicity? Prima Facie Information on 1-Ethyl-3-Methylimidazolium Acetate

The potential of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) to dissolve a variety of biopolymers such as cellulose and chitin, makes it an attractive candidate for scaled-up industrial utilization. In fact, the first steps towards its use at industrial scale have been taken. This increases the urgency to fill the knowledge gaps in its toxicity and environmental impact in order to predict and control its environmental fate. In this mini-review, we discuss the available literature surrounding this key IL. The literature (through the analysis of toxicity of the anion and the cation separately) suggests that [C2mim][OAc] is a relatively safe choice for industrial applications. However, because the IL should be considered as a compound, with unique properties arising from the interactions between the ions, comprehensive toxicity information for this particular IL is still required. To decide, prima facie, if this IL is toxic or not, evaluation of its influence on human health and ecotoxicity is needed prior to its large scale utilization. We chose in this mini-review to focus on toxicity surrounding this IL and evaluate what is known and what is not. Here with all the information in hand, we hope that the urgent need for [C2mim][OAc] toxicological assessment before it can be used in numerous technologies is highlighted. In the near future, we expect that the assessment of toxicity and environmental fate and impact can be integrated directly into any research into the industrial utilization of this IL and any others contemplated for industrial application.

Transdermal Bioavailability in Rats of Lidocaine in the Forms of Ionic Liquids, Salts, and Deep Eutectic

Tuning the bioavailability of lidocaine was explored by its incorporation into the ionic liquid lidocainium docusate ([Lid][Doc]) and the deep eutectic Lidocaine·Ibuprofen (Lid·Ibu) and comparing the transdermal absorption of these with the crystalline salt lidocainium chloride ([Lid]Cl). Each form of lidocaine was dissolved in a vehicle cream and topically applied to Sprague-Dawley rats. The concentrations of the active pharmaceutical ingredients (APIs) in blood plasma were monitored over time as an indication of systemic absorption. The concentration of lidocaine in plasma varied between applied API-based creams, with faster and higher systemic absorption of the hydrogen bonded deep eutectic Lid·Ibu than the absorption of the salts [Lid]Cl or [Lid][Doc]. Interestingly, a differential transdermal absorption was observed between lidocaine and ibuprofen when Lid·Ibu was applied, possibly indicating different interactions with the tissue components.

The effects of pH on the partitioning of aromatic acids in a polyethylene glycol/dextran aqueous biphasic system

ABSTRACT Distribution ratios of acidic, neutral, and basic compounds were determined in polyethylene glycol (PEG)-6000/Dextran-75000 aqueous biphasic systems (ABSs) at incremental pH values. The nature of the solute species present at each pH was identified using speciation diagrams, and it was determined that the distribution ratios were related to their charge, with maximum distribution to the upper PEG-rich phase when the neutral species were dominant. The results suggest that this ABS is tunable with simple modifications of pH leading to increasing selectivity for specific target solutes.

Polyoxometalate catalysts for biomass dissolution: understanding and design

Abstract The use of polyoxometalate catalysts for selective delignification of biomass presents a possible route toward using ionic liquids (ILs) to efficiently obtain high-molecular weight biopolymers from biomass. Rapid progress in this area will depend on recognizing and using the link with already well-developed inorganic chemistry in ILs pursued outside the field of biomass processing. Here, we use crystal structures determined from single crystal X-ray diffraction to better understand the behavior of [PV2Mo10O40]5-, a polyoxometalate catalyst known for its ability to promote selective delignification of biomass in the IL 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). The crystal structure of [C2mim]5[PV2Mo10O40]·THF shows the formation of cationic shells around the anions which are likely representative of the interactions of this catalyst with [C2mim][OAc] itself. The reaction of NH4VO3 with [C2mim][OAc] is explored to better understand the chemistry of vanadium(V), which is critical to redox catalysis of [PV2Mo10O40]5-. This reaction gives crystals of [C2mim]4[V4O12], showing that this IL forms discrete metavanadates which are obtained from aqueous solutions in a specific pH range and indicating that the basicity of [OAc]- dominates the speciation of vanadium (V) in this IL.

Porphyrinic Ionic Liquid Dyes: Synthesis and Characterization

Abstract Four porphyrinic ionic liquids and four higher melting salts (>100 °C) were synthesized as potential photosensitizers from highly symmetric porphyrins by introducing alkyl chains and exchanging anions to tune their solubility and singlet oxygen generation capability. Among the synthesized compounds was 5,10,15,20‐tetra(4‐dodecylpyridinum)porphyrin tetrakis‐bis(trifluoromethylsulfonyl)‐amide, a room‐temperature ionic liquid that could be crystallized as a solvate with nitrobenzene.

Ionic Liquids for Sustainable Chemical Processes

The (re)discovery of ionic liquids (ILs) as solvents in the 1990s drove the perception that this group of low-melting liquid salts are “green,” “nontoxic,” and “environmentally friendly.” However, these overgeneralizations resulted in the antagonistic perception that “ILs are toxic.” In this article, we discuss the hype and antihype cycles that affect the view of the field as a whole and restricts the choice of these liquids for certain applications. We also present a case study of the IL-based sustainable technology of biomass dissolution that allows recovery of a variety of biopolymers and their subsequent use in preparation of different materials.