Development of new bio-based solvents via dialkyl carbonate chemistry

This work aimed to synthesise new bio-based solvents from bio-based platform molecules and dimethyl carbonate (DMC) as alternatives for traditional solvents. This work extended the scope of the DMC chemistry to including acid catalysts. Hansen Solubility Parameters in Practice (HSPiP) software was utilised as an effective tool to identify suitable bio-based solvents candidates

Acid-catalysed carboxymethylation, methylation and dehydration of alcohols and phenols with dimethyl carbonate under mild conditions

Dimethyl carbonate (DMC) chemistry has been extended to include acid-catalysed reactions of different aliphatic alcohols and phenols. For the first time, p-toluenesulfonic acid (PTSA), H2SO4, AlCl3 and FeCl3 have been shown to aid carboxymethylation for primary aliphatic alcohols at catalytic loadings with quantitative conversion and selectivity. For carboxymethylation of secondary alcohols, stoichiometric PTSA and catalytic AlCl3 both gave quantitative conversion and selectivity. Stoichiometric FeCl3 and H2SO4 promoted dehydration of linear aliphatic alcohols. Additionally FeCl3 catalysed methylation of cyclohexanol, whilst AlCl3 resulted in methylation of phenolic compounds. This research expands the range of potential application for DMC in green chemistry

Challenges in the development of bio-based solvents : A case study on methyl(2,2-dimethyl-1,3-dioxolan-4-yl)methyl carbonate as an alternative aprotic solvent

Many traditional solvents have drawbacks including sustainability and toxicity issues. Legislations such as REACH is driving the move towards less hazardous chemicals and production processes. Therefore, safer bio-based solvents need to be developed. Herein, a 10 step method has been proposed for the development of new bio-based solvents that utilise a combination of in silico modelling of Hansen solubility parameters (HSPs), experimental Kamlet-Abboud-Taft parameters, selection of green synthetic routes followed by applications testing and toxicity measurements. The challenges that the chemical industry face in the development of new bio-based solvents are highlighted through a case study on methyl (2,2-dimethyl-1,3-dioxolan-4-yl) methyl carbonate (MMC) which can be synthesised from glycerol. Although MMC is an attractive candidate as a replacement solvent, simply being bio-derived is not enough for a molecule to be regarded as green. The methodology of solvent development described here is a broadly applicable protocol that will indicate if a new bio-based solvent is functionally proficient, but will also highlight the importance of early stage Kamlet-Abboud-Taft parameters determination and toxicity testing in the development of a green solvent

A novel unambiguous strategy of molecular feature extraction in machine learning assisted predictive models for environmental properties

Environmental properties of compounds provide significant information in treating organic pollutants, which drives the chemical process and environmental science toward eco-friendly technology. Traditional group contribution methods play an important role in property estimations, whereas various disadvantages emerge in their applications, such as scattered predicted values for certain groups of compounds. In order to address such issues, an extraction strategy for molecular features is proposed in this research, which is characterized by interpretability and discriminating power with regard to isomers. Based on the Henry's law constant data of organic compounds in water, we developed a hybrid predictive model that integrates the proposed strategy in conjunction with a neural network framework. The structure of the predictive model is optimized using cross-validation and grid search to improve its robustness. Moreover, the predictive model is improved by introducing the plane of best fit descriptor as input and adopting k-means clustering in sampling. In contrast with reported models in the literature, the developed predictive model demonstrates improved generality, higher accuracy, and fewer molecular features used in its development

3-Methoxybutan-2-one as a sustainable bio-based alternative to chlorinated solvents

Methylation of acetoin with dimethyl carbonate was performed in a sustainable one-step process, with improved process mass intensity (PMI) and atom economy compared to previously published methods. The resulting product, 3-methoxybutan-2-one (MO) was successfully evaluated as a bio-based solvent, while both Kamlet–Taft solvatochromic parameters and Hansen solubility parameters demonstrate its potential viability in the substitution of chlorinated solvents. MO exhibited a low peroxide forming potential and a negative Ames mutagenicity test and was successfully used as a solvent in a Friedel–Crafts acylation (79% yield compared to 77% in dichloromethane) and for N-alkylations. MO is a renewable oxygenated solvent, with the potential ability to substitute carcinogenic halogenated solvents in some applications

DFT and experimental analysis of aluminium chloride as a Lewis acid proton carrier catalyst for dimethyl carbonate carboxymethylation of alcohols

The Lewis acid catalysed mechanism of dimethyl carbonate (DMC) mediated carboxymethylation of alcohol was investigated experimentally and through computational chemistry methods including density functional theory (DFT). Experimental data showed that catalytic loading of AlCl3 enabled the quantitative carboxymethylation of octanol in less than 20 h, while in the absence of a catalyst only trace product was observed. The geometry of the identified transition states and related energy barriers indicate that the activation energies in AlCl3 catalysed pathways are significantly lower than those in catalyst-free pathways. Theoretical quantum chemistry methods were utilised to explore and analyse the complex of DMC with AlCl3. Natural bond orbital theory analysis and molecular orbital analysis demonstrated that the dipole present in Al-Cl covalent bonding plays a vital role in assisting the proton-transfer process. Most importantly, the reaction mechanism disclosed in this research can aid in the exploration of new Lewis acid catalysed processes in the field of dialkyl carbonate chemistry

Innate Lymphoid Cells: Emerging Players in Pancreatic Disease

Common pancreatic diseases have caused significant economic and social burdens worldwide. The interstitial microenvironment is involved in and plays a crucial part in the occurrence and progression of pancreatic diseases. Innate lymphoid cells (ILCs), an innate population of immune cells which have only gradually entered our visual field in the last 10 years, play an important role in maintaining tissue homeostasis, regulating metabolism, and participating in regeneration and repair. Recent evidence indicates that ILCs in the pancreas, as well as in other tissues, are also key players in pancreatic disease and health. Herein, we examined the possible functions of different ILC subsets in common pancreatic diseases, including diabetes mellitus, pancreatitis and pancreatic cancer, and discussed the potential practical implications of the relevant findings for future further treatment of these pancreatic diseases

Stakeholder-oriented multi-objective process optimization based on an improved genetic algorithm

Multi-objective optimization (MOO) is frequently used to solve many practical problems of chemical processes but process designers only need a limited number of valuable solutions in the final results. In this study, an optimization strategy associated with an improved genetic algorithm was developed to search valuable solutions for stakeholders' preference more purposefully. The algorithm was improved to reduce overlapping solutions as a result of the discrete variables in practical problems, and it allowed users to set a reference point or an angle associated with a reference point to make solutions converge into the preferred spaces. Three test functions and two practical problems were used to highlight that the proposed strategy could make designers optimize processes more efficiently. Especially, the angle-based algorithm could be more effective than the distance-based one on the tri-objective problems. Thus, the developed strategy is robust in the optimization of processes assisted with the designer's preference. (C) 2019 Elsevier Ltd. All rights reserved

Efficient Electrochemical Reduction of CO2 to CO in Ionic Liquids

Electrochemical reduction of carbon dioxide (CO2) to CO is a promising strategy. However, achieving high Faradaic efficiency with high current density using ionic liquid (IL) electrolyte remains a challenge. In this study, the new IL N-octyltrimethyl ammonium 1,2,4-triazole ([N-1118][TRIZ]) shows outstanding performance for electrochemical reduction of CO2 to CO on the commercial Ag electrode, and the current density can be up to 50.8 mAcm(-2) with a Faradaic efficiency of 90.6 %. The current density of CO is much higher than those reported in the IL electrolyte. In addition, the density functional theory (DFT) calculation further proved that [N-1118][TRIZ] interact with CO2 to form [N-1118](+)[TRIZ-CO2](-) complex which played a key role in reducing the activation energy of CO2. The formation of [N-1118](+)[TRIZ-CO2](-) complex was verified by Fourier Transform Infrared (FTIR) spectroscopy. According to the molecular orbital theory, the electrons obtained from IL was filled in the anti-bonding orbit (pi*) of the CO2, resulting in reducing the C=O bond energy. This work provides a new strategy to design novel ILs for high efficiency electrochemical reduction of CO2 to CO