Carbonation of Epoxidized Methyl Soyates in Tetrabutylammonium Bromide-Based Deep Eutectic Solvents

Deep Eutectic Solvents or Eutectic Mixtures? Characterization of Tetrabutylammonium Bromide and Nonanoic Acid Mixtures

Deep eutectic solvents have quickly attracted the attention of researchers because they better meet the requirements of green chemistry and thus have the potential to replace conventional hazardous organic solvents in some areas. To better understand the nature of these mixtures, as well as expand the possibilities of their use in different industries, a detailed examination of their physical properties, such as density, viscosity, the nature of the interactions between their constituents, the phase diagrams, depression of their melting point, and interpretation of these results is necessary. In this work, the mixtures of tetrabutylammonium bromide (TBAB) and nonanoic acid (NA) in different molar ratios are theoretically and experimentally investigated by applying a phase diagram constructed on the basis of differential scanning calorimetry measurements and COSMO-RS model. Spectral properties are investigated based on Fourier transform infrared spectroscopy and density functional theory. The observed eutectic point indicates the formation of a DES in the TBAB−NA system in a 1:2 molar ratio. This is due to the presence of hydrogen bonds between the carboxyl group from the NA molecule and the bromine atom from the TBAB molecule. Other eutectic mixtures are most likely the solutions of TBAB in NA, in which hydrogen bonds predominate between acid molecules.

Steroid Sulphatase and Its Inhibitors: Past, Present, and Future

Steroid sulphatase (STS), involved in the hydrolysis of steroid sulphates, plays an important role in the formation of both active oestrogens and androgens. Since these steroids significantly impact the proliferation of both oestrogen- and androgen-dependent cancers, many research groups over the past 30 years have designed and developed STS inhibitors. One of the main contributors to this field has been Prof. Barry Potter, previously at the University of Bath and now at the University of Oxford. Upon Prof. Potter's imminent retirement, this review takes a look back at the work on STS inhibitors and their contribution to our understanding of sulphate biology and as potential therapeutic agents in hormone-dependent disease. A number of potent STS inhibitors have now been developed, one of which, Irosustat (STX64, 667Coumate, BN83495), remains the only one to have completed phase I/II clinical trials against numerous indications (breast, prostate, endometrial). These studies have provided new insights into the origins of androgens and oestrogens in women and men. In addition to the therapeutic role of STS inhibition in breast and prostate cancer, there is now good evidence to suggest they may also provide benefits in patients with colorectal and ovarian cancer, and in treating endometriosis. To explore the potential of STS inhibitors further, a number of second- and third-generation inhibitors have been developed, together with single molecules that possess aromatase-STS inhibitory properties. The further development of potent STS inhibitors will allow their potential therapeutic value to be explored in a variety of hormone-dependent cancers and possibly other non-oncological conditions.

Yield and Selectivity Improvement in the Synthesis of Carbonated Linseed Oil by Catalytic Conversion of Carbon Dioxide

Carbonation of epoxidized linseed oil (CELO) containing five-membered cyclic carbonate (CC5) groups has been optimized to 95% by reacting epoxidized linseed oil (ELO) with carbon dioxide (CO2) and tetrabutylammonium bromide (TBAB) as catalysts. The effect of reaction variables (temperature, CO2 pressure, and catalyst concentration) on the reaction parameters (conversion, carbonation and selectivity) in an autoclave system was investigated. The reactions were monitored, and the products were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance (13C-NMR) and proton nuclear magnetic resonance (1H-NMR) spectroscopies. The results showed that when carrying out the reaction at high temperature (from 90 °C to 120 °C) and CO2 pressure (60-120 psi), the reaction's conversion improves; however, the selectivity of the reaction decreases due to the promotion of side reactions. Regarding the catalyst, increasing the TBAB concentration from 2.0 to 5.0 w/w% favors selectivity. The presence of a secondary mechanism is based on the formation of a carboxylate ion, which was formed due to the interaction of CO2 with the catalyst and was demonstrated through 13C-NMR and FT-IR. The combination of these factors makes it possible to obtain the largest conversion (96%), carbonation (95%), and selectivity (99%) values reported until now, which are obtained at low temperature (90 °C), low pressure (60 psi) and high catalyst concentration (5.0% TBAB).

Extraction of Tocopherol from Soybean Oil Deodorizer Distillate by Deep Eutectic Solvents

Natural tocopherols have strong antioxidant and physiological functions, which are mainly produced from vegetable oil deodorized distillates. In this work, a simple and green solvent extraction method based on deep eutectic solvent has been developed to simultaneously extract three isomers of tocopherols (α, γ and δ-tocopherols) from soybean oil deodorizer distillate (SODD). The key factor to affect the solvent extraction efficiency was proposed that phenolic deep eutectic solvents interacted with targeted tocopherols mainly through π-π bonds interaction. This sustainable extraction process included two steps. Firstly, total tocopherols were extracted from SODD at room temperature by phenolic deep eutectic solvent composed of ChCl and p-cresol. Subsequently, tocopherols were successfully separated from deep eutectic solvent phase by re-extraction with n-hexane, and tocopherols products could be simply recovered. Under the optimum extraction conditions, the extraction efficiency of total tocopherols (α, γ and δ-tocopherols) from SODD was 77.6% after extraction with phenolic deep eutectic solvent.

p-Toluenesulfonic Acid-based Deep Eutectic Solvent as Transesterification Catalyst for Biodiesel Production

In this study, acidic deep eutectic solvents (DESs) have been studied as catalyst in transesterification of soybean oil with methanol to produce biodiesel. p-Toluenesulfonic acid-based deep eutectic solvent (P-DES), composed of p-toluenesulfonic acid and choline chloride (1:3, mol/mol), was found to be an efficient transesterification catalyst for biodiesel production. The optimum conditions for the transesterification process were as follows: 8% P-DES catalyst, 8:1 molar ratio of methanol to oil, reaction temperature of 110°C and 2 h reaction time. The transesterification yield could reach 98.66±0.17%. And the P-DES exhibited as a heterogeneous catalyst after the reaction, which could be separated easily. And P-DES could remove the trace amount of by-product (glycerol) in the final biodiesel product, making this process more simple and cleaner.