Calculation of a permitted daily exposure value for the solvent 2-methyltetrahydrofuran

Catalytic Conversion of Levulinic Acid into 2-Methyltetrahydrofuran: A Review

Biomass-derived furanics play a pivotal role in chemical industries, with 2-methyltetrahydrofuran (2-MTHF), a hydrogenated product of levulinic acid (LA), being particularly significant. 2-MTHF finds valuable applications in the fuel, polymer, and chemical sectors, serving as a key component in P-series biofuel and acknowledged as a renewable solvent for various chemical processes. Numerous research groups have explored catalytic systems to efficiently and selectively convert LA to 2-MTHF, using diverse metal-supported catalysts in different solvents under batch or continuous process conditions. This comprehensive review delves into the impact of metal-supported catalysts, encompassing co-metals and co-catalysts, on the synthesis of 2-MTHF from LA. The article also elucidates the influence of different reaction parameters, such as temperature, type and quantity of hydrogen source, and time. Furthermore, the review provides insights into reaction mechanisms for all documented catalytic systems.

Dissolution Improvement of Progesterone and Testosterone via Impregnation on Mesoporous Silica Using Supercritical Carbon Dioxide

Progesterone (PRG) and testosterone (TST) were impregnated on mesoporous silica (ExP) particles via supercritical carbon dioxide (scCO2) processing at various pressures (10–18 MPa), temperatures (308.2–328.2 K), and time (30–360 min). The impact of a co-solvent on the impregnation was also studied at the best determined pressure and temperature. The properties of the drug embedded in silica particles were analysed via gas chromatography (GC), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and nitrogen adsorption. An impregnation of 1 to 82 mg/g for PRG and 0.1 to 16 mg/g for TST was obtained depending on the processing parameters. There was a significant effect of pressure, time, and co-solvent on the impregnation efficiency. Generally, an increase in time and pressure plus the use of co-solvent led to an improvement in drug adsorption. Conversely, a rise in temperature resulted in lower impregnation of both TST and PRG on ExP. There was a substantial increase in the dissolution rate (> 90% drug release within the first 2 min) of both TST and PRG impregnated in silica particles when compared to the unprocessed drugs. This dissolution enhancement was attributed to the amorphisation of both drugs due to their adsorption on mesoporous silica.

Graphical Abstract

Application of Biobased Solvents in Asymmetric Catalysis

The necessity of more sustainable conditions that follow the twelve principles of Green Chemistry have pushed researchers to the development of novel reagents, catalysts and solvents for greener asymmetric methodologies. Solvents are in general a fundamental part for developing organic processes, as well as for the separation and purification of the reaction products. By this reason, in the last years, the application of the so-called green solvents has emerged as a useful alternative to the classical organic solvents. These solvents must present some properties, such as a low vapor pressure and toxicity, high boiling point and biodegradability, and must be obtained from renewable sources. In the present revision, the recent application of these biobased solvents in the synthesis of optically active compounds employing different catalytic methodologies, including biocatalysis, organocatalysis and metal catalysis, will be analyzed to provide a novel tool for carrying out more ecofriendly organic processes.

Higher Yield and Polyphenol Content in Olive Pomace Extracts Using 2-Methyloxolane as Bio-Based Solvent

Despite its severe toxicity and negative environmental impact, hexane remain the solvent of choice for the extraction of vegetable oils. This is in contrast with the constantly growing demand for sustainable and green extraction processes. In recent years a variety of alternatives to hexane have been reported, among them 2-methyloxolane (2-MeOx), which has emerged as a promising bio-based alternative. This study evaluates the possibility of replacing hexane, in the extraction of olive pomace (OP), with 2-MeOx, both dry and saturated with water (4.5%), the latter of which is called 2-MeOx 95.5%. The three solvents have been compared in terms of extraction yield and quality, as well as the lipid and polyphenol profiles of the extracts. The work concluded that both dry 2-MeOx and 2-MeOx 95.5% can replace hexane in OP extraction, resulting in higher yields and extracts richer in phenolic compounds. This study should open the road to further semi-industrial scale investigations toward more sustainable production processes.

Safety assessment of 2‐methyloxolane as a food extraction solvent

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of 2‐methyloxolane as an extraction solvent under the intended conditions of use and the maximum residue limits (MRLs) proposed by the applicant. 2‐Methyloxolane is intended to be used in processes currently applying hexane for oil and protein extraction from plant sources or for extraction of food additives. The proposed MRLs for the following uses are: (i) 1 mg/kg in fat, oil or butter; (ii) 10 mg/kg in defatted protein products, defatted flour and other defatted solid ingredients; (iii) 1 mg/kg in food category 13 (foods intended for particular nutritional uses as defined by Directive 2009/39/EC); and (iv) 1 mg/kg for the extraction of food additives. The Panel calculated the dietary exposure with the highest potential maximum (95th percentile) for toddlers as 0.32 mg/kg body weight (bw) per day. Based on the available toxicological data, the Panel concluded that 2‐methyloxolane was rapidly metabolised with a low bioaccumulation potential and does not raise a concern for genotoxicity. The Panel identified different no observed adverse effect levels (NOAELs) in a subchronic oral toxicity study in rats, an oral developmental toxicity study and an extended one‐generation reproductive toxicity study, and a TDI of 1 mg/kg bw per day for 2‐methyloxolane was derived based on the lowest identified NOAEL (100 mg/kg bw per day) for reproductive and developmental toxicity. This TDI was not exceeded in any of the population groups at the mean and 95th percentile exposure. The Panel concluded that the extraction solvent 2‐methyloxolane does not raise a safety concern when used according to the intended conditions and at the proposed MRLs in the extracted foods or food ingredients.

Determination of Antioxidant 264 in the Butyl Rubber Stopper and the Compatibility with Recombinant Potent Antitumor and Antivirus Protein Injection

OBJECTIVE

To establish a method for extraction and determination of antioxidant 264 (2,6-di-tert-butyl-4-methylphenol) in the brominated butyl rubber stopper for injection and migration study in recombinant potent antitumor and antivirus protein injection (Novaferon).

METHODS

Dichloromethane-ethanol was adopted as the extraction solvent during the process of reflux extraction of antioxidant 264 in the brominated butyl rubber stopper. High-performance liquid chromatography (HPLC) was used for the determination of the migration of antioxidant 264 to Novaferon. The mobile phase consisted of acetonitrile-water (80 : 20, v/v). The flow rate was 1.5 mL/min. The detection wavelength was 280 nm.

RESULTS

The linearity range was from 4.003 to 200.150 μg/mL (r ² = 0.99996), and the average recovery of antioxidant 264 was 97.8%. The applicability of the methodology was good, which can be used for the determination of antioxidant 264. The results indicated that antioxidant 264 was not detected in Novaferon after the accelerated test and three months of long-term test.

CONCLUSION

The established validated method in this study can be used for the determination of antioxidant 264 in the rubber stopper, and the brominated butyl rubber stopper has good compatibility with Novaferon.

2-Methyloxolane (2-MeOx) as Sustainable Lipophilic Solvent to Substitute Hexane for Green Extraction of Natural Products. Properties, Applications, and Perspectives

This review presents a complete picture of current knowledge on 2-methyloxolane (2-MeOx), a bio-based solvent for the extraction of natural products and food ingredients. It provides the necessary background about the properties of 2-MeOx, not only its solvent power and extraction efficiency, but its detailed toxicological profile and environmental impacts are discussed. We compared 2-MeOx with hexane which is the most used petroleum-based solvent for extraction of lipophilic natural products. The final part focuses on successful industrial transfer, including technologic, economic, and safety impacts. The replacement of petroleum-based solvents is a hot research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that 2-MeOx is an environmentally and economically viable alternative to conventional petroleum-based solvents for extraction of lipophilic foodstuff and natural products.

Whole-Cell Catalytic Synthesis of Puerarin Monoesters and Analysis of Their Antioxidant Activities

Puerarin, an important isoflavonoid from the edible root of Pueraria lobata, shows multiple bioactivities but suffers from low bioavailability. In this study, a new whole-cell catalytic method for acylation modification of puerarin was developed. Among the 12 strains tested, Aspergillus oryzae showed the highest catalytic activity and selectively catalyzed acylation of puerarin at the 6″-hydroxyl group. The organic solvents used significantly influenced the catalytic efficiency of the cells. In the green solvent 2-methyltetrahydrofuran, the reaction showed high substrate conversion (92.5%) and regioselectivity (95.8%), with results similar to those with tetrahydrofuran (94.2% and 98.5%, respectively) under optimal conditions. The monoester products showed higher liposolubility in comparison to puerarin, and those with C3-C8 fatty acid chain lengths showed evidently improved antioxidant activity toward erythrocyte hemolysis. Considering the operational stability of the cells and efficiency of the scaled-up reactions, this method is efficient and cost effective, with promising applications in the health food industry.

Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

The application of heterogeneous catalysis and green solvents to the set up of widely employed reactions is a challenge in contemporary organic chemistry. We applied such an approach to the synthesis and further conversion of tetrahydropyranyl ethers, an important class of compounds widely employed in multistep syntheses. Several alcohols and phenols were almost quantitatively converted into the corresponding tetrahydropyranyl ethers in cyclopentyl methyl ether or 2-methyltetrahydrofuran employing NH₄HSO₄ supported on SiO₂ as a recyclable acidic catalyst. Easy work up of the reaction mixtures and the versatility of the solvents allowed further conversion of the reaction products under one-pot reaction conditions.