Search Results (27)

Polycyclic aromatic compounds can often be made by a sequence featuring an initial Diels–Alder [4 + 2] cycloaddition reaction, followed by cheletropic extrusion of carbon monoxide. These reactions normally require heating the diene and dieneophile in petrochemical-derived aromatic hydrocarbon solvents, such as xylenes or diphenyl ether. This article summarizes the results of attempts to use renewable solvents in place of those currently in use to prepare pentaphenylbenzene and 1,2,4-triphenyltriphenylene. Dihydrolevoglucosenone, p-cymene, ethyl lactate, diethyl carbonate, and cyclopentyl methyl ether have all been successfully evaluated as renewable solvent alternatives in Diels–Alder/cheletropic reaction sequences. An analysis of the products from the reactions investigated did not show evidence of oxidative degradation of the diene reactants. Furthermore, norbornadien-7-one intermediates were not isolated from any of the reactions tested. Full article

The transition toward sustainable conservation practices requires a scientifically ground approach to substituting traditional solvent systems with green alternatives. This study aims to facilitate the adoption of green solvents by restoration professionals by systematically evaluating their chemical compatibility and toxicological safety. By integrating Hansen solubility parameters (HSP), Relative Energy Difference (RED), and the Integrated Toxicity Index (ITI), we identified green solvents with high potential for replacing Cremonesi mixtures. The analysis revealed that ether-based solvents, such as 2,5-dimethyltetrahydrofuran and cyclopentyl methyl ether, exhibit high chemical affinity with Cremonesi mixtures, while esters and fatty acid methyl esters (FAMEs) offer a balanced combination of solubility and low toxicity. However, the study also underscores significant gaps in safety data (SDS) for many innovative solvents, highlighting the need for further toxicological evaluation before widespread implementation. Full article

This study outlines the sustainable synthesis of novel hydroxytyrosol (HT) and tyrosol (T) ester derivatives via a Pd-catalyzed alkoxycarbonylation of aromatic iodides. The high sustainability of the process is attributed to the use of (1) a solid carbon monoxide source, Mo(CO)₆, in place of dangerous gaseous CO; (2) a biomass-derived organic solvent, CPME (cyclopentyl methyl ether); (3) naturally occurring hydroxylated compounds, such as HT and T, which could be derived from agricultural waste rather than produced from petroleum-based sources. The method enables the regioselective preparation of various HT and T esters in a short reaction time (4–8 h), under mild temperatures (80 °C), and with moderate-to-excellent yields (62–93%). Moreover, in vitro biological tests have demonstrated that, in addition to the well-known antioxidant properties typical of natural phenolic compounds such as HT and T, some of the newly synthesized derivatives have a safe profile and are effective inhibitors of the α-glucosidase with potential application in the management of hyperglycemia. This synthetic approach offers a promising strategy for exploring biologically relevant chemical space, bridging the gap between natural products and sustainable drug synthesis. Full article

Background/Objectives: The genus Ferula has been traditionally used for the treatment of various illnesses, but the potential of Ferula persica var. latisecta against different Alzheimer’s disease (AD) hallmarks has never been achieved. Methods: In this work, a pressurized liquid extraction (PLE) method was optimized to extract F. persica L. aerial parts and roots. Four different solvents (water, ethanol, ethyl acetate (EtAc), and cyclopentyl methyl ether (CPME)) were first tested, and the extraction yield, total phenolic content, reactive oxygen species scavenging capacity, and acetylcholinesterase (AChE) inhibition activity were evaluated. Results: The results indicated that EtAc and CPME were the best solvents to be used, with the results obtained from the aerial parts being better than those obtained from the root samples. Thereafter, the PLE method was further optimized by combining these solvents in different percentages (100% EtAc, 100% CPME, and 50:50% (v/v) EtAc:CPME) and temperatures (50, 115, and 180 °C). Response surface methodology was then applied to analyze the data, and two optimum extraction conditions were obtained: EtAc:CPME (79:21%) at 180 °C for the aerial parts and 100% CPME at 180 °C for the roots. At these conditions, the total flavonoid content (TFC) and the inhibitory capacities against butyrylcholinesterase (BChE) and lipoxygenase (LOX) enzymes were also evaluated, indicating that the aerial part extracts had higher TFC and LOX inhibitory capacity than the root extracts but lower activity against BChE. The comprehensive LC/GC-MS chemical characterization allowed for the tentative identification of 222 compounds belonging to 66 chemical subclasses, the abundancies of which widely varied depending on the matrix and the extraction conditions used. Conclusions: The results obtained together with the application of advanced statistical analysis and molecular docking simulations suggested several sesquiterpenoids, such as selina-3,7(11)-diene, guaiol acetate, α-cyperone, and farnesyl acetate, as the molecules responsible of the in vitro results observed, with good neuroprotective potential against AD. Full article

This study investigates the performance of cyclopentyl methyl ether (CPME) in the extraction of fenugreek seed oil, aiming to replace the conventionally used hexane. The efficiency of this alternative solvent was evaluated first through in silico methods (based on Hansen Solubility Parameters (HSPs) and Conductor-like Screening Model for Real Solvent (COSMO-RS) simulations), followed by experimental studies. Solubility computational predictions analysis revealed that CPME exhibits superior solvation power compared to hexane. Experimentally, CPME demonstrated a significantly higher oil yield (7.23%) compared to hexane (4.25%) and a better retention of beneficial unsaturated fatty acids than hexane. Additionally, the physicochemical properties of oils extracted with CPME showed enhanced oxidative stability, sterol, tocopherol, and phenolic contents, leading to superior antioxidant and antibacterial activities. Importantly, CPME’s low volatile organic compound (VOC) emissions further establish it as a more sustainable and environmentally friendly alternative to hexane, aligning with contemporary goals of reducing harmful emissions in extraction processes. Thus, this paper highlights the functional advantages of CPME, focusing on its efficiency, selectivity, and enhanced retention of bioactive compounds, positioning it as a superior extraction solvent for fenugreek seed oil compared to hexane. Full article

In this research, the biochar-based tin-loaded heterogeneous catalyst Sn-NUS-BH was used for the efficient catalytic conversion of corncob (CC) in a green biphasic system of cyclopentyl methyl ether–water (CPME-H₂O). By optimizing the system conditions (CPME to H₂O ratio, Sn-NUS-BH dosage, reaction time, and reaction temperature), the stubborn structure of corncobs was maximally disrupted. The chemical composition and structural characteristics (accessibility, lignin surface area, and hydrophobicity) of CC before and after treatment were assessed, demonstrating that the natural physical barriers of CC were disrupted and lignin was effectually eliminated. The accessibility was enhanced from 137.5 mg/g to 518.5 mg/g, the lignin surface area declined from 588.0 m²/g to 325.0 m²/g, and the hydrophobicity was changed from 4.7 L/g to 1.3 L/g. Through the treatment at 170 °C for 20 min, furfural (11.7 g/L) and xylooligosaccharides (4.5 g/L) were acquired in pretreatment liquor. The residual CC could be enzymatically saccharified into reducing sugars in a yield of 65.2%. The combination pretreatment with the tin-based biochar chemocatalyst Sn-NUS-BH combined with the green solvent system CPME-H₂O shows great promise in the valorization of biomass. Full article

Furfural, an important biobased compound, can be synthesized through the chemocatalytic conversion of D-xylose and hemicelluloses from lignocellulose. It has widespread applications in the production of valuable furans, additives, resins, rubbers, synthetic fibers, polymers, plastics, biofuels, and pharmaceuticals. By using barley hulls (BHs) as biobased support, a heterogeneous biochar Sn-NUS-BH catalyst was created to transform corncob into furfural in cyclopentyl methyl ether–H₂O. Sn-NUS-BH had a fibrous structure with voids, a large comparative area, and a large pore volume, which resulted in more catalytic active sites. Through the characterization of the physical and chemical properties of Sn-NUS-BH, it was observed that the Sn-NUS-BH had tin dioxide (Lewis acid sites) and a sulfonic acid group (Brønsted acid sites). This chemocatalyst had good thermostability. At 170 °C for 20 min, Sn-NUS-BH (3.6 wt%) was applied to transform 75 g/L of corncob with ZnCl₂ (50 mM) to generate furfural (80.5% yield) in cyclopentyl methyl ether–H₂O (2:1, v/v). This sustainable catalytic process shows great promise in the transformation of lignocellulose to furfural using biochar-based chemical catalysts. Full article

In a previous study, we demonstrated a change in membrane morphology and gas separation performance by varying the recipe of a casting solution based on polysulfone in a certain solvent system. Although all results were reproducible, all used solvents were harmful and not sustainable. In this study, the solvents tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc) are replaced by the more sustainable solvents 2-methyl-tetrahydrofuran (2M-THF), N-butyl pyrrolidinone (NBP) and cyclopentyl methyl ether (CPME). The gas permeation performance and, for the first time, morphology of the membranes before and after solvent replacement were determined and compared by single gas permeation measurements and SEM microscopy. It is shown that THF can be replaced by 2M-THF and NBP without decreasing the gas permeation performance. With CPME replacing THF, no membranes were formed. Systems with 2M-THF as a THF alternative showed the best gas permeation results. Permeances for the tested gases oxygen (O₂), nitrogen (N₂), carbon dioxide (CO₂) and methane (CH₄) were 5.91 × 10⁻², 8.84 × 10⁻³, 4.00 × 10⁻¹ and 1.00 × 10⁻² GPU, respectively. Permselectivities of those membranes for the gas pairs O₂/N₂, CO₂/N₂ and CO₂/CH₄ were 6.7, 38.3 and 34.0, respectively. When also replacing DMAc in the solvent system, no or only porous membranes were obtained, even if the precipitation procedure was adjusted. These findings indicate that a complete replacement of the solvent system without affecting the membrane morphology or gas permeation performance is not possible. By varying the temperature of the precipitation bath, the formation of mechanically stable PSU membranes is possible only if THF is replaced by 2M-THF. Full article

Three-way catalysts (TWCs) are widely used in vehicles to convert the exhaust emissions from internal combustion engines into less toxic pollutants. After around 8–10 years of use, the declining catalytic activity of TWCs causes them to need replacing, leading to the generation of substantial amounts of spent TWC material containing precious metals, including palladium. It has previously been reported that [NⁿBu₄]₂[Pd₂I₆] is obtained in high yield and purity from model TWC material using a simple, inexpensive and mild reaction based on tetrabutylammonium iodide in the presence of iodine. In this contribution, it is shown that, through a simple ligand exchange reaction, this dimeric recovery complex can be converted into PdI₂(dppf) (dppf = 1,1′-bis(diphenylphosphino)ferrocene), which is a direct analogue of a commonly used catalyst, PdCl₂(dppf). [NⁿBu₄]₂[Pd₂I₆] displayed high catalytic activity in the oxidative functionalisation of benzo[h]quinoline to 10-alkoxybenzo[h]quinoline and 8-methylquinoline to 8-(methoxymethyl)quinoline in the presence of an oxidant, PhI(OAc)₂. Near-quantitative conversions to the desired product were obtained using a catalyst recovered from waste under milder conditions (50 °C, 1–2 mol% Pd loading) and shorter reaction times (2 h) than those typically used in the literature. The [NⁿBu₄]₂[Pd₂I₆] catalyst could also be recovered and re-used multiple times after the reaction, providing additional sustainability benefits. Both [NⁿBu₄]₂[Pd₂I₆] and PdI₂(dppf) were also found to be active in Buchwald–Hartwig amination reactions, and their performance was optimised through a Design of Experiments (DoE) study. The optimised conditions for this waste-derived palladium catalyst (1–2 mol% Pd loading, 3–6 mol% of dppf) in a bioderived solvent, cyclopentyl methyl ether (CPME), offer a more sustainable approach to C-N bond formation than comparable amination protocols. Full article

Aryl and heteroaryl iodides have been efficiently converted into the corresponding thioacetates in cyclopentyl methyl ether (CPME), a green solvent, under Cu catalysis. The chemoselectivity of the reaction is mainly controlled by electronic factors, enabling the conversion of both electron-rich and electron-deficient substrates into the corresponding thioacetates in good to excellent yields. The products can be easily deprotected to the corresponding thiolates to carry out additional synthetic transformations in situ. Surprisingly, despite CPME’s relatively low dielectric constant, the reaction rate significantly increased when conducted under microwave irradiation conditions. This synthetic methodology exhibits a remarkable tolerance to functional groups, mild reaction conditions, and a wide substrate scope, utilizing a safe and inexpensive CuI pre-catalyst in the green solvent CPME. A non-aqueous workup allowing for the complete recovery of both catalyst and solvent makes this approach an environmentally sustainable protocol for C(sp²) sulfur functionalization. Additionally, the reaction shows selective cross-coupling with iodides in competition with chlorides and bromides, allowing its use in multistep syntheses. To demonstrate the potential of this methodology, it was applied to the high-yield synthesis of a photochromic dithienylethene, where a selective synthesis had not been reported before. Full article

An overview of solvent replacement strategies shows that there is great progress in green chemistry for replacing hazardous di-polar aprotic solvents, such as N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone (NMP), and 1,4-dioxane (DI), used in processing active industrial ingredients (APIs). In synthetic chemistry, alcohols, carbonates, ethers, eucalyptol, glycols, furans, ketones, cycloalkanones, lactones, pyrrolidinone or solvent mixtures, 2-methyl tetrahydrofuran in methanol, HCl in cyclopentyl methyl ether, or trifluoroacetic acid in propylene carbonate or surfactant water (no organic solvents) are suggested replacement solvents. For the replacement of dichloromethane (DCM) used in chromatography, ethyl acetate ethanol or 2-propanol in heptanes, with or without acetic acid or ammonium hydroxide additives, are suggested, along with methanol acetic acid in ethyl acetate or methyl tert-butyl ether, ethyl acetate in ethanol in cyclohexane, CO₂-ethyl acetate, CO₂-methanol, CO₂-acetone, and CO₂-isopropanol. Supercritical CO₂ (scCO₂) can be used to replace many organic solvents used in processing materials from natural sources. Vegetable, drupe, legume, and seed oils used as co-extractants (mixed with substrate before extraction) can be used to replace the typical organic co-solvents (ethanol, acetone) used in scCO₂ extraction. Mixed solvents consisting of a hydrogen bond donor (HBD) solvent and a hydrogen bond acceptor (HBA) are not addressed in GSK or CHEM21 solvent replacement guides. Published data for 100 water-soluble and water-insoluble APIs in mono-solvents show polarity ranges appropriate for the processing of APIs with mixed solvents. When water is used, possible HBA candidate solvents are acetone, acetic acid, acetonitrile, ethanol, methanol, 2-methyl tetrahydrofuran, 2,2,5,5-tetramethyloxolane, dimethylisosorbide, Cyrene, Cygnet 0.0, or diformylxylose. When alcohol is used, possible HBA candidates are cyclopentanone, esters, lactone, eucalytol, MeSesamol, or diformylxylose. HBA—HBA mixed solvents, such as Cyrene—Cygnet 0.0, could provide interesting new combinations. Solubility parameters, Reichardt polarity, Kamlet—Taft parameters, and linear solvation energy relationships provide practical ways for identifying mixed solvents applicable to API systems. Full article

Tetraselmis chuii is an EFSA-approved novel food and dietary supplement with increasing use in nutraceutical production worldwide. This study investigated the neuroprotective potential of bioactive compounds extracted from T. chuii using green biobased solvents (ethyl acetate, AcOEt, and cyclopentyl methyl ether, CPME) under pressurized liquid extraction (PLE) conditions and supercritical fluid extraction (SFE). Response surface optimization was used to study the effect of temperature and solvent composition on the neuroprotective properties of the PLE extracts, including anticholinergic activity, reactive oxygen/nitrogen species (ROS/RNS) scavenging capacity, and anti-inflammatory activity. Optimized extraction conditions of 40 °C and 34.9% AcOEt in CPME resulted in extracts with high anticholinergic and ROS/RNS scavenging capacity, while operation at 180 °C and 54.1% AcOEt in CPME yielded extracts with potent anti-inflammatory properties using only 20 min. Chemical characterization revealed the presence of carotenoids (neoxanthin, violaxanthin, zeaxanthin, α- and β-carotene) known for their anti-cholinesterase, antioxidant, and anti-inflammatory potential. The extracts also exhibited high levels of omega-3 polyunsaturated fatty acids (PUFAs) with a favorable ω-3/ω-6 ratio (>7), contributing to their neuroprotective and anti-inflammatory effects. Furthermore, the extracts were found to be safe to use, as cytotoxicity assays showed no observed toxicity in HK-2 and THP-1 cell lines at or below a concentration of 40 μg mL⁻¹. These results highlight the neuroprotective potential of Tetraselmis chuii extracts, making them valuable in the field of nutraceutical production and emphasize the interest of studying new green solvents as alternatives to conventional toxic solvents. Full article

Asymmetric ethers such as Cyclopentyl Methyl Ether (CPME) found their application as alternative solvents in technology; they are often labeled as “green solvents” as they can be prepared using renewable feedstock. They are almost immiscible with water and can be easily regenerated. Based on earlier experiments with CPME preparation in laboratory conditions and the estimated product yields, an initial assessment of the reaction mixture separation train was performed, for the chosen production capacity of 100 kg·h⁻¹ of CPME. Following suitable thermodynamic model selection, basic analyses in Aspen Plus software were executed. Reactor effluent containing eight chemical species was subjected to multiple separation steps including extraction and several rectifications including one vapor phase compression step to yield saleable products with sufficient purity and unreacted chemicals recyclable to the reactor. Basic simulations were performed to find the optimal working conditions of individual columns and to estimate the associated energy needs. Basic design, without any heat or work integration measures, required a total heating duty of 787 kW and a total cooling duty of 614 kW. This yielded a specific heat consumption of 28.3 GJ per ton of the main product (CPME) which is unacceptably high as it represents around 70% of its chemical energy content (heating value). Further research will be devoted to reducing heating and cooling duty by integrated separation train design development to comply with the reduced carbon footprint mandatory for the syntheses and separations of green solvents. Full article

The present study aimed to investigate the qualitative and quantitative performance of five green solvents, namely 2-methyltetrahydrofuran (MeTHF), cyclopentyl methyl ether (CPME), p-cymene, d-limonene and ethanol to substitute n-hexane, for sesame seed oil extraction. In fact, both CPME and MeTHF gave higher crude yields than n-hexane (58.82, 54.91 and 50.84%, respectively). The fatty acid profile of the sesame seed oils remained constant across all the solvent systems, with a predominance of oleic acid (39.27–44.35%) and linoleic acid (38.88–43.99%). The total sterols gained the upmost amount with CPME (785 mg/100 g oil) and MeTHF (641 mg/100 g oil). CPME and MeTHF were also characterized by the optimum content of tocopherols (52.3 and 50.6 mg/100 g oil, respectively). The highest contents of total phenols in the sesame seed oils were extracted by CPME (23.51 mg GAE/g) and MeTHF (22.53 mg GAE/g) as compared to the other solvents, especially n-hexane (8 mg GAE/g). Additionally, sesame seed oils extracted by MeTHF and CPME also had the highest antioxidant and anti-inflammatory properties as compared to the other green solvents and n-hexane, encouraging their manufacturing use for sesame seed oil extraction. Full article

A sustainable enzymatic strategy for the preparation of amides by using Candida antarctica lipase B as the biocatalyst and cyclopentyl methyl ether as a green and safe solvent was devised. The method is simple and efficient and it produces amides with excellent conversions and yields without the need for intensive purification steps. The scope of the reaction was extended to the preparation of 28 diverse amides using four different free carboxylic acids and seven primary and secondary amines, including cyclic amines. This enzymatic methodology has the potential to become a green and industrially reliable process for direct amide synthesis. Full article