Solvent Recycling Research Articles

High-yield gram-scale organic synthesis using accelerated microdroplet/thin film reactions with solvent recycling.

A closed system has been designed to perform microdroplet/thin film reactions with solvent recycling capabilities for gram-scale chemical synthesis. Claisen–Schmidt, Schiff base, Katritzky and Suzuki coupling reactions show acceleration factors relative to bulk of 15 to 7700 times in this droplet spray system. These values are much larger than those reported previously for the same reactions in microdroplet/thin film reaction systems. The solvent recycling mode of the new system significantly improves the reaction yield, especially for reactions with smaller reaction acceleration factors. The microdroplet/thin film reaction yield improved on recycling from 33% to 86% and from 32% to 72% for the Katritzky and Suzuki coupling reactions, respectively. The Claisen–Schmidt reaction was chosen to test the capability of this system in gram scale syntheses and rates of 3.18 g per h and an isolated yield of 87% were achieved.

Conversion of birch bark to biofuels

Birch bark was converted to a hydrocarbon biofuel through solubilization and hydrotreatment. The procedure implements a recyclable, salt- and metal-free solvent system and has been evaluated by Life-Cycle Assessment.

Minimizing solvent waste in catalytic reactions in highly recyclable hydrocarbon solvents.

This paper describes chemistry using organocatalysts in hydrocarbon solvents that minimizes solvent waste by using inexpensive, non-volatile, relatively inflammable, and easily recyclable poly(α-olefin)s (PAOs) as hydrocarbon solvents. These studies show that when substrates have limited solubility in PAO solvents, this issue can be addressed by adding a small amount of a cosolvent. Kinetic studies were also carried out and show that reactions carried out in PAOs are kinetically comparable to reactions in conventional non-recyclable hydrocarbon solvents. A range of strategies that separate and isolate products from reactions in PAOs using a polyisobutylene (PIB)-supported DMAP catalyst have been studied using four different catalytic reactions. In the most general procedure, the PAO phase containing a PIB-bound catalyst is separated from products by low energy liquid/liquid gravity separation. This can be accomplished using a minimal amount of a polar solvent. In another example, the product's low solubility leads to it precipitating during the reaction. In this case, a simple filtration recycles the PAO and a PIB-bound DMAP catalyst. We have demonstrated that the PAO phase containing a PIB bound DMAP catalyst can be recycled for at least 10 cycles without loss of activity. Our studies further showed that leaching of the PAO phase into polar solvents was orders of magnitude less than conventional hydrocarbon solvents such as heptane. The result is that the overall solvent waste generation is lower than for the same reaction carried out in conventional solvents.

Microwave assisted synthesis of some Traditional reactions: Green chemistry approach

The microwave assisted organic reaction comes under green chemistry proved to be eco-friendly and higher yield. In present article we performed some organic reactions using microwave irradiation. This green processes have resulted through use of less or no catalyst, readily recyclable solvents and yield that are often higher than conventional method. Microwave heating produces heat in entire material in the same rate and the same time at a high speed and at a high rate of reaction. Microwave assisted synthesis has become an important tool to the medicinal chemist for rapid organic synthesis. The microwave reactions were performed using microwave assisted synthesis on microwave, the reactions were worked up extensively to obtain a pure form of product which was isolated using literature work-up procedures. The products were further recrystallized with suitable solvents. The reactions were monitored with TLC intermittently for microwave assisted synthesis and hourly for conventional method of synthesis.

A new approach to large scale production of dimethyl sulfone: a promising and strong recyclable solvent for ligand-free Cu-catalyzed C–C cross-coupling reactions

Dimethyl sulfone (DMSN or MSM) was preparedviaefficient oxidation of dimethyl sulfoxide and used and developed as an efficient, viscose, and recyclable solvent for ligand-free CuI-catalyzed Heck, Suzuki, and Sonogashira cross-coupling reactions.

The Current State of the Organic Solvent Recycle and Expectation of Membrane Separation Applicable to this Recycle

The Current State of the Organic Solvent Recycle and Expectation of Membrane Separation Applicable to this Recycle

Conversion of D-fructose to 5-acetoxymethyl-2-furfural Using Immobilized Lipase and Cation Exchange Resin.

5-Acetoxymethyl-2-furfural (AMF) was prepared from D-fructose via 1,6-diacetylfructose (DAF) through a simple two-step reaction pathway. Immobilized enzyme (Novozym 435) was found to be the best enzymatic catalyst for the trans-esterification step (yielding 94.6% DAF). In the dehydration step, while soluble H2SO4 was found to be the best acidic catalyst (yielding 86.6% AMF), we opted to utilize heterogeneous cation exchange resin (Amberlyst 15) together with recyclable industrial solvents (1,4-dioxane) for a more sustainable AMF synthesis procedure. Although the total yield of AMF was a little lower, both the enzyme and the solid acid catalyst could be recycled for five cycles without a significant loss of activity, which has a major contribution to the cost-efficient aspect of the entire process.

Polyoxometalate‐supported Pd nanoparticles as efficient catalysts for the Mizoroki‐Heck cross‐coupling reactions in PEG medium

Palladium nanoparticles supported on polyoxometalate as a solid carrier were successfully prepared and evaluated as a heterogeneous nanocatalyst for the Mizoroki‐Heck cross‐coupling reactions. This supported catalyst was characterized by a set of techniques, including XRD, chemical analysis (ICP‐OES), IR spectroscopy, TEM and FE‐SEM analyses. Poly (ethylene glycol) was employed as an environmentally friendly solvent for coupling reactions. The various fundamental reaction parameters that influence the efficiency of the reaction and yield of the desired reaction products were optimized. This catalytic system showed good activities and evolve a strategy for achieving five times catalyst and green solvent recyclability without appreciable loss of its activity, thus making this protocol eco‐friendly.

Solubility of Caffeine in Supercritical CO2: A Molecular Dynamics Simulation Study.

The extraction of caffeine from green tea leaves and cocoa beans is a common industrial process for the production of decaffeinated beverages and pharmaceuticals. The choice of the solvent critically determines the yield of this extraction process. Being an environmentally benign and recyclable solvent, supercritical carbon dioxide (scCO2) has emerged as the most desirable green solvent for caffeine extraction. The present study investigates the solvation properties of caffeine in scCO2 at two different temperatures (318 and 350 K) using molecular dynamics simulations. Unlike in water, the caffeine molecules in scCO2 do not aggregate to form clusters due to relatively stronger caffeine-CO2 interactions. A well-structured scCO2 solvent shell envelops each caffeine molecule as a result of strong electron-donor-acceptor (EDA) and hydrogen-bonding interactions between these two species. Upon heating, although marginal site-specific changes in the distribution of nearest CO2 around caffeine are observed, the overall distribution is retained. At a higher temperature, the caffeine-CO2 hydrogen-bonding interactions are weakened, while their EDA interactions become relatively stronger. The results underscore the importance of the interplay of these interactions in determining stable solvent structures and solubility of caffeine in scCO2.

Recyclable menthol-based deep eutectic solvent micellar system for extracting phytochemicals from Ginkgo biloba leaves

Abstract With an emphasis on human health, the demand for natural products is progressively increasing and sustainable extraction technologies for phytochemicals are receiving greater attention. In the present study, we established a naturally recyclable two-phase aqueous micellar system comprising menthol-based hydrophobic deep eutectic solvent (DES) in water. Typical representative phytochemicals from Ginkgo biloba leaves included flavonoid glycosides, terpene lactones, and bioflavonoids. These compounds have differing polarities and were selected as targets for the evaluation of our novel menthol-based aqueous DES as a green and sustainable extraction technology for partitioning various compounds. Components of the aqueous DES system and extraction process were systematically studied, and the following optimal conditions were identified: menthol–acetic acid ratio of 1:1 (mol/mol), DES–water ratio of 1:1 (v/v), solid–liquid ratio of 15:1 (mg/mL), extraction power of 200 W, and extraction time of 10 min. The two-phase system easily separated compounds with differing polarity into the upper (DES-rich phase) and lower (water phase) phases after extraction. Analyses of the related mechanisms indicated that micelle formation of menthol-based DES in water was the dominant separating process and that this process provided large contact areas between target compounds and extraction solvent, thereby promoting extraction from G. biloba leaves. Moreover, this aqueous DES system could efficiently be recovered and reused in regeneration studies. This novel menthol-based aqueous DES system provides a sustainable extraction technology for various phytochemicals from plant materials.

Techno-economic assessment of conventional and direct-transesterification processes for microalgal biomass to biodiesel conversion

The simplified direct-transesterification (DT) process was compared to the conventional biodiesel production process based on a reported previous experimental work with economic standpoint. Based on the process flow diagram, capital and operating costs were itemized properly and then unit biodiesel production cost was calculated. The results show the biodiesel production costs were 18.2 $ kg−1 (conventional process) and 12.5 $ kg−1 (DT process), respectively. Sensitivity analysis shows the source of biomass and chemical consumption are the major factors to determine total biodiesel production cost. The affecting factors were a solvent recycling, yield of biodiesel, and plant capacity and these values were varied to evaluate the variation of unit biodiesel production cost. As a result, the maximized biodiesel production cost went down to 3.5 $ kg−1, which is cost-competitive with other reported values of production cost.

Investigation of OSN properties of PDMS membrane for the retention of dilute solutes with potential industrial applications

ABSTRACTFew commercially available membranes can be used for organic solvent nanofiltration (OSN). Applying OSN in chemical industries is nevertheless of high interest to cut with energy consumption linked to solvent recycling and soluble catalysts recovery. A commercial membrane, PERVAP4060, was used to investigate the retention of dilute solutes in toluene feeds and to mimic metathesis medium. The studied solutes were R‐BINAP a neutral polyaromatic molecule used in metathesis chemistry, tetraoctylammonium bromide (ToABr), a charged molecule used as a homogeneous catalyst and n‐hexadecane. Retention of polar ToABr (95%) was higher than that of neutral R‐BINAP (80%). The transfer mechanism, either pore flow or solution‐diffusion, was discussed. All the results obtained suggested that the transport is governed by the solution‐diffusion mechanism. The measured retentions could be explained in terms of solubility affinities and diffusion coefficients. The stability and performances of PERVAP4060 were well established, showing the strong potential for industrial applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48359.

Volume intensified dilution of a ring‐closing metathesis in ethyl acetate by means of a membrane‐assisted process in solvent recycle

AbstractBACKGROUNDRing‐closing metathesis (RCM) for the synthesis of macrocycles has been used more and more often over recent years, including some interesting applications on industrial scale. However, like all macrocyclization strategies RCM is plagued by the traditional issue of low volume efficiency. To‐date this is typically addressed in a molecule specific manner with varying degrees of success. Here we report a process intensification method of metathesis macrocyclization that reduces the solvent load required for the reaction significantly.RESULTSMetathesis macrocylizations were successfully carried out in a solvent volume of upto 82% lower than an equivalent batch reaction, with only minimal impact upon the reaction outcome. A switch of reaction solvent to ethyl acetate renders the process more benign and applicable to large scale.CONCLUSIONA membrane‐assisted processing method that relies upon organic solvent nanofiltration permitting an internal solvent recycling and concumittent in situ product removal. The method is also designed to be applicable to a wide range of metathesis cyclizations. © 2019 Society of Chemical Industry

Deep eutectic solvent promoted hydrothiocyanation of alkynoates leading to Z-3-thiocyanatoacrylates

A mild and efficient protocol for the selective construction of Z-3-thiocyanatoacrylates is described. Various alkynoates reacted with KSCN and H2O by using cheap and recyclable deep eutectic solvent as the catalyst and reaction media to produce the corresponding products in excellent yields with mild reaction conditions and wide substrate scope.

Cleaner and sustainable approach of washing oil sands using CO2-responsive composite switchable water (CSW) with lower volatility

Abstract Switchable-Hydrophilicity Solvent (SHS) with high volatility is obstruct to environmental protection and solvent recycling in extraction process. This research aims at providing a cleaner and more sustainable approach of washing oil sands by using the CO2-responsive Composite Switchable Water (CSW). This CSW was prepared by Di-n-propylamine (DPA), N,N-dimethylethanolamine (DMEA) and water. The formation of CSW is attributed to the interaction between DPA and DMEA, which was detected by nuclear magnetic resonance hydrogen spectrum (1HNRM). The different CO2 switchable behaviors of CSW were demonstrated by the variety of conductivity and pH. Although DPA belongs to one of the SHS with high toxicity and volatility, the resulting CSW represents much lower volatility and more stability at room temperature and ambient pressure. The results show that the oil content of oil sands reduces to 2.36 wt% by using CSW with the volume ratio of 2 : 3 between DPA and DMEA aqueous solution (the volume ratio between DMEA and water is 1 : 1). Fourier Transform Infrared Spectroscopy (FT-IR) was used to demonstrate the removing of oil from the sands after being treated with CSW. The reversible change of conductivity shows the recycling ability of CSW. Finally, the economic and environmental value of washing oil sands with CSW was calculated.

Polyethylene glycol (PEG-400) promoted one-pot, five-component synthesis of (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)-4-oxothiazol-5(4H)-ylidene)acetates.

A facile, inexpensive and eco-friendly synthesis of functionalised (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)14-oxothiazol-5(4H)-ylidene)acetates has been developed via one-pot five-component approach. The title compounds were synthesized by the reaction of anilines, 3-chloropentane-2,4-dione, ammoniumthiocyanate, thiosemicarbazide and dialkylacetylene dicarboxylate using polyethylene glycol as green and recyclable solvent. The domino reaction proceeded smoothly in good-to-excellent yields.

Design of a Portable Soil Analysis Instrument for Remote Teleoperated Rover Platforms

The search for extant life has long been an interest since people have been able to successfully explore other worlds. However, on space missions, experiments must be performed autonomously, with limited resources, and a carefully selected suite of instruments. Instruments are additionally constrained by weight, reliability, and size which limits use of many modern advanced systems. The Queen’s Space Engineering Team (QSET) is proposing the design of a portable (12” x 12” x 12”) instrument to identify signs supporting extant life aboard a mobile rover platform during exploration missions. The instrument will receive soil samples collected by the rover, analyse the composition to identify key molecules, and transmit data back to a ground station. This system relies on colorimetric measurements using a UV-VIS spectrometer and features a solvent recycle system to minimize weight and waste. This project is part of a larger environment characterisation module to be mounted on a Mars rover system designed for competition at the University Rover Challenge (URC) at the Mars Desert Research Station (MDRS) in Utah. As of this date, each subsystem has successfully passed performance testing and the entire instrument is entering its system-level prototyping stage.

Cover Feature: Sustainable Asymmetric Organolithium Chemistry: Enantio‐ and Chemoselective Acylations through Recycling of Solvent, Sparteine, and Weinreb “Amine” (ChemSusChem 6/2019)

Cover Feature: Sustainable Asymmetric Organolithium Chemistry: Enantio‐ and Chemoselective Acylations through Recycling of Solvent, Sparteine, and Weinreb “Amine” (ChemSusChem 6/2019)

Low melting mixture glycerol:proline as an innovative designer solvent for the synthesis of novel chromeno fused thiazolopyrimidinone derivatives: An excellent correlation with green chemistry metrics

The expansion of proficient and environmentally benign synthetic protocols has engrossed increasing attention in recent organic syntheses in view of the mounting concern over the environment. As part of this green concept, our group designed novel LTTM by using Glycerol and proline (1:1) at reflux condition, and effectiveness of novel DES or LTTM has been studied for the synthesis of 7-(aryl)-10-methyl-6H,7H-chromeno[4,3-d]thiazolo[3,2-a]pyrimidin-6-one derivatives via Multicomponent reaction. The synthetic methodology with the use of novel LTTM as green solvent and inexpensive, biodegradable, plays a dual role (recyclable catalyst and solvent) with its operational simplicity and maximum greener synthetic efficiency with green chemistry metrics calculations will be attractive for academic and industrial research. The synthesized derivatives have been evaluated for mosquito larvicidal bioassay using two mosquito species namely Aedes aegypti and Culex quinquefasciatus.

Deep eutectic solvent for an expeditious sono-synthesis of novel series of bis-quinazolin-4-one derivatives as potential anti-cancer agents.

To produce a new category of anti-cancer compounds, a facile and environmentally sustainable method for preparing diversified bis-quinazolinones was demonstrated using recyclable deep eutectic solvent (DES) under ultrasonic irradiation. The reactions were performed smoothly with a wide scope of substrates affording the desired derivatives in good-to-excellent yields under an atom-economical pathway. Particularly, halogen substituents that are amenable for further synthetic elaborations are well tolerated. Furthermore, the ‘greenness’ of the protocol was assessed within the scope of several green metrics and found to display an excellent score in the specified parameters. Cytotoxic activity of all novel bis-quinazolinones was investigated utilizing two cancer cell lines: breast (MCF-7) and lung (A549) cell lines and their IC50 values were determined. Most of the prepared derivatives displayed fascinating inhibitory activity with IC50 values in a low micromolar range. Remarkably, the derivative 7e [3,3'-(sulfonylbis(4,1-phenylene))bis(2-methyl-6-nitroquinazolin-4(3H)-one)] showed superior potency against MCF-7 and A549 cancer cell lines, with IC50 values of 1.26 µM and 2.75 µM, respectively. Moreover, this derivative was found to have low toxicity to the normal breast cell line (MCF-10A) and could serve as a promising lead candidate for further development.