Tetrahydrofuran Extraction Research Articles

Biodegradation of 1,4-dioxane by Rhodanobacter AYS5 and the role of additional substrates

The present study details about the biodegradation of 1,4-dioxane by Rhodanobacter AYS5 isolated from bacterial consortia enriched from industrial sludge. Rhodanobacter AYS5 potently degraded 95 % of 1,4-dioxane (1000 ppm) in 10 days as sole carbon source. To accelerate the growth of Rhodanobacter AYS5 and to reduce the time taken for degradation, additional carbon source (glucose, yeast extract and tetrahydrofuran) were added and analysed. The study revealed that, yeast extract and tetrahydrofuran (THF) accelerated the degradation of 1,4-dioxane by reducing the time taken for degradation. Growth on glucose reduced the degradation potential of the bacterial strain. Study on carbondioxide evolution and metabolites formation confirmed complete mineralisation of 1,4-dioxane by Rhodanobacter AYS5. Further study on different concentration of 1,4-dioxane with and without additional substrate (THF and yeast extract) revealed that, Rhodanobacter AYS5 is a promising bacterial strain for 1,4-dioxane degradation. In lab scale reactor study with industrial wastewater, Rhodanobacter AYS5 showed 91 % chemical oxygen demand (COD) removal, and complete degradation of 1,4-dioxane and THF in 5 days. The 1,4-dioxane degrading bacterial strain was identified as Rhodanobacter AYS5 (JQ419753) using molecular and biochemical techniques.

Effect of tetrahydrofuran extraction on lignite pyrolysis under nitrogen

Based on the host-guest model of coal, the fixed and mobile phase of coal which can be separated by solvent extraction will present different characteristics during thermal conversion. The pyrolysis of Xilinguole and Huolinhe lignites and their extraction residues with tetrahydrofuran were investigated at 450–700°C under N2 atmosphere. The results indicate that the temperature at the maximum tar yield of extraction residue is lower than that of coal. Compared with raw coal, residue pyrolysis process exhibits lower water yield, higher gas yield and similar char yield. Similar H2 yield, more CO and CO2 yields but less CH4 yield are obtained during residue pyrolysis than those in coal pyrolysis. GC analysis of tar shows that contents of phenols and mononuclear aromatics from residue tar are higher than those from raw coal tar. 1H NMR and 13C NMR of tar indicate that the tar from residue has higher aromaticity factor than that from coal. The total acidity and acid distribution in raw coal, extraction residue and their chars obtained at 600°C show that phenolic OH is the main oxygen contained group in extract. The activity of O in coal could be improved by extraction, and more O will be translated to OH during pyrolysis.

Pyrolysis of Huolinhe lignite extract by in-situ pyrolysis-time of flight mass spectrometry

In this paper, tetrahydrofuran extract of Huolinhe lignite was selected as sample and a new in-situ pyrolysis-time of flight mass spectrometry (PY-TOF-MS) was used to study the evolution of initial pyrolysis products of extract. Electron impact mass spectrometry (EI-MS) and vacuum ultraviolet photoionization mass spectrometry (VUV-PI-MS) were used to detect different pyrolysis products. The similarity of DTG curve and ion counts of PY-TOF-MS shows the good performance of the equipment in coal pyrolysis. EI-MS results show that the oxygen containing gases present multiple peaks; however, H2 and CH4 present single evolution peak. More evolution peak numbers of CO2 and H2O in extract pyrolysis than that of coal show that extract has more advantages to investigate the formation mechanisms of CO2 and H2O. VUV-PI-MS is proved to be a useful method to analyze tar components. The aliphatics and aromatics in initial products have relatively larger molecular weight than those of the low boiling point substances in extract. The polycyclic aromatic hydrocarbons have an increasing tendency with ring number. Phenols exhibit different evolution curves, and C7H8O and C8H10O are dominant compounds. These results illustrate that different initial products have different formation mechanisms and oxygen atom plays an important role during pyrolysis.

Partitioning of elements from coal by different solvents extraction

Mixed samples of the whole seam and coal ply sample #1, 3, 9, 10, 14, 19, and 23 of the No. 11 coal seam from the Antaibao mining district, Shanxi, China were conducted by the sequential chemical, carbon disulfide/N-methyl-2-pyrrolidone (CS2/NMP) mixed solvent, and fractional (methanol, benzene, acetone and tetrahydrofuran (THF)) extraction experiments. More than 30 major and trace elements in the coal samples and resultant extracts were determined by means of instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectroscopy (ICP-MS) and atomic fluorescence spectrometry (AFS) in order to investigate their partitioning during the extraction. The results show that: (1) generally, an element with a higher content in coal is relatively enriched in organic solvent extracts of the coal, though its content in the extracts is significantly lower than that in the original coal. However, some elements occurring as organic phase like Br, Mo, Ni, Sb and Se are relatively enriched in the extracts; (2) the contents of most studied elements in different organic solvent extracts of coal are positively correlated with the polarity of solvent, i.e. most elements have the highest content in the methanol extract, higher in the acetone and THF extracts, and the lowest in the benzene extract in the order of the solvent polarity; (3) most studied elements have the highest extraction rate by sequential chemical extraction, higher by CS2/NMP mixed solvent extraction, and the lowest by fractional extraction. The difference in extraction rate could reflect the affinity of elements with small or large organic molecules in coal. In detail, elements Al, As, Co, Cr, Ni, and Zn more enriched in the fractional extracts have a higher affinity with small molecules, while the other studied elements are more related to larger molecules.

Extraction of Tetrahydrofuran and Ethylene Dichloride Solvents from Aqueous Solutions by Pervaporation through Thin Film Composite PDMS Membranes

Thin film composite (TFC) hydrophobic PDMS membrane of 5 µm active layer thickness supported on Polyethersulfone (PES) ultraporous substrate was synthesized and thermally crosslinked for the pervaporation based extraction of organic solvents such as Tetrahydrofuran (THF) and Ethylenedichloride (EDC) for the first time. The study was extended to acetone, ethanol, t-butanol, Iso-butanol, and acetic acid. Membranes were characterized by SEM, TGA, XRD, and FTIR to study the surface and cross-sectional morphology, thermal stability, crystalline nature, and structural properties, respectively. High selectivities of 868, 72, and 31 were observed at organic feed concentrations of 0.68, 3.42, and 9.38 wt% in water with reasonable fluxes of 0.2, 0.16, and 0.31 kg m−2 h−1 for EDC, THF and acetone, respectively at a downstream vacuum of 0.5 mmHg. The estimated mass transfer coefficients (MTCs) were found to be 9.11 × 10−6, 11.77 × 10−6, and 10.73 × 10−6 m s−1 for THF, EDC, and acetone extraction, respectively. The membrane exhibited considerable feasibility for scale-up due to its composite nature with significant potential for extraction of volatile organic solvents present in low concentrations. A comparison with previous values reported in literature revealed higher selectivities for extraction of EDC, THF and acetone using the present membrane.

Production of all trans-beta-carotene by using impinging flow of supercritical carbon dioxide anti-solvent pulverization

This work investigated column elution chromatography coupled with supercritical anti-solvent precipitation to produce carotenoid rich microsized particulates from microalgal Dunaliella salina species. The extract contained carotenoids ranging from 61.3mg/gsalina to 72.5mg/gsalina using ultrasonic stirred ethyl ether or tetrahydrofuran (THF) extraction. When 10L of ethyl alcohol was employed to elute the THF extract, purity of trans-β-carotene is 823.6mg/g with a recovery of 86.2%. It was found that the supercritical anti-solvent of THF solution at 160bar and 318K produced powdered particulates with a purity of carotenoids above 90%. Subsequently, a central composite response surface design method was used to design supercritical anti-solvent precipitation of carotenoid-rich THF solution. This was accomplished by increasing the pressure from 140bar to 180bar and the time from 40min to 60min at a feed flow rate of 0.2mL/min. A CO2 flow rate of 15L/min and a temperature of 318K were also used to determine the effects on purity and recovery of trans-β-carotene. The combined process produced micronized precipitates with a mean particle size ranging from 3.5μm to 19μm and the purity of trans-β-carotene attained was 926.8mg/g with a recovery of 54%.

Isolation and identification of low molecular weight carboxylated carbons derived from the nitric acid treatment of single-walled carbon nanotubes

Single-walled carbon nanotubes (SWCNTs) were purified by treatment with concentrated nitric acid and then subjected to Soxhlet extraction with tetrahydrofuran (THF). The THF extract of low molecular weight carboxylated carbons was derivatized with (trimethylsilyl)diazomethane and the resulting methylated material was separated with column chromatography and thin layer chromatography and several fractions were identified by GC–MS and 1H NMR. The fractions were shown to include small benzopolycarboxylic acids and organic nitro compounds.

Determination of UV filters in packaging by focused ultrasonic solid–liquid extraction and liquid chromatography

A focused ultrasonic solid–liquid extraction (FUSLE) and high performance liquid chromatography (HPLC) with a diode array detector (DAD) is proposed for the determination of ten fat-soluble UV filters in packaging. FUSLE technique is relatively new and has been used for the extraction of a few analytes; such as polycyclic aromatic hydrocarbons and other organic pollutants. In this work, it has been demonstrated that FUSLE is a useful, fast and simple extraction methodology for UV filters because the complete extraction was carried out with just 6 ml of tetrahydrofuran and in only one cycle of 30 s. The developed method has been validated and applied to the analysis of polyethylene-based multilayer packaging samples. The FUSLE-based method allows the sensitive detection of most of the UV-filters in polyethylene, with limits of detection between 0.4 and 8.5 ng mg −1 (except for BDM). Intra and inter-day relative standard deviation values were below 5 and 14%, respectively, except for MBP. In addition, the proposed method was more efficient than tetrahydrofuran extraction under reflux for 2.5 h for all the analytes except for EMT and BDM. Therefore, the developed method can be used to establish the absorption capability of different types of packaging and this information will be very useful in packaging selection.

Efficient whole-cell biotransformation of 5-(hydroxymethyl)furfural into FDCA, 2,5-furandicarboxylic acid

2,5-Furandicarboxylic acid (FDCA) is a promising bio-based platform chemical that may serve as a ‘green’ substitute for terephthalate in polyesters. Recently, a novel HMF/furfural oxidoreductase from Cupriavidus basilensis HMF14 was identified that converts 5-(hydroxymethyl)furfural (HMF) into FDCA. The hmfH gene encoding this oxidoreductase was introduced into Pseudomonas putida S12 and the resulting whole-cell biocatalyst was employed to produce FDCA from HMF. In fed-batch experiments using glycerol as the carbon source, 30.1 g l −1 of FDCA was produced from HMF at a yield of 97%. FDCA was recovered from the culture broth as a 99.4% pure dry powder, at 76% recovery using acid precipitation and subsequent tetrahydrofuran extraction.

Classification of OPP adhesive tapes according to MALDI mass spectra of adhesives

Classification of acrylic and rubber-based pressure sensitive adhesives (PSAs) of colorless and transparent oriented polypropylene adhesive tapes distributed in Japan according to matrix-assisted laser desorption/ionization (MALDI) mass spectrum has been studied. MALDI mass spectra of acrylate oligomers and emulsifiers were observed from tetrahydrofuran extracts of acrylic PSAs, and aliphatic petroleum resin, aliphatic–aromatic copolymer and unknown additives were from 2-butanone extracts of rubber-based PSAs. Acrylic PSAs were classified into 10 groups and rubber-based PSAs were into 8 groups. The criteria for the classification according to the MALDI mass spectrum were clearer than according to FT-IR spectrum.

Environmental responses of nanostructured polyaniline films based on polystyrene–polyaniline core–shell particles

This paper describes a simple method for fabricating nanostructured polyaniline (PANI) films from polystyrene (PS)–PANI core–shell particles and the environmental responses of the films. Monodisperse PS latex particles synthesized via surfactant-free emulsion polymerization were used as cores, onto whose surface aniline monomers adsorbed with the aid of sodium dodecyl sulfate and were polymerized by adding ammonium peroxydisulfate. The resulting suspensions of core–shell particles were then drop-cast onto substrates and dried. Films composed of fragments of thin PANI shells of tens of nanometers were obtained after the removal of PS by tetrahydrofuran extraction. Another kind of films was prepared by heating the core–shell particles above the glass transition temperature of PS for a short time before the extraction. The morphology was observed using scanning electron microscopy, and the UV–vis spectra were recorded by a spectrometer. Furthermore, we examined the resistance responses of the films to dry gas flow, ethanol vapor, hydrogen chloride, and ammonia. The high sensitivity and fast response should be due to the large surface area interacting with analytes and porosity that facilitates diffusion. In addition, the effect of the packing of PANI shells in the films on the responses was discussed.

Preparation and properties investigation of PMMA/silica composites derived from silicic acid

AbstractHybrid materials based on silicic acid and polymethyl methacrylate (PMMA) were prepared by in situ bulk polymerization of a silicic acid sol and MMA mixture. Silicic acid sol was obtained by tetrahydrofuran (THF) extraction of silicic acid from water. Silicic acid was prepared by hydrolysis and condensation of sodium silicate in the presence of 3.6 M HCl. As a comparative study, PMMA composites filled by silica particles, which were derived from calcining the silicic acid gel, were prepared by a comparable in situ polymerization. Each set of PMMA/silica composites was subjected to thermal and mechanical studies. Residual THF in PMMA/silicic acid composites impacted the properties of the polymer composites. With increase in silica content, the PMMA composites filled with silica particles showed improved thermal and mechanical properties, whereas a decrease in thermal stability and mechanical strength was found for PMMA composites filled with silicic acid dissolved in THF. With a better compatibility with polymer matrix, silicic acid sol shows better reinforcement than silica particles in PMMA films prepared via blending of the corresponding THF solutions. Copyright © 2008 John Wiley & Sons, Ltd.

SiO2 Reinforced EVM/TPU Blends: Bound Rubber and Rheology Behavior

Silica is shown to be a more active filler than carbon black for the reinforcement of EVM/TPU blends. The static rheology of EVM/TPU blends is considerably influenced by a tightly bound rubber structure developing between the TPU and silica that was identified by a tetrahydrofuran extraction test and SEM observations. Dynamic rheology behavior corroborated the development of bound rubber and indicated the existence of the Payne effect because of filler-filler networks in the blends. The silica-TPU interaction is thermally unstable at 190°C and mechanically unstable at a shear frequency of 1 Hz.

Comparison of tetrahydrofuran and ethyl acetate as extraction solvents for urinary organic acid analysis

The analysis of urinary organic acids is crucial for the diagnosis of many inborn errors of metabolism. A vital part of the analytical process is the extraction procedure. The sensitivity and linearity of the analysis of 26 diagnostically important urinary metabolites with tetrahydrofuran (THF) and ethyl acetate (EtOAc) as extraction solvents were determined by gas chromatography-mass spectrometry. Good linearity (r (2) > 0.90) was observed for all of the compounds in the investigated concentration range (290-900 mumol/L) for both solvents. For less polar compounds, THF extraction yielded lower or similar sensitivities as compared with EtOAc (sensitivity ratio: 0.6-1.3). For more polar compounds, however, much higher sensitivities were observed when THF was used (sensitivity ratio: 1.8-17.2). Our results provide information concerning the use of THF for the sensitive quantitative analysis of polar urinary metabolites which are difficult to quantify using EtOAc.

ＨＰＬＣ法を用いた加硫ゴム中の遊離硫黄の定量

A new quantitative analytical method to determine the free sulfur content in vulcanized natural rubber was proposed. This method, i. e. a combination of tetrahydrofuran (THF) extraction followed by HPLC analysis in size exclusion chromatography mode, required much less sample compared with that needed in the ordinary sodium sulfite method specified by JIS K 6234 and ASTM D297. The detectable sensitivity of the new method was about hundreds times of the former method. In addition, it was proven that only free sulfur content could be determined by this method whereas the sum of the free sulfur and polysulfide contained in the rubber sample was detected by the ordinary sodium sulfite method.

Self-organized Multilayer Films and Porous Nanocomposites of Gold Nanoparticles with Octa(3-aminopropyl)octasilsesquioxane

Successive deposition of octa(3-aminopropyl)octasilsesquioxane octahydrochloride and gold nanoparticles coated with carboxylate groups (Au–COO−) on glass substrates alternately under mild basic conditions led to systematic buildup of a gold colloidal multilayer. The driving force of the self-assembly was electrostatic interaction between ammonium cations of octa(3-aminopropyl)octasilsesquioxane octahydrochloride and carboxylate anions on Au–COO−. A linear increase of surface plasmon resonance of Au–COO− with the deposited bilayers indicated the multilayer manipulation was reproducible. Porous nanocomposites were accomplished by precipitation of octa(3-aminopropyl)octasilsesquioxane octahydrochloride modified polystyrene (PS) latex particles and Au–COO− followed by removal of the PS particles via tetrahydrofuran (THF) extraction. Porous nanocomposite films were obtained by layer-by-layer (LBL) self-assembly of the octa(3-aminopropyl)octasilsesquioxane octahydrochloride modified PS latex particles and Au–COO− followed by removal of the PS particles via THF extraction.

Phase equilibria for ternary liquid systems of (water + tetrahydrofuran + nonprotic aromatic solvent) at T = 298.2 K

(Liquid + liquid) equilibrium (LLE) data of the solubility curves and tie-line end compositions are presented for mixtures of {water (1) + tetrahydrofuran (2) + xylene or chlorobenzene or benzyl ether (3)} at T = 298.2 K and P = (101.3 ± 0.7) kPa. Among the studied C6 ring-containing aromatic solvents, xylene gives the largest distribution ratio and separation factors for extraction of tetrahydrofuran. A solvation energy relation (SERLAS) has been used to estimate the (liquid + liquid) equilibria of associated systems containing a nonprotic solvent. The tie-lines were also predicted using the UNIFAC-original model. The reliability of both models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. SERLAS matches LLE data accurately, yielding a mean error of 9.9% for all the systems considered.

Liquid−Liquid Equilibria for the Ternary Systems of (Water + Tetrahydrofuran + Polar Solvent) at 298.15 K

Liquid−liquid equilibrium data and tie-line end compositions are presented for mixtures of [water (1) + tetrahydrofuran (2) + trichloroethylene or + 1-hexanol or + 3-methylbutyl ethanoate (3)] at T = 298.15 K and P = (101.3 ± 0.7) kPa. Among the studied solvents, 3-methylbutyl ethanoate represents the best performance for the extraction of tetrahydrofuran. The properties and liquid−liquid equilibria (LLE) of the associated ternaries containing polar components capable of hydrogen bonding or dipole−dipole interaction have been estimated using a solvatochromic approach (SERLAS). The tie lines were also correlated using the UNIFAC-original model. The reliability of the models has been analyzed against the LLE data with respect to the distribution ratio and separation factor. The proposed solvatochromic model appears to be an improvement in data fit for the ternary systems, yielding a mean error of 15% for all the systems considered.

Initial coke deposition on hydrotreating catalysts. Part 1. Changes in coke properties as a function of time on stream

Initial coke deposition on an industrial Mo/Al 2O 3 hydrodemetallization catalyst was studied as a function of operating time during hydrotreating of Kuwaiti atmospheric residue ( T; 380 °C, LHSV; 1 h −1). The primary objective of the study was to examine the nature of the initial coke and to determine coke's possible role in catalyst deactivation. The amount of coke on the catalyst increased rapidly and climbed up to 15 wt% within 12 h, but then, coke formation slowed down and reached about 20 wt% after 240 h. Used catalyst samples from experiments conducted at different time on stream periods (1, 3, 12, 48, 120 and 240 h) were subjected to temperature programmed oxidation and diffuse reflectance infrared Fourier transform spectroscopy to obtain information on the nature of the initial coke and changes in the coke properties with increasing run time. Additionally, the 1, 12, 48 and 120 h aged catalysts were extracted with tetrahydrofuran (THF). The results showed the presence of two types of coke on the catalyst, an easy removable soft coke and a more refractory surface coke. After 240 h of operation, a large fraction of the soft coke had been converted into refractory coke. The refractory coke contained substantial amounts of nitrogen and sulfur, whereas their concentration in soft coke was rather low. Nitrogen species, e.g. NH x , were found to deposit at the active metal sulfide crystallites, whereas coke was formed predominantly at the surface of the support. The THF extraction removed mainly heterocompounds and aliphatic coke components.

Application of styrene‐acrylonitrile random copolymer–polyarylate block copolymer as reactive compatibilizer for polyamide and acrylonitrile‐butadiene‐styrene blends

AbstractStyrene‐acrylonitrile random copolymer (SAN) and polyarylate (PAr) block copolymer were applied as a reactive compatibilizer for polyamide‐6 (PA‐6)/acrylonitrile‐butadiene‐styrene (ABS) copolymer blends. The SAN–PAr block copolymer was found to be effective for compatibilization of PA‐6/ABS blends. With the addition of 3.0–5.0 wt % SAN–PAr block copolymer, the ABS‐rich phase could be reduced to a smaller size than 1.0 μm in the 70/30 and 50/50 PA‐6/ABS blends, although it was several microns in the uncompatibilized blends. As a result, for the blends compatibilized with 3–5 wt % block copolymer the impact energy absorption reached the super toughness region in the 70/30 and 50/50 PA‐6/ABS compositions. The compatibilization mechanism of PA‐6/ABS by the SAN–PAr block copolymer was investigated by tetrahydrofuran extraction of the SAN–PAr block copolymer/PA‐6 blends and the model reactions between the block copolymer and low molecular weight compounds. The results of these experiments indicated that the SAN–PAr block copolymer reacted with the PA‐6 during the melt mixing process via an in situ transreaction between the ester units in the PAr chain and the terminal amine in the PA‐6. As a result, SAN–PAr/PA‐6 block copolymers were generated during the melt mixing process. The SAN–PAr block copolymer was supposed to compatibilize the PA‐6 and ABS blend by anchoring the PAr/PA‐6 and SAN chains to the PA‐6 and ABS phases, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2300–2313, 2002