Mixed Solvent Of Acetone Research Articles

Novel method for the prediction of distribution and elution characteristic of several drugs in cellulose diacetate-water system: Interaction between mixed solvent and cellulose diacetate

Drug-loaded cellulose diacetate (CDA) membranes were prepared by dissolving cellulose diacetate in a mixed solvent of acetone and ethanol, adding the drug to it, pouring it on a glass plate and evaporating the solvent. In this study, it was prepared CDA membranes varying composition of the mixed solvent (the mass ratio of acetone (ACE) to ethanol (EtOH)) and investigated their microstructure and performance.The release properties of drugs in drug-loaded CDA membranes were examined in correlation with the composition of the mixed solvent and a method to be able to predict the release properties of drugs was proposed. Penicillin G potassium, streptomycin sulfate and ampicillin were used as drugs. The microstructure of the membranes was determined using SEM analysis and the release properties of drugs were measured using spectrofluorophotometer. It was shown that the composition of the mixed solvent can have a significant effect on the overall performance of CDA membrane. The intrinsic viscosity measurements and solubility parameter analysis proved that the intrinsic viscosity of CDA in polymer solutions with mixed solvents and the solubility parameter difference (Δδ) between mixed solvents and CDA were relative with the release properties of drugs. The release rates of drugs from the membrane related to △δ directly and the intrinsic viscosity inversely. Therefore, the release rates of drugs from CDA membrane can be controlled by changing the composition of the solvent used for the preparation of the polymer membrane.

Effect of Solvent Treatment on the Composition and Structure of Santanghu Long Flame Coal and Its Rapid Pyrolysis Products.

Easily soluble organic components in Santanghu long flame coal (SLFC) from Hami (Xinjiang, China) were separated by CS2 and acetone mixed solvent (v/v = 1:1) under ultrasonic condition, and the extract residue was stratified by carbon tetrachloride to obtain the light raffinate component (SLFC-L). The effect of solvent treatment on the composition and structure of the coal and its rapid pyrolysis products was analyzed. Solvent treatment can reduce the moisture content in coal from 9.48% to 6.45% and increase the volatile matter from 26.59% to 28.78%, while the macromolecular structure of the coal changed slightly, demonstrating the stability of coal's complex organic structure. Compared with raw coal, the relative contents of oxygen-containing functional groups and aromatic groups in SLFC-L are higher, and the weight loss rates of both SLFC and SLFC-L reached the maximum at about 450 °C. In contrast, the loss rate of SLFC-L is more obvious, being 33.62% higher than that of SLFC. Pyrolysis products from SLFC at 450 °C by Py-GC/MS are mainly aliphatic hydrocarbons and oxygenated compounds, and the relative contents of aliphatic hydrocarbons decreased from 48.48% to 36.13%, while the contents of oxygenates increased from 39.07% to 44.95%. Overall, the composition and functional group in the coal sample were changed after solvent treatment, resulting in a difference in the composition and distribution of its pyrolysis products.

Structure and Vibrational Spectra of Pyridine Solvated Solid Bis(Pyridine)silver(I) Perchlorate, [Agpy2ClO4]·0.5py

A hemipyridine solvate of bis(pyridine)silver(I) perchlorate, [Agpy2ClO4]·0.5py (compound 1) was prepared and characterized by single crystal X-ray analysis and vibrational spectroscopy (R and low-temperature Raman). Compound 1 was prepared via the trituration of [Agpy2ClO4] and 4[Agpy2ClO4]·[Agpy4]ClO4 (as the source of the solvate pyridine) in a mixed solvent of acetone:benzene =1:1 (v = v) at room temperature. The monoclinic crystals of compound 1 were found to be isomorphic with the analogous permanganate complex (a = 19.1093(16) Å, b = 7.7016(8) Å, c = 20.6915(19) Å, β = 105.515(7)°; space group: C2/c). Two [Agpy2]+ cations formed a dimeric unit [Agpy2ClO4]2, and each silver ion was connected to two ClO4− anions via oxygen atoms. The Ag∙∙∙Ag distance was 3.3873(5) Å, the perchlorate ions were coordinated to silver ions, and the Ag∙∙∙O distances were 2.840(2) Å and 2.8749(16) Å in the centrosymmetric rectangle of Ag-O-Ag-O. The stoichiometric ratio of the monomer [Agpy2ClO4] and the solvent pyridine was 1:0.5. The guest pyridine occupied 527.2 Å3, which was 18.0% of the volume of the unit cell. There was no additional residual solvent-accessible void in the crystal lattice. The solvate pyridine was connected via its a-CH to one of the O atoms of the perchlorate anion. Correlation analysis, as well as IR and low-temperature Raman studies, were performed to assign all perchlorate and pyridine vibrational modes. The solvate and coordinated pyridine bands in the IR and Raman spectra were not distinguishable. A perchlorate contribution via Ag-O coordination to low-frequency Raman bands was also assigned.

Advances in Research at Synthesis Process Optimization and Quality Standard Improvement of O-desmethylvenlafaxine Succinate.

We herein describe an optimal approach for the efficient synthesis of O-desmethylvenlafaxine succinate monohydrate (DVS) with high yield and high purity through 5-step reactions, including benzyl protection of the phenolic hydroxyl group, cyclohexanone condensation, deprotection, cyano reduction, dimethylation, and succinic acid salt formation from p-hydroxybenzene acetonitrile as a starting material. 4-Benzyloxyphenylacetonitrile (Intermediate I) was prepared by the hydroxyl protection of the bromide benzyl-p-hydroxyphenylacetonitrile catalyzed by potassium carbonate with 99.83% purity and 98.92% yields. The 1, 2-nucleophilic addition of intermediate I to cyclohexanone promoted by sodium hydroxide with the homogeneous catalyst (n-Bu)4N+Br− to the preparation of 1-[Cyano(4-benzyloxyphenyl)methyl]cyclohexanol (Intermediate II) was obtained by 99.13% purity and 99.71% yields. Cyclohexanone residues and benzyl bromide residues were trace, and tetrabutylammonium bromide residues were UNDER 0.7 ppm, which further improves the residual standards for genotoxic impurities (GIs). 1-[2-amino-1-(4-hydroxyphenyl)ethyl]cyclohexanol hydrochloride (Intermediate III) was prepared by 10% palladium-carbon under 2.0 MPa up to 98.32% purity and 94.20% yields. O-desmethylvenlafaxine (ODV) was synthesized by dimethylation of intermediate III with 37% formaldehyde solution and 85% formic acid solution. The highest purity was up to 99.20% and the yield was up to 84.77%. O-desmethylvenlafaxine succinate monohydrate (DVS) was formed from succinic acid and O-desmethylvenlafaxine (ODV) and crystallized in a mixed solvent of acetone and water (3:1) to obtain 99.92% purity and 90.27% yields. The 5-step total yields of desvenlafaxine succinate monohydrate is 71.09%, and its crystal form has characteristic peaks at 5, 10, 21, and 26 min by XRD powder diffraction, which is consistent with the crystalline form I. Compared with conventional synthesis strategy, we revealed a novel and green process with a high total yield, high atomic economy, low environmental pollution, high operational safety, and high residual standards for genotoxic impurities (GIs), which improves drug safety.

Investigation on the growth, structural, optical, thermal and third-order nonlinear optical (NLO) properties of 2,3-dimethyl-N-[(E)-2,4,5-trimethoxybenzylidene] aniline (DTA) organic single crystal

Good-quality organic nonlinear single crystal of 2,3-dimethyl-N-[(E)-2,4,5-trimethoxy benzylidene] aniline (DTA) was synthesized and successfully grown at room temperature by adapting slow evaporation technique using mixed solvent of acetone and methanol. The crystal structure was experimentally confirmed by single-crystal X-ray diffraction, where the DTA crystals crystallize in the centric space group (P $$\overline{1}$$ ) with triclinic crystal system. The surface morphology of DTA was examined by the Field Emission Scanning Electron Microscope (FE-SEM) technique. The presence of various modes of functional groups of the title crystal was analyzed by Fourier-Transform Infra-Red (FT-IR) spectra. Ultraviolet–Visible-Near Infrared (UV–Vis–NIR) spectrum showed high optical transparency of ~ 88% in the Vis and NIR region with a UV–Vis absorption edge of 390 nm. The result of photoluminescence studies suggests that the DTA crystal can be used as source material to exhibit green emission light. From thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, the melting point of the grown crystal was found to be 111 °C. The standard Z-Scan technique was employed to evaluate the third-order nonlinear optical properties of the DTA crystal. The obtained third-order nonlinear parameters were compared with few of the already reported NLO crystals. All these findings indicate that the title crystal may be an attractive material for nonlinear optical device applications.

Processes to enhance the sensitivity of sensor for 2‐n‐octyl‐4‐isothiazolin‐3‐one as biocide

AbstractIn this study, hydraulic treatment was performed to fabricate porous cellulose acetate (CA) membranes for application as adsorbents for impurities. For this purpose, porous CA membranes were prepared by applying a water pressure of 8 bar on CA dissolved in a mixed solvent of acetone and water. These porous polymers could separate impurities from 2‐n‐octyl‐4‐isothiazolin‐3‐one (OIT) by providing adsorption surfaces for the suspended impurities and allowed pure OIT to filter through the membrane; the filtered OIT may subsequently be used for octyl‐group quantification. After impurity adsorption, the degree of OIT permeation in the CA membrane and the adsorption mechanism of CA were investigated by Fourier transform infrared spectroscopy and water‐adsorption studies. Further, we analyzed the porous characteristics and behavior of CA by scanning electron microscopy and conducted thermogravimetric analysis to observe the physical and chemical changes occurring in the polymers.

Green and effective catalytic hydroconversion of an extractable portion from an oil sludge to clean jet and diesel fuels over a mesoporous Y zeolite-supported nickel catalyst

A mesoporous Y zeolite (MPYZ)-supported nickel catalyst (Ni/MPYZ with 10% of Ni loading) was prepared by modifying deposition-precipitation (MDP) to uniformly disperse Ni nanoparticles (NNPs) onto MPYZ. An oil sludge (OS) was exhaustively extracted with isometric carbon disulfide and acetone mixed solvent to obtained the extractable portion (EPOS) in the yield of 90.6%. EPOS was subjected to the catalytic hydroconversion (CHC) over Ni10%/MPYZ at 160 °C under 5 MPa of initial hydrogen pressure (IHP) for 18 h in n-hexane to afford catalytically hydroconverted EP (EPCHC). The results show that alkenes, aromatics, and heteroatom-containing compounds (HACCs, some of which are also aromatics) in EPOS were completely converted to chain alkanes and cyclanes. Ni/MPYZ can effectively activate H2 to biatomic active hydrogen (H⋯H) and heterogeneously split H2 to relatively mobile H+ and immobile H− attached on the surface of Ni/MPYZ. The transfer of H⋯H and H+ to EPOS plays crucial roles in the CHC of EPOS. Such mechanisms are evidenced by the CHC of benzyloxybenzene over Ni/MPYZ. Ni10%/MPYZ maintained high activity for the CHC after 5 repeated cycles.

Structure Characterization and Solubility Analysis of the Existent Gum of the Fischer-Tropsch Synthetic Crude.

The existent gum content of the Fisher–Tropsch synthetic crude exceeded the standard seriously, affecting its transportation and use. To determine the structure of the existent gum extracted from the Fisher–Tropsch synthetic crude, elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS) were employed to determine the chemical structure of the gum. The Brown–Ladner method is used to calculate the average structural parameters and the average molecular formula of the existent gum. The results show that the existent gum of the Fisher–Tropsch synthetic crude is composed of heterocyclic aromatic hydrocarbons and short-carbon paraffins. Compared with petroleum gums and coal tar gums, the existent gum content of the Fisher–Tropsch synthetic crude has the characteristics of high aromaticity, short side chains, and nitrogen-containing heterocycles. After being oxidized, its aromaticity further increases, more closed loops are formed, and the side chain is further shortened. This is caused by a complex oxidation reaction during the oxidation process. Molecular dynamics simulation calculations were performed to reveal the T-stacked morphology of the existent gum of the Fisher–Tropsch synthetic crude in a mixed solvent of acetone and toluene.

Catalytic hydroconversion of soluble portion in the extraction from Hecaogou subbituminous coal to clean liquid fuel over a Y/ZSM-5 composite zeolite-supported nickel catalyst

A novel and highly active Y/ZSM-5 composite zeolite (YZCZ)-supported nickel bifunctional catalyst (Ni/YZCZ) was prepared using a modified deposition–precipitation method to uniformly disperse Ni nanoparticles (NNPs) onto YZCZ. Hecaogou subbituminous coal was exhaustively extracted with isometric carbon disulfide and acetone mixed solvent under ultrasonic irradiation to afford the extractable portion (EP) in the yield of 18.4%. EP was subjected to catalytic hydroconversion (CHC) in n-hexane over Ni/YZCZ under 5 MPa of initial hydrogen pressure at 160 °C for 24 h to afford catalytically hydroconverted EP (CHCEP). Both EP and CHCEP were analyzed with a gas chromatograph/mass spectrometer (GC/MS) and quadrupole exactive orbitrap mass spectrometer (QPEOTMS). As a result, cyclanes, alkenes, and hydroarenes were only detected in CHCEP and the relative content (RC) of alkanes in CHCEP is much higher than that in EP, while the RCs of both arenes, especially condensed arenes, and oxygen-containing organic compounds in EP are predominantly higher than those in CHCEP and nitrogen-containing organic compounds were only detected in EP. According to the CHC of coal-related model compound oxydibenzene (ODB), Ni/YZCZ can effectively activate H2 to biatomic active hydrogen (H⋯H), which is then split to an immobile H− attached on Ni/YZCZ and a relatively mobile H+. The H⋯H transfer leads to the hydrogenation of aromatic rings (ARs) in EP and ODB followed by heteroatom removal from the hydrogenated EP and ODB. In addition, due to the appropriate acidity, uniformly dispersed NNPs, and mesoporous structure of YZCZ, Ni/YZCZ proved to be still active for the CHC after 3 cycles and recoverable.

Systems and methods for cracking hydrocarbon streams such as crude oils utilizing catalysts which include zeolite mixtures

A novel and highly active Y/ZSM-5 composite zeolite (YZCZ)-supported nickel bifunctional catalyst (Ni/YZCZ) was prepared using a modified deposition–precipitation method to uniformly disperse Ni nanoparticles (NNPs) onto YZCZ. Hecaogou subbituminous coal was exhaustively extracted with isometric carbon disulfide and acetone mixed solvent under ultrasonic irradiation to afford the extractable portion (EP) in the yield of 18.4%. EP was subjected to catalytic hydroconversion (CHC) in n-hexane over Ni/YZCZ under 5 MPa of initial hydrogen pressure at 160 °C for 24 h to afford catalytically hydroconverted EP (CHCEP). Both EP and CHCEP were analyzed with a gas chromatograph/mass spectrometer (GC/MS) and quadrupole exactive orbitrap mass spectrometer (QPEOTMS). As a result, cyclanes, alkenes, and hydroarenes were only detected in CHCEP and the relative content (RC) of alkanes in CHCEP is much higher than that in EP, while the RCs of both arenes, especially condensed arenes, and oxygen-containing organic compounds in EP are predominantly higher than those in CHCEP and nitrogen-containing organic compounds were only detected in EP. According to the CHC of coal-related model compound oxydibenzene (ODB), Ni/YZCZ can effectively activate H2 to biatomic active hydrogen (H⋯H), which is then split to an immobile H− attached on Ni/YZCZ and a relatively mobile H+. The H⋯H transfer leads to the hydrogenation of aromatic rings (ARs) in EP and ODB followed by heteroatom removal from the hydrogenated EP and ODB. In addition, due to the appropriate acidity, uniformly dispersed NNPs, and mesoporous structure of YZCZ, Ni/YZCZ proved to be still active for the CHC after 3 cycles and recoverable.

Study on recycling technology for waste MQ bonded Nd-Fe-B magnets

Abstract A simple method is introduced to obtain recycled Nd-Fe-B powders from waste bonded Nd-Fe-B bulk magnets. The main difficulty of the recovery of waste MQ bonded Nd-Fe-B magnets is how to remove the epoxy resins between the magnetic particles and the oxide impurities on the surfaces of the waste magnetic powders. Mixed solvents of acetone, Dimethyl Formamide and N-butyl alcohol were used to dissolve the epoxy resins. Oxide impurities were removed using 0.5% acetic acid/acetone solutions. After these treatments, the carbon and oxygen contents were reduced from 21,200 ppm to 9700 ppm, and from 11,007 ppm to 8177 ppm, respectively. Under optimum processing conditions, the recycled magnetic powders possess improved magnetic properties with Ms of 151.5 emu/g, Mr of 98.0 emu/g, Hcj of 7.1 kOe, and (BH)max of 13.7 MGOe. These values, compared to the waste magnetic powders, represent increases of 21.2%, 18%, 0 and 34.3%, respectively.

Creating Quasi Two-Dimensional Cluster-Assembled Materials through Self-Assembly of a Janus Polyoxometalate-Silsesquioxane Co-Cluster.

Clusters are an important class of nanoscale molecules or superatoms that exhibit an amazing diversity in structure, chemical composition, shape, and functionality. Assembling two types of clusters is creating emerging cluster-assembled materials (CAMs). In this paper, we report an effective approach to produce quasi two-dimensional (2D) CAMs of two types of spherelike clusters, polyhedral oligomeric silsesquioxanes (POSS), and polyoxometalates (POM). To avoid macrophase separation between the two clusters, they are covalently linked to form a POM-POSS cocluster with Janus characteristics and a dumbbell shape. This Janus characteristics enables the cocluster to self-assemble into diverse nanoaggregates, as conventional amphiphilic molecules and macromolecules do, in selective solvents. In our study, we obtained micelles, vesicles, nanosheets, and nanoribbons by tuning the n-hexane content in mixed solvents of acetone and n-hexane. Ordered packing of clusters in the nanosheets and nanoribbons were directly visualized using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) technique. We infer that the increase of packing order results in the vesicle-to-sheet transition and the change in packing mode causes the sheet-to-ribbon transitions. Our findings have verified the effectivity of creating quasi 2D cluster-assembled materials though the cocluster self-assembly as a new approach to produce novel CAMs.

Investigation of the dispersion behavior of fluorinated MWCNTs in various solvents.

The investigation of the dispersion behavior of fluorinated MWCNTs (F-MWCNTs) is very important to understand their structure and take full advantage of their good properties. In this present paper, the dispersion behavior of F-MWCNTs with a low content and a high content of fluorine (denoted as lF-MWCNTs and hF-MWCNTs) was explored in 18 kinds of common solvents. The surface of hF-MWCNTs is considered to be a heterostructure consisting of fluorinated regions and aromatic regions, while lF-MWCNTs are inclined to be a homogeneous structure on the basis of their dispersion behavior. According to dispersion theory based on surface energy and Hansen solubility parameters (HSPs), it was indicated that the corresponding preferable solvents are different for different regions. As a result, good solvents of hF-MWCNTs are distributed in a quite wide scope while lF-MWCNTs can be dispersed only in a significantly narrow range of solvents. The HSPs of lF-MWCNTs and hF-MWCNTs are determined to be δD = 17.6 MPa1/2, δP = 11.8 MPa1/2, δH = 8.8 MPa1/2 and δD = 16.9 MPa1/2, δP = 9.3 MPa1/2, δH = 13.5 MPa1/2, respectively. As a result, mixed solvents of acetone and water were carefully tuned to be compatible with hF-MWCNTs. The dispersion behaviors of lF-MWCNTs and hF-MWCNTs in epoxy were also predicted according to HSPs. It was found that hF-MWCNTs maintain a stable dispersion in epoxy due to their heterogeneous structure at elevated temperatures.

Preparation of Highly Uniform Polyurea Microspheres through Precipitation Polymerization and Their Characterization

Uniform polyurea (PU) microspheres were prepared through precipitation polymerization of isophorone diisocyanate (IPDI) in water–acetone mixed solvent, under mechanical oscillation and quiescent conditions. Higher yield with better uniformity for the microspheres was achieved under the quiescent process. The preparation was therefore optimized for the quiescent process. The maximal IPDI loading reached 11.0 wt % with the yield of the microspheres of 88.5%. With acetone replaced by acetonitrile, this yield was increased further to 93.5% combined with also a higher IPDI loading of 15.0 wt % at the same time. The chemical structure of PU was studied using nuclear magnetic resonance. PU microspheres, insoluble in most of organic solvents tested, were dissolved in m-cresol at 30 °C and in acetic acid at 66 °C. These results showed that the PU microspheres consisted of only linear polymers. This work provides therefore a simple and promising protocol for large-scale production of highly uniform polymer microsph...

Synthesis, growth, optical and anisotropic mechanical behaviour of organic nonlinear optical imidazolium 2-chloro-4-nitrobenzoate single crystals

The title compound, imidazolium 2-chloro-4-nitrobenzoate (I2C4NB), has been synthesized and optical quality single crystals were grown with a dimension of \(4 \times 2 \times 1\) mm3 using an ethanol and acetone (1:1) mixed solvent by slow evaporation solution growth technique. The powder XRD analysis confirmed the crystal structure and found that it is crystallized in the non-centrosymmetric space group P21 with the monoclinic system. The symmetries of molecular vibrations were confirmed by FT-IR spectrum. The CHN(S) analysis confirmed the stoichiometric composition of the grown crystal. It also exhibits a good transparency in the entire visible region (300-800nm) and it was thermally stable up to 131.1 °C. The microhardness measurement shows the anisotropic nature of I2C4NB and also that it belongs to a soft material category. Photoconductivity studies reveal a linear increase of the photocurrent with respect to the applied electric field. HOMO LUMO studies were carried out for the crystal. The second harmonic generation test by the Kurtz powder method shows that the crystal exhibits phase matching and a conversion efficiency which is 2 times that of KDP.

Morphology Studies of Electrospun Lithium Iron Phosphate (LiFePO<sub>4</sub>)/Cellulose Acetate (CA) Fibers

This work was carried out as a preliminary study of electrospun LiFePO4/CA fibers. Cellulose acetate (CA) and LiFePO4 solutions were prepared separately using mixed solvent of acetone and water, prior to the electrospinning process. Then, electrospinning parameters including solution concentration, distance tip to collector, pump rate, and needle diameter size were optimized. Brunauer Emmett Teller (BET) was used to determine the surface area of CA fibers. Viscosity of CA solution was obtained by viscometer. LiFePO4/CA fibers were stabilized and carbonized at different temperature. The surface morphology and microstructure of the obtained LiFePO4/ CA fibers were then characterized using scanning electron microscope (SEM). In this work, it is shown that different electrospinning parameter, solution concentration and solution viscosity gives different fibers diameter and distribution. Moreover, the stabilization and carbonization temperature of LiFePO4/CA fibers may also affect the fibers microstructure.

Extractions and Purification of Nuciferine from Lotus Leaves

Four kinds of extraction methods such as Acid-Ethanol Extraction (AEE), Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE) and Enzyme-Assisted Extraction (EAE) were used to extract Nuciferine from lotus leaves. The crude Nuciferine was further purified by re-crystallization. Results showed that compared with AEE, MAE and EAE, UAE exhibited highest extraction ratio (97.05%) with the irradiation power of 400 W at 50°C for 30 min, which indicates UAE is an efficient, rapid and simple Nuciferine extraction technique. The mixed solvent of acetone, petroleum ether, methanol and acetonitrile rather than single solvent was shown to be the most effective for re-crystallization of Nuciferine while stirring (600 rpm) at a storage temperature of 10°C for 24 h, resulting in higher purity (96.85%) and yield (94.7%). The purity of Nuciferine was increased from an average of 53.19% of the crude product to an average of 96.85% of purified product that were detected by the HPLC analysis. So, UAF combined with re-crystallization can be applied to extraction and purification of Nuciferine to improve its industrial mass production and increase greatly economic additional value.

A modified sol–gel method using acetone–ethanol mixed solvent for fast constructing nanometric TiO2 shells

We successfully constructed uniform and complete TiO2 shells on SiO2 cores in a short reaction time (2h) and obtained the core–shell particles with high dispersibility. In this modified sol–gel method, the adopting of ethanol–acetone mixed solvent was critical and advantageous for the fast formation of TiO2 shells. When acetone was controlled at an optimum fraction in solvent (acetone:ethanol=1.2:1v/v), it not only increased the hydrolysis rate of precursor (i.e., titanium (IV) tetrabutoxide) and the condensation rate of titanium oligomers, but also regulated these two sub-reactions of TiO2 formation to be in balance – and thus suppressed the occurrence of agglomeration during TiO2 coating. In addition, the influence of the concentration of catalyst NH3 and precursor titanium (IV) tetrabutoxide was also investigated. Furthermore, the thickness of TiO2 shells on 366nm SiO2 cores was varied from 30 to 107nm by simply adjust the addition volume of precursor, as the regulation role of acetone was widely applicable for different concentration of precursor. Finally, the obtained TiO2 shells were proved to be able to crystallize to anatase shells by calcination, while the core–shell structure showed high stability at high temperature.

Isolation and Identification of Two Novel Condensed Aromatic Lactones from Zhundong Subbituminous Coal

Zhundong subbituminous coal was extracted with isometric carbon disulfide (CDS) and acetone mixed solvent (IMCDSAMS) to obtain the extract (EM). EM was fractionated with petroleum ether (PE), CDS, methanol, acetone, IMCDSAMS, and tetrahydrofuran to obtain the sub-extracts 1–6 (ES1–ES6), respectively. ES2 was sequentially eluted with PE and 30, 50, and 70% CDS/PE mixed solvents through a silica-gel-packed column to obtain eluted fractions 1–4 (EF1–EF4). A series of condensed aromatic lactones (CALs) were detected in EF4. Among them, 5H-phenanthro[1,10,9-cde]chromen-5-one and 4H-benzo[5,10]anthra[1,9,8-cdef]chromen-4-one were further isolated as nearly pure compounds by gelatin column chromatography and identified by gas chromatography/mass spectrometry, atmospheric solid analysis probe/time-of-flight mass spectrometry, Fourier transform infrared spectrometry, 1H nuclear magnetic resonance spectrometry, and 1H–1H correlation spectrometry. Main fragmental ions in the mass spectrum of each CAL are formed by successive losses of m/z 28 (CO) and 29 (−CHO) from the molecular ion. An effective way to isolate CALs from low-rank coals was provided in this paper.

Preparation and characterization of electrospun poly(vinylidene fluoride)/poly(methyl methacrylate) membrane

In this work, nanofibrous poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) membranes with different PMMA contents from 10 wt% to 20 wt% were prepared by electrospinning. The morphology of resultant membranes was investigated using scanning electron microscopy. It was found that the morphology of PVDF/PMMA electrospun nanofibers in the membrane was highly dependent on the solvent used during the electrospinning process. PVDF/PMMA nanofibers with beads were formed in the electrospun membrane when N, N-dimethylformamide (DMF) solvent was used due to its low evaporation rate. Uniform PVDF/PMMA nanofibers without beads in the electrospun membranes were obtained by DMF–acetone mixed solvent. The crystallization behavior of PVDF in the electrospun PVDF/PMMA membranes was investigated using differential scanning calorimetry and Fourier transform infrared spectroscopy. The β form crystalline structure was the major crystalline phase of PVDF in electrospun PVDF/PMMA membranes, and PMMA may suppress the formation of α crystalline phase of PVDF. The crystallinity degree of PVDF in the electrospun PVDF/PMMA membranes was lower than that of the electrospun PVDF membrane, and the annealing could effectively improve the crystallinity degree of PVDF in electrospun membranes. Moreover, it was found that the annealing has no adverse effect on the low density, high porosity, and water vapor permeability of electrospun membranes.