CATALYSIS SURVEYS FROM ASIA
·
2018
·Vol. 22
·期 4
·222-229
·
IF 3.081
Gao Meixiang,Jiang Haoxi,Zhang Minhua
Series of ZrO 2 supported on the different kinds of SiO 2 carriers were applied in the reaction of 1, 3-butadiene formation from ethanol and acetaldehyde. ZrO 2 /Nano-SiO 2 performed the best performance with the 1, 3-butadiene selectivity 91.43% and the total conversation 52.39%. Prepared catalysts were characterized by N 2 adsorption–desorption, TEM, XRD, temperature-programmed desorption of NH 3 and CO 2 , FTIR spectroscopy of adsorbed pyridine and CO 2 , Raman XPS. The results show that the weak Lewis acid and basic sites are appropriate for BD formation. Furthermore, more and balance acid-basic sites are rather important for the reaction of ethanol and acetaldehyde conversion to BD.
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CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
H.Z. Li,W.Z. Li,Y.J. Yang,H.L. Tai,X.S. Du,R.Y. Gao,S.Y. Li
Pyroelectric properties of 1–3 ceramic/polyvinylidene fluoride (PVDF) composites by using barium titanate nanowires (BTnws) and dopamine modified BTnws (DM-BTnws) as inclusions were firstly reported. 0–3 composites based on dopamine modified BT nanoparticles (DM-BTnps)/PVDF were also prepared for comparison. It was found that low contents of DM-BTnws in PVDF are beneficial for achieving high fraction of β-phase content based on the analysis results of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electric displacement-electric field ( D-E ) measurements. The enhancement of β-phase content in the DM-BTnws/composited film was believed to originate from strong hydrogen bonds interactions between poly-dopamine and PVDF molecules, which induced phase transition in PVDF from α-phase into β-phase. However, although DM-BTnws improved β-phase content and, accordingly, pyroelectric coefficient of the composites, they deteriorated dielectric performances of PVDF, reducing pyroelectric performances of the composites in terms of voltage and detectivity figures of merit.
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JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Jianlin Peng,Meiling Qi
This work describes the investigation of utilizing a chain-typed thiophene-based π-conjugated polymer, i . e ., poly(3-hexylthiophene) (P3HT), as the stationary phase for gas chromatography (GC). The P3HT column was statically prepared and investigated for its column efficiency, polarity, separation performance, repeatability and thermal stability. As a result, it showed moderate polarity and column efficiencies of 3260, 3310 and 3790 plates/m for 1-octanol, naphthalene and n -dodecane, respectively. As evidenced, it exhibited high-resolution performance for aliphatic and aromatic isomers, including those critical pairs such as phenanthrene/anthracene and p -/ m -benzenediol isomers. Moreover, it displayed stronger retention for alkanes, alcohols and phenols in comparison to the polysiloxane stationary phase with close polarity. Also, the P3HT column had good repeatability and reproducibility with the RSD values less than 0.05% for run-to-run, 0.17–0.54% for day-to-day and 2.7–5.2% for column-to-column, and good thermal stability up to 260 °C. This work demonstrates the promising future of the thiophene-based polymer and its derivatives in separation science.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2018
·
IF 1.454
Dongfang Liu,Youlin Ma,Jiang Tan,Lu Wang,Quanwu Tang,Hongsheng Lu
We reported that the phase conversion of the micelles in aqueous solution prepared by sodium oleate (NaOA) and 3-(diethylamino)-propylamine (DEAPA) in the presence of carbon dioxide. This micellar structure is very sensitive to CO2 and the pH value of the solution is continuously reduced with the continuous introduction of carbon dioxide. When pH > 10.2, the mixed solution of NaOA and DEAPA is mainly in the form of spherical micelles; when the 10.2 > pH > 9.6, the mixed solution mainly in the worm-like micelles (WLM), where the solution has a significant viscosity change; when the 9.6 > pH > 9.1, the NaOA and DEAPA mixed solution becomes the aqueous two-phase system (ATPS), which is composed of two layers, the upper layer is the vesicle structure and the lower layer is the WLM structure; when the pH between 9.1 > pH > 9.0, NaOA and DEAPA mixed solution form vesicles, thus realizing the regulation of CO2 on the micellar structure transition of NaOA and DEAPA mixed solution. Such these microstructures transition could be confirmed by Rheology measurement, DLS and Cryo-TEM.
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Soft Matter
·
2018
·Vol. 14
·期 21
·4231-4237
·
IF 3.709
Dahua Li,Yuzhi Xing,Lan Ding,Chengfeng Wu,Guangliang Hou,Bo Song
3-Hydroxyflavone derivatives have great potential as fluorescent probes for bio-labeling in aqueous medium. They were extensively studied in various organic solvents for the “excited state intramolecular proton transfer” process, but seldom addressed in aqueous solution due to the poor water solubility. Herein, an amphiphilic molecule bearing 3-hydroxyflavone and oligo(ethylene oxide) (denoted as 3HF-EO) was designed and synthesized. Different from the fluorescence in organic solvents, 3HF-EO in aqueous solution showed a remarkable single fluorescence emission, which is ascribed to the fluorescence of its anionic species. We found that the fluorescence intensity could be efficiently tuned via host–guest complexation. α-CD has little effect on the emission, while β-CD and γ-CD lead to enhanced and reduced emissions of 3HF-EO, respectively. The 1H NMR and 2D NOESY NMR spectra indicate that α-CD barely had any interaction with 3HF-EO, while β-CD and γ-CD formed complexes with one and two 3HF-EO molecules, respectively. These results provide a sound explanation for the modulated fluorescence intensity.
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TRANSACTIONS OF TIANJIN UNIVERSITY
·
2012
·Vol. 18
·期 5
·315-319
·
IF 0
Feng Yakai,Chen Chengbin,Zhang Li,Tian Hong,Yuan Wenjie
A series of novel copolymers were successfully synthesized by ring-opening polymerization (ROP) of 3(S)-methyl-morpholine-2,5-dione (MMD) and 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (MBC) using stannous octoate as catalyst. The copolymers were characterized by means of 1H-NMR and FT-IR spectroscopy. Gel permeation chromatography (GPC) test shows that the average-number relative molecular mass and average-weight relative molecular mass slightly increase with the increase of MBC content in feed. The results of differential scanning calorimetry (DSC) demonstrate that the glass transition temperature of copolymers increases with the increase of MBC content in copolymers. The copolymers of MMD and MBC are amorphous copolymers, as indicated by DSC results, while the homopolymer of MMD is semicrystalline.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2015
·
IF 2.587
Jinxia Zhou,Tingyu Huang,Yuling Zhao,Zhi Xia,Zhanwei Xu,Songyan Jia,Jianji Wang,Z. Conrad Zhang
Ionic liquids have been widely studied as effective reaction media for the conversion of glucose or cellulose to 5-hydroxymethhylfurfural (5-HMF). However, the recovery of 5-HMF from ionic liquids, typically carried out by extraction, has been encountered with very low extraction efficiency, which limited the reusability of the solvents. Through this work, based on the model biphasic system that consists of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) as the ionic liquid phase and methyl isobutyl ketone (MIBK) as the extractant phase, the dominant force that suppresses the extraction efficiency of 5-HMF was identified as being the strong hydrogen bonding between 5-HMF and [BMIM]Cl. Solvent mediation with functional promoters have been established as a new strategy to shift this force, resulting in improved extraction efficiency of 5-HMF from the ionic liquid. For example, with ethanol as a promoter, the distribution coefficient of 5-HMF was about 10 times higher than that without a promoter.
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BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Jingyun Wang,Mingdong Zhou,Yuguo Yuan,Quan Zhang,Xiangchen Fang,Shuliang Zang
Quaternary ammonium perrhenates were applied as catalyst to promote the hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The quaternary ammonium perrhenates displayed good catalytic performance for cellulose hydrolysis. Water was also proven to be effective to promote cellulose hydrolysis. Accordingly, 97% of total reduced sugar (TRS) and 42% of glucose yields could be obtained under the condition of using 5 mol% of tetramethyl ammonium perrhenate as catalyst, 70 μL of water, ca. 0.6 mmol of microcrystalline cellulose (MCC) and 2.0 g of [Amim]Cl as solvent under microwave irradiation for 30 min at 150 °C (optimal conditions). The influence of quaternary ammonium cation on the efficiency of cellulose hydrolysis was examined based on different cation structures of perrhenates. The mechanism on perrhenate catalyzed cellulose hydrolysis is also discussed, whereas hydrogen bonding between ReO 4 anion and hydroxyl groups of cellulose is assumed to be the key step for depolymerization of cellulose.
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RSC Advances
·
2015
·Vol. 5
·期 22
·16684-16690
·
IF 3.84
Ting Wu,Luyan Wang,Yue Zhang,Sen Du,Wenjuan Guo,Meishan Pei
Poly(3-thiophene acetic acid) (PTAA) nanowires are synthesized in a high yield by electrochemical polymerization, with diameters of about 200 nm and lengths of tens of micrometres. In the reaction systems, the water soluble macromolecules hydroxyethylcellulose (HEC), chitosan (Cs) and polyacrylamide (PAM) are added respectively as templates through a dip-coating process, where the macromolecules are spread on an indium tin oxide glass which is used as the working electrode. However, when polyethylene glycol (PEG) is used, only a PTAA film can be obtained. Therefore the interactions between template macromolecules and TAA monomers play a key role in the formation of PTAA nanowires and the dip-coating process presents an effective way to produce 1D conductive polymer materials with controllable shape. The optical, electrochemical and surface properties are also studied respectively to compare the performances of PTAA film and nanowires, where the latter indicates good electrochemical responsiveness and evidently increased hydrophobicity.
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Chemistry Central Journal
·
2013
·Vol. 7
·期 1
·1-5
·
IF 1.312
Liu Run-Qiang,Bai Lian-yang,Zhang Yi-Jun,Zhang Yu-Ping
Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far.Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization.Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl.
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RSC Advances
·
2015
·Vol. 5
·期 41
·32416-32420
·
IF 3.84
Kang Qin,Kai Wang,Yang Li,Fanhe Kong,Tao Wang
The phase behavior of the 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]) and carbon dioxide (CO2) system from atmospheric to supercritical state was investigated at 0.1–15.0 MPa and 308.15–343.15 K. The solubility data of CO2 in [emim][BF4] and the volumetric expansion ratios of CO2-saturated [emim][BF4] were provided. Experimental results indicated that although CO2 dissolved significantly in [emim][BF4] (from 0 to 62 mol%), the ionic liquid phase only had an expansion ratio less than 17 vol%. The density difference between CO2-saturated [emim][BF4] and pure [emim][BF4] was obvious at high pressure and low temperature, with a maximum of 16.11% at 308.15 K and 15.0 MPa. Based on the experimental results, a fitting equation applicable to precise data interpolation was proposed for the CO2-saturated [emim][BF4] density in this study.
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NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 13
·5429-5435
·
IF 3.269
Yongyun Mao,Qian Zhao,Tingting Pan,Jiayan Shi,Shimei Jiang,Meiwan Chen,Bingpu Zhou,Yanqing Tian
Integrating an oxygen-sensitive probe (OSP) onto a three-dimensional (3D) microstructure substrate is a plausible technique to significantly improve the sensitivity of oxygen sensors. Despite the fact that polydimethylsiloxane (PDMS) matrices are regarded as the ideal sensory support, there are still no reports on an OSP functionalized flexible PDMS-based micropillar array (PDMS-MPAs) film as an optical oxygen sensor with capabilities to efficiently improve the sensor's overall performance, e.g. sensitivity, detection limit and stability against photo-bleaching. Herein, we reported the covalent bonding of a functional copolymer of platinum porphyrin (PtTPP)/3-(trimethoxysily)propylmethacrylate (PtTPP/TPMA) as the OSP on the surface of hydroxyl-modified PDMS-MPAs through a “grafting reaction” between PtTPP/TPMA and PDMS-MPAs. The homogeneous dispersion and well-isolated arrangement of the PtTPP/TPMA OSP on the 3D PDMS-MPA surface can ensure that the grafted OSP efficiently quenches the oxygen molecules. Consequently, the 3D PtTPP/TPMA-PDMS-MPA sensor film gives rise to a high fluorescence quenching efficiency of about 95% at 1 atm O2 (I0/I100 = 23) and 96% in aqueous solution (I0/IO2satu = 16) with an excellent linear Stern–Volmer plot (ksv = 0.1 h Pa−1, R2 = 0.997 in gas atmosphere and ksv = 12.8 mmol−1 L, R2 = 0.999 in aqueous solution, respectively), excellent reversibility and an ultra-low detection limit (4.7 μmol L−1) when compared with state-of-the-art PDMS-based oxygen sensors. Apart from the competitive sensitivity, the highly durable, reusable superiorities of the 3D PtTPP/TPMA-PDMS-MPA film can further facilitate the exploration and realization of the presented strategy for future oxygen sensor applications, such as the characterization of nearly anoxic systems in harsh environments.
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