FLUID PHASE EQUILIBRIA
·
2019
·
IF 2.514
Ying Zhang,Qi Zhou,Taotao Zhan,Junshuai Chen,Maogang He
n -Pentane is one of the main components in many industrial fluids, and is widely used as the fuel. The speed of sound can be used for developing the Helmholtz energy formulation and calculating other thermodynamic properties, which has not been reported yet for supercritical n -pentane. In this paper, the speed of sound in supercritical n -pentane was measured by the Brillouin light scattering (BLS) technique within the temperature limits of (422.69–653.53) K along four isobars at p = (3.5, 6.0, 8.0, and 10.0) MPa. The relative uncertainty of our BLS experimental system is estimated to be less than 0.6% and the relative uncertainty of the reported speed of sound values is estimated to be 0.85% considering the influence of impurities in the sample. The dependences of the speed of sound on temperature and pressure were also analyzed. At the end, we compared the experimental data with the calculated values from the multiparameter EOS proposed by Span and Wagner and the Modified BWR EOS proposed by J. Ratanapisit and J.F. Ely. The AARD is 1.3% for the multiparameter EOS and 1.5% for the Modified BWR EOS, respectively.
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Lele Jin,Wenzhi Li,Qiying Liu,Longlong Ma,Chao Hu,Ajibola T. Ogunbiyi,Mingwei Wu,Qi Zhang
In this study, the Mo-promoted Ir/SiO 2 (Ir-MoO x /SiO 2 ) catalysts combined with the zeolite HZSM-5 were used for the direct conversion of microcrystalline cellulose (MCC) to liquid fuel (C 5 /C 6 alkanes) in n-dodecane/H 2 O system. A synergistic effect was formed between the partially reduced MoO x species and the Ir particles, which effectively promoted the catalytic activity of Ir/SiO 2 catalyst. When the Mo/Ir molar ratio was 0.5, a high yield of C 5 /C 6 alkanes (91.7%) was achieved at 210 ℃ for 12 h. In addition, the main component of C 5 /C 6 alkanes was n-hexane, which was proven to be obtained by the hydrogenolysis of the key intermediate, sorbitol, formed from the hydrolysis and hydrogenation of MCC.
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ELECTROPHORESIS
·
2019
·
IF 2.754
Yuan-Yuan Cui,Huan Yao,Cheng-Xiong Yang,Xiu-Ping Yan
Microporous organic networks (MONs) are a new class of porous materials synthesized via Sonogashira coupling reactions between organic building blocks. Here we report an in situ synthesis approach to fabricate MONs coated capillary column for high resolution GC separation of hydrocarbons. The McReynolds constant evaluation reveals the MONs coated capillary is a non-polar column. The MONs coated capillary column shows good resolution for GC separation of diverse important industrial hydrocarbons such as linear and branched alkanes, alkylbenzenes, pinene isomers, ethylbenzene and styrene, cyclohexane and benzene. The MONs coated capillary column gave a high column efficiency of 1542 plates per meter for hexane and good precision for replicate separations of the selected hydrocarbons with the RSDs of 0.2–0.3, 1.5–3.1, and 1.9–3.3% for retention time, peak height and peak area, respectively. The MONs coated capillary also offered better resolution than commercial Inert Cap-1 and Inert Cap-5 capillary columns for hexane and heptane isomers. These results reveal the potential of MONs as novel stationary phases in GC.
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FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Lele Jin,Wenzhi Li,Qiying Liu,Longlong Ma,Song Li,Yang Liu,Baikai Zhang,Qi Zhang
The liquid fuel (made of C 5 /C 6 alkanes) was obtained directly from the hydrogenolysis of microcrystalline cellulose (MCC) with Ir-VO x /SiO 2 combined with HZSM-5 as the composite catalyst in a biphasic system (n-dodecane + H 2 O). The performance of the catalyst was investigated by carrying out a series of experiments using various V/Ir molar ratios , catalyst dosages, reaction temperatures, reaction time, hydrogen pressure and substrates. At the optimized conditions, the cellulose was almost completely converted, and at the same time, a high C 5 /C 6 yield of 85.1% was obtained at 210 °C for 24 h and 6 MPa with the V/Ir molar ratio being 0.13. These results not only proved that Ir-VO x /SiO 2 (V/Ir = 0.13) has excellent performance for the hydrogenolysis of MCC to liquid alkanes, but also indicated that vanadium is a good metal promoter for iridium . In addition, it was proven the C5/C6 alkanes were obtained via sorbitol through the combined effect of Ir-VO x /SiO 2 and HZSM-5.
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CELLULOSE
·
2019
·Vol. 26
·期 6
·3801-3814
·
IF 3.917
Liu Jing,Hu Huichao,Gong Zhenggang,Yang Guangxu,Li Runqing,Chen Lihui,Huang Liulian,Luo Xiaolin
Abstract Based on Hildebrand solubility parameter (δ H ) theory, a novel organosolv pretreatment medium (OPM), 1-pentanol (80%, v/v)–water mixture with a δ H value of 27.4 (J/cm 3 ) −1/2 , was discovered. This OPM achieved near-complete removal of non-cellulosic components (hemicellulose 96.2% and lignin 87.8%) from bamboo under mild conditions [130 °C, 20 min, 4% (w/w) H 2 SO 4 ]. For the OPMs with similar δ H values [DMSO (80%, v/v)- and 1-pentanol (80%, v/v)-water, 30.9 vs. 27.4 (J/cm 3 ) −1/2 ] to that of bamboo lignin [28.3 (J/cm 3 ) −1/2 ] used in this study, the effect of the δ h value (contribution of hydrogen-binding force to the δ H ) on lignin removal was also discussed. After overcoming the negative effect of lignin deposits on enzymes with biocompatible soy protein (SP), a decent cellulose enzymatic conversion (EC) of 92.6% was achieved by 1-pentanol (80%, v/v)-water induced organosolv pretreatment at a low cellulase loading (5 FPU/g glucan). This cellulose EC was much higher than those of other OPMs (< 63%) with the δ H values very different from that of bamboo lignin. Integration of organosolv pretreatment with an ideal OPM and enzymatic hydrolysis using SP as an additive can be thereby viewed as a viable way to achieve the robust cellulose EC at low enzyme loading, which shows great potential for improving the economics of organosolv pretreatment-based lignocellulose biorefinery. Graphical abstract
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Materials Research Express
·
2019
·Vol. 6
·期 11
·1150c2
·
IF 1.449
Ming Li,Ting Wang,Jia Zhang
Lightweight porous polyurea-modified silica aerogels have been synthesized through an ambient pressure drying technique. The silica wet gels were prepared by copolymerization and gelation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxylsilane (APTES) during which amine functional groups were introduced into the skeletal framework. The amine sites then became anchors for cross-linking the silica particles of preformed skeleton by attachment of hexamethylene diisocyanate (HDI), resulting in a conformal polyurea coating on the surface of silica aerogels. The effects of APTES/TEOS volume ratio and HDI concentrations on the evolution of microstructure and pore characteristics of silica aerogels were investigated in detail. The various APTES/TEOS volume ratio did not resulted in a significant change of the density, while pores size in the network structure became larger when the APTES/TEOS volume ratio increased from 10% to 30%. The amount of polyurea cross-linked into the aerogels appeared to vary regularly with the increase of HDI concentration from 0 to 20%. More polyurea was attained when silica wet gels were immersed into the solution of a larger HDI concentration, which rendered the interparticle neck region of silica aerogels wider. The resulting conformal coatings of polyurea reinforced the inorganic silica networks while inevitably occupied some voids at the same time. The investigation provides data for the synthesis of tailor made polyurea-modified silica aerogels under ambient pressure drying method.
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MOLECULES
·
2019
·Vol. 24
·期 23
·4275
·
IF 3.06
Qian-Chun Zhang,Wu-Li Yan,Li Jiang,Yu-Guo Zheng,Jing-Xin Wang,Run-Kun Zhang
In this work, we successfully developed a novel and sensitive gas sensor for the determination of trace acetophenone based on its cataluminescence (CTL) emission on the surface of nano-praseodymium oxide (nano-Pr6O11). The effects of working conditions such as temperature, flow rate, and detecting wavelength on the CTL sensing were investigated in detail. Under the optimized conditions, the sensor exhibited linear response to the acetophenone in the range of 15–280 mg/m3(2.8–52 ppm), with a correlation coefficient (R2) of 0.9968 and a limit of detection (S/N = 3) of 4 mg/m3(0.7 ppm). The selectivity of the sensor was also investigated, no or weak response to other compounds, such as alcohols (methanol, ethanol,n-propanol,iso-propanol,n-butanol), aldehyde (formaldehyde and acetaldehyde), benzenes (toluene,o-xylene,m-xylene,p-xylene),n-pentane, ethyl acetate, ammonia, carbon monoxide, carbon dioxide. Finally, the present sensor was applied to the determination of acetophenone in human exhaled breath samples. The results showed that the sensor has promising application in clinical breath analysis.Keywords:cataluminescence;sensor;acetophenone;Pr6O11
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ANALYTICA CHIMICA ACTA
·
2018
·
IF 5.123
Mingxia Liu,Hong Zhao,Zhiguo Zhang,Xiangjun Li,Lanqun Mao,Ruiping Zhang,Yuekui Wang
A new analytical method based on capillary zone electrophoresis-mass spectrometry (CZE-MS) was proposed and validated for the simultaneous determination of four stereoisomers of 3-hydroxyaspartate with two chiral centers in rat cerebrospinal fluid (CSF) in absence of optically pure single enantiomer standards. The derivatization reagent 9-fluorenylmethyl chloroformate (FMOC-Cl) was found to assist chiral separation and the derivatized enantiomers of 3-hydroxyaspartate can achieve enantioseparation with a lower concentration (6 mM) of β-cyclodextrin (β-CD), while underivatized 3-hydroxyaspartate cannot be separated. The enhanced interactions between derivatized analytes and β-CD were demonstrated by proton nuclear magnetic resonance ( 1 H NMR). The four stereoisomers of FMOC-3-hydroxyaspartate were identified successfully using a new method based on experimental and calculated electronic circular dichroism (ECD) spectra combined with the comparison of CE peak areas. Large volume sample stacking with polarity switching (LVSS-PS) was used to increase sensitivity and the detection limit of 356 nM was achieved for L-THA, which was around 10-fold improvement compared to the normal CE-MS analysis. The composition of the background electrolyte (BGE) was optimized by response surface methodology (RSM). Under the optimal conditions, satisfactory results of L-THA were obtained in terms of linearity over the range of 2–80 μM (R 2 > 0.99) and precision (RSD below 1.43% and 2.56% for migration time and peak area, respectively). The recoveries for all four stereoisomers in spiked rat CSF ranged from 91.2% to 99.5%. The method has been successfully applied to rat CSF analysis and D- erythro -3-hydroxyaspartate (D-EHA) was detected.
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THERMOCHIMICA ACTA
·
2018
·
IF 2.189
Song Feng,Qincheng Bi,Hui Pan,Zhaohui Liu
A flow calorimeter based on energy conservation was constructed for experimental measurements of isobaric specific heat capacity. The relative expanded uncertainty of isobaric specific heat capacity was identified as 2.32% (coverage factor k = 2). In the peak region, the relative expanded uncertainty of isobaric specific heat capacity increased to 7.10% (coverage factor k = 2). To verify the accuracy and reliability of the flow calorimeter, pure water and different mole-fraction binary mixtures of n -pentane and acetone were tested in the liquid and vapor phases. The maximum absolute deviation and average absolute deviation were 1.42% and 0.51%, respectively. The isobaric specific heat capacity of emulsified kerosene with different mass fractions was measured at temperatures ranging from 301 K to 878 K and at pressure p = 3 MPa. The effects of different mass frictions of water and temperature on the isobaric specific heat capacities were analyzed in detail. Finally, the isobaric specific heat capacity of RP-3 was compared with that of emulsified kerosene.
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FUEL
·
2018
·
IF 4.908
Yao Zhong,Qiang Deng,Peixin Zhang,Jun Wang,Rong Wang,Zheling Zeng,Shuguang Deng
Sulfonic acid functional strong acidic catalysts are largely used in various chemical reactions. However, in many reactions with water as product, the catalytic activity and selectivity are unsatisfactory, because hydrophilic acid sites of SO 3 H would suffer from acidity decreasing and some hydrolysis side reactions would occur via water adsorption. Herein, a novel hydrophobic arenesulfonic acid functionalized biochar was successfully prepared for the first time by one-pot diazo reduction method of biochar with amino-arenesulfonic acid (such as, 4-aminbenzenesulfonic acid, 4-amino-1-naphthalenesulfonic acid, 8-amino-1-naphthalenesulfonic acid, 4-amino-3-hydroxy-1-naphthalenesulphonic acid). It has a large specific surface area of 200–400 m 2 /g, a hydrophobic network with water contact angle higher than 120° and a higher concentration of sulfonic acid over 1.0 mmol/g. Moreover, the hydrophobicity-oleophilicity and acidity are increased with the arene length and grafting amount of arenesulfonic acid. In the esterification reaction of fatty acid with methanol as well as the transesterification reaction of glycerol trioleate with methanol for the production of biodiesel, the sulfonated biochar shows a higher conversion of 96.7% for esterification and 86.3% for transesterification compared with amberlyst-15 (86.7%, 39.9%) and traditional sulfonation biochar-SO 3 H (27.4%, 32.6%). In the alkylation reaction of 2-methylfuran with cyclopentanone for the production of high-density biofuel, its catalytic efficiency with target product yield of 76.1% is higher than that of amberlyst-15 (50.2%) and traditional sulfonation biochar-SO 3 H (13.2%), because of its hydrophobicity and strong acidity. Furthermore, the catalyst is stable and shows an excellent cycle performance after 6 runs. The successful preparation of hydrophobic biochar-based acidic catalysts not only provides a new way for high-value utilization of biochar, but also eliminates the negative effect of water on many catalytic reactions.
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-6
·
IF 5.578
Yao Feng,Yi Bin,Shen Caihong,Tao Fei,Liu Yumin,Lin Zhixin,Xu Ping
Luzhoulaojiao liquor is a type of Chinese liquor that dates back hundreds of years, but whose precise chemical composition remains unknown. This paper describes the screening of the liquor and the identification of its compounds using comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC/TOF-MS). Samples were prepared by both liquid-liquid extraction and solid-phase microextraction, which facilitated the detection of thousands of compounds in the liquor, thus demonstrating the superior performance of the proposed method over those reported in previous studies. A total of 320 compounds were common to all 18 types of Luzhoulaojiao liquor studied here and 13 abundant and potentially bioactive compounds were further quantified. The results indicated that the high-performance method presented here is well suited for the detection and identification of compounds in liquors. This study also contributes to enriching our knowledge of the contents of Chinese liquors.
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Polymer Chemistry
·
2015
·Vol. 6
·期 18
·3529-3536
·
IF 5.52
Feng Chen,Xiaoping Jiang,Tairong Kuang,Lingqian Chang,Dajiong Fu,Jintao Yang,Ping Fan,Mingqiang Zhong
Mesoporous silica nanoparticles have been widely adopted in energy, biology and medicine due to their well-ordered and stable structures. Nevertheless, few attempts have been made to study these materials as a sensing tool. Herein, we report a “smart” sensor for the dual-detection of the pH value and temperature, which was implemented with environmentally responsive polyelectrolyte/mesoporous silica electrodes. Using SBA-15 silica as the framework, we functionalized the internal mesopores with DMAMEA monomer via surface-initiated RAFT polymerization (“grafting-from” method). By controlling the degree of polymerization, the pore size and the specific surface area can be precisely controlled. When the degree of polymerization was optimized to 75, the hybrid material showed significant sensitivity in response to the pH value in the range of 4–10 and optimally responded to the temperature at 39 °C, setting a pH value of 10. The ionic conductivities of the template Fe(CN)64−/3− and Ru(NH3)62+/3+ ions were switchable in different conditions. These results suggest that the polyelectrolyte/mesoporous silica hybrid materials could have potential for application in dual-functional sensors in environmental detection.
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危险品化学品经营许可证（带存储）