查找使用阿拉丁产品的科研文献

Isobaric Vapor-Liquid Equilibria in 2-Methylthiophene–Cycloalkane Mixtures at 90.00 kPa

Xu Zhigang,Junqiang Wang,Wei Zhao,Xiaoliang Li

Abstract New isobaric vapor-liquid equilibrium data for the binary mixtures of methylcyclopentane + 2‑methylthiophene, cyclohexane + 2-methylthiophene, methylcyclohexane + 2-methylthiophene and ethylcyclohexane + 2-methylthiophene systems were determined by a modified Rose-Williams equilibrium still under the pressure of 90.00 kPa. All the vapor-liquid equilibrium data measurements passed the thermodynamic consistent test by using the Herington method and the Van Ness test, respectively. No azeotropic behavior was observed in the tested four binary systems. Meanwhile, the experimental data were correlated by the Wilson activity coefficient model and also compared with the original UNIFAC and UNIFAC Dortmund predictive models. All results demonstrated that the original UNIFAC model gave better predictions than the UNIFAC Dortmund model.

Isobaric (Vapor + Liquid) Equilibria for 2-Methylthiophene with 1-Octene, Cyclohexene, 2,3-Dimethyl-1-butene, and 2,3-Dimethyl-2-butene at 90.00 kPa

Zhe Wang,Li Junzhi,Zhao Wei,Li Xiao Liang

The isobaric vapor-liquid equilibrium data for the four systems consisting of 1-octene + 2-methyl-thiophene, cyclohexene + 2-methylthiophene, 2,3-dimethyl-1-butene + 2-methylthiophene, and 2,3-dimethyl-2-butene + 2-methylthiophene were determined by using a modified Rose-Williams equilibrium still at 90.00 kPa. All the vapor-liquid equilibrium data measurements passed the thermodynamic consistent test by employing the Herington method. The azeotropic behavior was observed in the 1-octene + 2-methyl-thiophene system. Additionally, the experimental data were correlated by the Wilson model, and they were also compared with the original UNIFAC and UNIFAC Dortmund predictive models. All the results indicated that the measured data were in good agreement with the calculated values obtained from the Wilson. Meanwhile, the UNIFAC Dortmund model can provide better prediction result than the original UNIFAC model.

Isobaric (vapor + liquid) equilibria for 2-methylthiophene with n-heptane, 2,2,4-trimethylpentane, n-nonane and n-decane at 90.00 kPa

Junzhi Li,Junqiang Wang,Wei Zhao,Xiaoliang Li

Isobaric vapor-liquid equilibrium (VLE) data for the four systems n -heptane   +   2-methylthiophene, 2,2,4-trimethylpentane   +   2-methylthiophene, n -nonane   +   2-methylthiophene, n -decane   +   2-methylthiophene were measured at 90.00   kPa with a modified Rose-Williams still. Gas chromatography equipped with a flame ionization detector was used to analyze composition of the samples from the vapor-liquid equilibrium systems. All the VLE measurements passed the thermodynamic consistent test using the Herington method and the Van Ness test. The azeotropic behavior was found in the 2,2,4-trimethylpentane   +   2-methylthiophene system. The experimental data were correlated by the Wilson and NRTL activity coefficient models and also compared with the original UNIFAC predictive model. The corresponding parameters for the three models were obtained. The results exhibited that the measured data got agree well with the calculated values using the Wilson, NRTL and original UNIFAC models.

Synthesis and Desulfurization Performance of Functional Silica Gel Modified by Polymeric 1-Vinyl-3-ethylimidazolium Tetrafluoroborate Ionic Liquids

Nan Li,Fang Wang,Zhiqing Zhang,Huihui Nie,Chengcheng Ren,Mei Cui

Polymeric 1-vinyl-3-ethylimidazolium tetrafluoroborate ionic liquids modified microspheres of silica gel were prepared by free radical polymerization in toluene. Characterization with Fourier transform infrared (FTIR), elemental analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and 13C, 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) demonstrated that 1-vinyl-3-ethylimidazolium tetrafluoroborate had successfully loaded on the surface of silica gel and formed a stable polymer coating. Furthermore, to detect the potential desulfurization performance, a series of experiments of model fuel desulfurization with polymeric ionic liquid modified silica gel had been carried out. The desulfurization efficiency of modified silica gel was investigated by removing 2-methylthiophene, benzothiophene, and dibenzothiophene from model fuel (n-heptane/2-methylthiophene, benzothiophene, and dibenzothiophene) under tested conditions. It was shown that the modified silica gel exhibited remarkable desulfurization capacity for aromatic S-containing compounds and the sulfur removal selectivity followed the order of 2-methylthiophene < benzothiophene < dibenzothiophene due to the different density aromatic π-electrons.

Analysis of volatiles from the thermal decomposition of Amadori rearrangement products in the cysteine-glucose Maillard reaction and density functional theory study

Liming Lei,Shang Wang,Ziqian Zhao,Shaohua Dou,Sufang Zhang,Yi Wang,Pengxun Gao,Binchen Wang,Xianbing Xu,Liang Dong

The Amadori rearrangement products are an important flavor precursor in the Maillard reaction. Its thermal decomposition products usually contribute good flavors in foods. Therefore, investigating the thermal breakdown of Amadori products is significant for understanding the flavor forming mechanism in the Maillard reaction. In this study, volatiles from thermal decomposition of Amadori products in cysteine and glucose Maillard reaction was investigated by a thermal desorption cryo-trapping system combined with gas chromatography-mass spectrometry (GC-MS). A total of 60 volatiles were detected and identified. Meanwhile, the forming mechanism of 2-methylthiophene, a major decomposition product, was also investigated by using density functional theory. Seventeen reactions, 12 transition states, energy barrier and rate constant of each reaction were finally obtained. Results reveal that it is more likely for Amadori products of cysteine and glucose to undergo decomposition under neutral or weakly alkaline conditions.

The decomposition and flame retardant mechanism of a tetrazole based P/N/S multi-element compound for epoxy resin

Zi’ang Yu,Gaoyun Qi,Zhenyu Jiang,Zhonglin Luo,Biaobing Wang

In this paper, a P/N/S multi-element flame retardant (TATP) was synthesized by 5-amino-1H-tetrazole, 2-thenaldehyde and DOPO. When TATP content reaches 4 wt%, EP/TATP-4 exhibits 38.1 % of LOI value and UL-94 V-0 rating. Compared to the pure EP, the peak of heat release rate, the total heat release and the total smoke production in cone calorimeter test are dropped by 30.8% and 32.4%, and 51.6% respectively. Moreover, the char residue is dramatically increased by 74.0%. Detailed analysis indicates, the tetrazole group decomposes from TATP firstly, which promotes the cleavage of thiophene ring below 380 o C, much lower than experimentally reported degradation temperature of thiophene compounds. Therefore, besides the emission of enough nonflammable gases, the high-energy density characteristics of the tetrazole ring is also benefited to the thermal decomposition of TATP and make the tetrazole, thiophene and DOPO groups play synergistic impacts on fire safety for epoxy resin. Furthermore, the P/N/S elements are found exerting flame retardant effects both in the gas and condensed phases. The obtained EP/TATP-4 maintains the comparable tensile and flexural properties to pure EP. Remarkably, EP/TATP-4 has high transparency and exhibits excellent UV shielding performance for UVA wavelengths, and has an extraordinarily higher Ultraviolet Protection Factor value of 1983.2.

Visible light photocatalytic oxidative desulfurization using Ti-MCM-41-loaded iron phthalocyanine combined with ionic liquid extraction

Liu Ran,Zhang Juan,Xu Zhice,Zhao Dishun,Sun Shuang

Iron phthalocyanine (PcFe) was loaded on Ti-MCM-41 as visible light photocatalyst (R-PcFe/Ti-MCM-41). Dibenzothiophene (DBT) was photooxidized using R-PcFe/Ti-MCM-41 as a photocatalyst, air as an oxidant, and ionic liquid as the extraction agent during visible light irradiation at room temperature and ambient conditions. The results indicated that photocatalytic efficiency of the amino iron phthalocyanine (NH 2 -PcFe)/Ti-MCM-41 was superior to the other substituent groups. The DBT content in the model oil decreased from 1000 to 44 μg/mL with 95.6% removal rate under the optimal reaction conditions (model oil 10 mL, photocatalyst NH 2 -PcFe/Ti-MCM-41 0.02 g, loading amount of NH 2 -PcFe 0.3 g/g, air flow rate 100 mL/min, reaction time 2 h, room temperature). The kinetics of photocatalytic oxidation of DBT follows first-order kinetics with a rate constant of 1.319 h −1 and halftime of 0.525 h. The photocatalyst NH 2 -PcFe/Ti-MCM-41 was reused for five times, and the catalytic activity decreased slightly. The photocatalytic oxidation system demonstrated significant desulfurization effects on different sulfur compounds and real gasoline, and the sulfur content of the actual gasoline could be reduced from 1000 to 78 ppm.

Alkylation desulfurization of FCC gasoline catalyzed by glycerol-based solid acid catalyst

Jing-jing Li,Xiao-Pu Zhang,Xiao-dong Tang,Miao Zhou,Chun Wang

Extractive desulfurisation of gasoline with tetrabutyl ammonium chloride-based deep eutectic solvents

Chenhua Shu,Tonghua Sun

In this study, three tetrabutyl ammonium chloride (TBAC)-based deep eutectic solvents (DESs) were synthesised and used for desulfurising model and real gasolines. Extraction efficiencies of different DESs followed the order of TBAC/ethylene glycol > TBAC/glycerol > TBAC/malonic acid. After five extraction cycles, the extraction efficiencies of TBAC/ethylene glycol, TBAC/glycerol and TBAC/malonic acid reached 99.5, 99.3 and 99.2%, respectively. Additionally, the structures of original and recycled DESs were analysed and the results showed that DESs maintained their original structures after regeneration. Finally, the desulfurisation performance of DESs for real gasoline was also investigated. This work will provide new green extractants for gasoline desulfurisation.

PEG/PVDF membranes for separating organosulphur compounds from n-heptane: Effect of PEG molecular weight

Wenling Hu,Xiaolong Han,Liangliang Liu,Xin Zhang,Juanqin Xue,Baoyi Wang,Peng Zhang,Xingzhong Cao

Polyethylene glycol (PEG) of three different molecular weights was used to prepare PEG/PVDF composite membranes for separating organosulphur compounds from n -heptane by pervaporation. All the composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and positron annihilation spectroscopy (PAS). The effects of operating temperature, feed sulphur content, and organosulphur species on performance of PEG/PVDF composite membranes with different molecular weights were investigated. When the feed organosulphur was thiophene, the fluxes decreased with an increase in PEG molecular weight, however, the enrichment factors were in a different order: PEG membrane with molecular weight of 35 000 exhibited the highest enrichment factor of 12.59 for thiophene at 85 °C. When the feed organosulphur was 2-methylthiophene or 2,5-dimethylthiophene, it was found that the PEG membrane with molecular weight of 100 000 showed the highest enrichment factor. The results showed that PEG molecular weight has a considerable effect on separation performance for pervaporation desulphurization.

Changes in lipids and aroma compounds in intramuscular fat from Hu sheep

Jing Li,Youyou Yang,Chaohua Tang,Shengnan Yue,Qingyu Zhao,Fadi Li,Junmin Zhang

Intramuscular fat (IMF) content is associated with lamb flavor and largely varies between individuals of the same breed. However, studies investigating the effects of IMF variations on lipid profiles and aroma compounds are limited. Here, we performed lipidomic and volatilomic profiling of high-IMF and low-IMF Hu lambs. Triglycerides and diglycerides in the high-IMF group were significantly higher than those in the low-IMF group ( p  < 0.05). Seventy-nine of 842 lipids identified were significantly different between the groups under positive and negative ion modes (variable importance in projection > 1, p  < 0.05). Volatilomic analyses revealed that the aroma profiles also differed between the groups. Fifteen aroma compounds, mainly originating from lipid oxidation, could be responsible for this difference. Thus, our findings provide a comprehensive understanding of the increases in IMF content that drive consumers’ satisfaction and also provide a basis for underpinning breeding value for IMF.

Promoted Formation of Pyrazines and Sulfur-Containing Volatile Compounds through Interaction of Extra-Added Glutathione or Its Constituent Amino Acids and Secondary Products of Thermally Degraded N-(1-Deoxy-d-ribulos-1-yl)-Glutathione

Linhui Feng,Heping Cui,Pusen Chen,Khizar Hayat,Xiaoming Zhang,Chi-Tang Ho

An Amadori rearrangement product (ARP) derived from ribose (Rib) and glutathione (GSH) was prepared and identified as N-(1-deoxy-d-ribulos-1-yl)-glutathione by ultraperformance liquid chromatography–tandem mass spectrometry and NMR. Thermal treatment of the ARP aqueous solution was conducted, and a relatively high temperature was found to accelerate the degradation of the ARP. The concentration of furans formed at 120 °C was more than 6.39 times that at 100 °C, and especially, the high temperature favored the formation of furfural and 4-hydroxy-5-methyl-3(2H)-furanone through deoxyosone dehydration. The promoting role of extra-added GSH or its constituent amino acids was investigated in the volatile formation during thermal processing of the ARP. Both, the added GSH and its constituent amino acids, could timely capture glyoxal (GO) and methylglyoxal (MGO) to facilitate Strecker degradation, which improved pyrazine formation. Compared with glycine and glutamic acid, cysteine was the most effective extra-added amino acid to react with GO and MGO to produce pyrazine and methylpyrazine. More importantly, the cysteine degraded from extra-added GSH effectively accelerated the generation of sulfur-containing volatile compounds through the reaction of cysteine degradation products with furans and shorter-chain α-dicarbonyl compounds.