INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2014
·
IF 2.235
Yuyuan Deng,Qin Zhang,Huachuan Zhang,Chengxi Zhang,Wenhu Wang,Yi Gu
To study oxazine ring formation in benzoxazine synthesis from phenol, primary amine and formaldehyde, reactions between 2-phenylaminomethylphenol (Mannich base) and formaldehyde in homogeneous dioxane/water solution are researched. Reaction orders, rate constants at different temperatures, and activation energy are calculated, the process of reaction is proposed, and the influence of acid and base is discussed. The reaction can occur at low temperature and generate the product 3,4-dihydro-2H-3-phenyl-1,3-benzoxazine. No intermediate 2-(N-hydroxymethyl-N-phenylamino)methylphenols are observed. The concentration of a Mannich base has little effect on the reaction rate, while the reaction is first-order to formaldehyde. Based on chemical properties of formaldehyde in aqueous solution, the reaction process includes the following three steps: degradation of poly(oxymethylene) glycols to methylene glycol, dehydration of methylene glycol to formaldehyde molecule, and the reaction between a Mannich base and formaldehyde molecule to benzoxazine. Dehydration of methylene glycols to formaldehyde molecules is the rate-controlling step.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2013
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IF 2.206
Yucui Hou,Yuehong Ren,Wei Peng,Shuhang Ren,Weize Wu
Phenolic compounds, which are important substances in industry, are mainly derived from coal liquefaction oil, coal tar, and petroleum, and also from biomass via pyrolysis. However, the traditional process of separation of phenols from oil using water, NaOH, and H2SO4 causes serious environmental problems. In this work, imidazolium-based ionic liquids (ILs) were used to extract phenol from a model oil of hexane and phenol in order to reduce environmental risk. It was found that these ILs could successfully separate phenols from hexane, and a small amount of [Bmim]Cl, equimolar to that of phenol in hexane, was enough to extract phenol with a high extraction efficiency of 99%. Anions of imidazolium-based ILs have a significant influence on the phenol extraction efficiency, which follows the order: Cl– > Br– > BF4– > PF6–. But the cation of these ILs shows a relatively small influence on the extraction. Particularly, [Bmim]Cl shows best performance in terms of phenol extraction efficiency. Furthermore, it is not sensitive to temperature changes and can be performed at ambient temperature. The extracted phenol in ILs could be recovered by evaporation, and the regenerated ILs could be reused for four cycles with no obvious loss in the phenol extraction efficiency. [Bmim]Cl was also used to extract phenols from real coal liquefaction oil, and the extraction efficiency of phenols could reach 90%.
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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
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2013
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IF 2.487
Huijun Liu,Hong Wang,Caixia Li,Lichao Wang,Zaifa Pan,Lili Wang
Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/mass spectrometry (GC/MS) method was applied for the investigation of low molecular weight volatile organic metabolites (VOMs) in pleural effusion samples. Three important HS-SPME experimental parameters that influence extraction efficiency (fiber coating, extraction time and temperature of sampling) were optimized by a univariate optimization design. The highest extraction efficiency was obtained when sampling was performed at 50 °C for 10 min under agitation using a carboxen/polydimethylsiloxane (CAR/PDMS) fiber. A total of 36 volatile metabolites belonging to nine distinct chemical classes were identified in 40 pleural effusion samples (20 malignant effusions from lung cancer patients and 20 benign effusions from inflammatory patients). Ketones, alcohols, and benzene derivatives were the main chemical classes for the metabolomic profile of malignant effusions. The average peak areas of ketones and alcohols were much higher in malignant group compared to benign group. Together with phenols, they exhibit significant differences ( P < 0.05) between the two groups. Particularly, the average peak areas of cyclohexanone and 2-ethyl-1-hexanol in malignant effusions were significantly higher than those in benign ones. Furthermore, of the 36 identified metabolites, 5 compounds including cyclohexanone and 2-ethyl-1-hexanol were found to be statistically different (Student's t -test, P < 0.05) between the two groups by statistical analysis based on the peak areas of all identified metabolites. Among them, cyclohexanone and 2-ethyl-1-hexanol might be considered as candidate biomarkers of lung cancer to differentiate malignant from benign effusions. The results show that HS-SPME-GC/MS is a simple, rapid, sensitive and solvent-free method for the determination of VOMs in pleural effusion samples. Pleural effusion is a valuable sample source for observation of changes in VOMs for differentiation between lung cancer patients and inflammatory individuals.
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NANOTECHNOLOGY
·
2015
·Vol. 26
·期 45
·455302
·
IF 3.821
Shirong Yu,Ying Chang,Conghui Yuan,Shuang Wang,Jie Mao,Guorong Chen,Weiang Luo,Yiting Xu,Lizong Dai
Exploitation of facile and versatile synthetic approaches to polymeric nanoarchitectures is of great interest in polymer science and engineering. Herein, we show that a simple hydrothermal route using double-solvents as reaction media has the ability to generate polymer nanospheres with tunable morphologies and components. In this one-pot approach, condensation polymerization of a resol precursor and radical polymerization of styrene are allowed to occur simultaneously under hydrothermal treatment. The synergistic self-organization of phenol-formaldehyde crosslinked networks and polystyrene chains leads to the formation of well-defined hollow nanospheres with adjustable shell thickness or even Janus particles comprising a solid hemisphere and a hollow hemisphere. Furthermore, control over the composition of the hollow polymer nanospheres can be easily achieved by introducing a third monomer into the hydrothermal system.
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TETRAHEDRON
·
2015
·
IF 2.641
Biquan Xiong,Kui Zeng,Shanshan Zhang,Yongbo Zhou,Chak-Tong Au,Shuang-Feng Yin
A novel copper-catalyzed method for the direct esterification of P(O)–OH compounds using phenols as efficient esterification reagents is illustrated. It is a simple way to generate a broad spectrum of functionalized O -aryl phosphinates , phosphonates , and phosphates from basic starting materials with moderate to excellent yields.
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Catalysis Science & Technology
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2015
·Vol. 5
·期 4
·2300-2304
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IF 5.426
Gang Feng,Ping Chen,Hui Lou
Phenol is an important component of pyrolysis bio-oil, especially from lignin, and the conversion of phenol is crucial for the production of biofuel. A cost-effective and efficient catalyst is worth developing in the hydrogenation of phenol. Herein we report that supported palladium nanoparticles on carbon–nitrogen composites with high surface area are highly active for aqueous-phase hydrogenation of phenol. The conversion of phenol was 91.7% within 1 h at 80 °C. Higher activity was achieved at higher temperature. The synergy between palladium nanoparticles and the carbon–nitrogen composite support accelerated the hydrogenation of phenol, which clarified the crucial role played by the support. The hydrogenation of phenol highlights the potential of these catalysts for upgrading bio-oil.
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Chemistry-An Asian Journal
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2015
·Vol. 10
·期 5
·1177-1183
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IF 4.587
Shuai Zhao,Haining Wang,Lanxia Xin,Jian Cui,Yehai Yan
Graphical Easy as 2, 3, 4 : 2-(3,4-Dihydroxyphenyl) pyrrolidine grafted graphene was developed as a competent platform for covalent functionalization of graphene, from which four typical but not exclusive graphene-derived materials of magnetic graphene-FeCl 3 complex, phenolic-, epoxide-, and methacryloyl-functionalized graphenes were successfully prepared. Covalent functionalization has proven an effective solution for graphene to realize its revolutionary potential in real applications, whereas the platform strategy (a reactive graphene-based material acting as the platform to undergo post-reactions for generation of various graphene-derived materials) is an attractive option to execute efficiently such a task. This contribution demonstrates that 2-(3,4-dihydroxyphenyl) pyrrolidine (DHPP) grafted graphene, G-OH, is a competent platform. Four typical but not exclusive graphene-derived materials have been prepared from G-OH by using the chemical virtue of each DHPP unit having three categories totaling six reactive sites. The controlled feature of 1,3-dipolar cycloaddition for the synthesis of G-OH ensures that the electronic structure and properties of pristine graphene are succeeded largely by G-OH and thus its derivatives. A promising alternative to graphene oxide, which has been widely used as a platform to prepare the graphene-derived materials but suffers from some intrinsic disadvantages, is thus developed.
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FOOD CHEMISTRY
·
2014
·
IF 3.259
Zai-yong Li,Hong-jiang Quan,Cheng-bin Gong,Yu-zhu Yang,Qian Tang,Yu-bo Wei,Xue-bing Ma,Hon-wah Lam
A novel photoresponsive molecularly imprinted polymer (MIP) was developed for the selective extraction of guanine from complex samples. The photoresponsive MIP was fabricated using guanine as the template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as the functional monomer, and water-soluble triethanolamine trimethacrylate as the cross-linker. The MIP displayed good selectivity toward guanine with a dissociation constant of (2.70 ± 0.16) × 10 −5 mol L −1 in aqueous media. The density of the guanine-specific receptor sites in the MIP material was (4.49 ± 0.22) μmol g −1 . Quantitatively release and uptake of guanine by the MIP occured with irradiation at 365 and 440 nm, respectively. The MIP could efficiently extract guanine from beer and then release it into aqueous media under photocontrol. This method could be used for selective separation and subsequent determination of a specific analytes from complex samples.
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CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Zihang Cheng,Fenglian Fu,Yansong Pang,Bing Tang,Jianwei Lu
Currently, organic pollution is becoming increasingly severe with continued industrialization. In this study, the characterization of acid-washed zero-valent aluminium (AW-ZVAl) and the mechanism of using AW-ZVAl/Air/H + system in the presence of H 2 O 2 to remove phenol were investigated. The influencing factors including acid washing time, AW-ZVAl concentration, pH, H 2 O 2 concentration, air or N 2 conditions, and humic acid (HA) on phenol removal were studied. AW-ZVAl exhibited a greater capacity to remove phenol than that of ZVAl. In the presence of 4.0 mM H 2 O 2 , the phenol concentration decreased from initial 20.0 mg/L to 0.3 mg/L by 6.0 g/L AW-ZVAl in 3 h at initial pH 2.7. The addition of H 2 O 2 into AW-ZVAl/Air/H + system facilitated the reaction due to the enhancement of hydroxyl radicals generation, while the addition of HA inhibited the reaction due to the competitive reaction of HA and phenol with hydroxyl radicals. The reusing of AW-ZVAl showed that the AW-ZVAl was consistently effective in 5 cycles. The removal mechanism of phenol in the AW-ZVAl/Air/H + and AW-ZVAl/N 2 /H + were discussed. This study demonstrates that AW-ZVAl has a great potential to be applied in treating wastewater containing organic pollutants.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 11
·1550-1563
·
IF 1.42
Yan Hua,Lu Chun-xiang,Jing De-qi,Hou Xiang-lin
Chemical degradation of diglycidyl ether of bisphenol A (DGEBA) epoxy resin cured with an aliphatic amine in supercritical 1-propanol was investigated under different reaction temperature and time. The combination of GC-MS and LC-MS proved that the epoxy resin was decomposed to five main products including phenol, 4-isopropylphenol, 4-isopropenylphenol, bisphenol A, and 4,4′-(cyclopropane-1,1-diyl)diphenol. The 13 C-NMR results verified the chemical structures of the degradation products. The change of the products’ yield with time was evaluated by an effective means of HPLC. In addition, the GPC analysis confirmed the formation of soluble low molecular weight clusters during the degradation reaction. A possible free-radical reaction mechanism was proposed for chemical depolymerization of the epoxy resin in supercritical 1-propanol. After the homolytic cleavage of the aromatic ether linkages, the resulting bisphenol A biradical either produced 4,4′-(cyclopropane-1,1-diyl)diphenol after intramolecular rearrangement or generated bisphenol A after capturing hydrogen from 1-propanol.
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CATALYSIS LETTERS
·
2015
·Vol. 145
·期 10
·1830-1836
·
IF 2.307
Zhou Yan,Huang Wei,Chen Xiang-Shu,Song Zhi-Bin,Tao Duan-Jian
Abstract Several tetramethylguanidinum-based ionic liquids (TMGILs) were prepared, characterized and used as catalysts in one-pot synthesis of flavanones. The results indicated that TMGILs composed of phenolate anion was beneficial for one-pot synthesis of flavanones, and [TMG][4-MeO–PhO] induced the good yields of flavanones owing to the electron-donating effect of methoxy substituent on phenolate anion. Furthermore, [TMG][4-MeO–PhO] was found to be used repetitively at least five times without obvious decrease in activity and quantity. Graphical Abstract
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OPTICS EXPRESS
·
2015
·Vol. 23
·期 13
·17487-17510
·
IF 3.488
Dibo Hou,Jian Zhang,Zheling Yang,Shu Liu,Pingjie Huang,Guangxin Zhang
The issue of distribution water quality security ensuring is recently attracting global attention due to the potential threat from harmful contaminants. The real-time monitoring based on ultraviolet optical sensors is a promising technique. This method is of reagent-free, low maintenance cost, rapid analysis and wide cover range. However, the ultraviolet absorption spectra are of large size and easily interfered. While within the on-site application, there is almost no prior knowledge like spectral characteristics of potential contaminants before determined. Meanwhile, the concept of normal water quality is also varying due to the operating condition. In this paper, a procedure based on multivariate statistical analysis is proposed to detect distribution water quality anomaly based on ultraviolet optical sensors. Firstly, the principal component analysis is employed to capture the main variety features from the spectral matrix and reduce the dimensionality. A new statistical variable is then constructed and used for evaluating the local outlying degree according to the chi-square distribution in the principal component subspace. The possibility of anomaly of the latest observation is calculated by the accumulation of the outlying degrees from the adjacent previous observations. To develop a more reliable anomaly detection procedure, several key parameters are discussed. By utilizing the proposed methods, the distribution water quality anomalies and the optical abnormal changes can be detected. The contaminants intrusion experiment is conducted in a pilot-scale distribution system by injecting phenol solution. The effectiveness of the proposed procedure is finally testified using the experimental spectral data.
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