Indirect Electroanalysis of 3-Methyl-4-Nitrophenol in Water Using Carbon Fiber Microelectrode Modified with Nickel Tetrasulfonated Phthalocyanine Complex

Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use of a carbon fiber microelectrode modified with a tetrasulfonated nickel phthalocyanine complex for the detection of MNP at a lower potential than that of direct phenol oxidation. The MNP voltammogram showed the presence of an anodic peak at -0.11 V vs SCE, corresponding to the oxidation of the hydroxylamine group generated after the reduction of the nitro group. The effect of buffer pH on the peak current and SWV parameters such as frequency, scan increment, and pulse amplitude were studied and optimized to have better electrochemical response of the proposed sensor. With these optimal parameters, the calibration curve shows that the peak current varied linearly as a function of MNP concentration, leading to a limit of detection (LoD) of 1.1 μg/L. These results show an appreciable sensitivity of the sensor for detecting the MNP at relatively low potentials, making it possible to avoid passivation phenomena.

Design, Synthesis and Antifungal Activity of 6-Fluoro-3,3a,4,5-tetrahydro-2H-pyrazolo[4,3-c]-quinoline-2-carboxamide Derivatives

A series of 6-fluoro-3,3a,4,5-tetrahydro-2H-pyrazolo[4,3-c]quinoline-2-carboxamide derivatives was designed based on the bioisosterism and combination principle in drug design. The target compounds were synthesized from substituted aniline through Michael addition, cyclization, Mannich reaction and condensation with 4-substituted semicarbazides, and the structures were confirmed by mass spectrometry（MS） and 1H NMR. The antifungal assay was carried out in vitro by two-fold dilution. The result shows that all the compounds are of antifungal activities against the tested fungi at different levels.

Synthesis and Crystal Structure of Ethyl 2-(6-(1,3-Dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) Butanoate

The title compound ethyl 2-（6-（1,3-dioxo-4,5,6,7-tetrahydro-lH-isoindol-2（3H）- yl）-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate 3 was synthesized by the reaction of ethyl 2-（6-amino-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate with 4,5,6,7- tetraydrophthalic anhydride, and its structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P2 1/n with a = 9.3469（2）, b = 16.7715（5）, c = 13.7153（4） A, β= 104.9680（10）°, μ = 0.107 mm^-1, Mr = 430.42, V= 2077.08（10） ,A3, Z= 4, Dc = 1.376 g/cm3, F（000） = 904, T= 296（2） K, R = 0.0508 and wR = 0.1478.

STUDIES ON THE SYNTHESIS OF D-GLUCURONIC ACID DERIVATIVES OF 2-BUTOXY-5-FLUORO-3H-4-PYRIMIDONE AND THEIR ANTICANCER ACTIVITIES

2-Butoxy-5-fluoro-3H-4-pyrimidone derivatives of D-glucuronic acid having 0-glycosidic linkage or N-glycosidic linkage were synthesized and their anticancer activity tested.Their structures were confirmed by elementary analysis,IR spectra and ~1HNMR.

Electrochemical Sensors Based on Modification of Carbon Fiber Microelectrode by Nickel Phthalocyanine Polymer for 3-Methyl-4-Nitrophenol Analysis in Water

3-methyl-4-nitrophenol (MNP) is the main by-product of the organophosphate insecticide fenitrothion (FT), used in locust control. MNP is highly toxic because it is an endocrine disruptor and then may cause adverse in the biological systems. Then, it is necessary to develop analytical methods for determination of this pollutant in the environment. In this sense, we reported herein the development of an electrochemical sensor for the detection of 3-methyl-4-nitrophenol (MNP), one of the metabolites of fenitrothion (FT), by using naked and modified carbon fiber microelectrode (CFME) by nickel tetrasulfonated phthalocyanine polymer (CFME/p-NiTSPc). The voltammogram showed that MNP presents one irreversible anodic peak corresponding to the oxidation of the phenol group at 0.9 V vs Ag/AgCl. The effect of pH of the buffer on the peak current and SWV parameters such as frequency, scan increment and pulse amplitude were investigated in order to optimize the electrochemical response of the sensor. The obtained results lead to the following optimum value: pH = 6;frequency = 25 Hz, pulse amplitude = 50 mV, scan increment = 10 mV. With these optimum values, the calibration curves show that the peak current varied linearly upon MNP concentration leading to a limit of detection (LoD) for naked CFME close to 3 μg/L whereas for CFME modified by p-NiTSPc, it reaches 0.75 μg/L. This results prove that the presence of p-NiTSPc increasing the sensitivity of the sensor could be used to monitor 3-methyl-4-nitrophenol residue in real matrix.

3-氟-4-硝基苯酚的合成

研究了含氟中间体3-氟-4-硝基苯酚(FNP)的合成,由间氟苯胺经重氮化、水解、硝化及异构体分离制得。间氟苯胺重氮盐在CuSO4和硫酸介质中,用反应蒸馏技术,水解制得间氟苯酚,收率85%,质量分数95%;间氟苯酚硝化后采用水蒸气蒸馏法,把副产物3-氟-6-硝基苯酚有效除去,再经乙醚萃取、饱和NaCl水溶液洗涤、饱和NaHCO3水溶液洗涤、Na2CO3水溶液中和成盐、酸化、乙醚萃取等后处理,得到质量分数99.6%的FNP,收率23%。

用Pd-Fe/SiO_2常压催化加氢合成3-氟-4-氨基苯酚的研究

以自制的Pd-Fe/SiO2为催化剂,对3-氟-4-硝基苯酚常压催化加氢得到3-氟-4-氨基苯酚,用熔点、元素分析I、R和1H NMR对其结构进行了表征,并确认为目标产物.确定优化工艺条件为:0.1 mol硝基物,催化剂2.6 g/mol硝基物,无水乙醇作溶剂,用量为60 mL,反应温度为40℃,0.1 MPa下加氢反应3 h,收率为98.1%,产物的纯度达98.4%.

Using waste to treat waste:Red mud induced hierarchical porousγ-AlOOH andγ-Al_(2)O_(3) microspheres as superior Pd support for catalytic reduction of 4-nitrophenol

Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.

Uniform assembly of gold nanoparticles on S-doped g-C3N4 nanocomposite for effective conversion of 4-nitrophenol by catalytic reduction

In this work,a simple synthesis of sulfur doped graphitic carbon nitride(S-g-C3N4)act as a support cum stabilizers for gold nanoparticles(Au)and its was characterized by UV–vis and XRD to measure the absorbance and crystallinity,respectively.The functional group and morphology of the samples were identified using FT-IR and TEM.Finally,the Au@S-g-C3N4 nanocatalyst exhibits good catalytic performance and stability in the reduction of hazardous 4-nitrophenol(NP)compared to S-g-C3N4 using Na BH4.Moreover,the Au@S-g-C3N4 nanocomposite holds a good catalytic efficiency(near 100%)achieved by within 5 min.The highest catalytic reduction of NP is due to the synergistic effect of Au nanoparticles decorated on S-g-C3N4.The fast electron transfer reduction mechanism was elucidated and discussed.Excellent reusability and stability of the developed nanocomposites were also observed in consecutive reduction experiments.The filtering and catalyzing device was used for the direct conversion of NP polluted water.This method can open a new avenue for the metal nanoparticles based carbon materials heterogeneous catalyst and its reduction of toxic contaminants.

Ag@g-C_(3)N_(4) Nanocomposite: an Efficient Catalyst Inducing the Reduction of 4-Nitrophenol

In this study,an efficient catalyst Ag@g-C_(3)N_(4) nanocomposite was successfully synthesized through a simple green reaction,and the characterizations through XRD,FTIR,SEM,BET and XPS were also studied.The activities of Ag@g-C_(3)N_(4) were investigated toward the reduction of 4-nitrophenol to their corresponding aminophenol compounds in the presence of excess NaBH_(4) as a reducing agent.The Ag@g-C_(3)N_(4) nanocomposites exhibited high catalytic activities,in which a 92.2%4-nitrophenol conversion in 10 min and the apparent rate constant K_(app)=264.27×10^(-3) min-1were obtained.The as-prepared Ag@g-C_(3)N_(4) nanocomposites showed great potential in catalytically inducing the reduction of 4-nitrophenol,which makes them economically and energy conservation attractive from industrial waste water treatment.

Experimental design for optimization of 4-nitrophenol reduction by green synthesized CeO2/g-C3N4/Ag catalyst using response surface methodology

In this study,the enhancement of catalytic activity of ceria when modified with co-catalysts such as graphitic carbon nitride and silver was establishe d.The material was synthe sized using phytogenic combustion method,a green alternative to the traditional preparative routes.The catalyst was characterized using XRD,FTIR,SEM,EDX,XPS and TEM techniques.The synergistic effect of the composite CeO2/g-C3 N4/Ag was tested for catalytic reduction of 4-nitrophenol in the prese nce of sodium borohydride.The reaction was carried out at room tempe rature without any light source or exte rnal stirring.The individual and combined effects of four parameters,viz.,concentration of 4-NP,amount of catalyst,amount of NaBH4 and time for the reduction of reduction 4-NP were investigated using Box-Behnken design of response surface methodology(RSM).This statistical model was used to optimize the reaction conditions for maximum reduction of 4-NP.The optimum conditions for the reduction reaction are found to be 0.01 mmol/L 4-NP,15 mg catalyst,20 mg NaBH4 and 13.7 min time interval.

Alleviative effect of quercetin on germ cells intoxicated by 3-methyl-4-nitrophenol from diesel exhaust particles

As a component of diesel exhaust particles, 3-methyl-4-nitrophenol （4-nitro-m-cresol, PNMC） is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health. In the present study, the alleviative effect of a common antioxidant flavonoid quercetin on mouse germ cells intoxicated by PNMC was inves- tigated. Results showed that a single intraperitoneal injection of PNMC at 100 mg/kg induced severe testicular damage after one week. PNMC-treated mice showed a significant loss of germ cells （approximate 40% loss of round germ cells）. PNMC caused an increase of hydroxyl radical and hydrogen peroxide production and lipid peroxidation, as well as a decrease in glutathione level, superoxide dismutase and glutathione peroxidase activities. Furthermore, treatment of PNMC increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein BcI-XL in germ cells. In addition, testicular caspase-3 activity was significantly up-regulated and germ cell apoptosis was significantly increased in the PNMC-treated mice. In contrast, combined administration of quercetin at 75 mg/kg significantly attenuated PNMC-induced testicular toxicity. These results indicate that the antioxidant quercetin displays a remarkable protective effect on PNMC-induced oxidative damage in mouse testes and may represent an efficient supplement to attenuate reproductive toxicity by environmental toxicants to ensure healthy sperm production.

Etching graphitic carbon nitride by acid for enhanced photocatalytic activity toward degradation of 4-nitrophenol

Graphitic carbon nitride （g-C3N4） with high photocatalytic activity toward degradation of 4-nitrophenol under visible light irradiation was prepared by HCI etching followed by ammonia neutralization. The structure, morphology, surface area, and photocatalytic properties of the prepared samples were studied. After treatment, the size of the g-C3N4 decreased from several micrometers to several hundred nanometers, and the specific area of the g-C3N4 increased from 11.5 m2/g to 115 m2/g. Meanwhile, the photocatalytic activity of g-C3N4 was significantly improved after treatment toward degradation of 4- nitrophenol under visible light irradiation. The degradation rate constant of the small particle g-C3N4 is 5.7 times of that of bulk g-C3N4, which makes it a promising visible light photocatalyst for future applications for water treatment and environmental remediation.

Ternary Fe3O4@PANI@Au nanocomposites as a magnetic catalyst for degradation of organic dyes

Magnetic Fe_3O_4@PANI@Au nanocomposites are fabricated through electrostatic self-assembly and seed growth methods.The rate constant K_(app) is calculated to be 8.63×10^(-3) s^(-1) at room temperature for the reduction of 4-nitrophenol to 4-aminophenol with an excessive amount of NaBH_4 as a model system showing outstanding catalytic efficiency and stability.For recyclable performance,the catalyst exhibits slight loss in catalytic performance on the conversion of 4-nitrophenol after running for more than 10 cycles.Besides,the smaller and simpler the structure,the easier the molecular structure can be degraded,and the faster the cationic dyes can be degraded than the anionic dyes,which can reveal the selectivity.For practical application,Congo red as a pollutant of the lake water is degraded rapidly after Fe_3O_4@PANI@Au is added to the solution in a few minutes.It has been demonstrated that magnetic Fe_3O_4@PANI@Au nanoparticle composite is a promising catalyst for environment sewage.

Vertical 3D Printed Pd/TiO_(2) Arrays for High Efficiency Photo-assisted Catalytic Water Treatment

Catalytic degradation of organic contaminants is at the frontier of water treatment due to its selectivity,energy savings,and ability to convert harmful contaminants into harmless or even valuable chemical products for recycling.However,achieving sufficiently high performance in the catalytic removal of organic contaminants for practical application is still extremely challenging.Herein,we report a Pd-decorated TiO_(2)(Pd/TiO_(2))hierarchical vertical array for fast and efficient catalytic water treatment.Such a forest-like Pd/TiO_(2) vertical array demonstrates the following distinct advantages over conventional planar or bulk catalytic systems:1)abundant anchoring sites for nanocrystals loading;2)high sunlight absorption;3)efficient mass transfer channels for the reactants and products.As a proof of concept,the Pd/TiO_(2) array demonstrated rapid and efficient photo-assisted catalytic reduction of high concentrations of 4-nitrophenol wastewater(2 g/L,ca.14.38 mmol/L)and its feasibility for continuous flow wastewater treatment.The turnover frequency(TOF)value of the Pd/TiO_(2) array was up to 8.00 min^(-1),which was approximately 4.2 times that of planar Pd/TiO_(2) film with the same area(1.91 min^(-1)).Our strategy of incorporating nanocatalysts with a hierarchical vertical array provides a promising approach to boosting the catalytic performance of catalysts for different chemical reactions.

一种新的柱前衍生RP-HPLC法分析酱腌菜中的生物胺

以4-fluoro-3-nitrobenzo-trifluoride(FNBT)为衍生剂,N,N-diisopropylethyl-amine(DIPEA)为催化剂,建立了一种新的柱前衍生-反高效液相色谱检测法(RP-HPLC)同时测定酱腌菜中的8种生物胺(组胺、色胺、β-苯乙胺、腐胺、酪胺、尸胺、亚精胺及精胺)。采用硼酸盐缓冲溶液为衍生介质,在60℃下衍生反应30 min,使用C18色谱柱分离,以乙腈和超纯水为流动相梯度洗脱,流速1.00m L/min,紫外检测波长242 nm。在0.5~100 mg/L浓度范围内,8种生物胺呈现良好的线性相关(r2≥0.999),方法的检出限(LODs)为0.013~0.053 mg/L,定量限(LOQs)为0.044~0.176 mg/L,加标平均回收率为93.47%~99.87%,相对标准偏差(RSD)为0.47%~3.67%。采用该方法对26种市售酱腌菜中的生物胺进行了分析,发酵型酱腌菜中的生物胺总量范围为40.57~692.82 mg/kg,非发酵型酱腌菜中的生物胺总量范围为9.86~270.93 mg/kg。发酵型酱腌菜中8种生物胺单体的平均含量均高于非发酵型酱腌菜。该方法简单、准确和可靠,可适用于酱腌菜中生物胺的快速分析。