Synthesis, Crystal Structure and Fungicidal Activity of (Z)-3,3-Dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one O-2-Chlorobenzyl Oxime Nitrate

The title compound has been synthesized by the reaction of 3,3-dimethyl-1-（1H-1,2,4-triazol-1-yl）butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65～68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481（8）, b = 9.3351（5）, c = 13.1911（7） , β = 98.9450（10）°, Z = 4, V = 1769.67（17） 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F（000） = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections （I 2σ（I））. X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L.

2-氨基-5-硝基苯酚的合成

以邻氨基苯酚和尿素为原料 ,对环合、硝化、碱性水解的传统工艺进行改进 ,合成了 2 氨基 5 硝基苯酚。研究了影响环合反应的因素 ,优化了反应条件 ,总收率为 80 0 %。最优反应条件为 :n (邻氨基苯酚 )∶n (尿素 ) =1 0 0∶1 0 5 ,于 115℃反应 5 5h ,再硝化、碱性水解得产品。对三步的产品进行了红外光谱分析。传统工艺的收率仅为 36 %～ 5 3% ,三废量大。邻氨基苯酚 -尿素法 ,工艺新颖 ,原料易得、成本低 ,“三废”少。

两步法合成2-氨基-5-硝基苯酚

以邻氨基苯酚和尿素为原料,将传统环合-硝化-水解三步法工艺改为环合硝化-水解两步法合成了2-氨基-5-硝基苯酚(ANP);研究了影响环合硝化反应和水解反应的因素;优化了反应条件。环合硝化反应的最优条件为:n(邻氨基苯酚)∶n(尿素)=1.00∶1.20、环合时间6h、硝酸用量40.2g、硫酸用量20g、硝化时间3h、硝化温度70℃,在此条件下中间产物6-硝基苯并噁唑酮的收率为90.2%;水解反应的最优条件为:体积分数95%的乙醇为溶剂、n(6-硝基苯并噁唑酮)∶n(氢氧化钠)=1.0∶3.3、水解温度80℃、水解时间15h,在此条件下ANP收率为81.2%。两步反应ANP的总收率为73.2%。对产品进行了元素分析和红外光谱表征,确认终产物为ANP。该方法成本低,ANP总收率高,溶剂可回收,三废量少。

Changes of Nitrate Reductase Activity in Cucumber Seedlings in Response to Nitrate Stress

In China, nitrogen fertilizer application rates in intensive agricultural systems have increased dramatically in recent years, especially in protected vegetable production systems. This excessive use of nitrogen fertilizer has resulted in soil secondary salinization, which has become a significant environmental stress for crops such as cucumber, in the protected farmland of China. So it is necessary to illuminate how crops respond to nitrate stress. The objective of this work was to examine the effects of increased nitrate concentration [14 （CK） and 140 mmol L^-1 （T）] on NO3- concentration, and in vitro and in vivo nitrate reductase activities in the roots and leaves of cucumber （Cucumis sativus L. cv. Xintaimici） seedlings with hydroponic culture. The results showed that the NO3- concentration in the roots and leaves of T seedlings significantly increased over treatment course, and at 12 d increased by 1.08 and 1.72 times with respect to CK seedlings, respectively; in vitro nitrate reductase activity of T was increased dramatically to 1.74 times of CK in the roots at 2 d and 1.56 times of CK in the leaves at 6 d, and then decreased. At 12 d, in vitro activity was still 24.3% higher in the roots and only 9.9% lower in the leaves than CK. Compared with in vitro nitrate reductase activity, in vivo activity responded differently to the increase of treatment time. At the beginning, in vivo nitrate reductase activity in the roots and leaves of T had no significant difference from CK, whereas with the increase of treatment duration, the activity decreased. At 12 d, in vivo activity in the roots and leaves of T lowered by 20.1 and 52.8% with respect to CK, respectively. This evidence suggests that posttranslational activation of nitrate reductase in cucumber seedlings may be seriously inhibited by nitrate stress.

The diffusive fluxes of inorganic nitrogen across the intertidal sediment-water interface of the Changjiang Estuary in China

Ammonium and nitrate concentrations were analyzed in near-bottom water and pore water collected from ten stations of the intertidal flat of the Changjiang Estuary during April, July, November and February. The magnitudes of the benthic exchange fluxes were determined on the basis of concentration gradients of ammonium and nitrate at the near-bottom water and interstitial water interface in combination with calculations of a modified Fick＇ s first law. Ammonium fluxes varied from - 5.05 to 1.43 μg/（ cm^2·d） and were greatly regulated by the production of ammonium in surface sediments, while nitrate fluxes ranged from - 0. 38 to 1.36 μg/ （ cm^2·d） and were dominated by nitrate concentrations in the tidal water. It was found that ammonium was mainly released from sediments into water columns at most of stations whereas nitrate was mostly diffused from overlying waters to intertidal sediments. In total, 823.75 t/a ammonium-N was passed from intertidal sediments to water while about 521.90 t/a nitrate-N was removed from overlying waters to intertidal sediments. This suggests that intertidal sediments had the significant influence on modulating inorganic nitrogen in the tidal water.

Non-isothermal oxidation of coal with Ce(NO3)3 and Cu(NO3)2 additives

Non-isothermal oxidation of brown coal with 5 wt% of Cu(NO3)2, 5 wt% of Ce(NO3)3 and {2.5 wt% Cu(NO3)2 + 2.5 wt% Ce(NO3)3} additives was studied. The introduction of additives was carried out by an incipient wet impregnation method to ensure uniform distribution of cerium and copper nitrates within the structure of coal powdery samples (according to SEM and EDX mapping). The samples reactivity was studied in an isothermal oxidation regime at 200 °C (1 h) and by DSC/TGA at 2.5 °C/min heating rate. The additives implementation was found to reduce significantly the oxidation onset temperature (△Ti = 20-55 °C), the samples oxidation delay time (△ti= 2-22 min) and overall duration of the oxidation process (△tc = 8-16 min). The additives efficiency could be graded in accordance with the activation on the coal oxidation in the following row: Cu(NO3)2 >{Cu(NO3)2 + Ce(NO3)3}> Ce(NO3)3. According to the mass spectroscopy, the obtained row of activation correlates well with the initial temperature of the studied nitrate's decomposition (from 190 to 223 °C). A presence of nitrates was found to change significantly the trend of heat release taking place during the oxidation of coal samples (according to DSC/TGA data). The influence of coal morphology and volatiles concern in initial sample on the parameters of the oxidation process was studied as well. Activation energy (Ea) of the coal oxidation was calculated using Coats-Redfern method. Maximum decrease in Ea from 69 to 58 kJ/mol was observed for the samples with Cu(NO3)2. Graphical abstract.

Enhanced nitrate reduction in water by a combined bio-electrochemical system of microbial fuel cells and submerged aquatic plant Ceratophyllum demersum

High nitrate(NO_3^-)loading in water bodies is a crucial factor inducing the eutrophication of lakes.We tried to enhance NO_3^-reduction in overlying water by coupling sediment microbial fuel cells(SMFCs)with submerged aquatic plant Ceratophyllum demersum.A comparative study was conducted by setting four treatments:open-circuit SMFC(Control),closed-circuit SMFC(SMFC-c),open-circuit SMFC with C.demersum(Plant),and closed-circuit SMFC with C.demersum(P-SMFC-c).The electrochemical parameters were documented to illustrate the bio-electrochemical characteristics of SMFC-c and P-SMFC-c.Removal pathways of NO_3^- in different treatments were studied by adding quantitative^(15)NO_3^- to water column.The results showed that the cathodic reaction in SMFC-c was mainly catalyzed by aerobic organisms attached on the cathode,including algae,Pseudomonas,Bacillus,and Albidiferax.The oxygen secreted by plants significantly improved the power generation of SMFC-c.Both electrogenesis and plants enhanced the complete removal of NO_3^- from the sediment–water system.The complete removal rates of added^(15)N increased by 17.6% and 10.2% for SMFC-c and plant,respectively,when compared with control at the end of experiment.The electrochemical/heterotrophic and aerobic denitrification on cathodes mainly drove the higher reduction of NO_3^- in SMFC-c and plant,respectively.The coexistence of electrogenesis and plants further increased the complete removal of NO_3^- with a rate of 23.1%.The heterotrophic and aerobic denitrifications were simultaneously promoted with a highest abundance of Flavobacterium,Bacillus,Geobacter,Pseudomonas,Rhodobacter,and Arenimonas on the cathode.

Poly[β-(1→4)-2-amino-2-deoxy-D-glucopyranose] based zero valent nickel nanocomposite for efficient reduction of nitrate in water

Chemical reduction of nitrate using metal nanoparticles has received increasing interest due to over-dependence on groundwater and consequence health hazard of the nitrate ion. One major drawback of this technique is the agglomeration of nanoparticles leading to the formation of large floes. A low cost biopolymeric material, poly [β-（1-4）-2-amino-2-deoxy-D-glucopyranose] （β-PADG） obtained from deacetylated chitin was used as stabilizer to synthesize zero valent nickel （ZVNi） nanoparticles. The β-PADG-ZVNi nanocomposite was characterized using infra red （IR）, UV-Vis spectrophotometric techniques and Scanning Electron Microscope （SEM）. The morphology of the composite showed that β-PADG stabilized-ZVNi nanoparticles were present as discrete particles. The mean particle size was estimated to be （7.76 ± 2.98） nm and surface area of 87.10 m2/g. The stabilized-ZVNi nanoparticles exhibited markedly greater reactivity for reduction of nitrate in water with 100% conversion within 2 hr contact owing to less agglomeration. Varying the β-PADG-to-ZVNi ratio and the ZVNi-to-nitrate molar ratio generally led to a faster nitrate reduction. About 3.4-fold difference in the specific reaction rate constant suggests that the application of the β-PADG-stabilizer not only increased the specific surface area of the resultant nanoparticles, but also greatly enhanced the surface reactivity of the nanoparticles per unit area.

Cerium(Ⅳ)ammonium nitrate(CAN)-mediated regioselective synthesis and anticancer activity of 6-substituted 5,8-dimethoxy-1,4-naphthoquinone

6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.

Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution.Under the serious pressure of energy and environment,a green,clean,and sustainable ammonia synthesis route is urgently needed.Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia,which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar,wind,or water energy,without greenhouse gas and toxic gas emissions.Herein,the basic mechanism of the nitrogen reduction reaction(NRR)to ammonia and nitrate reduction reaction(NO_(3)^(-))to ammonia were discussed.The representative approaches and major technologies,such as lithium mediated electrolysis and solid oxide electrolysis cell(SOEC)electrolysis for NRR,high activity catalyst and advanced electrochemical device fabrication for(NO_(3)^(-))RR and electrochemical ammonia synthesis were summarized.Based on the above discussion and analysis,the main challenges and development directions for electrochemical ammonia synthesis were further proposed.

Evaluating the Validity of a Nitrate Quick Test in Different Chinese Soils

Because laboratory tests are expensive and time-consuming and may not be available to farmers, soil nitrate quick tests are required for optimal nitrogen management strategies in China to increase nitrogen use efficiency and to reduce nitrogen losses. A total of 328 soil samples were collected at different soil depths from 225 sites in China, which covered a wide range of climatic and geographic regions, soil types, croplands and soil textures, to evaluate the suitability of a quick reflectometer test method for analysing soil NO3-N in a wide range of soil NO3 concentrations, soil types and cropping systems in China, mainly by comparison of soil NO3-N assessed by a quick-test method （a reflectometer） and a standard laboratory method, i.e., high-performance liquid chromatography （HPLC）. The reflectometer showed excellent agreement with the laboratory HPLC method with regard to soil nitrate contents for all analysed soil samples. The linear regression had slopes of 1 ± 0.08 and intercepts of ± 1.38 mg NO（-,3）-N L^（-1） among different soil types and croplands. Compared with the 1：1 lines, the regression analysis for each soil type showed statistically significant but small differences in slope; the relative difference between the values measured using the two analytical systems varied from -8% to 6%, and there were no differences in intercept except for paddy soil. The reflectometer showed adequate, statistically significant precision in determining soil nitrate contents, and it could therefore be directly used instead of the laboratory methods for soil NO（-,3）-N measurement in China.

Atmospheric wet and dry deposition of dissolved inorganic nitrogen to the South China Sea

At the global scale,atmospheric inputs of nitrogen are an important source of the new nitrogen that supports new marine production,especially in oligotrophic open oceans and marginal seas.This study reports quantities of atmospheric deposition of dissolved inorganic nitrogen(DIN)to the largest marginal sea in the North Pacific(the oligotrophic South China Sea,SCS)based primarily on rainwater sampling in the open northwestern region(Yongxing Island)from 2013 to 2015,and aerosol sampling from the SCS basin in June 2017.Atmospheric wet and dry deposition of DIN and their potential contributions to productivity were estimated.The volume-weighted mean rainwater concentrations during the wet and dry seasons were 4.9 and 18.1μmol L-1 for N+N(NO3-+NO2-),and 5.7 and 4.0μmol L-1 for NH4+,respectively.Rainwater concentrations of DIN were lower in the marginal seas than in the open ocean.The aerosol NO3-concentration was 1.15±1.18μg m-3 during the wet season,which is slightly lower than reported for the East China Sea and East Sea,but higher than in the Arabian Sea.Monthly wet and dry deposition rates ranged from 0.4-3.9 and 0.4-1.2 mmol m-2 mon-1 for NO3-,and 0.2-1.3 and 0.01-0.02 mmol m-2 mon-1 for NH4+,respectively.The annual wet and dry deposition fluxes of DIN were estimated to be 16.8 and 10.1 mmol m-2yr-1,respectively.Compared to other marginal seas,the SCS receives less atmospheric NO3-inputs than the Yellow Sea,East China Sea,East Sea,and northeastern Mediterranean Sea.The total atmospheric DIN deposition may account for 1.8-11.1%of the nitrogen supporting new production and 0.7-1.8%of the nitrogen supporting primary production.