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1.
A series of fifteen carbamoyl derivatives of O,O‐dimethyl (2,2,2‐trichloro‐l‐hydroxy) ethyl phosphonate (trichlorphon) was synthesized. A number of them showed higher insecticidal activity, having at the same time lower toxicity than the starting biologically active structure. A waste‐free technology for the production of the more promising representatives of this series could possibly be developed in the future.  相似文献   

2.
To examine the photostability of the herbicide chlorimuron‐ethyl (ethyl‐2‐[[[[(4‐methoxy‐6‐chloro‐pyrimidin‐2‐yl)amino]carbonyl]amino]sulfonyl]benzoate) in the field, model experiment with organic solvent was performed. Photolysis of chlorimuron‐ethyl in methanol solution resulted in the formation of seven major and five minor photoproducts, isolated and identified by spectroscopic methods. Major photoproducts reported were formed by the cleavage of sulfonylurea bridge, contraction of sulfonylurea bridge, methylation of urea nitrogen and cyclisation, whereas minor products by dechlorination.  相似文献   

3.
Methylation of chlorimuron‐ethyl with etheral solution of diazomethane gave ethyl‐2‐[[[[(4‐chloro‐6‐methoxy‐2‐pyrimidinyl) N‐methylamino] carbonyl] N‐methylamino] sulfonyl] benzoate (dimethyl derivative of chlorimuron‐ethyl) as the major product along with 4‐chloro‐6‐methoxy‐2‐N‐methylamino pyrimidine, 2‐aminomethyl sulfonyl benzoic acid, ethyl‐2‐[(N‐methylamino) sulfonyl] benzoate, ethyl‐2‐[N,N‐dimethylamino) sulfonyl] benzoate and o‐benzoic sulf‐N‐methylimide as the minor products.  相似文献   

4.
The persistence, distribution and metabolism of [l4C‐phenyl]‐ethyl parathion applied to soil columns in an agricultural farm were investigated under tropical field conditions. Volatilization, soil microbial activity, moisture levels and pH were found to influence the persistence, distribution and metabolism of this pesticide in the soil. There was rapid distribution of the pesticide in the soil matrix with time resulting in high levels of bound residues which reduced the overall rate of disappearance of parathion residues from the soil. The soil was slightly acidic but the metabolites, paraoxon, p‐nitrophenol and p‐aminophenol were detected in the soil extracts 7 days after pesticide application. After 72 days, 43.7% of the applied pesticide remained in soil composed of 18.9% extractable and 24.8% bound residues. A mechanism for the metabolism of ethyl parathion in this soil is given.  相似文献   

5.
Diuron samples at 40mg/L concentration were photolyzed with ultraviolet lamps and with natural sunlight to determine if data from ultraviolet lamp photolysis could be used to predict results from sunlight photolysis. Seven photoproducts were identified from the photolysis experiments. The identified photoproducts and the photoproduct yields were essentially the same for the two light sources.  相似文献   

6.
Photodegradation of parathion ethyl in presence of unsaturated biomolecules takes place by sufficient reduction of the phenyl nitro group. Main products are N,0‐dialkenyl hydroxylamino, cis/trans azo, and azoxy derivatives of parathion.  相似文献   

7.

A gas‐liquid‐chromatographic procedure for the quantitative determination of authentic carazolol and carazolol in tablets (Conducton(R)?) has been described. Carazolol in tablets was extracted with absolute alcohol before injecting onto the gas Chromatograph. The concentration range adopted varied between 0.2 mg to 1.0 mg/ml of carazolol in alcohol solution. The results obtained were 97.6%±3.2 and 98.4%±2.6 for the stated and added amounts respectively.  相似文献   

8.
The synthesis of several 6‐n‐propyl‐5‐arylazo‐2‐thiouracil derivatives was achieved. The antithyroid activity of these derivatives has been determined using iodine‐125‐thiocyanate discharge technique in rats, and 6‐n‐propyl‐2‐thiouracil (PTU) as a standard. None of the 5‐arylazo‐2‐thiouracil analogs showed antithyroid activity as compared to PTU. The structure‐activity relationships (SAR) of position 5 in the PTU molecule and the requirements for better binding to the proposed receptor are discussed.  相似文献   

9.
We have performed the photolysis of 2‐methyloxy‐, 2‐ethyloxy‐, 2‐propyloxy‐, 2‐isopropyloxy‐, 2‐(l‐methylbutyl)oxy‐, 2‐cyclohexyloxy‐ and 2‐propargyloxybenzothiazole derivatives. We have studied the influence of polarity of the solvent and presence or absence of oxygen on the course of their photochemical transformations. In general it can be concluded that the cleavage of the substituent‐oxygen bonds occurs preferentially, whereby the main product was identified in most cases to be 2‐benzothiazolinone. The rate of photolysis and the composition of the reaction mixture was dependent upon the presence or absence of oxygen. Photoreactivity of above benzo‐thiazole derivatives was also strongly dependent on the structure of the substituents in the position 2.  相似文献   

10.
Microorganisms capable of degrading di‐n‐butyl phthalate (DBP) were isolated by acclimated and enrichment technique. The adaptation of microorganism to DBP was investigated. The microbial cells were immobilized on ceramic particles. The results showed that the biomass adsorbed on ceramic particles can reach 85 mg dry weight/g carrier. The immobilized microbial cells were used for the treatment of wastewater containing DBP. The results demonstrated that the DBP concentration of the outlet reached the stationary‐state level of less than 1.0 mg/1 within 2 days at inlet DBP concentration of 100mg/l and 12h of hydraulic retention time.  相似文献   

11.
A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO4.  相似文献   

12.
3‐amino‐1: 2: 4‐triazole (AT), a potent weed killer, added to activated sludge, caused immediate and drastic reduction in oxygen uptake by biomass. AT, a known specific inhibitor of catalases of animal and plant sources, did not appreciably alter catalase of activated sludge biomass.  相似文献   

13.
湖滨带温室气体氧化亚氮(N2O)排放研究   总被引:7,自引:0,他引:7  
利用不锈钢气体采集箱,在太湖梅梁湾湖区,沿水体至陆地方向对植被型和裸露型湖滨带进行温室气体N2O的原位排放观测。结果发现两种类型湖滨带N2O排放均显著高于临近的开阔水体,可以达到10~100倍,水位变幅区是湖滨带温室气体N2O排放的峰值区,是陆向和水向辐射区的5~10倍。在观测期间,N2O排放通量的范围为-159.2~1565.6μg·m-2·h-1,具有明显的时空梯度变化,时间上,9月份最高,随着气温的下降和芦苇的衰亡而逐渐减少,在1月份最低;空间上,自水向辐射区至陆向辐射区,先逐渐升高,在水位变幅区达到峰值,然后再降低。该结果初步说明了湖滨带是温室气体N2O的一个极其重要的排放源,而目前IPCC对水体N2O排放的估算可能存在很大的疏漏;同时也从一定程度上反映了湖滨带是湖泊脱氮的重要区域,其对缓解湖泊氮污染起到了举足轻重的作用。  相似文献   

14.
Biodegradation experiments of various polycyclic aromatic hydrocarbons were studied with mixed bacteria culture under aerobic conditions. An easy‐to‐handle clean‐up procedure was developed for PAH and their metabolites simultaneously as well as a gc‐ms‐method to identify and quantify these compounds.

Anthracene and dibenzothiophene are completely degradable in an aqeous system, whereas biodegradation of benzo(k)fluoranthene and benzo(h)quinoline is possible only in an oil‐in‐water‐system with dodecane as cosubstrate. No degradation of nitronaphthalene was observed in aqueous systems. New metabolites are 2,3‐dihydroxybenzothiophene, hydroxybenzothiophenecarbonic acid and benzothiophenequinone for dibenzothiophene and hydroxyfluoranthenic acid for benzo(k)flouranthene. Whereas the former metabolites are degradable under the experimental conditions, the latter accumulates during the degradation experiment.

The results are important for microbiological wastewater treatment, since knowledge of biodegradation processes is indespensable for the successful treatment of PAH‐containing wastewater.  相似文献   

15.
The formation of di‐, tri‐, and tetrachlorobenzenes, and di‐ to hexachlorobiphenyls was demonstrated after thermal degradation of bis(2,4‐dichlorobenzoyl) peroxide alone or in various solvents at 250 °C with yields of up to several percent. Possible radical reactions between solvents and the solute are suggested. PCB congeners are also present in silicone rubber crosslinked by this peroxide.  相似文献   

16.
The electron ionization mass spectra of the clinically used antithyroid agent 6‐n‐propyl‐2‐thiouracil (la), its minor metabolite, 6‐n‐propyluracil (lb) and their synthetic selenium and fluorinated analogs (1c and d) have been examined. The fragmentation pattern of these thiouracil and selenouracil studied bear strong similarities with those previously derived from a study of uracil analogs. Thus, the first step in the fragmentation is a retro Diel‐Alder decomposition with the loss of HCNX (X=O, S or Se) and the production of an ion radical which undergoes further fragmentation pathways which are discussed. 6‐n‐Propyl‐2‐selenouracil (1c) did show more complicated spectra due to the six natural isotopic abundance exhibited by the selenium atom. While the fluorinated analogs (1d) did substantiate the fact that the fragmentation pattern of these derivatives proceed through fragmentation between C2 and N3 bond since this produces the more resonance stabilized ion.  相似文献   

17.
The adsorption characteristics of 1,1,1,2‐tetrafluoroethane (HFC‐134a) on activated carbon were investigated to evaluate the recovery efficiency of HFC‐134a by six activated carbons (two granular activated carbons (GAC1 and GAC2), one high‐surface area activated carbon (HAC), and three activated carbon fibers (ACF10, ACF15, and ACF20)). HFC‐134a adsorption on the activated carbons increased with increase in the specific surface area and pore volume of the activated carbon. The differential heat of the HFC‐134a adsorption decreased with increase in the percentage of the micropore volume to the total pore volume. The adsorption model of HFC‐134a on the activated carbon could be based on the Langmuir model. The constant a of the Langmuir plot of HAC and ACF20 is smaller than GAC1 or GAC2 and ACF10 or ACF15, respectively. The constant Ws of HAC has the largest value. The constant a was correlated to the heat of adsorption. It is concluded that the largest amount of HFC‐134a was adsorbed on HAC, and the least amount of interaction occurred between HFC‐134a and the HAC. The amount of HFC‐134a adsorbed on the activated carbons over time was applied to the Sameshima equation. The adsorption rate constant of HFC‐134a on HAC was the largest. The HAC could be suitable for the recovery of HFC‐134a.  相似文献   

18.
Non‐ortho substituted polychlorinated biphenyl (PCB) congeners can account for the majority of the dioxin‐like toxicity in environmental samples, yet analysis for these congeners is difficult because other PCB congeners co‐elute with them in most Chromatographic methods. An automated method was developed which incorporates a porous graphitic carbon (PGC) column which is commercially available. Non‐ortho substituted congeners were successfully separated from interfering PCB congeners. Recoveries of non‐ortho substituted congeners were consistently reproducible (CV < 9%) when chicken eggs were fortified with individual congeners.  相似文献   

19.
以Cu2Se为原料,用溶胶-凝胶法(Sol-Gel)合成了TiO2/CuO/Cu2O(SeO3)光催化剂,用XRD、FTIR和EDAX等方法进行了表征.探讨了催化剂制备过程中焙烧温度对催化剂组成、晶型结构和光催化去除水中腐殖酸性能的影响.当Cu2Se/TiO2焙烧温度为450℃,焙烧2h时,Cu2Se转化为CuO和Cu2O(SeO3).室温下当TiO2/CuO/Cu2O(SeO3)催化剂投加量为1.5g·l-1,溶液pH7.0时,水中腐殖酸的去除率可达到63.6%。  相似文献   

20.
本文研究了CF_2ClBr-O_3体系在253.7nm紫外光照下所引发的O(~1D)与CF_2ClBr的反应.O(~1D)与CF_2ClBr反应的最终产物为CF_2O,Cl_2,Br_2;实验中得到O(~1D)与CF_2ClBr的反应速率常数为1.01×10~(-10)cm~3·molecule~(-1)·s~(-1),并且对O(~3P)与CF_2ClBr的反应可能性以及 O(~1D)与CF_2ClBr的反应机理进行了讨论.  相似文献   

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