排序方式: 共有71条查询结果,搜索用时 804 毫秒
51.
交联CMC控制释放除草剂的研究 总被引:3,自引:0,他引:3
本文报道以交联羧甲基纤维素囊化除草剂2,4,5-T、2,4-D和麦草畏二甲基胺盐所制成的控制释放体系的释放性能。研究了交联方法。制品形态、CMC取代度、交联剂用量和载药量等制备工艺条件对控释性能的影响。结果表明,以低取代度的CMC,经较大量甲醛交联制得的粒状制品,具有较好的控制释放性能。 相似文献
52.
Josy Anteveli Osajima Hamilton M. Ishiki Keiko Takashima 《Monatshefte für Chemie / Chemical Monthly》2008,139(1):7-11
Summary. The degradation of imazapyr, an imidazolinone herbicide, in aqueous solution has been investigated with TiO2 slurry as photocatalyst at 30°C under UV radiation. The depletion of imazapyr concentration in an aqueous suspension followed
1st order kinetic behavior. The influence of pH and the charge densities of imazapyr geometries were calculated at the semi-empirical AM1 level, and the effect of temperature
was investigated. The addition of electron acceptors such as potassium persulfate and hydrogen peroxide showed that the rate
constant doubled at least. At higher persulfate concentrations the herbicide degradation was more efficient in direct photolysis
than TiO2-photocatalysis. The degradation rate constant increased by 38% upon variation of the temperature between 20.0 and 50.0°C
and displayed non-Arrhenius behavior. 相似文献
53.
XU Han HU Xu-hong ZOU Xiao-mao ZHU You-quan LIU Bin HU Fang-zhong YANG Hua-zheng 《高等学校化学研究》2012,28(5):824-827
The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli(L.) Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli(L.) Beauv at 100 μg/mL. 相似文献
54.
55.
采用长光程气体池结合傅里叶变换红外光谱仪测得了除草剂2-甲基-4-氯苯氧乙酸(MCPA)与.OH自由基在23℃时的反应速率常数为2.67×10-11cm3/(s.mol),以此估算了在大气中.OH自由基浓度为7×105mol/cm3时,MCPA与.OH自由基反应导致的大气寿命为14.9 h.结果表明,在大气环境中MCPA较容易降解,不会通过大气输送对环境造成广泛和持久性污染. 相似文献
56.
Clemens Lamberth 《Tetrahedron》2019,75(33):4365-4383
An overview is given of the significance of three- and four-membered rings in crop protection chemistry. The main herbicidally, fungicidally, and insecticidally active small ring derivatives are presented, together with their synthesis routes, modes of action and biological efficacies. Also the most important small ring containing natural products, which are active against weeds, insects and fungal plant diseases are covered. In addition, the role of three- and four-membered rings as intermediates in the synthesis of agrochemicals not containing such a small ring component is reported. 相似文献
57.
We evaluated two alternative routes for the arylation of known chlorinated fungicides. The first pathway involved a SRN1 substitution, followed by Stille reaction, while the second consisted in a one step reaction by the Suzuki coupling. Both methodologies were useful to obtain new products that could be potential fungicides. 相似文献
58.
合成了单功能化的柱[5]芳烃单烯体,然后将其与丙烯酰胺(AAM)、交联剂N,N'-亚甲基双丙烯酰胺(MBA)和引发剂偶氮二异丁腈(AIBN)在70 oC下反应12 h后形成含有大环主体柱[5]芳烃的高分子聚合物,将此聚合物分别浸泡于DMSO、水中各1周,并每天更换新鲜的溶剂,最后通过此聚合物的红外光谱图证实成功制备了含有柱[5]芳烃的聚合物水凝胶.利用紫外吸收光谱测试表征了水凝胶对百草枯的吸收作用.将该水凝胶浸入浓度从小到大的百草枯溶液中,发现水凝胶颜色由浅黄色变为棕红色,这是由于水凝胶中的柱[5]芳烃与N,N'-二甲基-4,4'-联吡啶客体分子之间主客体作用形成了含有准轮烷结构的超分子聚合物所致. 相似文献
59.
Simultaneous determination of herbicide residues in tobacco using ultraperformance convergence chromatography coupled with solid‐phase extraction 下载免费PDF全文
Weiyun Guo Daohong Zhang Gangling Tang Wei Liu Jianlong Wang Zhonghao Li Fei Yang 《Journal of separation science》2015,38(5):858-863
A time‐saving and organic solvent efficient method to simultaneously determine six kinds of herbicide residues in tobacco using solid‐phase extraction for sample clean‐up and preconcentration and the highly sensitive ultraperformance convergence chromatography method was developed. Parameters for ultraperformance convergence chromatography, including the choice of stationary phase and modifiers, autobackpressure regulator pressure, column temperature, and the flow rate of mobile solvents, were optimized. The herbicide residues of napropamide, alachlor, quizalofop‐ethyl, diphenamid, metolachlor, and clomazone in tobacco samples were successfully separated and detected at levels as low as 0.0043–0.0086 mg/kg within 5 min using a nonpolar high strength silica C18 selectivity for bases column and methanol as the cosolvent of the mobile phase of carbon dioxide (75–99.9%, v/v). Analysis of tobacco samples had recoveries of 69.8–95.0%, limit of quantitation of 0.0127–0.0245 mg/kg, limit of detection of 0.0043–0.0086 mg/kg, and correlation coefficient of >0.9990. Results support this method as an efficient alternative to current methodologies for the determination of herbicide residues in tobacco. 相似文献
60.
应用中空纤维液相微萃取-高效液相色谱法测定水中二氯喹啉酸、特丁噻草隆、戊炔草胺等3种除草剂的残留量。样品以聚丙烯中空纤维为支撑,正辛醇萃取,以600r·min-1转速在40℃的条件下萃取20min。所得净化液以Inertsil ODS-SP C18色谱柱为分离柱,以甲醇-水(82+18)混合液为流动相,在检测波长220nm处进行测定。3种除草剂在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.20~0.35μg·L-1之间。以地表水样为基体进行加标回收试验,所得回收率在90.6%~106%之间。方法的相对标准偏差(n=6)在3.1%~6.8%之间。 相似文献