查询词典 ethyl acetate

And the operational condition was as follows: 100-200 mesh silica gel to be the stationary phase, solvent system of methlene chloride: ethyl acetate: ethanol = 80:35:5 to be the eluent, the flow rate of the eluent to be 2.0 mL/min, the feeding concentration of pristinamycins to be 2.26 g/L, the total loading amount of the silica gel to be 0.81 mg/g and the temperature to be 25℃.

优化后的柱层析操作条件为：选用100～200目的硅胶，二氯甲烷：乙酸乙酯：乙醇=80：35：5为洗脱剂，流速为2.0 mL／min，普那霉素的进样浓度为2.26g／L，硅胶的总负载量约为0.81 mg／g，温度为25℃。

This pigment was extracted with 1%NaOH, then was extracted for 3 times with petroleum ether and ethyl acetate.

结果表明，板栗壳色素易溶于碱性水溶液，不溶或难溶于非极性溶剂。

The effects of different entrainers(methanol,acetone,ethyl acetate,petroleum ether and ethanol of different concentrations) on the diosgenin extraction rate were studied.

探讨了乙醇、甲醇、丙酮、乙酸乙酯、石油醚作为夹带剂以及在无夹带剂的条件下，对薯蓣皂素收率的影响。

It is easily soluble in water, acetone and alcohol, slightly soluble in ether, ethyl acetate, chloroform, and pyridine, unsoluble in benzene.

熔点151℃～154℃。易溶于水、丙酮与醇，微溶于醚、乙酸乙酯、氯仿和吡啶，不溶于苯。

Various fractions of tannins with different polarities and relatively narrow molecular weight distribution were obtained by extractions using ether and ethyl acetate sequently.

通过乙醚和乙酸乙酯萃取可得到极性不同的组分。分析表明，各级分的分子量分布范围不同，且相对较窄。

Methods The cultivated Cs fungus HK-1 and natural Cs were extracted with petroleum ether, ethyl acetate, ethanol, and water.

方法人工虫草菌HK-1与天然虫草分别用石油醚、醋酸乙酯、乙醇和水提取。

A new method for the determination of methanol, ethyl acetate and fusel oils in the Chinese spirits by capillary gas chromatography was studied.

建立了一种用毛细管气相色谱法测定白酒中甲醇、乙酸乙酯和杂醇油的方法，并对色谱条件进行了优化。

A new method for the determination of methanol, Ethyl Acetate and fusel oils in sticky rice alcohol by capillary gas chromatography was studied.

建立了一种用毛细管气相色谱法测定糯米酒中甲醇、乙酸乙酯和杂醇油的方法，并对色谱条件进行了优化。

The results showed as follows: 1 Extraction of gelsemium total alkaloids. Total alkaloids were extracted with 95 per cent ethanol. The extract rate was 0.519 per cent and the extract purity were 88.02 per cent and 87.38 per cent; Total alkaloids were extracted with chloroform .The extract rate was 0.416 per cent and the extract purity were 89.02 per cent and 94.52 per cent. 2 Isolation of gelsemium total alkaloids with TLC. Total alkaloids contained five or more alkaloids. The optimal developing agent was chloroform :methanol :ethyl acetate(9:l:0.3),the optimal eluent was methylene chloride:methanol(92:8). 3 Isolation of total alkaloids with column chromatography. Alkaloid A and alkaloid B were obtained, alkaloid B was identified as koumine.

研究结果如下：1、钩吻总碱的提取：用95％的乙醇提取钩吻生物碱提取率为0.519％，其提取物纯度为88.02％、87.35％；用氯仿提取钩吻生物碱提取率为0.416％，其提取物纯度为89.02％、94.52％。2、钩吻总碱的薄层层析分离：总碱中含有5种或5种已上的生物碱；氯仿：甲醇：乙酸乙酯(9：1：0.3)是最佳薄层层析的展开剂；二氯甲烷：甲醇(92：8)是柱层析的最佳洗脱剂。3、钩吻总碱的柱层析分离：共得到两种钩吻生物碱单体成分碱A和碱B，碱B为钩吻素子，碱A可能是钩吻素甲。4、钩吻总碱的急性毒性试验：钩吻总碱小鼠腹腔注射的半数致死量LD_(50是：7.38mg／kg，95％的可信限范围为：6.67mg／kg～7.94mg／kg。

The synthesis of guaifenesin was improved by direct application of the hydrolyzate of epichlorohydrin for the etherification with guaiacol and using toluene and ethyl acetate as the solvents for crystallization and recrystallization, respectively.

通过直接利用环氧氯丙烷的水解液中的 3-氯- 1，2 -丙二醇和改良成品析晶法及重结晶溶剂等工艺改进，愈创甘油醚的总收率可达 80 %。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。