乙酯

Results By using two-phase solvent systems composed of petroleum ether-ethylacetate-methanol-water (22:25:23:17) at the flow rate of 2.0 mL/min, with rotating speed of 800 r/min, and at temperature of 25℃, the yield of d1-tetrahydropalmatine and of protopine purified from the total alkaloids being 16.9% and 14.7%, with purity of 99.3% and 98.8% respectively can be reached.

结果 石油醚－乙酸乙酯－甲醇－水(22：25：23：17)为溶剂体系，流速为2.0 mL/min，仪器转速800 r/min，温度25℃，从延胡索总碱中可一步纯化得到原阿片碱和延胡索乙素，得率分别为16.9%和14.7%，纯度分别为99.3%和98.8%。

Silicone ; hard coating ; silicone resin ; methyltriethoxy silicone ; tetraethoxy silicane ; transparent plastic

有机硅；硬质涂料；硅树脂；甲基三乙氧基硅烷；正硅酸乙酯；透明塑料

Some useful fluorine-containing intermedi-ates were synthesized by the reaction of activated methylenecompounds or silyl enol ether with 2,2-dihydropolyfluoro-alkanoates or 2-hydropolyfluoroalk-2-enoates in the presenceof different bases.

进一步研究表明，在氢化钠的作用下，苯乙腈，苄基苯基甲酮也可以与2-氢多氟-2-烯酸乙酯发生亲核加成反应，苄基苯基甲酮的加成中间体经多聚磷酸环化，得到了间位氟烷基取代的α-萘酚衍生物。

Water samples were extracted and purified and collected by solid-phase extraction LC-18 column. Soil samples were extracted by ethyl acetate/petroleum ether (2:1, by vol) and purified by sulphonation. Wheat sample was extracted by acetonitrile/water (4:1, by vol) and purified and collected by SPE- Florisil column.

水样直接用LC-18固相萃取小柱分离、净化和富集；采用乙酸乙酯／石油醚（体积比2：1）振荡提取，磺化法净化，测定土壤中氯氟吡氧乙酸残留量；以乙腈／水（体积比4：1）为提取剂，氟罗里硅土固相萃取小柱分离、净化，测定小麦样品中氯氟吡氧乙酸的残留量。

Results Eleven compounds were obtained and identified as sarcodonin A, scabronine B, 3β-hydroxy-5α, 8a-epidioxyergosta-6, 22-dien,(22E, 24R)-ergosta-7, 22-diene-3β, 5α, 6β-triol,(22E, 24R)-ergosta-7, 22-diene-3β-ol, benzoic acid, 4-hydroxylben-zaldehyde, 4-monopropanoylbenzenediol, ethy1-β-D-glucopyranoside, thioacetic anhydride,(2S, 2'R, 3S, 4R)-2-(2-hydroxyoctadecanoylamino) docosane-1, 3, 4-triol.

结果共分离鉴定了11个化合物，分别是：sarcodonin A、scabronine B、3β羟－5α，5α-过氧麦角甾－6，22-二烯－3β-醇、(22E，24R)-麦角甾－7，22-二烯－3β，5α，6β三醇、(22E，24R)-麦角甾－7，22-二烯－3β-醇、苯甲酸、对羟基苯甲醛、对羟基苯甲酸乙酯、乙基－β-D-吡喃葡萄糖苷、硫代乙酸酐、（25，2'R，3S，4R）-2-（2-羟基－十八碳酰胺）二十二碳烷－l，3，4-三醇。

This reflected that EMP and HMP pathways and the tricarboxylic acid cycle were very important to the bioreduction.

表明糖酵解途径、磷酸戊糖途径和三羧酸循环的顺利进行对于面包酵母在有机介质中催化4-氯乙酰乙酸乙酯还原反应都是十分重要的。

The structural assignment of Ⅱwas supported by spectral data and was confirmed by the identification of the compound as the product obtained by synthesis from triethyl orthoacetate and 2- cyanot hioacetamide.

结构的指定得到由光谱数据的支持，确认结构是通过原乙酸三乙酯和2-氰基-硫代乙酰胺合成得到的化合物。

Pesticides were extracted from sample with ethyl acetate in an ultrasonic bath, then determined by gas chromatography-mass spectrometry operated in negative chemical ionization mode and quantified in selective ion monitoring mode, and ethion was used as an internal standard.

蔬菜水果样品用乙酸乙酯超声提取，以乙硫磷为内标物，采用GC-NCI-MS的选择离子监测方式进行定性和定量分析。9种有机磷农药的方法检测限为0.12～1.0 μg/kg。

The experimental condition of acetylating method for determining priminary alcohol and secondary alcohol catalyzed by perchloric acid in the medium of analytically pure ethylacetate is proposed.

提出了以高氯酸为催化剂，分析纯乙酸乙酯为介质，乙酰化法测定伯、仲醇的实验条件，实现了对经典方法的改进，简化了操作程

Methods: M-acetaminphen was used as an internal standard, and alkalinized samples of plasma were extracted with ethyl acetate.

以间乙酰氨基酚为内标，血浆样品经碱化后，用乙酸乙酯提取。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。