乙酸乙酯

Methods: Sample preparation with acetic ether-QuEChERS, and then five kinds of pesticide residues in celery cabbage were determined by gas chromatography with electron detector.

采用乙酸乙酯－QuEChERS法进行样品前处理，结合气相色谱－电子捕获检测器对大白菜中5种常见拟除虫菊酯农药残留进行检测分析。

The graft copolymerization of butyl acrylateonto chloroprene rubber is carried out in methylbenzene-ethyl acetate solvent by using a new type of efficient initiator.

以一种新型的高效引发剂，在甲苯-乙酸乙酯混合溶剂中进行氯丁橡胶与丙烯酸丁酯的接枝共聚反应。

A new type of difunctional initiator (benzyl dibromide, ethyl dibromoacetate) was proposed in this paper and used to synthesize poly based triblock copolymers such as PSt-PBA-PSt, PMMA-PBA-PMMA.

本论文提出一种新型ATRP双官能团引发剂(如α，α-二溴化苄、α，α-二溴乙酸乙酯)，并用聚合反应速度法、GPC法、核磁分析法进行双官能度的验证，并通过两步聚合合成以聚丙烯酸酯为中间嵌段、苯乙烯或甲基丙烯酸甲酯为两端嵌段的ABA型三嵌段共聚物。

When lactide was purified byethyl acetate for 4 times, it was pure enough to polymerize to be PLA.

以乙酸乙酯作为重结晶溶剂，当重结晶次数达到四次后，其纯度已达到丙交酯聚合的基本要求。

The analysis of the components and contents of volatile material indicated that fruit of apples treated with 2 and 4ml/kg of ethanol increased the content and kinds of the characteristic volatile and improved flavor and quality in apple, while the fruit treated with 6ml/kg of ethanol produced higher contents of volatile material and developed off-flavor. Fruit of'Yar'pear treated with 2 and 4ml/kg of ethanol increased the sweet taste and aroma, but higher ethanol concentration showed off-flavor.

对苹果挥发性物质成分的分析表明，2及4ml/kg的乙醇处理增加了苹果特征风味挥发性物质的组分及含量，使水果呈现果香和花香，改善了苹果的品质，而6ml/kg的乙醇处理也能增加苹果果香，但由于强烈果香味的乙酸乙酯等组分在所增加的挥发性物质中所占比例较大，果实呈现浓烈的果香，并使果实的在口中的余味较差，在感官评价中稍差。2和4ml/kg的乙醇处理增加鸭梨甜味，并具有清爽的果香味，而高剂量的乙醇处理余味较差。4ml/kg乙醇处理，在挥发性物质组分数量上与对照差异不大，但却使乙醇形成酯类增加，使鸭梨果实呈现浓郁的果香。

F. which belongs to the Celastraceae Tripterygium plant, its extraction acetylacetic ester was used in clinic preparation, the primary component is epoxy terpenoid lactone.

为卫矛科雷公藤属植物，临床制剂使用的是雷公藤根的乙酸乙酯提取物，主要成分为环氧二萜内酯类化合物。

The synthesis of the intermediate amidetriazinone was a crucial step in the synthesis of triazinone. Ethyl acetate was used as the initial material then was carried out for five steps hydrazine hydrate, triphosgene, chloroacetone, hydrazine hydrate respectively with the yield of 59.8%.

三嗪酮类化合物的合成关键是中间体氨基三嗪酮，本文以乙酸乙酯为起始原料，经过酯的肼解、成环反应、胺的烷基化、酮和肼的缩合、酰胺的水解五步反应合成中间体氨基三嗪酮，其收率达59.8%。

Could keep above 95% in the fixed beds. In order to achieve high stereo-selectivity with yeast, ethyl acetoacetate was used as the model substrate,and a novel approach was proposed to selectively inhibit R-enzymes in yeast before reaction.

以乙酰乙酸乙酯为模型底物，以丙烯酸、乙醚、二甲基亚砜、丙烯酰胺、正己烷等有机溶剂选择性地抑制酵母中R型酶，提高反应立体选择性。

7-Hydroxy-4-methylcoumarin was synthesized from ethyl acetoacetate and m-dihydroxybenzene by the Pechmann condensation using phenyl sulfonic acid as catalyst under solvent-free conditions.

摘 要：以苯磺酸作催化剂，乙酰乙酸乙酯和间苯二酚为原料，通过Pechmann缩合反应合成7-羟基-4-甲基香豆素。

Synthesis 3,5-dihydroxytoluene by ethyl acetoacetate and diketene as material(yield 6%),by 3-methyl-4-chlorophenol and KOH as material(yield 30-40%)respectively,It was solved for product separation and purify.

分别以乙酰乙酸乙酯与双乙烯酮为原料(收率6%)、3-甲基-4-氯苯酚与氢氧化钾为原料(收率30-40%)合成了3，5-二羟基甲苯，解决了产品分离纯化问题。3-甲基-4-氯苯酚路线进行了中试，中试收率为20%。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。