乙酸乙酯

It,s allelchemicals were isolated through extraction, thin-layer chromatography, and column chromatograpathy. After the white clover was infused in ethanol and evaporation, the leavings was dissolved by water. The aqueous extract was extracted by petroleum,chloroform, ethyl acetate and n-Butanol successively, and the bioassay showed that the chloroform phase has obvious inhibitory effect, the inhibitory rate was 44.32%,88.08% on Abutilon theophrasti M., seedling length and root length, 82.08%,92.16% on Echinochloa crusgalli L., seedling length and root length, and the Amaranthus retroflexux L., germination rate is 0, the secondly was ethyl acetate phase.

运用萃取、薄层层析、柱层析等方法对白三叶草地上部分的化感物质进行初步分离，结果表明，白三叶草经乙醇浸提旋转蒸发后用蒸馏水溶解，依次用石油醚、氯仿、乙酸乙酯、正丁醇萃取，生物测定表明氯仿组分对杂草的抑制作用最强，对苘麻芽长和根长抑制率分别为44.32%、88.08%，对稗草芽长和根长的抑制率分别为82.08%、92.16%，反枝苋的发芽率为0；其次是乙酸乙酯相。

Methoxy sec-ethyl acetate, Ethyl acetate, Ethyl forate,α-Pinene,β-Pinene, Camphene, Junipene, Limonene, P-Cymene, Linalool and Terpinole are regarded as the key flavorous components, which result in the peculiar smell and taste in fruits of Rubus L..

综合分析表明，甲氧基次乙基乙酸酯、乙酸乙酯、甲酸乙酯、α-蒎烯、β-蒎烯、莰烯及桧烯、柠檬烯、对伞花烃、芳樟醇、萜品醇类等化合物是四种悬钩子类果实的主要香味成分。

The results showed that the condign technical conditions for preparing the composite were 30℃ for the reaction temperature, 0.8/1 for the molar ratio of ethyl acetate and SiO2, and 6.5% for the concentration of water glass.

结果表明，制备SiO2/NR复合材料较适宜的复合工艺为院水玻璃与乙酸乙酯反应温度30益，乙酸乙酯和水玻璃溶液中所含SiO2的摩尔比n为0.8∶1，水玻璃浓度为6.5%。

Ethyl acetate is one of the most important chemical solvents;nowadays it has a very large demand quantity in the whole world, especially in China.

乙酸乙酯是一种非常有用的基本工业溶剂，目前乙酸乙酯在国内外都有很大的需求。

Ethoxycarbonyl-4,5-dimethyl-pyrrole (7) was prepared from ethylacetoacetate, ethyl formate and methyl ethyl ketone via oximination, Claisen condensation, and reductive condensation. The bromization of compound 7 gave 2-ethoxycarbonyl-3-bromo-4,5-dimethyl-pyrrole(8), which could be transferred to 2-ethoxy-carbonyl-3-brome-4-methyl-5-formyl-pyrrole (9) by the formolation.

由乙酰乙酸乙酯、甲酸乙酯及丁酮等原料经过肟化、Claisen缩合、还原缩合成环得到2-乙氧羰基－4，5-二甲基－吡咯(7)，溴化生成2-乙氧羰基－3-溴4，5-二甲基－吡咯(8)，最后经过甲酰化反应得到目标产物2-乙氧羰基－3-溴－4-甲基－5-甲酰基－吡咯(9)。

In order to investigate the mechanism for this reac-tion, methyl α-bromoacetate or ethyl α-bromoacetate as starting material was added to the solution of phenyl selenoamide in ethanol in 1∶1 or 2∶1 molar ratio under the neutral condition at room temperature. The results indicated that the same product bis or bis diselenide was formed. Byproduct ethyl benzoate was also separated.

为了研究该反应机理，选择α-溴代乙酸甲酯或α-溴代乙酸乙酯在无催化剂、中性条件下，乙醇溶液中与苯基硒代酰胺室温下反应，投料比为1∶1和2∶1，结果也都生成了同一类产物二甲氧羰基甲基二硒醚或二乙氧羰基甲基二硒醚，同时还分离得到了相应的副产物苯甲酸乙酯。

In order to investigate the mechanism for this reaction, methyl α-bromoacetate or ethyl α-bromoacetate as starting material was added to the solution of phenyl selenoamide in ethanol in 1:1 or 2:1 molar ratio under the neutral condition at room temperature. The results indicated that the same product bis or bis diselenide was formed. Byproduct ethyl benzoate was also separated.

为了研究该反应机理，选择α-溴代乙酸甲酯或α-溴代乙酸乙酯在无催化剂、中性条件下，乙醇溶液中与苯基硒代酰胺室温下反应，投料比为1：1和2：1，结果也都生成了同一类产物二甲氧羰基甲基二硒醚或二乙氧羰基甲基二硒醚，同时还分离得到了相应的副产物苯甲酸乙酯。

The antimicrobial test and researched was done on wide distillation of different solvents on Terpenoid, polarity separation of ethanol distillable substance, thin layer chromatography of different polarities and distillation of amylase. The results showed that the active substance distilled by 95% ethanol and V methanol: toluene=3:1 had stronger antimicrobial activity on Agaricus blazei Murrill. The antimicrobial activity of ethyl acetate was stronger than wide distilling substance with ethanol, but the water part has not antimicrobial effect. Two straps of ethyl acetate phase（Rf0.57、Rf0.63）(0.1g/ml)had stronger antimicrobial activity on Agaricus blazei Murrill, the antimicrobial zone on Pseudomonas was 19.3mm. The bacteriostatic activity of chromatography strap of water phase was rather weaker, the water solution (0.5g/g) of amylase had better effect on pathogenic fungus of Agaricus blazei Murrill, its antimicrobial zone on Aspergillus niger, Citrinin, Trichoderma viride were 10.8 mm, 7.9 mm, 5.3 mm.

通过对日本凹顶藻以不同溶剂的粗提、乙醇提取物的极性分离、不同极性的薄层层析和多糖的提取，进行抗菌试验的研究，发现95%乙醇和V甲醇：甲苯为3∶1的提取的活性物质具有较强的抗姬松茸的病原细菌活性，乙酸乙酯相对病原细菌的抑菌强于乙醇的粗提物，而水相基本无抑菌效果，乙酸乙酯相的两个带（Rf0.57、Rf0.63）浓度为0.1g/ml具有较强抗姬松茸病原细菌的活性，对假单孢杆菌抑菌圈达到19.3mm，水相层析带的抑菌活性较弱，多糖的粗提物配成0.25g/g的水溶液对姬松茸病原真菌有较好的抑菌效果对黑曲霉、桔青霉和绿色木霉的抑菌圈分别达到10.8 mm、7.9 mm、5.3 mm。

Using silicotungstic acid as catalyst with the catalyst supported on active carbon,2-methyl-2-ethyl-acetic-1,3-oxathiolane(targeted compound I,an aroma compound with apple flavor )was synthesized by the reaction of ethyl aceto-acetate and 2-mercapto-ethanol.

以活性炭固载硅钨酸作为催化剂，用乙酰乙酸乙酯与巯基乙醇缩和合成了具有浓郁苹果香气的香料化合物2-甲基-2-乙酸乙酯基-1，3-氧硫杂环戊烷。

An agent for a protective film which comprises a liquid mixture of a urethane type compound, methyl ethyl ketone and ethyl acetate and a curing rate enhancing agent comprising an isocyanate type compound and ethyl acetate; and a method for forming a protective film which comprises applying the agent for a protective film on the outer surface of a mold (9) or on the region of the outer surface of the mold (9) except a specific portion as an article to be coated.

本发明提供了一种保护膜制剂和形成保护膜的方法，其中所述保护膜制剂含有聚氨酯型化合物、甲基乙基酮和乙酸乙酯的液体混合物与含有异氰酸酯型化合物和乙酸乙酯的固化增速剂；所述形成保护膜的方法包括将保护膜制剂涂布于模具(9)的外表面或涂布于模具(9)的外表面除了作为待涂布制品的特定部分以外的区域。

I urge any American living outside the country to get an early start checking his/her registration and receiving an absentee ballot, because it can take a while.

我奉劝身在国外的所有美国人早点着手核对登记表，并接收缺席选举人票，因为这得花点时间。

He is too young to join the army.

他太年轻了，还不能参军。