乙酸乙酯

The results also indicated a low production of acetic acid, acetoin and ethyl acetate, and high amounts of amyl alcohols in all of the ciders.

结果在所有萍果汁也表明了乙酸、乙醛和乙酸乙酯的低产量和大量产生的戊基乙醇。

In addition, the Gibbs free energy and standard equilibrium constant of the reaction were calculated under the different temperature.

采用基团贡献法估算了反应体系中乙酸、乙醇和乙酸乙酯在298.15K标准状态下的生成焓和标准熵，并且估算了这3种物质的热容随温度变化的关系式，计算了不同温度条件下反应的吉布斯自由能和标准平衡常数。

A method for determining contents of seven kinds of residual organic solvents such as methanol, ethanol, methylene chloride, ethyl aetate, toluene, tetrahydrofuran and acetic acid in a new pharmaceutical-developing (UP0044) was established by capillary gas chromatography.

建立了测定新药UP0044中甲醇、乙醇、二氯甲烷、乙酸乙酯、甲苯、四氢呋喃、乙酸7种有机溶剂含量的方法，以确定它们在药物中的残留量和比例。

A vinegary smell is caused by acetic acid, while a nail polish aroma reflects the formation of ethyl acetate.

葡萄酒中也会闻到破败气味。像醋气味是由乙酸造成的，而指甲油味是由乙酸乙酯形成的。

The results also indicated a low production of acetic acid, acetoin and ethyl acetate, and high amounts of amyl alcohols in all of the ciders.

结果在全部萍果汁也表明了乙酸、乙醛和乙酸乙酯旳低产量和大量产生旳戊基乙醇。

The optimum synthetic conditions of ethyl chloroacetate are: molar ratio of chloroacetic acid to ethanol is 1:8, the quantity of catalyst[Fe2(SO4)3 xH2O] is 10% of the mass of chloroacetic acid, reaction time is 1 hour, 5A zeolite was used as dehydrating agent. In these conditions, the yield of ethyl chloroacetate was up to 73%.

用Fe_2(SO_4)_3·xH_2O作为催化剂合成氯乙酸乙酯的较佳反应条件是：酸醇物质的量之比为1：8，催化剂用量为氯乙酸质量的10％，以5A分子筛作为脱水剂，回流时间1h，收率达73％以上。

The products were identified by IR,NMR,MS and elemental analysis. In our method,K.OH was used in place of NaOH to synthesize benzyl ester of 3,5-dimethyl-4-hydroxybenzoic acid,2',6'-dimethyl-4'-(n-succinimidyloxycarbonyl) phenyl-acridinium-9-carboxylate was purified on a silica gel column with chloroform/ethylacetate(4:l,v/v) as eluent and further purified by triturating with hexane/acetone(2:l,v/v).The luminescence produced by DMAE-NHS is a flash light with maximumemission at 0.4s and decay half-time of 0.9s. The luminescence intensity is 6.11x10 cps/mol,which is affected by the composition of trigger and surfactant.

DMAE·NHS的合成是本论文的关键和难点，我们对文献方法进行改进：文献方法用氢氧化钠与3，5-二甲基-4-羟基苯甲酸反应制得3，5-甲基-4-羟基苯甲酸钠，再用3，5-二甲基-4-羟基苯甲酸钠与苄氯作用制备3，5-二甲基-4-羟基苯甲酸苄酯，我们用氢氧化钾代替氢氧化钠，使合成取得成功；在合成2'，6'-二甲基-4'-苯基-吖啶-9-甲酸酯时，文献方法对粗产品进行两次硅胶柱层析纯化，第一次柱层析用氯仿/乙酸乙酯(4：1，Ⅴ：Ⅴ)作溶剂和淋洗剂，第二次柱层析用己烷/丙酮(2：1，Ⅴ：Ⅴ)作溶剂和淋洗剂，按照文献方法得到的不是所需要的化合物，我们只进行第一次柱层析纯化，然后用己烷/丙酮(2：1，Ⅴ：Ⅴ)进行研磨，过滤，洗涤，除去溶于己烷/丙酮(2：1，Ⅴ：Ⅴ)的部分，得到所需要的产品。

Bromo-5-formyl -3-methylpyrrole is an important intermediate of tolyporohin. On the base of introducing the present research and development of tolypo- rohin and pyrroles ramification at home and abroad, an emphasis was made on synthesis of 2-Bromo-5-formyl -3-methylpyrrole and the technical conditions of all steps, which was described as follows. Diethyl 3,5-dimethylpyrrole-2,4-dicarboxylate was made by nitrification, reduction and cycle of ethyl acetoacetate.

由于2-溴-5-甲酰基-3-甲基吡咯是合成托尼卟吩的重要中间体，本文在阐述了当前托尼卟吩及吡咯衍生物的国内外研究和开发的基础上，重点研究了2-溴-5-甲酰基-3-甲基吡咯的合成，并对各步反应进行了工艺研究，具体合成步骤如下：本文通过对乙酰乙酸乙酯的亚硝化、还原、成环，反应生成吡咯单环衍生物2，4-二乙氧羰基-3，5-二甲基吡咯。

Dihydropyrimidin-2 (1H)-ones were synthesized by condensation of aromatic or aliphatic aldehydes, urea and ethyl acetoacetate or acetylacetone one-pot three-component Biginelli condensation in the presence of room temperature ionic liquids as catalysts under solvent-free conditions.

5利用室温离子液体作催化剂，芳香或脂肪醛、尿素和乙酰乙酸乙酯或乙酰丙酮三组分缩合制备3，4-二氢嘧啶-2-酮衍生物。

Bromo-5-formyl -3-methylpyrrole is an important intermediate of tolyporohin. On the base of introducing the present research and development of tolypo- rohin and pyrroles ramification at home and abroad, an emphasis was made on synthesis of 2-Bromo-5-formyl -3-methylpyrrole and the technical conditions of all steps, which was described as follows.

由于2-溴-5-甲基-3-甲基咯是合成托尼吩的重要中间体，本文在阐述了当前托尼吩及咯衍生物的国内外研究和开发的基础上，重点研究了2-溴-5-甲基-3-甲基咯的合成，并对各步反应进行了工艺研究，具体合成步骤如下：本文通过对乙乙酸乙酯的亚硝化、还原、成环，反应生成咯单环衍生物2，4-二乙氧羰基-3，5-二甲基咯。

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。