乙酸乙酯

Thus, the thermodynamic equilibrium was shifted and the yield of cyclic carbonates was improved.

在乙腈体系中，以不同的乙酸盐作催化剂，研究了CO2与二醇合成环状碳酸酯的反应。

Methods: fudr was esterified with acetic anhydride in the presence of pyridine and 4 dimethylaminopyridine.

在吡啶和4 二甲氨基吡啶存在时，fudr与乙酸酐反应，制备氟尿苷二乙酸酯，并测定其核磁共振氢谱。rp hplc测定其在正辛醇和磷酸盐缓冲液中的分配系数及不同ph缓冲液和组织匀浆中的稳定性。

Treatment of the diacetoxy-calix [4] arene with a series of ditosylates in dry MeCN in the presence of NaOH resulted in formation of electron-rich calix [4] areneocrowns, which reacted with 4, 4'-bipyrindinium and p-bis -benzene at room temperature in dry MeCN to afford self-assembling [2] catenanes by π-π stacking interaction.

以杯[4]芳烃为原料，通过三氟乙酸铊将其氧化成醌，醌类化合物在Zn粉、冰醋酸、少量盐酸和过量的乙酸酐中反应得到双乙酰化产物，利用氢氧化钠使其水解，然后再与各种对甲苯磺酸二酯进行环化反应，得到一系列具有富电子空腔的杯[4]芳烃并冠醚。

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。