氟化

Nucleophilic opening of the terminalepoxide 57 by a lithium acetylide from 27 in the presence of BF3·EtO furnishedcompound 58, which had the skeleton of target molecule, subsequent conversionsinvolved the introduction of γlactone gave Annonacin.

然后以三氟化硼参与的炔负离子开环氧反应建立分子骨架，得到化合物58。随后经氢化，引入α，β不饱和丁内酯环、去保护等几步反应，就得到Annonacin。

We studied effects of additives in the allylic amination reaction. We found that4NF could improve the reactivity and enantioselectivity.

对于烯丙基胺化反应，我们研究了外加添加剂对对映选择性的影响，我们发现四丁基氟化铵的加入可以大大提高反应速度及对映选择性。

The results indicated that the high level density functional theory calculations can be used to predict the 13C chemical shifts of the modified nanotubes. The calculated results also provided the characteristic chemical shifts values of nitrene (superscript -), carbene (superscript -) and 1,2- and 1, 4-fluorinated nanotubes, which would be helpful for experimental spectrogram assignments. Combined with NMR experiments, these predicted characteristic chemical shifts can be further used to monitor the addition mechanism and the extent of surface modifications on nanotubes.

研究表明高精度的密度泛函理论计算能够用来预测纳米管的13C化学位移，理论研究的结果揭示了氮烯、卡宾以及1，2和1，4氟化的单壁纳米管的若干13C信号特征化学位移值，为实验NMR谱图的归属提供了一定的依据，并且可通过与实验相结合来监测表面官能化碳纳米管加成反应是否发生以及确认其加成方式。

In this dissertation, traditional phase-transfer fluorination and solid-solid-liquid triphase-transfer esterification were studied, respectively.

本论文对传统相转移催化氟化和固一固一液三相相转移催化酯化反应进行了系统的研究。

In this paper, the composition of zinc phosphating solution used at environmental temperature was researched. The composition is as followings: phosphoric acid 100 mL, monometallic sodium orthophosphate 20 g/L, zinc oxide 25 g/L, bluestone 1 g/L, sodium molybdate 1 g/L, sodium fluoride 1 g/L, tartaric acid 1 g/L.

研究了配制锌系磷化液配方：1 L溶液中加入磷酸100 mL，磷酸二氢钠20 g，氧化锌25 g，硫酸铜1 g，钼酸钠1 g，氟化钠1 g，酒石酸1 g。

In order to determine the content of hydrocarbons and halohydrocarbons in uranium hexafluoride,the first step is to passivate the inlet system and ion source of mass-spectrometer.

了测定六氟化铀中烃和卤代烃的含量，首先要对进样系统和质谱计的离子源进行充分的钝化。样品必须全部汽化后方可通入质谱计，否则分馏效应将严重歪曲测量结果。

Influences of derivatization condition are analyzed,such as concentration of boron trifluoride in the solution of methanol,reaction temperature and the reaction time.

阐明三氟化硼在甲醇中的浓度、反应温度和反应时间对衍生化效果的影响。

The crosslinked PEG-20M glass capillary column was prepared by dynamic coating method with boron trifluoride as catalyst,3-glvcidyl-oxypropyl-trimethoxysilane as crosslinking agent.

以PEG－20M为固定相，三氟化硼为催化剂，3－缩甘油氧丙基三甲氧基硅烷（简称KH－560）为交联剂，二氯甲烷为溶剂，对预先用氯化钠沉积法粗糙化的玻璃毛细管柱进行动态涂渍。

The titrant is a mixture of EDTA and sodium fluoride, both mercury film electrode and fluorinion selective electrode are inserted in the titration solution. In a process of titration, both the added volume of titrant and the concentration of mercury ion at each titration point can be obtained simultaneously from the potentials of two electrodes, and then the concentration of each component in the alloy can be obtained from the titration curves by multivariate calibration.

用ED-TA与氟化钠的混合溶液作为滴定剂，被滴定液中同时插入了汞膜电极和氟离子选择电极，在滴定过程中的任一滴定点，溶液中汞离子的浓度和滴定剂的加入体积可由两个电极的电位测定值同时获得，从而可应用多元校正法由相应的滴定曲线求得混合金属中每一种组分的含量。

Optimum conditions are as follows: DMF is used as solvent, compound quaternary ammonium salt as catalyst, n(p-nitrochloro benzene):n=1: 1.2, m:m(p-nitrochloro benzene)=4%, m:m(p-nitrochloro benzene)1:1, and reacted under 155~160℃ for 18 h; reduction reaction is carried out in methanol with Raney nickel, which is used as catalyst; the raw product is added an antioxidant, and distilled simply under reduced pressure to obtain 4-fluoroaniline with excellence quality, purity is over 99.5%, total yield is 89.3%.

实验结果表明，氟化反应的最佳条件为：二甲基甲酰胺为溶剂、复合季铵盐为催化剂，n：n=1：1.2，m（催化剂：m=4%，m：m=1：1，于155~160℃下反应18h；还原反应在甲醇中进行，以阮内镍为催化剂；粗产品加入抗氧剂，减压条件下简单蒸馏得高品位的对氟苯胺。

Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.

Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。

I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.

我来只是现在，'歼灭战perfuming自己与胡努特，那麼，他来到和SAT 。