查询词典 ionization constant

A new method for the separation and purification of chiral mandelic acid by heated benzene extraction and refrigeration crystal was established. The ionization constant of mandelic acid was mensurated by pH potentiometer titration.

采用pH值电位滴定法测定了扁桃酸的离解常数，采用高效液相色谱法考察了扁桃酸在不同溶剂中的溶解度曲线和在苯-水体系中于不同pH值条件时的分配率，建立了热苯萃取和冷却结晶的扁桃酸纯化工艺。

Chiral drugs ; mandelic acid ; ionization constant ; solubility ; mensuration

手性药物；扁桃酸；离解常数；溶解度；测定

Methods The ionization constant was determined with acid-basle titration in acetone/water solutions with different ratios, the pH at half neutralization point was regarded as pKa, the value to infinite diluted in pure water was explored and the lgP was determined with bottle-shaking method by HPLC.

方法采用酸碱滴定法测定各不同体积比的丙酮-水溶液中药物半中和点时的pH值作为药物在该体积比的丙酮-水溶液中的pKa值，再外推至纯水中药物浓度无限稀释时的pKa值；采用HPLC配合摇瓶法测定药物的分配系数。

The solubility curve of mandelic acid in different solvent and the distribute ratio of mandelic acid in benzene-water system in different pH condition were determine by HPLC. The results showed that the ionization constant pK_a of mandelic acid was 5.28, the solubility of mandeli...

研究结果显示，扁桃酸的离解常数pKa值为5.28；扁桃酸在水和苯中的溶解度曲线可分别表示为：S=38.756e0.0354t和S=0.2746e0.0649t；扁桃酸在水和苯中的溶解度差值曲线可分别表示为：ΔS/S1=0.1196t-2.712和ΔS/S1=0.3688e0.0723t；苯是最适合用于冷却结晶的溶剂；热苯萃取扁桃酸的苯水比例可选为1∶1；降低pH值有利于扁桃酸在苯中的分配。

D-amino acid ; Glutathione ; Non-covalent complex ; Electrospray ionization mass spectrometry ; Dissociation constant

D-氨基酸；谷胱甘肽；非共价复合物；电喷雾质谱；解离常数

Key words thin-layer pH-chromatography;ionization constant;organic acid

如果当固定相的［H+］＞＞Ka时，则Ka/［H+］可忽略，这样即可得到Rf值的极限值

This paper analyses several kinds of charge algorism such as constant current, constant voltage and intelligent charge theoretically.

从理论上分析了恒流、恒压和智能等充电算法。

Using analytic continuation in the coupling constant method within the framework of the self-consistent relativistic mean filed theory, we study the energies and the widths of the resonant states in ~(16)O nuclei, and the influences of the coupling constant interval and the Pade approximant order are analyzed.

考察了~(16)O的中子共振态能级，并且详细研究了耦合常数右端点对应能量的变化和Padé多项式的阶数对能量和宽度的影响。结果表明：适当选取耦合常数取值区间可以得到既收敛又稳定的结果。

The angle of every diffraction line of ZSM-5 molecular sieve determinedby X-raydiffraction, we obtained accurate lattice constant by using the least square method, and SiO_2/Al_2O_3 ratio of ZSM-5 molecular sieve according to empirical formula of lattice constant connectedwith SiO_2/Al_2O_3 ratio .

用x射线衍射最小二乘法测定ZSM－5分子筛的晶胞参数，经ZSM－5分子筛硅铝比与晶胞参数关联的经验公式，得到ZSM－5分子筛的硅铝比。

The dynamic characteristics of the rotor running at a constant angular speed or constant acceleration/deceleration were studied.

飞行器的速度变化将会造成等速转子的稳定振幅或等变速转子变速初期振幅的不同。

The teacher likes the honeymouthed little girl very much.

老师很喜欢这个嘴甜的小姑娘。

Mr. Notker Bien's interests are traveling, spending quality time with the family and long-distance-running.

诺特卡·柏恩先生热爱旅游，长跑，以及和家人一起共度美好时光。