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1.
弱酸弱碱多元非线性回归电位返滴定   总被引:2,自引:0,他引:2  
在被测弱酸或弱碱溶液中加入一定量过量NaOH或HCl标准溶液,再返滴入HCl或NaOH标准溶液若干次,依次测定PH玻璃电极在被测溶液中的电极电位。本方法的突优点是不需要活度与浓度的换算,不需要另行测定工作曲线。测定了NaAc和(NH3)2SO4等弱酸弱碱,结果令人满意。  相似文献   

2.
利用溶剂在层状液晶中的渗透性和层状液晶中溶剂层厚度的限定性,在TritonX-100/C10H21OH/H2O体系状液晶中,以饱和Na2C2O4水溶液代替给分水制备水溶性超微粒子材料Na2C2O4,平均粒径约为6nm。  相似文献   

3.
研究了在季胺Ⅰ型强碱性阴离子交换树脂上用NaOH、NaNO3、NaCl和NH4Cl洗提及洗提后的吸附特性。给出了洗提曲线、穿透曲线和工作交换容量。采用NaCl和NaOH混合洗提的工艺,获得了钨浓度高而过剩洗提剂含量低的洗出液。为由洗出液蒸发结晶制取高纯Na2WO4·2H2O开辟了途径。混合洗提的宏观结果表明:由于反离子的存在,Cl-、OH-和在溶液相或交换剂中的扩散系数发生改变,→Cl-及→OH-的交换速度加快了。  相似文献   

4.
弱酸弱碱非线性回归电位返滴定的研究   总被引:1,自引:0,他引:1  
本文提出的方法是在被测弱酸或弱碱溶液中加入一定量过量NaOH或HCl材料溶液,再返滴入HCl或HaOH材料溶液若干次,依次用电位法测定被测溶液中质子浓度,根据有关酸碱平衡和物料平衡原理及非线性回归原理对实验数据进行处理。  相似文献   

5.
利用溶剂在层状液晶中的渗透性和层状液晶中溶剂层厚度的限定性,在TritonX-100/C_(10)H_(21)OH/H_2O体系层状液晶中,以饱和Na_2C_2O_4水溶液代替组分水制备水溶性超微粒子材料Na_2C_2O_4,平均粒径约为6nm.  相似文献   

6.
尚龙生  许乙烈 《分析化学》1997,25(2):205-207
用索氏提取法,NaOH-消解法和超声振荡萃取法提取海藻样品中的石油烃成分,荧光分光光度计测定石油烃含量,结果表明,NaOH-消解能够更有效从样品中提取石油烃,其检测限为0.075mg/kg。  相似文献   

7.
化学法同时测定含氮有机化合物的碳和氮   总被引:3,自引:0,他引:3  
建立了一个新的化学分析方法,即含氮有机化合物与催化剂、氧化剂相混和,在氧气流下于空气浴上加热分解,C转变成CO2,用稀NaOH溶液吸收,以标准HCl溶液滴定;N转变成NH3,以克达尔定氮法测定,测定误差都小于±0.5%。  相似文献   

8.
硼掺杂多晶金刚石薄膜电极的电化学特性   总被引:1,自引:0,他引:1  
朱建中  许春芳 《分析化学》1995,23(7):824-827
用循环伏安法和恒电位法研究了硼掺杂多晶金刚石薄膜电极(DFE)的若干电化学特性。电极面积4×4mm^2。在0.1mol/L KCl,NaNO3,NaOH和KH2PO4+Na2HPO4(pH=6.86)电解质溶液中电势窗口均为-500 ̄+800mV;而在0.1mol/L HCl和H2SO4溶液中电势窗口为-200 ̄+1100mV.K3Fe(CN)6的氧化峰电位为+500mV,与Pt电极测量相同;校正  相似文献   

9.
氯碳酸镁盐的溶解、转化机制及动力学研究   总被引:7,自引:0,他引:7  
采用NH4HCO3溶液逐滴加入浓的MgCl2水溶液中,经回流沸腾制得氯碳酸镁盐的晶体2MgCO3.Mg(OH)2.MgCl2.6H2O。  相似文献   

10.
于京华  崔瑞珍 《分析试验室》1994,13(4):62-62,73
本文利用碱熔液吸收CO2后电导率的变化值与吸收的CO2含量成正比这一关系来测定生料中的含碳量。5%KOH溶液为最佳的吸收溶液。选择了最佳实验条件,在浓H2SO4介质中,煤或黑生料与氧化剂共热产生的CO2由KOH溶液吸收。通过测定KOH溶液吸收CO2前后电导率的变化值来确定含碳量。对标准煤样及黑生料进行了测定,得到了较为满意的结果。  相似文献   

11.
研究了利用铝酸钠溶液碳酸化产生的沉淀, 经胶溶作用制备出纳米氢氧化铝溶胶的过程. 分析了铝酸钠溶液滴加到大量碳酸氢钠溶液中时发生的反应. X射线衍射研究结果表明, 在纳米氢氧化铝溶胶制备过程中, 从无定形氢氧化铝沉淀到拟薄水铝石的晶型转变过程是氢氧化铝沉淀胶溶时溶解再析出的过程. 将碳酸氢钠加入到苛性比为1.7的铝酸钠溶液中, 中和至苛性比为1.3后, 溶液诱导期中的紫外光谱显示270 nm处的Al(OH)3-6吸收增强. 经与含铝原子六配位的晶体紫外光谱对比后表明, 在铝酸钠分解生成氢氧化铝的过程中, 其铝的配位结构从四配位转化为六配位. 拟薄水铝石溶胶粒子的形貌与胶溶所用的酸和分散剂有关.  相似文献   

12.
Chitin from cell walls of Aspergillus Niger mycelium was prepared. A new method for the preparation of high deacetylation degree chitosan was studied in a dilute sodium hydroxide solution at a high pressure. The experimental results indicate that the deacetylation degree of the chitosan can reach 80% under the condition of a 5.00 mol/L sodium hydroxide solution at 0. 1 MPa of pressure for 1 h. This method shows the advantages of the applications in the industry production and environment protection.  相似文献   

13.
A facile method for the preparation of thioacids in moderate to good yields has been developed by hydrolysis of 1-(acylthio)ethaniminium chlorides under a liquid-liquid two phase system consisting of benzene and a sodium hydroxide aqueous solution at room temperature. We have achieved facile preparation of these compounds without use of toxic compounds such as hydrogen sulfide.  相似文献   

14.
A method for the synthesis of hydroxy derivatives of 2, 5-diaryl-1,3,4-oxadiazoles has been developed which consists in the preparation of acetoxy derivatives of oxadiazole with their subsequent saponification by means of an alcoholic solution of sodium hydroxide.  相似文献   

15.
Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose), carrying out the reaction at 100 °C for 60 min.  相似文献   

16.
Da Wei Chen  Zhen Chu Chen 《合成通讯》2013,43(11):1605-1616
A new and facile method for the preparation of arenetellurinic mixed anhydrides is described from diaryl ditellurides and phenyliodine (III) dicarboxylates. Hydrolysis of the arenetellurinic mixed anhydrides gives arenetellurinic anhydrides and a one - pot procedure involving the reaction of diaryl ditellurides with phenyliodine (III) dicarboxylates in a two - phase system of methylene chloride and aqueous solution of sodium hydroxide for the preparation of arenetellurinic anhydrides is provided.  相似文献   

17.
A procedure for the potentiometric determination of D-sorbitol in the solution of a medicinal preparation Poliamin was developed. The procedure involved binding of sorbitol with boric acid to form borosorbic acid, which was subsequently titrated with a standard solution of sodium hydroxide to a constant pH. The effect of pH and the concentrations of reagents on the accuracy of the results of analysis was studied  相似文献   

18.
The preparation of ammonium molybdophosphate (AMP) precipitated directly into the IRA-900 resinous structure and their application to the determination of cesium-137 in waters are described. The sample of water is passed through the resin, which retains the cesium. After the removal of strontium-90 and potassium-40 with 0.1M ammonium nitrate solution, the cesium is eluted with 1M sodium hydroxide solution. The AMP dissolved in the alkaline solution is used to precipitate the cesium by acidifying the solution.  相似文献   

19.
The fluorescing sensor is based on the change in fluorescence intensity of a buffered pH indicator solution entrapped in silicone rubber. Exposure to ammonia increases the pH of the trapped solution; this increases the fluorescence intensity, which is monitored via an optical fibre bundle. Ammonium chloride in 0.001 M sodium hydroxide, or the indicators themselves, can serve as buffers. Effects of sensor preparation and buffer composition on response time, reversibility and sensitivity are discussed.  相似文献   

20.
The most important types of alkaline batteries are described. A method for the determination of chloride and nitrate ions in sodium hydroxide solutions has been developed The analysis is performed in the following manner: the solution is passed through a layer of a cation exchanger in the hydrogenform,wherebythe sodium hydroxide is neutralized. The liberated hydrochloric and nitric acids respectively are determined through titration. This method has been used for the manufacturing control of nickel-cadmium batteries.  相似文献   

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