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1.
本文在298.15±0.2K测定了九个恒定离子强度不同PH值缓冲溶液中对硝基苯酚有等吸收点的紫外谱图。在恒定总离子旨度为I=0.1-2.0mol/kg条件下, 利用谱图中的光密度数据和测定的PH值, 根据扩展的Debye-Huckel公式外推得到pK°=7.246。K°为对硝基苯酚的热力学解离常数, 本文又提出了用多项式拟合法确定pK°, 其值为7.308。两者在实验误差范围内一致。  相似文献   

2.
本文在298.15±0.2K 测定了九个恒定离子强度不同 pH 值缓冲溶液中对硝基苯酚有等吸收点的紫外谱图.在恒定总离子强度为 I=0.1-2.0mol/kg 条件下,利用谱图中的光密度数据和测定的 pH 值,根据扩展的 Debye-Hückel 公式外推得到 pK°=7.246.K°为对硝基苯酚的热力学解离常数.本文又提出了用多项式拟合法确定 pK°,其值为7.308.两者在实验误差范围内一致.  相似文献   

3.
离子液体液-液萃取-高效液相色谱测定水中酚类化合物   总被引:15,自引:0,他引:15  
建立了离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C4mim][PF6])液-液萃取-高效液相色谱测定水中酚类化合物的方法.研究了水相pH值、萃取时间、水相体积及盐的浓度对萃取的影响.最佳萃取条件分别为:水相pH值为5,萃取时间为40 min,水相体积为60 mL.对比了离子液体对1-辛醇对苯酚、4-硝基苯酚、2-硝基苯酚、2,4-二甲基苯酚和双酚A的富集效率.在最佳条件下,离子液体对5种酚的富集倍率在9~151之间,方法对苯酚、4-硝基苯酚、2-硝基苯酚、2,4-二甲基苯酚和双酚A的检出限分别为:2.0、0.9、0.3、1.8和1.1 μg/L.将该方法应用于自来水、河水、湖水和污水的检测,回收率为87.9%~109.9%.  相似文献   

4.
研究了离子色谱法同时测定硝基苯光降解的中间产物邻硝基苯酚、间硝基苯酚、对硝基苯酚及硝酸根的分析方法.采用7.5mmol/L的碳酸氢钠,1.5mmol/L的碳酸钠混合溶液为淋洗液,紫外检测波长215nm.回收率在96.8%~101.3%之间;RSD小于1.5%;检出限在8.5×10-4以下.  相似文献   

5.
赵俐敏  傅厚暾 《分析化学》1999,27(6):701-703
研究了离子色谱法同时测定硝基荧光降解的中间产物邻硝基苯酚,间硝基苯酚,对硝基苯酚及硝酸根的分析方法。采用7.5mmol/L的碳酸氢钠,1.5mmol/L的碳酸钠混合溶液为淋洗液,紫外检测波长215nm,回收率在96.8% ̄101.3%之间,RSD小于1.5%,检出限在8.5×10^-4以下。  相似文献   

6.
分离和精制     
89.苯酚-水-丁酮三元系统相平衡Ⅱ1956,30,№ 2,305)——本文包括三个部分:1.配制了许多已知组成的苯酚-水-丁酮三元混合物,在45°测定这些混合物的比重和折射率.用三角坐标图表示出三元混合物的组成和恒比重、恒折射率的关系.2.测定了在25°和45°两个恒定温  相似文献   

7.
水中对硝基苯酚主要来源于化工、制药行业,它有致癌作用。人们已对它的测定方法进行了大量的研究,最早采用的测定方法是分光光度法,其检测限偏高;色谱法测定对硝基苯酚,操作繁琐,仪器昂贵,分析成本高。后来又发展了一种操作更方便的直接用于测定的电化学方法。本文旨在利用碳纳米管对对硝基苯酚的吸附性能,研究对硝基苯酚在多壁碳纳米管修饰电极上的电化学行为。  相似文献   

8.
本文以强场非对称波形离子迁移谱(FAIMS)芯片搭建的检测设备成功实现了对丙酮、苯酚和环己烷三种有机物及其混合物的检测。通过痕量气体发生器产生丙酮、苯酚和环己烷气体,利用气体流量计调节空气和有机物气体比例,模拟空气中不同浓度的有机挥发物,混合气体进入检测核心,得到相应的信号,并通过软件转化为对应的谱图;对比背景和含有机物气体的谱图,可确定有机物在谱图上的位置。该设备对不同浓度样品检测结果显示检测信号值与浓度成高度正相关。通过对正负模式下交变电场强度和补偿电压大小的调节,可以实现对混合物组分的分离检出。  相似文献   

9.
循环伏安法研究硝基药物的β-环糊精包含络合物   总被引:1,自引:0,他引:1  
本文用悬汞电极循环伏安法,研究了甲硝唑、氯霉素、对硝基苯酚和对硝基苯甲酸等药物的伏安性质,用“电流法”测定了药物与β-CD生成包络物的K_f值,并讨论其作用及稳定性。  相似文献   

10.
王京平 《色谱》2004,22(5):562-562
酚类已被列为优先控制的环境污染物,属高毒物质,其中硝基苯酚的3种异构体的分析测定备受关注。目前,已有采用分光光度法[1]、离子色谱法[2]、高效液相色谱法[3]测定的报道,但未查阅到采用气相色谱法对硝基苯酚的3种异构体同时分离和测定的系统研究。本文采用乙酸酐衍生化法对3种酚进行衍生,使之成为酯类进行分离[4],并采用邻苯二甲酸二甲酯作为内标物进行定量分析。1 实验部分1.1 主要仪器与试剂  美国Agilent6890气相色谱仪,氢火焰离子化检测器(FID),HPRev.A.08.01化学工作站;HP 5毛细管柱。邻、间、对硝基苯酚及乙酸酐、甲苯…  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

17.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

18.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
袁丽秋 《化学教育》2006,27(5):8-10
面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。  相似文献   

20.
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