苯酚水溶性实验原理分析

纯净的苯酚是无色的晶体。常温下,苯酚在水中溶解度不大,当温度高于65℃时,则能与水互溶。当从溶液中析出苯酚或向苯酚钠溶液中通入CO2（或酸）时不能形成固态苯酚,需静置,采用分液的操作方法对混合体系进行分离。对其中的原因简单分析如下。     

Beta沸石上合成对叔丁基苯酚和2,4—二叔丁基苯酚

首次在三相条件下,在Ｂｅｔａ沸石催化剂上研究了苯酚与异丁烯烷基化合成对叔丁基苯酚和２,４－二叔丁基苯酚。通过对Ｈｂｅｔａ沸石高温焙烧和吡啶中毒试验研究了烷基化反应活性和选择性的变化规律;用ＮＨ３－ＴＰＤ和Ｐｙ－ＩＲ测定了试样的酸量和酸种类,结果表明Ｈｂｅｔａ沸石具有很好的烷基化活性,苯酚的转化率可达９２％,经１１２３Ｋ焙烧后苯酚转化率为８８％,对叔丁基苯酚和２,４－二叔丁基苯酚的选择性分别为７０～７５％和１４～２０％,中等强度的Ｂｒｎｓｔｅｄ酸是苯酚与异丁烯烷基化反应的活性中心。粘合剂含量低于３０％对烷基化活性基本无影响     

苯酚和氯苯酚的Pt／TiO2催化光解

在TiO_2和Pt/TiO_2催化作用下水溶液中苯酚、对氯苯酚、2,4-二氯苯酚和2,4,6-三氯苯酚均能发生光致降解(λ≥345nm)。在固定于反应器内壁的薄层Pt/TiO_2催化作用下,这些化合物的光致降解均呈现一级反应动力学;表观反应速率常数K_(ob)的相对大小为:苯酚<对氯苯酚<2,4-氯苯酚<2,4,6-三氯苯酚。少量H_2O_2(1.9×10~(-2)mol·L~(-1))能提高这些化合物的光解速率。光照1.0～5.0h后这些化合物的降解率大于97％,COD去除率大于95％。     

“苯酚”教学设计

1 教学目标 1.1 知识与技能 (1)了解苯酚的物理性质和用途; (2)掌握苯酚的结构和苯酚的酸性、与溴的反应等重要化学性质; (3)了解苯酚的用途,掌握苯酚的检验方法. 1.2 过程与方法 (1)运用实验探究的方法研究苯酚的性质; (2)培养学生实验操作、观察、分析能力,加深对分子中原子团相互影响的认识,培养学生辩证唯物主义观点; (3)逐渐树立学生透过现象看本质的化学学科思想.     

苯酚溶于碳酸钠吗？

苯酚溶于碳酸钠吗？万新军，宋明友（安徽省巢湖师范专科学校化学系２３８０００）苯酚俗称石炭酸，是一种弱酸（ＰＫａ＝１０），其酸性比碳酸（ＰＫａ＝６．３８）弱，所以苯酚不溶于ＮａＨＣＯ３。在可溶性的苯酚钠水溶液中通入ＣＯ２，苯酚会游离出来。那么，苯酚能否...     

鉴别苯酚应注意的问题

苯酚的定性鉴别受到溶剂和溶液酸碱性的影响.通过对不同有机溶剂中鉴别苯酚的对比实验,讨论溶液酸碱度对苯酚鉴别实验的干扰,对苯酚鉴别实验提出改进意见.     

胶束毛细管电泳在线推扫富集技术测定工业废水中痕量苯酚和硝基苯酚

利用胶束毛细管电泳在线推扫富集技术建立了测定工业废水中痕量苯酚、邻硝基苯酚和间硝基苯酚的方法。采用未涂层熔硅弹性石英毛细管(60cm×75μm,有效柱长52cm),选择20mmoL/L硼-砂80mmoL/L十二烷基硫酸钠(SDS)(pH9.45)为缓冲溶液,分离电压18kV,紫外检测波长214nm,在200s内可实现苯酚、邻硝基苯酚、间硝基苯酚的分离检测。在优化条件下,苯酚、邻硝基苯酚、间硝基苯酚的检出限分别为0.03、0.020、.02mg/L;相对标准偏差RSD(n=3)分别为3.42%、4.15%、3.48%;间硝基苯酚富集倍数可达1000倍。     

苯酚能否与硝酸直接作用生成三硝基苯酚?

酚类都很容易被氧化。硝酸是一种强氧化剂,苯酚如与硝酸直接作用则大部分被硝酸所氧化,生成的2,4,6-三硝基苯酚产量很低,     

溴水与苯酚反应产物的探讨

通过查阅文献和实验探究了苯酚的几种溴代产物在水、苯酚熔液和苯酚水溶液中的溶解性;从有机反应的理论角度探讨了苯酚溴代反应机理及产物的确证,指出苯酚与溴水反应的产物是2,4,6-三溴苯酚.     

五氯苯酚测定方法研究进展

介绍了目前国内五氯苯酚常用的分析方法,对每种分析方法的原理、操作条件、检测限、线性范围及应用对象作了较为详细的论述.指出吸光光度法操作简单,仪器比较普及,但五氯苯酚吸收带较宽,分辨率低,共存有机物影响较大,其应用受到限制.高效液相色谱法样品无需气化,也不需衍生化,是高沸点、热稳定性较差的五氯苯酚较理想的分析方法.乙酰衍生化、毛细管柱分离、电子俘获检测器检测是目前测定五氯苯酚最常用的气相色谱法.吹扫捕集技术、固相微萃取技术以及质谱检测技术在气相色谱分析中的应用有效提高了测定五氯苯酚的准确度和灵敏度.离子选择性电极法测五氯苯酚仍处于研究阶段.     

Disintegration test to measure lot-to-lot variations of vaginal tablets

Attempts were made to investigate the disintegration test for vaginal tablets. Disintegration tests were done for four different commercial vaginal tablets (three lots each) by the watch glass method and Japanese Pharmacopoeia (JP) disintegration method, and the resulting profiles were compared to those by the modified British Pharmacopoeia (BP) method on a point of lot-to-lot variation of the disintegration times. The disintegration time of every tablet by the modified BP method was longest, followed by the watch glass method, and finally by the JP disintegration method. The results for lot-to-lot differences in disintegration times by the modified BP method were similar to those by the watch glass method. However, such lot-to-lot differences as found by the modified BP method and watch glass method were not always observed by the JP disintegration method. It was concluded from these results that the modified BP method was most suitable for investigating lot-to-lot differences in the disintegration of vaginal tablets.     

Use of partial least-squares regression for multicomponent determinations based on kinetic spectrofluorimetric data. Simultaneous determination of canrenone and spironolactone in urine

A new spectrofluorimetric method for the simultaneous determination of canrenone and spironolactone in urine is proposed. The method is based on the different rates at which the two analytes react with hot sulfuric acid to form a trienone. The kinetic spectrofluorimetric data are processed by partial least-squares regression. The effects of sulfuric acid concentration and temperature on the system under study were also evaluated and the optimum values for carring out the reaction were 50% and 50 degrees C, respectively. The method was checked by analyzing urine samples that they contained both diuretics. The accuracy and the precision of the method were tested. The relative standard errors in the quantification of each analyte in all tested samples were 3.69 and 3.59%. The proposed method was validated by comparison with a high performance liquid chromatographic method for urine samples.     

Rapid determination of amino acids in neonatal blood samples based on derivatization with isobutyl chloroformate followed by solid-phase microextraction and gas chromatography/mass spectrometry

The purpose of this study was to develop a simple, rapid and sensitive analytical method for determination of amino acids in neonatal blood samples. The developed method involves the employment of derivatization and a solid-phase microextraction (SPME) technique together with gas chromatography/mass spectrometry (GC/MS). Amino acids in blood samples were derivatized by a mixture of isobutyl chloroformate, methanol and pyridine, and the N(O,S)-alkoxycarbonyl alkyl esters thus formed were headspace extracted by a SPME fiber. Finally, the extracted analytes on the fiber were desorbed and detected by GC/MS in electron impact (EI) mode. L-Valine, L-leucine, L-isoleucine, L-phenylanaline and L-tyrosine in blood samples were quantitatively analyzed by measurement of the corresponding N(O,S)-alkoxycarbonyl alkyl esters using an external standard method. SPME conditions were optimized, and the method was validated. The method was applied to diagnosis of neonatal phenylkenuria (PKU) and maple syrup urine disease (MSUD) by the analyses of five amino acids in blood samples. The results showed that the proposed method is a potentially powerful tool for simultaneous screening for neonatal PKU and MSUD.     

Evaluation of hybrid laser-cut and cast miniature fracture specimens

This paper presents a new hybrid laser-cutting method for producing fracture test specimens from thermosetting materials. The hybrid approach combines casting of a sheet of material with subsequent laser-cutting of the test specimens. The new approach was compared to the traditional casting method using a fracture toughness test. For this study, a compact version of the tapered double cantilever beam (cTDCB) was used as a specimen geometry for both manufacturing methods. The cTDCB specimen is crack length independent, and crack length investigations were performed to ensure the crack length independence of the cTDCB specimens. The specimens that were made by the hybrid laser-cut method were found to be comparable to the specimens obtained by the traditional casting method. Moreover, the laser-cut method provides a fast and accurate method to make a significant number of samples in a reasonable time. These tests show that the hybrid laser-cut method could be a good alternative to the traditional casting method.     

Amino acids and peptides. LV. Application of 2-adamantyl derivatives as protecting groups to the synthesis of peptide fragments related to Sulfolobus solifataricus ribonuclease. II.

Segment condensations were performed to construct peptide fragments related to Sulfolobus solifataricus Ribonuclease. At each condensation step, the new protecting groups were stable. The protected peptide fragments were treated with a low-high HF procedure to give the desired peptide fragments. These peptide fragments were also prepared by the solid-phase method, and the obtained peptides were compared with those obtained by the solution method. The peptide fragments obtained by the solution method were identical with those obtained by the solid-phase method on analytical HPLC, indicating that the new protecting groups could be easily removed by HF, and no racemization occurred during the synthesis of the protected peptides.     

Thermal desorption gas chromatography–mass spectrometry as an enhanced method for the quantification of polycyclic aromatic hydrocarbons from ambient air particulate matter

Polycyclic aromatic hydrocarbons (PAHs) from ambient air particulate matter (PM) were analysed by a two-step thermal desorption (TD) injection system integrated to a gas chromatograph–mass spectrometer (GC/MS). The operational variables of the TD method were optimised and the analytical expanded uncertainties were calculated to vary from 8% to 16% over the operative concentration range (40–4000 pg). The performance of the TD method was validated by the analysis of a standard reference material and by comparison of PAH concentrations in PM samples to those obtained by a conventional liquid extraction (LE) method. The TD method reported lower uncertainties than the LE method for the analysis of similar concentrations in air. The TD method also showed advantages for shorter sampling times in comparison to 24 h for source apportionment applications and for reducing losses of more reactive compounds such as benzo[a]pyrene.     

A comparative uncertainty study of the calibration of macrolide antibiotic reference standards using quantitative nuclear magnetic resonance and mass balance methods

This study introduces the general method of quantitative nuclear magnetic resonance (qNMR) for the calibration of reference standards of macrolide antibiotics. Several qNMR experimental conditions were optimized including delay, which is an important parameter of quantification. Three kinds of macrolide antibiotics were used to validate the accuracy of the qNMR method by comparison with the results obtained by the high performance liquid chromatography (HPLC) method. The purities of five common reference standards of macrolide antibiotics were measured by the ¹H qNMR method and the mass balance method, respectively. The analysis results of the two methods were compared. The qNMR is quick and simple to use. In a new medicine research and development process, qNMR provides a new and reliable method for purity analysis of the reference standard.     

Screening method for pesticides in air by gas chromatography/tandem mass spectrometry

A multiresidue method for determining more than 70 pesticides in air has been validated using a single injection with gas chromatography/tandem mass spectrometry (GC/MS/MS). The method validation considered both stages of sampling and analysis. The sampling method, based on active sampling using sorption in sorbent cartidges, was validated by generating standard atmospheres. Performance parameters of the method were evaluated, with a reduction in the limits of quantification by injecting a higher volume of sample extract, and increase of selectivity by the use of MS/MS detection mode. The method was based on solid-phase extraction, which permits a degree of automation. The best adsorbents were found to be Chromosorb 106 and Tenax TA. The retention capacity of these sampling sorbents allows up to 1440 L of air to be sampled without any breakthrough for most of the compounds. Data were generated for assessing the potential exposure of bystanders. The application of the method to the analysis of the air in urban locations near agricultural areas showed that pesticides were present in most of the samples.     

Aluminum sulphate hydrates

Three different calculation methods of deriving kinetic parameters (activation energy and preexponential factor) from dynamic TG data have been applied for the sulphate decomposition stage of the aluminum sulphate octadecahydrate. The constant rate experiments were carried out by Derivatograph and DuPont thermobalances. The three parameters estimation methods included a simple differential method, the classical Coats-Redfern and a new direct integral method. The fits of the curves obtained by these procedures were compared both graphically and numerically. It was found that the direct integral method gave the most satisfactory results. With the order type reaction models this method in each case produced the smallest residual deviation values and the best fitting curves compared to those obtained by the other two methods. The activation parameters calculated by the differential method were not acceptable at all, for the estimated curves were very far from the measured ones.     

Zr基载体负载Pd催化剂用于贫燃天然气汽车尾气净化

 采用共沉淀法制备了 ZrO2, Y0.1Zr0.9Ox, Ce0.1Zr0.9Ox 和 Al0.1Zr0.9Ox 系列 Zr 基载体, 并用 N2 吸附-脱附和 X 射线衍射对其进行了表征. 再以此为载体, 采用浸渍法制备了整体式负载 Pd 催化剂, 催化剂涂层的涂覆量为 180 g/L 左右, Pd 含量为 1.25%. 测定了催化剂上 Pd 的分散度. 在模拟的贫燃天然气汽车尾气中考察了催化剂的活性, 并在尾气中有或无 SO2 存在的条件下比较了催化剂活性的差异. 结果表明, Y3+, Ce4+ 或 Al3+ 改性载体负载的 Pd 催化剂的耐硫性能明显改善; 无论尾气中是否存在 SO2, 以 Y3+ 或 Al3+ 改性载体负载的 Pd 催化剂的活性均明显高于 ZrO2 负载体的 Pd 催化剂.