Direct Colorimetric Detection of Hydrogen Peroxide Using 4-Nitrophenyl Boronic Acid or Its Pinacol Ester

A colorimetric method for the direct determination of hydrogen peroxide in aqueous solution is described. H2O2 stoichiometrically converts 4-nitrophenyl boronic acid or 4-nitrophenyl boronic acid pinacol ester into 4-nitrophenol, which can be quantified by measuring the absorption at 400 nm in neutral or basic media. The reactions proceed fast under basic conditions and complete in 2 minutes to at pH 11 and 80?C. The linear range for the colorimetric method extends beyond 1.0 to 40 μM H2O2, and the limit of detection is ~1.0 μM H2O2. This method offers a convenient and practical process for rapid determination of hydrogen peroxide in aqueous media. Compared to many other techniques in H2O2 detection, this process is a direct measurement of H2O2, and is relatively unaffected by the presence of various salts, metal ions and the chelator EDTA.

TiCl_4-Al体系中低价钛诱导下醛酮还原偶联成片呐醇的反应研究

以价廉易得的铝粉还原四氯化钛制得低价钛,将其用于醛酮还原偶联,合成了6种片呐醇,其中对称片呐醇4种,不对称片呐醇2种.采用分级结晶法分离得到苯甲醛片呐醇的内消旋体(meso)和外消旋体(d,l),利用波谱分析确定了其结构.通过对比实验着重讨论了反应条件对产物的影响.推断了反应机理。

4-(2-萘)苯硼酸频那醇酯的高效液相色谱分析方法

因硼原子存在空的P轨道,硼酸频那醇酯类化合物容易受到带孤对电子的亲核试剂的进攻而水解,难以保证化合物始终维持原有的分子状态。同时硼酸酯类化合物对热不稳定,用气相色谱(GC)测定难以得到准确结果。本文以4-(2-萘)苯硼酸频那醇酯为分析对象,用以下液相色谱条件进行分析:流动相为乙腈,色谱柱为Venusil XBP C184.6mm×50mm×5μm(3根串联),溶剂为四氢呋喃,柱温为40℃,流速为1.0mL·min^(-1),检测波长为260nm,进样量为5μL,总分析时间30min。分析结果显示,主峰保留时间为12.8min,主峰峰形良好,杂质分离度高,方法重现性良好。