一种自制染料及其在酸碱滴定中的应用实验

A homemade dye and its application in acid-base titration

酸碱指示剂是一类常用的化学试剂,目前主要有硝基酚类、酚酞类、磺代酚酞类、偶氮化合物类等类型。实验设计合成了一种苯并噻唑类偶氮染料,并就其用于酸碱滴定指示剂的可行性进行分析,结果表明染料的耐酸碱性能较好,在不同pH值溶剂中的摩尔吸光系数和最大吸收波长以酸碱为分界线出现明显区域差异,在酸性环境中显示黄色,碱性环境中显示红色,能溶于N,N-二甲基甲酰胺、甲醇、乙醇等溶剂,可用作酸碱指示剂。

Acid-base indicators are a kind of commonly used chemical reagents. At present, there are mainly nitrophenols, phenolphthalein, sulfophenolphthalein, azo compounds and other types. A benzothiazole azo dye was designed and synthesized, and its feasibility for acid-base titration indicator was analyzed. The results showed that the dye had better acid-base resistance. The molar absorptivity and maximum absorption wavelength of the dye in different pH solvents showed obvious regional differences with acid-base as the demarcation line, yellow in acid environment, red in alkaline environment, and soluble. It can be used as acid-base indicator in N, N-dimethylformamide, methanol, ethanol and other solvents.