2-Nitro-N-(2-hydroxyethyl) aniline (HC Yellow 2) is a widely used dye and intermediate for hair coloring, textile dyeing, and printing. Therefore, investigating an efficient synthesis of HC Yellow 2 is of academic and practical importance. The reaction proceeds through nucleophilic aromatic substitution (SNAr) reaction between ethanolamine and nitro-substituted aryl halides (2-chloronitrobenzene or 2-bromonitrobenzene), promoted by potassium carbonate or catalyzed by copper(I) chloride. Literature-reported conditions using potassium carbonate at 160 °C may lead to product decomposition. At the same time, the copper-catalyzed method has low efficiency and safety concerns related to heavy-metal catalysts. In this study, we investigated and optimized the reaction conditions for the synthesis of HC Yellow 2 dye by comparing different substrates, potassium carbonate loadings, and catalysts. The effects of these conditions on product yield were evaluated. The results showed that 1 equiv. of potassium carbonate at 80 °C provided the best performance, and an isolated yield of 86.3% was obtained. Copper(I) chloride and zinc acetate catalysis were relatively inefficient by comparison. Based on the above results, proper control of both the base loading and the reaction temperature is essential to prevent product decomposition and achieve high yields of HC Yellow 2.

Yiqiu Shen. Optimization of Reaction Conditions for the Synthesis of HC Yellow 2 Dye. Academic Journal of Materials & Chemistry (2026), Vol. 7, Issue 1: 102-107. https://doi.org/10.25236/AJMC.2026.070114.

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