间苯二胺选择性乙酰化合成间氨基乙酰苯胺

Synthesis of m-Aminoacetanilide by Selective Acetylation of m-Phenylenediamine

以间苯二胺为原料,盐酸(36%)为氨基保护剂,乙酸和乙酸酐混合为酰化剂,氯化钠为抑制剂,经选择性乙酰化反应合成染料中间体间氨基乙酰苯胺,通过FT-IR、1H NMR对产物结构进行了表征。考察了投料比、溶剂水用量、反应温度、反应时间、氯化钠用量对产品收率和纯度的影响,并得到最佳工艺条件:n(间苯二胺)∶n(盐酸)∶n(乙酸)∶n(乙酸酐)=1∶1∶1∶0.6、溶剂水用量为20 g、反应温度为70℃、反应时间为4 h、氯化钠用量为7g,母液可循环套用多次。通过对比发现乙酸和乙酸酐混合为酰化剂,既能减少废酸排放又能节省成本,抑制剂的加入可提高产品的收率及纯度。在此优化条件下间氨基乙酰苯胺收率为93.1%,纯度为98.5%。

Dye intermediate m-aminoacetanilide was synthesized by selective acetylation with m-phenylenediamine as raw material,hydrochloric acid(36%)as amino protective agent,acetic acid and acetic anhydride mixture as acylating agents,sodium chloride as inhibitor.Its structure was confirmed by FT-IR,1H NMR.The effect of feed ratio,solvent water dosage,reaction temperature,reaction time and sodium chloride dosage on the yield and purity of the product was investigated,and the optimal process conditions were determined as follows:n(m-phenylenediamine)∶n(hydrochloric acid)∶n(acetic acid)∶n(acetic anhydride)was 1∶1∶1∶0.6,solvent water dosage was 20 g,reaction temperature was 70℃,reaction time was 4 h,sodium chloride dosage was 7 g,and the mother liquor was recycled many times.By comparison,using acetic acid and acetic anhydride as acylation reagent could not only cut down the emission of waste acid,but also save costs,addition of inhibitors improved the yield and purity of the product.The yield and purity of m-aminolacetanilide were 93.1%and 98.5%when the synthesis was performed under the optimal conditions.