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发明公开
CN110698327A 中低温煤焦油中2,4/2,5-混合二甲酚的深度分离方法 审中-实审

中低温煤焦油中2,4/2,5-混合二甲酚的深度分离方法
摘要：
本发明公开了一种中低温煤焦油中2,4/2,5-混合二甲酚的深度分离方法，采用烷基化→精馏→脱烷基化的联合工艺路线，在烷基化阶段，以2,4/2,5-混合二甲酚为底物，以异丁烯为烷基化试剂，以布朗斯特酸为催化剂，反应温度50～90℃，生成6-叔丁基-2,4-二甲酚和4-叔丁基-2,5-二甲酚；在脱烷基化阶段，以浓硫酸为催化剂，在150～180℃条件下对6-叔丁基-2,4-二甲酚和4-叔丁基-2,5-二甲酚进行脱烷基化反应。本发明的有益之处在于：(1)实现了深度分离，2,4-二甲酚和2,5-二甲酚的烷基化最低转化率分别达到了92.8％和93.2％，在脱烷基化阶段精馏后的2,4-二甲酚和2,5-二甲酚的最低纯度分别达到了99.2％和97.5％；(2)工艺简单、成本低，环境污染小；(3)可以联产具有高附加值的抗氧化剂6-叔丁基-2,4-二甲酚。
摘要（英）：

The invention discloses a method for deep separation of mixed 2,4/2,5-dimethylphenol in medium-low-temperature coal tar. The method is carried out by adopting a combined technical route from alkylation to distillation to dealkylation. In an alkylation stage, mixed 2,4/2,5-dimethylphenol is used as a substrate, isobutylene is used as an alkylation reagent, Bronst acid is used as a catalyst, the reaction temperature is in a range of 50-90 DEG C, and 6-tert-butyl-2,4-dimethylphenol and 4-tert-butyl-2,5-dimethylphenol are produced; and in a dealkylation stage, concentrated sulfuric acid is used asa catalyst, and the 6-tert-butyl-2,4-dimethylphenol and the 4-tert-butyl-2,5-dimethylphenol are subjected to dealkylation reactions at a temperature of 150-180 DEG C. The method has the following advantages: (1) deep separation is realized, the alkylation minimum conversion rate of 2,4-dimethylphenol and 2,5-dimethylphenol reaches 92.8% and 93.2% respectively, and the minimum purity of 2,4-dimethylphenol and 2,5-dimethylphenol after rectification in the dealkylation stage reaches 99.2% and 97.5% respectively; (2) the process is simple, cost is low, and environmental pollution is small; and (3) an antioxidant 6-tert-butyl-2,4-dimethylphenol with a high added value can be co-produced.

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