以邻甲酚和异丁烯为原料,采用自制的定向催化剂高选择性合成半受阻酚类抗氧剂中间体2-甲基-6-叔丁基苯酚.通过条件优化实验确定其最佳定向合成工艺为自制催化剂A为催化剂、m(催化剂A)∶m(邻甲酚)=0.25％、t=3 h、t=110 ℃、n(异丁烯)∶n(邻甲酚)=1.04;该条件下,2-甲基-6-叔丁基苯酚收率大于96.0％,选择性大于93.0％,纯度高于99.0％,熔程为25.0～28.0℃.IR和1 H NMR证实所合成目标产物2-甲基-6-叔丁基苯酚的化学结构与其理论结构相一致.以线性低密度聚乙烯(LLDPE)为研究对象,抗氧化性能测试结果表明2-甲基-6-叔丁基苯酚能较好地抑制LLDPE热氧化降解,且性能略优于全受阻酚类抗氧剂中间体2,6-二叔丁基苯酚.
Optimization of directional synthesis process and antioxidant properties for 2-tert-butyl-6-methylphenol
A semi-hindered phenolic antioxidant intermediate(2-tert-butyl-6-methylphenol)with high selectivity was synthesized using o-cresol and isobutylene as materials and the synthesized directional catalyst as catalyst.The optimal synthetic conditions were studied by conditional experiments and the optimal directional synthetic conditions were as follows:the synthesized directional catalyst A was catalyst,the mass ratio of catalyst A and o-cresol was 0.25％,the reaction time was 3 h,the reaction temperature was 110 ℃ and the mole ratio of isobutylene and o-cresol was 1.04.Under the conditions,the yield of 2-tert-butyl-6-methylphenol(melting point 25.0～28.0 ℃)can be up to 96.0％,the selectivity was above 93.0％and the purity was above 99.0％.The structure was confirmed by IR and1 H NMR.The antioxidant activity of 2-tert-butyl-6-methylphenol was evaluated for linear low-density polyethylene(LLDPE),and the results showed that 2-tert-butyl-6-methylphenol could well inhibit the oxidation of LLDPE during processing or thermal oxidation.The antioxidant activity of 2-tert-butyl-6-methylphenol was superior to 2,6-di-tert-butylphenol in LLDPE during processing or thermal oxidation.
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