负载型杂多酸催化下N2O5对甲苯的选择性硝化

用负载型杂多酸为催化剂,N2O5为硝化剂的新型硝化体系,对甲苯的硝化反应进行研究. 分别考察了杂多酸类型、载体种类、杂多酸负载量及催化剂循环使用次数等因素对硝化反应的影响. 结果证明,负载型杂多酸能显著提高N2O5的硝化能力;催化剂回收后可直接重复使用,甲苯硝化反应得率为34%,对位选择性达到58.9%,表明N2O5是一种具有应用前景的硝化试剂.

Supported Heteropolyacids Assisted Selective Nitration of Toluene with N2O5

Toluene nitration was carried out with supported heteropolyacids as catalysts and N2O5 as nitrating agent. Many factors were investigated, including the type of heteropolyacid and carrier, loading of heteropolyacid, and recycle times of the catalyst. Results shows that the nitration with N2O5 is an acid catalyzed reaction, and the supported heteropolyacids can highly enhance the nitration ability of N2O5; the catalysts can be directly reused after recycle, and their activity is not obviously decreased. Under the optimum conditions, the yield of nitration was 34%, and the para-selectivity was up to 58. 9%, which indicated that N2O5 is a prospective nitration agent, and the process meets the environmental protection requirements.