摘要
以二氧化氮/氧气为硝化剂,硝化4-溴联苯可以得到两种标题化合物的异构体。考察了二氧化氮用量、催化剂的类型、用量和反应温度对硝化产率和4-溴-4'-硝基联苯与4-溴-2'-硝基联苯异构体比例的影响。实验发现,在该体系中催化剂HBEA-25表现了较好的催化活性,提高了4-溴-4'-硝基联苯的选择性和硝化产率。当n(4-溴联苯)∶n(发烟硝酸)=1∶3,加入0.35 g催化剂HBEA-25,回流反应10 h,硝化产率可达到94.3%,4'-溴-4'-硝基联苯的选择性达到4.39。
Two nitro isomers of 4-bromobiphenyl were obtained in the nitration of 4-bromobiphenyl with nitrogen dioxide / molecular oxygen as nitrating reagent. The effects of amount of nitrogen dioxide and catalyst,various type of catalysts and reaction temperature on yield and isomer ratio of 4-bromo-4＇-nitrobiphenyl to 4-bromo-2＇-nitrobiphenyl were investigated. It was found that zeolite HBEA-25 both displayed better catalytic activities. Superior selectivity for production of 4-bromo-4＇-nitrobiphenyl and higher mono-nitration yield was obtained. When the reaction was conducted in nitrogen dioxide / molecular oxygen nitrating system,a optimization was as follow： n（ 4-bromobiphenyl） ∶ n（ nitric acid） = 1∶ 3,0. 35 g HBEA-25 was added,and reacted at reflux temperature for 10 h. The 4-bromo-4＇-nitrobiphenyl to 4-bromo-2＇-nitrobiphenyl ratio could reach 4. 39 in high yield of 94. 3%.
出处
《化学试剂》
CAS
北大核心
2015年第11期1034-1038,共5页
Chemical Reagents
