I am doing nitration of benzimidazolone by diluted nitric acid to get 5-nitro benzimidazolne. My problem is reaction not get to finish and seems 95% reaction completed while 4 to 5 % unreacted, so please any one can idea to get completion?.
Please note that i have also tried by MIX acid and also by con. Nitric acid
For how long time are you running your reaction?
Is everything dissolved?
To complete your reaction use the mixture of concetntrated HNO3 or KNO3 with H2SO4 because it is the most powerfull system. In this case do NOT use an excess of HNO3, but use an excess of H2SO4 as a reaction engine. See my profile with my broshure "Nitration". "Personally" for In benzimidazole use the next procedure.
In 240 mL of conc H2SO4 dissolve 59 g (0.5 mol) of benzimidazole with temperature not high than 200C at then at then add 32 g (0.5 mol) of 100% HNO3 or 51.5 g (0.5 mol) of dry KNO3 with the temperature not high than 25 0C with stirring. The temperature simultatiuosly have to rose to 50-52 0C. Stir the mixture (intesive stirring) for 4h, than add 1 kg of ice, add aq NH3 to pH = 7, Filtrate the precipitate, wash it with water and recrystallise from aq EtOH. Yield 90+%, purity 98+%. mp 204-205 0C
http://www.findpatent.ru/patent/66/664962.html
© FindPatent.ru - патентный поиск, 2012-2017
.findpatent.ru/patent/66/664962.html
check the percetage purity of Nitric acid and sulphuric check the probable isomer too acid.
- Badges
- Science topic
- Similar topics
- Chemistry
- Organic Chemistry