85-38-1Relevant articles and documents
Continuous flow nitration of salicylic acid
Kulkarni, Amol A.,Nivangune, Nayana T.,Kalyani, Vishwanath S.,Joshi, Ramesh A.,Joshi, Rohini R.
, p. 995 - 1000 (2008)
Continuous flow nitration of salicylic acid using HNO3/AcOH was studied in the SS316 tubular microreactor. At specific reaction conditions, complete conversion of the reactant was achieved in less than 7 min. It yielded only mononitro derivatives with a higher selectivity of 5-nitrosalicylic acid. Presence of the lower amount of acetic acid in the reaction mixture was seen to be detrimental, leading to precipitation of the desired product (5-nitrosalicylic acid). Reaction at higher temperatures yielded byproducts. The continuous mode operation using the system comprising the microdevices was demonstrated for 2 h with consistent composition at the outlet
Advanced Real-Time Process Analytics for Multistep Synthesis in Continuous Flow**
Sagmeister, Peter,Lebl, René,Castillo, Ismael,Rehrl, Jakob,Kruisz, Julia,Sipek, Martin,Horn, Martin,Sacher, Stephan,Cantillo, David,Williams, Jason D.,Kappe, C. Oliver
supporting information, p. 8139 - 8148 (2021/03/01)
In multistep continuous flow chemistry, studying complex reaction mixtures in real time is a significant challenge, but provides an opportunity to enhance reaction understanding and control. We report the integration of four complementary process analytical technology tools (NMR, UV/Vis, IR and UHPLC) in the multistep synthesis of an active pharmaceutical ingredient, mesalazine. This synthetic route exploits flow processing for nitration, high temperature hydrolysis and hydrogenation reactions, as well as three inline separations. Advanced data analysis models were developed (indirect hard modeling, deep learning and partial least squares regression), to quantify the desired products, intermediates and impurities in real time, at multiple points along the synthetic pathway. The capabilities of the system have been demonstrated by operating both steady state and dynamic experiments and represents a significant step forward in data-driven continuous flow synthesis.
Fast and efficient nitration of salicylic acid and some other aromatic compounds over H3PO4/TiO2-ZrO2 using nitric acid
Kalbasi, Roozbeh Javad,Massah, Ahmad Reza,Zamani, Farzad,Hamid, Javaherian Naghash
experimental part, p. 397 - 403 (2010/10/20)
TiO2-ZrO2 (1/1)-surf with Ti and Zr molar ratio of 1/1 was prepared with surfactant through a sol-gel method. The optimum experimental condition was investigated for nitration of salicylic acid. Then, a number of nitration reactions were carried out with a variety of aromatic compounds in the optimum condition. The 25 wt% H3PO4/TiO2-ZrO2 (1/1)-surf catalyst showed good selectivity and yield in a short time for the nitration of salicylic acid and some other aromatic compounds.