Frank G. answered 05/25/19
Master of Organic Chem, I can help you will all your OChem topics!
Simply put, vigorous conditions would be defined as high temperature and high pressure. Temps above 100 C and pressures above 4 atm, are generally considered the low end of vigorous conditions for chemical reactions. Temps above 200-300 C are not uncommon, and pressures of 100 atm are easily obtained in the lab and in manufacturing plants.