Process for the preparation of formic acid

摘要

The invention relates to a process for the discontinuous preparation of concentrated formic acid by reaction of sodium formate with concentrated sulphuric acid in the presence of formic acid in a reactor at temperatures in the range from about 30 to 45 DEG C, separation by distillation under vacuum of the formic acid from the sodium sulphate formed and condensation of the formic acid vapours. The process is characterised in that the reaction is carried out at a pressure in the range from 30 to 70 mbar, simultaneously evaporating some of the formic acid by the liberated heat of reaction, then evaporating essentially all of the remaining formic acid by supply of heat to the reactor contents and then releasing the vacuum and mechanically discharging the sodium sulphate from the reactor. The process is characterised by a low consumption of external heat. <IMAGE>