Ammonia without water in form of anhydrous is reacted with propylene oxide for the isopropanolamines MIPA, DIPA, TIPA production. The reaction is exothermic and so the reactor temperature is maintained by water circulation. Three types of products namely monoisopropanolamine (MIPA) C3H9NO boiling point 159 oC at 1 atm, diisopropanolamine (DIPA) C6H15NO2 (249 oC at 1 atm) triisopropanolamine (TIPA) C9H21NO3 (306 oC at 1 atm) can be produced by varying the feed ratio. Ammonia and propylene oxide flow rates are altered by the composition control system to produce the desired compound based on market demand. When excess propylene oxide is fed to the reactor than TIPA is formed rather than rest of the two compounds. As per the chemical reactions are shown below, one-mole propylene oxide produces MIPA.
NH3 + C3H6O → C3H9NO (MIPA)
NH3 + 2C3H6O → C6H15NO2(DIPA)
NH3 + 3C3H6O → C9H21NO3(TIPA)
In batch reactors, the chemical reaction between propylene oxide and mono and di produce di and trialkanolamines respectively.
C3H9NO + C3H6O→ C6H15NO2
C6H15NO2+ C3H6O→ C9H21NO3
Process flowsheet of isopropanolamines MIPA, DIPA, TIPA production:
The raw material is heated and pressurized for the required reactor operating conditions. Isopropanolamines have high boiling points than the raw material this make separation process simple. By stripping, unreacted ammonia and propylene oxide are recycled. Each compound can be separated by respective distillation column based on the boiling points. To produce the desired product the second line of production helps to manufacture DIPA by reacting ammonia and MIPA similarly TIPA is formed by reaction MIPA, DIPA and ammonia obtained by separation columns. Vacuum systems are provided to the column to conduct the separation process at low temperatures.