Process for improving the conversion of oxazolidones to alkanolamines

摘要

There is provided a regeneration process for converting oxazolidones such as hydroxypropyloxazolidone (HPOZD) to alkanolamines such as diisopropanolamine (nIPA) and CO 2 . An amine stream containing HPOZD joins a stream that includes a caustic solution. The combined stream is passed to a tank where the caustic reacts with HPOZD to convert it to DIPA and CO 2 . The conversion of HPOZD to DIPA and CO 2 requires a ratio of at least 2 moles of hydroxide for each tnole of HPOZD in the solution. The conversion reaction is carried out in a reaction vessel at a temperature above 60°C. The reaction mixture is held in a feed tank for approximately 2 hours while being ccmstantly mixed. After the reaction is completed, the mixture is allowed to settle which results in the virtually complete separation of the amine phase (containing DIPA, and water) from the caustic phase. After an appropriate settling interval, a portion of the caustic phase is drawn from the reaction mixture as a waste/neutralization stream while the other portion of the caustic phase and a very small portion of the amine phase may be sent to a recycle tank for use in subsequent reaction steps. The majority of the amine phase is treated using ion exchange resins to remove excess cations from the amine and clean amine is returned to the amine system.