2-Acrylamide-2-Methylpropanesulfonic Acid CAS 60719-84-8

A preparation method of 2-acrylamido-2-methylpropanesulfonic acid is completed by the following steps:
1. First add 50 ml of acrylonitrile to the reaction kettle as the pre-reaction solution, turn on the stirrer, stir at a rotational speed of 120 to 160 r/min, and use the freezing solution to reduce the temperature in the reaction kettle to 2 to 6 °C;
2. After the temperature in the reaction kettle drops to 2～6℃, add acrylonitrile and fuming sulfuric acid into the reaction kettle at a constant speed respectively, the reaction residence time is 1～1.5h, when the reaction solution reaches the overflow of the 1# reaction kettle When the flow port, the overflow liquid flows into the reactor;
3. When the overflow liquid flows into the reaction kettle, the vaporized isobutene is passed into the reaction kettle at a constant speed, the reaction residence time is 2.5～3h, and the reaction temperature is 37～42℃, and then it is continuously overflowed into the sedimentation crystallization kettle for constant temperature cooling, After drying under reduced pressure by centrifugation, 900.5g of 2-acrylamido-2-methylpropanesulfonic acid crude product was obtained; the product purity was 97.7% (detected by liquid chromatography);
4. The crude product of 2-acrylamido-2-methylpropanesulfonic acid and 2700g of acetic acid were added to the recrystallization kettle, and the temperature of the recrystallization kettle was heated to 80°C from room temperature in 40min, and then cooled to 20°C at a uniform speed , incubated at 20°C for 1 h, and centrifuged to dry to obtain 767.2 g of 2-acrylamido-2-methylpropanesulfonic acid.
The water content of the acrylonitrile described in the second step is 0.02%; the free state SO3 content in the oleum described in the second step is 5%; the inflow rate of the acrylonitrile described in the second step is 169.26g/h; in the second step The inflow rate of the oleum is 24.5g/h; the inflow rate of the vaporized isobutene in step 3 is 24.5g/h.
The yield of this method is 85.2% (calculated as crude 2-acrylamido-2-methylpropanesulfonic acid), the product purity is 99.9% (detected by liquid chromatography), and the melting point is 184.1°C.