NOVEL METHOD OF FILTERING 2-ACRYLAMIDO-2-METHYLPROPANE SULPHONIC ACID Russian patent published in 2024 - IPC C07C303/44 C07C309/15 B01D37/04 B01D24/12 

FIELD: technological processes.

SUBSTANCE: present invention relates to a method for continuous filtration of suspension of 2-acrylamido-2-methylpropane sulphonic acid crystals by means of a rotary pressure filter equipped with a drum, on the surface of which there are cells coated with a filter medium, wherein said drum rotates in a stationary concentric cylinder comprising at least three zones separated from each other, respectively, a filtration zone, a washing zone and an unloading zone, wherein each zone communicates with cells. Method involves the following steps a–d. At step a), suspension of 2-acrylamido-2-methylpropane sulphonic acid crystals is fed into the filtration zone and the said suspension is filtered in the cells until a filter cake is formed. At step b), a washing solution is fed into the washing zone and the filter cake formed in the cells is washed. Further, at step c), the washed filter cake is dried in the drying zone by gas injection and at step d) the washed filter cakes are unloaded from the cells in the unloading zone. Method is characterized by the fact that the depth of the cells coated with the filter medium is from 6 to 150 mm, pressure is applied at least in the filtration, washing and drying zones, wherein pressure differs from one zone to another and ranges from 1.5 to 7 bar in the filtration zone, from 3 to 7 bar in the washing zone and from 4 to 10 bar in the drying zone.

EFFECT: providing an improved continuous method of producing and increasing purity of 2-acrylamido-2-methylpropane sulphonic acid crystals.

10 cl, 2 dwg, 13 tbl, 5 ex