Abstract: The invention relates to a method for the purification of acrylamido-2-methyl-2-propanesulphonic acid comprising the following successive steps: 1) preparation of a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals by distillation of an aqueous solution of acrylamido-2-methyl-2-propanesulphonic acid in order to obtain a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals, 2) isolation of the acrylamido-2-methyl-2-propanesulphonic acid crystals generally by solid/liquid separation from said suspension in order to isolate said acrylamido-2-methyl-2-propanesulphonic acid crystals, characterised in that the distillation step is carried out continuously and at a pressure below atmospheric pressure.

Abstract: The present invention relates to a water-soluble polymer obtained by polymerization of at least a 2-dimethylaminoethyl acrylate monomer and/or its salts, in presence of at least a tocopherol and/or its derivatives, or a tocotrienol and/or its derivatives, and its uses.

Abstract: The present invention relates to a polymer obtained at least from a quantity A of 2-acrylamido-2-methylpropane sulfonic acid, in acid and/or salified form, characterized in that the quantity A of 2-acrylamido-2-methylpropane sulfonic acid contains 250 to 20,000 ppm by weight of 2-methyl-2-propenyl-sulfonic acid, in acid and/or salified form. The present invention also relates to the use of this polymer as a flocculant, viscosity reducing agent, thickener, absorbent, friction reducing agent or plasticizer or superplasticizer, in particular in a field chosen from among oil and gas recovery, water treatment, sludge treatment, paper manufacture, construction, mining, cosmetic product formulation, detergent formulation, textile manufacture and agriculture.

Abstract: The invention relates to a novel sulfobetaine monomer and to a process for the preparation thereof, advantageously by reaction between a vinyl-amine compound and a vinyl-sulfonic acid compound, preferably in the presence of a solubilizing agent. The invention also relates to the (co)polymers obtained from this novel type of sulfobetaine monomer, and to the use thereof, for example as a flocculant, dispersing agent, thickening agent, absorbent agent or friction-reducing agent.

Abstract: The present invention relates to a water-soluble polymer obtained by polymerization of at least a 2-dimethylaminoethyl acrylate monomer and/or its salts, in presence of at least a tocopherol and/or its derivatives, or a tocotrienol and/or its derivatives, and its uses.

Abstract: A continuous process for filtering a suspension of 2-acrylamido-2-methylpropane sulfonic acid crystals by means of a rotary pressure filter equipped with a drum, a surface of which is provided with cells covered with a filter medium, the drum rotating within a fixed concentric cylinder comprising at least three zones sealed from each other, respectively a filtration zone, a washing zone and a discharge zone, each zone opening onto the cells.

Abstract: The invention relates to a method for the purification of acrylamido-2-methyl-2-propanesulphonic acid comprising the following successive steps: 1) preparation of a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals by distillation of an aqueous solution of acrylamido-2-methyl-2-propanesulphonic acid in order to obtain a suspension of acrylamido-2-methyl-2-propanesulphonic acid crystals, 2) isolation of the acrylamido-2-methyl-2-propanesulphonic acid crystals generally by solid/liquid separation from said suspension in order to isolate said acrylamido-2-methyl-2-propanesulphonic acid crystals, characterised in that the distillation step is carried out continuously and at a pressure below atmospheric pressure.