Abstract: The invention concerns a process for purification of an acidic monomer having a double bond, as well as a device for synthesis of an acidic monomer having a double bond, a process for producing an acidic monomer having a double bond, an acid monomer having a double bond and obtainable by this process, fibres, formed bodies, films, foams, superabsorbent polymers and other special polymers based on or containing this acidic monomer, the use of this acidic monomer in or for producing fibres, formed bodies, films, foams, superabsorbent polymers or other special polymers.

Abstract: The invention relates to a washing apparatus, including a First Region (1) to which a wash material (4) is supplied, a Second Region (2), in which the wash material (4) is washed, and a Third Region (3), in which the wash material (4) is melted and a flow resistance (6), which is provided between the Second Region (2) and the Third Region (3), a purification apparatus, a synthesis device, a method for purifying a wash material, and the use of a washing apparatus or a purification apparatus for purifying and then using the target product obtained by the purification.

Abstract: The present invention relates to processes for purifying a composition containing (meth)acrylic acid, at least one impurity and water, wherein the composition has a water content in the range of 0.55 to 90, based on the composition, to form a purified phase containing (meth)acrylic acid and at least one impurity, wherein, in the purified phase, the quantity of at least one impurity is less than 7% by weight, based on (meth)acrylic acid in the purified phase.

Abstract: A process for the continuous preparation of very highly concentrated hydrogen peroxide having a content of greater than 80 wt.%, especially over 98 wt.%, by suspension crystallization and after-treatment of the H2O2 crystals. The after-treatment takes the form of countercurrent washing in a hydraulic or mechanical washing column with a packed crystal bed. Hydrogen peroxide is disclosed having a concentration of from 99.9 to 100 wt.% and a content of TOC, nitrate, phosphate, nickel and tin of in each case less than 4 mg/l.

Abstract: The invention relates to a process for the purification of (meth)acrylic acid in a process stage that comprises the following process steps: a) (meth)acrylic acid is crystallised out from a mother liquor; b) crystallised (meth)acrylic acid is separated from the mother liquor; c) at least part of the separated (meth)acrylic acid crystals are melted; d) the melted part is at least partially recycled to the step a) or step b). The process according to the invention, the apparatus suitable for implementing the process, and the use of the apparatus according to the invention for the production of (meth)acrylic acid are characterised by a high purity of the thereby obtainable (meth)acrylic acid as well as by a high efficiency with regard to the achievable yield and necessary energy requirement.

Abstract: A process for the concentration of aqueous hydrogen peroxide by discontinuous crystallization. A cooling surface is arranged in a crystallizing vessel and first wetted with hydrogen peroxide and then cooled at a high cooling rate, whereupon seed crystals form. The cooling rate is at least 1 K/s, preferably from 10 to 30 K/s. When the vessel has been filled with H2O2 starting material, the latter crystallizes, starting from the seed crystals, and forms a crystal layer. When the mother liquor of lower H2O2 concentration has been discharged, there follows a sweating operation with a slow increase in temperature, as a result of which the H2O2 concentration in the crystal layer is increased further.

Abstract: A process for the continuous preparation of very highly concentrated hydrogen peroxide having a content of greater than 80 wt.%, especially over 98 wt.%, by suspension crystallization and after-treatment of the H2O2 crystals. The after-treatment takes the form of countercurrent washing in a hydraulic or mechanical washing column with a packed crystal bed. Hydrogen peroxide is disclosed having a concentration of from 99.9 to 100 wt.% and a content of TOC, nitrate, phosphate, nickel and tin of in each case less than 4 mg/l.

Abstract: A process for the concentration of aqueous hydrogen peroxide by discontinuous crystallization. A cooling surface is arranged in a crystallizing vessel and first wetted with hydrogen peroxide and then cooled at a high cooling rate, whereupon seed crystals form. The cooling rate is at least 1 K/s, preferably from 10 to 30 K/s. When the vessel has been filled with H2O2 starting material, the latter crystallizes, starting from the seed crystals, and forms a crystal layer. When the mother liquor of lower H2O2 concentration has been discharged, there follows a sweating operation with a slow increase in temperature, as a result of which the H2O2 concentration in the crystal layer is increased further.