Abstract: The invention relates to a superabsorbent polymer that includes a (meth)acrylic acid made by a process that comprises the following process steps: a) (meth)acrylic acid is crystallized out from a mother liquor; b) crystallized (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 superabsorbent polymer according to the present invention includes an process to make (meth)acrylic acid, the apparatus suitable for implementing the process, and the use of the apparatus for the production of (meth)acrylic acid characterized 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, thereby providing an improved superabsorbent polymer.

Abstract: The invention relates to a superabsorbent polymer that includes a (meth)acrylic acid made by a process that comprises the following process steps: a) (meth)acrylic acid is crystallized out from a mother liquor; b) crystallized (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 superabsorbent polymer according to the present invention includes an process to make (meth)acrylic acid, the apparatus suitable for implementing the process, and the use of the apparatus for the production of (meth)acrylic acid characterized 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, thereby providing an improved superabsorbent polymer.

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 crystallized out from a mother liquor; b) crystallized (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 characterized 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: 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: The present invention relates to a process for the production of acrylic acid (AA) comprising the steps wherein: a) a 1st gas mixture comprising propylene, oxygen, an inert gas and steam is subjected to a 1st catalytic oxidation reaction stage thereby converting the propylene in the presence of a catalyst mainly into acrolein being contained in a 2nd gas mixture from said 1st catalytic oxidation reaction, b) said 2nd gas mixture from the 1st catalytic oxidation reaction stage is subjected to a 2nd catalytic oxidation reaction stage thereby converting the acrolein in the presence of a catalyst mainly into AA, being contained in a product gas, c) said product gas is subjected to a quench tower, wherein said AA is recovered as an aqueous solution comprising said AA being contained in the process water, wherein a process vent gas is obtained at the top of said quench tower, wherein, said 1st gas mixture has a steam/propylene ratio of >0.

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: The present invention relates to a process for the production of acrylic acid (AA) comprising the steps wherein: a) a 1st gas mixture comprising propylene, oxygen, an inert gas and steam is subjected to a 1st catalytic oxidation reaction stage thereby converting the propylene in the presence of a catalyst mainly into acrolein being contained in a 2nd gas mixture from said 1st catalytic oxidation reaction, b) said 2nd gas mixture from the 1st catalytic oxidation reaction stage is subjected to a 2nd catalytic oxidation reaction stage thereby converting the acrolein in the presence of a catalyst mainly into AA, being contained in a product gas, c) said product gas is subjected to a quench tower, wherein said AA is recovered as an aqueous solution comprising said AA being contained in the process water, wherein a process vent gas is obtained at the top of said quench tower, wherein, said 1st gas mixture has a steam/propylene ratio of >0.

Abstract: The invention relates to a process for the oxidation of unsaturated hydrocarbons, wherein an unsaturated hydrocarbon, an oxygen-containing oxidizing agent, a palladium complex as the catalyst containing a ligand of the formula (I) wherein R is a saturated, halogenated alkyl radical having from about 1 to about 20 carbon atoms, and optionally auxiliary substances in a liquid phase based on (?1) from about 10 to about 100 wt. % of a protic polar solvent and (?2) from 0 to about 90 wt. % of an aprotic polar solvent, the sum of components (?1) and (?2) being about 100 wt. %, at a temperature in a range from about 30 to about 300° C. under a pressure in a range from about 1 to about 200 bar, such that a liquid phase containing oxygen-containing hydrocarbons is obtained.

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.