Abstract: The present invention provides an apparatus comprising a feed arranged below the middle of the apparatus, a quenching agent inlet arranged above the feed, an outlet arranged below the feed and a draw arranged above the quenching agent inlet, the apparatus having a region provided with one or more packing elements, wherein at least one means which ensures the formation of a liquid layer having a height of at least 1 cm is present between the quenching agent inlet and a packing element present between the quenching agent inlet and feed. The present invention also provides a process for preparing acrylic acid, which includes a step of oxidizing acrolein, wherein the reaction mixture obtained in this oxidation is contacted with water as quenching agent in an inventive apparatus, and a composition obtainable as bottom product in the process according to the invention, comprising acrylic acid and water.

Abstract: The invention relates to a device comprising a feed which is arranged below the center of the device, a quenching agent inlet which is arranged above the feed, an outlet which is arranged below the feed, and a discharge which is arranged above the quenching agent inlet, said device having a region provided with one or more packets between the quenching agent inlet and the feed. The device is characterized in that at least one means is provided between the quenching agent inlet and a packet provided between the quenching agent inlet and the feed, said means ensuring the formation of a liquid layer with a height of at least 1 cm.

Abstract: Method for producing acrylic acid by dehydration of a C3 hydroxycarboxylic acid, characterized in that dehydration is achieved by contacting, at a temperature of more than 150° C., the hydroxycarboxylic acid with a mixture which is liquid at this temperature and comprises at least one metal salt of a C3 hydroxycarboxylic acid, and water.

Abstract: Method for producing acrylic acid by dehydration of a C3 hydroxycarboxylic acid, characterized in that dehydration is achieved by contacting, at a temperature of more than 150° C., the hydroxycarboxylic acid with a mixture which is liquid at this temperature and comprises at least one metal salt of a C3 hydroxycarboxylic acid, and water.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: The present invention relates to a process for preparing unsaturated aldehydes or unsaturated carboxylic acids by heterogeneous catalytic gas phase oxidation of unsaturated or saturated hydrocarbons, comprising the process steps of: i) providing a gas mixture comprising a saturated hydrocarbon and catalytically dehydrogenating the saturated hydrocarbon in the gas phase to obtain a gas mixture comprising an unsaturated hydrocarbon in a dehydrogenation reactor having a dehydrogenation catalyst material; or ii) providing a gas mixture comprising oxygen and an unsaturated hydrocarbon; iii) catalytically oxidizing the unsaturated hydrocarbon obtained in process step i) or provided in process step ii) in the gas phase to obtain a gas mixture comprising an unsaturated aldehyde in a first oxidation reactor having a first oxidation catalyst material; wherein at least one of the reactors selected from the dehydrogenation reactor, the first oxidation reactor and the second oxidation reactor comprises at least one foam b

Abstract: The present invention relates to a process for the production of polymers, such as water-absorbing polymer structures, by radical polymerization of acrylic acid, whereby the acrylic acid has been obtained by a synthesis process which comprises as a process step the splitting of an organic material by means of an enzyme or at least one component of an enzyme. The invention also relates to the water-absorbing polymers obtainable by this process, water-absorbing polymers which are based to at least about 25 wt % upon partially neutralized acrylic acid, a composite, a process for the production of a composite, the composite obtainable by this production, the use of acrylic acid in the production of polymers, preferably in the production of water-absorbing polymer structures, a device for the production of acrylic acid, and a process for the production of acrylic acid.

Abstract: The present invention relates to a process for the production of polymers, such as water-absorbing polymer structures, by radical polymerization of acrylic acid, whereby the acrylic acid has been obtained by a synthesis process which comprises as a process step the splitting of an organic material by means of an enzyme or at least one component of an enzyme. The invention also relates to the water-absorbing polymers obtainable by this process, water-absorbing polymers which are based to at least about 25 wt % upon partially neutralized acrylic acid, a composite, a process for the production of a composite, the composite obtainable by this production, the use of acrylic acid in the production of polymers, preferably in the production of water-absorbing polymer structures, a device for the production of acrylic acid, and a process for the production of acrylic acid.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: The invention relates to a method for producing acrolein by dehydrating an aqueous glycerin phase in an acrolein reaction region, obtaining an aqueous acrolein reaction phase; at least partially separating the aqueous acrolein reaction phase into an acrolein-rich acrolein phase and an acrolein-poor residual phase comprising glycerin, water and various other residuals; and recirculating at least part of the residual phase into the acrolein reaction region. Additionally, removing at least one of the residuals, other than glycerin or water, from either of the glycerin phase or a mixture phase obtained by mixing the glycerol phase with the low-acrolein residue phase and feeding the resulting purified glycerin or mixture phase into the acrolein reaction region. The invention furthermore relates to a method for producing acrylic acid, water-absorbing polymer formations, compounds and hygiene articles, and to devices for carrying out those methods.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: The present invention relates to a method for purifying an unpurified phase, containing a target product, preferably (meth)acrylic acid, water, and at least one impurity differing from the target product and from water comprising: a) crystallizing the target product and water; b) separating the crystals from the mother liquor created in step a); c) melting at least part of the separated crystals to form a melt; and d) recycling at least part of said melt to step b). The invention further relates to a method for the production of a purified phase, containing a target product and water, a method for the production of a polymer based on (meth)acrylic acid, polymers that may be obtained by means of said method, chemical products, such as fibers or molded bodies, and the use of polymers.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer.

Abstract: The present invention relates to superabsorbent polymer comprising acrylic acid made by the process comprising the steps of heating an aqueous glycerine solution to form glycerine; transporting the glycerine to the dehydration reactor; dehydrating the glycerine to an acrolein-comprising dehydration product; gas phase oxidating of the acrolein-comprising dehydration product to obtain an acrylic acid-comprising monomer gas; bringing into contact of the monomer gas with a quench agent to obtain an acrylic acid-comprising quench phase; working-up the quench phase to obtain an acrylic acid-comprising monomer phase; and polymerizing the acrylic acid-comprising monomer phase; wherein a plurality of gas bubbles is generated and wherein the dehydration occurs at least partially in the liquid phase. The superabsorbent polymer has certain properties for biodegradability and sustainability. Further, at least about 25% of the acrylic acid is based on glycerine.

Abstract: Process for separating a dissolved complex catalyst of a metal of group 4, 5, 6, 7, 8, 9 or 10 of the Periodic Table of the Elements and/or any free organophosphorus ligand present from a nonaqueous hydroformylation reaction mixture which contains an aldehyde product and an organic solvent at least one membrane which is more permeable to the hydroformylation product than to the organophosphorus ligand, the separation being carried out under a carbon monoxide partial vapor pressure of more than 200 kPa.

Abstract: The invention relates to a process for the preparation of acrylic acid and a process for the preparation of polyacrylic acid comprising the process steps: (a1) preparation of 3-hydroxypropionic acid from a biological material to give a fluid, in particular aqueous, phase containing 3-hydroxypropionic acid; (a2) dehydration of the 3-hydroxypropionic acid to give a fluid, in particular aqueous, solution containing acrylic acid; (a3) purification of the solution containing acrylic acid by a suspension crystallization or a layer crystallization to give a purified phase; and corresponding devices for carrying out these processes, and acrylic acid and polyacrylates. The invention is distinguished in that acrylic acid and polyacrylates can thereby be prepared efficiently, inexpensively, and sustainably with simple means and with a high purity on the basis of regenerable raw materials.

Abstract: The invention relates to a method for producing acrolein, comprising the following steps: (a) dehydrating an aqueous glycerin phase G1 in an acrolein reaction region, obtaining an aqueous acrolein reaction phase; (b) at least partially separating the aqueous acrolein reaction phase into an acrolein-rich acrolein phase and an acrolein-poor (in comparison to the acrolein phase) residual phase R1, wherein the residual phase R1 comprises glycerin, water and various remainders from glycerin and water; (c) recycling at least a part of the residual phase R2 in step (a); wherein i) from a glycerin phase G2 comprising remainders that differ from glycerin and water, at least one of said remainders is separated and the thus obtained, purified glycerin phase G2 is immediately supplied to the acrolein reaction region, or ii) at least one remainder different from glycerin and water is separated out of a mixture phase M1 obtained by mixing a glycerin phase G2 with the acrolein-poor residual phase R1, and the thus obtained,

Abstract: The present invention relates to a process for preparing unsaturated aldehydes or unsaturated carboxylic acids by heterogeneous catalytic gas phase oxidation of unsaturated or saturated hydrocarbons, comprising the process steps of: i) providing a gas mixture comprising a saturated hydrocarbon and catalytically dehydrogenating the saturated hydrocarbon in the gas phase to obtain a gas mixture comprising an unsaturated hydrocarbon in a dehydrogenation reactor having a dehydrogenation catalyst material; or ii) providing a gas mixture comprising oxygen and an unsaturated hydrocarbon; iii) catalytically oxidizing the unsaturated hydrocarbon obtained in process step i) or provided in process step ii) in the gas phase to obtain a gas mixture comprising an unsaturated aldehyde in a first oxidation reactor having a first oxidation catalyst material; wherein at least one of the reactors selected from the dehydrogenation reactor, the first oxidation reactor and the second oxidation reactor comprises at least one foam b