Abstract: A process for production of acrylic acid includes preparing a product gas mixture by a catalytic gas-phase oxidation of a C3 precursor; cooling and contacting the cooled product gas mixture in an absorption column having at least two cooling loops in countercurrent with an absorbent to obtain an absorbate A, containing the absorbent and absorbed acrylic acid; condensing a high boiler fraction of the product gas mixture in a first cooling loop; condensing a low boiler fraction of the product gas mixture in a second cooling loop; maintaining a temperature of the absorbate A in the second cooling loop at a value of at least 56° C.; removing an acid water stream comprising glyoxal from the absorption column at a side take-off located above the second cooling loop; and removing a stream F of absorbate A from the absorption column at a side take-off, located at a height of the absorption column between the first cooling loop and the second cooling loop.

Abstract: The invention is related to a process for production of acrylic acid comprising the following steps: a) preparation of a product gas mixture by a catalytic gas-phase oxidation of at least one C3 precursor compound to acrylic acid, wherein acrylic acid is formed as a main product of the catalytic gas-phase oxidation and glyoxal is formed as a by-product and the product gas mixture comprises acrylic acid and glyoxal, b) cooling of the product gas mixture, c) contacting the product gas mixture in countercourrent with an absorbent, wherein an absorbate A, comprising the absorbent and absorbed acrylic acid, is formed, d) introducing a feed stream F (2) comprising at least part of the absorbate A into a rectification column comprising a rectifying section and a stripping section, e) enriching the absorbent in the stripping section and enriching acrylic acid in the rectifying section, f) withdrawing a stream C of crude acrylic acid comprising at least 90% by weight of acrylic acid out of the rectifying section as a

Abstract: A continuous process for preparing (meth)acrylates of C10-alcohol mixtures by reaction of glacial (meth)acrylic acid with an isomer mixture of C10-alcohols composed of 2-propylheptanol as the main isomer and at least one of the C10-alcohols 2-propyl-4-methylhexanol, 2-propyl-5-methylhexanol, 2-isopropylheptanol, 2-isopropyl-4-methylhexanol, 2-isopropyl-5-methylhexanol and/or 2-propyl-4,4-dimethylpentanol, and the use of a diester of dicarboxylic acids which have been esterified with N-oxyl-containing compounds as polymerization inhibitors in such a process.

Abstract: In a method of stabilizing acrylic compounds, a liquid phase containing at least one acrylic compound is mixed with at least one metal and at least one ligand. The acrylic compound can be acrylic acid, methacrylic acid, and their respective esters. The metal can be copper, manganese, and cerium. The ligand can be a quinoline compound of formula (I), an N-oxide of a compound of formula (I), 2,2?-bis(2,3-dihydro-3-oxoindolylidene), or an aliphatic y-dentate ligand with y being 2-6 and comprising at least two nitrogen atoms joined by aliphatic or aromatic C1-C4 bridges comprising y-2 further coordinating nitrogen atoms or heteroatoms: where X is OH, NH2, O—(C1-C4)-alkyl, O—C(O)—(C1-C4)-alkyl, or O—C(O)-phenyl; R1 is H, or (C1-C4)-alkyl; R2 is H, (C1-C4)-alkyl, Cl, Br, or SO3H; and R3 is H, Cl or Br.

Abstract: A continuous process for preparing (meth)acrylates of C10-alcohol mixtures by reaction of glacial (meth)acrylic acid with an isomer mixture of C10-alcohols composed of 2-propylheptanol as the main isomer and at least one of the C10-alcohols 2-propyl-4-methylhexanol, 2-propyl-5-methylhexanol, 2-isopropylheptanol, 2-isopropyl-4-methylhexanol, 2-isopropyl-5-methylhexanol and/or 2-propyl-4,4-dimethylpentanol, and the use of a diester of dicarboxylic acids which have been esterified with N-oxyl-containing compounds as polymerization inhibitors in such a process.

Abstract: A process for separating acrylic acid present as a main product and glyoxal present as a by-product in a product gas mixture of a partial gas phase oxidation of a C3 precursor compound, in which a liquid phase P is obtained, which consists of acrylic acid to an extent of at least 70% of its weight and, based on the molar amount of acrylic acid present therein, comprises at least 200 molar ppm of glyoxal, in which the glyoxal is separated from the acrylic acid in the liquid phase P by crystallization.

Abstract: A process for inhibiting polymerization of (meth)acrylic acid and/or (meth)acrylic esters by introducing an oxygenous gas into the (meth)acrylic acid and/or the (meth)acrylic ester, in which the (meth)acrylic acid and/or the (meth)acrylic ester has a degree of purity of at least 95% and is in the liquid state.

Abstract: A process for transferring heat to a liquid mixture comprising at least one (meth)acrylic monomer in an indirect heat exchanger, wherein a quaternary ammonium salt, a tertiary amine or a salt thereof with a Brønsted acid is added to the liquid mixture to reduce fouling.

Abstract: A separating column containing a sequence of mass transfer trays that are supported by at least one covered double-T support and/or covered U-shaped support.

Abstract: In process for cleaning tray columns which are used for the purposes of rectifiying liquids comprising (meth)acrylic compounds, a basic liquid is conveyed downward through the tray column and a gas is passed through the column in countercurrent to the basic liquid at an average gas phase differential pressure over all trays of at least 0.5 mbar/tray.

Abstract: The invention describes a process for the preparation of novel surfactant alcohols and surfactant alcohol ethers by derivatization of olefins having from about 10 to 20 carbon atoms or of mixtures of such olefins to give alkanols, and optional subsequent alkoxylation, which comprises subjecting a C4-olefin mixture to metathesis, dimerizing the resulting olefins, and then derivatizing them to give surfactant alcohols, and optionally alkoxylating said alcohols. The olefin mixture obtained in the dimerization has a high proportion of branched components and less than 10% by weight of compounds which contain a vinylidene group. invention further describes the use of the surfactant alcohols and surfactant alcohol ethers to give surfactants by glycosylation or polyglycosylation, sulfation or phosphation.

Abstract: Process for stabilizing polymerizable compounds to polymerization during working-up, storage and/or transport, in which at least one free radical scavenger which contains at least two glycine units is used, with the proviso that the free radical scavenger is not selected from ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), trans-1,2-cyclohexanediaminetetraacetic acid (CYDTA) and the alkali metal and alkaline earth metal salts thereof.

Abstract: (Meth)acrylic monomers are separated by a thermal separation process by ascending at least one ascending gaseous stream in a separating column containing a sequence of mass transfer trays and a liquid stream that contains dissolved polymerization inhibitor which descends in the separating column, and in at least one of the streams being (meth)acrylic monomers; and spraying the inner surface of the separating column with the descending liquid stream that contains the dissolved polymerization inhibitor, and the separating column having internals, certain areas of which are shadow regions of the sprayed descending liquid stream; and which shadow regions are equipped by covering means which prevent contact of the shadow regions with (meth)acrylic monomers and consequently undesired polymerization of monomer.

Abstract: A process for preparing and/or working up mixtures by (meth)acrylic acid and/or (meth)acrylic ester in the presence of at least one polymerization inhibitor and at least one oxygenous gas, which comprises metering in at least part of the oxygenous gas at an exit rate of at least 50 mm/s.

Abstract: The invention relates to a hydrodynamic machine for transmitting torque. Said machine is equipped with the following features: a rotor-blade wheel (2); a stator-blade wheel (3); when viewed in a cylindrical cut, the blades (2.1, 3.1) are embodied and disposed as follows: they extend in planes which are inclined towards the axis (1.1) of the machine; they are substantially aligned relative to one another; they are angled with the purpose of forming a tip (2.6, 3.6). In order to reduce losses due to shock and to enhance efficiency, at least the flow areas of the edge of the blades are angled on both sides, when viewed in a cylindrical cut, so that the tip is located between the lateral limiting surfaces (2.3, 2.4. 3.3, 3.4) of the corresponding blade.

Abstract: Polycationic condensates obtainable by condensing

Abstract: Copolymers of hydroxyalkyl vinyl ethers are obtainable by cationic or free radical copolymerization of(a) from 99 to 1% by weight of a hydroxyalkyl vinyl ether,(b) from 1 to 99% by weight of an adduct of a C.sub.2 -C.sub.4 -alkylene oxide with a hydroxyalkyl vinyl ether and(c) from 0 to 98% by weight of other copolymerizable monomers,and the stated copolymer and hydroxyalkyl vinyl ethers polymerized by cationic or free radical polymerization, which contain the monomers (a) or (b) as sole monomers or as a mixture with other copolymerizable monomers in the form of polymerized units, are used as additives for detergents and cleaning agents in amounts of from 0.1 to 50% by weight.

Abstract: Soluble polyacetals containing acetaldehyde acetal units are obtainable by cationically initiated addition polymerization of(a) compounds containing at least 3 hydroxyl groups, and(b) divinyl ethers containing terminal vinyl ether groups, or mixtures of such divinyl ethers and monovinyl ethers, in the presence or absence of(c) dihydroxy compounds and/or monohydroxy compounds, and are useful as admixture in phosphate-reduced and phosphate-free detergents and cleaners and as dispersant for finely divided minerals.

Abstract: A magnetic recording medium comprises a nonmagnetic substrate and at least one ferromagnetic metal layer applied thereon and a protective layer formed on this metal layer and consisting of a compound which consists of an unfluorinated or partially fluorinated alkyl radical and a disulfide, hydroxyl or keto group.

Abstract: Polyacetals useful as reduced-phosphate or phosphate-free detergent and cleaner additives are obtainable by cationically initiated polyaddition of(a) divinyl ethers and(b) dihydroxy compounds and also, optionally,(c) monohydroxy compoundsand have K values of from 8 to 100.