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 C 3 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 arectification 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 side stream, wherein step c) is carried out in an absorption column (12) comprising at least two cooling loops, a first cooling loop (14), wherein a high boiler fraction of the product gas mixture is condensed and a second cooling loop (16), wherein a low boiler fraction of the product gas mixture is condensed, wherein a portion of the absorbate A, which comprises the feed stream F (2), is removed from the absorption column (12) at a side take-off (20), the side take-off (20) being located at the first cooling loop (14) or at a height of the absorption column (12) between the first cooling loop (14) and the second cooling loop (16) and wherein a temperature (Tc) of the absorbate A in the second cooling loop is at least 56°C.
Abstract:
Verfahren zur Stabilisierung von Acrylverbindungen, wobei man eine flüssige Phase, welche mindestens eine Acrylverbindung aus der Gruppe Acrylsäure, Methacrylsäure und deren jeweiligen Estern enthält, mit mindestens einem Metall aus der Gruppe Kupfer, Mangan und Cer versetzt sowie mindestens einem Liganden aus der Gruppe bestehend aus a) Chinolinverbindungen der Formel (I), wobei die Symbole folgende Bedeutungen haben: X ist OH, NH 2 , O-C 1 -C 4 -Alkyl, vorzugsweise OCH 3 , O-C(O)-C 1 -C 4 -Alkyl, vorzugsweise O-C(O)-CH 3 , O-C(O)-C 2 H 5 oder O-C(O)-Phenyl; R 1 ist H, oder (C 1 -C 4 )-Alkyl, vorzugsweise Methyl; R 2 ist H, C 1 -C 4 -Alkyl, vorzugsweise Methyl, Cl, Br oder SO 3 H und R 3 ist H, Cl oder Br; sowie N-Oxiden von Verbindungen der Formel (I), b) 2,2'-Bis(2,3-dihydro-3-oxoindolyliden) und c) aliphatische y-zähnige Liganden mit y = 2-6, enthaltend mindestens zwei Stickstoffatome und y-2 weitere koordinierende Stickstoff- oder Heteroatome enthaltende aliphatische oder aromatische C 1 -C 4 Kohlenstoffbrücken verbunden sind.
Abstract:
Kontinuierliches Verfahren zur Herstellung von (Meth)acrylaten von C10-Alkoholgemischen durch Umsetzung von Rein-(Meth)acrylsäure mit einem Isomerengemisch von C 10 -Alkoholen aus 2-Propylheptanol als Hauptisomer und mindestens einem der C 10 -Alkohole 2-Propyl-4- methylhexanol, 2-Propyl-5-methylhexanol, 2-lsopropylheptanol, 2- lsopropyl-4-methylhexanol, 2- isopropyl-5-methylhexanol und/oder 2- Propyl-4,4-dimethylpentanol, sowie die Verwendung eines Diesters von Dicarbonsauren, die mit N-Oxyl-gruppenhaltigen Verbindungen verestert sind, als Polymerisationsinhibitoren in einem solchen Verfahren
Abstract:
The invention relates to a method for stabilising acrylic compounds, wherein a liquid phase, which contains at least one acrylic compound from the group acrylic acid, methacrylic acid and their respective esters, is mixed with at least one metal from the group copper, manganese and cerium and at least one ligand from the group consisting of a) quinoline compounds of formula (I), wherein the symbols have the following meanings: X is OH, NH 2 , O-C 1 -C 4 -alkyl, preferably OCH 3 , O-C(O)-C 1 -C 4 -alkyl, preferably O-C(O)-CH3, O-C(O)-C 2 H 5 or O-C(O)-phenyl; R 1 is H, or (C 1 -C 4 )-alkyl, preferably methyl; R 2 is H, C 1 -C 4 -alkyl, preferably methyl, Cl, Br or SO 3 H and R 3 is H, Cl or Br; and N-oxides of compounds of formula (I), b) 2,2'-bis(2,3-dihydro-3-oxoindolylides) and c) aliphatic y-dentate ligands where y = 2-6, containing at least two nitrogen atoms and y-2 further coordinating aliphatic or aromatic C 1 -C 4 carbon bridges containing nitrogen atoms or heteroatoms.
Abstract:
A continuous method for producing (meth)acrylates from C10 alcohol mixtures by reacting pure (meth)acrylic acid with an isomeric mixture of C 10 alcohols of 2-propylheptanol as 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 are esterified with N-oxyl group containing compounds, as polymerisation inhibitors in such a method.
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.