PROCESS FOR THE PURIFICATION OF ACRYLIC ACID
A process and an apparatus for the purification of a crude acrylic acid composition containing maleic anhydride as an impurity comprising the following steps: (a) carrying out at least one dynamic melt crystallization stage (14, 14a, 14b, 14c, 14d) with the crude acrylic acid composition to prepare...
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Format: | Patent |
Sprache: | eng ; hun |
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Zusammenfassung: | A process and an apparatus for the purification of a crude acrylic acid composition containing maleic anhydride as an impurity comprising the following steps:
(a) carrying out at least one dynamic melt crystallization stage (14, 14a, 14b, 14c, 14d) with the crude acrylic acid composition to prepare a first purified acrylic acid composition and a first residue containing at least 3.5 % by weight maleic anhydride,
(b) adding a solvent (26) to the first residue in an amount that the weight ratio of the solvent to the maleic anhydride is 0.3 or more to prepare a ratio-adjusted residue and
(c) carrying out at least one further dynamic melt crystallization stage and/ or at least one static melt crystallization stage (18, 18a, 18b) with the ratio-adjusted residue to prepare a second purified acrylic acid composition and a second residue. |
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