Adjunct for removal of aldehydes from chemical manufacturing production streams during distillative purification
AssigneeNalco/Exxon Energy Chemicals, L.P.
InventorsNatu R. Patel, Vincent E. Lewis, Margaret D. Enderson
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Abstract
A method for improving purification efficiency when distilling off aldehyde contaminants during chemical manufacturing processes by adding a substituted aromatic amine having electron donating group substituents prior to the distillation column. The method is particularly useful for removal of aldehydes such as acrolein, generated as a by-product of acrylonitrile manufacture. Preferred aromatic amines are 2-amino aniline, 3,4-dimethyl aniline and 4-ethyl aniline.
Claims11
A method for removing aldehydes from an aldehyde-contaminated acrylonitrile stream, wherein said contaminated stream is passed through a distillation column having an inlet end and an outlet end, comprising the steps of:
- a) making a solution of a substituted aromatic amine having electron-donating group substituents in a solvent containing a catalytic amount of a mineral acid;
- b) adding an effective aldehyde-scavenging amount of said solution of step a) to said stream at said inlet end of said column;
- c) scavenging aldehyde by forming of an aldehyde-aromatic amine Schiff base in said stream as said stream flows through said column, wherein said base remains within said column;
- and then,
- d) recovering a purified acrylonitrile stream from said outlet end at the top of said distillation column.
A method for removing acrolein from an acrolein-contaminated acrylonitrile stream, wherein said contaminated stream is passed through a distillation column having an inlet end and an outlet end, comprising the steps of:
- a) making a solution of a substituted aromatic amine having electron-donating group substituents in a solvent containing a catalytic amount of a mineral acid;
- b) adding an effective acrolein-scavenging amount of said solution of step a) to said stream at said inlet end of said column;
- c) scavenging acrolein by formation of an acrolein-aromatic amine Schiff base in said stream as said stream flows through said column, wherein said base remains within said column;
- and then,
- d) recovering a purified acrylonitrile stream from said outlet end at the top of said distillation column.
Dependencies are inferred from the claim text.