Process for removal of acrolein from acrylonitrile product streams
View Patent ↗Acrolein is removed from a process stream such as a process stream generated in the manufacture of acrylonitrile. The process includes reacting the acrolein with a compound containing a reactable thiol or hydroxyl moiety in the presence of an acid catalyst. The present process provides for a refined process stream that contains no more than 5 ppm by weight unreacted acrolein.
1. A method for removing acrolein from a process stream comprising
(a) providing a process stream comprising acrolein; and
(b) reacting said acrolein in the presence of an acid catalyst with a scavenger compound containing a reactable hydroxyl moiety selected from the group consisting of alcohols, diols, glycerol, polyols, phenols, hydroxyl acids, hydroxyl nitriles and hydroxyl esters having a solubility of at least 1% in the process stream to form an acrolein derivative in a refined process stream.
2. The method of claim 1 wherein said acid catalyst is a solid acid catalyst.
3. The method of claim 1 wherein said process stream further comprises said acid catalyst.
4. The method of claim 1 further comprising adding said acid catalyst to said process stream prior to said reaction step (b).
5. The method of claim 1 wherein said reaction step (b) is conducted at a pH of between 3.0 and 7.0.
6. The method of claim 4 wherein said acid catalyst is selected from the group consisting of glycolic acid and acetic acid.
7. The method claim 1 wherein said process stream further comprises water.
8. The method of claim 7 wherein said process stream includes 2.0% to 3.0% by weight water at commencement of said reaction step (b).
9. The method of claim 8 further comprising the step of reducing the water content of said process stream to no more than 0.5% water.
10. The method of claim 1 wherein said acrolein derivative is an acrolein acetal.
11. The method of claim 1 further comprising separating said acrolein derivative from said refined process stream.
12. The method of claim 11 comprising distillation of said refined process stream.
13. The method of claim 1 wherein said process stream further comprises acrylontirile.
14. The method of claim 1 wherein said reacting step is performed in the substantial absence of a cyanide compound.
15. The method of claim 1 wherein said process stream further comprises acrylic acid.
16. A method for removing acrolein from a process stream comprising
(a) providing a process stream comprising acrolein; and
(b) reacting said acrolein with a scavenger compound containing a reactable hydroxyl moiety selected from the group consisting of alcohols, diols, glycerol, polyols, phenols, hydroxyl acids, hydroxyl nitriles and hydroxyl esters having a solubility of at least 1% in the process stream at a pH of between 3.0 and 7.0 to form an acrolein derivative in a refined process stream.