Process for production of acrylic acid
Provided are integrated processes for the conversion of beta propiolactone to acrylic acid. Systems for the production of acrylic acid are also provided.
1. A method for producing acrylic acid, comprising:
(a) providing a feedstock stream comprising beta propiolactone;
(b) directing the feedstock stream to a reaction zone;
(c) contacting the feedstock stream with a polymerization catalyst in the reaction zone;
(d) polymerizing at least a portion of the beta propiolactone to poly(propiolactone) in the reaction zone, wherein the temperature of the reaction zone is at or above the pyrolysis temperature of poly(propiolactone);
(e) thermally decomposing the poly(propiolactone) in the reaction zone to produce acrylic acid; and
(f) withdrawing an acrylic acid product stream comprising the acrylic acid from the reaction zone;
wherein steps (b) and (e) occur in the same reaction zone.
2. The method of claim 1 , further comprising directing a return loop comprising a portion of the acrylic acid product stream to the reaction zone.
3. The method of claim 2 , wherein the return loop of acrylic acid is combined with the feedstock stream.
4. The method of claim 1 , wherein the polymerization catalyst is a salt of a compound of formula:
wherein p is 0 to 9.
5. The method of claim 1 , wherein the polymerization catalyst is a salt of a compound of formula:
where p is from 0 to 9 and IV is a non-volatile moiety.
6. The method of claim 1 , wherein the polymerization catalyst is heterogeneous.
7. The method of claim 1 , wherein after removal of all acrylic acid product stream, the polymerization catalyst remains as a salt or melt.
8. The method of claim 7 , further comprising recycling the salt or melt to the reaction zone.
9. The method of claim 1 , wherein the feedstock stream contains or is combined with a high boiling solvent.
10. The method of claim 9 , further comprising withdrawing a recycling stream of the polymerization catalyst from the reaction zone.
11. The method of claim 1 , further comprising directing a return loop of a portion of the acrylic acid product stream to the reaction zone.
12. The method of claim 1 , wherein the feedstock stream is neat.