Distillation process for production of acrylic acid

1. A system for converting beta propiolactone to acrylic acid, comprising:

(a) a reaction zone comprising beta propiolactone, a solvent, and a polymerization catalyst,

wherein the reaction zone is a reactive distillation column configured to (i) operate at or above the pyrolysis temperature of poly(propiolactone), (ii) concurrently polymerize the beta propiolactone to poly(propiolactone) in the presence of the polymerization catalyst and thermally decompose the poly(propiolactone) to acrylic acid, and (iii) output a distillation stream comprising the solvent; and

(b) a return loop configured to return a portion of the acrylic acid to the reaction zone;

wherein the reaction zone includes a single reactor, which is the reactive distillation column; and

a nanofiltration membrane is located upstream of the reactive distillation column for catching catalyst and allowing the beta propiolactone and tetrahydrofuran to pass when the tetrahydrofuran is used as the solvent.

2. The system of claim 1 , wherein the reaction zone is further configured to output a portion of the acrylic acid.

3. A system for producing acrylic acid, comprising:

a beta propiolactone source;

a polymerization catalyst source; and

a reactor comprising:

at least one inlet to receive beta propiolactone in a solvent from the beta propiolactone source and a polymerization catalyst from the polymerization catalyst source,

at least one outlet to output an acrylic acid stream and a distillation stream comprising the solvent,

wherein the reactor is one pot configured to (i) polymerize the beta propiolactone to produce poly(propiolactone) in the presence of the polymerization catalyst at or above the pyrolysis temperature of poly(propiolactone), (ii) concurrently thermally decompose the poly(propiolactone) to produce acrylic acid in the one pot, (iii) output the acrylic acid stream, and (iv) output the distillation stream;

wherein the solvent comprises tetrahydrofuran and the system includes a nanofiltration membrane to catch the catalyst but allow the beta propiolactone and the tetrahydrofuran to pass through.

4. The system of claim 3 , wherein the polymerization catalyst is homogeneous.

5. The system of claim 3 , wherein at least one inlet in the reactor receives the polymerization catalyst in a second solvent from the polymerization catalyst source.

6. The system of claim 5 , wherein the reactor further comprises an outlet to output a second distillation stream comprising the second solvent, or a recycling stream comprising the polymerization catalyst, or any combinations thereof.

7. The system of claim 3 , wherein the at least one inlet to receive the beta propiolactone and the polymerization catalyst are separate inlets in the reactor.

8. The system of claim 3 , wherein the at least one outlet to output the acrylic acid stream and the distillation stream are separate outlets in the reactor.

9. The system of claim 3 , comprising a return loop configured to return a portion of the acrylic acid to the reaction zone.

10. The system of claim 3 , wherein the at least one outlet includes an outlet for the acrylic acid stream, an outlet for the distillation stream comprising the solvent, and an outlet for the catalyst.