Compositions for Improved Production of Acrylic Acid

Abstract

The present invention is directed to compositions which may undergo thermolysis to produce a higher purity acrylic acid product. In preferred embodiments of the present invention, the compositions comprise polypropiolactone and one or more active salts. The one or more active salts may catalyze thermolysis of the polypropiolactone so that the polymer depolymerizes into acrylic acid monomers. Certain concentrations of the one or more active salts result in higher purity acrylic acid products of thermolysis. In certain preferred embodiments, the one or more active salts include an acrylate group which may decompose under thermolysis to provide acrylic acid and thus decrease the concentration of undesirable contaminants in the acrylic acid product. In certain preferred embodiment, the one or more active salts comprise sodium acrylate.

1 . A composition comprising:
 a. polypropiolactone; and   b. one or more active salts for catalyzing thermolysis of the polypropiolactone when the composition undergoes thermolysis at thermolysis conditions;   wherein a portion of the active salt is residual from a polymerization reaction producing the polypropiolactone.   
     
     
         2 . The composition of  claim 1 , wherein the one or more active salts are chosen from a group including sodium carbonate and potassium carbonate. 
     
     
         3 . The composition of  claim 1 , wherein said composition has a polypropiolactone concentration of at least about 95% by weight. 
     
     
         4 . The composition of  claim 1 , wherein said composition has polypropiolactone concentration of at least about 98% by weight. 
     
     
         5 . The composition of  claim 1 , wherein said polypropiolactone has a number average molecular weight between about 750 g/mol and about 10,000 g/mol. 
     
     
         6 . The composition of  claim 1 , wherein said polypropiolactone has a number average molecular weight of greater than about 10,000 g/mol. 
     
     
         7 . The composition of  claim 1 , wherein said composition has a concentration of said one or more active salts of at least about 0.01 by weight % 
     
     
         8 . The composition of  claim 1 , wherein said composition has a concentration of said one or more active salts of at least about 1% by weight. 
     
     
         9 . The composition of  claim 1 , wherein said composition has a concentration of said one or more active salts less than about 10% by weight. 
     
     
         10 . The composition of  claim 1 , wherein said composition has one or more active salts chosen from the group including sodium acrylate, potassium acrylate, sodium carbonate, potassium carbonate, and tert-butyl ammonium acrylate. 
     
     
         11 . The composition of  claim 1 , wherein the composition further comprises phenothiazine. 
     
     
         12 . A composition comprising:
 a. polypropiolactone having with a concentration of at least about 95% by weight and a number average molecular weight between about 750 g/mol and about 10,000 g/mol; and   b. one or more active salts with a concentration of at least about 0.01% by weight for catalyzing thermolysis of said polypropiolactone when the composition undergoes thermolysis at thermolysis conditions.   
     
     
         13 . The composition of  claim 12 , wherein a portion of said one or more active salts is residual from a polymerization reaction producing said polypropiolactone. 
     
     
         14 . The composition of  claim 12 , wherein said composition has polypropiolactone concentration of at least about 98% by weight. 
     
     
         15 . The composition of  claim 12 , wherein said composition has a concentration of said one or more active salts less than about 10% by weight. 
     
     
         16 . The composition of  claim 12 , wherein said composition has one or more active salts chosen from the group including sodium acrylate, potassium acrylate, sodium carbonate, potassium carbonate, and tert-butyl ammonium acrylate. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . The composition of  claim 1 , wherein said one or more active salts are residual polymerization catalyst from polymerization of said polypropiolactone. 
     
     
         23 . The composition of  claim 12 , wherein said one or more active salts are residual polymerization catalyst from polymerization of said polypropiolactone. 
     
     
         24 . (canceled) 
     
     
         25 . The composition of  claim 1 , wherein the composition comprises β-propiolactone (BPL). 
     
     
         26 . The composition of  claim 12 , wherein the composition comprises β-propiolactone (BPL).