Purification Of Bio Based Acrylic Acid To Crude And Glacial Acrylic Acid

Abstract

Processes for the purification of bio-based acrylic acid to crude and glacial acrylic acid are provided. The bio-based acrylic acid is produced from hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. The purification includes some or all of the following processes: extraction, drying, distillation, and melt crystallization. The produced glacial or crude acrylic acid contains hydroxypropionic, hydroxypropionic acid derivatives, or mixtures thereof as an impurity.

What is claimed is: 
     
         1 . A composition of crude acrylic acid comprising between about 94 wt % and about 98 wt % acrylic acid, and wherein a portion of the remaining impurities in said composition of crude acrylic acid is hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof. 
     
     
         2 . The composition of  claim 1 , wherein the hydroxypropionic acid, hydroxypropionic acid derivatives, or mixtures thereof is lactic acid, lactic acid derivatives, or mixtures thereof. 
     
     
         3 . A crude acrylic acid composition produced by the steps comprising:
 a. Providing an aqueous solution of acrylic acid comprising: 1) acrylic acid; and 2) lactic acid, lactic acid derivatives, or mixtures thereof, and wherein said aqueous solution of acrylic acid is essentially free of maleic anhydride, furfural, and formic acid;   b. Extracting said aqueous solution of acrylic acid with a solvent to produce an extract;   c. Drying said extract to produce a dried extract;   d. Distilling said dried extract to produce a distilled acrylic acid composition; and   e. Determining the acrylic acid purity of said distilled acrylic acid composition, and if the purity is less than about 94 wt % acrylic acid, repeating said distilling step on the purified acrylic acid composition until a purity of about 94 wt % acrylic acid is achieved and said crude acrylic acid composition is produced.   
     
     
         4 . The composition of  claim 3 , wherein the aqueous solution of acrylic acid comprises from about 4 wt % to about 80 wt % acrylic acid. 
     
     
         5 . The composition of  claim 3 , wherein the aqueous solution of acrylic acid comprises from about 5 wt % to about 25 wt % acrylic acid. 
     
     
         6 . The composition of  claim 3 , wherein the aqueous solution of acrylic acid comprises from about 0.001 wt % to about 50 wt % lactic acid, lactic acid derivatives, or mixtures thereof. 
     
     
         7 . The composition of  claim 3 , wherein the aqueous solution of acrylic acid comprises from about 0.001 wt % to about 20 wt % lactic acid, lactic acid derivatives, or mixtures thereof. 
     
     
         8 . The composition of  claim 3 , wherein said solvent is selected from the group consisting of ethyl acetate, isobutyl acetate, methyl acetate, toluene, dimethyl phthalate, hexane, pentane, diphenyl ether, ethyl hexanoic acid, N-methylpyrrolidone, C6 to C10 paraffin fractions, and mixtures thereof. 
     
     
         9 . The composition of  claim 3 , wherein said drying is performed by azeotropic distillation. 
     
     
         10 . The composition of  claim 3 , wherein said drying is performed by distillation. 
     
     
         11 . The composition of  claim 3 , wherein said drying is performed by sorption. 
     
     
         12 . The composition of  claim 11 , wherein said sorption is performed on a solid powder selected from the group consisting of magnesium sulfate, sodium sulfate, calcium sulfate, molecular sieves, metal hydrides, reactive metals, and mixtures thereof. 
     
     
         13 . A crude acrylic acid composition produced by the steps comprising:
 a. Providing an aqueous solution of acrylic acid comprising: 1) acrylic acid; and 2) lactic acid, lactic acid derivatives, or mixtures thereof, and wherein said aqueous solution of acrylic acid is essentially free of maleic anhydride, furfural, and formic acid;   b. Extracting said aqueous solution of acrylic acid with a solvent to produce an extract;   c. Drying said extract to produce a dried extract;   d. Distilling said dried extract to produce a distilled acrylic acid composition;   e. Cooling said distilled acrylic acid composition to a temperature from about −21° C. to about 14° C. to produce crystals of acrylic acid;   f. Partially melting said crystals of acrylic acid to produce a liquid/solid mixture;   g. Decanting said liquid/solid mixture to produce a purified acrylic acid solid composition;   h. Fully melting said purified acrylic acid solid composition to produce a purified acrylic acid liquid composition; and   i. Determining the acrylic acid purity of said purified acrylic acid liquid composition, and if the purity is less than about 94 wt % acrylic acid, repeating said cooling, partially melting, decanting, and fully melting steps on the purified acrylic acid liquid composition until a purity of about 94 wt % acrylic acid is achieved and said crude acrylic acid composition is produced.   
     
     
         14 . The composition of  claim 13 , wherein the aqueous solution of acrylic acid comprises from about 4 wt % to about 80 wt % acrylic acid. 
     
     
         15 . The composition of  claim 13 , wherein the aqueous solution of acrylic acid comprises from about 5 wt % to about 25 wt % acrylic acid. 
     
     
         16 . The composition of  claim 13 , wherein the aqueous solution of acrylic acid comprises from about 0.001 wt % to about 50 wt % lactic acid, lactic acid derivatives, or mixtures thereof. 
     
     
         17 . The composition of  claim 13 , wherein the aqueous solution of acrylic acid comprises from about 0.001 wt % to about 20 wt % lactic acid, lactic acid derivatives, or mixtures thereof. 
     
     
         18 . The composition of  claim 13 , wherein said solvent is selected from the group consisting of ethyl acetate, isobutyl acetate, methyl acetate, toluene, dimethyl phthalate, hexane, pentane, diphenyl ether, ethyl hexanoic acid, N-methylpyrrolidone, C6 to C10 paraffin fractions, and mixtures thereof. 
     
     
         19 . The composition of  claim 13 , wherein said drying is performed by azeotropic distillation. 
     
     
         20 . The composition of  claim 13 , wherein said drying is performed by distillation. 
     
     
         21 . The composition of  claim 13 , wherein said drying is performed by sorption. 
     
     
         22 . The composition of  claim 21 , wherein said sorption is performed on a solid powder selected from the group consisting of magnesium sulfate, sodium sulfate, calcium sulfate, molecular sieves, metal hydrides, reactive metals, and mixtures thereof.