Allyl acetate purification
View Patent ↗A process for purifying allyl acetate is disclosed. An acetoxylation mixture is distilled at elevated pressure to remove propylene and generate a first bottoms mixture comprising allyl acetate, acetic acid, acrolein, allyl diacetate, and 3-acetoxypropionaldehyde. The first bottoms mixture is flash vaporized, and the resulting vapor is contacted with a solid acidic catalyst under conditions effective to decompose allyl diacetate and 3-acetoxypropionaldehyde. The flashed product, which comprises allyl acetate, acetic acid, and acrolein, is then distilled to remove acrolein and generate a second bottoms mixture comprising allyl acetate and acetic acid. The second bottoms mixture can be used to manufacture allyl alcohol.
1. A process for purifying allyl acetate, comprising:
(a) distilling an acetoxylation mixture comprising allyl acetate, acetic acid, and propylene at elevated pressure to remove propylene and generate a first bottoms mixture comprising allyl acetate, acetic acid, acrolein, allyl diacetate, and 3-acetoxypropionaldehyde;
(b) flash vaporizing the first bottoms mixture and contacting the resulting vapor with a solid acidic catalyst under conditions effective to decompose allyl diacetate and 3-acetoxypropionaldehyde and provide a flashed product comprising allyl acetate, acetic acid, and acrolein; and
(c) distilling the flashed product to remove acrolein and generate a second bottoms mixture comprising allyl acetate and acetic acid.
2. The process of claim 1 wherein propylene is removed at a pressure greater than 50 psia and at an overhead temperature greater than 10° C.
3. The process of claim 1 wherein the catalyst is selected from the group consisting of clays; mixed oxides; molecular sieves and zeolites; ion-exchange resins; heteropolyacids; inorganic oxides, sulfates, nitrates, phosphates, and halides; activated carbons; and mixtures thereof.
4. The process of claim 1 wherein steps (b) and (c) are performed at or about atmospheric pressure.
5. The process of claim 1 wherein the vapor and the solid acidic catalyst are contacted in step (b) at a temperature within the range of 60° C. to 200° C.
6. The process of claim 1 wherein acrolein is removed in step (c) at a maximum overhead temperature within the range of 50° C. to 70° C.
7. The process of claim 1 wherein the second bottoms mixture is hydrolyzed to produce allyl alcohol.
8. The process of claim 7 wherein the hydrolysis is accomplished by contacting the second bottoms mixture with an acidic ion-exchange resin.
9. The process of claim 1 wherein, in (b), the flash vaporized first bottoms mixture is contacted with the solid acidic catalyst at or about atmospheric pressure and at a temperature of from 140° C. to 190° C.
10. The process of claim 1 wherein the flashed product provided in (b) comprises about 10-50 wt. % allyl acetate, about 50-90 wt. % acetic acid, and about 0.01-2 wt. % acrolein.
11. The process of claim 1 wherein the flashed product generated in (c) comprises about 10-50 wt. % allyl acetate, and about 50-90 wt. % acetic acid.
12. A process for purifying allyl acetate, comprising:
(a) distilling an acetoxylation mixture comprising allyl acetate, acetic acid, and propylene at elevated pressure to remove propylene and generate a first bottoms mixture comprising allyl acetate, acetic acid, acrolein, allyl diacetate, and 3-acetoxypropionaldehyde;
(b) flash vaporizing the first bottoms mixture and contacting the resulting vapor with a solid acidic catalyst under conditions effective to decompose allyl diacetate and 3-acetoxypropionaldehyde and provide a flashed product comprising allyl acetate, acetic acid, and acrolein; and
(c) distilling the flashed product to remove acrolein and generate a second bottoms mixture comprising allyl acetate and acetic acid,
wherein propylene is removed at a pressure within the range of 100 to 500 psia, a reboiler temperature within the range of 180° C. to 230° C., and an overhead temperature within the range of 20° C. to 50° C.
13. The process of claim 12 wherein the catalyst is selected from the group consisting of clays; mixed oxides; molecular sieves and zeolites; ion-exchange resins; heteropolyacids; inorganic oxides, sulfates, nitrates, phosphates, and halides; activated carbons; and mixtures thereof.
14. The process of claim 12 wherein steps (b) and (c) are performed at or about atmospheric pressure.
15. The process of claim 12 wherein the vapor and the solid acidic catalyst are contacted in step (b) at a temperature within the range of 60° C. to 200° C.
16. The process of claim 12 wherein acrolein is removed in step (c) at a maximum overhead temperature within the range of 50° C. to 70° C.
17. The process of claim 12 wherein the second bottoms mixture is hydrolyzed to produce allyl alcohol.
18. The process of claim 17 wherein the hydrolysis is accomplished by contacting the second bottoms mixture with an acidic ion-exchange resin.