Process for downstream recovery of nitroalkane using dividing wall column
View Patent ↗Disclosed are a process and apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. Energy and capital costs may be reduced by using a dividing wall column.
1. A process for synthesizing at least one nitroalkane, the process comprising:
reacting in a reactor a hydrocarbon feedstock with aqueous nitric acid, such that a product stream is produced;
separating the product stream into at least an oil phase and an aqueous phase;
removing substantially all organic acids from the oil phase;
thereafter, distilling the oil phase in a dividing wall column, to recover at least a top product, a middle product, and a bottom product; and
recovering the at least one nitroalkane from the middle product.
2. A process according to claim 1 , further comprising returning the organic acids to the reactor.
3. A process according to claim 2 , further comprising recovering nitromethane from the top product, wherein the organic acids comprise acetic acid.
4. A process according to claim 1 , wherein the dividing wall column comprises a condenser and a reboiler.
5. A process according to claim 4 , wherein the condenser is operated at a temperature between 20 and 80 degrees Celsius.
6. A process according to claim 4 , wherein the reboiler is operated at a temperature between 75 and 85 degrees Celsius.
7. A process according to claim 1 , wherein the dividing wall column is operated at a vapor split ratio of about 0.5:0.5.
8. A process according to claim 1 , wherein the dividing wall column is operated at a liquid split ratio of about 0.37:0.63.
9. A process according to claim 1 , wherein the dividing wall column is operated at a liquid split ratio of about 0.46:0.54.
10. A process according to claim 1 , wherein the dividing wall column is operated at a liquid split ratio of about 0.35:0.65.
11. A process according to claim 1 , wherein the at least one nitroalkane is 2-nitropropane.
12. A process according to claim 11 , further comprising:
distilling the bottom product to recover at least one additional nitroalkane.
13. A process according to claim 12 , wherein the at least one additional nitroalkane is 1-nitropropane.
14. A process for nitroalkane recovery, the process comprising:
separating a product stream from a nitroparaffin nitration process into at least an oil phase and an aqueous phase;
distilling the oil phase in a dividing wall column, to recover at least a top product, a middle product, and a bottom product;
recovering at least a first nitroalkane from the middle product; and
recovering at least a second nitroalkane from the bottom product.
15. A process according to claim 14 , wherein the first nitroalkane is 2-nitropropane.
16. A process according to claim 15 , wherein the second nitroalkane is 1-nitropropane.