Dehydroxylation of nitroalcohols to nitroalkanes
View Patent ↗The present invention provides a process for producing nitroalkanes by dehydroxylation of nitroalcohols. This provides an alternate reaction route for making nitroalkanes, such as 2-nitropropane and its derivatives.
1. A dehydroxylation process for preparing a nitroalkane from a nitroalcohol comprising:
(A) contacting the nitroalcohol with an iodine catalyst selected from hydroiodic acid and iodine, in a reaction zone, under hydrogen pressure; and
(B) heating the reaction zone and contents to a reaction temperature between 50° C. and 250° C. to form the nitroalkane.
2. The dehydroxylation process according to claim 1 , wherein said reaction temperature is maintained for a period of time up to 24 hours.
3. The dehydroxylation process according to claim 1 , wherein the iodine catalyst is hydroiodic acid and the reaction temperature is between 100° C. and 200° C.
4. The dehydroxylation process according to claim 3 , wherein the nitroalcohol is 2-nitro-2-methyl-1-propanol, the reaction temperature is between 100° C. and 160° C., and the nitroalkane produced is 2-methyl-2-nitropropane.
5. The dehydroxylation process according to claim 1 , wherein a metal complex catalyst is also present in the reaction zone and the reaction temperature is between 100° C. and 160° C.
6. The dehydroxylation process according to claim 5 , wherein the iodine catalyst is iodine.
7. The dehydroxylation process according to claim 5 , wherein the metal complex catalyst is of formula:
M(A) n (B) m (C) o (D) p
wherein n+m+o+p is between 4 and 6;
A, B, C, and D are independently neutral or charged, mono or polydentate ligands having as a binding moiety phosphorus, nitrogen, sulfur, oxygen, or halogen, and
M is Rh, Ru, Ir, Ni, or Co.
8. The dehydroxylation process according to claim 5 , wherein the metal complex catalyst is a rhodium metal complex catalyst.
9. The dehydroxylation process according to claim 5 , wherein the metal complex catalyst is Rh(PPh 3 ) 3 Cl.
10. The dehydroxylation process according to claim 6 , wherein the nitroalcohol is 2-nitro-2-methyl-1-propanol and the nitroalkane produced is 2-methyl-2-nitropropane.
11. The dehydroxylation process according to claim 1 , wherein the pressure is between 50 psi and 2000 psi.
12. The dehydroxylation process according to claim 1 , wherein the molar ratio of nitroalcohol to iodine catalyst is 1:10 to 100:1.
13. The dehydroxylation process according to claim 1 , wherein the reaction temperature is maintained for a period of time not less than 4 hours.
14. The dehydroxylation process according to claim 1 , wherein the reaction temperature is between 100° C. and 220° C.
15. The dehydroxylation process according to claim 1 , wherein the nitroalcohol is a C 1 -C 20 nitroalcohol.
16. The dehydroxylation process according to claim 1 , wherein the nitroalcohol is selected from the group consisting of nitroethanol, 1-nitropropanol, 2-nitropropanol, derivatives thereof, and combinations of any two or more thereof.
17. The dehydroxylation process according to claim 1 , wherein the nitroalcohol is 2-nitro-2-methyl-1-propanol and the nitroalkane is 2-methyl-2-nitro-propane.
18. A dehydroxylation process for preparing a nitroalkane from a nitropolyol comprising:
(A) contacting the nitropolyol with an iodine catalyst selected from hydroiodic acid and iodine, in a reaction zone, under hydrogen pressure;
(B) heating the reaction zone and contents to a reaction temperature between 50° C. and 250° C. to form a nitroalcohol; and
(C) continuing to heat the reaction zone and contents to form the nitroalkane.
19. The dehydroxylation process according to claim 18 , wherein the nitropolyol is 2-nitro-2-methyl-1,3-propandiol, the nitroalcohol is 2-nitro-2-methyl-1-propanol, and the nitroalkane is 2-methyl-2-nitropropane.
20. The dehydroxylation process according to claim 18 , wherein the iodine catalyst is hydroiodic acid and the reaction temperature is between 170° C. and 200° C.; or
the iodine catalyst is iodine, the reaction temperature is between 100° C. and 160° C., and a rhodium metal complex catalyst is also present in the reaction zone.