Process for the preparation of nitroalcohols
View Patent ↗A process of preparing a nitroalcohol, e.g., 2-nitro-2-methyl-1-propane, from a nitropolyol, e.g., 2-nitro-2-methyl-1,3-propanediol, the process comprising the step of contacting under hydrogenation conditions the nitropolyol with hydrogen, a hydrogenation catalyst and, optionally, a chelating agent.
1. A process of preparing a nitroalcohol from a nitropolyol, the process comprising the step of contacting at a temperature of 25-120° C. and a pressure of 300-1400 psi a nitropolyol with hydrogen and a hydrogenation catalyst, wherein the hydrogenation catalyst is Pd/C.
2. The process of claim 1 in which the hydrogenation catalyst is used in combination with a chelating agent.
3. The process of claim 2 in which the chelating agent is at least one of diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N,N′-bis(2-hydroxyethyl)ethylenediamine-N,N′-diacetic acid (HEEDA), N-2-hydroxyethyliminodiacetic acid (HEIDA) and nitrilotriacetic acid (NTA).
4. The process of claim 3 in which the amount of chelating agent used on a weight to weight basis with the catalyst metal is 1:1 to 1.5:1.
5. The process of claim 4 in which the nitropolyol is at least one of 2-nitro-2-methyl-1,3-propanediol and tris(hydroxymethyl)nitromethane.
6. A process of preparing a nitroalcohol from a nitroalkane, the process comprising the steps of:
A) contacting under alkaline conditions a nitroalkane, an aldehyde, and an alkaline catalyst to form a nitropolyol, and
B) contacting at a temperature of 25-120° C. and a pressure of 300-1400 psi the nitropolyol of step A with hydrogen, a hydrogenation catalyst and, optionally, a chelating agent, wherein the hydrogenation catalyst is Pd/C.
7. The process of claim 6 wherein the nitroalkane is nitromethane or nitroethane.
8. The process of claim 7 wherein the aldehyde is formaldehyde.
9. The process of claim 6 wherein the aldehyde is formaldehyde.
10. The process of claim 6 wherein the amount of alkaline catalyst is 0.01 to 10 mol %.
11. The process of claim 6 wherein the amount of alkaline catalyst is 0.2 to 5 mol %.
12. The process of claim 6 wherein the amount of hydrogenation catalyst is 1 to 20 mol %.
13. The process of claim 6 wherein the amount of hydrogenation catalyst is 2 to 5 mol %.
14. The process of claim 13 wherein the amount of alkaline catalyst is 0.2 to 5 mol %.
15. The process of claim 1 wherein the amount of hydrogenation catalyst is 1 to 20 mol %.
16. The process of claim 3 wherein the amount of hydrogenation catalyst is 1 to 20 mol %.