Green and atom-economical processes for producing phenolic antioxidants
View Patent ↗Processes for producing 1,3,5-trimethyl-2,4,6-tris(3,5-dialkyl-4-hydroxybenzyl)benzene are provided, in particular such processes that utilize 2,6-di-tert-butylphenol, paraformaldehyde, a secondary amine, mesitylene, and acetic acid.
1. A process comprising:
combining in a container at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol and refluxing at about 100° C. to about 140° C. for at least about 2 hours,
adding mesitylene and a catalytic amount of an acid catalyst to the container, and yielding at least 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene having a purity of at least about 98%, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.
2. A process comprising:
combining at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol to yield a solution comprising at least 2,6-di-tert-butyl-4-acetoxymethylphenol,
combining at least the solution, mesitylene, and a catalytic amount of an acid catalyst, and
yielding at least 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.
3. The process according to claim 2 wherein the paraformaldehyde is in excess as to the 2,6-di-tert-butylphenol.
4. The process according to claim 3 further comprising recovering unreacted paraformaldehyde.
5. A process comprising:
combining at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol to yield at least 2,6-di-tert-butyl-4-acetoxymethylphenol,
isolating at least the 2,6-di-tert-butyl-4-acetoxymethylphenol as a solid or a melt,
dissolving at least the 2,6-di-tert-butyl-4-acetoxymethylphenol solid or melt in at least acetic acid to form a solution,
combining at least the solution, mesitylene, and a catalytic amount of an acid catalyst, and
yielding at least a 1,3,5-trimethyl-2,4,6-tris(3,5-tert-butyl-4-hydroxybenzyl)benzene, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.
6. A process comprising:
combining at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol to yield at least 2,6-di-tert-butyl-4-acetoxyrnethylphenol,
isolating at least the 2,6-di-tert-butyl-4-acetoxymethylphenol as a solid or a melt,
combining at least the 2,6-di-tert-butyl-4-acetoxymethylphenol, mesitylene, and a catalytic amount of an acid catalyst, and
yielding at least a 1,3,5-trimethyl-2,4,6-tris(3,5-tert-butyl-4-hydroxybenzyl)benzene, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.
7. A process comprising:
combining at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol to yield a solution comprising at least 2,6-di-tert-butyl-4-acetoxymethylphenol,
acidifying the solution,
combining at least the 2,6-di-tert-butyl-4-acetoxymethylphenol, mesitylene, and a catalytic amount of an acid catalyst, and
yielding at least a 1,3,5-trimethyl-2,4,6-tris(3,5-tert-butyl-4-hydroxybenzyl)benzene, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.
8. The process according to claim 1 , wherein the secondary amine comprises dimethylamine, diethylamine, methylethylamine, diisopropylamine, methylisoproplyamine, ethylisopropylamine, dipropylamine, methylproplyamine, ethylpropylamine, di-butylamine, methylbutylamine, ethylbutylamine, proplybutylamine, diphenylamine, phenylnaphthylamine, piperidine, or piperazine.
9. The process according to claim 1 , wherein the secondary amine comprises dimethylamine or diethylamine.
10. The process according to claim 1 , wherein the acid catalyst comprises an alkyl sulfonic acid, an aryl sulfonic acid, chloroacetic acid, trifluoroacetic acid, or sulfuric acid.
11. The process according to claim 1 , wherein the acid catalyst comprises sulfuric acid.
12. The process according to claim 1 , further comprising recovering unreacted acetic acid.
13. The process according to claim 1 , further comprising recovering unreacted acetic acid and repeating the process using the recovered acetic acid.
14. The process according to claim 5 , wherein
isolating at least the 2,6-di-tert-butyl-4-acetoxymethylphenol as a solid or a melt, is replaced with
isolating at least the 2,6-di-tert-butyl-4-acetoxymethylphenol as a solid or a melt and purifying the 2,6-di-tert-butyl-4-acetoxymethylphenol.
15. The process according to claim 14 , wherein the purifying of the 2,6-di-tert-butyl-4-acetoxymethylphenol comprises washing the 2,6-di-tert-butyl-4-acetoxymethylphenol with water a plurality of times, crystallizing the 2,6-di-tert-butyl-4-acetoxymethylphenol from the acetic acid, precipitating the 2,6-di-tert-butyl-4-acetoxymethylphenol from a hydrocarbon solvent.
16. The process according to claim 14 , wherein the purifying of the 2,6-di-tert-butyl-4-acetoxymethylphenol comprises crystallizing the 2,6-di-tert-butyl-4-acetoxymethylphenol from the acetic acid, and further comprising recovering the acetic acid and repeating the process using the recovered acetic acid with new batches of paraformaldehyde, secondary amine, and 2,6-di-tert-butylphenol.
17. The process according to claim 2 , further comprising recovering the acetic acid and repeating the process using the recovered acetic acid with new batches of paraformaldehyde, secondary amine, and 2,6-di-tert-butylphenol.
18. A process comprising combining at least acetic acid, paraformaldehyde, a secondary amine, and 2,6-di-tert-butylphenol to yield a solution comprising at least 2,6-di-tert-butyl-4-acetoxyinethylphenol, %, wherein said process is produced in the absence of a hydrocarbon solvent or a halohydrocarbon solvent.