Processes for preparing 2,5-dichlorophenol
AssigneeMonsanto Technology LLC
InventorsKam-To Wan, John H. Ahn, John Wang, Don Probst
Life of this patent
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Abstract
Processes for producing 2,5-dichlorophenol and 3,6-dichloro-2-methoxybenzoic acid are described. Various processes for isomerizing 2,4-dichlorophenol over a zeolite catalyst to form 2,5-dichlorophenol are provided. Processes for preparing 2,5-dichlorophenol including hydroxylating 1,4-dichlorobenzene are also described. The present invention also relates to processes for producing 3,6-dichloro-2-methoxybenzoic acid.
Claims70
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol, wherein the zeolite catalyst has a SiO2/Al2O3 mole ratio of no greater than about 35:1.
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol and water with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol.
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol with a desilicated zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol, wherein the desilicated zeolite catalyst has a meso-macro pore volume (attributable to pores that have diameters greater than 20 Å up to 2500 Å) that is at least about 50%, at least about 75%, at least about 100%, at least about 125%, at least about 150%, at least about 175%, at least about 200%, at least about 225%, at least about 250%, at least about 275%, or at least about 300% greater than the meso-macro pore volume of the initial zeolite catalyst before desilication.
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol, wherein the zeolite catalyst has a meso-macro pore volume that is at least 0.15 cm3/g, at least 0.175 cm3/g, at least 0.2 cm3/g, at least 0.225 cm3/g, or at least 0.25 cm3/g.
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol and 3,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol.
A process for producing 2,5-dichlorophenol, the process comprising:
- contacting a feed comprising 2,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol;
- suspending contact of the feed comprising 2,4-dichlorophenol with the zeolite catalyst;
- and
- contacting the zeolite catalyst with steam at a temperature from about 250° C. to about 375° C. to rejuvenate the catalyst.
A process for producing 2,5-dichlorophenol, the process comprising:
- hydroxylating 1,4-dichlorobenzene with an oxidizing agent in the presence of a first zeolite catalyst in a hydroxylation zone to form a hydroxylation reaction product comprising 2,5-dichlorophenol and 2,4-dichlorophenol;
- separating at least a portion of the 2,4-dichlorophenol from the hydroxylation reaction product to form a fraction comprising 2,4-dichlorophenol;
- and
- contacting the fraction comprising 2,4-dichlorophenol with a second zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol.
A process for producing 3,6-dichloro-2-methoxybenzoic acid comprising carboxylating at least a portion of the 2,5-dichlorophenol prepared in accordance with any one of claims of the preceding claims to produce 2-hydroxy-3,6-dichlorobenzoic acid and methylating the 2-hydroxy-3,6-dichlorobenzoic acid to 3,6-dichloro-2-methoxybenzoic acid.
Dependencies are inferred from the claim text.