Processes for preparing 2,5-dichlorophenol
AssigneeMonsanto Technology LLC
InventorsKam-To Wan, John H. Ahn, John Wang, Don Probst
Life of this patent
Estimating the term…
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.
Claims42
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% greater than the meso-macro pore volume of the initial zeolite catalyst before desilication;
- or
- 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 about 0.15 cm3/g.
A process for producing 3,6-dichloro-2-methoxybenzoic acid 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;
- carboxylating at least a portion of the 2,5-dichlorophenol to produce 2-hydroxy-3,6-dichlorobenzoic acid;
- and
- methylating the 2-hydroxy-3,6-dichlorobenzoic acid to 3,6-dichloro-2-methoxybenzoic acid.
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 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, wherein the water is fed continuously or intermittently to the isomerization zone as steam.
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, wherein the weight ratio of catalyst to water per hour is from about 150:1 to about 500:1.
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, wherein the weight ratio of 2,4-dichlorophenol in the feed to water per hour is from about 5:1 to about 30:1.
Dependencies are inferred from the claim text.