Process for producig carboxylic acids
AssigneeE.I. du Pont de Nemours and Company
InventorsSamuel Duncan Housley, John A. Turner
Life of this patent
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Abstract
Improved process for producing aromatic carboxylic acids by catalytic liquid phase oxidation of a corresponding precursor in a suitable solvent comprising feeding the reactants to a first oxidation reaction zone at high pressure and high solvent ratio, wherein uptake of oxygen is less than that required for full conversion of the precursor to its corresponding carboxylic acid, and then feeding the resulting reaction medium to a second oxidation reaction zone.
Claims12
A process for producing an aromatic carboxylic acid by catalytic liquid phase oxidation of a corresponding precursor in a solvent selected from an aliphatic carboxylic acid or a non-aliphatic organic acid, said solvent optionally including water, said process comprising:
- (a) feeding the solvent, an oxidation catalyst, the precursor, and a supply of oxygen to a first reaction zone to form a reaction medium in which the solvent:precursor mass ratio is in the range of from 5-30:1 and the operating pressure is at least about 2,500 kPa;
- (b) limiting the uptake of oxygen within the reaction medium in said first reaction zone to a value which is less than that required for full conversion of the precursor to its corresponding carboxylic acid wherein aromatic carboxylic acid produced in the reaction medium in the first reaction zone substantially remains in solution;
- and
- (c) feeding the reaction medium to a second reaction zone while simultaneously reducing the pressure of the reaction medium to a value in the range of from about 500 kPa to less than 2,500 kPa.
A process for producing terephthalic acid by catalytic liquid phase oxidation of paraxylene in a solvent selected from an aliphatic carboxylic acid or a non-aliphatic organic acid, said solvent optionally including water, said process comprising:
- (a) feeding the solvent, an oxidation catalyst, the paraxylene, and a supply of oxygen to a first reaction zone to form a reaction medium in which the solvent:precursor mass ratio is in the range of from 5-30:1 and the operating pressure is at least about 2,500 kPa;
- (b) limiting the uptake of oxygen within the reaction medium in said first reaction zone to a value which is less than that required for full conversion of the paraxylene to terephthalic acid such that said terephthalic acid produced in the reaction medium in the first reaction zone substantially remains in solution;
- and
- (c) feeding the reaction medium to a second reaction zone while simultaneously reducing the pressure of the reaction medium to a value in the range of from about 500 kPa to less than 2,500 kPa.
Dependencies are inferred from the claim text.