Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/48—Separation; Purification; Stabilisation; Use of additives

Definitions

• the method uses base-extraction solvents to extract base compound and impurities from the salt and recovered product.
• the residual base compound in the recovered product is removed by leaching, stripping, thermal agitating with electromagnetic waves, or evaporation with thermal decomposition.
• the residual base compound is not an impurity but a contaminant introduced by the purification process.
• the method allows eliminating crystallizers for crystallization and equipment for drying and pneumatically carrying to reduce costs.
• the purification method is combined with the oxidation and solvent recovery in prior art to use only one set of process steps, instead of two, to produce aromatic polycarboxylic acids.
• an acid-substitution solvent is added to substitute and precipitate the product acid.
• the salt may be mixed with a base-extraction solvent. It is preferred to completely dissolve ether basic salts and common salts before adding an acid- substitution solvent, and the preferred solvent is water, methanol, ethanol, alkylene glycol, or a mixture of these. Carbonyl basic salts are insoluble in most solvents, and water is a preferred acid-substitution solvent. Water is preferably added in the presence of the base- extraction solvent, such as methanol, ethanol, acetone, tetrahydrofuran, or tetrahydropyran. Acid substitution may be conducted under electromagnetic waves. Acid substitution with a base-extraction solvent reduces the inclusion of base compound and impurities in the recovered product.
• water or a base-extraction solvent can be an acid- substitution solvent for carbonyl basic salts.
• An acid-substitution solvent can be a mixture of these acids in any proportion, or a mixture of these acids with a dissolving solvent or a base-extraction solvent in a proportion that the acid is greater than 1 % by weight.
• the preferred acid-substitution solvent is aliphatic carboxylic acid, and the most preferable is acetic acid.
• water is preferred.
• the amount of acid-substitution solvent added is 0.5-100 mole per mole of carboxylic functional group in the aromatic polycarboxylic acid. It is usually added in an amount of slightly more than the mole parts of the carboxylic functional group.
• the invention tries to reduce the residual base compound by removing excessive base compound from the salt and extracting the residual compound from the recovered product.
• these efforts can reduce but cannot totally remove the residual base compound from the recovered product.
• Some of the previous steps for removing base compound may be eliminated by having higher residual base compound in the recovered product. Since removing the residual base compound is a difficult process. Therefore, it is preferred to minimize the residual base compound in the recovered product.
• This step produces aromatic polycarboxylic acids through the oxidation of the corresponding alkyl group with molecular oxygen.
• the oxidation of aromatic polycarboxylic acid has been extensively studied in the last 50 years, the invention may use any previously known prior art and is not limited to any specific one.
• a sample of 150 grams of CTA as described in Table 1 was dissolved at room temperature into a solution with composition close to flashed reactor effluent compositions.
• the solution contained 202 grams of mo ⁇ holine, 191 grams of water, 29 grams of 48% hydrobromic acid, 0.23 grams of cobalt acetate tetrahydrate, 0.3 grams of magnesium acetic tetrahydrate, and 60 grams of acetic acid.
• the temperature of this solution was raised to 110 C to dissolve the CTA and evaporate 79 c.c. of condensate.
• the solution was then cooled to room temperature for precipitation, and the filter cake was subsequently washed and leached by methanol to obtain 278 grams of wet cake.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Priority Applications (3)

Applications Claiming Priority (8)

Publications (2)

Family

ID=27493707

Family Applications (1)

Country Status (5)

Cited By (20)

Families Citing this family (1)

Citations (3)

Family Cites Families (2)

• 1999
  • 1999-11-19 JP JP2000583843A patent/JP2003510247A/ja active Pending
  • 1999-11-19 KR KR1020017006507A patent/KR100642625B1/ko not_active IP Right Cessation
  • 1999-11-19 WO PCT/US1999/027604 patent/WO2000031014A1/en not_active Application Discontinuation
  • 1999-11-19 CN CNB99813645XA patent/CN1264798C/zh not_active Expired - Fee Related
  • 1999-11-19 EP EP99967120A patent/EP1131276A4/en not_active Withdrawn

Patent Citations (3)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events