UST880007I4 - Defensive publication - Google Patents
Defensive publication Download PDFInfo
- Publication number
- UST880007I4 UST880007I4 US880007DH UST880007I4 US T880007 I4 UST880007 I4 US T880007I4 US 880007D H US880007D H US 880007DH US T880007 I4 UST880007 I4 US T880007I4
- Authority
- US
- United States
- Prior art keywords
- defensive publication
- acid
- impurities
- hydrogenation
- nickel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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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
- C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
Definitions
- Purified aromatic acid is prepared from an aqueous solution of an alkali metal salt of the acid which contains reducible impurities, wherein the alkali metal is selected from the group consisting of sodium, potassium, rubidium and cesium, by reducing the impurities by catalytic hydrogenation, followed by acidifying the solution to precipitate the purified acid.
- the process is particularly useful for preparing purified terephthalic acid, especially where the reducible impurities are salts of aldehyde acids such as para-formylbenzoic acid.
- the reducible impurities are hydrogenated by contacting the aqueous solution with hydrogen in the presence of a hydrogenation catalyst at a pressure of from to about 100, preferably to p.s.i.g., and at a temperature of about from 25 to 100 C., preferably 40 to C.
- any of the known hydrogenation catalysts can be used, but preferred catalysts are nickel/kieselguhr, cobalt/kieselguhr, nickel/ aluminum oxide, active copper chromite, Raney nickel and chromium-promoted Raney nickel, with chromium-promoted Raney nickel being especially preferred.
- the amount of catalyst should be about from 0.5 to 3, preferably 1 to 2, percent by weight based on the amount of aromatic acid salt.
- the hydrogenation should generally be continued for about from 30 to minutes, with a slight excess of hydrogen over stoichiometric quantities being used to insure complete reduction of the impurities,
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Polyesters Or Polycarbonates (AREA)
Description
DEFENSIVE PUBLICATION UNITED STATES PATENT OFFICE Published at the request of the applicant or owner in accordance with the Notice of Dec. 16, 1969, 869 0.G. 687. The abstracts of Defensive Publication applications are identified by distinctly numbered series and are arranged chronologically. The heading of each abstract indicates the number of pages of specification. including claims and sheets of drawings contained in the application as originally filed. The files of these applications are available to the public for inspection and reproduction may be purchased for 30 cents a sheet.
Defensive Publication applications have not been examined as to the merits of alleged invention. The Patent Oflice makes no assertion as to the novelty of the disclosed subject matter.
PUBLISHED NOVEMBER 24, 1970 T880 007 PREPARATION OF PURI FIED AROMATIC ACID Olden E. Paris, Wilmington, Del., and Robert H. Sullivan,
Woodbury, NJ., assignors to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Jan. 15, 1970, Ser. No. 3,234 Int. Cl. C07c 51/42 US. Cl. 260-525 No Drawing. 7 Pages Specification Purified aromatic acid is prepared from an aqueous solution of an alkali metal salt of the acid which contains reducible impurities, wherein the alkali metal is selected from the group consisting of sodium, potassium, rubidium and cesium, by reducing the impurities by catalytic hydrogenation, followed by acidifying the solution to precipitate the purified acid. The process is particularly useful for preparing purified terephthalic acid, especially where the reducible impurities are salts of aldehyde acids such as para-formylbenzoic acid. The reducible impurities are hydrogenated by contacting the aqueous solution with hydrogen in the presence of a hydrogenation catalyst at a pressure of from to about 100, preferably to p.s.i.g., and at a temperature of about from 25 to 100 C., preferably 40 to C. Any of the known hydrogenation catalysts can be used, but preferred catalysts are nickel/kieselguhr, cobalt/kieselguhr, nickel/ aluminum oxide, active copper chromite, Raney nickel and chromium-promoted Raney nickel, with chromium-promoted Raney nickel being especially preferred. The amount of catalyst should be about from 0.5 to 3, preferably 1 to 2, percent by weight based on the amount of aromatic acid salt. The hydrogenation should generally be continued for about from 30 to minutes, with a slight excess of hydrogen over stoichiometric quantities being used to insure complete reduction of the impurities,
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US323470A | 1970-01-15 | 1970-01-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
UST880007I4 true UST880007I4 (en) | 1970-11-24 |
Family
ID=21704847
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US880007D Pending UST880007I4 (en) | 1970-01-15 | 1970-01-15 | Defensive publication |
Country Status (1)
Country | Link |
---|---|
US (1) | UST880007I4 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4296245A (en) | 1979-05-17 | 1981-10-20 | Stamicarbon, B.V. | Method for the preparation of a pure alkali metal benzoate and benzyl alcohol |
-
1970
- 1970-01-15 US US880007D patent/UST880007I4/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4296245A (en) | 1979-05-17 | 1981-10-20 | Stamicarbon, B.V. | Method for the preparation of a pure alkali metal benzoate and benzyl alcohol |
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