Claims
- 1. A process for the continous recovery of phthalic anhydride from process gases obtained in the catalytic atmospheric oxidation of o-xylene or naphthalene which comprises: washing said process gases in an absorption column at a temperature of 60.degree. to 170.degree. C with a solvent consisting essentially of C26-44 paraffins or with a hydrocarbon mixture having a boiling point of at least 360.degree. C at atmospheric pressure and containing at least 55% by weight of C26-44 paraffins, whereby phthalic anhydride from said process gases is dissolved in said paraffins; cooling said paraffins ladened with phthalic anhydride to form solid phthalic anhydride, separating said solid phthalic anhydride from the major portion of the solvent by mechanical means to form a slurry of phthalic anhydride crystals, melting said crystals and distilling said phthalic anhydride from said slurry; and recycling said paraffins to said absorption column.
- 2. A process as claimed in 1, wherein washing of the process gases with said solvent is carried out in a column at a temperature of from 70.degree. to 140.degree. C.
- 3. A process as claimed in claim 1, wherein the washing of the process gases with said solvent is carried out at temperatures of from 60.degree. to 80.degree. C in a quenching tower.
- 4. A process as claimed in claim 1, wherein the washing of the process gas with said solvent is carried out in a column at temperatures of from 90.degree. to 140.degree. C and then in a quenching tower at temperatures of from 60.degree. to 90.degree. C.
- 5. A process as claimed in claim 1 wherein said solvent consists essentially of C26-38 paraffins.
- 6. A process as claimed in claim 1 wherein said solvent leaves the absorption column at a temperature of 90.degree.-135.degree. C laden with from 0.5 to 40% by weight of phthalic and hydride.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2313306 |
Mar 1973 |
DT |
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Parent Case Info
This is a continuation, of application Ser. No. 451,135 filed Mar. 14, 1974, which application has now been abandoned.
US Referenced Citations (5)
Continuations (1)
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Number |
Date |
Country |
Parent |
451135 |
Mar 1974 |
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