Claims
- 1. A process for the preparation of phenol in high yield and selectivity with substantially no tar formation by an oxidative decarboxylation of a corresponding arylcarboxylic acid having the formula ##STR3## wherein R.sub.1 through R.sub.5 can be hydrogen, C.sub.1 -C.sub.6 alkyl, cycloalkyl, aryl, aryalkyl, amino, halogen and nitro acid and wherein at least R.sub.1 or R.sub.5 is hydrogen in the presence of a Cu-containing catalyst in which the Cu concentration as a metal and relative to the reaction mixture amounts to 0.5-15 wt.% and in which the degree of oxidation of the copper can be 1.sup.+ and 2.sup.+ which comprises
- (a) oxidizing the catalyst at a temperature above the melting point of the arylcarboxylic acid with the temperature, retention time, oxidation agent, arylcarboxylic acid concentration and Cu(I) concentration being controlled so that virtually no tar is formed,
- (b) reacting the oxidized catalyst in the presence of water, but in the absence of oxygen, to form a phenol, and
- (c) separating the phenol formed.
- 2. A method for the preparation of a phenol according to claim 1 by oxidative decarboxylation in the liquid phase of the corresponding arylcarboxylic acid in the presence of a dissolved Cu-containing catalyst, the phenol being obtained through a hydrolysis step, which comprises the following process steps:
- (a) oxidizing the catalyst at a temperature of 120.degree.-190.degree. C.;
- (b) reacting the aryl carboxylic acid with the oxidized catalyst of step (a), carried out in the absence of oxygen and with the aid of water, at a temperature of 225.degree.-270.degree. C.;
- (c) separating of phenol thus obtained and recycling of reducing catalyst to step (a).
- 3. A method according to claim 2, wherein an oxygen-containing gas is used for the catalyst oxidation in a) and wherein the oxidation is carried out using a deficiency of oxygen relative to the amount of Cu in the catalyst.
- 4. A method according to claim 2, wherein the catalyst oxidation is carried out with an electrochemical potential.
- 5. A method according to claim 2 wherein the Cu-containing catalyst also contains a co-catalyst chosen from alkaline earth metals, groups V, VI, VII, VIII, lanthanides and actinides of the Periodic System of the Elements.
- 6. A method according to claim 2, wherein step (a) is carried out at a temperature of 150.degree.-180.degree. C. and wherein step (b) is carried out at a temperature of 230.degree.-250.degree. C.
- 7. A method according to claim 2, wherein the concentration of copper as a metal and relative to the reaction mixture in the oxidation step amounts to 1-10 wt.% and wherein step (b) is carried out using an amount of water that is virtually equimolar relative to the amount of arylarylcarboxylate.
- 8. A method according to claim 2, wherein unsubstituted benzoic acid is used as arylcarboxylic acid.
- 9. A process for the preparation of a phenol by an oxidative decarboxylation in a liquid phase of a corresponding arylcarboxylic acid ##STR4## wherein R.sub.1 through R.sub.5 can be hydrogen, C.sub.1 -C.sub.6 alkyl, cycloalkyl, aryl, aryalkyl, amino, halogen and nitro acid and wherein at least R.sub.1 or R.sub.2 is hydrogen in the presence of a Cu-containing catalyst in which the degree of oxidation of the copper can be 1.sup.+ and 2.sup.+, wherein the oxidative decarboxylation is carried out (i) in the presence of water, (ii) with an amount of oxygen being added such that an amount of copper remains present as Cu(I) so that a selectivity to phenol of more than 92% measured at 1 bar is obtained, and (iii) phenol is separated off.
- 10. A process according to claim 9, wherein the oxidative decarboxylation is carried out at 210.degree.-250.degree. C. and wherein at least 0.15 wt.% copper remains present as Cu(I).
- 11. A process according to claim 1 for the preparation of a phenol by an oxidation decarboxylation in a liquid phase of a corresponding arylcarboxylic acid in the presence of a Cu-containing catalyst, which comprises the following process steps:
- (a) oxidizing the catalyst at an elevated temperature under oxidation conditions for at most 20 minutes, with such an amount of oxygen being added that at least 0.04 wt.% copper remains present as Cu(I);
- (b) reacting oxidized catalyst of step (a) in the absence of oxygen, but in the presence of water, to form the phenol; and
- (c) separating phenol and recycling of reduced catalyst to step (a).
- 12. A process according to claim 11, wherein the oxidation of the catalyst is carried out with a gas containing 1-15% oxygen and wherein the oxidation is carried out in 3-10 minutes.
- 13. A process according to claim 11, wherein the Cu-containing catalyst additionally contains a co-catalyst chosen from alkaline earth metals, groups V, VI, VII, VIII, lanthanides and actinides of the Periodic System of the Elements.
- 14. A process according to claim 11, wherein step (a) is carried out at a temperature of 210.degree.-240.degree. C.
- 15. A process according to claim 11, wherein the copper concentration as metal and relative to the reaction mixture amounts to 1-10 wt.%.
- 16. A process according to claim 11, wherein step (b) is carried out with a virtually equimolar amount of water relative to the amount of Cu(II) and wherein step (b) is carried out at a temperature of 220.degree.-250.degree. C.
- 17. A process according to claim 11, wherein step (a) and step (b) are carried out at approximately the same temperature.
- 18. A process according to claim 11, wherein an unsubstituted benzoic acid is used as arylcarboxylic acid.
- 19. A process according to claim 1 for the preparation of a phenol by oxidative decarboxylation in a gas phase of a corresponding arylcarboxylic acid in the presence of a Cu-containing catalyst, which comprises the following process steps:
- (a) contacting a bed of Cu-containing catalyst under gas phase oxidation conditions with an oxidant-containing gas mixture under conditions that tar formation is virtually absent, and
- (b) contacting oxidized catalyst of step (a) with arylcarboxylic acid and steam under gas phase conditions with exclusion of oxygen, resulting in formation of gaseous phenol.
- 20. A process according to claim 19, wherein the oxidation of the catalyst in step (a) is carried out with an oxygen-containing gas and wherein the oxidation is carried out with a deficiency of oxygen relative to the amount of Cu in the catalyst.
- 21. A process according to claim 19, wherein the Cu-containing catalyst also contains a co-catalyst chosen from alkaline earth metals, groups V, VI, VII, VIII, lanthanides and actinides of the Periodic System of the Elements.
- 22. A process according to claim 19, wherein the catalyst contacted in step (a) contains virtually no phenol.
- 23. A process according to claim 19, wherein at the end of step (a), phenol present is stripped from the catalyst.
- 24. A process according to claim 19, wherein the temperature of the catalyst bed is about 120.degree.-250.degree. C. during step (a) and wherein step (a) takes about 0.1-5 minutes.
- 25. A process according to claim 19, wherein step (b) is carried out with about an equimolar amount of steam relative to the amount of Cu(II) and wherein step (b) is carried out at a temperature of about 210.degree.-350.degree. C.
- 26. A process according to claim 19, wherein an arylcarboxylic acid is used as unsubstituted benzoic acid.
- 27. A process according to claim 1 for the preparation of a phenol by an oxidative decarboxylation n a liquid phase reaction mixture of a corresponding arylcarboxylic acid in the presence of a Cu(I)-containing catalyst, which comprises the following process steps:
- (a) oxidizing of the catalyst with the temperature, retention time, oxidation agent, phenol concentration and Cu(I) concentration being chosen so that virtually no tar is formed, and wherein 4-10 weight % Cu is present in the reaction mixture and that such a quantity of Cu(I) salt is converted to Cu(II) salt that the quantity of Cu(II) salt is higher than its solubility product so that a slurry is formed,
- (b) adding a nucleating agent to step (a) for crystallization and controlling slurry formation,
- (c) reacting the oxidized catalyst containing nucleating agent of step (b) with water in the absence of oxygen in a cascade of at least two reaction zones to form a phenol, and wherein reduction of the catalyst is continued until a homogeneous solution is obtained, and
- (d) separating phenol and recycling reduced catalyst to step (a).
- 28. A process according to claim 27, wherein the oxidation of the catalyst is carried out with an oxygen-containing gas.
- 29. A process according to claim 27, wherein part of the slurry is recycled from step (c) to step (a).
- 30. A process according to claim 27, wherein the oxidation is carried out by an electrochemical potential.
- 31. A process according to claim 27, wherein the Cu-containing catalyst contains a co-catalyst chosen from alkaline earth metals, groups V, VI, VII, VIII, lanthanides and actinides of the Periodic System of the Elements.
- 32. A process according to claim 27, wherein step (a) is carried out at a temperature of about 120.degree.-270.degree. C.
- 33. A process according to claim 27, wherein the oxidation in step (a) is carried out with such a quantity of oxygen being supplied that at least 0.04 wt.% copper remains present as Cu(I) salt.
- 34. A process according to claim 33, wherein that step (a) is carried out at a temperature between 210.degree.-250.degree. C.
- 35. A process according to claim 33, wherein step (c) is carried out with a virtually equimolar quantity of water relative to the quantity of Cu(II).
- 36. A process according to claim 33, wherein step (c) is carried out in a cascade of four reaction zones.
- 37. A process according to claim 33, wherein step (c) is carried out at a temperature of 220.degree.-250.degree. C.
- 38. A process according to claim 33, wherein the arylcarboxylic acid used is unsubstituted benzoic acid.
- 39. A process according to claim 27 wherein the nucleating agent is copperbenzoate.
Priority Claims (4)
Number |
Date |
Country |
Kind |
8903098 |
Dec 1989 |
NLX |
|
09100579 |
Jun 1991 |
BEX |
|
09100582 |
Jun 1991 |
BEX |
|
09100583 |
Jun 1991 |
BEX |
|
Parent Case Info
This is a continuation-in-part application of Ser. No. 724,173 filed Jul. 1, 1991 now abandoned which in turn is a continuation application of Ser. No. 626,639 filed Dec. 12, 1990, now abandoned, the contents of which are incorporated by reference.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0434140 |
Jun 1991 |
EPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
626639 |
Dec 1990 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
724173 |
Jul 1991 |
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