METHOD FOR PRODUCING A HYDROXY COMPOUND BY DECARBOXYLATION IN THE PRESENCE OF A BRONSTED BASE

Abstract

The invention relates to a method for producing a specific hydroxy compound by decarboxylating a specific carboxylic acid compound or a salt of said carboxylic acid compound in the presence of a Bronsted base. The invention also relates to a method for producing a diaryl carbonate or a bisphenol, to a method for producing a polycarbonate and to a use of a Bronsted base during the reaction of the decarboxylation of a specific carboxylic acid compound or a salt of said carboxylic acid compound.

Claims

1. A process for producing a hydroxy compound of the formula (I) ##STR00009## in which R is a linear or branched alkyl group having 1 to 6 carbon atoms, n is 1 or 2, and m is 0, 1, 2, or 3, by decarboxylation of a carboxylic acid compound of the formula (II) or of a corresponding salt of said carboxylic acid compound of the formula (II) ##STR00010## in which R, n, and m are as defined above, wherein at least one Brønsted base is present during the decarboxylation reaction.

2. The process as claimed in claim 1, wherein the at least one Brønsted base is present in a concentration of 0.0001 mol/L to 20 mol/L based on the entire decarboxylation reaction mixture.

3. The process as claimed in claim 1, wherein the at least one Brønsted base is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium phenolate, sodium acetate, sodium phosphate, and any desired mixtures thereof.

4. The process as claimed in claim 1, wherein the reaction time of the decarboxylation reaction is longer than 5 minutes and shorter than 48 hours.

5. The process as claimed in claim 1, wherein the decarboxylation reaction is carried out in an aqueous medium.

6. The process as claimed in claim 16, wherein the at least one heterogeneous catalyst used is a zeolite.

7. The process as claimed in claim 6, wherein the zeolite has a faujasite structure.

8. The process as claimed in claim 1, wherein the cation of the salt of the carboxylic acid compound of the formula (II) is selected from the group consisting of alkali metal cations, alkaline earth metal cations, ammonium, phosphonium, cations of manganese, iron, cobalt, nickel, copper, zinc, molybdenum, cadmium, and any desired mixtures thereof.

9. The process as claimed in claim 1, wherein the carboxylic acid compound of the formula (II) or corresponding salt of the carboxylic acid compound of the formula (II) was obtained by fermentation or from sugars, lignocellulose, lignocellulose-containing materials, furans, and/or lignin.

10. The process as claimed in claim 1, wherein the hydroxy compound of the formula (I) is phenol.

11. The process as claimed in claim 1, wherein the carboxylic acid compound of the formula (II) or corresponding salt of the carboxylic acid compound of the formula (II) is selected from the group consisting of 2-hydroxybenzoic acid, 4-hydroxybenzoic acid, and the corresponding salts.

12. A process for producing a diaryl carbonate or a bisphenol, wherein the process comprises the following steps: (i) executing the process as claimed in claim 1 so as to obtain a hydroxy compound of the formula (I) and (ii) reacting the hydroxy compound of the formula (I) from step (i) with at least one ketone to obtain a bisphenol or reacting the hydroxy compound of the formula (I) from step (i) with phosgene to obtain a diaryl carbonate.

13. A process for producing a polycarbonate through the polymerization of at least one bisphenol and/or of at least one diaryl carbonate, wherein the at least one bisphenol and/or the at least one diaryl carbonate was produced by the process as claimed in claim 12.

14. A method comprising increasing the yield of a hydroxy compound of the formula (I) ##STR00011## in which R is a linear or branched alkyl group having 1 to 6 carbon atoms, n is 1 or 2, and m is 0, 1, 2, or 3, in the reaction for the decarboxylation of a carboxylic acid compound of the formula (II) or of a corresponding salt of said carboxylic acid compound of the formula (II) ##STR00012## in which R, n, and m are as defined above, utilizing at least one Brønsted base.

15. The method as claimed in claim 14, wherein the at least one Brønsted base is selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium phenolate, sodium acetate, sodium phosphate, and any desired mixtures thereof.

16. A process as claimed in claim 1, wherein the decarboxylation of a carboxylic acid compound of the formula (II) or of a corresponding salt of said carboxylic acid compound of the formula (II) is with the use of at least one heterogeneous catalyst.

17. A process for producing a polycarbonate through the polymerization of at least one bisphenol and/or of at least one diaryl carbonate, wherein that a hydroxy compound of the formula (I) is produced by the process as claimed in claim 1 and is then used as a chain terminator in the polymerization of the polycarbonate by the interfacial process.

18. A method as claimed in claim 14, wherein the decarboxylation of a carboxylic acid compound of the formula (II) or of a corresponding salt of said carboxylic acid compound of the formula (II) is with the use of at least one heterogeneous catalyst.

Description

EXAMPLES

Abbreviations

[0073] bara: Absolute pressure in bar

[0074] rpm: Revolutions per minute

[0075] .sup.1H NMR: Proton resonance spectroscopy

[0076] M: Molar concentration in mol/L

[0077] aq.: Aqueous solution

[0078] Chemicals:

[0079] 4-Hydroxybenzoic acid (4-HBA): Purity ≥99%, Sigma-Aldrich Chemie GmbH

[0080] DM water (H.sub.2O): Demineralized water from the mains supply

[0081] Sodium hydroxide (NaOH): Anhydrous, purity ≥97%, Sigma-Aldrich Chemie GmbH

[0082] aq. NaOH solution prepared from demineralized water and sodium hydroxide

[0083] Phenol: Purity ≥96%, Sigma-Aldrich Chemie GmbH

[0084] Hexadeuterodimethyl sulfoxide (DMSO-d6): Purity ≥96%, Euriso-Top GmbH

[0085] Zeolite Type Y Catalysts:

[0086] Faujasite (product reference: BCR704).

[0087] CBV 600 (CAS 1318-02-1), Zeolyst International, Inc., surface area 660 m.sup.2/g, pore size 2.43 nm, Si/Al ratio 2.5. The catalyst was calcined prior to use at 300° C. in air for 3 h.

[0088] Faujasite, Sigma-Aldrich Chemie GmbH, surface area 567 m.sup.2/g, pore size 0.67 nm, Si/Al ratio 1.6. The catalyst was used as received.

[0089] General Experimental Procedure:

[0090] A 10 mL pressure reactor was charged with 0.5 g of 4-hydroxybenzoic acid, 0.5 mL of solvent (see table 1), and 0.02 g of the respective catalyst (see table 1), flushed with argon as inert gas, and the reactor was closed. The reactor was then pressurized with argon to 3 bara, the mixture was stirred at 800 rpm for 10 min, and the pressure was released to 1.5 bara. This operation was repeated one more time before the reactor was brought to the reaction temperature of 230° C. After the appropriate reaction time (see table 1) at this temperature, the pressure reactor was cooled to room temperature and the pressure released. The reaction mixture obtained was taken up in ethanol, the solid catalyst was separated off by centrifugation (5 min, 5000 rpm, Hettich Universal 320), and the solution was freed of ethanol on a rotary evaporator. The reaction product thus isolated was then investigated by .sup.1H NMR.

[0091] .sup.1H NMR for the Determination of 4-Hydroxybenzoic Acid and Phenol in the Reaction Product:

[0092] About 100 mg of the reaction product obtained was dissolved in 0.5 mL of DMSO-d6 and a .sup.1H NMR spectrum was recorded at 400 MHz on a Bruker Avance 400. The spectra obtained were evaluated on the basis of the specific shifts and integrals shown below.

##STR00008##

TABLE-US-00001 TABLE 1 Reaction Reaction product time [molar ratio from # Catalyst Solvent [h] .sup.1H NMR] 1 Faujasite H.sub.2O 2 2:1 Phenol/ 4-hydroxybenzoic acid 2 Faujasite aq. NaOH (0.01M) 2 Phenol 3 CBV 600 H.sub.2O 2 2:1 Phenol/ 4-hydroxybenzoic acid 4 CBV 600 aq. NaOH (0.01M) 2 Phenol 5 — H.sub.2O 2 1:1 Phenol/ 4-hydroxybenzoic acid 6 — aq. NaOH (0.01M) 2 Phenol 7 — aq. NaOH (0.01M) 0.5 1:1 Phenol/ 4-hydroxybenzoic acid

[0093] As can be seen from the table, the addition of a Brønsted base results in a higher yield of phenol under otherwise identical reaction conditions (see Example 1 (comparison) and Example 2 (according to the invention); Example 3 (comparison) and Example 4 (according to the invention) and Example 5 (comparison) and Example 6 (according to the invention)). This applies to different catalysts (Faujasite and CBV 600) and also when a catalyst is not used.

[0094] By comparing Examples 4 (comparison), 5 and 6 (according to the invention), it can moreover be seen that the reaction is accelerated by the addition of the Brønsted base. After a reaction time of half an hour with addition of a Brønsted base (Example 7), the yield obtained is the same as after a reaction time of 2 h without addition of a Brønsted base (Example 5).