PROCESS FOR PREPARING CRESOL FROM DITOLYLETHER

Abstract

The present invention relates to a novel process for preparing cresol from ditolyl ether.

Claims

1. A process for producing cresol from ditolyl ether and water in the presence of a catalyst, wherein the catalyst consisting of at least 2 of the following oxides titanium oxide, zirconium oxide and tungsten oxide and/or a catalyst from the group of zeolites which contains at least 85% by weight of at least 2 of the following oxides selected from aluminum oxide, silicon oxide, titanium oxide, zirconium oxide and tungsten oxide is employed.

2. The process as claimed in claim 1, wherein the catalyst from the group of zeolites contains silicon oxide, aluminum oxide, titanium oxide and/or zirconium oxide.

3. The process as claimed in claim 1, wherein the catalyst from the group of zeolites contains silicon oxide and aluminum oxide and the molar ratio of silicon to aluminum is 3:1 to 300:1.

4. The process as claimed in claim 1, wherein the catalysts employed are zeolites of the types LTA, MFI, MOR, BEA, FAU.

5. The process as claimed in claim 1, wherein the catalyst additionally contains at least one element from the group of platinum metals and the reaction is performed in the presence of hydrogen.

6. The process as claimed in claim 1, wherein the proportion of the elements from the group of platinum metals is 0.1-10% by weight, based on the total amount of the catalyst.

7. The process according to claim 5, wherein the metal from the group of platinum metals is platinum and/or rhodium.

8. The process according to claim 1, wherein the process is performed at temperatures of 250 C. to 450 C.

9. The process according to claim 14, wherein the process is performed at a pressure of 0.5 bar to 300 bar.

10. The process as claimed in claim 1, wherein the catalyst from the group of zeolites contains silicon oxide and aluminum oxide and the molar ratio of silicon to aluminum is 5:1 to 250:1.

11. The process as claimed in claim 1, wherein the catalyst from the group of zeolites contains silicon oxide and aluminum oxide and the molar ratio of silicon to aluminum is 30:1 to 90:1.

12. The process as claimed in claim 4, wherein the catalysts employed are zeolites of the types MFI or MOR.

13. The process as claimed in claim 1, wherein the proportion of the elements from the group of platinum metals is 0.5-5% by weight, based on the total amount of the catalyst.

14. The process according to claim 1, wherein the process is performed at temperatures of 270 C. to 400 C.

15. The process according to claim 1, wherein the process is performed at temperatures of 300 C. to 370 C.

16. The process according to claim 1, wherein the process is performed at a pressure of 0.9 bar to 50 bar.

17. The process according to claim 1, wherein the process is performed at a pressure of 1 bar to 10 bar.

Description

EXAMPLES

[0072] The experiments specified below were performed in a steel tube having a perforated bottom plate as a reactor. Information on the type and manufacturer of the catalyst for each experiment is reported in table 1 and table 2. A gaseous mixture of ditolyl ether, water and nitrogen and/or hydrogen in the ratios reported in tables 3 and 4 was introduced into the reactor. After the reaction the product mixture was cooled to room temperature and acetone was added to obtain a single-phase mixture that was analyzed by gas chromatography with flame ionization. The results are listed in tables 3 and 4.

TABLE-US-00001 TABLE 1 Employed catalysts (CAT) Si:Al Trade name of respective CAT No. CAT Composition ratio before application of noble metal 1 (C) Al.sub.2O.sub.3 Al.sub.2O.sub.3 Alumina Spheres 1.8/210, Sasol Germany GmbH 2 (I) ZrO.sub.2, 18% by ZrO.sub.2/ WO.sub.3 SZ 61143, Saint-Gobain Ceramic wt. WO.sub.3 Materials GmbH 3 (I) H-MFI-30 SiO.sub.2/Al.sub.2O.sub.3 30:1 Clariant Produkte (Deutschland) GmbH 4 (I) H-MFI-55 SiO.sub.2/Al.sub.2O.sub.3 55:1 Sd-Chemie AG 5 (I) H-MFI-60 SiO.sub.2/Al.sub.2O.sub.3 60:1 Sd-Chemie AG 6 (I) H-MFI-90 SiO.sub.2/Al.sub.2O.sub.3 90:1 HCZP 90E, Clariant Produkte (Deutschland) GmbH 7 (I) H-MOR-40 SiO.sub.2/Al.sub.2O.sub.3 40:1 HCZM 40E, Clariant Produkte (Deutschland) GmbH 8 (I) H-MFI-30, SiO.sub.2/Al.sub.2O.sub.3 30:1 Clariant Produkte (Deutschland) 0.5% by wt. GmbH platinum 9 (I) H-MFI-55, SiO.sub.2/Al.sub.2O.sub.3 55:1 Sd-Chemie AG 0.5% by wt. platinum 10 (I) H-MFI-90, SiO.sub.2/Al.sub.2O.sub.3 90:1 HCZP 90E, Clariant Produkte 0.5% by wt. (Deutschland) GmbH platinum 11 (I) H-MFI-240, SiO.sub.2/Al.sub.2O.sub.3 240:1 Clariant Produkte (Deutschland) 0.5% by wt. GmbH platinum 12 (I) H-MFI-55, SiO.sub.2/Al.sub.2O.sub.3 55:1 Sd-Chemie AG 1% by wt. platinum 13 (I) H-MOR-40, SiO.sub.2/Al.sub.2O.sub.3 40:1 HCZM 40E, Clariant Produkte 1% by weight (Deutschland) GmbH platinum 14 (I) H-MFI-90, SiO.sub.2/Al.sub.2O.sub.3 90:1 HCZP 90E, Clariant Produkte 1% by wt. (Deutschland) GmbH rhodium 15 (I) H-MFI-60, SiO.sub.2/Al.sub.2O.sub.3 60:1 Sd-Chemie AG 1% by wt. platinum, 0.2% by wt. nickel 16 (C) Al.sub.2O.sub.3/SiO.sub.2 with SiO.sub.2/Al.sub.2O.sub.3 1:5 based on example 6 for diphenyl 20% by wt. ether in Gao et al. Applied Chem. nickel Int. Ed. 2016, 55, 1474-1478, without addition of bases 17 (C) Norit RX 1.5 C Norit RX 1.5 Extra, Cabot Norit Extra Nederland B.V. activated carbon, 0.1% by wt. platinum MFI = SiO.sub.2/Al.sub.2O.sub.3 zeolite; MOR = SiO.sub.2/Al.sub.2O.sub.3 zeolite with mordenite structure I = inventive, C = comparative example

[0073] The noble metal in the noble metal-containing catalysts (see examples 8 (I) to 15 (I)) wasas explained belowapplied by dry impregnation/ion exchange. Amounts and properties are apparent from table 2.

[0074] For the dry impregnation the noble metal source specified in table 2, dissolved in demineralized water, was added to a carrier. The amount of demineralized water corresponds to 98% of the absorption capacity of the respective carrier (see table 2). Once the solution was fully absorbed the impregnated carrier was dried at 120 C. for 1 h in a hot air stream andwith the exception of example 16 (C)calcined at temperatures of 300 C.-500 C. for 12-16 hours in a static oven. In the case of example 16 (C) dry impregnation and drying were repeated three times to allow the entire amount of noble metal solution to be applied.

[0075] For the ion exchange the noble metal doping solution was added to a support in a glass tube with a glass frit bottom and the solution was recirculated over the support for 24 h. During this time the carrier was always covered with liquid.

TABLE-US-00002 TABLE 2 Amounts and properties of the noble metal-containing catalysts Support before precious metal doping Water Absorption Doping with precious metal content/ capacity/ Volume of % by % by solution/ No. Mass/g wt. wt. Type mL Noble metal source 8 (I) 51.5 3.4 43.2 Dry 22.2 1 g H.sub.2PtCl.sub.6 solution, impregnation 25% by wt. Pt 9 (I) 51.7 3.8 40.5 Dry 20.9 1 g H.sub.2PtCl.sub.6 solution, impregnation 25% by wt. Pt 10 (I) 101.7 2.2 42.5 Ion 150.0 0.9 g exchange [Pt(NH.sub.3).sub.4]Cl.sub.2 H.sub.2O 11 (I) 51.4 3.3 51.5 Dry 25.6 1 g H.sub.2PtCl.sub.6 solution, impregnation 25% by wt. Pt 12 (I) 102.9 3.8 40.5 Ion 150.0 1.8 g exchange [Pt(NH.sub.3).sub.4]Cl.sub.2 H.sub.2O 13 (I) 106.4 7.0 38.2 Dry 40.7 1 g H.sub.2PtCl.sub.6 solution, impregnation 25% by wt. Pt 14 (I) 50.6 2.2 42.5 Dry 21.1 5 g Rh(NO.sub.3).sub.3 impregnation solution, 10% by wt. Rh 15 (I) 51.9 4.7 46.0 Dry 22.7 2 g H.sub.2PtCl.sub.6 solution, impregnation 25% by wt. Pt + 0.5 g Ni(NO.sub.3).sub.2 6H.sub.2O 16 (C) 240.0 0.8 44.0 Dry 320.0 291 g impregnation Ni(NO.sub.3).sub.2 6H.sub.2O 17 (C) 72.2 3.2 92.8 Dry 67.0 0.3 g H.sub.2PtCl.sub.6 impregnation solution, 25% by wt. Pt

TABLE-US-00003 TABLE 3 Measured results for hydrolytic cleavage of ditolyl ether at a temperature of 315 C., a pressure of 1 bar and a catalyst volume of 68 mL. The flows were as follows: 15.2 g/h of ditol ether and 13.8 g/h of water with a proportion of 20% by volume of nitrogen. DTE Cresol Cresol conversion/ selectivity/ yield/ No. Catalyst % % % 1 (C) Al.sub.2O.sub.3 1.3 51.9 0.7 2 (I) ZrO.sub.2, 18% by 23.1 54.0 12.5 wt. WO.sub.3 3 (I) H-MFI-30 13.4 74.2 9.9 4 (I) H-MFI-55 12.8 68.2 8.7 5 (I) H-MFI-60 14.3 70.5 10.1 6 (I) H-MFI-90 7.4 84.6 6.2 7 (I) H-MOR-40 15.5 46.4 7.2 C = comparative, I = inventive

[0076] Experiments 2-7 performed according to the inventive process with water showed a high conversion, a high selectivity and a high yield compared to the comparative example, example 1 (C).

[0077] Table 4: Measured results for hydrogenolytic cleavage of ditolyl ether at a temperature of 315C, a pressure of 1 bar and a catalyst volume of 68 mL. The flows were as follows: 15.2 g/h of ditolyl ether and 13.8 g/h of water with a proportion of 2000 by volume of hydrogen.

TABLE-US-00004 TABLE 4 Measured results for hydrogenolytic cleavage of ditolyl ether at a temperature of 315 C., a pressure of 1 bar and a catalyst volume of 68 mL. The flows were as follows: 15.2 g/h of ditolyl ether and 13.8 g/h of water with a proportion of 20% by volume of hydrogen. Cresol + DTE Cresol Toluene toluene conversion/ selectivity/ selectivity/ yield/ No. Catalyst % % % % 8 (I) H-MFI-30, 93.3 21.9 41.7 59.4 0.5% by wt. platinum 9 (I) H-MFI-55, 95.3 22.3 32.2 51.9 0.5% by wt. platinum 10 (I) H-MFI-90, 86.9 22.1 40.1 54.1 0.5% by wt. platinum 11 (I) H-MFI-240, 98.1 20.7 37.3 56.9 0.5% by wt. platinum 12 (I) H-MFI-55, 85.4 32.4 43.4 64.8 1% by wt. platinum 13 (I) H-MOR-40, 94.2 17.7 35.1 49.7 1% by wt. platinum 14 (I) H-MFI-90, 36.3 35.1 39.4 27.1 1% by wt. rhodium 15 (I) H-MFI-60, 96.5 16.7 32.2 47.3 1% by wt. platinum, 0.2% by wt. nickel 16 (C) .sup.1) Al.sub.2O.sub.3/SiO.sub.2 with 1.8 16.3 5.1 0.4 20% by wt. nickel 17 (C) Norit RX 1.5 Extra 4.4 32.1 42.0 3.2 activated carbon, 0.1% by wt. platinum C = comparative experiments, I = inventive .sup.1) analogously to Gao et al. Applied Chem. Int. Ed. 2016, 55, 1474-1478.

[0078] It was found that the experiments 8 (I)-13 (I) and 15 (I) performed according to the inventive process for platinum-containing catalysts, and in the case of example 14 (I) for rhodium-containing catalysts, achieved a high conversion based on ditolyl ether and a high selectivity and yield based on cresol and toluene relative to the comparative examples 16 (C) and 17 (C).

[0079] Comparative example 16 (C) also shows that the prior art use of nickel without addition of a strong base results in an extremely low conversion and a markedly lower selectivity and yield than the inventive catalysts 8 (I)-15 (I) containing at least one element of the platinum group.