CC BY-ND-NC 4.0 · Synlett 2019; 30(04): 405-412
DOI: 10.1055/s-0037-1611678
Copyright with the author

Catalytic Hydrogenolysis of Substituted Diaryl Ethers by Using Ruthenium Nanoparticles on an Acidic Supported Ionic Liquid Phase ([email protected]3H)

Simon Rengshausen
a  Max-Planck-Institut für Chemische Energiekonversion, Stift­straße 34-36, 45470 Mülheim an der Ruhr, Germany
b  Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany   Email: [email protected]
Fabian Etscheidt
b  Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany   Email: [email protected]
Johannes Großkurth
b  Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany   Email: [email protected]
Kylie L. Luska
b  Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany   Email: [email protected]
a  Max-Planck-Institut für Chemische Energiekonversion, Stift­straße 34-36, 45470 Mülheim an der Ruhr, Germany
a  Max-Planck-Institut für Chemische Energiekonversion, Stift­straße 34-36, 45470 Mülheim an der Ruhr, Germany
b  Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany   Email: [email protected]
› Author Affiliations
This work was supported by the Cluster of Excellence ‘Tailor-Made Fuels from Biomass’, which is funded under contract EXC 236 by the Excellence Initiative by the German federal and state governments to promote science and research at German universities.
Further Information

Publication History

Received: 18 November 2018

Accepted after revision: 04 February 2019

Publication Date:
15 February 2019 (online)

Published as part of the 30 Years SYNLETT – Pearl Anniversary Issue


Catalytic hydrogenolysis of diaryl ethers is achieved by using ruthenium nanoparticles immobilized on an acidic supported ionic liquid phase ([email protected]3H) as a multifunctional catalyst. The catalyst components are assembled through a molecular approach ensuring synergistic action of the metal and acid functions. The resulting catalyst is highly active for the hydrogenolysis of various diaryl ethers. For symmetric substrates such as diphenyl ether, hydrogenolysis is followed by full hydrodeoxygenation producing the corresponding cycloalkanes as the main products. For unsymmetric substrates, the cleavage of the C–O bond is regioselective and occurs adjacent to the unsubstituted phenyl ring. As hydrogenation of benzene is faster than hydrodeoxygenation over the [email protected]3H catalyst, controlled mixtures of cyclohexane and substituted phenols are accessible with good selectivity. Application of [email protected]3H catalyst in continuous-flow hydrogenolysis of 2-methoxy-4-methylphenoxybenzene is demonstrated with use of commercial equipment.

Supporting Information

  • References and Notes

    • 1a Cornella J, Zarate C, Martin R. Chem. Soc. Rev. 2014; 43: 8081
    • 1b Bhatt MV, Kulkarni SU. Synthesis 1983; 249
    • 1c Sergeev AG, Hartwig JF. Science 2011; 332: 439
    • 1d Samant BS, Kabalka GW. Chem. Commun. 2012; 48: 8658
    • 2a Barta K, Ford PC. Acc. Chem. Res. 2014; 47: 1503
    • 2b Zhang ZR, Song JL, Han BX. Chem. Rev. 2017; 117: 6834
    • 2c Li CZ, Zhao XC, Wang AQ, Huber GW, Zhang T. Chem. Rev. 2015; 115: 11559
    • 2d Zakzeski J, Bruijnincx PC, Jongerius AL, Weckhuysen BM. Chem. Rev. 2010; 110: 3552
    • 2e Xu CP, Arancon RA. D, Labidi J, Luque R. Chem. Soc. Rev. 2014; 43: 7485
    • 2f Zaheer M, Kempe R. ACS Catal. 2015; 5: 1675
    • 3a Dorrestijn E, Laarhoven LJ. J, Arends IW. C. E, Mulder P. J. Anal. Appl. Pyrol. 2000; 54: 153
    • 3b Parthasarathi R, Romero RA, Redondo A, Gnanakaran S. J. Phys. Chem. Lett. 2011; 2: 2660
    • 4a Nichols JM, Bishop LM, Bergman RG, Ellman JA. J. Am. Chem. Soc. 2010; 132: 12554
    • 4b Kusumoto S, Nozaki K. Nat. Commun. 2015; 6: 6296
    • 4c vom Stein T, Weigand T, Merkens C, Klankermayer J, Leitner W. ChemCatChem 2013; 5: 439
    • 4d Deuss PJ, Scott M, Tran F, Westwood NJ, de Vries JG, Barta K. J. Am. Chem. Soc. 2015; 137: 7456
    • 4e Weickmann D, Plietker B. ChemCatChem 2013; 5: 2170
    • 4f Saper NI, Hartwig JF. J. Am. Chem. Soc. 2017; 139: 17667
    • 5a Van den Bosch S, Schutyser W, Vanholme R, Driessen T, Koelewijn SF, Renders T, De Meester B, Huijgen WJ. J, Dehaen W, Courtin CM, Lagrain B, Boerjan W, Sels BF. Energ. Environ. Sci. 2015; 8: 1748
    • 5b Cui XJ, Yuan HK, Junge K, Topf C, Beller M, Shi F. Green Chem. 2017; 19: 305
    • 5c Cao Z, Engelhardt J, Dierks M, Clough MT, Wang G.-H, Heracleous E, Lappas A, Rinaldi R, Schüth F. Angew. Chem. Int. Ed. 2017; 56: 2334
    • 5d Song Q, Wang F, Xu J. Chem. Commun. 2012; 48: 7019
    • 5e Wu HR, Song JL, Xie C, Wu CY, Chen CJ, Han BX. ACS Sustain. Chem. Eng. 2018; 6: 2872
    • 5f He JY, Zhao C, Lercher JA. J. Am. Chem. Soc. 2012; 134: 20768
    • 5g Wang XY, Rinaldi R. Catal. Today 2016; 269: 48
    • 5h Wang M, Shi H, Camaioni DM, Lercher JA. Angew. Chem. Int. Ed. 2017; 56: 2110
    • 5i Chatterjee M, Ishizaka T, Suzuki A, Kawanami H. Chem. Commun. 2013; 49: 4567
    • 6a van Duzee EM, Adkins H. J. Am. Chem. Soc. 1935; 57: 147
    • 6b Gao F, Webb JD, Hartwig JF. Angew. Chem. Int. Ed. 2016; 55: 1474
    • 6c Sergeev AG, Webb JD, Hartwig JF. J. Am. Chem. Soc. 2012; 134: 20226
    • 6d He JY, Zhao C, Mei DH, Lercher JA. J. Catal. 2014; 309: 280
    • 6e Zaheer M, Hermannsdorfer J, Kretschmer WP, Motz G, Kempe R. ChemCatChem 2014; 6: 91
    • 6f Zhang JG, Teo J, Chen X, Asakura H, Tanaka T, Teramura K, Yan N. ACS Catal. 2014; 4: 1574
    • 6g Zhang JG, Asakura H, van Rijn J, Yang J, Duchesne P, Zhang B, Chen X, Zhang P, Saeys M, Yan N. Green Chem. 2014; 16: 2432
    • 6h Wang X, Rinaldi R. ChemSusChem 2012; 5: 1455
  • 7 Ren YL, Tian M, Tian XZ, Wang Q, Shang HT, Wang JJ, Zhang ZC. Catal. Commun. 2014; 52: 36
  • 8 Ren Y, Yan M, Wang J, Zhang ZC, Yao K. Angew. Chem. Int. Ed. 2013; 52: 12674
    • 9a Bulut S, Siankevich S, van Muyden AP, Alexander DT. L, Savoglidis G, Zhang JG, Hatzimanikatis V, Yan N, Dyson PJ. Chem. Sci. 2018; 9: 5530
    • 9b Wang H, Ruan H, Feng M, Qin Y, Job HM, Luo L, Wang C, Engelhard MH, Kuhn E, Chen X, Tucker MP, Yang B. ChemSusChem 2017; 1846
    • 9c Huang YB, Yan L, Chen MY, Guo QX, Fu Y. Green Chem. 2015; 17: 3010
    • 9d Zhang W, Chen JZ, Liu RL, Wang SP, Chen LM, Li KG. ACS Sustain. Chem. Eng. 2014; 2: 683
    • 10a Park HW, Hong UG, Lee YJ, Song IK. Catal. Commun. 2012; 20: 89
    • 10b Jin SH, Xiao ZH, Chen X, Wang L, Guo J, Zhang M, Liang CH. Ind. Eng. Chem. Res. 2015; 54: 2302
    • 11a Zhao C, Lercher JA. ChemCatChem 2012; 4: 64
    • 11b Yan N, Yuan YA, Dykeman R, Kou YA, Dyson PJ. Angew. Chem. Int. Ed. 2010; 49: 5549
    • 11c Wang HL, Ruan H, Pei HS, Wang HM, Chen XW, Tucker MP, Cort JR, Yang B. Green Chem. 2015; 17: 5131
    • 11d Luo ZC, Zheng ZX, Wang YC, Sun G, Jiang H, Zhao C. Green Chem. 2016; 18: 5845
    • 12a Luska KL, Julis J, Stavitski E, Zakharov DN, Adams A, Leitner W. Chem. Sci. 2014; 5: 4895
    • 12b Luska KL, Migowski P, El Sayed S, Leitner W. Angew. Chem. Int. Ed. 2015; 54: 15750
    • 12c Luska KL, Migowski P, El Sayed S, Leitner W. ACS Sustain. Chem. Eng. 2016; 4: 6186
    • 12d Luska KL, Migowski P, Leitner W. In Nanocatalysis in Ionic Liquids 2016
    • 12e Offner-Marko L, Bordet A, Moos G, Tricard S, Rengshausen S, Chaudret B, Luska KL, Leitner W. Angew. Chem. Int. Ed. 2018; 57: 12721
  • 13 Experimental Procedures Safety warning: High-pressure experiments with compressed H2 must be carried out only with appropriate equipment and under rigorous safety precautions.General: If not otherwise stated, the syntheses of the ionic liquids (ILs), the supported ionic liquid phases (SILPs), and the nanoparticles immobilized on SILPs ([email protected] and [email protected]3H) were carried out under an inert atmosphere by using standard Schlenk techniques or inside a glovebox. After synthesis, ILs, SILPs, [email protected], and [email protected]3H were stored under an inert atmosphere. If not otherwise stated solvents were used after distillation without any further purification. For reactions under an inert atmosphere, solvents were additionally dried with molecular sieves (4 Å) and degassed by flushing solvents with argon. For catalysis decalin (from ACROS, 99% anhydrous) was used without purification. The precursor [Ru(2-methylallyl)2(cod)] was commercially available from Umicore. All other chemicals and solvents were purchased from commercial suppliers and used without purification.Synthesis of catalysts: The [email protected], [email protected]3H, and [email protected]3H were synthesized as previously reported and [email protected]2 was synthesized accordingly.12a Synthesis of substrates: The synthesis of diarylethers was carried out as previously reported.1cA round-bottom Schlenk-flask (250 mL) was equipped with a magnetic stir bar, copper iodide (456 mg, 2.40 mmol, 10.0 mol%), picolinic acid (590 mg, 4.80 mmol, 20.0 mol%), and potassium phosphate (10.2 g, 48.0 mmol, 2.00 equiv). A second Schlenk flask (100 mL) was charged with the aryl iodide (24.0 mmol, 1 equiv), the phenol (28.8 mmol, 1.2 equiv), and anhydrous DMSO (50 mL). The solution of flask 2 was transferred into flask 1 under flowing Argon and the reaction mixture was stirred for 20 h at 100 °C, subsequently. After cooling down, the reaction mixture was diluted with a 1:1 mixture of a saturated aqueous solution of NH4Cl (200 mL) and H2O (200 mL). After extraction with CH2Cl2 (3 × 200 mL) the combined organic phases were washed with a 5% aqueous solution of KOH (300 mL) and brine (300 mL). After drying the mixture with Na2SO4 the solvent was removed and the crude reaction mixture was preadsorbed on silica gel. The purification of the crude mixture was achieved with use of silica gel. Remaining iodine compounds caused the deactivation of the catalyst in subsequent catalytic reactions and therefore had to be separated carefully. This afforded in some cases purification by two subsequent chromatography columns. Full characterization of all substrates can be found in the Supporting Information.2,6-Dimethoxy-4-methylphenoxybenzene: Prepared according to the general procedure by using iodobenzene (5.00 g, 24.0 mmol) and 2,6-dimethoxy-4-methylphenol (4.8 g, 28.8 mmol). The crude product was purified by flash column chromatography (eluent: ethyl acetate/n-pentane 1:8). 2,6-Dimethoxy-4-methylphenoxybenzene was obtained as a slightly off-white solid (4.46 g, 18.3 mmol) in 76% yield. 1H NMR (500 MHz, CDCl3): δ = 7.29–7.26 (m, 2 H), 7.02–6.98 (m, 1 H), 6.93–6.90 (m, 2 H), 6.51 (s, 2 H), 3.79 (s, 6 H), 2.42 (s, 3 H) ppm. 13C NMR (125.7 MHz, CDCl3): δ = 158.77 (C), 153.23 (C), 135.65 (C), 129.84 (C), 129.39 (CH), 121.52 (CH), 114.87 (CH), 106.28 (CH), 56.33 (CH3), 22.24 (CH3) ppm. HRMS (EI): m/z 244.11.Batch catalysis: In a typical experiment, [email protected] (37.5 mg, 0.0012 mmol Ru), substrate (0.6 mmol, 500 equiv), and decalin (0.5 mL) were combined in a glass insert and placed in a high-pressure autoclave. After purging the autoclave with H2, the reaction mixture was stirred at 170 °C in an aluminium heating cone under 120 bar H2 (pressurized at 100 bar H2 at rt). After the reaction, the autoclave was cooled in an ice bath, carefully vented, and the reaction mixture filtered before GC analysis with use of hexadecane as an internal standard. In some cases a gap in mass balance was observed because of the loss of cyclohexane in the headspace of the autoclave (scale-up decreased this error).Isolated yield (5a): The catalysis was scaled up by a factor of 5. After reaction the decalin phase was isolated and the catalyst washed with decalin (1 × 5 mL). The combined organic phases were extracted with aqueous KOH (3 × 10 mL, 0.3 M). The KOH phase was washed with n-pentane (3 × 10 mL) and neutralized with aqueous HCl, subsequently. After neutralization, the aqueous phase was extracted with CH2Cl2 (4 × 20 mL). After drying the CH2Cl2 phase with MgSO4 and removal of the solvent a yellow-brownish oil (186 mg, 1.35 mmol) was obtained in 45% yield (See Supporting Information, Figure S11 for characterization).Continuous flow catalysis: A 70 mm CatCart® (Vpacked reactor = 0.5126 mL) was filled with [email protected]3H (439 mg, 0,014 mmol Ru) and installed into the H-Cube ProTM. Prior to catalysis the catalyst was flushed with decalin (1 mL min–1 for 30 min). Then, the reactor was pressurized to 40 bar H2 (90 NmL min–1) and heated to 170 °C. When reaching stable reaction conditions, the substrate solution (0.025 M in decalin) was introduced into the system (0.3 mL min–1). The reaction was allowed to equilibrate for 30 min before the first samples were collected. The reaction mixture was analysed by GC analysis with use of hexadecane as an internal standard.
  • 14 Mellmer MA, Sener C, Gallo JM. R, Luterbacher JS, Alonso DM, Dumesic JA. Angew. Chem. Int. Ed. 2014; 53: 11872