Selective Solvent Free Alkylation of Phenol over Zirconium phosphate nanoparticles
Mono-alkylphenols and di-alkylphenols are used as raw materials in the production of a wide variety of materials like resins , wire enamels , surface-active agents , durable surface coatings  and else. Both heterogeneous and homogeneous catalysts have been used in the alkylation of phenol, which classically, was carried out by Friedel–Crafts alkylation using Lewis acid type catalysts .
Zirconia has been used as an active compound for the preparation of solid acid catalysts such as, sulfated and phosphates Zirconia . Here, we report the solvent free alklyation of phenol with tert-butanol by zirconium phosphate (ZP) nanoparticles (Scheme 1) and in comparison with organic solvents as the reaction medium, the following advantages are achieved: (1) higher conversion, (2) excellent selectivity, and (3) easy recovery of the product and catalyst. The formation of zirconium phosphate was investigated by means of XRD, FT-IR, SEM and TEM and the particles size are varying in the range of 25 to 120 nm. The alkylation reaction is studied in detail by varying the reaction parameters like the molar ratio of the reactants, temperature, time and catalyst loading and the reaction conditions were therefore optimized.
- Juhue, D.; Sage, J.-M. US Pat. 2009, 7488784.
- Sumbramanian, S.; Mitra, A.; Satyanarayana, C.V.V.; Chakrabarty, D.K. Appl. Catal. A: Gen. 1997, 159, 229-240.
- Krishnan, A.V.; Ojha, K.; Pradhan, N.C. Org. Process Res. Dev. 2002, 6, 132-137.
- Bandini, M.; Melloni, A. U. Angew. Chem., Int. Ed. 2004, 43, 550-556.
- Dos Santos, A.C.; Kover, W.B.; Faro, A.C. Appl. Catal. A: Gen. 1997, 153, 83-101.