Solvent free liquid-phase alkylation of phenol over solid sulfanilic acid catalyst

• DOI: 10.1016/j.apcata.2011.03.039
• Publication Date: 2011-04-14T21:35:12Z
• Authors: Farook Adam; Kasim Mohammed Hello; Tammar Hussein Ali
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract Sulfanilic acid was immobilized onto rice husk ash via 3-(chloropropyl)triethoxy-silane to form an acidic solid catalyst denoted as RHAPhSO 3 H. The BET surface area was found to be 308 m 2 g −1 . Pyridine adsorption study revealed the presence of Bronsted acid sites. The EDX analysis showed the presence of S (10.88%) and N (10.37%). The 29 Si MAS NMR showed the presence of T 2 , T 3 , Q 3 and Q 4 silicon centres. The three carbon atoms of the propyl group were evident from the 13 C MAS NMR together with a series of chemical shifts consistent with the presence of the benzene ring. In the alkylation of phenol using RHAPhSO 3 H as the catalyst resulted in 95% conversion of tert -butyl alcohol at 120 °C with 52% selectivity towards 4- tert -butylphenol. The catalyst was reused several times without significant loss of catalytic activity.