Solid catalyst based on sodium hydroxide coated a hydrophobic layer for the synthesis of 4,4′-Bis (2,6-di-tert-butylphenol)

Abstract

An efficient catalyst based on solid NaOH coated a hydrophobic layer was developed in this study for the synthesis of 4,4′-bis(2,6-di-tert-butylphenol) which is one of the most commonly suggested antioxidants for polymer, fuel, and lubricant stabilization. The hydrophobic coating consists of sodium phenolate and titanate, in which sodium titanate plays a role as a skeleton framework partially covering the solid NaOH surface, enhancing its mechanical durability, while sodium phenolate fills accessible surface areas and forms catalytically active sites. The chemical properties and morphological characterizations of the catalyst were characterized using SEM-EDS, TEM, FT-IR, TLC, HPLC. It has been demonstrated that the studied catalyst was highly active and extremely stable for the first stage of 4,4′-bis(2,6-di-tert-butylphenol) synthesis. Detailed analysis of kinetic regularities for this stage showed that the reaction rate was directly proportional to the first power of catalyst amount and starting material concentration as well as to the three-half power of the oxygen concentration. Additionally, the rate law expression of this stage was established and its apparent activation energy was also determined to be approximately 38.40 kJ/mol.