tert-butanol and hydrogen peroxide react over Amberlyst-15 to form tert-butyl hydroperoxide

Organic peroxides are explosive compounds that are applied as disinfectants, bleaching agents, and as initiators for polymer synthesis because of their high reactivity. Traditional homogeneous processes with H₂SO₄ catalyst produce salts, either in the neturalization step after reaction or due to the foramtion of tert-butyl hydrogen sulphate, that must be disposed of, which introduces cost and represents an environmental burden. Here, we devised a flow chemistry approach to oxidize tert-butyl alcohol (TBA) to tert-butyl hydroperoxide (TBHP) over various heterogeneous catalysts. Under acidic conditions, TBHP is the main product and di-tert-butyl peroxide (DTBP) and peroxy-ketal are by-products. The most active catalyst was Amberlyst-15, while yield of Nafion, activated carbon, and heteropoly acids (HPA) on carbon and silica matrices was less than 1% at 70°C. In in the range of 30 to 50°C, a first order kinetic expression characterizes the tert-butyl alcohol conversion well ($ {R}^2=0.99 $). The reaction rate is slow and the rate constant, $ {k}_{40^{\circ}\mathrm{C}} $, was 0.003 min⁻¹. Above 50°C, by-products reacted further to acetone, methane, ethane, and other compounds.

Mots clés

heterogeneous catalysis; hydrogen peroxide; kinetics; tert-butyl alcohol; tert-butylhydroperoxide