AROMATIZATION OF TRANS-CYCLOHEXANE-1,2-DIOL INTO PYROCATECHOL - YIELDOPTIMIZATION USING A SPECIAL EXPERIMENTAL-DESIGN

The aromatization of trans-cyclohexane-1,2-diol 1 into pyrocatechol 2 is a non-selective reaction whose yield has been optimized using a spe cial experimental design. Thus, 3 g of 1 was introduced through a tubu lar reactor heated at 343-degrees-C over 40 min, with a 27 mL/min nitr ogen flow-rate. The catalytic bed is made of 200 mg of Pt/C 5% dispers ed in 20 g of powdered rock-crystal. This reaction gives 2 in 67% yiel d. If isobutene is used instead of nitrogen, the yield increases to 78 % owing to the limitation of the hydrogenolysis of 2 into phenol. A re action scheme that explains the formation of the main by-products, lik e phenol, cyclopentanone, and 2-hydroxycyclohexanone is proposed. From a technological point of view, the dispersion of supported catalyst l ike platinum on charcoal in powdered rock-crystal affords a catalytic bed that is very easy to use, has good mechanical characteristics, and a low product retention.