Benzene Oxidation to Phenol Making Phenolic Resins for Building

14 Benzene Oxidation to Phenol Making Phenolic Resins for Building 

The world production of phenol, of ca. 8.4 Mt/a, is mostly dependent on the cumene process. The yields and selectivities of the process are almost quantitative. However, the per-pass yield is relatively low ( 8.5%) and ca. 0.6 tonne of acetone is co-produced per 1 tonne of phenol. The hydrogenation-dehydration of acetone and its recycle has been considered but is not practised commercially. 

TS-1 is a good catalyst for the hydroxylation of benzene when it is used in a highly polar medium, such as sulfolane. This promotes the fast desorption of the product thus hindering its further oxidation (Annex 2). The selectivity of 94% to phenol (plus 6% hydroquinone and catechol), obtained at 9% benzene conversion, is comparable to the per-pass yield of the cumene process. 

Closer to industrial application however, is the gas phase hydroxylation with nitrous oxide as the oxidant (Equation 39). The reaction is carried out at 350°C with a selectivity to phenol of 98%, at 27% benzene conversion. The catalyst is Fe-ZSM-5 a zeolite containing A1 and Fe in the silicalite-1 framework. Active sites are thought to be binuclear clusters of iron oxide, formed in the channels by the migration of Fe, during thermal treatments of the zeolite. Selectivity is of 

An interesting aspect is the utilization in the process of the N2O co-produced in the oxidation of KA oil to adipic acid (Section 2.2). This allows a waste product of the integrated production cycle to be reused in the first stage of the cycle also saving on disposal costs. Solutia has recently announced, but has not yet implemented, the commercialization of an integrated adipic acid process based on this concept. 

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