Recycling of valuable chemicals through the catalytic decomposition of phenol tar in cumene process

The base catalyst LZ-2, which was the mixture of CaO and Na–NaOH/Al2O3·3H2O, was chosen for the decomposition of phenol tar to generate valuable chemicals. The selectivity of LZ-2 for dimethyl phenyl carbinol, α-methyl styrene dimer and cumenyl phenol was 100%, 100% and 98%, respectively. Under the optimum operating conditions of catalyst 2.5 wt%, operating temperature 603.15 K and decomposition time 3.5 h, decomposition ratios of cumenyl phenol and dimethyl phenyl carbinol were 98.7% and 99.97%, respectively. In addition, the experimental repeatability demonstrated that the total yield of valuable chemicals still reached 90.1% after the catalyst being used five times. Mass and energy balance indicated that the catalytic decomposition was a high potential for the recycling of chemicals from phenol tar.

► A base catalyst is used for decomposing phenol tar to recycle valuable chemicals.
► The decomposition ratio of cumenyl phenol is 98.7%.
► The decomposition ratio of dimethyl phenyl carbinol is 99.97%.
► This technique can recycle over 90% valuable chemicals from tar with low energy.
► The process can minimize the waste tar and bring considerable economic benefits.