Processes of producing cresols from a phenols containing feed are described. The processes involve a combination of dealkylation and transalkylation processes. The dealkylation process converts the heavy alkylphenols in an alkylphenols stream to phenol and olefins. The olefins produced in the dealkylation process are separated out. The methylphenols, which are not converted in the dealkylation process, and phenol react in the transalkylation process to generate cresols.

A process for the treatment of waste water, spent air, and hydrocarbon containing liquid and gaseous streams in the cumene/phenol complex is described. Various effluent streams are combined in appropriate collection vessels, including a spent air knockout drum, a hydrocarbon buffer vessel, a fuel gas knockout drum, a phenolic water vessel, and a non-phenolic water vessel. Streams from these vessels are sent to a thermal oxidation system.

A process for the treatment of waste water, spent air, and hydrocarbon containing liquid and gaseous streams in the cumene/phenol complex is described. Various effluent streams are combined in appropriate collection vessels, including a spent air knockout drum, a hydrocarbon buffer vessel, a fuel gas knockout drum, a phenolic water vessel, and a non-phenolic water vessel. Streams from these vessels are sent to a thermal oxidation system.

Processes of producing cresols from a phenols containing feed are described. The processes involve a combination of dealkylation and transalkylation processes. The dealkylation process converts the heavy alkylphenols in an alkylphenols stream to phenol and olefins. The olefins produced in the dealkylation process are separated out. The methylphenols, which are not converted in the dealkylation process, and phenol react in the transalkylation process to generate cresols.

A method for preparing a monomer composition for synthesizing recycled plastic, a monomer composition for synthesizing recycled plastic, a recycled plastic using the same, and a molded product using the same. The method includes the steps of: subjecting a polycarbonate-based resin to a depolymerization reaction; adjusting the pH of the depolymerization reaction product having a pH of 13 or more to be 8 to 12; adjusting the pH of the depolymerization reaction product whose pH is adjusted to 8 to 12 to be less than 4; and adding a crystallization solvent to the depolymerization reaction product whose pH is adjusted to less than 4 and recovering the formed aromatic diol compound crystals.