The present disclosure relates to a method of decomposing a phenolic by-product, including: a step of feeding and thermally cracking a phenolic by-product stream to and in a decomposition apparatus, recovering an active ingredient from a top discharge stream, and discharging a high-boiling substance through a bottom discharge stream; a step of pressurizing each of a side discharge stream of the decomposition apparatus and a bottom discharge stream of the decomposition apparatus; a step of mixing the pressurized side discharge stream of the decomposition apparatus and the pressurized bottom discharge stream of the decomposition apparatus with each other to form a mixed stream; and a step of passing a part of the mixed stream through a reboiler, circulating the part of the mixed stream to the decomposition apparatus, and discharging a residual mixed stream.

The present disclosure relates to a method of decomposing a phenolic by-product, including: a step of feeding and thermally cracking a phenolic by-product stream to and in a decomposition apparatus, recovering an active ingredient from a top discharge stream, and discharging a high-boiling substance through a bottom discharge stream; a step of pressurizing each of a side discharge stream of the decomposition apparatus and a bottom discharge stream of the decomposition apparatus; a step of mixing the pressurized side discharge stream of the decomposition apparatus and the pressurized bottom discharge stream of the decomposition apparatus with each other to form a mixed stream; and a step of passing a part of the mixed stream through a reboiler, circulating the part of the mixed stream to the decomposition apparatus, and discharging a residual mixed stream.

The present disclosure relates to a method of decomposing a phenolic by-product, including: a step of feeding and thermally cracking a phenolic by-product stream to and in a decomposition apparatus, recovering an active ingredient from a top discharge stream, and discharging a high-boiling substance through a bottom discharge stream; a step of pressurizing each of a side discharge stream of the decomposition apparatus and a bottom discharge stream of the decomposition apparatus; a step of mixing the pressurized side discharge stream of the decomposition apparatus and the pressurized bottom discharge stream of the decomposition apparatus with each other to form a mixed stream; and a step of passing a part of the mixed stream through a reboiler, circulating the part of the mixed stream to the decomposition apparatus, and discharging a residual mixed stream.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

A method for producing bisphenol A (BPA) is provided. The method includes step A of degrading a polycarbonate resin in a solvent and distilling off the solvent to obtain a crude solution A; step B of subjecting acetone and phenol to dehydration condensation; step C of distilling off unreacted acetone and water to obtain a concentrated liquid C; step D of crystallizing the concentrated liquid C to obtain a slurry liquid, from which a mother liquor D is obtained; step H of obtaining a solution H1 or a solution H2 from the crude solution A and part of the mother liquor D; and step I of supplying the solution H1 or H2 to the step B or C. The solution H1 contains BPA obtained by degrading BPA contained in the crude solution A and the mother liquor D into phenol and isopropenylphenol and then rebonding phenol and isopropenylphenol, and the solution H2 contains phenol obtained by degrading BPA contained in the crude solution A and the mother liquor D into phenol and acetone.

A method for producing bisphenol A (BPA) is provided. The method includes step A of degrading a polycarbonate resin in a solvent and distilling off the solvent to obtain a crude solution A; step B of subjecting acetone and phenol to dehydration condensation; step C of distilling off unreacted acetone and water to obtain a concentrated liquid C; step D of crystallizing the concentrated liquid C to obtain a slurry liquid, from which a mother liquor D is obtained; step H of obtaining a solution H1 or a solution H2 from the crude solution A and part of the mother liquor D; and step I of supplying the solution H1 or H2 to the step B or C. The solution H1 contains BPA obtained by degrading BPA contained in the crude solution A and the mother liquor D into phenol and isopropenylphenol and then rebonding phenol and isopropenylphenol, and the solution H2 contains phenol obtained by degrading BPA contained in the crude solution A and the mother liquor D into phenol and acetone.

The present disclosure relates to a monomer composition for synthesizing recycled plastic that contains a high-purity aromatic diol compound recovered through recycling by chemical decomposition of a polycarbonate-based resin, a method for preparing the same, and a recycled plastic and molded product using the same.

The present disclosure relates to a monomer composition for synthesizing recycled plastic that contains a high-purity aromatic diol compound recovered through recycling by chemical decomposition of a polycarbonate-based resin, a method for preparing the same, and a recycled plastic and molded product using the same.

Provided is a method of decomposing phenol-based by-product, and more particularly, a method of decomposing phenol-based by-product including: introducing a phenol-based by-product stream, a first stream of a side discharge stream from a decomposition device, and a process water stream to a mixing device and mixing the streams; introducing a discharge stream from the mixing device to a layer separation device to phase-separate the discharge stream into an oil phase and an aqueous phase; passing an oil stream discharged from the layer separation device through any one or more of a first heat exchanger and a second heat exchanger and introducing the oil stream to the decomposition device to carry out decomposition; and supplying the first stream of the side discharge stream from the decomposition device to the mixing device, forming a mixed stream of a second stream of the side discharge stream with a lower discharge stream and discharging the mixed stream, and recovering effective components from an upper discharge stream.