BPA process improvement
The present disclosure enables phenol recovery, purification and recycle in a simple, economic manner from waste streams from, for example, a phenol/acetone production process, e.g., a phenol/acetone plant or an upstream cumene hydroperoxide cleavage process step, and BPA production step, for use in the reaction with acetone to produce BPA. The disclosure therefore reduces the overall consumption of phenol in the production of BPA.
1. A process for recovering phenol comprising the steps of:
(A) contacting a first waste stream from a BPA production process which has been stripped of at least a portion of volatile sulfur compounds in said waste stream and a second waste stream from a phenol/acetone production process with a hydrocarbyl stream which is substantially immiscible with said waste streams, wherein said first waste stream and said second waste stream comprise phenol, and wherein at least a portion of said phenol from said first waste stream and/or from said second waste stream is transferred into said hydrocarbyl stream; then
(B) separating said hydrocarbyl stream after contacting step (A) from said waste streams; and
(C) recovering said phenol from said hydrocarbyl stream from step (B).
2. The process of claim 1 , wherein said hydrocarbyl comprises cumene, toluene, a mixture of cumene and alpha methyl styrene (AMS), ethers, methyl tert-butyl ether, ethyl tert-amyl ether, diisopropyl ether, ketones, methyl ethyl ketone, methyl isobutyl ketone, acetate esters, propyl acetate, butyl acetate, amyl acetate, hexyl acetate, or any combination thereof.
3. The process of claim 1 , wherein step (C) comprises distilling to separate phenol from said hydrocarbyl stream, and further comprising recycling hydrocarbyl from said distillation to step (A), and recycling at least a portion of the recovered phenol to the BPA production process or to the phenol/acetone production process.
4. The process of claim 1 , wherein the combined waste stream in step (A) is distilled to recover at least a portion of acetone prior to contacting with the hydrocarbyl stream in step (A).
5. The process of claim 1 , wherein the process for producing BPA comprises the steps of:
(E) reacting acetone with a stoichiometric excess of phenol in the presence of an acidic catalyst, optionally in the presence of a cocatalyst or promoter either homogeneously fed or heterogeneously bound to an acidic catalyst, to form a reaction product stream comprising crude BPA product, unreacted phenol, optionally unreacted acetone, optionally cocatalyst or promoter, water of condensation, and other reaction byproducts;
(F) distilling in single or multistage the reaction product stream from step (E) to distill off a first distillate stream comprising water, a portion of unreacted phenol, any unreacted acetone, any cocatalyst or promoter or derivatives thereof and other reaction byproducts, which first distillate stream constitutes the BPA waste stream, and a second distillate stream having a portion of unreacted phenol, and a stream of concentrated BPA and phenol; sending said concentrated BPA and phenol stream downstream to a BPA purification step comprising one or more solid-liquid separation and wash steps;
(G) producing purified BPA by crystallization of the concentrated BPA phenolic feed stream of step (F); and
(H) separating the purified BPA crystals of step (G) by solid-liquid separation and washing same in one or multiple stages with a wash stream which may include at least a portion of the second distillate stream, or spent wash or mother liquor from one or more subsequent crystallization, solid-liquid separation, and wash steps, to produce a washed BPA-phenol adduct, a spent wash stream and a mother liquor stream; and
(I) heating and removing phenol from the washed purified BPA-phenol adduct from the crystallization and solid-liquid separation to produce a purified BPA melt stream where the removed phenol is recycled in whole or in part, to steps (E) or (G).
6. The process of claim 1 , wherein the phenol/acetone production process comprises a first step of forming cumene hydroperoxide by oxidation of cumene, a second step of forming phenol and acetone by cleavage of cumene hydroperoxide in the presence of an acid catalyst, a third step of neutralizing effluent from the cleavage step, and a fourth step of separating and purifying the neutralized cleavage effluent to form purified phenol and acetone product streams.
7. The process of claim 6 , wherein a portion of said phenol recovered in step (C) is returned to the third or fourth step of the phenol/acetone production process.
8. The process of claim 5 , wherein step (E) is conducted in the presence of added promoter selected from the group consisting of methyl mercaptan, ethyl mercaptan, 2,2-bis(methylthio)propane, and mercaptocarboxylic acid.