Acetone → BPA phenol

Participants

Reaction Steps

In general, BPA is produced in accordance with the present invention by (a) reacting acetone with a stoichiometric excess of phenol under acidic conditions, possibly in the presence of a cocatalyst or promoter, e.g. a thiol compound, to form a reaction product stream comprising crude bisphenol-A product, unreacted phenol, possibly unreacted acetone, possibly cocatalyst or promoter if present in the reaction, water of condensation, and other reaction byproducts; (b) distilling in single or multistage the reaction product stream from step (a) to distill off a volatilized unreacted phenol stream, possibly an unreacted acetone stream, possibly a stream containing cocatalyst or promoter if present in step (a) and the water of condensation, while sending the resulting concentrated BPA phenolic feed stream, consisting essentially of phenol in which the bisphenol-A and byproducts have been concentrated, downstream to a BPA-phenol adduct crystallization and purification step, said purification step comprising one or more solid-liquid separation and wash steps; (c) producing BPA-phenol adduct crystals by crystallization of the concentrated BPA phenolic feed stream in each crystallization, solid-liquid separation and wash where cooling for said crystallization utilizes vaporization of an alkane hydrocarbon or mixture of hydrocarbons containing from 4 to 6 carbons, e.g. pentane; (d) separating the BPA-phenol adduct crystals by solid-liquid separation, such as, for example, by centrifugation or filtration, and washing in one or multiple stages the BPA-phenol adduct crystals with a wash phenol stream which may include at least a portion of the volatilized unreacted phenol stream recovered from step (b), or spent wash or mother liquor from subsequent crystallization, solid-liquid separation, and wash steps, to produce final washed BPA-phenol adduct, final spent wash and final mother liquor; (e) cracking a stream comprising at least a portion, for example from about 0.5 to about 20 wt. %, preferably from about 1 to about 10 wt. %, more preferably from about 2 to about 7 wt. %, of said final mother liquor of step (d) in a reactor with basic or acidic cracking catalyst, for example sodium hydroxide or aluminum chloride, under reaction conditions selected to recover a product comprising from about 60 to about 90 wt. % of said stream as phenol having a purity level of from about 95 to about 100 wt. %, and from about 10 to about 40 wt. % of said stream as heavy residue byproduct; and (f) recovering and feeding the phenol product of step (e) to step (a) as phenol reactant and/or step (d) as wash phenol.

Provenance & Evidence