Abstract: Diaryl carbonates such as diphenyl carbonate is obtained in high yields and purity by melt crystallization from solutions of the crude product. Multi-stage crystallizations and controlled heating of the crystals purify the product.

Abstract: The invention is a catalytic ion exchange resin bed with low pressure drop, low catalyst breakage and low catalyst deactivation as well as an improved process for the production of bisphenol A employing such a catalytic ion exchange resin bed.

Abstract: The invention is a catalytic ion exchange resin bed with low pressure drop, low catalyst breakage and low catalyst deactivation as well as an improved process for the production of bisphenol A employing such a catalytic ion exchange resin bed.

Abstract: An improved process for producing Bisphenol-A which is essentially free of sodium impurity using rotary vacuum filter pumps which utilize a liquid ring seal to effect drawing a vacuum on a Bisphenol-A/phenol slurry, the improvement is in using phenol as the liquid ring seal medium.

Abstract: An improved method for the preparation of tris(4-hydroxyphenyl) compounds is provided. In particular, an improved method for preparing 1, 1, 1-tris(4'-hydroxyphenyl)ethane is provided which comprises heating a mixture comprising phenol and 4-hydroxy acetophenone in the presence of effective amounts of an ion exchange catalyst and a mercaptan as a copromoter such that the resulting 1, 1, 1-tris(4'-hydroxyphenyl)ethane is substantially free of various reaction impurities.

Abstract: A method comprising purifying impure bisphenol-A by fractional melt crystallization in a falling film dynamic crystallizer.

Abstract: Bisphenol-A produced by the condensation of acetone and phenol is freed of contaminant co-products by melting and crystallization in and from water. The final washing, in hot water, cleanses the crystal surfaces of remaining contaminants without the need for organic solvents.

Abstract: A process for improving the color of bisphenol-A and improving yields of bisphenol-A comprises the addition of hypophosphorus acid either prior to or concurrent with a distillation step.

Abstract: A method comprising purifying impure bisphenol-A by fractional melt crystallization in a falling film dynamic crystallizer.

Abstract: Product quality productivity of continuous bisphenol-A (BPA) are increased by increasing the flow rate of reactants through the reactor and decreasing % acetone conversion in the presence of an ion exchange resin catalyst and an optional free mercaptan promoter.

Abstract: Para-cumylphenol is continuously produced by the reaction of purified phenol and alpha-methylatyrene in the presence of an acidic catalyst and an effective amount of hypophosphorous acid (H.sub.3 PO.sub.2) for stabilizing the color and UV absorption.

Abstract: A method comprising purifying impure bisphenol-A by fractional melt crystallization in a falling film dynamic crystallizer.

Abstract: In the interfacial polymerization process for preparing aromatic carbonate polymers by reacting bisphenol-A with a carbonate precursor, the bisphenol-A is introduced to the reaction medium in a liquid form saturated with water.

Abstract: A method for preparing paracumylphenol in a highly selective manner which comprisesa. reacting alpha methylstyrene with a purity greater than about 99.5 wt. % with a molecular excess of phenol having a purity greater than about 99.95 wt. % in the contact presence of a solid organic cation exchange resin at a temperature of from about 40.degree. C. to about 100.degree. C. and obtaining a stream containing paracumylphenol, phenol and small quantitities of side reaction products comprising orthocumylphenol and alpha methylstyrene dimers,b. removing excess phenol and other unwanted materials which are lower boiling than paracumylphenol, thereby leaving a stream which is at least about 99 wt. % paracumylphenol.

Abstract: A process which comprises the addition of a dihydric phenol degradation inhibiting and color inhibiting effective amount of a phosphite to a composition comprising a dihydric phenol, phenol, and isomers of the dihydric phenol, said addition occurring prior to a distillation procedure.

Abstract: A process which comprises(a) contacting an excess of a phenol with a ketone in the presence of an acidic ion exchange resin catalyst;(b) recovering thereafter a stream from an acidic ion exchange resin catalyst, said stream including the dihydric phenol, unreacted phenol, isomers of the desired dihydric phenol and acid impurities derived from the acidic ion exchange resin catalyst;(c) removing a major portion of the desired dihydric phenol from the stream of (b);(d) adding to the dihydric phenol effective quantities of a Group II-a metal or transition metal of oxidation number +2 carbonate to color stablize the dihydric phenol;(e) recovering the solid dihydric phenol and the metal carbonate.

Abstract: A process which comprises(a) contacting an excess of a phenol with a ketone in the presence of an acidic ion exchange resin catalyst;(b) recovering thereafter a stream from the acidic ion exchange resin catalyst including the dihydric phenol, unreacted phenol, isomers of the desired dihydric phenol and acid impurities derived from the acidic ion exchange resin catalyst;(c) removing a major portion of the desired dihydric phenol from the stream of (b);(d) separating the stream including phenol, a small portion of the desired dihydric phenol, isomers of the desired dihydric phenol, and acidic impurities derived from the acidic ion exchange resin catalyst into a major stream and a minor stream by volume;(e) introducing into the minor stream created at step (d) sufficient quantities of a tetraorganoammonium borohydride to effectively neutralize the acidic impurities derived from the acidic ion exchange resin catalyst; and(f) recovering from the minor stream desirable dihydric phenol.

Abstract: A process which comprises(a) contacting an excess of a phenol with a ketone in the presence of an acidic ion exchange resin catalyst;(b) recovering thereafter a stream from the acidic ion exchange resin catalyst including the dihydric phenol, unreacted phenol, isomers of the desired dihydric phenol and acid impurities derived from the acidic ion exchange resin catalyst;(c) removing a major portion of the desired dihydric phenol from the stream of (b);(d) separating the stream including phenol, a small portion of the desired dihydric phenol, isomers of the desired dihydric phenol, and acidic impurities derived from the acidic ion exchange resin catalyst into a major stream and a minor stream by volume;(e) recycling the major stream so as to contact the acidic ion exchange resin catalyst of (a) together with new phenol and ketone so as to maintain a balance between the color of the final desired dihydric phenol product and impurities found therein;(f) recovering from the small stream desireable dihydric phenol,

Abstract: A process for crystallizing bisphenol-A which comprises:a. adding water to a mixture comprising bisphenol-A, about 0.5 to 15 weight percent of diphenol isomers and impurities, said mixture essentially free of phenol,b. maintaining the combined water and said mixture of (a) at a temperature sufficient to melt the solid material of step (a),c. adiabatically cooling the water and said mixture to below about 90.degree. C., andd. separating crystalline bisphenol-A from the mother liquor.

Abstract: A process for producing a dihydric phenol preferably bisphenol-A consisting of the steps of (1) formulating reaction ingredients of phenol, acetone, recycle bisphenol A, impurities, an acid catalyst and water, (2) reacting the ingredients to form a product mix consisting of bisphenol-A, unreacted phenol, by-products, acetone and water, (3) crystallizing the product mix forming a slurry of bisphenol-A/phenol adduct crystals solid phase, (4) separating the solid phase from the liquid phase by filtration, (5) removing the phenol from the bisphenol-A/phenol adduct to obtain a crude bisphenol-A, and (6) purifying the crude bisphenol by fractional melt crystallization to obtain a bisphenol-A of at least 99.5% purity.