Method for producing thermoplastic polyhydroxyether

Claim 1

METHOD FOR PRODUCING THERMOPLASTIC POLYHYDROXYETHER HAVING A SUBSTANTIALLY COMPLETE ABSENCE OF FOOD SOLVENT EXTRACTABLES INCLUDING THE STEPS OF: (A) REACTING TOGETHER A DIHYDRIC POLYNUCLEAR PHENOL AND FROM ABOUT 0.985 TO ABOUT 1.015 MOLES OF AN EPIHALOHYDRIN PER MOLE OF DIHYDRIC POLYNUCLEAR PHENOL TOGETHER WITH FROM ABOUT 0.5 TO ABOUT 1.4 MOLES PER MOLE OF DIHYDRIC POLYNUCLEAR PHENOL OF AN ALKALI METAL HYDROXIDE UNTIL A THERMOPLASTIC POLYHYDROXYETHER HAVING A REDUCED VISCOSITY MEASURED AT 25*C. AS A 0.2 GRAM SAMPLE IN 100 MILLILITERS OF TETRAHYDROFURAN OF AT LEAST ABOVE 0.5 IS OBTAINED, (B) ADDING TO THE REACTION MASS, WHILE THE THERMOPLASTIC POLYHYDROXYETHER IS ALKALINE, A CAUSTIC RESISTANT, HYDROPHOBIC PRODUCT RECOVERY SOLVENT FOR THE REACTION PRODUCT THERMOPLASTIC POLYHYDROXYETHER, SAID SOLVENT BEING SELECTED FROM THE GROUP CONSISTING OF A MIXTURE OF AN AROMATIC HYDROCARBON HAVING 6 TO 10 CARBON ATOMS AND A SATURATED ALIPHATIC ALCOHOL HAVING 4 TO 10 CARBON ATOMS IN A WEIGHT RATIO OF 4:1 TO 1:1, AND AN ALIPHATIC KETONE CONTAINING 4 TO 10 CARBON ATOMS EXCLUSIVE OF THE CARBONYL CARBON (C) DISSOLVING THE THERMOPLASTIC POLYHYDROXYETHER IN THE PRODUCT RECOVERY SOLVENT, (D) HEATING THE RESULTANT THERMOPLASTIC POLYHYDROXYETHER SOLUTION WITH FROM ABOUT 0.1 TO 0.5 MOLE OF A MONOFUNCTIONAL COMPOUND CAPABLE OF DESTROYING EPOXY GROUPS PER MOLE OF THERMOPLASTIC POLYHYDROXY ETHER AT REFLUX TEMPERATURE UNTIL NO FREE EPOXY GROUPS REMAIN IN THE THERMOPLASTIC POLYHYDROXYETHER, (E) MIXING THE RESULTING SOLUTION WITH WATER, (F) ALLOWING THE SOLUTION/WATER MIXTURE TO FORM TWO PHASES, ONE PHASE CONTAINING THE THERMOPLASTIC POLYHYDROXYETHER, THE OTHER PHASE CONTAINING VIRTUALLY ALL FOOD SOLVENT EXTRACTABLES, (G) ACIDIFYING THE THERMOPLASTIC POLYHYDROXYETHER PHASE WITH AN AQUEOUS ACID WASH TO A PH OF LESS THAN ABOUT 4.5, (H) WASHING UNTIL ALL OF THE FOOD SOLVENT EXTRACTABLES ARE REMOVED FROM THE POLYHYDROXYETHER PHASE AND (I) SEPARATING THE THERMOPLASTIC POLYHYDROXYETHER PHASE.