Process for producing bisphenol-A

1. A process for producing 2,2-bis(4-hydroxyphenyl)propane (p,p-BPA), comprising:

providing a liquid stream comprising phenol and 2,4,4-trimethyl-2-(4-hydroxyphenyl)chroman (chroman 1.5); and

feeding the liquid stream to an acidic ion exchange resin at a temperature of from about 45° C. to about 100° C. to produce an effluent stream containing p,p-BPA, the acidic ion exchange resin having greater than 2% crosslinkage.

2. The process of claim 1 , wherein the chroman 1.5 comprises from about 0.1 weight percent to about 6 weight percent of the liquid stream.

3. The process of claim 1 , wherein the liquid stream further comprises a mercaptan selected from the group consisting of 3-mercaptopropionic acid, an ethene thiol, a propane thiol, an aliphatic thiol, and an aromatic thiol.

4. The process of claim 1 , wherein the acidic ion exchange resin has from 6% to 10% crosslinkage.

5. The process of claim 1 , wherein the acidic ion exchange resin is a resin selected from the group consisting of sulfonated styrenedivinylbenzene resins, sulfonated styrene resins, phenol formaldehyde sulfonic acid resins, and benzene formaldehyde sulfonic acid resins.

6. The process of claim 1 , wherein the ion exchange resin contains sulfonic acid groups.

7. The process of claim 1 , wherein the temperature is from about 53° C. to about 93° C.

8. The process of claim 1 , wherein the temperature is from about 80° C. to about 95° C.

9. The process of claim 1 , wherein the liquid stream in the ion exchange resin has a weight hourly space velocity WHSV, and the weight hourly space velocity WHSV of the liquid stream in the ion exchange resin is from 0 to about 20 hr −1 .

10. The process of claim 1 , wherein the liquid stream in the ion exchange resin has a weight hourly space velocity WHSV, and the weight hourly space velocity WHSV of the liquid stream in the ion exchange resin is from about 0.5 hr −1 to about 5 hr −1 .

11. The process of claim 1 , wherein the effluent stream comprises from about 1 weight percent to about 12 weight percent of p,p-PBA.

12. A process for converting 2,4,4-trimethyl-2-(4-hydroxyphenyl)chroman (chroman 1.5) into 2,2-bis(4-hydroxyphenyl)propane (p,p-BPA), comprising:

providing a liquid stream comprising phenol and chroman 1.5; and

feeding the liquid stream to an acidic ion exchange resin at a temperature of from about 45° C. to about 100° C. to convert at least 50 weight percent of the chroman 1.5 to p,p-BPA.

13. The process of claim 12 , wherein the chroman 1.5 comprises from about 0.1 weight percent to about 6 weight percent of the liquid stream.

14. The process of claim 12 , wherein the acidic ion exchange resin has greater than 2% crosslinkage.

15. The process of claim 12 , wherein the acidic ion exchange resin has 8% crosslinkage.

16. The process of claim 12 , wherein the acidic ion exchange resin has 20% crosslinkage.

17. The process of claim 12 , wherein the temperature is from about 53° C. to about 93° C.

18. The process of claim 12 , wherein the liquid stream in the ion exchange resin has a weight hourly space velocity WHSV, and the weight hourly space velocity WHSV of the liquid stream in the ion exchange resin is from 0 to about 20 hr −1 .

19. The process of claim 12 , wherein the liquid stream in the ion exchange resin has a weight hourly space velocity WHSV, and the weight hourly space velocity WHSV of the liquid stream in the ion exchange resin is from about 0.5 to about 5 hr −1 .

20. The process of claim 12 , wherein at least 70 weight percent of the chroman 1.5 is converted to p,p-BPA.

21. The process of claim 12 , wherein at least 90 weight percent of the chroman 1.5 is converted to p,p-BPA.