Process for the preparation of bisphenols with zeolites

12) The process according to any of the previous claims, wherein the aromatic compound containing a hydroxyl group and having at least one hydrogen atom bound to the aromatic ring is represented by the following general formula:

• 4
• wherein the substituents R1, R2, R3, R4 and R5, the same or different, are selected from H, linear alkyl containing from 1 to 6 carbon atoms and branched or cyclic alkyl containing from 3 to 6 carbon atoms, and wherein at least one of said substituents is hydrogen.

25) The process according to any of the previous claims, carried out at a temperature ranging from 130 to 230° C.

26) The process according to any of the previous claims, wherein the pressure ranges from 1.2 to 15 atmospheres.

27) The process according to any of the previous claims, wherein the aromatic compound containing a hydroxyl group and the carbonyl compound are reacted in a molar ratio which varies from 2.2 to 15.

29) The process according to any of the previous claims, carried out in the presence of a solvent selected from toluene, xylene and trimethylbenzene.

30) The process according to any of the previous claims, carried out batchwise, in semi-continuous or in continuous.

32) A process for the regeneration of an at least partially exhausted zeolitic catalyst, coming from a process for the preparation of bisphenol compounds by the condensation of a carbonyl compound containing at least two carbon atoms with an aromatic compound, containing a hydroxyl group and having at least one hydrogen atom bound to the aromatic ring, in the presence of a catalyst comprising a zeolite having a spaciousness index higher than or equal to 8, at a temperature ranging from 120 to 250° C. and a pressure higher than atmospheric pressure, said regeneration process comprising subjecting the exhausted zeolitic catalyst to treatment with an aromatic hydrocarbon containing at least one substituent selected from OH, O−, NH2, NHR, NR2, OR, NHCOR, in at least partially liquid phase and at a temperature equal to or preferably higher than that at which the preparation process of bisphenol compounds from which the exhausted catalyst derives, has been effected.

45) A process for preparing bisphenol compounds which comprises the following steps:

• a) condensation of a carbonyl compound containing at least two carbon atoms with an aromatic compound containing a hydroxyl group and having at least one hydrogen atom bound to the aromatic ring, in the presence of a catalyst comprising a zeolite having a spaciousness index greater than or equal to 8, at a temperature ranging from 120 to 250° C., until said catalyst shows at least partial deactivation;
• b) suspension of the feeding of the carbonyl compound and treatment of said deactivated catalyst with the sole feeding of the aromatic substrate, in at least partially liquid phase and at a temperature at least equal to the temperature of the condensation process of step a) until the at least partial regeneration of the catalyst,
• c) reactivation of the feeding of the carbonyl compound, after optionally re-establishing the temperature conditions used in the condensation in step a) if the regeneration has been carried out at a temperature higher than that of the condensation step.

46) The process according to the previous claim, wherein the regeneration is carried out at a WHSV ranging from 1 to 20 hours.