Plural stage hydrogenation of dialkyl terephthalate using palladium and then copper chromite

Claim 2

A PROCESS FOR THE PREPARATION OF 1,4-CYCLOHEXANEDIMETHANOL WHICH COMPRISES REACTING A DIALKYL TEREPHTHALATE WITH HYDROGEN IN A FIRST HYDROGENATION STAGE IN THE PRESENCE OF A PALLADIUM HYDROGENATION CATALYST UNDER HYDROGENATION CONDITIONS, PASSING EFFLUENT FROM SAID FIRST HYDROGENATION STAGE THROUGH A SECOND HYDROGENATION STAGE IN THE PRESENCE OF A COPPER CHROMITE HYDROGENATION CATALYST UNDER HYDROGENATION CONDITIONS, AND RECOVERING 1,4-CYCLOHEXNEDIMETHANOL FROM SAID SECOND HYDROGENATION STAGE.

Claim 3

A PROCESS FOR THE CONTINUOUS HYDROGENATION OF DIMETHYL TEREPHTHALATE TO 1,4-CYCLOHEXANEDIMETHANOL WHICH COMPRISES INTRODUCING DIMETHYL TEREPHTHALATE TO A FIRST HYDROGENATION STAGE CONTAINING A PALLADIUM HYDROGENATION CATALYST, INTRODUCING HYDROGEN THERTO TO MAINTAIN A PRESSURE OF FROM ABOUT 50 TO ABOUT 500 ATMOSPHERES IN SAID FIRST HYDROGENATION STAGE, SUBJECTING THE DIMETHYL TEREPHTHALATE IN SAID FIRS HYDROGENATION STAGE TO A PARTIAL HYDROGENATION AT A TEMPERATURE OF FROM ABOUT 100*C. TO ABOUT 400*C., WITHDRAWING A PORTION OF THE HYDROGEN FROM SAID FIRST HYDROGENATION STAGE, COOLING AND COMPRESSING SAID PORTION OF HYDROGEN, AND REINTRODUCING SAID PORTION OF HYDROGEN TO SAID FIRST HYDROGENATION STAGE, SAID PORTION OF REINTRODUCED INTO SAID FIRST HYDROGENATION STAGE AMOUNTING TO BETWEEN ABOUT 0.9 AND 1.8 LBS. OF HYDROGEN REINTRODUCED TO SAID FIRST HYDROGENATION STAGE PER POUND OF DIMETHYL TEREPHTHALATE INTRODUCED TO SAID FIRST HYDROGENATION STAGE, CONVEYING THE PARTIALLY HYDROGENATED DIMETHYL TEREPHTHALATE FROM SAID FIRST HYDROGENATION STAGE TO A SECOND HYDROGENATION STAGE, SAID SECOND HYDROGENATION STAGE CONTAINING A COPPER-CHROMITE HYDRO-

Claim 4

A PROCESS FOR THE CONTINUOUS HYDROGENATION OF DIMETHYL TEREPHTHALATE TO 1,4-CYCLOHEXANEDIMETHANOL WHICH COMPRISES INTRODUCING DIMETHYL TEREPHTHALATE TO A FIRST HYDROGENATION STAGE CONTAINING A PALLADIUM HYDROGENATION CATALYST, INTRODUCING HYDROGEN THERTO TO MAINTAIN A PRESSURE OF FROM ABOUT 50 TO ABOUT 500 ATMOSPHERES IN SAID FIRST HYDROGENATION STAGE, SUBJECTING THE DIMETHYL TEREPHTHALATE IN SAID FIRS HYDROGENATION STAGE TO A PARTIAL HYDROGENATION AT A TEMPERATURE OF FROM ABOUT 100*C. TO ABOUT 400*C., WITHDRAWING A PORTION OF THE HYDROGEN FROM SAID FIRST HYDROGENATION STAGE, COOLING AND COMPRESSING SAID PORTION OF HYDROGEN, AND REINTRODUCING SAID PORTION OF HYDROGEN TO SAID FIRST HYDROGENATION STAGE, SAID PORTION OF REINTRODUCED INTO SAID FIRST HYDROGENATION STAGE AMOUNTING TO BETWEEN ABOUT 0.9 AND 1.8 LBS. OF HYDROGEN REINTRODUCED TO SAID FIRST HYDROGENATION STAGE PER POUND OF DIMETHYL TEREPHTHALATE INTRODUCED TO SAID FIRST HYDROGENATION STAGE, CONVEYING THE PARTIALLY HYDROGENATED DIMETHYL TEREPHTHALATE FROM SAID FIRST HYDROGENATION STAGE TO A SECOND HYDROGENATION STAGE, SAID SECOND HYDROGENATION STAGE CONTAINING A COPPER-CHROMITE HYDRO-

Claim 5

THE PROCESS OF CLAIM 10 IN WHICH THE 1,4-CYCLOHEXANEDIMETHANOL FROM SAID SECOND HYDROGENATION STAGE IS SUBJECTED TO FLASH DISTILLATION TO REMOVE METHANOL AND WITHOUT FURTHER PURIFICATION IS PASSED TO POLYESTER MANUFACTURE.