Fractionation process using zeolitic molecular sieves

Claim 1

THE PROCESS FOR TREATING A PLURALITY OF HYDROCARBON MIXTURES HAVING DIFFERENT BOILING RANGES WITHIN THE GASOLINE BOILING RANGE, EACH OF SAID MIXTURES COMPRISING STRAIGHT CHAIN AND NON-STRAIGHT CHAIN HYDROCARGONS, WHICH PROCESS COMPRISES, (1) CONTACTING THE LOWEST BOILING OF SAID MIXTURES WITH A SOLID GRANULAR ADSORBENT CONSISTING ESSENTIALLY OF A PARTIALLY DEHYDRATED ZEOLITIC METALLO ALUMINO SILICATE HAVING SUBSTANTIALLY UNIFORM INTRACRYSTALLINE PORES OF ABOUT 5 A. IN DIAMETER AND HAVING ADSORBED THEREON AT LEAST ONE STRAIGHT CHAIN HYDROCARBON BOILING OUTSIDE THE BOILING RANGE OF SAID LOWEST BOILING MIXTURE, WHEREBY SAID ADSORBED STRAIGHT CHAIN HYDROCARBON IS DESORBED AND THE STRAIGHT CHAIN COMPONENTS OF SAID LOWEST BOILING MIXTURE ARE ADSROBED, AND THERE IS OBTAINED A RAFFINATE PRODUCT COMPRISING SAID DESORBED STRAIGHT CHAIN HYDROCARBON AND THE NON-STRAIGHT CHAIN COMPONENTS OF SAID LOWEST BOILING MIXTURS, (2) SEPARATING SAID RAFFINATE PRODUCT FROM THE ADSORBENT, (3) REPEATING SAID STEPS (1) AND (2) AT LEAST ONCE IN SEQUENCE, THE HYDROCARBON MIXTURE EMPLOYED IN EACH REPEATED CONTACTING STEP HAVING A BOILING RANGE HIGHER THAN THAT OF THE MIXTURE EMPLOYED IN THE PRECEDING CONTACTING STEP, (4) SUBSEQUENT TO THE FINAL REPETITION OF SAID STEP (2), CONTACTING THE ADSORBENT WITH A DISPLACEMENT EXCHANGE FLUID COMPRISING STRAIGHT CHAIN HYDROCARGONS OF A BOILING RANGE LOWER THAN THAT OF THE STRAIGHT CHAIN HYDROCARBONS ADSORBED ON THE ADSORBENT, WHEREBY THE LATTER ARE DESORBED AND SAID STRAIGHT CHAIN HYDROCARBONS OF LOWER BOILING RANGE ARE AT LEAST PARTIALLY ADSORBED, AND THERE IS OBTAINED AN EXTRACT PRODUCT COMPRISING SAID DESORBED STRAIGHT CHAIN HYDROCARBONS AND ANY UNADSORBED COMPONENTS OF SAID DISPLACEMENT EXCHANGE FLUID, (5) SEPARATING SAID EXTRACT PRODUCT FROM THE ADSORBENT, (6) REPEATING SAID STEPS (4) AND (5) AT LEAST ONCE IN SEQUENCE, (7) TREATING SAID RAFFINATE PRODUCTS TO SEPARATE THE STRAIGHT CHAIN COMPONENTS THEREFROM, AND (8) TREATING SAID EXTRACT PRODUCTS TO SEPARATE THE DESORBED STRAIGHT CHAIN HYDROCARBON COMPONENTS THEREFROM.