Phosphorus modified molecular sieves, their use in conversion of organics to olefins

A process comprising:

• contacting an oxygen-containing, feedstock in a first reactor with a catalyst under conditions effective to convert the oxygen-containing feedstock to a first reactor effluent comprising olefin products, wherein the catalyst comprises a phosphorus modified zeolite having a P content ranging between 0.3 and 7 weight percent, wherein the phosphorus modified zeolite is made by a process comprising:
• selecting a zeolite having a Si:Al atomic ratio of 30 or less, wherein the zeolite is selected from the group consisting of MFI, MEL, FER, MOR, and clinoptilolite, and wherein the selected zeolite is in the H+ or NH4+ form;
• steaming the zeolite at a temperature ranging from 400° C. to 870° C. for 0.01 h to 200 h;
• leaching the zeolite with an aqueous acid solution containing a source of P at conditions effective to remove a substantial amount of Al from the zeolite and to introduce more than 0.3 wt % of P, wherein the aqueous acid solution containing the source of P comprises a salt of a phosphate ([PO4]3−), an acid or a corresponding salt of a phosphite ([HPO3]2−), an acid or a corresponding salt of a hypophosphite ([H2PO2]1−), an acid or a corresponding salt of a diphosphate, or an acid or a corresponding salt of a polyphosphate;
• separating the zeolite from the aqueous acid solution;
• and
• calcining the zeolite;
• wherein the first reactor effluent comprises light olefins and a heavy hydrocarbon fraction and is sent to a first fractionator to separate the light olefins from the heavy hydrocarbon fraction, and wherein a portion of the heavy hydrocarbon fraction is sent to a second reactor at conditions effective to convert at least a portion of the heavy hydrocarbon fraction to light olefins, wherein a catalyst in the second reactor is the same as the catalyst in the first reactor.