Method for oxidatively dehydrogenating alkanes

Abstract

A nanotherapeutic supported by a hierarchical silica composite with dual imaging capability (e.g. fluorescence and magnetic resonance imaging), a method of preparing the nanotherapeutic, and a method of treating cancer. Also disclosed is a method of oxidatively dehydrogenating ethane using a catalytic system supported by a hierarchical silica composite.

1 . (canceled) 
     
     
         2 . The method of  claim 13 , wherein the hierarchical silica composite has a silicon to aluminum molar ratio in a range of 1,000:1 to 3,000:1. 
     
     
         3 . The method of  claim 13 , wherein the mesopores in the catalyst have a pore volume in the range of 0.9-1.5 cm 3 /g and a surface area in the range of 1,000-1,600 m 2 /g. 
     
     
         4 - 12 . (canceled) 
     
     
         13 . A method of oxidatively dehydrogenating an alkane to form an olefin, comprising:
 contacting the alkane with a catalyst, an oxidant, and an inert gas in a reactor to oxidatively dehydrogenate the alkane to the olefin;   wherein the catalyst comprises:
 a hierarchical silica composite; and 
 an active catalytic material impregnated on the hierarchical silica composite, the active catalytic material comprising
 nickel, nickel oxide, and/or nickel and iron mixed metal oxide, and 
 at least one cation dopant selected from the group consisting of Nb 5+ , Al 3+ , Ti 4+ , Ta 5+ , and Bi 5+  and/or oxides thereof; 
 
 wherein the hierarchical silica composite is a stereoregular MCM-41 ordered arrangement of uniformly-sized mesopores with diameters in a range of 10-50 nm and mesopore walls having a thickness of 3 to about 5 nm; 
 a stereoregular ZSM-5 ordered arrangement of uniformly-sized micropores with diameters of less than 2 nm located within the mesopore walls of the stereoregular MCM-41; and 
 wherein the hierarchical silica composite has a silane coating that coats at least a portion of a surface of the hierarchical silica composite, 
 wherein the active catalytic material is incorporated into a lattice of the hierarchical silica composite by isomorphous substitution, 
 wherein the dopant is located inside the mesopores of the hierarchical silica composite, 
 wherein an amount of the dopant is in a range of 10-20 wt. %, 
 wherein an amount of the hierarchical silica composite is in a range of 15-70 wt. %, and 
 wherein an amount of the active catalytic material is in a range of 5-7.5 wt. %, all of which are relative to the total weight of the catalyst. 
   
     
     
         14 . (canceled) 
     
     
         15 . The method of  claim 13 , wherein the alkane is contacted with the catalyst, the oxidant and the inert gas at a pressure of 70-130 kPa, and a temperature of 450-700° C. 
     
     
         16 . The method of  claim 13 , further comprising:
 flowing the inert gas through the reactor at a flow rate of 50-150 mL min −1 , and flowing the alkane through the reactor at a flow rate of 0.5-1.0 mmol min −1 .   
     
     
         17 . The method of  claim 13 , further comprising:
 pre-treating the catalyst with an inert gas at an inert gas flow rate of 50-150 mL min −1  and a temperature of 450-700° C. for 0.5-2 hours.   
     
     
         18 . The method of  claim 13 , wherein the oxidant is O 2  and/or CO 2 , and the inert gas is He. 
     
     
         19 . The method of  claim 13 , wherein the alkane comprises ethane, and the olefin comprises ethylene. 
     
     
         20 . (canceled)