Catalysts and methods for natural gas processes

Abstract

Catalysts and catalytic methods are provided. The catalysts and methods are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane.

1 . A catalyst comprising the following formula (IA):
   A x B y C v D w O z    (IA)
   wherein:   A is a lanthanide or group 4 element;   B is a group 2 element;   C is a group 13 element;   D is a lanthanide element;   O is oxygen;   v and w are independently numbers greater than 0;   x, y and z are independently numbers greater than 0, and v, w, x, y and z are selected such that A x B y C v D w O z  has an overall charge of 0.   
     
     
         2 . The catalyst of  claim 1 , wherein A is a lanthanide. 
     
     
         3 . The catalyst of  claim 2 , wherein A is lanthanum, cerium, praseodymium or neodymium. 
     
     
         4 . The catalyst of  claim 1 , wherein A is a Group 4 element. 
     
     
         5 . The catalyst of  claim 4 , wherein A is titanium, zirconium or hafnium. 
     
     
         6 . The catalyst of  claim 1 , wherein B is magnesium, calcium, strontium or barium. 
     
     
         7 . The catalyst of  claim 1 , wherein A is lanthanum and B is strontium, A is cerium and B is barium, A is praseodymium and B is barium, A is cerium and B is strontium, A is titanium and B is barium, A is titanium and B is strontium or A is titanium and B is calcium. 
     
     
         8 . The catalyst of  claim 1 , wherein C is aluminum, gallium, indium or thallium. 
     
     
         9 . The catalyst of  claim 1 , wherein D is lanthanum, neodymium, gadolinium or ytterbium. 
     
     
         10 . The catalyst of  claim 1 , wherein:
 A is titanium, zirconium or cerium;   B is calcium, strontium or barium;   C is aluminum, gallium or indium; and   D is lanthanum, neodymium; gadolinium or ytterbium.   
     
     
         11 . The catalyst of  claim 1 , comprising one of the following formulas: Ce x Ba y In v Nd w O 3 ; Ti x Ca y In v La w O 3 ; Ti x Ca y In v Nd w O 3 ; Ti x Ca y In v Gd w O 3 ; Ti x Ca y In v Yb w O 3 ; Zr x Ca y In v La w O 3 ; Zr x Ca y In v Nd w O 3 ; Zr x Ca y In v Gd w O 3 ; Zr x Ca y In v Yb w O 3 ; Ce x Ca y In v La w O 3 ; Zr x Ca y In v Nd w O 3 ; Zr x Ca y In v Gd w O 3 ; Zr x Ca y In v Yb w O 3 ; Ti x Sr y In v La w O 3 ; Ti x Sr y In v Nd w O 3 ; Ti x Sr y In v Gd w O 3 ; Ti x Sr y In v Yb w O 3 ; Zr x Sr y In v La w O 3 ; Zr x Sr y In v Nd w O 3 ; Zr x Sr y In v Gd w O 3 ; Zr x Sr y In v Yb w O 3 ; Ce x Sr y In v La w O 3 ; Ce x Sr y In v Nd w O 3 ; Ce x Sr y In v Gd w O 3 ; Ce x Sr y In v Yb w O 3 ; Ti x Ba y In v La w O 3 ; Ti x Ba y In v Nd w O 3 ; Ti x Ba y In v Gd w O 3 ; Ti x Ba y In v Yb w O 3 ; Zr x Ba y In v La w O 3 ; Zr x Ba y In v Nd w O 3 ; Zr x Ba y In v Gd w O 3 ; Zr x Ba y In v Yb w O 3 ; Ce x Ba y In v La w O 3 ; Ce x Ba y In v Nd w O 3 ; Ce x Ba y In v Gd w O 3  or Ce x Ba y In v Yb w O 3 . 
     
     
         12 . The catalyst of  claim 1 , wherein z is 3. 
     
     
         13 . The catalyst of  claim 1 , wherein the sum of v, w, x and y is 2. 
     
     
         14 . The catalyst of  claim 1 , wherein v and w each independently range from about 0.1 to about 0.6. 
     
     
         15 . The catalyst of  claim 1 , wherein x ranges from about 0.2 to about 0.8. 
     
     
         16 . The catalyst of  claim 1 , wherein y ranges from about 0.4 to about 1.0. 
     
     
         17 . The catalyst of  claim 1 , wherein v ranges from about 0.25 to about 0.45, w ranges from about 0.4 to about 0.6, x ranges from about 0.3 to about 0.5 and y ranges from about 0.6 to about 1.0. 
     
     
         18 . The catalyst of  claim 1 , wherein the catalyst is a nanostructured catalyst. 
     
     
         19 . The catalyst of  claim 18 , wherein the catalyst is a nanowire. 
     
     
         20 . The catalyst of  claim 1 , wherein the catalyst is a bulk catalyst. 
     
     
         21 . The catalyst of  claim 1 , in combination with a diluent or support. 
     
     
         22 . A formed catalytic material comprising the catalyst of  claim 1 . 
     
     
         23 . The formed catalytic material of  claim 22 , wherein the formed catalytic material is an extrudate or a tableted catalytic material. 
     
     
         24 . (canceled) 
     
     
         25 . The catalyst of  claim 1 , wherein a C2+ selectivity of the catalyst in an oxidative couple of methane (OCM) reaction is greater than about 50% when the OCM reaction is conducted at temperatures of about 700° C. or lower. 
     
     
         26 . The catalyst of  claim 1 , wherein the catalyst has a catalytic activity to achieve a methane conversion of greater than 10% and a C2+ selectivity of greater than 50% in an oxidative coupling of methane (OCM) reaction when the catalyst contacted with methane at temperatures of about 700° C. or lower. 
     
     
         27 . A method for the oxidative coupling of methane, the method comprising contacting methane with the catalyst of  claim 1 , thereby converting the methane to C2 hydrocarbons, C2+ hydrocarbons, or combinations thereof. 
     
     
         28 . (canceled) 
     
     
         29 . A method for performing the oxidative coupling of methane, the method comprising flowing a gas comprising methane from a front end to a back end of a catalyst bed comprising an OCM active catalyst, the catalyst bed having a total length L and a total OCM active catalyst surface area, wherein greater than 50% of the total OCM active catalyst surface area resides in a portion of the catalyst bed ranging from the front end to a distance equal to 50% of L. 
     
     
         30 - 37 . (canceled) 
     
     
         38 . A catalyst bed comprising a front end, a back end and an OCM active catalyst, the catalyst bed having a total length L and a total OCM active catalyst surface area, wherein greater than 50% of the total OCM active surface area resides in a portion of the catalyst bed ranging from the front end to a distance equal to 50% of L. 
     
     
         39 . A formed catalytic material comprising first and second OCM active catalysts, wherein the first OCM active catalyst is a nanostructured catalyst having a BET surface area of greater than 5 m 2 /g, and the second OCM active catalyst is a catalyst having a BET surface area of less than 2 m 2 /g, and wherein the catalytic material has a volume loss of less than 20% when heated to 900° C. in air for 100 hours. 
     
     
         40 - 50 . (canceled) 
     
     
         51 . A method for preparing a formed catalytic material, the method comprising:
 i) providing a first nanostructured OCM active catalyst having a BET surface area of greater than 5 m 2 /g;   ii) sintering the first nanostructured OCM active catalyst at a temperature above 1000° C. to obtain a second OCM active catalyst having a BET surface area of less than 2 m 2 /g;   iii) admixing the first and second OCM active catalysts; and   iv) forming the mixture to obtain the formed catalytic material.   
     
     
         52 - 64 . (canceled)