Polymer templated nanowire catalysts

Abstract

Nanowires useful as heterogeneous catalysts are provided. The nanowire catalysts are prepared by polymer templated methods and are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to ethane and/or ethylene. Related methods for use and manufacture of the same are also disclosed.

1 .- 33 . (canceled) 
     
     
         34 . A process for the preparation of ethylene from methane comprising contacting a mixture comprising oxygen and methane with a catalytic material comprising nanowires comprising a plurality of metal oxides (M x O y ), metal oxy-hydroxides (M x O y OH z ), metal oxycarbonates (M x O y (CO 3 ) z ) or metal carbonates (M x (CO 3 ) y ) or combinations thereof, the nanowires prepared by a method comprising:
 a) providing a solution comprising a polymer template; and   (b) introducing at least one metal ion and at least one anion to the solution under conditions and for a time sufficient to allow for nucleation and growth of nanowires comprising a plurality of metal salts (M m X n Z p ) on the polymer template,   wherein:   M is, at each occurrence, independently a metal element from any of Groups 1 through 7, lanthanides or actinides;   X is, at each occurrence, independently hydroxide, carbonate, bicarbonate, phosphate, hydrogenphosphate, dihydrogenphosphate, sulfate, nitrate or oxalate;   Z is O;   n, m, x and y are each independently a number from 1 to 100; and   p is a number from 0 to 100.   
     
     
         35 . The process of  claim 34 , wherein the polymer template is functionalized with at least one of amine, carboxylic acid, sulfate, alcohol or thiol groups. 
     
     
         36 . The process of  claim 35 , wherein the polymer template comprises a hydrocarbon polymer. 
     
     
         37 . The process of  claim 36 , wherein the polymer template comprises polystyrene. 
     
     
         38 . The process of  claim 34 , wherein the method further comprises converting the nanowires comprising the plurality of metal salts (M m X n Z p ) to the nanowires comprising the plurality of metal oxides (M x O y ), metal oxy-hydroxides (M x O y OH z ), metal oxycarbonates (M x O y (CO 3 ) z ), metal carbonate (M x (CO 3 ) y ) or combinations thereof. 
     
     
         39 . The process of  claim 34 , further comprising oligomerizing the ethylene to prepare a downstream product of ethylene. 
     
     
         40 . The process of  claim 34 , where the preparation of ethylene is carried out at a temperature below 900° C. 
     
     
         41 . The process of  claim 34 , where the catalytic material comprises the nanowires with a C2 selectivity of greater than 50%. 
     
     
         42 . The process of  claim 34 , where the catalytic material comprises the nanowires with a methane conversion of greater than 20%. 
     
     
         43 . The process of  claim 34 , where the preparation of ethylene is carried out at a pressure greater than 6 atmospheres. 
     
     
         44 . A process for the preparation of ethylene from methane comprising contacting a mixture comprising oxygen and methane with a catalytic material comprising nanowires having catalytic activity for oxidative coupling of methane, the nanowires prepared by a method comprising:
 preparing an aqueous mixture comprising (A), (B) and (C) by:
 admixing (A) with a mixture comprising (B) and (C); 
 admixing (B) with a mixture comprising (A) and (C); or 
 admixing (C) with a mixture comprising (A) and (B), 
   wherein (A), (B) and (C) comprise, respectively:
 (A) a polymer template; 
 (B) two or more metal salts comprising two or more metal elements selected from Groups 1 through 7, lanthanides and actinides thereof, wherein the two or more metal elements are independently different elements selected from Groups 1 through 7, lanthanides and actinides; and 
 (C) one or more anion precursors; and 
   nucleating and growing the nanowires on the polymer template in the aqueous mixture.   
     
     
         45 . The process of  claim 44 , wherein the polymer template is functionalized with at least one of amine, carboxylic acid, sulfate, alcohol or thiol groups. 
     
     
         46 . The process of  claim 45 , wherein the polymer template comprises a hydrocarbon polymer. 
     
     
         47 . the process of  claim 46 , wherein the polymer template comprises polystyrene. 
     
     
         48 . The process of  claim 44 , further comprising oligomerizing the ethylene to prepare a downstream product of ethylene. 
     
     
         49 . The process of  claim 44 , wherein the preparation of ethylene is carried out at a temperature below 900° C. 
     
     
         50 . The process of  claim 44 , wherein the catalytic material comprises the nanowires with a C2 selectivity of greater than 50%. 
     
     
         51 . The process of  claim 44 , wherein the catalytic material comprises the nanowires with a methane conversion of greater than 20%. 
     
     
         52 . The process of  claim 44 , wherein the preparation of ethylene is carried out at a pressure greater than 6 atmospheres. 
     
     
         53 . The process of  claim 44 , wherein the mixture comprising (B) and (C) is prepared by admixing (B) and (C), the mixture comprising (A) and (C) is prepared by admixing (A) and (C) or the mixture comprising (A) and (B) is prepared by admixing (A) and (B). 
     
     
         54 . The process of  claim 44 , wherein the two or more metal salts comprise chlorides, bromides, iodides, nitrates, sulfates, acetates, oxides, oxalates, oxyhalides, oxynitrates, phosphates, hydrogenphosphate, dihydrogenphosphate or mixtures thereof. 
     
     
         55 . The process of  claim 44 , wherein the two or more salts comprise MgCl 2 , LaCl 3 , ZrCl 4 , WCl 4 , MoCl 4 , MnCl 2  MnCl 3 , Mg(NO 3 ) 2 , La(NO 3 ) 3 , ZrOCl 2 , Mn(NO 3 ) 2 , Mn(NO 3 ) 3 , ZrO(NO 3 ) 2 , Zr(NO 3 ) 4  or mixtures thereof. 
     
     
         56 . The process of  claim 44 , wherein the metals in the two or more metal salts are independently different metals selected from Mg, Ca, Mg, W, La, Nd, Sm, Eu, W, Mn and Zr. 
     
     
         57 . The process of  claim 44 , wherein the one or more anion precursors comprise alkali metal hydroxides, alkaline earth metal hydroxides, carbonates, bicarbonates, ammonium hydroxides, or mixtures thereof. 
     
     
         58 . The process of  claim 44 , wherein the one or more anion precursors comprise LiOH, NaOH, KOH, Sr(OH) 2 , Ba(OH) 2 , Na 2 CO 3 , K 2 CO 3 , NaHCO 3 , KHCO 3 , and NR 4 OH, wherein R is selected from H, and C 1 -C 6  alkyl. 
     
     
         59 . The process of  claim 44 , wherein the polymer template comprises PVP (polyvinlpyrrolidone), PVA (polyvinylalcohol), PEI (polyethyleneimine), PEG (polyethyleneglycol), polyethers, polyesters, polyamides, dextran, sugar polymers, functionalized hydrocarbon polymers, functionalized polystyrene, polylactic acid, polycaprolactone, polyglycolic acid, poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) or copolymers or combinations thereof. 
     
     
         60 . The process of  claim 44 , wherein nucleating and growing the nanowires on the polymer template in the aqueous mixture comprises allowing the aqueous mixture comprising (A), (B) and (C) to stand at a temperature of from about 4° C. to about 80° C. for a period of time sufficient to allow nucleation of the nanowires. 
     
     
         61 . The process of  claim 44 , further comprising adding a doping element comprising metal elements, semi-metal elements, non-metal elements or combinations thereof to the aqueous mixture comprising (A), (B) and (C). 
     
     
         62 . The process of  claim 44 , further comprising calcining the nanowires. 
     
     
         63 . The process of  claim 62 , wherein calcining the nanowires comprises heating the nanowires at 450° C. or greater for at least 60 min.