Oxidation catalyst and process

Abstract

An oxidation catalyst is prepared by pyrolyzing a source of iron and a source of nitrogen on a carbon support. Preferably, a noble metal is deposited over the modified support which comprises iron and nitrogen bound to the carbon support. The catalyst is effective for oxidation reactions such as the oxidative cleavage of tertiary amines to produce secondary amines, especially the oxidation of N-(phosphonomethyl)iminodiacetic acid to N-(phosphonomethyl)-glycine.

1 . An oxidation catalyst comprising a particulate carbon support having a transition metal/nitrogen composition thereon, said transition metal being selected from the group consisting of iron and cobalt, wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride, an iron or cobalt nitride-carbide, or combinations thereof, and the nitrogen of said transition metal/nitrogen composition constitutes from about 1% to about 5% by weight of said catalyst.  
     
     
         2 . An oxidation catalyst as set forth in  claim 1  comprising said transition metal/nitrogen composition in such proportion that said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes at least about 0.1% by weight of said catalyst.  
     
     
         3 . An oxidation catalyst as set forth in  claim 2  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.1% to about 10% by weight of said catalyst.  
     
     
         4 . An oxidation catalyst as set forth in  claim 3  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.25% to about 7% by weight of said catalyst.  
     
     
         5 . An oxidation catalyst as set forth in  claim 4  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.5% to about 5% by weight of said catalyst.  
     
     
         6 . An oxidation catalyst as set forth in  claim 1  wherein the atomic ratio of transition metal to nitrogen in said transition metal/nitrogen composition is from about 1:4 to about 3:1.  
     
     
         7 . An oxidation catalyst as set forth in  claim 1  wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride.  
     
     
         8 . An oxidation catalyst as set forth in  claim 7  wherein said transition metal/nitrogen composition comprises ξ—Fe 3 N.  
     
     
         9 . An oxidation catalyst as set forth in  claim 8  wherein said transition metal/nitrogen composition further comprises an iron species selected from the group consisting of iron oxides, iron carbides, and metallic iron.  
     
     
         10 . An oxidation catalyst as set forth in  claim 7  wherein said transition metal/nitrogen composition comprises an iron nitride and superparamagnetic iron.  
     
     
         11 . An oxidation catalyst as set forth in  claim 10  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra comprises from about 30% to about 70% by weight ξ—Fe 3 N and from about 5% to about 20% by weight superparamagnetic iron.  
     
     
         12 . An oxidation catalyst as set forth in  claim 11  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra further comprises an additional iron species selected from α-iron, isolated iron atoms and mixtures thereof.  
     
     
         13 . An oxidation catalyst as set forth in  claim 12  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra comprises from about 15% to about 25% by weight α-iron, and from about 10% to about 20% by weight isolated iron atoms.  
     
     
         14 . An oxidation catalyst as set forth in  claim 1  wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride-carbide.  
     
     
         15 . An oxidation catalyst as set forth in  claim 1  wherein said transition metal/nitrogen composition is fixed to the carbon support.  
     
     
         16 . An oxidation catalyst as set forth in  claim 1  wherein said transition metal/nitrogen composition comprises an active phase for the catalysis of a redox reaction.  
     
     
         17 . An oxidation catalyst as set forth in  claim 16  wherein said active phase is effective for catalyzing the reduction of molecular oxygen.  
     
     
         18 . An oxidation catalyst as set forth in  claim 1  wherein at least about 95% of the particles of said carbon support are from about 2 to about 300 μm in their largest dimension.  
     
     
         19 . An oxidation catalyst as set forth in  claim 18  wherein at least about 98% of the particles of said carbon support are from about 2 to about 200 μm in their largest dimension.  
     
     
         20 . An oxidation catalyst as set forth in  claim 19  wherein about 99% of the particles of said carbon support are from about 2 to about 150 μm in their largest dimension.  
     
     
         21 . An oxidation catalyst as set forth in  claim 20  wherein about 95% of the particles of said carbon support are from about 3 to about 100 μm in their largest dimension.  
     
     
         22 . An oxidation catalyst as set forth in  claim 1  wherein said carbon support has a BET surface area of from about 500 to about 2100 m 2 /g.  
     
     
         23 . An oxidation catalyst as set forth in  claim 22  wherein said carbon support has a BET surface area of from about 750 to about 2100 m 2 /g.  
     
     
         24 . An oxidation catalyst as set forth in  claim 23  wherein said carbon support has a BET surface area of from about 750 to about 1750 m 2 /g.  
     
     
         25 . An oxidation catalyst as set forth in  claim 1  wherein said particulate carbon support is porous and said transition metal/nitrogen composition is substantially evenly distributed throughout the carbon particle.  
     
     
         26 . An oxidation catalyst as set forth in  claim 1  wherein said carbon support has a pore volume of from about 0.1 to about 2.5 ml per gram of catalyst.  
     
     
         27 . An oxidation catalyst as set forth in  claim 26  wherein said carbon support has a pore volume of from about 0.2 to about 2.0 ml per gram of catalyst.  
     
     
         28 . An oxidation catalyst as set forth in  claim 27  wherein said carbon support has a pore volume of from about 0.4 to about 1.7 ml per gram of catalyst.  
     
     
         29 . An oxidation catalyst as set forth in  claim 1  further comprising a noble metal at a surface of said particulate carbon support having said transition metal/nitrogen composition thereon.  
     
     
         30 . An oxidation catalyst as set forth in  claim 29  wherein said noble metal is selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, and combinations thereof.  
     
     
         31 . An oxidation catalyst comprising a particulate carbon support having a transition metal/nitrogen composition thereon, said transition metal being selected from the group consisting of iron and cobalt, wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride, an iron or cobalt nitride-carbide or combinations thereof, the nitrogen of said transition metal/nitrogen composition constitutes from about 0.1% to about 7% by weight of said catalyst, and said particulate carbon support has a BET surface area of from about 500 to about 2100 m 2 /g.  
     
     
         32 . An oxidation catalyst as set forth in  claim 31  comprising said transition metal/nitrogen composition in such proportion that said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes at least about 0.1% by weight of said catalyst.  
     
     
         33 . An oxidation catalyst as set forth in  claim 32  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.1% to about 10% by weight of said catalyst.  
     
     
         34 . An oxidation catalyst as set forth in  claim 33  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.25% to about 7% by weight of said catalyst.  
     
     
         35 . An oxidation catalyst as set forth in  claim 34  wherein said Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.5% to about 5% by weight of said catalyst.  
     
     
         36 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition is present in such proportion that the Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.5% to about 5% by weight of said catalyst, and the nitrogen of said transition metal/nitrogen composition constitutes from about 1% to about 5% by weight of said catalyst.  
     
     
         37 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition is present in such proportion that the Fe, Co or the sum of (Fe+Co) of said transition metal/nitrogen composition constitutes from about 0.2% to about 3% by weight of said catalyst, and the nitrogen of said transition metal/nitrogen composition constitutes from about 0.2% to about 3% by weight of said catalyst.  
     
     
         38 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition constitutes at least about 0.2% by weight of said catalyst.  
     
     
         39 . An oxidation catalyst as set forth in  claim 38  wherein said transition metal/nitrogen composition constitutes from about 0.4% to about 15% by weight of said catalyst.  
     
     
         40 . An oxidation catalyst as set forth in  claim 39  wherein said transition metal/nitrogen composition constitutes from about 0.4% to about 6% by weight of said catalyst.  
     
     
         41 . An oxidation catalyst as set forth in  claim 31  wherein the atomic ratio of transition metal to nitrogen in said transition metal/nitrogen composition is from about 1:4 to about 3:1.  
     
     
         42 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride.  
     
     
         43 . An oxidation catalyst as set forth in  claim 42  wherein said iron or cobalt nitride constitutes at least about 0.2% by weight of said catalyst.  
     
     
         44 . An oxidation catalyst as set forth in  claim 42  wherein said iron or cobalt nitride constitutes from about 0.4% to about 6% by weight of said catalyst.  
     
     
         45 . An oxidation catalyst as set forth in  claim 42  wherein said transition metal/nitrogen composition comprises ξ—Fe 3 N.  
     
     
         46 . An oxidation catalyst as set forth in  claim 45  wherein said transition metal/nitrogen composition further comprises an iron species selected from the group consisting of iron oxides, iron carbides, and metallic iron.  
     
     
         47 . An oxidation catalyst as set forth in  claim 42  wherein said transition metal/nitrogen composition comprises an iron nitride and superparamagnetic iron.  
     
     
         48 . An oxidation catalyst as set forth in  claim 47  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra comprises from about 30% to about 70% by weight ξ—Fe 3 N and from about 5% to about 20% by weight superparamagnetic iron.  
     
     
         49 . An oxidation catalyst as set forth in  claim 48  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra further comprises an additional iron species selected from α-iron, isolated iron atoms and mixtures thereof.  
     
     
         50 . An oxidation catalyst as set forth in  claim 49  wherein said transition metal/nitrogen composition as determined from Mössbauer spectra comprises from about 15% to about 25% by weight α-iron, and from about 10% to about 20% by weight isolated iron atoms.  
     
     
         51 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition comprises an iron or cobalt nitride-carbide.  
     
     
         52 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition is fixed to the carbon support.  
     
     
         53 . An oxidation catalyst as set forth in  claim 31  wherein said transition metal/nitrogen composition comprises an active phase for the catalysis of a redox reaction.  
     
     
         54 . An oxidation catalyst as set forth in  claim 53  wherein said active phase is effective for catalyzing the reduction of molecular oxygen.  
     
     
         55 . An oxidation catalyst as set forth in  claim 31  wherein at least about 95% of the particles of said carbon support are from about 2 to about 300 μm in their largest dimension.  
     
     
         56 . An oxidation catalyst as set forth in  claim 55  wherein at least about 98% of the particles of said carbon support are from about 2 to about 200 μm in their largest dimension.  
     
     
         57 . An oxidation catalyst as set forth in  claim 56  wherein about 99% of the particles of said carbon support are from about 2 to about 150 μm in their largest dimension.  
     
     
         58 . An oxidation catalyst as set forth in  claim 57  wherein about 95% of the particles of said carbon support are from about 3 to about 100 μm in their largest dimension.  
     
     
         59 . An oxidation catalyst as set forth in  claim 31  wherein said carbon support has a BET surface area of from about 750 to about 2100 m 2 /g.  
     
     
         60 . An oxidation catalyst as set forth in  claim 59  wherein said carbon support has a BET surface area of from about 750 to about 1750 m 2 /g.  
     
     
         61 . An oxidation catalyst as set forth in  claim 31  wherein said particulate carbon support is porous and said transition metal/nitrogen composition is substantially evenly distributed throughout the carbon particle.  
     
     
         62 . An oxidation catalyst as set forth in  claim 31  wherein said carbon support has a pore volume of from about 0.1 to about 2.5 ml per gram of catalyst.  
     
     
         63 . An oxidation catalyst as set forth in  claim 62  wherein said carbon support has a pore volume of from about 0.2 to about 2.0 ml per gram of catalyst.  
     
     
         64 . An oxidation catalyst as set forth in  claim 63  wherein said carbon support has a pore volume of from about 0.4 to about 1.7 ml per gram of catalyst.  
     
     
         65 . An oxidation catalyst as set forth in  claim 31  further comprising a noble metal at a surface of said particulate carbon support having said transition metal/nitrogen composition thereon.  
     
     
         66 . An oxidation catalyst as set forth in  claim 65  wherein said noble metal is selected from the group consisting of platinum, palladium, rhodium, iridium, osmium, ruthenium, and combinations thereof.