摘要:
Provided is an SCRF article having different SCR catalysts compositions disposed on a wall-flow filter substrate in zones that are arranged in series with respect to the inlet and outlet faces of the substrate. Also provided is method of reducing backpressure and ammonia slip that involves the use of such SCRF articles.
摘要:
A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and shown to be effective catalysts for dehydrocyclodimerization reactions. These zeolites are represented by the empirical formula. NanMmn+RrQqAl1-xExSiyOz where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,Ω-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting at least one aliphatic hydrocarbon having from 2 to about 6 carbon atoms per molecule with the coherently grown composites of TUN and IMF zeotypes to produce at least one aromatic hydrocarbon.
摘要:
Disclosed herein are processes for preparing an α,ω-Cn-diol, wherein n is 5 or greater, from a feedstock comprising a Cn oxygenate. In some embodiments, the process comprises contacting the feedstock with hydrogen gas in the presence of a catalyst comprising metals M1, M2, and M3 and optionally a support, wherein: M1 is Mn, Cr, V, or Ti; M2 is Ni, Co, or Fe; and M3 is Cu, Ag, Pt, Pd or Au; or M1 is Pt or Rh; M2 is Cu, Ni or Pd; and M3 is Mo, Re or W. The Cn oxygenate may be obtained from a biorenewable resource.
摘要:
A catalyst composition includes a heterobimetallic zeolite characterized by a chabazite structure loaded with copper ions and at least one trivalent metal ion other than Al3+. The catalyst composition decreases NOx emissions in diesel exhaust and is suitable for operation in a catalytic converter.
摘要:
A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.
摘要:
A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Ir and Pt.
摘要:
A heterogeneous catalyst article having at least one combination of a first molecular sieve having a medium pore, large pore, or meso-pore crystal structure and optionally containing a first metal, and a second molecular sieve having a small pore crystal structure and optionally containing a second metal, and a monolith substrate onto or within which said catalytic component is incorporated, wherein the combination of the first and second molecular sieves is a blend, a plurality of layers, and/or a plurality of zones.
摘要:
Provided is an SCRF article having different SCR catalysts compositions disposed on a wall-flow filter substrate in zones that are arranged in series with respect to the inlet and outlet faces of the substrate. Also provided is method of reducing backpressure and ammonia slip that involves the use of such SCRF articles.
摘要:
Provided is an emission treatment system and method for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The emission treatment system has an oxidation catalyst upstream of a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia. Also provided is a method for disposing an SCR catalyst composition on a wall flow monolith that provides adequate catalyst loading, but does not result in unsuitable back pressures in the exhaust.
摘要:
A method of using a catalyst comprises exposing a catalyst to at least one reactant in a chemical process. The catalyst comprises copper and a small pore molecular sieve having a maximum ring size of eight tetrahedral atoms. The chemical process undergoes at least one period of exposure to a reducing atmosphere. The catalyst has an initial activity and the catalyst has a final activity after the at least one period of exposure to the reducing atmosphere. The final activity is within 30% of the initial activity at a temperature between 200 and 500° C.