Catalyst and method for the preparation thereof

Abstract

The invention relates to a noble metal catalyst for hydrocarbon conversion, to a method for the preparation thereof based on gas phase technique, to the use of the catalyst in reactions such as ring-opening, isomerisation, alkylation, hydrocarbon reforming, dry reforming, hydrogenation and dehydrogenation reactions, and to a method for the manufacture of middle distillates. Said noble metal catalyst comprises a group VIII metal selected from platinum, palladium, ruthenium, rhodium, iridium, or mixtures of combinations thereof on a support and the catalyst activates carbon monoxide at a temperature below 323 K.

1 . A method for the manufacture of a noble metal catalyst for hydrocarbon conversion, characterized in that the method comprises the following steps: 
 a) Pre-treatment of a support comprising a zeolite selected from medium and large pore zeolites having acid sites, at a temperature between 423-1173 K, and optional modification of the support;    b) Deposition of a noble metal selected from platinum, palladium, ruthenium, rhodium, iridium and mixtures and combinations thereof by gas phase deposition technique comprising vaporisation of the noble metal precursor selected from β-diketonates and metallocenes and reaction with the support, and    c) Heat treatment at oxidising or reducing conditions.    
     
     
         2 . The method according to  claim 1 , characterized in that the noble metal is platinum.  
     
     
         3 . The method according to  claim 1  or  2 , characterized in that the zeolite is selected from large pore zeolites having weak or medium strength of acid sites.  
     
     
         4 . The method according to  claim 1 , characterized in that the zeolite is selected from mesoporous aluminosilicates, crystalline aluminosilicates, crystalline aluminophosphates and crystalline aluminosilicophosphates.  
     
     
         5 . The method according to  claim 1 , characterized in that the zeolite is selected from MCM-41, Y- and beta-zeolites, mordenites, AlPO-5 and AlPO-11, SAPO-5 and SAPO-11.  
     
     
         6 . The method according to  claim 1 , characterized in that the support further comprises inorganic oxide, carbon related material or mixtures or combinations thereof.  
     
     
         7 . The method according to  claim 6 , characterized in that the inorganic oxide is selected from silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, tungsten oxide and magnesium oxide, preferably from silicon oxide and aluminum oxide.  
     
     
         8 . The method according to  claim 6 , characterized in that the carbon related material is selected from activated carbon, graphite and carbon nanotubes.  
     
     
         9 . The method according to  claim 1 , characterized in that the noble metal precursor is (CH 3 ) 3 (CH 3 C 5 H 4 )Pt.  
     
     
         10 . The method according to  claim 1 , characterized in that the zeolite is MCM-41.  
     
     
         11 . The method according to  claim 1 , characterized in that in the first process step a) the support is pre-treated at a temperature of 423-1173 K, and in the second step b) the deposition is carried out in the presence of an inert carrier gas.  
     
     
         12 . The method according to  claim 11 , characterized in that the inert carrier gas is nitrogen, helium, argon or methane.  
     
     
         13 . The method according to  claim 1 , characterized in that the modification in the first step a) is carried out by blocking part of available surface sites on the support with a blocking agent selected from alcohols, acetyl acetone, 2,2,6,6-tetramethyl-3,5-heptanedione, precursors of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, tungsten oxide and magnesium oxide, and nitrates.  
     
     
         14 . The method according to  claim 13 , characterized in that the blocking agent is silicon tetrachloride, tetramethoxysilane, tetraethoxysilane, hexamethyldisilazane, hexamethyldisiloxane, aluminum chloride, aluminum ethoxide, aluminum (III) acetylacetonate, tris(2,2,6,6,-tetramethyl-3,5-heptanedionato)aluminum, trimethyl aluminum, triethyl aluminum, titanium tetrachloride, titanium isopropoxide, zirconium tetrachloride, tungsten oxy-chloride, tungsten hexachloride or tris(2,2,6,6-tetramethyl-3,5-heptanedionato) magnesium.  
     
     
         15 . Use of the noble metal catalyst manufactured according to the method of  claim 1  in ring-opening, isomerisation, alkylation, hydrocarbon reforming, dry reforming, hydrogenation and dehydrogenation reactions, and preferably in ring-opening of naphthenic molecules.  
     
     
         16 . A process for the manufacture of middle distillate diesel fuel, characterized in that a middle distillate feedstock is transferred to a reactor wherein it is allowed to react at a temperature of 283-673 K and under a pressure of 10-200 bar with hydrogen in the presence of a noble metal catalyst manufactured according to the method of  claim 1  to accomplish opening of naphthenes with two and multiple rings to produce isoparaffins, n-paraffins and mononaphthenes in the middle distillate region.