Process And Catalysts For The Opening Of Naphthene Rings

Abstract

A process is described for the upgrading of distillates having a boiling point ranging from 100 to 450° C., which comprises the opening of the ring of the naphthene compounds contained in these distillates to obtain paraffinic compounds, rich in branched paraffins, having for the most part the same number of carbon atoms as the starting naphthene. The process is carried out in the presence of a bifunctional catalytic system comprising one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re, and a silico-aluminate of an acidic nature, selected from a micromesoporous silico-alumina and a zeolite belonging to the MTW group.

1 ) A process for the upgrading of distillates having a boiling point which varies from 100 to 450° C., by the opening of naphthene rings of compounds containing them to give paraffinic mixtures, said process consisting in treating the distillates, in the presence of hydrogen, with a catalytic system comprising: 
 a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re    b) a silico-aluminate of an acidic nature selected from a zeolite belonging to the MTW group and a completely amorphous, micro-mesoporous silico-alumina, having a molar ratio SiO 2 /Al 2 O 3  ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume within the range of 0.3-1.3 ml/g, an average pore diameter of less than 40 Å.    
     
     
         2 ) The process according to  claim 1 , wherein the acidic component (b) is a ZSM-12 zeolite.  
     
     
         3 ) The process according to  claim 1 , wherein the acidic component (b) is a silico-alumina with an SiO 2 /Al 2 O 3  molar ratio ranging from 50/1 to 300/1.  
     
     
         4 ) The process according to  claim 1 , wherein the acidic component (b) is a silico-alumina with a porosity ranging from 0.4 to 0.5 ml/g.  
     
     
         5 ) The process according to  claim 1 , wherein the acidic component (b) is a silico-alumina whose XRD spectrum from powders does not have a crystalline structure and does not show any peak.  
     
     
         6 ) The process according to  claim 1 , wherein the metal is platinum, iridium or mixtures thereof.  
     
     
         7 ) The process according to  claim 1 , wherein the metal or mixture of metals is in a quantity ranging from 0.1 to 5% by weight with respect to the total weight of the catalytic composition.  
     
     
         8 ) The process according to  claim 7 , wherein the metal or mixture of metals is in a quantity ranging from 0.3 to 1.5% by weight with respect to the total weight of the catalytic composition.  
     
     
         9 ) The process according to  claim 1 , wherein the distillates are hydrocarbon cuts selected from naphthas, diesel, kerosene, jet fuel, light cycle oil, HVGO, FCC heavy fraction.  
     
     
         10 ) The process according to  claim 1 , carried out at a temperature ranging from 240 to 380° C., at a pressure ranging from 20 to 70 atm, a WHSV ranging from 0.5 to 2 hours −1  and a hydrogen/charge ratio (H 2 /HC) ranging from 400 to 2000 Nlt/kg.  
     
     
         11 ) The process according to  claim 10 , wherein the acidic component (b) is a zeolite of the MTW type, the pressure is greater than 40 atm and less than or equal to 70 atm, and the temperature ranges from 240 to 320° C.  
     
     
         12 ) The process according to  claim 10 , wherein the acidic component (b) is a silico-alumina, the pressure is greater than 40 atm and less than or equal to 70 atm, and the temperature ranges from 300 to 380° C.  
     
     
         13 ) A catalytic composition comprising: 
 a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re    b) a zeolite belonging to the MTW group.    
     
     
         14 ) A catalytic composition comprising: 
 a) one or more metals selected from Pt, Pd, Ir, Ru, Rh and Re    b) a completely amorphous, micro-mesoporous silico-alumina, having a molar ratio SiO 2 /Al 2 O 3  ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume greater than 0.6 and less than or equal to 1.3 ml/g, an average pore diameter of less than 40 Å, an XRD spectrum from powders which does not have a crystalline structure and does not show any peak.    
     
     
         15 ) A catalytic composition comprising: 
 a) one or more metals selected from Ir, Ru, and Rh    b) a completely amorphous, micro-mesoporous silico-alumina, having a molar ratio SiO 2 /Al 2 O 3  ranging from 30 to 500, a surface area greater than 500 m 2 /g, a pore volume within the range of 0.3 and 1.3 ml/g, an average pore diameter of less than 40 Å, an XRD spectrum from powders which does not have a crystalline structure and does not show any peak.    
     
     
         16 ) A process for preparing the catalytic compositions of  claim 13 ,  14 ,  15 , which comprises subjecting the acidic component (b) to impregnation or ion exchange with a solution of a compound of one or more metals selected from Pt, Pd, Ir, Rh and Re.