Ruthenium-based catalyst for producing lower polyhydric alcohols

Abstract

A ruthenium-based hydrogenation catalyst, particularly but not exclusively for hydrogenolysis under pressure of higher polyhydric alcohols, comprises ruthenium supported on granular activated carbon, and has:a specific surface area of from 600 to 1000 m2/g;a total pore volume of from 0.5 to 1.2 cm3/g;an apparent specific weight (bulk density) of from 0.45 to 0.55 g/cm3;an actual specific weight of from 1.9 to 2.3 g/cm3;a total volume of micropores having a radius smaller than 75 A of from 0.4 to 0.55 cm3/g; andan ash content of from 2 to 5% by weight.The catalyst is used in a method for the continuous production of lower polyhydric alcohols in a fixed bed reactor, by means of hydrogenolysis under pressure of higher polyhydric alcohols.

What is claimed is:  
     
       1. A method of producing a catalyst comprising from 0.5 to 5% by weight of ruthenium supported on granulated activated carbon useful for hydrogenolysis under pressure of higher polyhydric alcohols, wherein it comprises the steps of: 
       suspending granular activated carbon in water, the granular activated carbon having:  
       a specific surface area of from 600 to 1000 m 2 /g;  
       a total pore volume of from 0.5 to 1.2 cm 3 /g;  
       an apparent specific weight (bulk density) of from 0.45 to 0.55 g/cm 3 ;  
       an actual specific weight of from 1.9 to 2.3 g/cm 3 ;  
       a total volume of micropores having a radius smaller than 75 A of from 0.4 to 0.55 cm 3 /g; and  
       an ash content of from 2 to 5% by weight;  
       adding an aqueous ruthenium chloride solution to the suspension;  
       adjusting the pH of the suspension to a value of between 4.5 and 8 by adding an alkaline agent;  
       heating the suspension to a temperature of between 70° and 100° C. and maintaining the suspension at this temperature for a time of between 30 minutes and 2 hours;  
       separating the solid from the suspension by filtration;  
       re-suspending the solid in a solution of alkaline agent by heating the suspension to a temperature of between 60° and 100° C.;  
       reducing the catalyst obtained by bubbling a hydrogen flow into the suspension for a time of between 1 and 3 hours; and  
       separating the solid from the suspension.  
     
     
       2. A catalyst according to claim  1 , wherein it has a specific surface area of from 800 to 1000 m 2 /g and a total pore volume of from 0.6 to 0.7 cm 3 /g. 
     
     
       3. A catalyst produced according to claim  1 , wherein the catalyst has a particle-size distribution of 20-30% by weight of granules between 10 and 18 mesh (2.0-1.0 mm) and 80-70% by weight of granules between 18 and 35 mesh (1.0-0.5 mm). 
     
     
       4. A catalyst produced according to claim  1 . 
     
     
       5. A method of producing a catalyst comprising from 0.5 to 5% by weight of ruthenium supported on granulated activated carbon useful for hydrogenolysis under pressure of higher polyhydric alcohols, wherein it comprises the steps of: 
       (a) suspending granular activated carbon in water, the granular activated carbon having:  
       a specific surface area of from 600 to 1000 m 2 /g;  
       a total pore volume of from 0.5 to 1.2 cm 3 /g;  
       an apparent specific weight (bulk density) of from 0.45 to 0.55 g/cm 3 ;  
       an actual specific weight of from 1.9 to 2.3 g/cm 3 ;  
       a total volume of micropores having a radius smaller than 75 A of from 0.4 to 0.55 cm 3 /g; and  
       an ash content of from 2 to 5% by weight;  
       (b) adding an aqueous ruthenium chloride solution to the suspension;  
       (c) adjusting the pH of the suspension to a value of between 4.5 and 8 by adding an alkaline agent;  
       (d) heating the suspension to a temperature of between 70° and 100° C. and maintaining the suspension at this temperature for a time of between 30 minutes and 2 hours;  
       (e) separating the solid from the suspension by filtration;  
       (f) re-suspending the solid in a solution of alkaline agent by heating the suspension to a temperature of between 60° and 100° C.;  
       (g) reducing the catalyst obtained by bubbling a hydrogen flow into the suspension for a time of between 1 and 3 hours; and  
       (h) separating the solid from the suspension.  
     
     
       6. A catalyst produced according to claim  5 . 
     
     
       7. A method of producing a catalyst comprising from 1 to 3% by weight of ruthenium supported on granulated activated carbon, useful for hydrogenolysis under pressure of higher polyhydric alcohols, wherein it comprises the steps of: 
       (a) suspending granular activated carbon in water, the granular activated carbon having:  
       a specific surface area of from 600 to 1000 m 2 /g;  
       a total pore volume of from 0.5 to 1.2 cm 3 /g;  
       an apparent specific weight (bulk density) of from 0.45 to 0.55 g/cm 3 ;  
       an actual specific weight of from 1.9 to 2.3 g/cm 3 ;  
       a total volume of micropores having a radius smaller than 75 A of from 0.4 to 0.55 cm 3 /g; and  
       an ash content of from 2 to 5% by weight;  
       (b) adding an aqueous ruthenium chloride solution to the suspension;  
       (c) adjusting the pH of the suspension to a value of between 4.5 and 8 by adding an alkaline agent;  
       (d) heating the suspension to a temperature of between 70° and 100° C. and maintaining the suspension at this temperature for a time of between 30 minutes and 2 hours;  
       (e) separating the solid from the suspension by filtration;  
       (f) re-suspending the solid in a solution of alkaline agent by heating the suspension to a temperature of between 60° and 100° C.;  
       (g) reducing the catalyst obtained by bubbling a hydrogen flow into the suspension for a time of between 1 and 3 hours; and  
       (h) separating the solid from the suspension.  
     
     
       8. A catalyst produced according to claim  7 . 
     
     
       9. A catalyst comprising ruthenium in an amount from  0 . 5  to  5 %  by weight supported on active granulated carbon of vegetable origin, the catalyst being capable of catalyzing hydrogenolysis of higher polyhydric alcohols under pressure, the catalyst having:    
       ( a )  a specific surface area of from  600  to  1000  m   2   /g;    
       ( b )  a total pore volume of from  0 . 5  to  1 . 2  cm   3   /g;    
       ( c )  a total volume of micropores having a radius smaller than  75  Å of from  0 . 4  to  0 . 55  cm   3   /g; and    
       ( d )  an ash content of from  2  to  5   %  by weight.   
     
     
       10. A catalyst according to claim  9 , wherein: 
       ( a )  the specific surface area is between  800  and  1000  m   2   /g;    
       ( b )  the catalyst has an apparent specific weight  ( bulk density )  of from  0 . 45  to  0 . 55  g/cm   3 ;  
       ( c )  the catalyst has an actual specific weight of from  1 . 9  to  2 . 3  g/cm   3 . 
     
     
       11. A catalyst according to claim  9 , wherein the catalyst has a particle size distribution of  20 - 30 %  by weight of granules between  10  and  18  mesh  (   2 . 0  mm- 1 . 0  mm )  and  80   % - 70   %  by weight of granules between  18  and  35  mesh  (   1 . 0  mm and  0 . 5  mm ).