Method for preparing acrolein from glycerol or glycerine

Abstract

The invention relates to a method for preparing acrolein from glycerol or glycerine, comprising dehydrating glycerol or glycerine in the presence of a catalyst consisting of at least a) a mixed oxide of zirconium and at least one metal, said metal being selected from niobium, tantalum and vanadium, b) a zirconium oxide and at least one metal oxide, the metal being selected from niobium, tantalum and vanadium, c) a silicon oxide and a mixed oxide of zirconium and at least one metal, the metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon, d) a silicon oxide and a mixed oxide of zirconium and at least one metal, the metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and titanium, e) a titanium oxide and a mixed oxide of zirconium and at least one metal, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon, f) a titanium oxide and a mixed oxide or zirconium and at least one metal, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon. The method can be used for producing -3-(methylthio)propionic (MMP) aldehyde, 2-hydroxy-4-methylthiobutyronitrile (HMTBN), methionine and analogues thereof from acrolein.

1 . A method for preparing acrolein from glycerol or glycerine, where dehydration of the glycerol or glycerine is achieved in the presence of a catalyst based on zirconium oxide and comprising:
 a) a mixed oxide of zirconium and of at least one metal M, said metal being selected from niobium, tantalum and vanadium,   b) a zirconium oxide and at least one metal M oxide, said metal being selected from niobium, tantalum and vanadium,   c) a silicon oxide, a mixed oxide of zirconium and of at least one metal M, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon,   d) a silicon oxide and a mixed oxide of zirconium and of at least one metal M, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and titanium,   e) a titanium oxide, a mixed oxide of zirconium and of at least one metal M, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon,   f) a titanium oxide and a mixed oxide of zirconium and of at least one metal M, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, titanium, vanadium and silicon.   
     
     
         2 . The method according to  claim 1 , wherein the catalyst comprises at least a) a mixed oxide of zirconium and of at least one metal M and b) a zirconium oxide and at least one metal M oxide. 
     
     
         3 . The method according to  claim 1 , wherein at least one of the oxides of said catalyst a) to f) is supported. 
     
     
         4 . The method according to  claim 1 , wherein the (Zr/sum of the elements Si, Ti and M, different from Zr) molar ratio varies from 0.5 to 200. 
     
     
         5 . The method according to  claim 4 , wherein said molar ratio varies from 1 to 100. 
     
     
         6 . The method according to any of  claim 1 , wherein the glycerol is in aqueous solution at a concentration of at least 1% by weight. 
     
     
         7 . The method according to  claim 6 , wherein the glycerol concentration of the aqueous solution varies from 10 to 50% by weight. 
     
     
         8 . The method according to  claim 1 , wherein the catalyst is regenerated. 
     
     
         9 . A method for making 3-(methylthio)propionic aldehyde MMP, 2-hydroxy-4-,methylthiobutyronitrile HMTBN, methionine, 2-hydroxy-4-methylthiobutanoic acid HMTBA, esters of the latter, or 2-oxo-methylthiobutanoic acid KMB, from acrolein, wherein the acrolein is obtained with a method according to  claim 1 . 
     
     
         10 . The method according to  claim 1 , wherein the hydration reaction is conducted in a gas phase. 
     
     
         11 . The method according to  claim 10 , wherein the dehydration reaction is conducted in a reactor with a fixed bed, a fluidized bed or a circulating fluidized bed. 
     
     
         12 . The method according to  claim 1 , wherein the dehydration reaction is conducted in a liquid phase. 
     
     
         13 . (canceled)