Abstract: Precipitated silica having large median particle size for use as reinforcing filler in elastomeric compositions as well as its method of manufacture. In particular, a precipitated silica characterised by a CTAB surface area SCTAB in the range from 70 to 350 m2/g; an amount WM of at least one metal M selected from elements of groups 3, 4 and 5 of at least 0.1 mol %; and a median particle size d50, measured by centrifugal sedimentation, such that: |d50|?183×|RION|×|WM|?0.67×|SCTAB|+233 (I) wherein |d50| represents the numerical value of median particle size d50 measured by centrifugal sedimentation and expressed in nm; |RION|, the numerical value of the ionic radius of metal M expressed in nm; |SCTAB|, the numerical value of the CTAB surface area SCTAB expressed in m2/g; and |WM|, the numerical value of the percentage molar amount of the metal WM.

Abstract: A method of preparing acrolein from glycerol or glycerine is disclosed. The method includes 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, or (b) a zirconium oxide and at least one metal oxide, the metal being selected from niobium, tantalum and vanadium, or (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, or (d) 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.

Abstract: The invention concerns a method for preparing acrolein from glycerol or glycerine, wherein dehydration of the glycerol or glycerine is achieved in the presence of a catalyst based on zirconium oxide and which active phase consists in at least a) a silicon oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and titanium, b) a titanium oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and silicon. This method can be used for making 3-(methylthio)propionic aldehyde MMP, 2-hydroxy-4-methylthiobutyronitrile HMTBN, methionine and its analogs.

Abstract: A method of preparing acrolein from glycerol or glycerine is disclosed. The method includes 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, or (b) a zirconium oxide and at least one metal oxide, the metal being selected from niobium, tantalum and vanadium, or (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, or (d) 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.

Abstract: The invention concerns a method for preparing acrolein from glycerol or glycerine, wherein dehydration of the glycerol or glycerine is achieved in the presence of a catalyst based on zirconium oxide and which active phase consists in at least a) a silicon oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and titanium, b) a titanium oxide, a zirconium oxide and at least one metal M oxide, said metal being selected from tungsten, cerium, manganese, niobium, tantalum, vanadium and silicon. This method can be used for making 3-(methylthio)propionic aldehyde MMP, 2-hydroxy-4-,methylthiobutyronitrile HMTBN, methionine and its analogs.

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 on