Nitrided mixed oxide catalyst system and a process for the production of ethylenically unsaturated carboxylic acids or esters
A method of producing an ethylenically unsaturated carboxylic acid or ester, preferably an α, β ethylenically unsaturated carboxylic acid or ester. The method includes contacting formaldehyde or a suitable source thereof with a carboxylic acid or ester in the presence of a catalyst and optionally in the presence of an alcohol. The catalyst includes a nitrided metal oxide having at least two types of metal cations, M 1 and M 2 , wherein M 1 is selected from the metals of group 2, 3, 4, 13 (called also IIIA) or 14 (called also IVA) of the periodic table and M2 is selected from the metals of groups 5 or 15 (called also VA) of the periodic table.
1. A method of producing an ethylenically unsaturated carboxylic acid or ester comprising the steps of contacting formaldehyde or a source thereof with a carboxylic acid or ester of formula R 3 —CH 2 —COOR 4 wherein R 4 is either hydrogen or an alkyl group and R 3 is either hydrogen, an alkyl or an aryl group, in the presence of a catalyst and optionally in the presence of an alcohol, wherein the catalyst comprises a nitrided metal oxide having at least two metal cations, M 1 and M 2 , wherein:
the M 1 type of metal is selected from one or more metals in the list consisting of:—B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Ti, Zr, Hf and Rf, and
the M 2 type of metal is selected from one or more metals in the list consisting of:—P(5+), Nb(5+), As(5+), Sb(5+) and Ta(5+).
2. A method according to claim 1 , wherein the nitrided metal oxide consists of two to four metal cations, and oxygen and nitrogen anions.
3. A method according to claim 1 , wherein the nitrided metal oxide is selected from the list consisting of:—AlPON; ZrPON; SnPON; ZrNbON; GaSbON; and GaAlPON, either unsupported or supported on a support, the support comprising alumina, silica, silicon nitride, colloidal silica, titania or aluminium phosphate.
4. The method of claim 1 , wherein the nitrided metal oxide is supported on a support selected from the group consisting of: alumina, silica, silicon nitride, colloidal silica, titania or aluminium phosphate.
5. A method according to claim 1 , wherein the ethylenically unsaturated acid or ester produced by the process of the invention is selected from methacrylic acid, acrylic acid, methyl methacrylate, ethyl acrylate or butyl acrylate.
6. The method of claim 1 , wherein the step of contacting formaldehyde with a carboxylic acid or ester in the presence of a catalyst is also carried out in the presence of alcohol.
7. The method of claim 1 , wherein the ethylenically unsaturated carboxylic acid or ester is produced with a catalyst system by contacting formaldehyde or a source thereof with a carboxylic acid or ester of formula R 3 —CH 2 —COOR 4 wherein R 4 is either hydrogen or an alkyl group and R 3 is either hydrogen, an alkyl or an aryl group, in the presence of a catalyst of the catalyst system, wherein the catalyst comprises a nitrided metal oxide having at least two metal cations, M 1 and M 2 , wherein:
the M 1 type of metal is selected from one or more metals in the list consisting of:—B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Ti, Zr, Hf and Rf, and
the M 2 type of metal is selected from one or more metals in the list consisting of:—P(5+), Nb(5+), As (5+) Sb(5+) and Ta(5+) to produce the ethylenically unsaturated carboxylic acid or ester.
8. The method of claim 1 , wherein the ethylenically unsaturated carboxylic acid or ester is an α,β ethylenically unsaturated acid.