Claims
- 1. A process to make formaldehyde from methane comprising partially oxidizing methane with a molecular oxygen containing gas over a catalyst comprising MoO.sub.3 on a silica support having a low sodium content of less than 350 ppm, said amount of MoO.sub.3 being at least a catalytically effective amount and up to an amount where the Mo content is about 50% by weight of the catalyst.
- 2. A process according to claim 1, wherein the support is a silica selected from the group consisting of silica obtained from the hydrolysis of silicon tetraalkoxides, fumed silica, acid washed silica gel, acid washed precipitated silica and mixtures thereof.
- 3. A process according to claim 1, wherein the silica support has a BET nitrogen surface area of at least 20 m.sup.2 /g.
- 4. A process according to claim 1, wherein the silica support has a sodium content of less than 100 ppm.
- 5. A process according to claim 4, wherein the silica support has a sodium content of less than 20 ppm.
- 6. A process according to claim 5, wherein the silica support has a sodium content of about 1 ppm or less.
- 7. A process according to claim 1, wherein the amount of MoO.sub.3, expressed as wt % Mo, is an amount up to 15 wt % Mo.
- 8. A process according to claim 7, wherein the amount of MoO.sub.3 is from about 0.5-15 wt % Mo.
- 9. A process according to claim 2, wherein the silica is a silica obtained from the hydrolysis of silicon tetraalkoxides and the sodium content is less than 4 ppm.
- 10. A process according to claim 9, wherein the sodium content is less than 2 ppm.
- 11. A process according to claim 1, wherein the silica support is an acid washed silica gel.
- 12. A process according to claim 1, wherein the silica support is an acid washed precipitated silica.
- 13. A process according to claim 1, wherein the temperature is up to 700.degree. C.
- 14. A process according to claim 13, wherein the temperature is between 500.degree. and 700.degree. C.
- 15. A process according to claim 1, wherein the space velocity is 1,000 to 20,000 hr.sup.-1 at normal temperature and pressure.
CROSS-REFERENCE TO RELATED APPLICATION
Application Ser. No. 723,681 filed Apr. 16, 1985, describes and claims another catalyst which can be used in the present process invention.
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