Process for the production of hydrogen cyanide by the BMA process and catalyst for the implementation therefor
View Patent ↗The invention relates to an improvement to the BMA process for the production of hydrogen cyanide from methane and ammonia in the presence of a platinum-containing catalyst. The problem of sooting, and thus the decrease in activity, of the catalysts can be reduced, or the activity increased, in that the catalyst is doped with an element from the series Cu, Ag, Au, Pd and W. The doping is preferably in the range of 0.01 to 20 mole % doping element, based on Pt.
1. A process for the production of hydrogen cyanide by the BMA process, wherein an aliphatic hydrocarbon with from 1 to 4 carbon atoms is reacted with ammonia in the presence of a platinum-containing catalyst at 1000° C. to 1350° C. and hydrogen cyanide is separated from the reaction gas formed and wherein the platinum of the catalyst is doped with at least one element selected from the group consisting of copper, silver, gold, and tungsten, the quantity of copper when present being not more than 30 mole %, based on platinum.
2. The process of claim 1 , wherein said platinum is doped with 0.01 to 50 mole % of an element selected from the group consisting of silver, gold and tungsten.
3. The process of claim 1 , wherein said catalyst additionally comprises aluminum or magnesium in elemental or nitride form.
4. The process of claim 3 , wherein said catalyst comprises aluminum oxide.
5. The process of claim 1 , wherein said catalyst comprises a support material consisting of an oxide or nitride ceramic material.
6. The process of claim 5 , wherein said support material is aluminum oxide.
7. The process of claim 1 , wherein said catalyst comprises a coating on a shaped article consisting essentially of aluminum oxide, said coating being fixed on said shaped article by an oxide or silicate adhesive, wherein said coating comprises as its main components: platinum, doped with gold and/or silver; and aluminum in the form of aluminum nitride and/or a platinum-aluminum alloy.
8. The process of claim 7 , wherein said shaped article is a reaction tube and said coating is fixed on the inside of said reaction tube.
9. The process of claim 1 , wherein said catalyst is prepared by the steps comprising:
a) applying a suspension comprising particulate elemental platinum; particulate aluminum or aluminum nitride; at least one particulate doping agent selected from the group consisting of copper, silver, gold, tungsten, palladium and compounds of these elements; a precursor of an oxide or silicate adhesive; and a carrier liquid onto a shaped article consisting essentially of aluminum oxide,
b) evaporating the carrier liquid and
c) heating the shaped article coated in this way to a temperature of from 1000° C. to 1350° C.
and wherein the atomic ratio of Pt to Al is from 0.01 to 10 and the molar ratio of Pt to doping elements is at least 1:0.001.