Process for the environmentally appropriate degradation of chemical compounds which have one or more heteroatoms X, with X being F, Cl, Br, I, N, O or S, by cleavage of the C--X carbon-heteroatom bonds, characterized in that the chemical compounds or articles which contain the chemical compounds are treated with water vapor in the presence of an aluminum catalyst at 300.degree.-600.degree. C.
A method is provided for decomposition of chlorofluorocarbon to be decomposed and then disposed of. The process includes the following the steps of. A mixture of liquid chlorofluorocarbon substances to be decomposed (and then disposed of) and a liquid member are heated to a temperature of from about 500.degree. C. to about 700.degree. C. in order to produce a superheated vapor. The liquids member may be water, methanol, hydrogen peroxide, or mixtures thereof. The superheated vapor is maintained in a reactor for a sufficient reacting time in order to achieve decomposition of the chlorofluorocarbon in the mixture before passing through the reactor to a discharge outlet open to the environment.
A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200.degree.-800.degree. C., to convert the fluorine of the fluorine compound to hydrogen fluoride.
The present invention relates to a catalytic process for the destruction of PFC's and HFC's using a catalyst which comprises aluminum oxide that has preferably been stabilized through the addition of a stabilizing agent (such as, titanium, zirconium, or cobalt, or mixtures of these elements). The addition of these elements to the aluminum oxide unexpectedly enhances the catalyst's stability without significantly altering its reactivity. The total amount of stabilizing agent added to the catalyst can be as low as 0.005 parts (by weight) stabilizing agent per part (by weight) aluminum oxide (Al.sub.2 O.sub.3) or as great as 2 or more parts (by weight) stabilizing agent per part (by weight) aluminum oxide; so long as there is sufficient aluminum oxide available to effectively catalyze the destruction of the target PFC's and/or HFC's. An oxidizing agent, such as, for example, platinum, palladium, rhodium, iridium, silver, nickel, copper, iron, vanadium, and/or cerium, may be added to the catalyst to effectively convert any carbon monoxide to carbon dioxide.
A gas stream containing at least one fluorine compound selected from the group consisting of compounds of carbon and fluorine, compounds of carbon, hydrogen and fluorine, compounds of sulfur and fluorine, compounds of nitrogen and fluorine and compounds of carbon, hydrogen, oxygen and fluorine is contacted with a catalyst comprising at least one of alumina, titania, zirconia and silica, preferably a catalyst comprising alumina and at least one of nickel oxide, zinc oxide and titania in the presence of steam, thereby hydrolyzing the fluorine compound at a relatively low temperature, e.g. 200.degree. 800.degree. C., to convert the fluorine of the fluorine compound to hydrogen fluoride.
