PROCESS FOR PREPARING HYDROXYLAMMONIUM SALTS

摘要

1. Process for preparing a hydroxylammonium salt through catalytic reduction of nitrate ions with hydrogen in an acid medium in the presence of a palladium and/or platinum catalyst on a carrier, characterised in that the catalyst includes halogen ions at a level of at least 0.00025 and at most 0.004 mmol halogen ions per m<2> of palladium and/or platinum surface area. 2. Process according to claim 1, characterised in that the halogen ions are present at a level of between 0.001 and 0.002 mmol halogen ions per m<2> of palladium and/or platinum surface area. 3. Process according to any one of claims 1-2, characterised in that the halogen ions are introduced into the catalyst prior to introduction of the catalyst into the reactor. 4. Process according to any one of claims 1-3, characterised in that the halogen ions are iodine and/or bromine ions. 5. Process according to any one of claims 1-4, characterised in that the catalyst is on a carrier material of activated carbon or graphite. 6. Process according to any one of claims 1-5, characterised in that the catalyst is treated with a halogen compound selected from the group consisting of I2, Br2, Cl2, F2, HI, HBr; alkali(ne earth) salts of iodine, bromine, chlorine and/or fluorine, iodinated, brominated, chlorinated and/or fluorinated aliphatic, aromatic, branched or linear hydrocarbons having 1-12 C atoms or mixtures thereof. 7. Process according to claim 6, characterised in that the halogen compound is an iodine- and/or bromine-containing compound. 8. Process according to any one of claims 1-7, characterised in that the catalyst is activated by the presence of one or more compounds of the elements from the group comprising Cu, Ag, Au, Cd, Ga, In, T1, Ge, Sn, Pb, As, Sb and Bi.