| 摘要 |
<p>Hydrogen chloride and oxygen are passed over catalytic compositions comprising (a) one or more copper chlorides, (b) one or more chlorides of a rare earth metal or metals, the atomic ratio of rare earth metal or metals to copper being at least 0,1:1 and (c) one or more alkali metal chlorides, to produce chlorine. Rare earth metals are defined as the 15 elements having atomic numbers of from 57-71 plus scandium, ythrium, zirconium, thorium and uranium. Preferably component (b) comprises chlorides of didymium, i.e. lanthanium and usodymium with smaller quantities of praseodymium and samarium. Alternatively component (b) may comprise those rare earth metals the highest possible valency of which is lower than 4. The catalytic compositions may be supported on pumice, ceramic or silica gel having a surface area of at least 200 m.2/gm. and pore size of at least 60 . Lithium, sodium and potassium chlorides are specified alkali metal chlorides. Additionally the catalytic compositions may include silver, lead or tin compounds. Initially a pre catalyst may be formed of compounds which on reaction with hydrogen chloride and oxygen will provide the chlorides as called for in (a), (b) and (c) above. The catalyst may be used as a fluidized bed. Reaction between hydrogen chloride and oxygen may be effected at 330 DEG -400 DEG C.</p> |
