Process for producing sodium and zinc pyrithione

摘要

Disclosed is a process for producing a zinc pyrithione product having an acceptable white or off-white color and containing substantially no undesired 2-hydroxypyridine-N-oxide or metal salt complexes thereof, byPP(1) making sodium pyrithione by reacting a 2- halopyridine-N-oxide with sodium hydrosulfide and sodium carbonate (or a mixture of sodium carbonate and sodium hydroxide) under selected addition temperatures and reaction temperatures and in selected mole ratios; followed byPP(2) making zinc pyrithione by reacting the sodium pyrithione with a zinc salt.