Process for isomerizing 1-butene to 2-butene

In a process for isomerizing 1-butene, wherein a hydrocarbon charge containing 1-butene and hydrogen is contacted with a Group VIII noble metal catalyst, at an isomerization temperature, the improvment wherein the catalyst results from the previous steps of:

• (a) passing a gas or a liquid providing a sulfur compound at a concentration of at least 0.1% sulfur b.w. through a bed of catalyst consisting essentially of a Group VIII noble metal at a temperature of 20.degree.-400.degree. C. for a sufficient time to pass therethrough at least 1 gram-atom sulfur per gram-atom of Group VIII noble metal, and then continuing said passing until substantially no more sulfur compound is retained by the catalyst,
• (b) contacting the catalyst with substantially sulfur-free hydrogen at a temperature of at least 50.degree. C., thereby obtaining a catalyst of both high activity and selectivity.