A heterogeneous catalyst comprising a support and gold, wherein: (i) said support comprises alumina, (ii) said catalyst comprises from 0.1 to 5 wt % of gold, (iii) at least 90 wt % of the gold is in the outer 60% of catalyst volume, and (iv) particles of the catalyst have an average diameter from 200 microns to 30 mm; wherein weight percentages are based on weight of the catalyst.