An improved method of preparing an ion exchange resin catalyst by partial neutralization of the ion exchange resin catalyst with a promoter. The promoter and a fluid are introduced into a vessel or a reactor which is partially filled with the ion exchange resin catalyst forming an ion exchange resin catalyst bed in the vessel or reactor. The fluid and the promoter are recirculated in an upflow direction at a velocity sufficient to partially fluidize the ion exchange resin catalyst bed and to achieve a rapid uniform distribution of the promoter throughout the catalyst bed.