Process for removing polyunsaturated hydrocarbons from C4 hydrocarbon streams in the presence of mercaptans, disulfides and C5 hydrocarbons

A process for removing polyunsaturated hydrocarbons from an olefin-containing C4 hydrocarbon stream that, in addition to C4 hydrocarbons, also contains C5 hydrocarbons in a range between 0.01 and 5% by weight and mercaptans and/or disulfides in a range between 0.01 and 200 ppm by weight,

• wherein the process comprises a first step and a second step as follows:
• in the first step, at least some of the polyunsaturated hydrocarbons from the olefin-containing C4 hydrocarbon stream are hydrogenated and reacted with the mercaptans and/or disulfides from the olefin-containing C4 hydrocarbon stream in a first reaction zone in a presence of a molar ratio of hydrogen to polyunsaturated hydrocarbons between 0.01 and 0.8,
• wherein the first reaction zone comprises one or more reactors connected in parallel and/or in series,
• wherein the first step is carried out using a first catalyst comprising an alumina support material and a metal, where the metal comprises a combination of palladium and platinum having a palladium concentration of up to 2.0% by weight and a platinum concentration of up to 1.0% by weight,
• wherein the concentration of the palladium is at least a factor of 2 higher than that of platinum,
• wherein no carbon monoxide is added to the C4 hydrocarbon stream in the first step, and
• wherein not more than 80 mol % of the available polyunsaturated hydrocarbons from the C4 hydrocarbon stream are hydrogenated and reacted in the first step;
• and
• in the second step, remaining polyunsaturated hydrocarbons in the olefin-containing C4 hydrocarbon stream are selectively hydrogenated using a second catalyst in the presence of hydrogen and carbon monoxide in a second reaction zone, which comprises one or more reactors connected in parallel and/or in series;
• wherein the second catalyst contains only a single metal of the 10th group of the periodic table, wherein the single metal is palladium;
• and
• wherein at least one removal of high boilers takes place between the first step and the second step.