Catalyst composition for selective hydrogenation with improved characteristics

A heterogeneous shell catalyst for selective hydrogenation of unsaturated hydrocarbons, the heterogeneous shell catalyst comprising:

• (i) a porous solid substrate having an uncoated BET surface area of less than 9 m2/g and an integral pore volume of 0.007 to 0.04 ml/g;
• (ii) a metal or metal-alloy shell comprising palladium included on the substrate having a thickness of 100 μm to 500 μm;
• and
• (iii) 0.1% to 5% by weight of the heterogeneous shell catalyst of one or more ionic liquids deposited within a pore surface of the porous solid substrate having the integral pore volume in a quantity that is less than the integral pore volume to provide an ionic liquid shell that is between 10 μm thick and 2000 μm thick, wherein a total quantity of the one or more ionic liquids used is between 0.01% to 5% by weight of the heterogeneous shell catalyst,
• wherein the one or more ionic liquids consist of one or more compounds of the formula:
• [A]n+[Y]n−,
• wherein:
• n=1 or 2;
• [A]n+ comprises an imidazolium cation of the formula (III)
• wherein R, R1, and R2 are independently selected from the group consisting of hydrogen and linear or branched C1-C12-alkyl groups, or [A]n+ is selected from the group consisting of 1-butyl-1-methylpyrrolidinium, 1-ethyl-3-methylpyridinium, ethyldimethyl-(2-methoxyethyl)-ammonium, tributylmethylammonium, tricyclohexyltetradecylphosphonium, and mixtures thereof;
• and
• wherein [Y]n− is selected from the group consisting of bis(trifluoromethylsufonyl)imide, dicyanamide, ethylsulfate, methylphosphonate, methylsulfate, octylsulfate, tetracyanoborate, tetrafluoroborate, tricyanomethane, triflate, tris(pentafluoroethyl)trifluorophosphate, and mixtures thereof.