Abstract BACKGROUND Pd nanoparticles over different supports were evaluated during the alkyne selective hydrogenation of medium chain (C 7 and C 5 ) and the 1‐pentene purification at mild operational conditions (150 kPa and 303 K). The role of support and chloride was investigated; γ‐Al 2 O 3 , γ‐Al 2 O 3 modified with Mg, CaCO 3 and activated carbon were used as supports, and PdCl 2 as precursor salt. The classical Lindlar catalyst was used as reference. RESULTS Surface acidity of supports, active sites dispersion and surface species (MgO, Pd x Cl y O z and/or functional groups) can favor or disfavor the desorption of 1‐alkene during the purification of 1‐pentene stream. The smallest particle sizes (3.8–10.0 nm) favor the dissociative adsorption of hydrogen over Pd° active sites, promoting good catalytic behavior. The best synthesized catalysts are Pd/Al–Mg and Pd/Ca, and their high selectivity (≥90%) is favored by the presence of superficial acidic Lewis sites. On the contrary, lower selectivity (74–80%) is assessed on catalysts with Brönsted acidic sites (Pd/Al and Pd/RX3) that favored the undesired overhydrogenation or isomerization reactions. CONCLUSION The geometric and electronic properties of the support have a major influence on the activity and selectivity of the catalysts. Low loaded Pd catalysts supported on Al 2 O 3 ‐Mg and CaCO 3 (Pd/Al‐Mg, Pd/Ca) can be used for the purification of medium or large terminal alkenes at mild reaction conditions as an alternative to the toxic Lindlar commercial catalyst. © 2021 Society of Chemical Industry (SCI).