A first stream containing 1,3-butadiene, C.sub.4 acetylenes, and optionally C.sub.3 hydrocarbons, is mixed with a portion of the liquid recycle stream from a C.sub.4 acetylene hydrogenation reactor containing hydrogenated C.sub.4 acetylenes and a molecular hydrogen-containing stream, the resulting mixed stream is then fed to a C.sub.4 acetylene hydrogenation reactor to selectively hydrogenate the C.sub.4 acetylenes in the crude butadiene stream without appreciable 1,3-butadiene conversion.

A first stream containing 1,3-butadiene, C.sub.4 acetylenes, and optionally C.sub.3 hydrocarbons, is mixed with a portion of the liquid recycle stream from a C.sub.4 acetylene hydrogenation reactor containing hydrogenated C.sub.4 acetylenes and a molecular hydrogen-containing stream, the resulting mixed stream is then fed to a C.sub.4 acetylene hydrogenation reactor to selectively hydrogenate the C.sub.4 acetylenes in the crude butadiene stream without appreciable 1,3-butadiene conversion.

Disclosed is a process for converting methane into value-added compounds. In this process, a gas mixture containing hydrogen as well as high-concentration acetylene formed through methane pyrolysis (e.g. non-oxidative coupling of methane) is selectively hydrogenated in the presence of a bimetallic supported catalyst. This process obtains ethylene from acetylene in the gas mixture while unreacted methane and hydrogen are recovered as byproducts and/or additionally recycled.

Disclosed is a process for converting methane into value-added compounds. In this process, a gas mixture containing hydrogen as well as high-concentration acetylene formed through methane pyrolysis (e.g. non-oxidative coupling of methane) is selectively hydrogenated in the presence of a bimetallic supported catalyst. This process obtains ethylene from acetylene in the gas mixture while unreacted methane and hydrogen are recovered as byproducts and/or additionally recycled.

The present disclosure relates to methods for selectively hydrogenating acetylene, to methods for starting up a selective hydrogenation reactor, and to hydrogenation catalysts useful in such methods. In one aspect, the disclosure provides a method for selectively hydrogenating acetylene, the method comprising contacting a catalyst composition with a process gas. The catalyst composition comprises a porous support, palladium, and one or more ionic liquids. The process gas includes ethylene, present in the process gas in an amount of at least 20 mol. %; and acetylene, present in the process gas in an amount of at least 1 ppm. At least 90% of the acetylene present in the process gas is hydrogenated, and the selective hydrogenation is conducted without thermal runaway. Notably, the process gas is contacted with the catalyst at a gas hourly space velocity (GHSV) based on total catalyst volume in one bed or multiple beds of at least 7,100 h.sup.−1.

The present disclosure relates to methods for selectively hydrogenating acetylene, to methods for starting up a selective hydrogenation reactor, and to hydrogenation catalysts useful in such methods. In one aspect, the disclosure provides a method for selectively hydrogenating acetylene, the method comprising contacting a catalyst composition with a process gas. The catalyst composition comprises a porous support, palladium, and one or more ionic liquids. The process gas includes ethylene, present in the process gas in an amount of at least 20 mol. %; and acetylene, present in the process gas in an amount of at least 1 ppm. At least 90% of the acetylene present in the process gas is hydrogenated, and the selective hydrogenation is conducted without thermal runaway. Notably, the process gas is contacted with the catalyst at a gas hourly space velocity (GHSV) based on total catalyst volume in one bed or multiple beds of at least 7,100 h.sup.−1.

A propane dehydrogenation and propylene purification process in which a stream comprising propylene, propane, and methyl acetylene and propadiene (MAPD) is mixed with a hydrogen stream then reacted in at least three distinct reaction zones in a hydrogenation reactor system where MAPD is hydrogenated by a high-selectivity hydrogenation catalyst in a first reaction zone, and a second and a third reaction zones each have a low-selectivity hydrogenation catalyst to remove unreacted hydrogen. The outlet stream leaving the hydrogenation reactor system is MAPD-free and can be fed to a splitter column, which now mainly serves to separate propylene from propane. Various embodiments of reaction zone arrangements in a single or multiple reactors are also provided.

A propane dehydrogenation and propylene purification process in which a stream comprising propylene, propane, and methyl acetylene and propadiene (MAPD) is mixed with a hydrogen stream then reacted in at least three distinct reaction zones in a hydrogenation reactor system where MAPD is hydrogenated by a high-selectivity hydrogenation catalyst in a first reaction zone, and a second and a third reaction zones each have a low-selectivity hydrogenation catalyst to remove unreacted hydrogen. The outlet stream leaving the hydrogenation reactor system is MAPD-free and can be fed to a splitter column, which now mainly serves to separate propylene from propane. Various embodiments of reaction zone arrangements in a single or multiple reactors are also provided.

Methods for the selective hydrogenation of acetylenic compounds in a product stream that includes isoprene. A method of selectively hydrogenating an acetylenic hydrocarbon in the presence of isoprene may include obtaining a hydrocarbon mixture comprising an acetylenic hydrocarbon, isoprene, and butadiene or cyclopentadiene, or both. If cyclopentadiene is present, the hydrocarbon mixture may comprise greater than 2 wt. % cyclopentadiene. The method may further include contacting the hydrocarbon mixture and hydrogen (H.sub.2) with a hydrogenation catalyst under reaction conditions that are more selective to the hydrogenation of the acetylenic hydrocarbon than the isoprene.

Methods for the selective hydrogenation of acetylenic compounds in a product stream that includes isoprene. A method of selectively hydrogenating an acetylenic hydrocarbon in the presence of isoprene may include obtaining a hydrocarbon mixture comprising an acetylenic hydrocarbon, isoprene, and butadiene or cyclopentadiene, or both. If cyclopentadiene is present, the hydrocarbon mixture may comprise greater than 2 wt. % cyclopentadiene. The method may further include contacting the hydrocarbon mixture and hydrogen (H.sub.2) with a hydrogenation catalyst under reaction conditions that are more selective to the hydrogenation of the acetylenic hydrocarbon than the isoprene.