Hydrogenation of MA/PD
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In the carbon trihydrogenation reactor, MA/PD hydrogenation uses Pd as a catalyst. Since alkynes are less reactive than alkenes and have a higher activation energy, why isn’t propylene primarily added to propane during hydrogenation? How is selective hydrogenation of MA/PD achieved? Is the product of the reaction propylene or propane? (Pd does not poison the imaging Lindlar catalyst like that)
The original poster isn’t in the ethylene industry – why ask such a question? There is a lot of information available on such fundamental questions.
The reaction product is propylene; what is ultimately desired is to convert MA/PD into propylene rather than propane.
Pd has a stronger adsorption capacity for alkynes and dienes than for alkenes, allowing for the selective hydrogenation of alkynes to alkenes. For the specific mechanism, please refer to relevant literature
The goal is to convert MAPD into propylene, but there are certainly losses during this process, with some of it being converted into propane. This depends on the selectivity of the catalyst; the better the selectivity, the lower the loss of propylene
There is another reason: when the amount of MAPD reaches a certain level, there is a risk of explosion. Most of the propylene will be produced in the reaction, and of course a small amount of propane will also be formed. The determining factors mainly depend on the selectivity of the cat, as well as the reaction conditions, such as temperature, etc