【Q&A Question 035】2017.02.04
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This post was last edited by 955559 on 2017-7-21 21:44. [Q&A Question No. 035] 2017.02.04: What are the basic characteristics of catalysts? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) The basic characteristic of a catalyst’s action is that it alters the reaction pathway, changes the reaction activation energy, and modifies the reaction rate constant, but it does not affect the chemical equilibrium of the reaction. Petrochemical Area—“Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html The New Normal Cup—voting for the top 10 members of HaiChuan in 2016 is now underway; vote for the member you care about the most (please cast your valuable vote for the members in the Petrochemical Area). http://bbs.hcbbs.com/thread-1667649-1-1.html Summary post of Q&A questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657793-1-1.html Summary post of daily questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657794-1-1.html Summary post of Q&A questions from 2016 (updates completed). http://bbs.hcbbs.com/thread-1597792-1-1.html Third-phase selection of outstanding management members at HaiChuan. http://bbs.hcbbs.com/thread-1655902-1-1.html Petrochemical Area—“Creative Ideas for Energy Saving” event: http://bbs.hcbbs.com/thread-1666758-1-1.html Xiaomi phones are up for grabs. Summary post collecting chemical engineering-related materials from the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes are waiting for you (Source: HaiChuan Chemical Forum)
A catalyst is a substance that can participate in a reaction and accelerate or slow down the rate of that chemical reaction, without its own properties or quantity changing before or after the reaction. The basic characteristic of a catalyst is that it alters the reaction pathway, changes the activation energy of the reaction, and modifies the reaction rate constant, but it does not affect the chemical equilibrium of the reaction.
①A catalyst is involved in chemical reactions, but at the end of the reaction, its chemical properties and quantity remain unchanged; ② A catalyst can only shorten the time required to reach chemical equilibrium (that is, it acts as an accelerator), but it cannot change the equilibrium itself; ③ Catalysts exhibit significant selectivity – a specific catalyst can only catalyze specific chemical reactions
It can alter the rate of chemical reactions, but its own chemical properties remain unchanged before and after the reaction
It changes the reaction pathway, the reaction activation energy, and the reaction rate constant, but does not alter the chemical equilibrium of the reaction.
⑴A catalyst can only accelerate reactions that are thermodynamically feasible, not those that are not; (2) a catalyst can only speed up the approach of a reaction to equilibrium, but it cannot change the position of equilibrium (the equilibrium constant), and it can accelerate both the forward and reverse reactions simultaneously; (3) catalysts exhibit selectivity with regard to reactions – when there are multiple possible pathways leading to different products, the catalyst accelerates only one of them. ⑷The duration during which the catalyst remains in operation before it needs to be replaced (service life).
Selectivity, stability, activity, and a certain degree of mechanical strength!
It can alter the rate of chemical reactions, but its own mass and chemical properties remain unchanged
High catalytic activity, high mechanical strength; the catalyst is involved in the reaction, but at the end of the reaction, the catalyst itself does not undergo any changes in chemical properties or quantity. A catalyst can only shorten the time it takes to reach chemical equilibrium, but it cannot change the equilibrium itself. Catalysts exhibit significant selectivity; a specific catalyst can only catalyze specific reactions.