Hi everyone, I just confuse about some metals which are used as a catalysts for some organic reactions. How can we select the proper catalyst for each reaction? is there any book that can help me to understand the type and characteristics of those catalysts?? (I really confuse with those metal catalyst).
Hi Victor,
Organic Chemistry by Clayden, Greeves, Warren and Wothers is an excellent organic chemistry book, its like my bible!
It explains EVERYTHING very well and I haven't come accross anything that I don't understand in it yet.
Example is like this:
During catalitic hydrogenation process, my book write that we should use Ni catalyst. Why? how about other metal like Cu, Pd, and others?
There are 4 pages in the book above dedicated to catalytic hydrogenation, and explains what catalysts to use for what hydrogenation and explains why. Palladium is an excellent catalyst for hydrogenation (generally speaking), but of course platinum (oxide which is reduced to Pt during hydrogenation), rhodium, ruthenium and (Raney) nickel are all suitable catalysts in different situations, and pressure and heat is also needed for some hydrogenations. This is all very well explained in the book, I really recommend you get it, it was the best £35 I've ever spent.
Or like this, during Friedel-Crafts alkylation on benzene, we should use Al metal to act as catalyst while other reaction like bromination on benzene suggest that we should use Fe metal as a catalyst...why?
In these reactions a halogen-carrier (Lewis acid) is used, such as those you mentioned above as well as FeBr
3, and pyridine is also a very good catalyst for bromination. For Friedel-Crafts alkylations, AlCl
3 is normally the catalyst of choice. I'm not sure why this is the case for alkylation, but most lewis acids like these whould work fine; bromination is not very fussy, you can use any of the catalysts above.
To work out which catalyst is best, it is helpful to know the reactive intermediate that makes the reaction happen, then you can see if there are any compounds which help the formation of the reactive intermediate. Hope this helps
.