Some catalyst
Great work.
You can probably list some recent catalyst people are working on.
transition metal catalysis / Discussion
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I think increasing interests is focusing on research about catalysis in the following aspect currently:
1) Catalysis in Nanotechnology, For example , novel method was introduced to prepare catalyst with some special structure, like egg-shell structure.In addition,catalysis in the preparation of carbon nanotubes.
2) Green chemistry in catalysis, Clean oxidation/halogenation processes using O2,H2O2(C2H4O, C3H6O, ECH)
Avoiding toxic chemicals in industry
Two main parameter to evaluate the catalysts is activity and catalytic efficiency . I think later work will emphasize a lot on the catalytic efficiency, from the environmental and engergy consideration.
Nice work Zengmin. Could you probably elaborate on some general principles of catalysis, such as the mechanism for example?
Thanks for your suggestion, it is really good. I will talk more about the general principle of catalysis.
Hi, Zengmin,
Nice job! Your information about the "Woodward-Hoffmann postulate", which dividing molecular transformations into “allowed” and “forbidden” categories, do drag a lot of attentions from me. It must be an very important tool to direct the catalyst development. Do you have the reference for the "Woodward-Hoffmann postulate"? I am interested very much in reading them. Thanks!
I am go glad that you are interested in the Woodward-Hoffmann rules. I had added more information about the Woodward-Hoffmann rules, I think this referece will be helpful for you,
Roald Hoffmann, Robert B. Woodward, "Conservation of orbital symmetry", Acc. Chem. Res., 1968, 1 (1), 17-22.
The followin website can give you more information about this pricipal:
http://en.wikipedia.org/wiki/Woodward-Hoffmann_rules
http://web.uconn.edu/~ch351vc/cgi-bin/woodh1.pl
http://falkorpdx.files.wordpress.com/2009/03/woodward-hoffmann-rules.pdf
And it must point out this rule has a certain limitation. So there are still some controversy about this rule.
Hi, Zengmin:
Nice job. Your page is ordered very well. Could you attach some information about how people find this interesting topic?
I am sorry, I am not quite get to your point. Do you mean, how people find catalysis in transition metal a topic or find a specific priciple, like Woodward-Hoffmann rules a topic?
As far as the transition metal catalysis is concerned, people have done a lot of work on it. The reason is 1) catalysts is widely used and so extensively investigated 2) transition metal is popular catalyst and it has some distinguised properties.
If you are talking about Woodward-Hoffmann rules , there is a very interesting story about the discovery of this rule. And some dispute coming from the noble prize for this rule. You can read this story "Whose idea was it?
Dispute over Nobel-winning theory shows how hard it is to trace origins of scientific discoveries"
http://www.boston.com/news/globe/health_science/articles/2005/03/01/whose_idea_was_it/
Dear Zengmin, you page is very nice! Since there are so many kinds of catalysts, how people determine which one to use in their reactions? Especially, when do people choose transition metals? Is there any principle of that?
That is a good question. I think to select a catalyst for a specific reaction need a lot of empirial and theoretical work. You need to take into consideration of the mechanism of the chemical reaction, and the structure and the nature of the catalysts. Take the hydrogenation of CO for the methanol synthesis as an example. Cu-Zn-Al was the conventional catalysts for this reaction. It has several advantages, 1) high activity 2) low cost 3) long life, Palladium could be a good hydrogenation catalyst, however, compared with copper based catalyst, it was so expensive for commercial use for this reaction. But for another reaction, like selective hydrogenation of ethyne to ethylene, palladium is widely used. Because in this reaction, we think the selectivity is far outweigh the other parameters, like the activity. palladium catalyst has a good selectivity, it could selective absorb ethyne to its surface. Especially, for this reaction , the reactant, I mean, in the industrial process, contains only a rather small amount of ethyne. So not too much catalysts are needed for this reaction, in other work, supported noble metals, catalysts containing Pd<1% is enough for this reaction.
To evaluate whether a catalyst is suitable for a reaction, you need to consider the catalysis activity, the selectivity, the life , the cost, So,it always takes many years of repeated experiments from invention of a novel catalyst, then laboratory test, then pilot plant test to prove it, until it finally could used in the industrial process.
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