Talk:Catalysis

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Contents 1 Something other than chemistry? 2 Other uses 3 Alter rate/accelerate/inhibit 4 I do not understand the Generic Graph. 5 Merge of Catalyst to here 6 Image 7 Lead 8 Error ? 9 Berzelius 10 Popular Culture 11 Regernerating catalysts 12 History of catalysis 13 Introductory phrase 14 Suggested merge: Notable examples - Catalytic Processes

[edit] Something other than chemistry?

Please the graphic showing the two competing curves at high and low Gibbs energy values for the non-catalyzed and catalyzed pathways is wrong and should be removed or changed from the figure. It is just too simplified, does not show the presence of several steps in the catalytic process. —The preceding unsigned comment was added by 88.2.63.88 (talk) 10:00, August 23, 2007 (UTC)

The term "catalysis" can mean things outside the discipline of chemistry. It can refer to any force that encourages change while remaining separate from the changed entities. For example, I wanted to GAY* you can go for the see also option, or add content to Catalyst (disambiguation) where other meanings are already present. Beware that you might get shot down by the wikidictionary people though.....(they are ruthless) V8rik 22:21, 28 September 2005 (UTC)

• • I realize now I really want to disambiguate "Catalyst", not "Catalysis". Thanks for the link. I couldn't find it before because I wasn't spelling it correctly. (This from someone who can't spell "something" or "chemistry". Ooops...) But I'm a musician and an editor-wannabe. I'm not a linguist. I don't know that I'm really qualified to write the article from scratch -- irrespective of the wrath of Wikidictionarists. Anybody else wanna give it a try? If not, I might give it a shot and see who tromps on me. Joe 02:37, 29 September 2005 (UTC)

---

removed this statement:

A common misunderstanding is that catalysis "makes the reaction happen", and that the reaction would not otherwise proceed without the presence of the catalyst. In biologically- or industrially-useful timescales, this may be true in a limited sense; however, a catalyst cannot make a thermodynamically unfavorable reaction proceed. Rather, it can only speed up a reaction that is already thermodynamically favorable. Such a reaction in the absence of a catalyst would proceed, even without the catalyst, although perhaps too slowly to be observed or of use in a given context.

it is commonly observed that reactions without a catalyst will not take place at all.

removed this statement:

The mechanisms by which a catalyst speeds up a reaction are many, but they are all based on the reduction of the activation energy that is necessary to initiate the reaction. If you think of a reaction as a hill to be passed, the activation energy is the uphill part from the reactants' energy level to the energy level of the activated complex. The activated complex can then descend on either side of the reaction, either returning to the reactants or becoming products. In the hill example, catalysis functions as a tunnel, providing an easier way to the other side of the hill.

confusing because catalyst does not lower activation energy but offers alternative pathway, tunnel analogy not clear

moved parts to homogeneous catalysis and heterogeneous catalysis

emptied out the see also section, better to have all the keywords in context rather than out of context, not all see also's are relevant

62.163.60.97 19:19, 15 Jun 2005 (UTC)

[edit] Other uses

Catalysis is also the name of a regional marketing company based in Seattle, WA [1].

Catalysis is also a software engineering methodology [2] probably made popular by this book: [3]. I would love to see an article about this... perhaps comparing it to RUP (if the two can be compared?). If I become qualified to write it before anyone else decides to do so, I will. —Preceding unsigned comment added by 70.187.220.73 (talk • contribs)

Dear 70.187.220.73, You are fully qualified to create an article (I would suggest: 'catalysis (programming language)'). Clicking the link will open the edit window, where you can start typing. If you make an account, you will get some links regarding style, wiki-markup-language on your own talk-page. Welcome! --Dirk Beetstra ^{T C} 20:03, 10 July 2006 (UTC)

Dirk, Thanks for the advice. I've created an account, got "the book" on Catalysis, and plan on coming up to speed. --Ed

[edit] Alter rate/accelerate/inhibit

Dear reader/editor. When I entered Wikipedia this document contained a phrase 'the opposite of a catalyst is an inhibitor' (or something of the like), I did disagree with that, an inhibitor is a compound that slows down a catalyst, but that is not the opposite. Today someone changed the 'acceleration' into 'process of altering' .. again .. I do not agree .. Catalysts accelerate a reaction, I do not see how a catalyst can slow down a reaction (when compared to an uncatalysed reaction). The catalyst in that case would have to bind a substrate, but then all the other substrates would react with normal rate. Or the catalyst has to be stoichiometric, and hold the substrate, but then, it is not a catalyst, because it is altered, the moment it releases the substrate, the substrate would react .. please, comments. --Dirk Beetstra ^{T C} 20:05, 22 June 2006 (UTC)

[edit] I do not understand the Generic Graph.

What is the 'Energy' axis? Heat? Potential Energy? Total Energy in system? According to the Graph you start somewhere then the energy rises for a while (substances are heated up from the outside?). Then at the same time, when you reach the 'activation energy' (=energy needed for reaction to take place) the line of the catalysed and the uncatalysed reaction start to drop (the chemical reaction starts?) and they reach the same low point at the same time (according to legend this means they have the same result). Having the same result at the same time this seems to mean the overall speed was the same.

Maybe there is a very simple explanation for this Graph but I fail to see it. If someone would explain and/or alter the legend I would appreciate it.

Pukkie 14:28, 11 October 2006 (UTC)

An explanation is given in the article about catalyst. I have added a merge tag to the latter.   Andreas   ^(T) 14:35, 11 October 2006 (UTC)

The merger is a good idea. To be honest I do not see the explanation. I think I do understand the text in the catalyst and catalysis articles but I still fail to understand the graph. Maybe the solution is scale: is this supposed to give a graph for indidual molecules or for, say, kilojoules and minutes? If someone would give a clear example with units I probably won't be too stubborn to admit it was my mistake and this graph, as it is, is informative enough for most people. Pukkie 19:08, 11 October 2006 (UTC)

The "energy" in the graph is really the free energy. This is the thermodynamic energy of the system. The graph shows that you need to go over an energy barrier to get from the reactants to the products. The type of energy you add to get over this barrier can come in many forms, but heat is the most typical (light is not uncommon either). The x-axis is more complicated. Technically, this is the "reaction progress". At one point in the reaction progress, you have a reactant. At another point, you have the product. At points in between you have something between the product and the reactant. For a very simple reaction like 2 H· → H₂, you can think of the distance between the two H atoms as the reaction progress. For the reactants, they are very far apart. At the products, the distance is the same as a H-H bond length. In between the distance is somewhere in between. Isthmus Labrat 00:38, 14 October 2006 (UTC)

Your explanation makes sense to me, more than the generic graph anyway. I still have problems with a macro interpretation. Also: maybe the X-axis should be named: reaction progress. Pukkie 10:09, 16 October 2006 (UTC)

I disagree. The Gibbs free energy is a thermodynamic term that pertains to the average of a class of molecules/particles. The schematic graph shows the energy of a reaction complex along the axcis of "reaction progress", depicted as a smooth function. This can only pertain to a single reaction complex. In contrast, the activation energy as such is a thermodynamic concept, because the peak in the graph corresponds to a particular (instable) quantum state, and the Gibbs free energy or reaction complexes in that state can be defined. This concept is admitted very poorly treated in conventional textbooks.   Andreas   ^(T) 14:14, 16 October 2006 (UTC)

External links:

• http://www.chemguide.co.uk/physical/basicrates/catalyst.html

[edit] Merge of Catalyst to here

• Support. That article is a poor one and overlaps with this one. It can be improved by merging here. --Bduke 05:54, 30 October 2006 (UTC)
• Support They are redundant sometimes and sometimes one has info that's missing in the other one. Anyway merging is just the first step, much improvement is also needed in these articlesKnights who say ni 08:45, 30 October 2006 (UTC).
• Support These are tow articles about the same subject.   Andreas   ^(T) 13:01, 30 October 2006 (UTC)
• Support the merge for now. Though I do think the two are somewhat different, the two articles overlap too much for the moment. We might consider a split later when necessary. --Dirk Beetstra ^{T C} 13:53, 30 October 2006 (UTC)
• SupportI say that THIS article is a poor one and overlaps with the other.

[edit] Image

The image could be improved (as we did with the one in enzyme) so that it shows that reactants is the beginning and products is the end, and more importantly, that the varibale in X axis is not time, but reaction coordinate!!! Anyone with the ability/will to do it?? (I'd do it but i don't know anything about graphic programs) Knights who say ni 10:37, 27 November 2006 (UTC)

Please explain one example of a catalysts.

What makes a chemical reaction of two substances speed?

please send the answer to hide_and_go_away@rock.com

I agree with Knights who say ni, I don't really like the layout of the diagram either. I mostly don't like the way this reaction is going "up-hill" on the energy axis (i.e X --> Y). It sort of implies a catalyst can drive a reaction to an endothermic product as if by magic. Yes, you can make an argument that the reaction is just showing a reversible reaction and so the LHS vs RHS on the reaction coordinate axis doesn't mean much. However, it is still a tad misleading and doesn't need to be so. People can get confused about what a catalyst does, let's not fuel that fire. for example as mention above think the image on enzyme page (see below) is better laid-out overall.

Quantockgoblin (talk) 22:41, 26 March 2008 (UTC)

[edit] Lead

Could someone add a mention of a simple example of catalysis that the layman can understand? i.e. "A common example used to demonstrate an catalyst is...yada yada yada" Pdelongchamp 16:55, 29 June 2007 (UTC)

[edit] Error ?

This article names the chemist Alexander Mitscherlich: "Other early chemists involved in catalysis were Alexander Mitscherlich who in 1831 referred to contact processes" The problem is that he was born in 1836 so that does not add up. Can someone who understands this topic look into this? --TheDJ (talk • contribs) 20:17, 31 July 2007 (UTC)

[edit] Berzelius

I think Jöns Jakob Berzelius was the first one to use the term "catalysis", but he's not mentioned here. I attach the link for Berzelius in the enciclopaedia britannica: [4] --193.147.219.225 14:24, 26 October 2007 (UTC)

This article used to said that but someone vandalized it. I have fixed it. --Itub 15:45, 26 October 2007 (UTC)

[edit] Popular Culture

MySpace offers the option of a mood, "catalyzed," characterized by a smiley-face emoticon rotating clockwise, strongly implying that the user influenced by this mood had experienced chemical catalysis. Recommend a small marijuana leaf be affixed to the top right corner of the Popular Culture section I so hope you will include in this magnificent article. :) —Preceding unsigned comment added by 68.238.74.157 (talk) 01:20, 10 December 2007 (UTC)

[edit] Regernerating catalysts

Is it worth mentioning that many catalysed reactions, particulally organic reactions involving H+ regernerate the catalyst with a different proton? For examle a keto enol tautomerism is acid catalysed - the reclaimed H+ is not the same as the H+ from the acid. This can be proved using a deuterated acid. Noosentaal (talk) 15:14, 14 December 2007 (UTC)

[edit] History of catalysis

• John Meurig Thomas (1994). "Turning Points in Catalysis". Angewandte Chemie International Edition in English 33 (9): 913 - 937. doi:10.1002/anie.199409131. 
• [5]
• Bård Lindström and Lars J. Pettersson (2003). "A Brief History of Catalysis". CATTECH 7 (4): 130-138. doi:10.1023/A:1025001809516. 
• [6]
• Keith J. Laidler (1986). "The development of theories of catalysis". Archive for History of Exact Sciences 35 (4): 345-374. doi:10.1007/BF00357306. 
• Eduard Färber (1938). "A Philosophy of Catalysis". Isis 29 (2): 398-402. 

some literature which will be implemented into the history section soon!--Stone (talk) 10:11, 7 January 2008 (UTC)

[edit] Introductory phrase

I propose to alter the wording of this and await for objections/approval before I do it. Using double brackets=deletion, italics=insertion the following version is suggested:

In chemistry and biology, catalysis is ((the)) a way of accelerating((on)) the rate ((increase in rate)) of a chemical reaction by means of contacting the reactants with a substance called a catalyst, which ((is)) itself is not consumed by the overall reaction which often means the shifting the reaction equilibrium in one particular direction.. More generally, one may at times call anything that accelerates a process, a "catalyst" (From the Greek καταλύειν, meaning to annul or to untie or to pick up). LouisBB (talk) 20:41, 21 February 2008 (UTC)

Sorry, but the phrase which often means the shifting the reaction equilibrium in one particular direction. is not true. In fact a catalyst accelerates both forward and reverse reactions equally so that the position of equilibrium is unchanged, although the rate of approach to equilibrium is faster. Dirac66 (talk) 04:23, 22 February 2008 (UTC)

Many thanks Dirac66 for putting me right on this one. Does this apply to all catalytic action regardless of phase, order etc.? I am very pleased really, at least I have not touched the article without consulting everybody. Much better, than arguing on the article page. Thanks again LouisBB (talk) 18:58, 22 February 2008 (UTC)

There is one further idea, namely adding a short phrase on inhibitors to go at the end of the paragraph, as these are often referred to as negativ catalysts.LouisBB (talk) 19:06, 22 February 2008 (UTC)

The last sentence of the introduction already defines "inhibitor" and provides a link to an article with further details. The phrase "negative catalyst" could be explained also, although it was used more before catalytic mechanisms were understood. I would suggest adding (yes, at the end of the paragraph) a sentence such as "An old term for inhibitor is "negative catalyst", but this term is now best avoided since the mechanisms for catalysis and for inhibition are now known to be different." What do you think of this suggestion? Dirac66 (talk) 00:43, 23 February 2008 (UTC)

I have missed that one. Your suggestion sounds fine to me, but what I would also suggest is to append the last paragraph to the end of the first one, as it seems to me that it is part of the definition.

I have modified the last paragraph from catalyst to catalytic reaction (to be pedantic) LouisBB (talk) 05:06, 23 February 2008 (UTC)

On looking at my last suggestion (about transferring the last paragraph to the end of the first one) and on re-reading it I have some more observations/suggestions for improvement: 1) I would turn round the sentence of that last paragraph, so that the thought is identically put to the definition of the catalys, by putting the defined terms at the end of the phrases, 2) I reckon that the definition of inhibitor is incorrect: it does not reduce the action of a catalyst, but it slows down the chemical reaction itself (without a catalyst) and finally 3) if I am right promoter is sometimes written as promotor (Are there no such article titles in WP yet?) LouisBB (talk) 05:47, 23 February 2008 (UTC)

My comments: 1.Re place of last paragraph: promoters and inhibitors are only present in SOME case of catalysis, so they are subsidiary concepts which should not be at the very beginning. The end of the introduction is soon enough.

2. Re inhibitor: First, an inhibitor has no effect without a catalyst, which shows that its effect is indeed on the catalyst. From a macroscopic viewpoint one could say that its effect is to slow down the catalysed reaction, since less product is formed per unit time. However modern chemists prefer the molecular viewpoint which is that the inhibitor reacts with and inactivates some of the catalyst. The catalyst molecules which are not inactivated still cause reaction at the same rate, but there are less of them. See also the link for inhibitor

3. Re promoter: Promoter is the usual spelling. I agree that there should be an article on Catalyst promoter, but no one has written one yet. There is one article on promoter, but it deals with DNA promoters in molecular biology, which are not the same thing. Dirac66 (talk) 01:00, 24 February 2008 (UTC)

[edit] Suggested merge: Notable examples - Catalytic Processes

I think the two sections headed notable examples and catalytic processes should be merged, and if anything, the latter section removed completely. It you scroll down you get the impression that the authors gave up writing towards the end and decided to merely list things. What does everyone else think? --Cimex (talk) 12:11, 4 May 2008 (UTC)

Notable examples is clearly better written, as related examples are placed together with some explanatory comments. I would suggest a "slow merge" by transferring one example at a time from catalytic processes to the appropriate place in notable examples and adding brief comments. For example, the inorganic reactions (Haber, HNO₃, H₂SO₄) can be placed together. Dirac66 (talk) 16:33, 4 May 2008 (UTC)