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Topic: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?  (Read 18942 times)

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Offline Corribus

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #30 on: August 21, 2013, 11:37:08 AM »
I understand your point of view. On the other hand, whether or not a new route qualifies as "greener" kind of depends on the definition of "green".  What is green? To my mind it's another one of those words like "natural" that feels good but doesn't really mean anything at all. Is a green reaction one that doesn't use as much energy? Or is it a reaction that doesn't use an organic solvent? If a reaction uses more energy, but you're driving the reaction using hydroelectric power, is that more green than using a more efficient route but running your heating mantle from a gas-powered generator?

I knew a guy who had an electric car and he'd go around bragging about how environmentally friendly it was and how he could get like 60 mpg or whatever, and he would look down his nose at all of us who drove gas guzzlers, as though he were somehow superior. I once pointed out to him that he had to plug in his car somewhere in order to charge it, and he said of course, and I said, well where do you think the power comes from in your house? Turns out his house was powered by coal.  Oops.  So was the expensive electric car he was driving really "green"?  Didn't stop him from continuing to tell us all wonderful he was being to the environment.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline curiouscat

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #31 on: August 21, 2013, 12:09:09 PM »
I understand your point of view. On the other hand, whether or not a new route qualifies as "greener" kind of depends on the definition of "green".  What is green? To my mind it's another one of those words like "natural" that feels good but doesn't really mean anything at all. Is a green reaction one that doesn't use as much energy? Or is it a reaction that doesn't use an organic solvent? If a reaction uses more energy, but you're driving the reaction using hydroelectric power, is that more green than using a more efficient route but running your heating mantle from a gas-powered generator?


Fair enough. That sounds like a general argument that "green chemistry" is itself ill defined. I've heard that view before and it has something to it too.

I just don't think that the papers route, as argued, was "better" to any reasonable person from the field. But that's just me. Which is part of the reason I posted. To see if it was indeed "just me". :)

Offline DrCMS

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #32 on: August 21, 2013, 02:01:53 PM »
You may have guessed this already but I do not think it's just you.

Offline Corribus

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #33 on: August 21, 2013, 02:03:47 PM »
Yeah my issue isn't whether it's a "better" or "worse" procedure - although such comparisons require a defined metric to have any value - but rather whether it should be considered "greener" or "not greener". To me it doesn't make much sense to criticize the procedure for being not very green, when "green" doesn't have a precise definition. Is it therefore any wonder articles like this might be accepted in a journal called "Green Chemistry"? If the editors, reviewers, authors, and readers all have a different idea of what Green means, is it really fair to criticize one party here for not conforming to the definitions of another? The criticism should be leveled against the overuse of an imprecise term, the function of which is primarily - in the minds of most people - a marketing gimic.

But is it really? Is there an objective, scientific definition of the term?  Consider this.

Here is EPA's definition of Green Chemistry: Green Chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances  (http://www2.epa.gov/green-chemistry)

Here is the definition from the Green Chemistry journal's "about" page: Green chemistry is the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products

Here is the ACS Definition: Green chemistry is the design, development, and implementation of chemical products and processes to reduce or eliminate the use and generation of substances hazardous to human health and the environment.  http://www.acs.org/content/acs/en/greenchemistry/about/green-chemistry-at-a-glance.html (Also has an interesting bit about the history of the term.)

You see that neither one of these definitions mention energy usage at all - the focus is on hazarous substances, not on any principle of using less or "cleaner" energy. Therefore I would argue that a procedure that uses water as opposed to organic solvent, even if it requires more energy, could be justified as meeting the journal's (and EPA's) definition of "Green".  On the other hand, I would also argue that the layman, and indeed many scientists (including myself), would probably tend to define "Green", at least in a casual way, on the basis of energy wastefulness, and hence I can see why the original article you cited could be judged to be "not Green at all". 

My opinion is that if you're going to judge the merits of a work against nebulous criteria that can have different definitions depending on whom you ask, you're just begging for a disagreement from someone.  I note that Green Chemistry has a reasonably high impact factor - almost 7 - which is probably explained by the fact that "environmental awareness" is politically friendly. There's a lot of money in the Green business.  I bet the editors get a lot of conflicting opinions from peer reviewers about what should be published and what shouldn't, and I'm sure lots of articles are published there which attract the enmity of people who don't think the material contained within qualifies as "green", at least according to their narrow definitions.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline curiouscat

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #34 on: August 21, 2013, 02:32:09 PM »
You may have guessed this already but I do not think it's just you.

Maybe we have a minority of two here. :) Maybe @disco too.

Offline discodermolide

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Re: Large Excess of Reagent: Why? Does this make sense to Organic Chemists?
« Reply #35 on: August 21, 2013, 08:00:35 PM »
Maybe Green Chemistry is all about trying to make your reaction mixture go green?
Adding vast amounts of chlorine or better using Nickel or Copper catalysts in large excesses? Cant think of anything else at the moment.
There is no such thing as green chemistry.
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