[Corribus]

I guess we're unlikely to come to agreement on this issue, so there's no point in discussing further. However I will say I  think the tax argument is frankly rather a stretch. Even if I were to agree that the tax dollars spent on academic research are 100% wasted (and I could probably readily supply a dozen reasons why they're not), it's but a drop in the bucket compared to the amount of tax dollars that are wasted everywhere, higher education includced. Given the many peripheral benefits to academic research that have nothing to do with the direct research outcomes, I consider it a small (relative) financial loss. Yes, academia is a mess, but I consider this an insignificant part of the problem. Getting one's panties in a bunch because tax dollars are being wasted on research studies that don't move science forward in earth-shattering increments is a little like fretting over a stain on the couch while the house is burning down.

[curiouscat]

Sorry if I started WW-III.

Guys, I didn't intend this as a Chemist vs Engineers or Academics vs. Industry fight.

Just clarifying. But it's an interesting discussion, especially about what deserves and doesn't deserve to be published. My personal views are somewhere in between those of @corribus and @drCMS

@corribus: My only problem with your "lets publish generously" is a very practical, selfish one: I find I've to wade through piles of crap before I find a good paper worth emulating.

Of course, one man's crap could well be another's steak. Ah well.

[DrCMS]

@ Corribus  I certainly do not think all academic research is a waste of money but some is.  I think it's more than you do but we both think some money is wasted.  Just because other areas of government spending waste much much more does not mean the scientific community can not put its own house in order.   I do think there should me more focus on practical applications & improvements from academia.  I dread getting enquiries from academics because so far in 12 years in my current job not a single enquiry from academia has led anywhere but round in circles before disappearing in a puff of hot air.  I end up wasting time getting to the details to find out it's not going to work because the people who have been doing the work do not have a clue how to design a process that can be scaled up.

@ curiouscat  I'm against the publish anything approach for the same reason as you plus the fact that it devalues the importance of good publications and validates the waste of time and effort that went into the work.

[orgopete]

Me, I mentally determined 800/2 = 400:1, but I'm still trying to figure out how (460,000/18 mg/mmol)/74.6 mmol equal 210:1.

Since I'm not an academic, but a low level know nothing industrial, I really can't judge academic work, but aren't there agencies who do? Again, I'm still pretty sanguine about all of this. Academic vs industrial, like one is better than another? You should check my patents (which I did not fund). Fortunately for me, we charged the taxpayers voluntarily, you know, like the MS Zune, the Apple Newton, etc. Now that I think about it, what does this forum tell you about anyone who posts here (and I include myself)?

Back to the post, I don't know whether the green chemistry paper had great merit or not. I did not read it. My comment was about being careful when simply looking at molar ratios. I knew phthaldehyde would have limited water solubility, but water has a high molar concentration and is cheap. So I didn't know if I should have been shocked by the molar ratios without comparing it to other reactions.

[Corribus]

@curiouscat

World War 3? This? You haven't been around the internet much, have you? Hell, seeing as Hitler or the nazis haven't been brought up yet, this isn't even a proper argument yet.

@DrCMS

I would strongly agree that the lack of support for (actually, stigma against) applied research in academia is something that needs to be addressed. Although, I'd put a lot of the blame on funding agencies like NIH and NSF rather than acadmic scientists, who only do what is needed to secure funding. About the only group it seems any more that funds applied research outside of industry is the military, and they usually do all that stuff in house.

In short, I guess I'll only say that while here you have faulted scientists, I think blame goes to the system in which said scientists are trying to thrive. Of course, it might be argued that it was the scientists who created this system in the first place, but nevertheless, I regard the process of scientific inquiry to be at least as valuable as its products. Even if you end up nowhere, in other words, you've still learned something, and there's always the chance that an idea that seems to have no merit or chance of success will be the next revolutionary breakthrough. I therefore regard the expenditure of tax dollars toward all kinds of basic research to be well worth the risk, particularly since it's such a small slice of the overall pie, and media reports about wasteful research spending, like the infamous "shrimp treadmill", I regard as being destructive because they ignore the larger context of scientific research and prey upon the ignorance of the average layman. The fact is that many great discoveries have come, serendipitously, out of research in areas that most people thought useless or even heretical. 

[DrCMS]

@ orgopete If you use the molecular weight of ethanol rather than water you might get the answer I did.  My big problem with the "green" claim is the huge amount of energy need to heat that much water up to 250°C and cool it down again.

@Corribus yes the funding bodies do have a lot to do with the issue.  I also think universities do not train students with the right skills for jobs outside academia.

[orgopete]

@ orgopete If you use the molecular weight of ethanol rather than water you might get the answer I did. 

Oops, I missed the solvent change. Okay, let's get back to the point of the original post, "Large Excess of Reagent…". This was what I was attempting to reply about, even though this may seem to be a large molar ratio, water has a high molar concentration. If we compare the concentration, it was 1.86% in water. Even though I erred in calculating from water than ethanol, the concentration was 2.17% in ethanol. I would still argue this is not greatly different.

[DrCMS]

@orgopete yes the volumes of water and ethanol are only about 30% different but and this is a big but the water reaction is at 250°C while the ethanol one is done at room temperature and that will make a huge difference to the energy cost of each reaction.  If you do not think about the relative energy efficiency of different processing how can you say one is more green than another?

[orgopete]

@DrCMS

I found this paper's abstract intriguing, almost ridiculous but was wondering what others think:

"Phthalaldehyde and 1,4-cyclohexanedione react in the 2:1 molar ratio via a crossed aldol condensation in sub- and supercritical water to produce 6,13-pentacenequinone. The reaction conditions were optimized at 77% yield at 250 °C for 60 min with the starting molar ratio of 2:1:800 for phthalaldehyde, 1,4-cyclohexanedione and water, respectively."

Why would anyone try a reaction in a 800x solvent excess. Does this make sense, as a chemist? As an engineer I find it hard to believe this can ever be workable commercially, just due to the large excess of water.

Looking that the authors published in the journal "Green Chemistry" I'd assume they imply some utility to this scheme, not merely the science of it?

http://pubs.rsc.org/en/Content/ArticleLanding/2009/GC/b914784p

Have others have had a chance to carry out a reaction with a 800x excess of solvent ever? (Even adjusting for the molar -> mass fractions that's still like working at 0.5% concentrations)

If you read my comments, I don't believe I had extolled the virtues of "green chemistry", especially of a paper I had not read. Again, you will probably find I don't have any strong feelings about the value of information. I find it simply information. If I read an engineering paper, a chemical optimization paper, or a paper on a new reaction, the low yielding results are just as valuable as the high yielding results. I don't look at a series of reactions and think, "that yield was rather low, they should not have included it." I don't ignore what problems a synthesis encountered and contributed to the eventual solution. It is just data and it may be valuable (or not).

I am quite aware of the conflict between academic and industrial research, I have done both, but, really, patents have more merit than green chemistry? Re the green route, burn the ethanol to heat the water? I don't know. Perhaps that have a hot tube in which the hot water is recycled, it's just engineering? (Remember, I am just a low level flunky chemist, what do I know?)

I have changed the highlight color of curiouscat's original post. I felt it was the ratios that brought this to his or her attention, but maybe I'm wrong. Perhaps it really was about "green chemistry" and I've missed the point.

[DrCMS]

The authors of the paper curiouscat quote were proclaiming their route to be green.  Given the large amount of water needed and the high temperature and therefore pressure required I stated they were talking bollocks.   I stand by that statement their route may be novel but it is not greener than the routes already reported in the literature.   I feel that the editors of Green Chemistry should have rejected the claims the authors made.  It might still merit a publication of this did not work but it should not have been published on the basis of being an improvement to existing methods.

[Enthalpy]

Phthalaldehyde must react at two sites
with also two sites of 1,4-cyclohexanedione
to produce 6,13-pentacenequinone.

As I imagine the reaction:
- Under high concentration, one oxygen of phthalaldehyde would react with two hydrogens at one site of 1,4-cyclohexanedione... But then, the other oxygen would meet an other molecule of 1,4-cyclohexanedione and react with that instead. The result would be a polycondensate.
- At moderate dilution, they would get an oligomer, possibly a cyclical one.
- Only under vast dilution has the partly reacted phthalaldehyde the opportunity to react at its second oxygen with a second site of the already linked 1,4-cyclohexanedione before meeting an other 1,4-cyclohexanedione.


Worse, the sites at phthalaldehyde have a "natural" spacing (5 bonds) that differs from that of 1,4-cyclohexanedione (1 bond), so the proper conformation of phthalaldehyde is seldom available. I imagine that different function distances favour polycondensation a lot when producing polyamides and polyesters intentionally. Conversely, avoiding the favoured polycondensation demands the huge dilution.

Warning: I'm far here from anything I believe to understand, so please
- take with caution
- forgive me if I put nonsense.

[curiouscat]

@curiouscat

World War 3? This? You haven't been around the internet much, have you? Hell, seeing as Hitler or the nazis haven't been brought up yet, this isn't even a proper argument yet.

@corribus You are right! 

Out of curiosity, if you have published any synthetic papers, what were the concentrations of reagents you used? Or in papers you read.

I keep bumping into papers with below 0.5% (w/w) concentrations and it makes me wonder how much of actual synthetic chemistry happens at these dilutions.

Maybe industrial chemists have some datapoints too..

[eazye1334]

World War 3? This? You haven't been around the internet much, have you? Hell, seeing as Hitler or the nazis haven't been brought up yet, this isn't even a proper argument yet.

You just Godwinned the thread by bring up Godwin's Law! That's so...meta 

[Corribus]

@Curious

I had to go back and look, but as an example of one reaction:

10.2 mg reactant A (0.0108 mmol) + 12.3 mg reactant B (0.0123 mmol) + 1.5 mg catalyst (0.10 mol eq.) + 7.0 mg co-catalyst (2 mol eq.) in ~7 mL solvent (6:3:1 acetonitrile:THF:triethylamine) yielded typically 10-15 mg product in 60-70% yield. The reaction was run at about 60 C under inert atmosphere for 8 h, purification on silica with MeCN, water and saturated potassium nitrate as eluent.  That's about 5.6 grams of solvent for a total of 31 mg of reactants.

For our coupling reactions we usually tried to use as little solvent as possible to dissolve everything.

Granted: I am not an organic chemist by any stretch of the imagination. I basically used conditions suggested by other people in the lab more knowledgable than myself and I didn't really think too much about why I was using certain reagents.  Definitely wasn't my thing. I made enough to do what I needed on the laser and so didn't really give a crap about yields or optimizing conditions, so take that for what it is.

[curiouscat]

@Curious

10.2 mg reactant A (0.0108 mmol) + 12.3 mg reactant B (0.0123 mmol) + 1.5 mg catalyst (0.10 mol eq.) + 7.0 mg co-catalyst (2 mol eq.) in ~7 mL solvent (6:3:1 acetonitrile:THF:triethylamine) yielded typically 10-15 mg product in 60-70% yield. The reaction was run at about 60 C under inert atmosphere for 8 h, purification on silica with MeCN, water and saturated potassium nitrate as eluent.  That's about 5.6 grams of solvent for a total of 31 mg of reactants.

Ha! 0.55% then. 1:180 dilution.

Granted: I am not an organic chemist by any stretch of the imagination. I basically used conditions suggested by other people in the lab more knowledgable than myself and I didn't really think too much about why I was using certain reagents.  Definitely wasn't my thing. I made enough to do what I needed on the laser and so didn't really give a crap about yields or optimizing conditions, so take that for what it is.

Sure. I'm perfectly fine by studies like yours using whatever dilutions they prefer: Your goal isn't a better synthetic pathway.

It's perfectly fine to use exotic conditions and make a novel compound, or get a new spectra, or elucidate a mechanism, or evaluate thermodynamics or just make an interesting fundamental observation or some such.

The papers that annoy me are those using impractical reaction conditions and then selling it as a better (cheaper / faster / greener etc.) route. That to me is inexcusable.

Take the example of the paper I mentioned in my original post. I've now read its details and it does not even mention or justify or point as a drawback their highly impractical dilution (hope I didn't miss it!).  I think that is where the fault lies.

So I guess I still disagree with your opinion (if I understood it right!) that  per se nothing obviously detracts from that paper's publication in "Green Chemistry". The fact that those authors, editors and reviewers thought there's nothing odd about it makes me pause. And perhaps worry. Maybe there are some systemic issues here.