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kristofvagyok
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Real chemistry is dying out, why?
Dear everyone,
Lot of you know my work, you know that I work in an orgo lab with real amounts, but I am confused, does my work have a future? Every journal what I
open has awesome experiments, 99% yields with amounts like mmol, mg, and such like it. They measure the reagents with hamiltons and micropipettes and
they call it chemistry.
My question is: WHY?
I know that small amounts are cheaper to work with but with 1-2mg? The only thing what conforms the reaction is a little peak in the NMR spectra what
could be anything else also.
This was my last reaction (last week made), it was started with 1 mol, currently I have circa 700mmol from it and I had performed 3 steps, this means
300g raw product in that beaker up there what is 8000cm3 large, and I simply love to work with this large amounts.
So if anyone have an opinion about this, pro or versus please tell it.
P.S.: Every time when I tried to scale up a reaction from 1mmol to "workable" amounts it simply didn't worked...
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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Hexavalent
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I appreciate that the costs are less, but surely accuracy and precision go down at some point when working with increasingly small amounts?
Personally, this weekend I've just recrystallized 1kg of urea from a commercial de-icing product....finally got to use my 3L erlenmeyer
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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kavu
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In academic settings running reactions in large scale is costly and produces a lot of waste. Usually method development is easier to do in smaller
scale. I'm also somewhat involved in total synthesis and we just don't have enough starting material to waste. In all work first start small and then
do the scaleup. Easier to handle, no runaway reactions, no large and expensive glassware and so forth.
[Edited on 7-10-2012 by kavu]
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kristofvagyok
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Small glassware is also expensive, runaway reactions are rare, I didn't have any in the few years... The solvents and the reactants are usually not
that much more expensive in larger amount. E.G.: 25cm3 benzyl alcohol is just 5 USD cheaper than 100cm3, because the glass what is it cost's more.
The waste recycling is the biggest deal, but with a proper solvent redistilling and re-usage this could also reduce the price of this...
So: small chemistry is NOT CHEAPER!
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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Siggebo
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As a half-serious remark, I have troubles working even in semi-micro scale because of shaky hands.
And I don't even drink coffee.
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kavu
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Let's say that you have a linear sequence of 25 steps in your synthesis with a 80% yield in each step. If you want to do this on a large scale it will
cost you a LOT. It depends on what you are doing, in total synthesis large scale is in most cases out of question. I've also been working on
organocatalysis where large quantities are needed.
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Tsjerk
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When you are working with stuff like benzyl alcohol, it doesn't really matter how much you take... But if you are doing a novel 7 step synthesis
starting with some expensive terpinoid, you will end up working in the milligram range at some point.
I did a couple of projects working with small amounts. But while I was working with 50mg at most at some points, the total cost of that amount was
several thousand euro's, because of all the expensive reagents and liters and liters of solvents used in chromatography purification after each step.
So small scale isn't cheaper perse, but in some cases you don't have a choice, especially when working with large organic molecules and doing multiple
step synthesis with them.
Edit: What Kavu says, and a lot of chemists would give up a finger for a 80% yield in every step.
[Edited on 7-10-2012 by Tsjerk]
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Sublimatus
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I worked in a university lab in the 0.3 to 1 gram range.
Our lab wasn't exactly wealthy, and many of our starting materials were rather complex. It was generally easier to buy those initial compounds from a
company synthesizing them on a large scale for relatively cheap, rather than spend two months to get their ourselves.
That said, when 5 grams of your starting material costs $400, it makes more sense to do the research on a small scale. Botching the synthesis
somewhere along the long series of manipulations could be a costly mistake, especially if you blew the whole 5 grams on that one attempt.
One should also consider that disposal of hazardous waste generated during lab work can get expensive. Working on a large scale naturally produces
more waste, and if your kilo of expected-to-be product goes south during a manipulation you'll be paying to try again and to get rid of the mess.
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triplepoint
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Quote: Originally posted by Siggebo  | As a half-serious remark, I have troubles working even in semi-micro scale because of shaky hands.
And I don't even drink coffee. |
It's not a joke. Macroscale reactions are easier to perform. It is easier to see what you are doing and easier to be adequately precise in all of the
mechanical actions necessary to perform chemistry.
From a raw materials and equipment perspective, micro is often more efficient, but that efficiency comes at an additional cost to the experimenter.
Micro is sometimes more reasonable or even the only way to go, but the human costs should not be disregarded.
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kristofvagyok
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| Quote: Originally posted by kavu |
Let's say that you have a linear sequence of 25 steps in your synthesis with a 80% yield in each step. If you want to do this on a large scale it will
cost you a LOT. It depends on what you are doing, in total synthesis large scale is in most cases out of question. I've also been working on
organocatalysis where large quantities are needed. |
Total synthesis is an expensive thing, I agree, catalyst and any other "modern" chemical way is also expensive, but if the reaction route what have
been worked out is just good for mg scale than it is useless. To optimalize it to "workable" amounts will be as hard, or even harder to perform than
the microscale synthesis.
But if everywhere they work with microsyngres and stuff like that who will make the "normal part"? If there is a good project than it would be good to
make it in useable amounts.... Or just bigger than an NMR sample.
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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kavu
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This is merely dependent on what the goal of the research is. If you want to have a preparative route to a compound, yes a good scaleable route is
your choice. If you are however interested in screening a reaction, doing physical organic chemistry, total synthesis and so forth you don't have to
go that far. In most cases the most expensive thing is paycheck of the chemist. Right Tool for the Right Job works in synthesis as well
Scaling up is a huge part of chemistry and in industry many chemists specialize in optimizing routes to be used in large scale. This is really a
demanding job and requires a rigorous analysis of different aspects of a reaction. It's not dying out as far as I know, quite the opposite. As
synthesis develops we get new materials and the pilot synthesis of these requires this "real chemistry".
[Edited on 7-10-2012 by kavu]
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Sublimatus
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You're right that eventually someone will have to figure out a large-scale route if the compound proves to be commercially viable.
The issue, though, is that it makes little sense to invest so much in a compound until its utility has been demonstrated. Where I worked we were
systematically investigating new compounds to be used as MRI contrast agents. It would have been prohibitively expensive to synthesize on a large
scale each compound that we checked. We screened a ridiculous amount of structures and motifs in search of something suitable. Nearly all of them
were not up to snuff, so there would have been no return on invest toward the material cost.
It's difficult to receive grants for research in many fields these days, so we have to make the most of what money we can get. If you have the luxury
of not facing monetary concerns, know that there are many bench chemists who would love to be in your position.
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sargent1015
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While I love macroscale, I do know that some of the compounds in my lab are over $1000 per gram, not ideal if you want to perform even a 1 g scale
synthesis
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froot
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I would also suggest that it has much to do with the growing awareness of the health hazards from exposure to countless compounds. Smaller quantities
are easier to crisis manage and dispose of without major expense. The newer school of thought: "if it's toxicity is unknown, then it's deadly" springs
to mind which is not exactly in favour of old style bench top chemistry.
We salute the improvement of the human genome by honoring those who remove themselves from it.
Of necessity, this honor is generally bestowed posthumously. - www.darwinawards.com |
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Dr.Bob
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A lot of scale depends on the purpose. If preparative, or for in-vivo testing, then you must scale things up. But 10 mg of a compound can provide
enough material for many biological screens, anywhere from 100-1000 high throughput binding screens, or dozens of other assays. And while I am the
first to agree that it is nice to have more material ready should a hit be found, the likely answer is that it is very expensive to store 1,000,000
vials of material.
I try to scale up common intermediates to a few grams or more, if they are useful for multiple reactions or steps, but most organic chemistry I do is
now in the 100 mg to 2 gram scale. The cost for some materials may be cheap, but silica gel is not cheap, and most reactions require purification,
so scale costs there, in chromatography silica or recrystallization solvents.
As for "does my work have a future?" that is more a question of free trade and cheap labor. China can provide cheap chemists, cheap energy and raw
materials, and little regulations, all of which are what are killing jobs in the US and Europe, along with MBAs, lawyers, CPAs, banks, "free trade"
and politics. I am the first to want to protect my safety and the environment, but the current desire for everything to be "100% safe" and
"absolutely no chemicals" is killing industry in the US. That is what will determine your work future.
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kristofvagyok
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| Quote: Originally posted by sargent1015 | | While I love macroscale, I do know that some of the compounds in my lab are over $1000 per gram, not ideal if you want to perform even a 1 g scale
synthesis |
Sigma sells the stuff what is in my beaker at price 200usd for 5g. Calculate 
I agree that every "extreme" price compound couldn't be synthetised in bulk quantities, but if everything is performed in micro scale... It is also
not the best.
| Quote: Originally posted by froot | | I would also suggest that it has much to do with the growing awareness of the health hazards from exposure to countless compounds. Smaller quantities
are easier to crisis manage and dispose of without major expense. The newer school of thought: "if it's toxicity is unknown, then it's deadly" springs
to mind which is not exactly in favour of old style bench top chemistry. |
I work with benzene, CCl4, chlorine, bromine, brucine, several organic halogens, carcinogen stuffs and a lot "hazardous" material and I'm still
alive. If everyone is a pussy to work with real reagents then I would suggest to don't work as a chemist. Chemistry is about hazardous materials, just
don't be afraid from it and there will be no problem, according to my experiences.
And for the "new school thought", that if it's unknown it will kill you... No comment.
I have a blog where I post my pictures from my work: http://labphoto.tumblr.com/
-Pictures from chemistry, check it out(:
"You can’t become a chemist and expect to live forever." |
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Magpie
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As strictly a home chemist, I like to work on the scale of a few grams. I keep it small to minimize materials, equipment, waste management, and
risk. But if I had to work with just a few mg or less I would get no satisfaction from it.
My old school lab manual (1960) has about the right level of macroscale for me. However, when using a procedure from OrgSyn or Vogel, I will usually
scale it down.
The single most important condition for a successful synthesis is good mixing - Nicodem
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woelen
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@Magpie: In home chemistry it hardly is possible to work on true microscale with just a milligram of reagent. I like to do my experiments on a test
tube scale, which means that I use a few ml of solvent (in most cases this is distilled water) and 50 ... 500 mg of reagents, the precise amount
depending on properties like solubility, price and intensity of color.
Synthesis of new chemicals I usually do at a scale of 10 grams, sometimes a few grams, sometimes a few tens of grams.
Too small a scale makes yields nearly zero. Mechanical losses are fairly constant and if I make 1 gram of a compound and 500 mg sticks into a filter
and cannot be scraped from it then the mechanical loss is 50%. If I make 10 gram and I still have 500 mg sticking to a filter, then the mechanical
loss is only 5%. The same is true for distilling volatile liquids. E.g. when I use a 100 ml flask and I distill 5 ml, then quite a high percentage is
lost as vapor, while in distilling 50 ml the same loss is a 10 times lower percentage. So, in general I try to do a synthesis on a minimum scale, with
the constraint that mechanical losses should remain acceptable. A mechamical loss of 10% is something I can live with, but a loss of 50% is too bad
for me.
With mg quantities my mechanical losses would be nearly 100% (or even completely 100%), simply ebcause I do not have the equipment to handle such
extremely small amounts.
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arsphenamine
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I appreciate that working on a micro scale is ungratifying by its seeming abstract nature.
Sometimes you just want to blow shit up for the unambiguously palpable thrill.
Those little bumps in the NMR spectra usually coincide with other spectral data,
most of which may be computationally approximated so that you know what to expect.
Macro-scale preparative chemistry has the disadvantages of cost and hazmat disposal.
If you review Woodward's total synthesis of chlorophyll,
you infer a proliferation of false turns in the process, and
reach the glum realization that he started with a drumfulls of feedstock.
In the last para, the phrase ...performed Herculean preparative tasks.. stands out.
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Ozone
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Four words: "Office of Risk Management".
The intrinsic risks associated with the teaching and practice of Chemistry cause fear of legal retribution. This is used by policy makers and/or
campus officials looking to save money buy minimizing perceived risks. Not only is chemical-free Chemistry cheaper, but it is also safer, ergo win-win
for the politically expeditious bureaucrat-trolls in charge. The public approves of this because they are ignorant and believe that the "use of
advanced technology and information science" will keep them, their 18 year-old "children" and the environment safe.
These are the same people who are excited about "virtual labs". No chemicals = no risk. It also equals "no practical experience". I am already running
into people with degrees in Chemistry who are scared to death of...chemicals. Even "seasoned" Chemists and Techs seem the wet their pants over
dichloromethane.
Worse, the same fears (propagated by the EPA, DHS, etc. and years of public ignorance) have made the practice of Chemistry (indeed of most "scary
science") practically illegal outside of the institution.
It's sad and it's going to get worse.
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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elementcollector1
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| Quote: Originally posted by Ozone | Four words: "Office of Risk Management".
The intrinsic risks associated with the teaching and practice of Chemistry cause fear of legal retribution. This is used by policy makers and/or
campus officials looking to save money buy minimizing perceived risks. Not only is chemical-free Chemistry cheaper, but it is also safer, ergo win-win
for the politically expeditious bureaucrat-trolls in charge. The public approves of this because they are ignorant and believe that the "use of
advanced technology and information science" will keep them, their 18 year-old "children" and the environment safe.
These are the same people who are excited about "virtual labs". No chemicals = no risk. It also equals "no practical experience". I am already running
into people with degrees in Chemistry who are scared to death of...chemicals. Even "seasoned" Chemists and Techs seem the wet their pants over
dichloromethane.
Worse, the same fears (propagated by the EPA, DHS, etc. and years of public ignorance) have made the practice of Chemistry (indeed of most "scary
science") practically illegal outside of the institution.
It's sad and it's going to get worse. |
I'm writing an essay on this topic, in fact. Hopefully my English class will listen to the 3-page, 6-paragraph rant I have prepared for them. 
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Ozone
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Please post it here.
Cheers,
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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bfesser
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kristofvagyok, are you trolling us, or are you really as ignorant as you're making yourself out to be?
What's cheaper, 1 gram of chamazulene, or 5 kg of it? A 5L beaker, or a case of 5 mL beakers? Seriously, look it up. Don't confuse your lack of
skill and knowledge in microscale chemistry, with an inferiority in the established techniques.
Basically, what I'm saying is; your 'argument' is idiotic and uninformed.
[Edited on 1/16/13 by bfesser]
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woelen
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I summarize my way of working as follows: "As micro as possible". I prefer to use small amounts (and yes, it IS cheaper to use small amounts), but the
amounts should not be so small that I hardly can handle them anymore and hardly can see what is going on.
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kmno4
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This is what I was going to write.
Just plain trolling.
ps. mg-scale procedures are very often not scalable to multi-gram preparations; besides, some procedures and yields exist only on paper and no-one is
able to confirm them.
Слава Україні !
Героям слава !
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