bereal511
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Experimental Organic Compound
I'm doing a project on the dropping concentrations of an organic compound under certain conditions. But I'm having a problem trying to find a
suitable organic compound for part of the experiment. It should fall under these conditions:
- relatively cheap
- easily obtainable (does not need licenses, industrial orders, or bulk orders)
- low volatibility (where if you were to leave it in the sun for a week, only a fraction would have evaporated)
- easily indicatable (sp.) using techniques that are relatively cheap and accessible
- does not readily react with metal oxides
- soluble in water
- preferably does not chemically rape plastic, but if it does, no problem
Thanks for any input, I really appreciate it.
[Edited on 15-11-2006 by bereal511]
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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DDTea
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How about Ethylene or Propylene Glycol (Antifreezes)? The only problem is they come premixed with water; however, they meet all your criteria. Their
boiling points are quite high, and they are nice and oily and it's about the time of year where you'll find them all over shelves of K-Mart or even
the right part of a grocery store.
They are soluble in water, will not react with plastics... The only issue I can think of is indicating. There are several reactions that can be done
with alcohols; one of which is oxidation to an acid.
Maybe you could do your indication step each day by taking a sample from your "master liquid," adding a predetermined amount of Potassium
Permanganate (another over the counter oxidizer found in hardware stores; strong enough to oxidize an alcohol all the way to a carboxylic acid), and
then using pH paper to get a rough estimate over time? But then this would only work if it's being done in water..and if it's being done in water,
the water would probably evaporate off long before the Ethylene/Propylene glycol, leading to an *increasing* concentration of the organic compound
over time..
Just my stab at the problem; anyone else want to try?
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
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bereal511
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Evaporation of water isn't so much of an issue mainly because I'll be adding equal amounts of water that is loss to evaporation over the period of the
experiment.
The antifreeze idea sounds pretty good with the potassium permangante. I just hope that I can either 1.) purify the antifreeze enough to use in the
experiment or 2.) find a supplier of propylene glycol. Price isn't so much of an issue, I just don't want to be dishing out hundreds of dollars for a
few liters of the stuff.
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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Tacho
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A compound with a phenol group would be very easily detected using ferric chloride, easily found in electronics shops as etching solution for printec
circuits. The reaction is sensitive and yields a very visible color change or precipitate.
Eugenol becomes a water-soluble phenolate in alkaline solutions, but I don't know if the phenolate reacts with ferric chloride in the same way.
Phenol itself is water soluble to a certain extent. But I think it's volatile and not very recomendable healthwise.
Can't think of any other easy to find phenol right now. Anyone?
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DrP
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| Quote: |
- relatively cheap
- easily obtainable (does not need licenses, industrial orders, or bulk orders)
- low volatibility (where if you were to leave it in the sun for a week, only a fraction would have evaporated)
- easily indicatable (sp.) using techniques that are relatively cheap and accessible
- does not readily react with metal oxides
- soluble in water
- preferably does not chemically rape plastic, but if it does, no problem
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Sugar / Urea / Urea phoshpate (Are water soluable solids)
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Tacho
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Hydroquinone is a water-soluble phenol and also a reducing agent that has many easy indicating reactions. Some (at least one from Kodak) photo
developers have a high hydroquinone content.
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Tacho
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I just tested eugenol dissolved in alkaline water (with NaOH) and it gives a dense precipitate when ferric chloride is added.
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DDTea
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How exact do your measurements have to be for this project? What I mean is, to what extent is this quantitative vs. qualitative; because measuring
varying concentrations of a compound in solution over time based on color or pH will require at least mildly involved calculations...and the proper
equipment, needless to say.
This will only be amplified if you do an intermittent reaction such that you *can* take measurements (introduce more human error)
So you might want to consider another factor: "easiness"--which chemical and measurement technique makes your life easier.
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
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Elawr
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Glycerol .
1
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bereal511
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Hmmm, I'll take your point into account Samosa. The exactness of the project can be varied on my part. Ideally, I'd like to be able to measure the
organic compound quantitatively, but if it cannot be done with potentially large errors, then it probably wouldn't be worth the trouble.
I'm working on this in a high school laboratory setting and I currently have $500 at my disposal. It'd probably be best just to do a simple
indication step to show that the organic compound is still present within the mother liquor until its concentration reaches 0.
And Elawr, I also thought of glycerol as a potential candidate, but I'm having trouble thinking of a way to measure its concentration in water. Care
to elaborate?
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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