Mothman
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Anthocyanins Extraction (and pleasant smell of fall leaves)
So a few weeks ago I noticed a leaf from a tree in my front yard had fallen into a small dish of hydrochloric acid that I was using to dissolve tin in
and the color of the leaf had leached into the solution, turning it pink. Having had my curiosity piqued I decided to do further research into the
responsible compound(s) and I determined that it was likely anthocyanins. I had always loved the beautiful red color of the tree that that specific
leaf had come from and there were still leaves on it in spite of a windstorm having come through recently. The leaves had dried to a crumbly texture
on the branches and so I went out one night with a mason jar and I collected as many leaves as I could, making sure they were still vibrantly colored
and not brown. After collection I looked into extraction procedures for the colors in fall leaves and decided I would just use hardware-store acetone
as the solvent. This was poured into the leaves enough to cover them and then I stirred the leaves around to remove any air bubbles. I put the lid
back onto the jar and then I let it sit for about two weeks, occasionally I would shake it a bit and hold it up to the light to check the color of the
acetone, but otherwise not much was done to it. When the solution had reached a clear, deep orange-amber color I filtered it into a 1000 mL
roundbottom flask using a coffee filter. I noticed two things: 1.) the leaves were still very red, and 2.) a small amount of the acetone solution that
I had spilled had evaporated and left a pleasant smelling residue that brought back memories of when I would play around in leaf piles as a little
kid. It was at this point I decided to try to extract the smell of fall from these leaves, though I still do not know what exactly is causing it. The
smell extraction is still underway though, and I will detail my progress later on in this thread.
I took the still red leaves that had soaked in the acetone and I decided to do a water extraction of the anthocyanins, as the acetone had clearly
failed. I covered them in distilled water and let it sit overnight. I noticed upon the addition of the water a turbidity that was not present with the
acetone at any point, so I decided to pour about 230 mL of water into the flask of the acetone solution to see if anything would crash out.
Immediately upon addition of the water there was noticeable cloudiness and after a small amount of agitation the solution became a milky orange color.
I let this settle over the course of last night and this morning it became apparent that there were two phases (top being turbid white and the lower
one being a light orange) in the flask and a lot of whiteish precipitate resting on the bottom of the flask. I have yet to explore the properties of
any of these phases but the smell of fall emanated from the spots of acetone that had evaporated even after filtration and so I can only assume it is
in some part of the flask, whether or not it is still in the acetone is to be determined. In regards to the red color from the leaves, much of the
color had leached into the water, leaving the leaves a sort of grayish-white color with pinkish spots and red stems. I proceeded to filter off the
leaves and I washed them with about 100 mL of distilled water to make sure that the dye was fully washed off. I am currently in the process of letting
it settle out and filter. I will be removing the water from the solution via simple evaporation and I will be reporting back here as soon as that is
done. For those of you wishing to try this, I will outline the procedure I used below:
Step One: Collect a lot of leaves of the color you desire.
Step Two: Pack the leaves into a jar and then cover them with acetone, I used hardware store, straight-from-the-jug acetone for this step.
Step Three: Stir or shake the acetone solution to make sure that it is thoroughly mixed.
Step Four: Let the mixture sit for two weeks or until the color of the solution doesn't appear to be changing. My solution was a deep orange when I
finally stopped the acetone soak.
Step Five: Filter off the acetone solution and then cover the leaves in distilled water. I did not allow the acetone to evaporate off of the leaves so
there was still a little remaining in the jar.
Step Six: Allow the leaves to soak in the solution overnight.
Step Seven: Filter off the leaves once they appear to have lost most of their color and discard them.
Following these procedures will result in an orange solution of acetone that makes stuff smell like fall, and a solution of anthocyanins and other
compounds. My solution was blood red as I began with red leaves, but IIRC anthocyanins are pH sensitive so other solutions may be of different colors.
I will be continuing to update you guys on my progress with this. If anyone has done this sort of thing in the past I would love to compare notes on
this endeavor.
You can be happy
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arkoma
Redneck Overlord
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I am pretty w3ell "in my cups" at the moment, but anthocyanins were one of the things that drug me into amateur chemistry
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
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Texium
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Hey, congrats on the thousandth post there Pat!
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Texium
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Thread Moved
14-12-2017 at 18:01 |
Mothman
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Well I guess I posted in the wrong neighborhood...one of these days I'll be posting with the cool kids in the Biochem section, one day! 
Ok, back to the topic at hand:
I decided to wash the red leaf extract with toluene and I am currently letting it separate out. I don't know how necessary this step was but I don't
see how it could hurt anything. Next I'll be adding acetone to the solution to see if I can make the anthocyanins crash out, as they didn't seem too
soluble in the acetone in the first place, though there was not a lot of water in the acetone the first time around, I might just try this with a
smaller sample to see what happens...
In regards to the acetone extract, the layer separation appeared to be an illusion created by the precipitates. They have fully settled out though the
solution still appears rather cloudy so Ill give it another 24 hours before filtration.
You can be happy
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barbs09
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hee hee "extract the smell of fall", I was instantly reminded of Jean-Baptiste Grenouille's pursuit in Patrick Süskind's uneasy but great novel
"Perfume: The Story of a Murderer".
I too love the earthy smell of autumn, which I always though was attributed to geosmin amongst other volatiles. Good luck with your pursuits!
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Mothman
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So the toluene wash made some white crud appear, and the whole batch lost it's pure, clear red color. I would not recommend the toluene wash. I
suspect that the toluene absorbed the last of the acetone leftover from the leaves and caused stuff to fall out of solution. I couldn't manage to
filter this stuff out, so I disposed of the anthocyanin solution and burned off the toluene. I still have a bunch of acetone leaf extracts to deal
with. I think I am going to gather more leaves from the tree and skip the acetone soak for the sake of saving materials and time. I suspect I'll be
working against bacteria this time, but I recently got a working minifridge from a dumpster so I think that that will buy me enough time to extract
the anthocyanins and then see about crashing them out with acetone without interference from the bacteria.
You can be happy
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