ldanielrosa
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triacetin synthesis
I'm trying it on a lark. I put 23g glycerol and 45g acetic acid (glacial) in a beaker with 0.5mL conc. sulfuric acid and just enough water to clean
the glycerol out of the weigh boat.
I had it on the stirrer for a while on low heat. It's hard to tell how well it's doing. I didn't find much on it, but I didn't look that hard
either. Maybe I'll put a drop of food coloring in it to give a visible division between the aqueous and organic phases.
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ldanielrosa
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Failed. Zero product. I'll have to research this one and may need equipment I don't have yet.
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madscientist
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Thread Moved
28-2-2011 at 16:55 |
Nicodem
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Quote: Originally posted by ldanielrosa  | | I'm trying it on a lark. I put 23g glycerol and 45g acetic acid (glacial) in a beaker with 0.5mL conc. sulfuric acid and just enough water to clean
the glycerol out of the weigh boat. |
Have you forgot that the reaction you talk about is an esterification?
Reactions occur at the required reaction conditions. Did you provide the reaction an opportunity to proceed? You don't give any references, so we can
not even be sure you are aware of how this synthesis is done and what are the required reaction conditions.
Next, esterifications are quite equilibrium reactions. If you introduce water in the reaction mixture, the equilibrium constant changes.
| Quote: | | I had it on the stirrer for a while on low heat. It's hard to tell how well it's doing. |
That is exactly why chemists use various methods of monitoring reactions. The simplest way in this case is to monitor the reaction temperature while
on reflux (but how much this tells depends on the amount of excess acetic acid present).
| Quote: | | I didn't find much on it, but I didn't look that hard either. |
It would not be that hard. If you only tried, you would found the Kirk-Othmer chapter on esterifications on this very forum. That would be the basic
read. Next, find an article with the experimental procedure for this very synthesis.
| Quote: | | Maybe I'll put a drop of food coloring in it to give a visible division between the aqueous and organic phases. |
A solution is a monophasic system!
You can only have liquid-liquid biphasic systems if two liquids (or two solutions) do not mix, for example: methanol/heptane, water/toluene,
acetone/brine, etc.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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ldanielrosa
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Thanks for your input Nicodem, I wasn't really being professional about my methods so I didn't stake high expectations on my experiment.
"Have you forgot that the reaction you talk about is an esterification?"
Not at all. It got my attention because it is the smallest possible digestible (synthetic) fat. Apparently I didn't provide the opportunity that the
triacetin needed on it's terms. I'm not surprised that esterifications are equilibrium sensitive. I had hoped to get some indication from it under
the conditions available, but the reactants are cheap enough that I'm not heartbroken.
Unfortunately I don't have the space or money to use or obtain any real distillation equipment at the moment, so everything has to be open container
on a hotplate stirrer.
Thanks for the lead.
I had assumed that as a glycerol ester, it would be biphasic with water.
Will this require access to "References"?
[Edited on 5-3-2011 by ldanielrosa]
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Eclectic
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It boggles the mind how many times Wikipedia has had this phrase blindly copied:
Triacetin is also a component of casting liquor with TG.
Does anyone have a clue what kind of casting resin this is and what "TG" is?
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watson.fawkes
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| Quote: Originally posted by Eclectic | It boggles the mind how many times Wikipedia has had this phrase blindly copied:
Triacetin is also a component of casting liquor with TG.
Does anyone have a clue what kind of casting resin this is and what "TG" is? |
From what I can tell, that
phrase is commercial spam from http://www.reactchem.com/, a Chinese manufacturer of the stuff. I saw other paraphrases of this line, but with their web site address. The casting
liquor seems to be for contact lenses. I don't have any idea what TG is though.
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