Howdy Pardner....
bob allen wrote:
Howdy Joe (I just had to write "Hey Joe" before. its the lead to a
Jimmy hendrix song I enjoy.)
Yeah I get that a lot. When they ask me "where you goin with that gun in
your hand" I say "This is my rifle and this is my gun, This is for
shooting and this is for fun"
Ok thanks for your corrections and information below. As a chemist you
are a boon to this list. Have you given any thought to the other thread
about using some form of energy input to make the esterification
reaction go? Apparently it can be done with a high electric field
strength and passing the oil/alcohol mixture at elevated temperature
(and pressure I am guessing since the vapor pressure of methanol at 85
deg C must be above atmoshpere). I was also wondering about using
intense UV light. Any thoughts?
Joe
more below
Joe Street wrote:
Hi Bob; see comments below.....
bob allen wrote:
Hey Joe,
Joe Street wrote:
Where is the toxicology?
For those on the list unfamiliar with MSDS (Material Safety Data
Sheet) and the terminology this is what is missing
no LD50 (lethal dose for 50% death rate -usually tested with rats)
no LC50 (lethal concentration for 50% death rate)
There may not be data on sodium methoxide due to its reactivity: in
the body it quickly (essentially instantaneously) equilibrates to
sodium hydroxide and methanol.
Well I don't know if it is that simple.
for my example yes. when you combine sodium or potassium hydroxide
with methanol, you establish an equilibrium:
sodium hydroxide + methanol --> sodium methoxide + water
addition of water such as occurs in vivo, forces the equilibrium back
to the left.
For example I am familar with
TMAH (TetraMethylAmmonium Hydroxide) which is essentially Methanol
and Ammonium Hydroxide
no, not by a long shot. Tetramethylammonium hydroxide has a formula
of C4H13NO. It is chemically quite different than a mixture of
ammonium hydroxide (it self an equilibrium mixture of water, ammonia
and ammonium hydroxide) and methanol.
which is used as a modifier in semiconductor chemical
etching processes. The MSDS lists a drastically different toxicity
for the METHANOL component approx 5000 ppm vs the TMAH at only 25
ppm. See: http://www.jtbaker.com/msds/englishhtml/t1816.htm
I am no chemist
I am
and I don't know if it is fair to make this comparison
since
not here
we are talking about ammonium hydroxide instead of potassium
hydroxide but clearly the compound is much more toxic than the sum of
its components.
you're comparing oranges and apples. I spoke of a simple mixture
NaOH/MeOH and you are talking about a compound (CH3)4 N (+) (OH)-
and more importantly
no TLV (Threshold Limit Value which relates to the maximum
allowable exposure before serious health effects appear due to
daily repeated exposure)
no OEL (Time Weighted Average (TWA) which refers to what someone
decides is an acceptable concentration which a worker can be
exposed to over a working shift time period)
TEL and OEL as far as I am aware relate only to volatiles. Sodium
Methoxide is a hygroscopic solid, hence no data.
The methoxide that I make by mixing 99% methanol with 85% assay KOH
is volitile and definitely liquid.
You are making a mixture, the volatile component of which is still
methanol
So I would think it should be of
interest. The datasheet we found for sodium methoxide refers to a
solid you are right but that just shows the relevance of the comments
from before that one must know something in order to even read an
MSDS and even then it may be of limited value. You are right though
it is still the best info we have. I just think it is sad that the
documentation does a very poor job of what the legislation ( or the
intent behind the legislation) was supposed to accomplish which is to
provide meaningful information to protect workers who have to handle
hazardous subtsances.
If you dug around long enough you may find a supplier of the mixture
you are preparing. If they sell that mixture, then they have to have
a MSDS on it.
In this case (methoxide solution), use the methanol component msds for
things such as an LD50 or TLV and the NaOH or KOH msds for other
risks, such as extremely caustic, etc.
It is an echo of the type of situation so often discussed in this
forum where legislation which is supposed to protect people ends up
having gaps and loopholes that allow big industry to go on with
little more than a nod to regulations and the rest is status quo.
Still it is better than no information. But not much better. I have
worked with proprietary formulations of liquid teflon from dupont
which required so many promises of non disclosure and confidentialty
you would almost wonder if they really want anyone using the stuff
and then when you finaly get it and read the MSDS it tells you there
are proprietary elements which are undisclosed. The technical
information sheet included with the bottle gives explicit
instructions on how much exhaust and protective equipment is needed
and leaves you with a sense of fear of the unknown, but yet there it
is on the market for anyone who can afford it. Lip service. That's
all it has become. Business as usual.
no real disagreements here...
toodles
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