quicksilver
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Erythritol & Mannitol
I have preformed some interesting experiments nitrating polyols and gotten some unique results. However I have some very basic questions. Erythritol,
when nitrated using a method Axt worked with, nitrates very well with a certain weight but not when scaled up....Erythritol has proven to be unique in
that recrystaliztion differs if alcohol or acetone is used. An alcohol recrystalzation results in a much finer crystal where as acetone
recrystalization results in a heavier granular product. Could someone shed some light on why refinement differs when using these solvents? [Times
& temps were the same in both re-crystalizations]
Mannitol has been _very_ challenging when using anything but a high percentage nitric acid. I have not been able to find a solid nitrate / H2SO4
combination that has proven to be effective. Others have claimed that they have done so w/ little problem....I would love to know what technique(s)
were used.
As much as I have searched and experimented all I have found is that mannitol nitrates well with high percentage HNO3 but seems to balk at solid
nitates and Erythritol has a "sweet spot" with solid nitrates ( at 12-15 grams ).
I realize that I am looking for concepts in nitration where there may not be any firm rules. That is, that these two materials may be relaed but
differ substantially in their needs. Erythritol and mannitol are so inexpensive and plentiful that nitration experiments using mixed solid nitatres
are a lot of fun as I am not concerned as to any cost factor when an experiment yields only data and little to no product.
Is there anyone who is familiar with a mixed acid (solid nitrate) nitration with mannitol that is consistent? Has anyone found Erythritol nitration
with solid nitates that can be scaled up or down with consistent yields? Ammonium nitrate / H2SO4 has given me a real challenge when utilizing
Mannitol. Has anyone found a method using solid nitrates that is consistent?
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chemoleo
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On the matter of crystallisation, this is a well-known phenomenon. Simple inorganic salts crystallise differently (with different space groups)
depending i.e. if tiny impurities or solvents are added. For instance, NaCl crystallises as cubes. In the presence of urea, it crystallises as
octaeders, even though urea is not part of the crystal structure.
The choice of solvent equally has a large effect on the crystal space group. It has to do with the hydration cage (or here, ethanol/acetone) which
form a loose structure around the nitrateester, which in turn affects the way it crystallises.
So much on crystallisation theory 
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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PHILOU Zrealone
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Different cristal structures may also imply different impact and heat sensitivities (read stability); cristal latice induces more or less stress and
is the major actor of density. The latest one being directly correlated to the VOD...
Scaling up is already a problem on its own since the volume increases faster than the surface...
In the case of mixed salts you get:
-High viscosity
-Solid cristals of salts and eventually of explosive
Those two implies lower yield of heat transfer between the cooling device via the surface and the reactive media.
Chances of runnaway by hotspots is thus higher.
To avoid this you have to:
-mix harder and faster ...what is no good idea with solid nitroesters subjected to friction against salts cristals
-play with the heat to increase solubility and diminish viscosity ...what is also a bad idea because on the edge of runnaway
Last options are to make:
-Euthectic mixes of several nitrates salts.
Than it is viscous but liquid.
-Use NH4NO3+ HNO3 (70%) and H2SO4 conc...to get a fluider batch of nitratants.
This makes the batch larger but it is also safer because the entire nitrating mix can be cooled freezing cold before adding the polyol...and most of
the nitratation heat being cought.
-The use of an inert or relatively inert solant towards polyols, HNO3, H2SO4 that could dissolve all reactants (no solids thus) in the cold and dilute
the system and diminsich viscosity... to prevent hotspots ...I would think to cetons or ethers kind of molecule, maybe DMSO...
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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quicksilver
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Very good stuff here: thank you both.
The hydration cage concept is something I was reading about some months back and completely forgot. 
When using KNO3 instead which was the original mixed acid synth I copied for Eyrthritiol I used 60g KNO3 added to 100ml 95% H2SO4 and cooled to 10°C.
15g Erythritol is added in portions, letting temperature jump between 10-20°C with each addition. Mix is left for 15min after last addition.
The mix, thick with crystals is poured (with some difficulty) into 1.5 litres water, a very fine precipitate forms and mostly floats to the bottom.
In some instances I also get a froth (temp of quence water variences).
15 grams - works well. scale up and yield goes to Hell.
The concept of using 70% HNO3 to "thin" the nitration solution is a very good one. makes sence. Going to get my calculator out after writing
this and work out the numbers.
And the DMSO concept....thats's interesting! 
I enjoy working with this type of nitration; I only wish that the mannitiol were as easy; it just seems "finnicky".....
[Edited on 2-12-2005 by quicksilver]
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Rosco Bodine
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There has been an experiment or two done by me to look at the nitration of polyols by first forming the sulfoester , and either adding the solid
nitrate to the sulfoester , or adding the sulfoester to an acid and nitrate mixture .
To get a general idea of the proportions required for the acid mixture , there is a chart in Urbanski IV which describes the conditions for PETN
formation using mixtures of free acids . The curves differ
somewhat for acid and nitrate mixtures ,
and unfortunately no charts specific for
mixtures using solid nitrates exist . And the optimum proportions are different for different polyols , but the proportions which work for PETN can
be used as a starting point and reference .
See the attached file from Urbanski IV
which I have edited to be a one page reference .
I have done one experiment using 92% H2SO4 and NH4NO3 which gave a 63% yield of recrystallized product . That could be improved I am sure by
optimizing the proportions and reaction times , and would probably go higher using sodium nitrate . I still am curious what urea nitrate would do if
used as the nitrate .
There is a related patent US1660651 and also US1691954 .
Attachment: PETN nitration graph.pdf (286kB)
This file has been downloaded 721 times
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Boomer
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I never had those problems when nitrating mannitol. While it *does* give better yields (90+%) with WFNA, AN+SA gives 50-60+% reliably *independant* of
batch size. While AN is slightly inferior to Na/K-NO3, it is soluble even in cold sulfuric, making it easier to work with (less hot spots, better
contact with mannitol --> less half-nitrated product which later dissolves in the bicarb).
One thing I found is that for such a thick sludge (both from unreacted mannitol and precipitated MHN), reaction times MUST be long. Overnight is good,
two *days* wont hurt either. Just keep it in the freezer, I once had a 1-liter-batch run away in the fridge at 10C! Could dump all my food except for
the canned beer, which I needed just then 
Will look up my notes at home for better figures, see you Monday.
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quicksilver
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| Quote: | Originally posted by Rosco Bodine
See the attached file from Urbanski IV
which I have edited to be a one page reference .
I have done one experiment using 92% H2SO4 and NH4NO3 which gave a 63% yield of recrystallized product . That could be improved I am sure by
optimizing the proportions and reaction times , and would probably go higher using sodium nitrate . I still am curious what urea nitrate would do if
used as the nitrate .
There is a related patent US1660651 and also US1691954 . |
I once had seen the chart but it was not annoted (just a .GIF file from a FTP) I think I see where you are going here. The idea of optimizing the
proportions and reaction times is exactly where I would like to take this. I know that you did some experiments within this issue before: I was hoping
might see my struggle and lend a hand...
Boomer: If you have anything at all I drink this stuff up. You know I print all this stuff out and fill a textbook with it for reading at lunch at my
work (no kidding). I choose this particular topic as it provides an inexpensive way to explore. You guys ALL did some stuff with this previously and I
apprieciate that it must be "old-hat" to you all. But to me it's new ground !
Once upon a time you guys all had a discussion as to the DDT phenomenon utilizing these very nitrations. And as it seems there are some very
significant patents dealing with safety concepts in mining. Some of the patents were listed under Nobel but I'll bet the original chemists were
contract people.
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Rosco Bodine
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The numbers for the H2SO4 scale should
wrap around the upper left corner of the trapezoid descending to zero at the upper right corner of the trapezoid .
When you choose a point somewhere in the field on the graph , it is the vertex of three rays oriented like a " Y " which has been rotated 90
degrees counter -clockwise . This graph is similar to but
oriented differently from some of the other nitration graphs which Urbanski has used , and it can be confusing until you plot a few graphs on it . The
horizontal lines are all only water content , and the left to right ascending sloped lines are HNO3 content , while the descending left to right
sloped lines are H2SO4 content .
It is true that at the lower temperatures which are required for the stability of the nitroesters that the production of nascent nitric acid from a
nitrate is greatly slowed and this makes the nitration proceed slowly , four hours or more for PETN at
room temperature with excellent stirring .
And the viscosity does increase with time
to a point where the mixture sets up solid
even using NH4NO3 , for the lower water content mixtures . My experiments were
moving towards use of greater amounts of acid / nitrate nitration mixture having higher amounts of water in relation to the polyol sulfoester in
order to have a more freely stirring mixture , as viscosity is the biggest problem to be overcome .
One strategy I was considering is to
first dissolve the polyol in sulfuric acid to form a liquid solution of the sulfoester ,
and pre-mix a good portion or all of the nitrate with a separate portion of acid which would be stirred as the liquid sulfoester is gradually added .
There
can be different strategies devised for
keeping the composition of the nitration mixture within the parameters defined by the nitration graph , but it is a matter of guesswork when a solid
nitrate is being used . There are mixtures which can keep the water content constant and remove its effect as one variable , and
this may be important in devising mixtures which behave predictably over the entire course of the nitration .
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quicksilver
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| Quote: | Originally posted by Rosco Bodine
One strategy I was considering is to
first dissolve the polyol in sulfuric acid to form a liquid solution of the sulfoester ,
and pre-mix a good portion or all of the nitrate with a separate portion of acid which would be stirred as the liquid sulfoester is gradually added .
There
can be different strategies devised for
keeping the composition of the nitration mixture within the parameters defined by the nitration graph , but it is a matter of guesswork when a solid
nitrate is being used . There are mixtures which can keep the water content constant and remove its effect as one variable , and
this may be important in devising mixtures which behave predictably over the entire course of the nitration . |
You might have seen this before (patent) but it moves exactly in that direction.
As an aside, I realize that for the most part that the metalic nitrates are generally utilized successfully in mixed nitration and ammonium nitrate is
used well in distilltions but it seems that ammonium nitrate mixes well at lower temps...what's been your experience with Calcium Nitrate? Some
months back you were involved in a discussion with others re; solid nitrates utilized in nitrations of mixed acids and someone mentioned Calcium
Nitrate.....has this been used with success? NaNO3 just doesn't mix at cooler temps like the ammonium salt which now appears to hold such
promise. CaNO3 is really cheap as it's used as a fertilizer as well....thought I'd ask.....
Your explanation was a good one by the way. The plotting of the "Y" in the graph was something I personnaly haven't seen before.
Attachment: hexanitrate.pdf (169kB)
This file has been downloaded 858 times
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Rosco Bodine
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There is a hybrid nitration method for PETN which I have considered as being worth experimentation , and probably worthwhile for other nitroesters as
well .
The idea is to first perform the nitration using straight HNO3 into which is sprinkled the granular polyol and after the straight HNO3 nitration is
completed ,
instead of drowning the mixture and losing the unused excess of HNO3 the spent mixture contains , a second nitration stage is effected by running in a
sulfuric acid solution of additional polyol as its sulfoester . This strategy could
increase the usual yield because of the
utilization of the HNO3 which would otherwise be lost , and the sulfuric acid
being added would also tend to cause precipitation of nitrated polyols like ETN
which otherwise remain dissolved in straight nitric acid nitration mixtures and
produce low yields . It is possible that
some yet further yield could be gotten from the addition of NH4NO3 or other nitrate to the nitration mixture . The best yields for certain polyols
might indeed be obtained no other way than by such a combined method .
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quicksilver
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| Quote: | Originally posted by Rosco Bodine
The best yields for certain polyols might indeed be obtained no other way than by such a combined method . |
Frankly, this is something I came close to quite by accident..
While using a nitration of solid nitrates, I found that the slurry became much too thick to pour. I added some HNO3 (the concept in reverse, as it
where). - I did not document yield weight but it appeared to be positive (about 5-15% greater). Now what I used here was was 70%....are you speaking
of distilled acid as a starting point or 70% ? I would seem that to make full use of the principal a strong acid would be the way to go but then - the
economy element takes a back-seat......
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Rosco Bodine
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There were several strategies which I thought about in terms of increasing the yield from a particular batch , if not limited to using one dedicated
method for the entire nitration . IIRC the simplest hybrid method would be to use 97% HNO3 and add polyol until the byproduct water formed during
nitration has lowered the acid concentration to about 77% . On the nitration graph the reaction points describing the course of the reaction would
rise as if climbing the slope of the right hand side of the trapezoid . When the mixture would ordinarily be spent , it
still contains unreacted HNO3 , but the nitration ceases in the absence of H2SO4 ,
so that deficiency is addressed by beginning to run in H2SO4 , and also continuing to add more polyol , in a simultaneous or alternating addition
scheme which maintains the water content constant , but with a gradually rising H2SO4 content and gradually decreasing HNO3 content as it is consumed
by the continuing nitration .
The points describing the reaction on the graph would make a left turn across the graph and trace a horizontal line towards
the left , with the reaction continuing until the HNO3 content depleted to a level where nitration ceased . If some NH4NO3
was also present in the mixture it would delay the time when the HNO3 was spent , because the formation of nascent HNO3 by reaction with some of the
sulfuric acid would also contribute to the nitration . This NH4NO3 could possibly be mixed with the straight HNO3 at the beginning , or mixed dry
with all of the polyol , or with just that portion of the polyol added after the H2SO4 addition was begun . It may be possible to dissolve the polyol
portion to be added concurrently with the H2SO4 in the H2SO4 , which will convert it to the sulfoester which can be then nitrated by the mixture , but
this strategy may not work as well if the composition of the nitration mixture is more favorable for direct nitration of the free polyol . Personally
I would trust the graph and then work out the plot points for the intended reactions , and compare them before making a choice on which strategy would
seem most likely to succeed .
This is one of many experiments which I have contemplated , but haven't had time to investigate . So anybody feel free to test any of my
untested ideas including this one .
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quicksilver
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| Quote: | Originally posted by Rosco Bodine
There were several strategies which I thought about in terms of increasing the yield from a particular batch , if not limited to using one dedicated
method for the entire nitration . IIRC the simplest hybrid method would be to use 97% HNO3 and add polyol until the byproduct water formed during
nitration has lowered the acid concentration to about 77% . On the nitration graph the reaction points describing the course of the reaction would
rise as if climbing the slope of the right hand side of the trapezoid . When the mixture would ordinarily be spent , it
still contains unreacted HNO3 , but the nitration ceases in the absence of H2SO4 ,
so that deficiency is addressed by beginning to run in H2SO4 , and also continuing to add more polyol , in a simultaneous or alternating addition
scheme which maintains the water content constant , but with a gradually rising H2SO4 content and gradually decreasing HNO3 content as it is consumed
by the continuing nitration .
This is one of many experiments which I have contemplated , but haven't had time to investigate . So anybody feel free to test any of my untested
ideas including this one . |
Well, I wanted to go for it. I had some time and here is some notes from one that included some elements you had discussed & patent concepts....I
was quite happy with the results...
Mannitol Hexanitrate NOTES: 12/4/05
20 grams of mannitol was ground very fine (beyond any crystaline make-up via ball mill).
This was mixed into 130gr (72ml @ 93%) H2SO4 @ 20 C via magnetic stirrer until completely in solution. Material was stirred until transparent. Care
was taken to prevent carbonization.
The Mannitol-H2SO4 solution was then placed into a refrigerator to maintain temp of 15 C.
A solid nitrate (KNO3) was mixed with H2SO4 in a seperate beaker: 60gr KNO3 into 182 gr (100ml) H2SO4. This was prepaired at 60C and stirred until
clear solution was acheived. This solution of mixed acids was then placed in a refrigerator and both solutions brought to 15 C.
The mixed acid solution was placed on a magnetic stirring device and into it was introduced the mannitol / H2SO4 solution in small portions (dropwise,
3 drops per second).
The temp of 0-15 C was maintained for this addition & was achieved by using an ice and ethelene glycol ("anti-freeze") bath. During the addition
the mixture became quite thick.
At that junture 50 ml of 70% HNO3 was added in two portions. The HNO3 being previously chilled to 15 C having been in a refrigerated environment. The
solution continued to thicken and was withdrawn from the ice bath and stirring (total time 60 min, stirring) and placed covered in refrigerator.
Allowed solution to remain in refrigerator at 15 C. After 2 hours solution solidified and appeared to have no mobility but appeared as a solid. Total
time until initial water wash; 5 hours.
Random observations: After addition of mannitol / H2SO4 there appeared to be particulate matter forming in solution VERY quickly and would stick to
side of beaker when tipped. At no time did solution appear clear. As soon as mannitiol was introduced into mixed acids there appeared to be
particulate matter in solution. Therefore I believe that the initial nitration was working fine. The 2nd addition of liquid HNO3 I believe got me a
deceint yield from BOTH the increased nitration and the mobility to stir even further. Consistent stirring appears to be a key factor in higher yield
and to maintain safety. Hot-spots cannot develop if stirring is maintained. Temp is controled more effectivly.
Yield: Dealing with totally dry and re-crystalized material starting with 20 grams of mannitol was 18.8 gramn MHN. Thus aprox .9 grams was produced
from one gram of mannitol. Numerically I came out with a 60% - 65% yield on paper but in the beaker I would put it lower. Deceptivly large apppearing
yield at first.
Opinion: Not all that bad if one considers that we are not dealing with distilled acid and I believe that it COULD be improved upon with a higher
quanitity of HNO3 or differing solid nitrate. I believe that my ratios are correct at this time. The target was to get to a high yield as 1 gram
mannitol to 2 grams MHN....I believe that this may be possable with refinment. Or at least 1: 1.5 (after recrystalization and totally dry). This is an
addendum to the initial method at which time I believe that on paper 50ml of 70% HNO3 is the appropriate weight but now I believe that twice that
could be used if the time factor increased as well. Yield would be much higher!
Didn't have a chance to do any pictures of the "before & after" re-crystalization & that's sort of a shame as the initial result _looked_ like
twice what one would expect. Results were from desicator and re-crystalization.
[Edited on 5-12-2005 by quicksilver]
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Rosco Bodine
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When you do the neutralization and recrystallization ,
it would be good to try betaine as a stabilizer .
You can do this by adding some betaine to the
alcohol solution after it has been just neutralized with
a little ammonia or urea , and also dissolve some
betaine in the water which will be dripped slowly
into the stirred warm alcohol solution of MHN ,
so that the MHN crystallizes out in the presence of
and entrapping small amounts of betaine as an
impurity . 1 or 2% levels in the solutions should be
plenty . The storage and heat stability of the MHN
crystals should be greatly increased by this treatment .
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quicksilver
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| Quote: | Originally posted by Rosco Bodine
When you do the neutralization and recrystallization ,
it would be good to try betaine as a stabilizer .
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There is an opportunity to use this concept as you had suggested and I think I also have a better ratio. But I have learned to not weigh until the Fat
Lady Sings. I may have just found the best yield ratio....
I hadn't realized how much little neuances influence nitrations. The things that some often rush through without thinking like particle size and time
in different stages of nitration. I have a lot more in my notes that upon reflection, I should have included. In hindsight I believe that these things
can make a real differnce.
Would you know an OTC source for Betaine? I have been using Diphenylamine in ratio of 2% by weight of total dry product prior to re-crystalization.
--- Thanks again: I wish there were more INEXPENSIVE ways to experiment with aspects of this broad subject (energetic materials, etc)..... an OTC
source for Betaine would further that issue 
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Rosco Bodine
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Betaine powder is a nutritional supplement ,
one of the B vitamins IIRC , and is sold as
freeform betaine powder or TMG ( trimethylglycine ) .
There is a separate thread on betaine . It
is sold by the usual health food vendors .
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