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entropy51
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Quote: Originally posted by Sakamura  | I did not think I would get this type of response! Yes I assure you I am a Dr trained in the UK. We never make solutions everything is pre packed and
pre measured. ..... You seem to have a distorted Idea of what a modern Dr's job entails. Even the Formaldehyde solutions used in specimen fixation in
histopathology were pre made.
No my questions have not been answered already as it is mainly about Ferro not ferri.
A molecular and cellar biology or pathology lab is completely different to a physical chemistry lab. I am comfortable in the former but not in the
later (sorry for that misunderstanding), so as far as physical chemistry goes I am a beginner.
My Bio is not mixed up - actually it's pretty standard. Med school ->intercalated BSc ->Finish med School and do the jobs best suited to your
ultimate speciality.....
I really thought this board was going to be helpful - obviously I was mistaken and apparently I am not welcome. Oh well Chemistry is not the only
thing I am interested in so I will probably abandon the whole thing and move on to another field - which is a pity. At least the government will be
pleased there will be one less amateur chemist.
All the best and no hard feelings.
[Edited on 23-9-2009 by Sakamura] |
Sakamura, I am an M.D. trained in the U.S. and I agree that we don't normally have to make dilutions.
However, part of that training was in general, organic and biochemistry. We spent much time in the labs and we had to learn how to calculate
stoichiometry and perform dilutions.
I have also worked in, and supervised, cellular biology labs. Calculating and performing dilutions was something we did for every experiment because
solutions had to be accurately made up. Except for very basic reagents and culture media nothing that we used was available pre-packaged.
I'm sorry that you feel put off because your request was met with skepticism, but had you made yourself known to us before asking about KCN the
response would have been different.
Ferricyanide is mentioned in this thread.
Books in the forum library and elsewhere on the web would answer most or all of your questions. The fact that you would give up your newfound hobby
because of a single encounter with this forum makes me doubt your seriousness.
If you are really interested in chemistry then stick around and participate in our discussions. Much is to be learned here, and even more so in our
library.
If your chemical skills are rusty you absolutely should not practice them by preparing HCN.
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chloric1
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Agreed. Even in the "good 'ol" days of the 1920's and 30's, most introductory labratory manuals would start you off slow and work up your skills to
handle the specially deadly proceedures like cyanide, bromine, HF, and others. We at sciencemadness follow loosely this same approach. Learn
manipulations while working with the more benign substances first. Heck you can fill an afternoon playing around with sodium silicate and/or
borate Personally, I have chosen not to mess with cyanides because I don't
feel I have enough safety gear. I feel confident in handling the glassware and equipment but I need to implement a series of safety measured before I
can even consider HCN preparation.
Fellow molecular manipulator
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entropy51
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Hydrocyanic Acid Reference
I have posted a reference on production of HCN from ferrocyanides and ferricyanides in the currently active References Wanted thread in the References
section of the forum.
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Sakamura
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Thank you entropy51. Training for a MBBS in the UK or an MD in the USA is obviously very different. I asked a few colleagues if they can do the
stoichiometry calculations required accurately and the answer was universally well theoretically yes but I have never done it, why don't you ask a
chemist to do it? They do it all the time. I.e. they to would want a check as well, have never done it and are non too confident of their ability to
get it right first time. But it does not matter - you are the experts not me, so I will take your advise and put this project on indefinite hold and
do much more reading before I attempt anything and it won't be anything as hazardous as KCN .
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densest
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@sakamura - wise to keep cyanides on hold. The great hazard of -CN as with H2S is that it paralyzes respiration very very quickly. H2S is actually
more toxic (?10X?) and more common but the smell keeps people from getting killed. Still, some large alga blooms on French beaches this year have
killed at least one person and a horse due to H2S emitted during decomposition. Either one can be detoxified if in small enough quantities - emphasis
small.
I've worked with cyanides and many other highly toxic materials and am still around to write. Some of it was dumb luck. Most of it was reading what
the conditions necessary for toxicity (amounts, pH, compounds, etc.) and a very clear idea of how many little droplets and particles drift from the
equipment despite my most careful efforts. You can get away working with almost anything inorganic chemical at 1 - 10mg quantities (with some glaring
exceptions) - it's an interesting art getting useful data at that level. A draft away from you into an activated charcoal filter (replaced frequently)
can be a lifesaver, along with a big dishpan full of water into which to drop any test-tube which might have a reaction getting out of control. Small
test tubes! Disposing of the water later might be a problem. It's a much better problem than going to hospital or the morgue.
Good luck and enjoy your experiments!
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Sakamura
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Well you have me convinced
densest I hate to criticize fellow Dr's but the recent change in training has made things worse not better. I doubt an FP1 or 2 who will try to treat
you first at secondary care level even knows about the electron transport chain. If I did it (and now I am not about to) I think if anything went
wrong it would be an autopsy job - I have done enough of those and it actually horrifies me.
I had a chat with my old chemistry Master a PHD Chemistry (organic I think) and he agrees with you guy's. This stuff is way too toxic but he was
very enthusiastic about teaching and I never had a boring lesson from him. He offered to get me to a safe level using his own lab on weekends but
quite justifiably still does not recommend making KCN (although he admits he has done it multiple times himself). All I need to do is pay for the
reagents and disposables (gloves etc and glassware that's not to hand) so I still have a chance to drink deep of the Pierian spring without killing
myself. This is perfect for me i.e learning under the supervision of an expert instead of 'having a go' and praying.
Thanks for all your advice.
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chloric1
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That is GREAT news. A REAL lab for you to practice in. I am really happy for you. I have a burning urge to ask what you want cyanide for? Making
complexes, electroplating silver? As far as the complexes or organic synthesis you would have to wait. But for silver plating there are thiosulfate
and iodide baths. I hear these are more expensive and more difficult to operate.
Fellow molecular manipulator
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entropy51
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| Quote: Originally posted by Sakamura | This is perfect for me i.e learning under the supervision of an expert instead of 'having a go' and praying.
Thanks for all your advice. |
And you thought we weren't being helpful.
I told you should stick around. Mostly we are not a bad lot.
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Sakamura
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Again thanks for all your advice. I am pretty chuffed now having access to a Physical chemistry lab with some one that knows what they are doing as
well as an organic lab. The only downer is that I know he will give me massive amounts of homework to do (or he did when I was at School) which is
what is required but I doubt I will feel that way after a long day at work! So I may well be back for help on answering his questions which are never
simple.
You all want to know what I want(ed) it for. Well I will give a very short over simplified explanation as it's a cyanide thread and my ultimate aim
does not have much to do with cyanides. After I had got comfortable with working with them electroplating etc anything to get me back working
comfortably in a Physical Chemistry environment - which is usually fascinating and I am sure I would have lots of fun on the way, all the more so if
the thing was not so toxic. I probably overemphasized this in my previous posts. Ultimately (and this would take years including ethics comity
approval and probably a grant) I intended to make a tissue stain that differentiates two cell types that wrap up neurons (nerve fibres) Schwann cells
for the peripheral nervous system (PNS) and Glial cells for the central nervous system (CNS) without Immunofluorescence which is not cheap, doesn't
last and is generally hard to work with, especially if you are double or triple staining. No stain is currently available 'off the self' that will
differentiate between them but it can be made and it's main ingredient is KCN - buying it is an option if the lab has a licence, I don't know if it
has, but I would be dubious of the purity and learn virtually nothing about chemistry. I did my BSc thesis in nerve regeneration (for the non medics
the CNS does not regenerate - think superman dying paralysed, where as the PNS 'has a go' then gives up). I do not have the reference to hand but an
Athens search of 'Schwann cell depots in frozen skeletal muscle grafts' will find it. I got PNS nerves with some encouragement to fully regenerate
over a 4 cm gap in 3 weeks (although it isn't perfect for esoteric reasons it has been adopted in clinical practice). There are glaring holes in our
understanding of nerve regeneration e.g 'why does nerve 1 the olfactory nerve (the one you smell with) regenerate fully with no help when no other
nerve does?' I think I know why but I have to prove it. Hence my interest in pure KCN. I just wanted to make a stain, further my understanding of
Physical Chemistry, have some fun along the way and hopefully do some good in the process - I realise now I should have explained this from the
beginning but I got carried away with the idea. Again thanks for all your advice.
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watson.fawkes
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| Quote: Originally posted by Sakamura | | I intended to make a tissue stain that differentiates two cell types that wrap up neurons (nerve fibres) Schwann cells for the peripheral nervous
system (PNS) and Glial cells for the central nervous system (CNS) without Immunofluorescence which is not cheap, doesn't last and is generally hard to
work with, especially if you are double or triple staining. No stain is currently available 'off the self' that will differentiate between them but it
can be made and it's main ingredient is KCN |
Not to pry too much, but is the cyanide differentiation between
these two cell types related to some function over and above myelination that one cell type has and the other does not?
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Taoiseach
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This is from "the industry of cyan compounds":
Ammonium cyanide, NH4CN, is a highly volatile flammable crystalline solid that smells like both NH3 and HCN at the same time. Boiling point is 36°C.
It is highly soluble in water and ethanol and extremely toxic. Decomposes slowly at RT. It had some applications in industry because it is easily
formed by leading dry NH3 over glowing charcoal. The NH4CN was then used to prepare KCN.
Synthesis of NH4CN: Mix 3 parts of potassium ferrocyanide and 2 parts NH4Cl and destill @100°C.
The vapours can be condensed to solid NH4CN.
Also, destillation of 3 parts potassium ferrocyanide, 2 parts NH4Cl and 10 parts water yields a dilute solution of NH4CN.
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JohnWW
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| Quote: Originally posted by Taoiseach | This is from "the industry of cyan compounds":
Ammonium cyanide, NH4CN, is a highly volatile flammable crystalline solid that smells like both NH3 and HCN at the same time. Boiling point is 36°C.
It is highly soluble in water and ethanol and extremely toxic. Decomposes slowly at RT. It had some applications in industry because it is easily
formed by leading dry NH3 over glowing charcoal. The NH4CN was then used to prepare KCN.(cut) |
That method of synthesis, involving partial decomposition of NH3 under high heat over charcoal (presumably in the absence of air), is most unlikely to
produce anything like pure NH4CN, and there would have to be some sort of purification. I am fairly sure that other volatile cyano-compounds like
cyanamide, NH2CN (especially), HCN, (CN)2, HN=C(NH2)2, HN=C=NH, and possibly H2C=NH and HN=CH(NH2), would also be produced in significant to
substantial quantities.
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watson.fawkes
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Would you provide a complete reference for this? I can't even
find the title or any reasonable variants. Is it a chapter title in some other work?
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Taoiseach
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Yes don't even think about it, all sorts of crap would be in the destillate. This method is completely useless. There's more convenient routes to
impure cyanide, most of which have been discussed in this thread.
The interesting part is that ferrocyanide+NH4Cl yields vapours of PURE AMMONIUM CYANIDE at a temperature as ridiculously low as 100°C. Besides,
100°C is a temperature most easily maintained by use of a simple water bath 
Ammonium chloride sublimes at about 300°C so it should not contaminate the end product. What we have here is a method that rips off CN- from
ferrocyanide and delivers it in a PURE form. The vapours can be condensed in a flask cooled in an ice bath and then reacted with KOH.
I hope the book doesnt bullshit us and this really works, because it sounds almost too good to be true!
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entropy51
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The reference may be "The cyanide industry: theoretically and practically considered "
which is available as pdf on books.google.com
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Taoiseach
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Its a German book and available online:
http://www.archive.org/details/dieindustrieder00khgoog
Dunno if theres an english translation tough.
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Taoiseach
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The preparation from ferrocyanide+salmiac is also mentioned on wikipedia:
http://en.wikipedia.org/wiki/Ammonium_cyanide
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S.C. Wack
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It's a big jump from
"Le cyanhydrate d'ammoniaque se prépare très facilement par double décomposition. Un mélange de 1 équivalent de sel ammoniac et de 1 équivalent
de cyanure de mercure desséché, entrent facilement en fusion à la flamme de la lampe à esprit-de-vin, et dégagent en abondance du cyanhydrate d
ammoniaque, tandis qu il reste dans la cornue du bichlorure de mercure. On réussit pareillement, et d une manière plus économique, en substituant
au cyanure de mercure le cyanure jaune de potassium et de fer effleuri."
http://books.google.com/books?id=c5s5AAAAcAAJ&pg=PA231
to
The research of Langlois, Kuhlmann, Bueb, Bergmann, Lance, Voerkelius, et al. with ammonia and carbon are known and available if you just search for
them. Had the board not deleted the Beilstein file that I uploaded to this thread earlier in this post [why bother uploading anything when my files keep getting deleted, even small ones disappear], you'd be able to see the citations.
Google to the rescue.
http://books.google.com/books?id=cR8SAAAAIAAJ&pg=PA40 (NH4CN)
http://books.google.com/books?id=cR8SAAAAIAAJ&pg=PA30 (NH3 + C)
The book mentioned by entropy51 is one of many books available on cyanides and their manufacture, it is a good one http://books.google.com/books?id=qE4wAAAAMAAJ
[Edited on 27-9-2009 by S.C. Wack]
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JohnWW
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The URLs for direct downloads of it, and full title, are:
http://ia310837.us.archive.org/2/items/dieindustrieder00khgo... 5.30 Mb or
http://ia310837.us.archive.org/2/items/dieindustrieder00khgo... 8.95 Mb
- Die Industrie Der Cyanverbindungen, Ihre Entwickelung Und Ihr Gegenwärtiger Stand - H Köhler (1914)
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Taoiseach
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Reduction of cyanate with C yields cyanide contaminated with carbonate. The books says that pure KCN can be obtained by leaching the fused mass with
hot anhydrous ethanol.
Right now this looks like the most promising route to me.
Also cyanate can be reduced quantitatively to cyanide with CO gas at red heat. This seems to work with sodium cyanate only:
1. Sodium cyanate from sodium carbonate and urea: Na2CO3 + 2CO(NH2)2 -----> 2NaOCN + 2NH3 + CO2 + H2O
2. Sodium cyanide from sodium cyanate and carbon monoxide:
2NaOCN + 2CO -----> 2NaCN + 2CO2
About 8grams of 100% formic acid would yield the stochiometric amount of CO to reduce 10,7g NaOCN to 8g NaCN, no losses considered.
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Taoiseach
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Anyone has reliable figures on KCN's solubility in hot ethanol?
All I could find is a vague remark in Vanino's handbook of preparative chemistry, saying its solubility in boiling alcohol is "65%".
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garage chemist
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Ullmanns Encyclopedia says 0,57g/100g in 100% Ethanol at 19,5°C, and 4,91g/100g in Methanol at the same temperature. No other temperatures are given.
I've used Methanol with a Soxhlet extractor to extract KCN from the powdered residue of K4Fe(CN)6 fusion, and the residue from evaporating the MeOH on
a boiling water bath in vacuum came out as 85% KCN upon titration with 0,1M AgNO3.
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Jor
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Interesting. You just heated ferrocyanide in a crucible? Is porcelain suitable? Ofcourse the product must be protected from moisture and oxygen, but
that is not a problem, I will just cover the porcelain crucible with a porcelain plate. What temperature is required? Is a propane torch suitable?
I don't have a Soxlet, but I guess boiling in methanol with vigorous stirring is sufficient.
Is evaporating without vaccuum also suitable? I don't see why not.
Now the only problem is, how to purify the 85% KCN...
What were your yields?
[Edited on 29-9-2009 by Jor]
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entropy51
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Yep. See this book for this and other ancient but low tech methods: http://books.google.com/books?id=qE4wAAAAMAAJ
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JohnWW
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Its title is: The Cyanide Industry: Theoretically and Practically Considered (1906)
Author: R. Robine, M . Lenglen, J. Arthur Le Clerc, Charles Edward Munroe
Publisher: J. Wiley & Sons, 1906
But the book cannot be downloaded from Google, except for a few snippets! Instead, you can download the whole book from this page:
http://www.archive.org/details/cyanideindustry01munrgoog
The actual URLs for downloading it are:
http://ia331411.us.archive.org/2/items/cyanideindustry01munr... 13.8 Mb or
http://ia331411.us.archive.org/2/items/cyanideindustry01munr... 20.4 Mb
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