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Pixicious
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It would be interesting to know how to make cyanohydrin.
If so that is a really interesting method because potash would be really easy for people to come by here.
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Pixicious
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13 is unlucky, 14 is nice.
I'm not sure if you mean ethanol or methanol with the formula you mentioned.
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Nicodem
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| Quote: | Originally posted by Pixicious
It would be interesting to know how to make cyanohydrin. |
Acetone cyanohydrin is made by the reversed reaction (the reaction is catalysed by traces of KCN or any other base):
HCN + CH<sub>3</sub>COCH<sub>3</sub> ---> (CH<sub>3</sub> <sub>2</sub>C(OH)CN
I'm quite sure you can find the exact experimental in Vogel's, Organikum or any other book on laboratory practice.
PS: Try not to double post. Use the edit function instead.
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grind
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The way via the cyanohydrine only makes sense, when you can buy the cyanohydrine. It´s cheap but very toxic and I think for most people hard to get.
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Pixicious
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| Quote: |
1) Where can we get strong ammonia solution
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You mix NH4Cl (Ammonium Chloride) in water, this is not exothermic and then add NaOH (Sodium Hydroxide), this is exothermic.
If in the right quantites you will produce salt so there is no need to worry when you wash the solution away. The gas given off is NH3, feed this
through water and you have a very concentrated NH4 solution.
NH4Cl + NaOH + H2O -> NH3 + 2H20 + NaCl
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quicksilver
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| Quote: | Originally posted by amchem2000
1) Where can we get strong ammonia solution |
For absolute lowest cost I like ammonium sulfate (available at any garden supply, hardware store and sodium hydroxide (lye) via the above mechanism of
gas generation through water. In terms of cost for either anhydrous ammonia gas or ammonia solution, you are actually dealing with pennies.
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497
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I have a solution of an unknown amount of sodium cyanide with quite a bit of sodium carbonate and probably some sodium cyanate along with. I had the
idea to add calcium hydroxide forming calcium carbonate precipitate. This should also produce calcium cyanide right? Then I read that calcium cyanide
is unstable in water, so would I just get a bunch of HCN or what? There must be a better way to separate them.
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Pixicious
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497: I don't know.
I just came here because from things I have been reading there is another way of producing NaCN from just household.
This method relies on Ammonia, Chloroform and Sodium Hydroxide producing Sodium Cyanide.
A couple of questions arrise. How are the three mixed together? NaOH + NH3(aq) cannot be in the same solution together, NaOH + CHCl3 -> NaCl + H2O
+ CCl3 and, NH3(aq) + CHCl3 is the only method I can think of mixing the two before dripping in the Sodium Hydroxide. Although I have a memory which
says this produces HCN.
Is the reaction of Chloroform and Ammonia exothermic? If so is HCN, HCl or both released as a gas, or do either or both remain a liquid? I think this
is an essential question for anybody here. Especially for purification.
The method involves just Ammonia, which is obtained by concentrating Ammonia solutions through heat into a much smaller amount of water. Calcium
Carbonate which is used to produce Calcium Hydroxide, Sodium Hydroxide and Acetone. Also needed is Acetic Acid and Sodium Hypochlorite.
Obviously you will need to distill and dry at several points, and I am not sure where you can produce drying stuff from household. (Maximum temperture
needed is: 850oC and that is only to produce Sodium Hydroxide.)
I would like to know if there is a known method of reacting Sodium Hypochlorite to form Calcium Hypochlorite power.
The seperation as described of HCl and HCN and an excess of NH3. (Just so all the chloroform has reacted) is to bring it to a boil of 26.5oC and bring
a controlled release of HCN gas insealed containers feeding into a NaOH and methanol solution? Or in this case would the Hydrochloric acid not bound
with the Hydrogen Cyanide and will be released as gas just leaving pure Hydrogen Cyanide..
[Edited on 9-4-2008 by Pixicious]
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Pixicious
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If you bubble Ammonia through a solution of Hydrogen Cyanide and Hydrochloric Acid, would the Hydrochloric Acid (assuming it remains a solution in
HCN) react to form Ammonium Chloride?
Then would it just be a simple case to filter the Ammonium Chloride from Hydrogen Cyanide to obtain a pure form of Hydrogen Cyanide.
Something I've been wanting to pick with you for a long time Polverone. If to achieve HCN all you have to do is slightly warm acidified Potassium
Ferrocyanide, why is it not considered poisonious to ingest?
[Edited on 10-4-2008 by Pixicious]
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Sauron
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Acetone cyanohydrin is easy. Yes the prep is in Vogel; he cadged it from Org.Syn as usual. See it there for more details and a larger scale.
I tried to order some from Aldrich and they wanted something like $2000 for ocean freight hazmat. So I got it from Merck. No hazmat which is entirely
America shooting itself in the foot.
I use it in one of the processes to prepare AIBN, the radical initiator for polymerizations and some chlorinations. Could have made my own but that
would have meant making anhydrous HCN and better to work around that, than to work around it, if you get my meaning.
Sic gorgeamus a los subjectatus nunc.
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497
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I have heard mention of fusing calcium cyanamide with Na/KCO3 to yield the respective cyanide along with CaO and oxygen. If you can get/make CaCN2
easily this might be useful. Sorry I don't have more details, I'm way too busy with school to work on this.
And sorry if this is old news, its been a while since I read this thread in detail.
[Edited on 8-5-2008 by 497]
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Axt
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NaCN via Nitrite + Acetate
CH3COONa + NaNO2 --> [ONCH2COONa] --> NaCN + NaHCO3 + H2O
See the attachment, in german so I cant make a lot of it out, would be good if someone can confirm what I've written here.
By heating a mixture of 12g sodium acetate with 10g sodium nitrite with added bicarbonate (to stop or at least control the deflagration of the
mixture) it gives NaCN in 25% yield. This isn't a lot, ~1.8g per 10g of nitrite. Gasseous HCN and H2O are released during the reaction.
K nitrate + K acetate also forms some cyanide, presumably through the nitrite intermediate.
Is the extraction of ther NaCN mentioned in the article? How was it analysed to determine 25%? It says something about 70% alcohol but I cant make it
out.
Maybe its possible to increase the yield by trapping the lost HCN via NaOH/EtOH, though I suspect this will also have a bicarbonate impurity.
Attachment: nitrite-cyanide ocr.pdf (97kB)
This file has been downloaded 1295 times
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Formatik
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In this process without the soda they had a violent explosion from it (I'm not sure what the source of explosion is, if it is the possible reaction as
an oxidizer mixture or HCN as according to Urbanski hydrogen cyanide is explosive, and alkalinity can polymerize it explosively). The procedure they
give they say it occurs without explosion. The proportion of soda needs to be as described, already 3g of mixture and 2 g soda ratio deflagrates
pretty vigorously. Though a 1:1 mass ratio in a metal bath starts to soften and inflate around 300 deg., at 375 deg. water and significant amounts of
HCN is let free under fizzling and freezes to a porous mixture of carbonic acid salt and NaCN.
12 g sodium acetate and 10 g NaNO2 with 22 g soda (Na2CO3) in a porcellain crucible is heated over a free flame. This will soften and glow, as soon as
the reaction temperature is reached, there is a lively glimmering, but it occurs without explosion or spattering, whereas water and noticeable amounts
of hydrogen cyanide escape. The porous, crumbling mass is colored dark from the separated coal. By boiling with 70% pure alcohol the NaCN can be
extracted and then after a repeated recrystallization by cooling an aqueous-alcoholic solution, can the plates as described by Joannis be obtained.
They did the determination of yield by precipitating AgCN from the NaCN, and then weighed it. The yield of NaCN is dependent on the type of heating,
and from that no more than 25% yield results.
Note: NaHCO3 will lose mass (37% mass) as it is heated at low to moderate temperatures forming H2O and CO2. Na2CO3 forms several hydrates and will
also lose mass. Both of these might skew the ratio unfavorably. Also reading further the explosion source is likley a redox reaction maybe going
through unstable intermediates, as NaNO2 reacts similarily with sodium formate, propionate, or tartrate, also forming more or less NaCN.
[Edited on 7-6-2008 by Schockwave]
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Ephoton
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an idea 
if one was to go from sodium or potassium cyanate then
any reducing agent that works in the conversion of nitrates
too nitrites should work.
there was a post in this forum some were from a gentleman
from the upper block of europe stating it was impossible to
get nitrites in his area. he stated that the general way to
obtain these was to heat the nitrate untill it was molten then
add lead tartrate.
after a bit of thought and some looking around and a few small
tests this would seem to me to be the best way to make
very pure cyanide as well.
I would expect any problems found in the conversion of one
would also be seen in the conversion of the other (ie nitrate
or cyanate)
by the way thanx KMnO4 for the hint it was a true killer
just as I thought to be honest it will stay at the amide.
and thanx Nicodem for posting the entire article.
[Edited on 9-6-2008 by Ephoton]
e3500 console login: root
bash-2.05#
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Axt
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Thanks for the translation Schockwave, this may be the explanation for its explosive nature.
The double salt, KCN.KNO2.H2O, is obtained by dissolving potassium nitrite (50 grams) aiid potassium cyanide (20 grams) in the smallest possible
quantity of water and allowing the solution to evaporate over sulphuric acid. Potassium cyanide separates first, and then the new double salt in
short, characteristic prisms. It explodes with a loud report when heated at 400-500°. J. Chem. Soc., Abstr. 70, I, 69 1896.
[Edited on 14-6-2008 by Axt]
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jarynth
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Cyanide manufacture
Gary R. Maxwell's Synthetic Nitrogen Products (Kluwer) offers a quick survey of the industrial syntheses of basic nitrogen compounds.
Chapter 19 is dedicated to hydrogen cyanide.
I won't even mention the high pressure gas phase processes, but the following could be useful in an amateur setting, provided the necessary precaution
is met.
1) 'The dehydration of formamide is conducted in iron catalyst at 380°C to 430°C under reduced pressure. The tubes are filed with Fe or Al
phosphate catalyst that also contains Mg, Ca, Zn or Mn as promoters. The selectivity to HCN is 92% to 95%'
(Weissermehl, Arpe Industrial organic chemistry VCH 1997)
2) It's a common oppinion that this organic compound cannot be turned appreciably into ionic cyanides; luckily this is true as far as the human
metabolism goes, but the Japanese patent 10167721 makes a refreshing claim. For those who can find acetonitrile cheaply, and with a tube furnace,
consider this:
'PROBLEM TO BE SOLVED: To efficiently convert acetonitrile into prussic acid by a simple method by using activated carbon as a catalyst in producing
prussic acid by reacting acetonitrile with oxygen or oxygen and ammonia. SOLUTION: In this method for producing prussic acid by effectively utilizing
acetonitrile as a by-product in production of acrylonitrile, activated carbon is used as a catalyst. Industrially useful activated carbon is generally
used. The shape of activated carbon may be granule of powder. Pure acetonitrile is not necessarily required and a mixture may be used. Oxygen may be
diluted with an inert gas such as nitrogen or may be supplied as air. The amount of oxygen used is preferably 2-3 mols based on 1mol of acetonitrile.
The reaction temperature is preferably 400-500 deg.C. The reaction pressure is preferably high with respect to contact efficiency with the catalyst
and may be normal pressure or slightly under pressure in terms of simplicity of facilities. The reaction time is preferably about 0.5-5 seconds.'
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len2
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Someone on the forum was interested in this so I tried it out.
| Quote: |
Decomposition of Potassium Ferricyanide by the Action of Heat. V. CUTTICA (Guzsetta, 1922, 52, i, 20-.25).-
Protracted heating of potassium ferricyanide at 230C results in complete decomposition of the salt according to the equation
2K3Fe(CN)6 = 2FeC2 + 2N2 + CN2 + 6KCN.
658 56 52 390
The intermediate green substance formed during the heating (cf. Locke and Edwards, A., 1899, i, 407, 557; Cuttica and Canneri, A., 1921, i, 322)
exhibits the oxidising properties of the original salt, but differs from it in certain of its reactions, and contains complex iron cyanides with less
than six cyanogen groups in the molecule.
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Ferricyanide is superior to the ferro salt in that there is no water of crystalization (.3H2O for ferro) to speak off. But at 230C there was almost
no weight loss as per formula - and there was only 0.1gms lost at 480C for up to two hours heating. This puts in doubt the report above if it refers
to anything like reasonable reaction time, as chemical reaction rates on average double every 10C or so. Nonetheless some iron was reduced as
addition of HCl resulted in deep blue colouration indicating some Fe(II) present (the original ferricyanide gives a deep yellow colouration only).
4.4gms ferricyanide was then held at 180C for 1hr in a box oven to rid of any moisture, then heat was raised to 400C for 0.5hrs, 640C 2hrs, 680C
0.5hr. A borosilicate tube blocked with glass wool was used as container - which was not ideal as it softened and bent, while KCN being basic attacks
the glass. Nonetheless at the end the bent tube was filled with a white powder and black granules, was brocken, ground up, and 50ml H2O added and
mixed. Filtration under vacuum gave a clear solution (no ferri evident in product). This shouldnt be evaporated as KCN decomposes in boiling water.
Alcohol added (100ml) immediately gave a white precipitate which was filtered and dried. 1gm obtained, which = 40% yield - would be higher for larger
batches.
To test for KCNO 0.1gms was dissolved in H2O/alcohol and HCl (conc) added. A heavy mist of HCN resulted, but there was no effervescense (CO2) - this
quick test indicates no substantial oxidation of KCN had occurred.
[Edited on 22-2-2009 by len2]
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densest
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One approach which I saw appeared to work:
To a cold saturated solution of KOH was added K4Fe(CN)6 crystals until no more would dissolve. The flask was sealed with plastic film to exclude
CO2 and O2. Over a period of some days, Fe hydroxides and oxides precipitated, and the color of the solution changed from yellow-green to clear. The
supernatant was decanted. On further chilling, transparent square plates and small cubes crystallized. Filtered quickly, washed with a minimum of very
cold distilled water, a very small amount (milligrams) gave a very strong blue reaction with FeSO4 solution.
I believe it took several weeks overall, using an outdoor shed during autumn. It would seem to depend on KCN being somewhat less soluble than KOH or
K2CO3 and very little O2 being available to destroy the KCN. Perhaps the air in the flask could be displaced with something else to improve the yield.
According to an old Chem Rubber handbook, the only likely substance in that solution which crystallizes to a square or cubic form would be KCN giving
a second reason to believe the process worked.
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S.C. Wack
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I'm sure people will be giving that a try now.
----
There are many places where one can find a mini-review of cyanide, and many resources have been posted on this board over the years. At the very
beginning, Beilstein mentions a review in JACS
http://books.google.com/books?id=lAkSAAAAIAAJ&pg=PA31
there is also
http://books.google.com/books?id=lAkSAAAAIAAJ&pg=PA3
These are not the greatest, but they are informative to those not aware of the history (to 1889) and it gives me something to post.
If anyone is interested in looking up old things probably in a different language, since I have these old photocopies and they're just gathering dust
and personally I like it when people post things such as Beilstein, 14 pages from the Hauptwerk on preparation/formation/occurrence of HCN, the
complete entries for NH4CN, NaCN, K4Fe(CN)6, K3Fe(CN)6, and most of KCN.
Attachment: beilstein_cn.pdf (1.7MB)
This file has been downloaded 2000 times
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len1
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Thanks for the info SC Wack. But none of the links work. The first two only give me the title pages the last hangs the computer.
ANYONE WHO WORKS WITH CYANIDES INCLUDING MYSELF MUST WEAR A GAS MASK, GLOVES and GLASSES!. Even in this case when theoretically no HCN is generated
KCN spilled on a stray drop of HCl, can generate enough HCN to kill, especially if you are like myself and cant smell it. Grinding or picking KCN can
stray particles into your face and mouth - also enough to kill. A mask will guard against all of this. Gloves give protection against KCN dissolving
in skin moisture and penetrating though cuts etc. Glasses protect against KCN particles flicked into the eye dissolving in tears, being absorbed, and
killing. Symptoms of mild CN poisoning resemble symptoms of fear of having been poisoned (anxiety).
Ive done the Ksp calculations, and the KOH method must work and it must work even better with K3FeCN6 since its last cyanide is weakly bound (making
it poisnous) so that it can be substantially separated even in boiling water
[Fe(CN)6]3- + OH- -> [Fe(CN)5OH]3- + CN-; [Fe(CN)6]3- + H2O -> [Fe(CN)5H2O]2- + CN-
Removal of all the cyanides if you check the K's proceeds because of the low Ksp of iron hydroxide. BUT its all very slow and inefficient. In
practice my method is better: simplest method imaginable - no mixing, weighing etc; takes a few hrs; directly gives pure KCN; is safe for
non-specialist labs - no HCN at any stage
Yiled can be improved, but at the expense of a lot more dangerous work. At this level I think this method is perfect.
[Edited on 24-2-2009 by len1]
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S.C. Wack
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| Quote: | Originally posted by len1
Thanks for the info SC Wack. But none of the links work. The first two only give me the title pages the last hangs the computer
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As I told Sauron to some argumentation last week, the Google links work perfectly for those in certain countries, like the USA, however Polverone
deleted my explanation on how others can get around this so I ought not post it again. Nor is there anything wrong with the pdf, I'm always the first
one to download to make sure it works and it just worked again. All attachment downloads in the past few months stop at say 98% for 10 seconds then
finish. Maybe its a virus scanning thing or something, or just a problem, in any case that's the way it is and they always finish for me.
[Edited on 24-2-2009 by S.C. Wack]
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not_important
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For me the attached PDF stalled closer to 20 seconds, but did finish and yield a readable file.
The Google links work when accessed through a proxy in the U.S. It is amusing to read
| Quote: | In 1837 Neilson first introduced the use of the hot blast at the Clyde iron furnaces. Shortly afterwards,1 a peculiar exudation of fused salt which
hardened on reaching the air to a white, opaque mass was noticed upon the walls of the furnace near the boshes. The substance was regarded with much
curiosity and it is related by Clark, who made the first analysis of the product, that its alkaline character was soon discovered by the
workman and that it was used by the wife of one of them, for a time, as a substitute for soap in washing clothes.2
Clark's analysis allowed it to contain potassium cyanide 43.4%, potassium carbonate 45.8%. No ferrocyanide was present. |
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len1
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| Quote: | Originally posted by not_important
it was used by the wife of one of them, for a time, as a substitute for soap in washing clothes.2
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I guess it was a very short time ...
A useful thing I found when working with cyanides is to have a developing solution - a few specks of FeCl3 (PCB etchant) and a few specs of FeSO4
(garden fertilizer) dissolved in 10ml H2O, dab it around the lab to locate specs of KCN which might have been left lying around. Even traces of KCN
give an intense blue colouration (as of course would ferro/ferri cyanides)
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Magpie
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len1, there is the Liebig method for the determination of cyanide. This may be of help in your optimization. I've extracted this from "Quantitative
Analysis," 3rd Ed, 1951, p.305, by Pierce & Haenisch, as follows:
"Procedure. To the dissolved sample (note 1) which should contain 6-8 mmol of cyanide ion, add 30-40 mmol of ammonium hydroxide and
0.1-0.2 g potassium iodide, and dilute to a volume of 100 ml. Titrate with standard 0.1M silver nitrate until the addition of 1 drop of reagent
causes the appearance of a permanent turbidity in the solution (note 2).
Notes. 1. Keep constantly in mind the very poisonous nature of potassium cyanide. Be sure to wash out the solution with a large quantity
of water at the conclusion of the determination. Do not allow any waste cyanide to stand in a sink where it may come in contact with acids and evolve
hydrogen cyanide gas."
The reaction up to the endpoint is:
Ag+ + 2CN- ----> [Ag(CN)2]-
So, for every mole of Ag+ consumed there was 2 moles of cyanide present.
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len2
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Thanks Magpie.
One thing i was trying to avoid is using silver - why is it so popular in titrations of CN? Its $55/10gms. So for 8mmol a sinle titration is $2.40!
The other thing is AgCNO is also insoluble. Is there any statement to the effect of cyanates? I suppose i could make some cyanate and see.
[Edited on 26-2-2009 by len2]
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