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Iodoform

mewrox99 - 18-5-2011 at 21:05

Hi Chemists.

I haven't really dabbled much in organic. But I am aware of the haloform reaction and would like to try it out.

I've seen a video on making Iodoform and it seems very easy, but I have some questions.

http://www.youtube.com/watch?v=XoG-suAkI68

1. How do I dispose of the Iodoform. Is there anyway to convert it into safer products

2. How toxic are the vapors? If I work out in the backyard without a mask will I expose my self to too excessive amounts

Neil - 18-5-2011 at 21:41

A good starting point in this journey is...

http://www.jtbaker.com/msds/englishhtml/i3480.htm

Brought to you buy the power of the all knowing all crawling Google bots.

mewrox99 - 18-5-2011 at 22:36

Yes, I read the oxford university MSDS. I find the JTBaker ones a bit overzealous and I'm sure the safety officer at one of the world's most prestigious universities is reliable

In chemistry you need a balance from being overly scared of everything to make phosgene outside without a mask stupidity.

Anyway back to the reaction. One more question most of the texts I have read state to use I2 not his in situ I2. Is his fine

woelen - 18-5-2011 at 22:51

Why dispose of the iodoform? Keep this chemical, it is quite interesting on its own. I also made some and kept it. I have done some other experiments with it, such as pyrolysing the material and doing some organic experiments with it in non-aqueous solvents.

It can be isolated easily, it simply drops out of solution and you can decant the aqueous layer from it and rinse another time with water. I then extracted the material with diethyl ether and let the ether evaporate (outside, while there was a little breeze). The result is a nice glittering solid.

I made a picture of this while it is in its vial.

The procedure, used for making the iodoform is the following:

Dissolve KI in dilute hydrochloric acid and add a slight excess of hydrogen peroxide. This results in formation of solid iodine.
Decant the liquid from the iodine and add water. Stir somewhat and decant again.
Add water again.
Now you have a suspension of iodine in water.
Add some acetone to this and mix well.
Finally, add just enough solution of NaOH, while stirring all the time, such that the brown color of the iodine just disappears. Add one or two drops extra.
Allow the precipitate to settle.

You can do this synth at a scale of a few grams.

[Edited on 19-5-11 by woelen]

The WiZard is In - 19-5-2011 at 06:00

Quote: Originally posted by mewrox99

Hi Chemists.

I haven't really dabbled much in organic. But I am aware of the haloform reaction and would like to try it out.

I've seen a video on making Iodoform and it seems very easy, but I have some questions.

Wow Iodoform brings back a childhood memory —

STRICTLY GERM-PROOF

THE ANTISEPTIC BABY and the Prophylactic Pup
Were playing in the garden when the Bunny gamboled up;
They looked upon the Creature with a loathing undisguised;—
It wasn't Disinfected and it wasn't Sterilized.

They said it was a Microbe and Hotbed of Disease;
They steamed it in a vapor of thousand-odd degrees;
They froze it in a freezer that was cold as Banished Hope
And washed it in permanganate with carbolated soap.

In sulpureted hydrogen they steeped its wiggly ears;
They trimmed its frisky whiskers with a pair of hard-boiled shears;
They donned their rubber mittens and they took it by the hand
And 'lected it a member of the Fumigated band.

There's not a Micrococcus in the garden where they play;
They bathe in pure iodoform a dozen time a day;
And each imbibes his rations from a Hygienic Cup--
The Bunny and the Baby and the Prophylactic Pup.

Authur Guiterman

-------
Monograph Number: 0005033
Title: Iodoform
CAS Registry Number: 75-47-8
CAS Name: Triiodomethane
Molecular Formula: CHI3
Molecular Weight: 393.73
Percent Composition: C 3.05%, H 0.26%, I 96.69%
Literature References: Prepn from acetone, sodium hypochlorite, potassium iodide, and sodium hydroxide: Glass, Q. J. Pharm. Pharmacol. 8, 351 (1935); from chloroform + methyl iodide: Soroos, Hinkamp, J. Am. Chem. Soc. 67, 1642 (1945); by electrolysis: Glasstone, Ind. Chem. 7, 315 (1931). Description of the iodoform reaction: Seelye, Turney, J. Chem. Educ. 36, 572 (1959). Toxicity study: Kutob, Plaa, Toxicol. Appl. Pharmacol. 4, 354 (1962).
Properties: Yellow powder or crystals; mp ~120°; dec at high temp with evolution of iodine. Unctuous touch; characteristic, disagreeable odor. Volatile with steam. d 4.1. Very slightly sol in water. One gram dissolves in 60 ml cold alcohol, 16 ml boiling alcohol, 10 ml chloroform, 7.5 ml ether, 80 ml glycerol, 3 ml carbon disulfide, 34 ml olive oil; freely sol in benzene, acetone, slightly sol in petr ether. LD50 s.c. in mice: 1.6 mmoles/kg (Kutob, Plaa).
Melting point: mp ~120°
Density: d 4.1
Toxicity data: LD50 s.c. in mice: 1.6 mmoles/kg (Kutob, Plaa)
CAUTION: Potential symptoms of overexposure are irritation of eyes and skin; lightheadedness, dizziness, nausea, incoordination, CNS depression; dyspnea; liver, kidney and heart damage; visual disturbances. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 172.
Therap-Cat: Anti-infective (topical).
Therap-Cat-Vet: Antiseptic, disinfectant for superficial lesions and in the female reproductive tract.
[Dispose of it on your GF.]
Keywords: Antiseptic/Disinfectant; Halogens/Halogen Containing Compounds.

Whatever happen'd to — Mercurochrome.

I remember when you couldn't be a Boy Scout if you didn't have it in your first aid kit.

Monograph Number: 0005867
Title: Merbromin
CAS Registry Number: 129-16-8
CAS Name: (2¢7¢-Dibromo-3¢,6¢-dihydroxy-3-oxospiro[isobenzofuran-1(3H),9¢-[9H]xanthen]-4¢-yl)hydroxymercury disodium salt
Additional Names: [2,7-dibromo-9-(o-carboxyphenyl)-6-hydroxy-3-oxo-3H-xanthen-4-yl]hydroxymercury disodium salt; mercurochrome; dibromohydroxymercurifluorescein disodium salt
Manufacturers' Codes: no. 220 sol
Trademarks: Chromargyre; Planochrome; Flavurol; D.O.M.F.; Mercurophage; Mercurocol; Gallochrome; Gynochrome; Mercurome; Asceptichrome; Mercuranine
Molecular Formula: C20H8Br2HgNa2O6
Molecular Weight: 750.65
Percent Composition: C 32.00%, H 1.07%, Br 21.29%, Hg 26.72%, Na 6.13%, O 12.79%
Literature References: Prepd by treating dibromofluorescein with mercuric acetate and sodium hydroxide: White, J. Am. Chem. Soc. 42, 2355 (1920); also prepd by the action of mercuric acetate on dibromofluorescein sodium: Rymill, Corran, Q. J. Pharm. Pharmacol. 7, 543 (1934), see also US 1535003 (1925).
Properties: Trihydrate, iridescent green scales or granules. Freely sol in water, giving a carmine-red soln. Very dil solns (1:2000) possess a yellow-green fluorescence. pH of 0.5% soln: 8.8. One gram dissolves in 50 grams of 94% alcohol, in 8.1 grams methanol: Denoel, J. Pharm. Belg. 22, 423 (1940); 23, 75 (1941). Practically insol in alcohol, acetone, chloroform, ether. Incompat. Acids, most alkaloidal salts and most local anesthetics. Colors the skin carmine-red. The stains may be removed by washing first with permanganate soln and then with oxalic acid soln.
Therap-Cat: Antibacterial.
Therap-Cat-Vet: Antiseptic.
Keywords: Antiseptic/Disinfectant; Mercurial compounds.

http://www.straightdope.com/columns/read/2518/what-happened-...

[Tincture of] Merthiolate —

Monograph Number: 0009317
Title: Thimerosal
CAS Registry Number: 54-64-8
CAS Name: Ethyl[2-mercaptobenzoato(2-)-O,S]mercurate(1-) sodium
Additional Names: [(o-carboxyphenyl)thio]ethylmercury sodium salt; sodium ethylmercurithiosalicylate; thiomersalate; mercurothiolate
Trademarks: Merthiolate (Lilly); Merzonin (Takeda); Vitaseptol (Faure)
Molecular Formula: C9H9HgNaO2S
Molecular Weight: 404.81
Percent Composition: C 26.70%, H 2.24%, Hg 49.55%, Na 5.68%, O 7.90%, S 7.92%
Literature References: Prepd by reacting ethylmercuric chloride (or ethylmercuric hydroxide) with thiosalicylic acid: Kharasch, US 1672615 (1928); Trikojus, Nature 158, 472 (1946); Swirska et al., Przem. Chem. 39, 371 (1960), C.A. 55, 3507a (1961). Toxicity: Mason et al., Clin. Toxicol. 4, 185 (1971). Review of health effects from vaccine exposure: M. Bigham, R. Copes, Drug Saf. 28, 89-101 (2005).
Properties: Cream-colored, crystalline powder. Stable in air, but not in sunlight. One gram dissolves in about 1 ml water, in about 8 ml alcohol. Practically insol in ether and benzene. Stabilization of solns with EDTA: Davisson, US 2864844 (1958 to Lilly). pH of 1% aq soln: 6.7. LD50 s.c. in rats: 98 mg/kg (Mason).
Toxicity data: LD50 s.c. in rats: 98 mg/kg (Mason)
Use: Pharmaceutic aid (preservative).
Therap-Cat: Anti-infective.
Therap-Cat-Vet: Antibacterial, antifungal (topical).
Keywords: Antiseptic/Disinfectant; Mercurial compounds.

mewrox99 - 21-5-2011 at 21:47

Just tried the synth.

Worked great, will upload a yt video later

Here is my product:

Has a real strong nasty mothball sorta odour and gave me a slight headache

Disposed of it by heat to decomposition, small batches at a time

[Edited on 22-5-2011 by mewrox99]

woelen - 22-5-2011 at 22:47

Nice to see that you succeeded in making this chemical.

Please post the exact procedure you have used, so that others also can learn from your interesting experience and can repeat the experiment.

mewrox99 - 23-5-2011 at 04:03

I made it as per this youtube video
http://www.youtube.com/watch?v=XoG-suAkI68

I'm uploading my own video soon.

Here are my notes:

Sunday 22nd May - Synthesis of Iodoform

In a 250mL beaker, 12g of KI is dissolved in 100mL H2O
4mL of pharmacy grade propanone is added
150mL of 4% NaClO is added slowly
Initially brown iodine is produced, but this rapidly reacts with the propanone via the haloform reaction to form a yellow precipitate of Iodoform

The solution was left to settle for ca. 10mins

The solid has separated as a big clump at the bottom and filtering is not needed

Iodoform has a sharp mothball like odor that is hard to describe.

When heated strongly with a propane blow torch, Iodoform rapidly decomposes into Iodine and Carbon. It also melts into a red liquid. I do have my concerns about toxic organoiodine compounds, but under extreme heat they SHOULD decompose into elemental iodine and HI. As far as I know there is no risk of a halocarbonyl being formed due to the instability of I2C=O. The oxford msds mentioned an explosion hazard of heating iodoform so it is important to be cautious. The decomposition appeared exothermic.

My iodoform was desposed of by cautious heating to thermal decomposition

AN IMPORTANT WARNING:
Iodoform has CNS effects and special care should be taken to avoid its vapors. I got a sharp but short lasting headache from it

EDIT: Here is my video on Iodoform

http://www.youtube.com/watch?v=vyQmF08tSFY

[Edited on 23-5-2011 by mewrox99]

woelen - 23-5-2011 at 04:35

What you made almost certainly is not pure iodoform. I now clicked the image to see more detail in it, but normally iodoform does not appear in this form. It appears in the form of many beautifully glittering yellow crystals and the type of yellow color also is more intense.

The headache you had might be due to the iodoform, but I suspect that it at least partly is due to breathing of chloroform.

You added bleach to a solution of KI + acetone and you had quite some excess acetone. Now think of what happened. Part of the bleach indeed oxidizes iodide, forming iodine and/or hypoiodite. The alkaline properties of the bleach then allow further reaction and the iodoform is formed. BUT... there is a side reaction. At least part of the bleach will react directly with acetone, giving another haloform reaction. Chloroform is formed as well. And I can imagine that also mixed products are formed being CHClI2 and CHCl2I. The chloroform is a liquid and when mixed with the iodoform it makes a clump which contracts and becomes sticky. The mixed products also could add to this clump-formation and also might make the material look somewhat lighter.

You could try to repeat the experiment as follows:

Dissolve the KI in water
Add some dilute acid (assure there is excess acid, either H2SO4 or HCl or HNO3, does not matter)
Add just enough bleach for complete oxidation of all iodide to iodine. Do not add too much bleach, because that will result in further oxidation of the iodine to iodate. It is better to have a slight excess of KI than an excess of bleach.
Add acetone to the still acidic solution.
Slowly pour solution of NaOH into the solution and stir and keep on adding NaOH until the liquid becomes slightly alkaline.
Now you will see precipitation of the CHI3, it will be more golden yellow and it will form a fine powder or even nice glittering crystals.
The smell will be different, it does not smell like mothball, but it has the typical hospital smell.

Just try it on a small scale.

Why do you use such large quantities of chemicals? I think 12 grams of KI is quite a lot. An amount of 1.2 grams also does the job, especially if you do not intend to keep the result of your synthesis but instead destroy it. Using smaller quantities results in less cost, less waste and less risk in destroying stuff after the experiment.

I would feel quite uncomfortable if 5 to 10 grams of some (for me) uncommon compound starts decomposing exothermically and gets out of control. If only appr. 0.5 grams do the same, then I just would put the test tube in a sink and allow it to roar at me for a few seconds until it dies ;-)

mewrox99 - 23-5-2011 at 04:53

Ok. Moral of the story, follow a proper textbook rather than someone kid on youtube's synth.

Also since i heated the iodoform i probably got some phosgene :O
It's been 26hours with no symptoms

mewrox99 - 23-5-2011 at 05:18

This is scaring me and I'm having a panic attack.

Do you think i breathed in a dangerous amount of phosgene, It's been 26hours no symptoms

woelen - 23-5-2011 at 06:20

Please read my U2U. No, there is no need to panic!

And yes, some kid with a kewl video on YouTube is not a proper source for information about potentially risky syntheses. In this case you need not worry about your health, but of course, things can turn out less pretty with other syntheses.

There simply is too much crap on YouTube. Only a few channels have good information and most of these good channels are from sciencemadness members

And no, I do not have a channel on YouTube, I have enough work with my own website.

[Edited on 23-5-11 by woelen]

Jor - 23-5-2011 at 07:07

Please tell me how you get phosgene by heating iodoform

mewrox99 - 23-5-2011 at 08:06

@jor it had chloroform in it

Jor - 23-5-2011 at 08:40

You mean as a byproduct of the reaction? If you filtered and dried it properly, it should be free of chloroform. On the phosgene: heating chloroform in glass from below will simply produce chloroform vapours, not phosgene. Unless you direct the flame directly on the vapours or strongly heat the vapours.

What I don't understand is why you destroy the iodoform after you have made it.
And there is no need to panic attack. Unless you get in pain the chest and/or difficulty breathing I would not worry.

And even then the difficulty breathing might be a mental thing

. I exposed myself to a LITTLE bromine (just smelling it) the first time I made it. Then I started thinking about every breath I took and tried to breath in very deeply. Then you will get the impression you can't breath properly

Quite funny, as other one other time I overexposed myself to bromine (this was my only overexposure to an acute poison in my almost 5 years of home chemistry, when I didn't have a fume hood). This happened when I was making it outside, and my sense of smell was lost, and there was slight irritation all the time (for IIRC 30-45 minutes). So I would guess this was an exposure level of about 5ppm. Left me with a light pain in the chest for the evening wich dissappeared after sleeping.

woelen - 23-5-2011 at 09:40

If you read how mewrox99 made the CHI3, then you imemdiately see how it can be contaminated with CHCl3. If this synthesis is done in the proper way, then no CHCl3 will be formed at all.

Jor - 23-5-2011 at 10:14

Yes sorry, my mistake. I guess I read it too fast and skipped over the chloroform part

mewrox99 - 23-5-2011 at 13:39

its morning now and i'm fine. At the time of my last post it had been 32 hours after exposure not 26. Now its 40hours and i havent coughed so im def. fine. Given also i decanted the iodoform and made sure it was almost completly dry. the amount of CHCl4 would be neglible

The WiZard is In - 23-5-2011 at 15:20

Quote: Originally posted by mewrox99

This is scaring me and I'm having a panic attack.

Do you think i breathed in a dangerous amount of phosgene, It's been 26hours no symptoms

If you die — can I have your chemistry set?

If you want to know how a chemist would make idoform —
Vogel's Practical Organic chemistry has it laid out step by step.
You can DL it from the forum's library.

"If you download only one book of practical organic chemistry,
make it this one. It is a classic of laboratory chemistry, well-suited
to the advanced home experimenter."

Being an Analogue person I just purchased a copy of the
3rd ed. US $19.95. I sold another one of the children for medical
experiments so I have a few spare bucks to spend on books &c.

Phosgene. Ye old EB Vedder The Medical Aspects of
Chemical Warfare 1925 sez.

... the results of gassing are more insidious in their action. [Compared to chlorine.]

"After the second or third day if death has not occurred,..."
you still have to pay your credit card bills.

One of quickest easiest ways of producing phosgene is with
carbon tetrachloride and hot metal. In my youth all NYC
subway cars had CCl4 fire-extinguishers....!

Jor - 23-5-2011 at 15:33

''One of quickest easiest ways of producing phosgene is with
carbon tetrachloride and hot metal. In my youth all NYC
subway cars had CCl4 fire-extinguishers....!''

Even more easy is heating a mixture of a dichromate in conc. H2SO4 and chloroform. The gas simply bubbles out of solution, below the boiling point of the chloroform.

mewrox99 - 23-5-2011 at 15:34

Just under 48hours with not a single cough. I'm fine

I looked it up, Phosgene takes no longer than 48hours to take effect with most symptoms usually occurring within 12hrs after exposure,

@Jor
Is that what myfanwy94 did

[Edited on 23-5-2011 by mewrox99]

Jor - 23-5-2011 at 16:15

Now that I think of it, I read on wikipedia that phosgene reacts with sulfur dioxide to form thionyl chloride and carbon dioxide. Now this is very interesting as phosgene is so easily produced. I recently bought a lot of glassware, so I might be able to do this on a small scale.
My idea, generating phosgene from chloroform in a SMALL apparatus (such there is very low space volume except for the liquids, meaning that little phosgene just hangs around in the apparatus making opening the apparatus after the rxn a hazard), and leading it into ice cold xylene (or toluene, but seperating the SOCl2 might be hard). There will have to be a tube from this leading into ammonia.
Next take this solution in a 3-neck with a condensor and CaCl2-guard and bubble in dry SO2 dried with H2SO4. Boil the solution briefly to eliminate all excess COCl2 from the system, during this step I will put a large dish containing hot ammonia in the hood so most COCl2 will leave as urea.

A few question though:
-Does anyone have a reference how fast this reaction with SO2 is? Do they also react in the gas phase? I don't want the bubbling into the xylene cause COCl2 to leave unreacted, wich would mean dimished yeilds and phosgene release. If they react in the gas phase, the SOCl2 will condense and drip back.
-Besides from CaCl2 in the guard tube in the condensor, is there a solid wich I can also put next to the CaCl2 (with cotton in between) wich will effectively remove all phosgene from the exit stream? I was thinking some solid alcohol, but I don't have any. Will tartratic acid or malic acid do fine?
-Does the reaction also work with Na2SO3 anhydrous? This is much more convenient than bubbling SO2 in the liquid, wich will cause excessive evaporation of SOCl2 and some COCl2.

Ofcourse if I do this I will do it in my hood at full power and sash down. Besides, when I open the apparatus, I will boil a dish of ammonia just below the duct to destroy all phosgene so hardly any is release in the air outside. And I will wear a wetted (with water or maybe 10% EtOH) powder mask (how do you call it in English

) around my mouth. Maybe overkill, but this gas is so lethal that I can't take risks.

ScienceSquirrel - 23-5-2011 at 16:39

You should not consider making and reacting phosgene without a schlenk line, gas scrubbers, an efficient hood, gas testers and all the other gear that makes really nasty chemistry safe in a professional environment.

mewrox99 - 23-5-2011 at 16:40

I thnk you should make a difrent thread for that. So just to confirm 44 hours and nothing means im fine? I also forgot 2 mention that after heating it with the blowtorch there was some mess on the pan. I cleaned it with a paper towel and burnt said paper strongly with the bt. I hope that doesnt change anything. I have NO symptoms but still concerned. Should i get my lungs x-rayed?

[Edited on 24-5-2011 by mewrox99]

Sedit - 23-5-2011 at 17:45

Jor please do make another thread for that and if possible leave the title open for other Sulfur halide synthesis

I really want to try my hand at SO2Cl2 synthesis some time and it would be great to see some other synthesis for these form of materials. I recently found a patent that makes it seem as simple as feeding SO2 and Cl2 into Ethylacetate solution as a catalyst. My computer is crashed so Ill have to look for it again but it should be no problem.

cyanureeves - 23-5-2011 at 18:54

would i be able to make some iodoform with some tetraglycine hydroperiodine? it readily turns orange with just water. maybe if i dissolve in in water, add the acetone then the sodium hydroxide solution. anything but phosgene! because i wouldnt mind making my own antiseptic. every time i go to my work shed there are always sulfuric fumes of sorts or hydrochloric and it attaches to the sweat on my face and itches. also there is carbon dioxide for sure from spills on wood etc..and gnats love that stuff. i've never had a good complexion but damn, bumps at fifty?people might stop shaking hands with me.

Sedit - 23-5-2011 at 20:05

It sounds like water purification tablets. I handled them years ago the same way I handled Povidone iodine. Mix it with NaOH and heat it till your left with nothing but ash which contains your NaI. Dissolve in water and filter. Proceed as you normally would with NaI solutions.

cyanureeves - 24-5-2011 at 11:31

well i heated the water purification tabs with sodium hydroxide then added water and got no iodine color. so i added a dash of acetone and h2o2, then a about 100 ml of bleach and it all fizzed but no orange color. i did get to smell the cut grass odor though i did not take deep whipfs. i must say it is very,very pleasant smelling though not watermelon-like as my cut lawn,but better than chloroform. i then added about 15ml of sulfuric acid and instantly the whole thing turned orange and my shed smells like betadine now. i think i see a precipitate also.

mewrox99 - 24-5-2011 at 23:19

Is this cut grass odor phosgene?

ScienceSquirrel - 25-5-2011 at 02:23

Quote: Originally posted by mewrox99

Is this cut grass odor phosgene?

mewrox99 - 25-5-2011 at 02:40

Speaking of phosgene. It's now been 80 hours since that whole scare I had. With zero symptoms I guess this is an appropriate song

http://www.youtube.com/watch?v=Y6ljFaKRTrI

cyanureeves - 25-5-2011 at 04:45

no not phosgene or i'd be dead but not chloroform either. i did smell chloroform at first of course with the acetone. this mixture is a chameleon like solution, yesterday it was orange then it went white when i added more bleach, then it went back to orange as it sat in the sun.this morning in my shed its white again. i think i'll just buy potassium iodide.yep youre still alive and soon you will be back rockin to highway to hell. such ungratefulness!

Jor - 25-5-2011 at 04:51

Quote: Originally posted by mewrox99

Speaking of phosgene. It's now been 80 hours since that whole scare I had. With zero symptoms I guess this is an appropriate song

http://www.youtube.com/watch?v=Y6ljFaKRTrI

Did you heat your iodoform directly with a flame or from beneath in container, and was it still wet? Most likely you did not even make phosgene !

[Edited on 25-5-2011 by Jor]

Dr.Bob - 25-5-2011 at 05:13

Quote: Originally posted by mewrox99

I thnk you should make a difrent thread for that. So just to confirm 44 hours and nothing means im fine? I also forgot 2 mention that after heating it with the blowtorch there was some mess on the pan. I cleaned it with a paper towel and burnt said paper strongly with the bt. I hope that doesnt change anything. I have NO symptoms but still concerned. Should i get my lungs x-rayed?

[Edited on 24-5-2011 by mewrox99]

1) We're chemists, not doctors, but

2) If you have no symptoms and are alive, then you will not likely suffer any ill effects. Without symptoms, most X-rays will not likely show anything useful. Meaning that if you had symptoms, then they might be due to physical problems that show up on an xray. Any remaining long term issues from chemical exposures are very hard to detect by X-rays.

But I know several chemists who have had many exposures to harsh chemicals and if they were fine after a couple of days, they were OK. Two of them are still alive and well after 85+ years, so all chemicals can't be as bad as the media claims.

Bob

PHILOU Zrealone - 25-5-2011 at 06:23

Quote: Originally posted by Dr.Bob

I think he suffers from the survivor paradox symptom

"Hey its 1 hour and I'm still alive!"
"Hey its 2 hours and I'm still alive!"
"Hey its 1 day and I'm still alive!"
"Hey its 2 days and I'm still alive!"
"Hey its 1 week and I'm still alive!"
"Hey its 2 week and I'm still alive!"
"Hey its 1 month and I'm still alive!"
"Hey its 2 monthes and I'm still alive!"
"Hey its 1 year and I'm still alive!"
"Hey its 2 years and I'm still alive!"
"Hey its 1 decade and I'm still alive!"
"Hey its 2 decades and I'm still alive!"
"Heeeyyy iiittttsss 1111 ccceeennttuuurrryyy aaannddd III''''mmmm sssstttiiiillll aaallliiivvvveeee!!!! (But I suffer from Parkinsonian disease...I knew that iodophosgen had injured me in some way"
"Hey its 2 centuries and I'm still alive!"(But answering from the other side, everything is fine, I play with Adam and Grand-Grand-Pa and Mom)"

ROFL-LOL

mr.crow - 25-5-2011 at 09:27

When I was a kid I "accidently" lit a plastic cupholder on fire making a terrible smell. I was sure I was going to die in 2 days.

Why on earth did you heat it? Just keep it in a vial or flush it.

mewrox99 - 25-5-2011 at 20:57

I heated it because I thought that was a good way to dispose of it. If I dissolved it in propanone and flushed it down the sink it would have stank out my lab which is in a fairly confined space (I usually work outside).

The Iodoform was slightly wet and heated strongly with a blow torch.

Anyway, this issue no longer concerns me.

I didn't smell hay so I doubt there was over 1ppm entering my nose and even so it was days ago. I was only worried in the 24-72hour bracket where the symptoms of pulmonary odema can take a little while to manifest. The lungs can't survive that long filled with HCl.

On the topic of phosgene poisoning. I am very surprised I cannot find a single reference online other than hearsay (Just2DIY on yt and him being offline) about his death. Death by phosgene is probably one of the most atypicial ways for a 16 year old to kill himself so I'm suprised it didn't make any news. I've googled his irl name several times

I would have expected an article like this (Phones death)
http://translate.google.com/translate?hl=en&sl=sv&u=...

fficial&prmd=ivns

Mailinmypocket - 26-5-2011 at 16:23

I made a very small quantity of Iodoform this evening following Woelens suggested steps.

1g KI dissolved in 5 ml of 10% HCL

added 7ml of 3% H2O2 (probably could have stopped after 5ml) the typical precipitate of iodine crystals formed, allowed these to settle 5 mins and decanted. rinsed with water.

Added 8ml water followed by 8ml Acetone, and agitated test tube 1 minute.

Added NaOH dropwise (exact quantity not measured but solution used was 1M) until the solution turned bright yellow with quickly precipitating iodoform.

Allowed to settle, decanted. rinsed with DI water and filtered

In the vial shown, is the final product, havent weighed it yet as it is not completely dry.

***I took step by step pictures of my synth however they are too large to attach to the message board

will convert at some point although they are pretty typical images***

[Edited on 27-5-2011 by Mailinmypocket]

woelen - 26-5-2011 at 23:43

This indeed is the right color of the product. Next time you can decrese the amount of acetone. Instead of 8 ml it is OK to use 2 ml. But using more does not harm, it just uses up more acetone than is necessary.

Paddywhacker - 27-5-2011 at 02:11

The OP's method, using hypochlorite and KI makes more efficient use of the KI. You get more iodoform for a given weight of KI.

Making iodoform from iodine, some of the iodine is lost as iodide.

woelen - 27-5-2011 at 04:29

Did you read the rest of the thread? Adding hypiochlorite directly to a mix with iodide and acetone does not only lead to formation of iodoform, but chloroform (and maybe mixed iodo/chloro forms) as well is formed. This is highly undesirable.

I know that 50% of the iodine is converted to iodide, but you can easily oxidize this again with some H2O2 and acid and do the iodoform reaction again. Even a third iteration can be done without increasing the volume of the liquid too much. With 2 iterations, 75% of the iodine is used, with 3 iterations, 87.5% of the iodine is used. You even can keep the iodoform in the liquid if you don't make the liquid too acidic for each iteration.

Mailinmypocket - 27-5-2011 at 04:53

Ok less acetone is even better, I'm planning on scaling up the reaction after work this evening to obtain a few grams worth for future experiments. I didn't really calculate the shoichiometry on this one and to be honest, that's an area of mine that needs more practice. Nonetheless I will reduce the acetone and try again

now as For the efficient use of KI, if the peroxide used oxidizes all of the elemental iodine out of solution, would there really be that much waste of KI? I haven't had a chance to view OP's method yet but I'm assuming that the hypochlorite performs the same oxidation as the peroxide does? Perhaps I will do a side by side test later and see what the differences look like!

Mailinmypocket - 27-5-2011 at 04:55

Quote: Originally posted by woelen

Did you read the rest of the thread? Adding hypiochlorite directly to a mix with iodide and acetone does not only lead to formation of iodoform, but chloroform (and maybe mixed iodo/chloro forms) as well is formed. This is highly undesirable.

I know that 50% of the iodine is converted to iodide, but you can easily oxidize this again with some H2O2 and acid and do the iodoform reaction again. Even a third iteration can be done without increasing the volume of the liquid too much. With 2 iterations, 75% of the iodine is used, with 3 iterations, 87.5% of the iodine is used. You even can keep the iodoform in the liquid if you don't make the liquid too acidic for each iteration.

Wow, you posted that at the exact instant as I posted my last reply, all questions answered, thanks Woelen lol!

trb456 - 10-6-2011 at 09:45

Bringing up this iodoform thread again to ask about purification. I've been reviewing the haloform reaction and Woelen's preparation. Assuming we use acetone as the reactant/solvent, and NaOH as the source of OH-, and strip out/balance all the stages of the mechanism, we get the following balanced equation:

3I2 + CH3COCH3 + NaOH -> CHI3 + CH3COO- + Na+ + 3I- + 3H+

My question is whether or not anything else can be recovered on the right hand side of the equation. Assuming we wash the CHI3 with water, we are left with an aqueous solution of the remaining ions. Everything in sight is highly soluble. The least soluble combination would seem to be sodium acetate, but that's the least interesting thing we could recover IMHO. Also, things may be more complicated than this, given that the haloform mechanism has many stages (see the above link).

This looks like a dead end, but I thought I'd ask a more experienced group. Thanks!

trb456

EDIT: Looking up BPs, it may be possible to distill off the acetic acid and leave behind sodium iodide, but there may be more interactions here that change the BPs in ways I do not know.

[Edited on 10-6-2011 by trb456]

woelen - 10-6-2011 at 11:18

@trb456: A few posts earlier I explained how most of the iodide in the remaining solution can be used for further haloform reaction. In a single step, 50% of the iodine is used, with two steps, 75%, with three steps 87.5% and so on. Three steps most likely is most economical, above that, the hassle of acidifying, oxidizing and basefying becomes too much for the small amount of iodine used for making more iodoform.

------------------------------------------------------------------

I also received a few questions about the reaction of iodoform with chlorine gas. I have done a few experiments to check what happens with this reaction. I found it sufficiently interesting to make a small (text-only) web page about this experiment:

http://woelen.homescience.net/science/chem/exps/exppatt.cgi?...

The second experiment describes what happens when chlorine gas is passed over iodoform. Based on the results of this experiment I'm almost 100% sure that no CCl4 is formed, but only CHCl3 and possibly lower substitution products like CHCl2I and CHClI2.

hkparker - 16-6-2011 at 11:33

I can't believe I didn't read this thread before my iodoform experiments, but I hardly ever go in the organic section here as I usually don't know whats going on. Maybe I should, and force myself to learn something

I tried the bleach method and was really happy with the amount of product I got compared to your method woelen. Didn't realized the chloroform produced was a problem and making mixed halogen haloforms. Guess it was too good to be true, sorry if I ever doubted you woelen

. I'll update my video...

What about the bleach method and bromoform, can we expect the same problems with iodoform? I don't see why not. And if so could I make bromoform by adding sodium hydroxide to bromine and acetone in water?

Lastly, I might have gotten a small amount of iodoform on my skin (impure iodoform, made the bleach way). The rest of the day I felt a little dizzy. an MSDS sheet said that it can be easily absorbed through the skin, is it possible that was the reason I was dizzy?

mewrox99 - 21-6-2011 at 03:21

I doubt it was from Iodoform on your skin. Iodoform was used as an antispetic applied to open wounds.

It was probably CH2ClI or some other compound like that. These compounds are likely to be very toxic and probably is able to be absorbed through skin

woelen - 21-6-2011 at 04:29

As I wrote before, adding bleach directly to a solution of acetone and an iodide (or bromide if you want bromoform) is not a good idea.

You can use bleach, but with the bleach you first must make iodine (or bromine) in somewhat acidic solution. To that you add the acetone and then add sodium hydroxide. Never allow the presence of excess bleach or excess chlorine.

The stoichiometry of the reaction is as follows:

3I2 + CH3COCH3 + 4OH(-) -> CHI3 + CH3COO(-) + 3I(-) + 3H2O

In terms of chemicals it is as follows:

3I2 + CH3COCH3 + 4NaOH -> CHI3 + CH3COONa + 3NaI + 3H2O

You, however, should use excess acetone and excess hydroxide in your experiment. Most expensive is the iodine and you want all of that to be used up.
From this reaction equation you should be able to compute the amounts of chemicals, needed for making e.g. 1 gram of iodoform.

I do not do the computations here (I leave that as an exercise for you guys) but roughly speaking you can say the following:

For each gram of iodine take 1 ml of acetone (large excess) and half a gram of sodium hydroxide (large excess). Dissolve the iodine in the acetone and then add 10 ml of water. Dissolve the sodium hydroxide in another 5 ml of water and add that to the solution. Almost 0.5 grams of iodoform precipitates. This can be scaled up.

If you don't have iodine but potassium iodide:

Take 1.4 grams of potassium iodide. Add 10 ml of 10% HCl or 10% H2SO4 and dissolve all KI. Add excess amount of H2O2 (e.g. 10 ml of 3% H2O2), such that all iodine precipitates and only a fairly light brown solution remains. Let iodine settle, decant the solution, add a lot of water, let iodine settle again, decant the water, and then add 1 ml of acetone. Swirl and let as much as possible dissolve. No need to have all of it dissolved, the iodine is somewhat flocculent and is not compact.
Add 10 ml of water and then add the 5 ml of NaOH-solution with 0.5 gram of NaOH. Just over 0.5 grams of CHI3 will precipitate. Again you can scale up.

If you don't have H2O2 use bleach as oxidizer instead, but assure that no excess is added. Excess bleach redissolves the iodine and will lead to chloroform and mixed haloforms. For this reason the use of H2O2 is highly recommended. Excess H2O2 does not redissolve the iodine.

Keep in mind that only 50% of the iodine is used. After precipitation of the CHI3 you can collect the remaining iodine with acid and H2O2 and use that to make more CHI3. See above in this thread.

Spread the CHI3 on a piece of filter paper to have almost all adhering water absorbed in the filter paper (coffee filter is perfectly suitable for this, but do not use paper tissue or toilet paper). Scrape the solid from the filter and allow to dry outside (not inside, the material has a strong hospital-like antiseptic smell).

CHI3 is easy to store and keep around and does not introduce any special risks in your home lab. Keep in a tightly closed little glass bottle in the dark. It can be used for some interesting experiments, but I would not make more than 5 grams or so. With 5 grams you can do all interesting experiments you might have in mind.

This reply should answer the U2U's I received recently about the making of CHI3.

hkparker - 21-6-2011 at 11:26

Thank you for your time woelen, I appreciate it. Me and mewrox99 both felt a dizzy and anesthesiated feeling on exposure to the impure iodoform. Do you think this is likely from the CHI2Cl and CHICl2 impurities we produced?

woelen - 22-6-2011 at 02:49

I know that CHI3 itself does not induce a strong reaction, unless a lot of this is inhaled. In the past it was used as antiseptic and the people treated with this almost certainly did not have such strong adverse effects.

So, I think that indeed the other mixed halogen compounds cause the dizziness.

Waffles SS - 21-4-2014 at 09:57

What is best ratio of I2,NaOH (or KOH),acetone for making iodoform?

Woelen suggest: 1gr Iodine + 1cc(~0.7gr)Acetone+0.5gr NaOH for making 0.5gr Iodoform

I think this ratio is not true because in excess alkaline Iodoform decompose(probably to Diiodocarbene)

According to Stichometry:

3I2 + CH3COCH3 + 4NaOH -> CHI3 + CH3COONa + 3NaI + 3H2O

761.4 of iodine react with only 58gr acetone for making Triiodoacetone and finally Haloform reaction complete with 160gr of NaOH

Compare 0.5 gram of NaOH for 1gram I2 with Stichometry

1 gr Iodine really need 0.0761 gr Acetone and 0.210gr NaOH

am i wrong?

[Edited on 21-4-2014 by Waffles SS]

woelen - 22-4-2014 at 00:07

The precise ratio is not really important. You want all iodine to be used up, so use excess of acetone and NaOH. You need to do the reaction in dilute solutions and the reaction only runs at high pH, so you need some excess NaOH.

Iodoform slowly decomposes in alkaline solution, but this reaction is very slow. At the amounts I used, this effect is not strong and if you isolate the CHI3 quickly after it is formed, then losses, due to decomposition can be neglected.

By using 1 cc of acetone and 0.5 grams of NaOH you assure that all iodine (if you use a gram) is used up, even if you have no means of weighing accurately. E.g. if you take 0.4 grams of NaOH or 0.6 grams of NaOH and you take 0.9 ml of acetone or 1.1 ml of acetone, it still works. My "recipe" is quite robust.

Waffles SS - 22-4-2014 at 07:05

Thanks,

Are sure about Yield?~0.5 gram from 1 gr Iodine?
(last time i tried 10gr Iodine + 10ml Acetone +100ml H2O and 45.5ml 10% KOH drop by drop but Yield was 3gr)

I want to make 100gr Idoform what is your suggested ratio?(Multiple 100x?)

I use KOH instead of NaOH,what is your suggested method for separating KI from remaining solution(I dont think only evaporation to dryness work well because solution contain Iodoacetone and KOH)

[Edited on 22-4-2014 by Waffles SS]

woelen - 23-4-2014 at 00:23

Yield is appr. 0.5 grams per 1 gram of I2 (half of the iodine ends up as iodide ion, the rest goes into CHI3 and because CHI3 is in terms of weight nearly 100% iodine, I say just a little over 0.5 grams).

Keep in mind that CHI3 is soluble somewhat in water and this may lead to losses and that may be the reason that you only obtained 3 grams instead of 5 grams from iodine.

One way to obtain better yields is extracting all CHI3 into diethyl ether and then let the ether evaporate.

Boffis - 3-5-2014 at 15:20

If its not a rude question, may I ask what's the great interest in iodoform? After all, as far as I know you can't make either a substance to blow you mind or blow your hand off from it, or can you? Or am I being cynical.

IrC - 3-5-2014 at 17:22

Woelen, you said "Dissolve KI in dilute hydrochloric acid and add a slight excess of hydrogen peroxide."

Over the years I see details such as this but they leave me in the dark. One of the reasons I wish I had focused on chemistry instead of electronics. No doubt all the real chemists here already understand exactly what you mean. Mind you I'm not complaining, you are the best chemist I have ever seen online. But what does it mean exactly? What percent is 'dilute' Hydrochloric acid? What percent is the peroxide? Does it mean store bought 3 percent? On the acid, if say one had 37 percent from Home Depot used to clean concrete or whatever, does dilute mean 9 parts water for one acid? How does one know the dilution?

I am not making Iodoform I have no need for it but this thread conveniently mentions two things I read often yet never know exactly what is meant (dilute acid and un-named percent H2O2). Long ago I learned to not keep chemicals unless there is a need or future possible use, after the hassle I had getting rid of many I collected over the years no one would take. Anyway if you could clarify this it would be helpful, since I have wondered over the years many times what they meant when reading statements such as yours quoted above.

woelen - 4-5-2014 at 09:09

The statement, such as the one you quoted, means that concentrations are not critical at all.

In this context, dilute hydrochloric acid can be anything from let's say 3% HCl to 15% HCl, but even these borders are not hard borders. The concentration of the hydrogen peroxide also does not matter, you just have to add enough and then a little extra.

In practice, if I would make iodine from KI, HCl and H2O2 I would proceed as follows.
Suppose I have 5 grams of KI for this experiment.

I would take 10 ml of conc. HCl and add 20 ... 25 ml of water (no precise measurement needed, just roughly) and swirl well. Then I would dissolve the KI in this. This will be easy.
Next, I would carefully add H2O2 (e.g. common 6% stuff, but 3% material will do the job also) until iodine forms a flocculent solid in the liquid and then I would add a little extra.
The resulting liquid then will be brown, but not very strongly brown. The I2 will be present as solid.

Next, I would add a lot of water, allow the iodine to settle, and decant as much as possible of the brown liquid, without pouring away solid iodine. Adding water again, allowing the iodine to settle, and decant again removes nearly all acid. This product is suitable as a start point for making CHI3. No need to isolate the iodine in dry form.

chornedsnorkack - 22-5-2014 at 02:07

So, let´s review the conditions for iodoform reaction... starting from, say, ethanol.
The steps should be:
1) CH3CH2OH+I2+2NaOH->CH3CHO+2NaI+2H2O
2) CH3CHO+I2+NaOH->CH2ICHO+NaI+H2O
3) CH2ICHO+I2+NaOH->CHI2CHO+NaI+H2O
4) CHI2CHO+I2+NaOH->CI3CHO+NaI+H2O
5) CI3CHO+NaOH->CHI3+HCOONa
Is that correct?
This would work if iodine and base are both in excess. But what if they are not? Is Step 1) the rate controlling step such that a limited amount of iodine is converted quantitatively to iodoform and iodide, or does the reaction stop at some step?