Author Topic: MeI methods  (Read 2788 times)

0 Members and 1 Guest are viewing this topic.


  • Guest
MeI methods
« on: September 12, 2000, 05:18:00 AM »
different ways to make MeI for whatever you want it for:

1.  MeSO4 + KI --> MeI

2.  Slowly distill MeOH w/large excess of HI

3.  electrolysis of an aq. solution of K acetate w/ I2 or KI

4.  KI + Me-p-toluenesulfonate

5.  methanol + PI5 (in MeI {of all things})

6.  MeOH + PI3  or MeOH + P(yellow or red) + I2

#1.  weinland and schmid, ber. 38, 2327 (1905); ger pat. 175,209 [Frd 1. 8, 17 (1905-07)].

#2.  Norris, Am. Chem. J. 38, 639 (1907).

#3.  Kaufler and Herzog, ber. 42, 3860 (1909).

#4.  Peacock and Menon, Quart. J. Indian Chem. Soc. 2, 240 (1925); Rodionow, Bull. Soc. Chim., 39, 305 (1926).

#5.  Walker and Johnson, J. Chem. Soc. 87, 1595 (1905).

#6.  Dumas and Peligot, Ann. 15, 20 (1835); Ipatiew, S. Russ. Phys-Chem. Soc. 27, I, 364 (1895) [Ber. 29(R)90(1896)]


  • Guest
Re: MeI methods
« Reply #1 on: September 12, 2000, 06:50:00 AM »
Very good overview, no bla bla bla...  :)
Like the third because you only need KI + OTC stuff, will get the paper next time in the library.


  • Guest
MeI and alkyl iodide synthesis
« Reply #2 on: April 21, 2002, 06:06:00 PM »
Okay we have Rhodiums Synths

Here is a possible variation on the RedP procedure above.
Improved preparation of methyl iodide    
Kizlink, Juraj; Rattay, Vladimir.  
Chem. Listy  (1980),  74(1),  91-2. 
MeI was prepd. in .apprx.90% yield by the red P-catalyzed reaction of MeOH with I2.  The reaction rate was controlled by the rate of addn. of MeOH to a mixt. of I2 and P.

I'll add a few more.

Alkyl iodides.

Patent US3053910

Alkyl iodides were prepd. by treating a dialkyl sulfate at pH 1-6.5 with an iodide prepd. by the action of a reducing agent, e.g., Al, Fe, Sn, SO4, oxalic acid, or N2H4, on an aq. slurry of elemental iodine.  In an example, 241 g.  Fe powder was added to 820 g. H2O and 1050 g. com. iodine during 2-3 hrs. at 20-60°, at pH 5.3.  Et2SO4 (1540 g.) was added dropwise at 70-80°, while distg. the EtI as formed.  The reaction mixt. was heated to 95° to complete the EtI distn., and the product was washed with cold H2O, 5% N2CO3, and dried (CaCl2) to give 99% EtI.  Similarly prepd. were 99.1% MeI, 97.2% PrI, and 99.4% AmI.

Preparation of alkyl iodides or aryl iodides.

Patent JP62246527

Alkyl iodides or aryl iodides, useful as methylating agents and cocatalysts for carbonylating agents, were prepd. by a reaction of group IA, IIA, IIIA, IB, IIB, or IVB metals and iodine or iodides of metals and alcs., carboxylic acid esters, dialkyl ethers, and/or diaryl ethers at 15-150° and 1-50 atm without formation of H2O and corrosive materials.  Thus, a soln. of iodine in AcOMe was added dropwise to a mixt. of Al and AcOH over 60 min and then heated at 65° for 150 min to give 65.4% (based on iodine) MeI.

Methyl iodide.
Zadorozhnaya, I. E.   
Khim. Reaktivov Prep.  (1967),  No. 15  96-7.
MeI was prepd. in 91.5% yielded by adding 1.55 kg. PhSO3Me dropwise to a soln. of 1.35 kg. NaI in 1.35 1. H2O, first at room temp. until one third of the ester had been added, and then at 60-70° in a system which provided for distg. the product at this temp. into a receiver contg. ice and H2O.

Antoncho might find this one funny  ;)

Preparation of alkyl halides and sulfur from hydrogen sulfide, alcohols, and halides

Patent US3649197

Alkyl halides were prepd., by reaction of H2S, Br or I, and EtOH or  MeOH in the presence of an alkali metal halide and, optionally, a hydrohalic acid, in a 2-stage reaction.  Thus, a mixt. of EtOH, Br, LiBr, and 12M HCl was treated with 15 psi H2S, S filtered, and the filtrate heated 2 hr at 130° to give 65% EtBr.  Similarly prepd. were 89.0% EtI and 43.0% MeI.

Alkyl iodides

Patent JP50121205

Alkyl iodides were prepd. by treating fatty acid alkyl esters with stoichiometric amts. of metal iodides at 100-250°.  Thus, a mixt. of 2.02 g Me oleate (I) and 10 g CaI2 was stirred 2 hr at 200° under N to give 6 g MeI (purity 99%).  PrI was similarly prepd.; MgI2, MnI2, LiI, AlI3, and SrI2 were also used in place of CaI2.  AcOMe was also used in place of I. 

Methyl iodide.

Patent CS164707

Hot aq. KI was continuously treated with a 3:2 mixt. of H2SO4 and MeOH, and MeI was gradually distd. in 90% yield.

Hydrogen iodide, lithium iodide and methyl iodide.

Patent US4302432

HI is prepd. by reaction under anhyd. conditions of H2 and I2 in a non-alc. solvent using a homogeneous Rh catalyst [e.g., Rh2(CO)4Cl2].  LiI and/or MeI are obtained by including LiOAc and/or MeOAc in the reaction medium.

Anhydrous alkyl iodide.

Patent EP46870

Anhyd. RI were prepd. by treating R1CO2R (R = C1-4 alkyl; R1 = H, C1-8 alkyl or aryl) with iodine and H (and optionally CO) in the presence of a Pt metal compd. as catalyst and a quaternary heterocyclic N compd. or quaternary P compd. as promoter.  Thus, 250 g AcOMe, 50 g AcOH, 60 g N,N-dimethylimidazolium iodide, 1.2 g [Rh(CO)2Cl]2 and 50 g iodine were pressurized with 2 bar CO and 4 bar H, then stirred 58 min at 373 K to give 99.6% MeI.


  • Guest
« Reply #3 on: April 22, 2002, 04:43:00 AM »

Hot aq. KI was continuously treated with a 3:2 mixt. of H2SO4 and MeOH, and MeI was gradually distd. in 90% yield.

oh my God! Is it true?

unfortunately, this patent (i guess, Poix also meant this one) is unavailable at Espacenet...

The thing that really confuses me is the reverse order of addition as well as usage of water. It's been always my impression that the more concentrated the hydrohalic acid is, the better is the conversion - and in this example we have an essentially small concentration of acid all the time...

Of course, that would bee good for not oxidizing HI formed into iodine - but if MeI formation is possible w/such low conc. aq. HI, then - why noone ever just did it w/MeOH and aqueous HI???

Anyone has any thoughts on this?


P.S. Foxy2 rulez! Thanks a lot!


  • Guest
Two tried-and-true ways to make MeI !
« Reply #4 on: April 26, 2002, 03:25:00 PM »
Recently, two bright and enthusiastic Russian hallucinations - namely, Someone-Who-Isn't-Vitsh and Someone-Who-Isn't-Antoncho, decided to undertake a quest to find some properly working pathways to methyl iodide, a much needed reagent in the field of kitchen synthesis, or Young Chemistry, as it is proudly known at HyperLab :) .

And - lo and beehold! - both of them hallucinations succeeded, thus having developed two different tried-and-true ways of synthesizing this substance from completely OTC ingredients.

Here goes:


To 40 g iodine there was added 50 mls MeOH and 3,2 g Al foil in small balls. The mixtr is warmed up a bit until the rxn starts and immersed into cold waterbath as needed to control the rxn.
After the rxn is finished, there's added a mixtr of 30 ml aqua and 20 ml H2SO4, pre-chilled in a freezer. The addition was planned to bee done drop-by-drop w/stirring, but the mixtr thickened so much that 20 more mls MeOH had to bee added and the addition of the acid further carried in portions.
After all was added and well mixed, distilliation of MeI is begun, with the end of the condenser immersed into cold water. At 1st some H2S is emitted and the water in the receiver gets milky.
When all of the product has been distilled, the water in the receiver is saturated w/NaCl and the product is pulled out w/a syringe.

Yield of the crude MeI is 55%.
Sidenote: should bee much better with usage of H3PO4, don't you think so? It would react w/AlI3 quantitatively w/out any oxidation!


36,6 g potassium iodide and 20 mls water are placed into a 100 ml FBF and plugged w/a 2-hole stopper.

One hole of the stopper is fitted w/a distillation condenser (end immersed into a beaker w/cold water) and into the other is stuck a plastic syringe (SWIA doesn't have a pressure-equalized addition funnel of such size) with 20ml ~82% HMeSO4 (made from 50mls MeOH, 50 mls H2SO4, 24 g Na2SO4).

The mixture is heated on a waterbath to 80-90 C, KI dissolves and addition of the acid is commenced. The mxtr immediately turns dark brown and some H2S is given off. However, it very soon stops and oily drops of MeI appear in the condenser.

The addition was carried for ~5 hrs (SWIM was particularly sloppy that time, adding acid irregularly, at the end sayin 'fuqit' and going to bed - at 4am in the morning), and the theoretically calculated qtty of the acid wasn't enough - total of ~35-45 mls was added. SWIM is certain though, w/the use of an addition funnel, it would take much less time.

Addition of each new portion of acid (usually followed by shaking the flask :)  - OTC mag stirrer, so to say :) ) caused a very visible increase in MeI production, however near the end that effect ceased, and purple vapors began to appear. The distillation was stopped when separation of MeI (and SWIA's patience) almost ceased (however, in the morning there was ~0,3-0,4 mls of the black product under the layer of solidified salt, which SWIA didn't bother to extract).

The yield of the crude product was 10,5 mls, which equals to 77% of theory.

Two sidenotes:

1) Naturally, SWIA was surprised out of his mind to see the reaction WORK! From theoretical viewpoint it was simply inconceivable, but nevertheless - real!
On spending some time in pondering over this obvious
cognitive dissonance, though, he arrived at a reasonable explanation:
KI and iodine, initially formed in situ, produce a triiodide ion. The latter, being a much stronger oxidant than mere iodine, forms an equilibrium with sulfuric acid, re-oxidating it back to SO4++, once it's reduced by 'simple' iodide ions, which still are prevalent in the solution. HI is formed as a result of reaction between I3- and H2S.
Which leads us to some further conclusions.

2) It was noted that when too large a portion of HMeSO4 was added at once, some gas was generated - probably, H2S. It is SWIA's deep conviction that a higher yield may bee easily achieved if proper stirring and an addition funnel are emloyed. The 90% yield stated in the original patent is, in his humble opinion, a reasonably practical figure.
Adding I2 to the soln and pre-forming KI3 bee4ahand might bee a good idea, too.

Antoncho wants, on SWIA's beehalf, thank very much his comrade bees - Foxy2 and Poix for bringing this excellent procedure to his attention!



  • Guest
Another trial.
« Reply #5 on: July 12, 2002, 09:43:00 AM »
95g ammonium iodide were dissolved in min qtty of hot water (heating it on waterbath as dissolution is very endotermic) and warmed to ~80C on waterbath.

To this soln 100ml of H2SO4/CH3OH (1:1 volume-wise) was added in portions of 5mls over 5 hours, distillate being collected under water. No stirring was employed xcept immediately after the addition of acid, when the flask was simply shaken by hand (a stirrer hotplate is something mythical for SWIM :) ). After the end of addition the rxn is held at 80C for 3 hrs, after which time almost no MeI distills over.

On contrast with employing KI as iodine source, there was no salt precipitation in the flask, which presumably had positive impact on yield.

The product after drying amounted to 35mls = 79,5g = 85% yield of theory 8) .



  • Guest
To me it seems strange that methylamine wasn't ...
« Reply #6 on: July 15, 2002, 12:46:00 AM »
To me it seems strange that methylamine wasn't formed from the ammonium ion and the methyl iodide, but the highly acidic conditions maybe renders the ammonium ion non-nucleophilic?


  • Guest
But of course not!
« Reply #7 on: July 15, 2002, 08:31:00 AM »
But why, Chief, AFAIK, you can't methylate an ammoniac ion, can you?

I mean, it is actually electropositive after aquiring an extra proton.

In any case, practical evidence shows no significant MeAm formation - as the water in the receiver quickly beecomes acidic, MeAm would've undoubtedly gone into the aqueous layer, even if there was any.



  • Guest
Errr ... not the right logic
« Reply #8 on: July 15, 2002, 10:26:00 AM »
The old fashioned way of making methylamine uses ammonium hydrochloride and formaldehyde.  That is plenty acidic. Don't know why it wouldn't happen but that isn't the reason.


  • Guest
How do you handle MeI?
« Reply #9 on: July 15, 2002, 07:32:00 PM »
Sorry for going off-topic, but I am very interested about methods of handling MeI. I have read some real horror stories about people being hospitalized due to delirium states lasting weeks because of a tiny spill of MeI on the skin. How do you handle this substance, do you use a fumehood and gas masks? Can you e.g. smell it without getting poisoned?

Even more than this I would be interested about the relative toxicity of dimethylsulfate vs methyl iodide.

Thanks for any input.