Author Topic: allyl iodide: is this article useful?  (Read 2983 times)

0 Members and 1 Guest are viewing this topic.


  • Guest
allyl iodide: is this article useful?
« on: January 31, 2003, 04:48:00 AM »
Bull.Soc.Chim.Fr. 30;1878;126

Action of aluminium iodide on glycerine;

by M.W.R.H.(1).

Dried glycerine is heated in a retort with aluminium sheets. Gradual addition of iodine starts a reaction, which is slow at first, but gets fast and violent soon, reaching 200°C. One notes the formation of hydrogen and a smell of acroleine and an oily iodinated liquid distills over. The residue, which stays in the retort even at 360° is thick and viscous but another quantity of oil can be distilled when heating to glowing red.

The oily liquid, washed with water, dissolved in alcohol and shaken with mercury combines with the latter in an exothermic reaction giving bright yellow splitters, which deposit on cooling and consist of mercury allyl iodide C3H5HgI. The alcoholic mother liquor contains no isopropyl iodide.

The total reaction of aluminium iodide on glycerine is thus described by the equation:
2C3H5(OH)3 + Al2I6 = 2C3H5I + Al2O3 + 3H2O + 2I2
It is comparable to the one of phosphorus iodide

(1) Chemical News, t. XXXV, p. 237

translated from french. (yes, it's the _whole_ article)

that glowing red and > 360° part scares me somewhat and no yield given...
but maybe this is an option for people who can't access rP? maybe vacuum
distilling helps?


  • Guest
« Reply #1 on: January 31, 2003, 12:45:00 PM »
Or they could go out in the garden and shoot themself.
This sounds dangeres. The EthylIodide comes over at 200°C so there is no reason to destil the thick (and non interesting) oil over at glowing red temp. Also there is no reason the isolate the ethyliodide as the mercury compound (it quite toxic). Another (fractional) destilation of the compound would doo the trick.

By the way funny article, from the dayes where chemistry was a real fun.


  • Guest
« Reply #2 on: January 31, 2003, 01:11:00 PM »
so just how dangerous does the practical portion of this article seem?  with vacuum distillation, etc.  doesn't this look ok?


  • Guest
« Reply #3 on: January 31, 2003, 03:49:00 PM »
The EthylIodide comes over at 200°C

They are making allyl iodide, bp 103°C.

And ethyl iodide has a boiling point of 72°C


  • Guest
2 more stone-age allyl iodide articles
« Reply #4 on: February 10, 2003, 04:18:00 AM »
in the series "when chemists were real men" i present 2 more
articles: both are pretty ok yield wise (1000g resp 1100-1150g
allyl iodide from 1000g iodine), both use red phosphorus, the
second one works under CO2 atmosphere. i only bothered to type /
translate the experimental part.

here ya go:

they claim 1000g allyl iodide from 1000g iodine (i think).

The apparatus consists of a retort, fitted with a funnel having a glass stopper. The retort is connected with a condenser and receiver as usual. The retort is kept dipped in a larger-sized water bath, which can be heated from beneath. Glycerol is next poured into the retort and then the iodine, taking care that all of it drops on the glycerol and that none sticks to the side of the retort. When all the iodine is added, the water bath is heated to boiling. A small piece of phosphorus is then added, the stopper of the funnel being removed temporarily. When this comes into contact with iodine in the hot glycerol, it reacts at once. As a result of the interaction, some ally iodide is formed, which takes up some iodine into solution, A second piece is immediately added and takes part in the reaction in like manner. On continuing the addition of larger pieces of phosphorus, more and more allyl iodide is formed, which, taking up  increasing quantities of iodine into solution, facilitates the reaction. After a considerable quantity of phosphorus has been added in this manner, the allyl iodide formed distills off, being heated on the water bath and the heat generated by the reaction. Proceeding in this manner, after the addition of only a few grams of phosphorus (which takes but a short time), large pieces weighing as much as 3-4 g. can be added in quick succession. The operation can, therefore, be very smoothly and quickly completed. Since some isopropyl iodide (b.p. 89°) is invariably produced in this reaction, the mixture boils at less then 100° and, hence, the major part of the distillation is finished on the water bath. The last traces can be distilled off by heating with a constantly moving flame. The allyl iodide is dried and purified in the usual manner.

(transl. from german. note: i'm not sure about some parts of it, see the parts in brackets)

We use 1000 to 2000 g. iodine and per 1000 g. of iodine 3000 g. highly concentrated glycerol and 600 g. of phosphorus. The mixture of glycerol and pulverised iodine is transfered into a big retort equipped with a gas inlet tubed [original: tubulirte retorte !?] which is connected to a recipient equipped with a second neck [original: tubulirten recipienten]. The second neck of the recipient is connected using a glass tube with the fume hood [original: dem luftzug] and the gas inlet tube of the retort with a CO2 apparatus. Once the air inside the apparatus is replaced by CO2, the phosphorus is added in small pieces. The first pieces of phosphorus usually react violently, but the reaction soon calms down; in order to ensure the continuing of the reaction, one has to add bigger pieces of phosphorus or even mildly heat the retort. When all the phosphorus is added, one distills on open flame in a stream of CO2 until the residue starts to foam heavily. The bulk of the allyl iodide is distilled off and the smaller part is gained by rectifying the residue with water vapour. We thus usually obtained 1100-1150 g. C3H5J from 1000g of iodine; iodine of the same quality only gave 700 g. allyl iodide using the method of Claus and Oppenheim.


  • Guest
Could be dangerous
« Reply #5 on: February 14, 2003, 01:48:00 PM »

...the phosphorus is added in small pieces. The first pieces of phosphorus usually react violently, but the reaction soon calms down...

They are talking of pieces of phosphorus. Since the only modification of phosphorus which is sold in pieces, lumps or in the form of sticks is white phosphorus, I think this "antique" procedure works with the white variety.
There must be some reason for the replacement of the air with carbon dioxide in the second article... ::)
Are you absolutely sure they used red phosphorus, is it specifically mentioned in those articles?


  • Guest
good question
« Reply #6 on: February 14, 2003, 02:03:00 PM »
the second one does not mention the type of phosphorus at all.

excerpt from the first one:

"Behal (Ann.,131,58 (1864)) in order to obviate the use of yellow phosphorus, employed red phosphorus in conjunction with a solution of iodine in allyl iodide and glycerol. This method does not, however come under our consideration."

no more mention of phosphorus type after this one.

the reason i said rP is that, iirc, the beilstein ref. said red phosphorus.


  • Guest
I bet they used
« Reply #7 on: February 14, 2003, 02:42:00 PM »
white phosphorus in both methods. But the synthesis of Behal seems to be interesting, as red phosphorus is used here. Maybe this article, "Behal (Ann.,131,58 (1864)", which you had already mentioned, contains the really useful data?
I'd say hunt for it in the library... ;)