Alastair
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Allyl chloride (bromide)
Allyl alcohol
4. To determine the purity of any sample of allyl alcohol, 1 cc. is run into 15–25 cc. of carbon tetrachloride and this solution is then treated in
the cold with a carbon tetrachloride solution of bromine (standardized with potassium iodide and sodium thiosulfate) until a permanent bromine
coloration is obtained. The amount of allyl alcohol present in any solution may alsobe determined roughly by conversion to allyl bromide. From
several experiments it was found that the allyl bromide obtained was equivalent to the amount of allyl alcohol as determined by bromine
titration.
I wouldnt mind having this reagent but bromine is quite difficult to find. Maybe substituting it for Cl in this reaction could afford heating
propylene with chlorine at 500 °C?
I found this just a few minutes ago, so i didnt think it over, maybe this will prove useful for brainstorming 
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Alastair
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''In a 2000ml beaker add 602g of concentrated sulfuric acid to 495.9 water (always add acid to water, not water to acid). Cool solution in an ice bath
and add 607g (5.9 moles) of sodium bromide (or 702g potassium bromide) with stirring. Keep the solution cool and stir for a few minutes. Filter off
any solid material.
Pour solution into a 3000m1 boiling flask and place in the following apparatus. Add 324g of 72% allyl alcohol to the flask. Then slowly add 300g of
concentrated sulfuric acid through the separatory funnel with stirring from a magnetic stirrer. The allyl bromide will completely distill over in
about 1 hour (add your sulfuric acid at approximately this rate). Wash the crude bromide with dilute sodium carbonate solution, dry with calcium
chloride (dry when no more calcium chloride clumps together), filter out calcium chloride, and then redistill. The product boils from 69-72 degrees C.
Yield 92-96%.
''
Or replace salt to NaCl here?
[Edited on 15-11-2011 by Alastair]
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AndersHoveland
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I have some information about this compound, because allyl chloride is one of the precursors in one of the synthesis routes for the energetic compound
TNAZ.
Synthesis of 3-hydroxy propylene CH2=CHCH2OH
A mixture of 500g anhydrous oxalic acid and 500g of glycerol was heated under reduced pressure, using a hot water bath for at least 4 hours until
formic acid ceases to distill over. The mixture was then gradually heated to 240degC (under normal pressure) the flask being fitted with a
fractionating column. At 220-225degC carbon dioxide is given off and a mixture of approximately equal amounts of 3-hydroxy propylene and allyl formate
distilled, leaving a residue in the distillation flask containing about half of the glycerol initially used. only minute traces of acrolein is
produced in the reaction. The distillate was treated with 50g NaOH in 1L water to hydrolyze the formate). This is distilled after waiting 6 hours. The
first 300 mL of distillate contained all the allyl alcohol, which after fractionation yielded 200g of a allyl alcohol/water mixture (bp 87-88C) which
may be dehydrated using dry K2CO3, yielding approximately 150g of anhydrous 3-hydroxy propylene.
The glycerol residue left can be resused if the procedure is repeated. The yield of allyl alcohol is nearly quantitative calculated on the amount of
glycerol reacted. Note that formic acid is produced in the reaction. Alternatively, glycerin and formic acid may be used to make 3-hydroxy propylene
instead, see the "organic precursors 2" section.
3-hydroxy propylene may be converted into 3-chloro propylene. This may be accomplished using acetyl chloride CH3C(=O)Cl, which can be prepared by
reacting glacial acetic acid with SCl2.
For making the 3-chloro propylene from propylene alcohol
CH2=CHCH2OAc is reacted with 8 equivalents of acetyl chloride, in ethanol at 30degC for between 15-150 minutes, to form
CH2=CHCH2Cl.
"Ac" represents an acetyl group, of course.
As for the bromine, it can easily be prepared by reacting sodium bromide with a mineral acid and hydrogen peroxide. The bromine can then be drawn into
a separate layer of kerosene, if it is desired to exclude water. But such a solution needs to be used immediately (preferrably within 20 minutes),
because halogens slowly react with alkanes through a radical cascade mechanism, especially in the presence of sunlight or fluorescent light.
[Edited on 15-11-2011 by AndersHoveland]
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madscientist
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Source for your procedure?
I weep at the sight of flaming acetic anhydride.
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AndersHoveland
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sorry, I never saved the source, but I think the first part came from OrgSynthPrep.
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ThatchemistKid
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The first part did come from orgsynth, I have used that procedure before in an attempt to make allyl alcohol, they mention that the temp should be
closely watched, If you are not careful with the temp or do not have a high temp thermometer it is easy to form acrolein as a by-product and trust me
it is no fun.
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turd
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I'm not sure what this thread is about.
If it is about making allyl bromide, just a heads up from someone who did the whole thing from glycerol:
1) Allyl alcohol is a lachrymator. If you plan to suction filter off your drying agent, you better have a fume hood or perform this outside.
2) Allyl bromide is unstable. Mine went red in only one week. I don't know if this was caused by impurities or if you also need a stabilizer for pure
allyl bromide. In any case I dumped it. So either prepare directly before use or add a stabilizer.
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Alastair
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Thanks, ill keep that in mind.
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ChemistryGhost
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Maybe allyl chloride can be made by reacting allyl alcohol with hydrochloric acid. Then finding a way to shift the equilibrium toward allyl chloride.
"Imagination is more important than knowledge" ~Einstein
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smaerd
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Reacting with hydrochloric acid could form the substitution product of the double bond?
How about this, form the tosylate(will hydrolyze over time). The tosylate will be easier/safer to purify as it would be a solid at cold temperatures,
significantly easier to dry and handle. Then if need be form the bromide, chloride, or iodide by substitution insitu or right before use(if the
tosylate does not suffice). In theory the halogens are poorer leaving groups and will replace the tosylates to some extent over time.
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Nicodem
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The synthesis of allyl chloride by the reaction of allyl alcohol with hydrochloric acid is a traditional route to this product. CuCl is commonly used
as a catalyst to speed up the reaction. A typical procedure is published in Comprehensive Practical Organic Chemistry: Preparations And
Quantitative (V. K. Ahluwalia, R. Aggarwal) page 18.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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smaerd
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Thanks, I didn't actually look into it before posting which was a mistake. My suggestion can be neglected thanks for the correction.
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