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Theoretic
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thumbup.gif posted on 31-10-2003 at 08:40
Ethylene explorations


1)Saturated hydrocarbons (preferably from petrol) => cracking it as far as it goes over a broken pottery catalyst (don't laugh, I know of a school demonstration of cracking crude oil.
Mineral wool soaked in crude oil put into boiling tube and heated, passed over broken pottery - not heated, I remember :o - and ethylene collected in an inverted-in-water test tube).
2)Ethylene passed into a solution of HOCl prepared the following way:
Ca(OCl)2 dissolved in water, than H2SO4 added, CaSO4 precipitates, HOCl left in solution (don't overconcentrate, HOCl doesn't exist freely and in too concentrated solutions either - it converts into Cl2O of which 143g is soluble in 100g water.)
What happens is: C2H4+HOCl=>CH2OHCH2Cl (ethylene chlorohydrone, or chloroethanol if you like).
I'm pretty sure it will form a layer at the bottom - should be good organic solvent.
2)You can convert it to C2H4Cl2 by reacting it with HCl solution (prepared by CaCl2 solution + H2SO4 if that's more convenient than the traditional method):
CH2OHCH2Cl+HCl=>C2H4Cl2+H2O.
3)Alkalyse that (or chlorohydrone) with alcohol solution of NaOH for ethylene glycol:
C2H4Cl2+2NaOH=>C2H4(OH)2+2NaCl.
4)Or: C2H4+HCl=>C2H5Cl.
5)You could make C2H4(NO2)2 by:
C2H4Cl2+2NaNO2=>C2H4(NO2)2+2NaCl.
Or even C2H4+N2O4=>C2H4(NO2)2.
Why not? My chemistry book proposes two mechanisms for the reaction of halogens with alkenes. Both fit N2O4 perfectly (especially the free-radical mechanism :cool:).
6)Then by:
C2H4+H2O=>C2H5OH make your own alcohol from petrol!
7)Then by:
C2H5OH+CuO=>CH3COH+H2O+Cu (I didn't make it up. Honest) make your own acetaldehyde - the easy way!
8)Or: C2H4(OH)2+2CuO=>(COH)2+2Cu+2H2O.
9)Or:CH2OHCH2Cl+CuO=>Cu+H2O+ +CH2ClCOH
10)CH3COH+HCN=>CH3CH(OH)CN.
11)CH2ClCOH+HCN=>CH2ClCH(OH)CN
(1-chloro-2-hydroxy-2-cyanoethane)
12)CH2ClCH(OH)CN+2H2O=>CH2ClCH(OH)COOH+NH3
13)2CH2ClCOH+O2=>2CH2ClCOOH
(there goes chloroacetic acid).
If there was a way to convert -CN to
-CH2OH you could make glycerine!
I've made up some and put all this together myself, so feel free to criticise :D.
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[*] posted on 1-11-2003 at 10:37


I'm pretty sure it won't form a layer at the bottom. chloroethanol is miscible with water (according to CRC handbook)
RCN Hydrolyses to RCOOH, which can be reduced to RCH2OH if you really want glycerine.
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[*] posted on 1-11-2003 at 12:04


Quote:

Ca(OCl)2 dissolved in water, than H2SO4 added, CaSO4 precipitates, HOCl left in solution (don't overconcentrate, HOCl doesn't exist freely and in too concentrated solutions either - it converts into Cl2O of which 143g is soluble in 100g water.)


The hypochloric acid will actually go to chlorine gas, hydrochloric acid, and water in my experience if the concentration gets too high. Chlorine dioxide may be generated but not to any extent worth noteing. I use the same reaction with HCl to produce chlorine gas in my labratory.
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[*] posted on 1-11-2003 at 13:29


If the hypochlorite contains chloride, the reaction will generate large volumes of chlorine gas. If this is an issue, maintaining the solution with some chlorine will work instead. Without chloride, and with a cool solution, something like 50% hypochlorous acid solutions are possible. The ppt of calcium sulphate will prevent anything like this concentration being possible with this setup.

Reaction of the chlorohydrin with HCl is a no go. Reaction of NaNO2 with a haloalkane produces a mixture of nitro and ester products, if the halogen is chlorine sometimes you can get the product, unlike with the usually higher yeilding silver nitrate reaction which gives no product with chlorides at all. Bromides and Iodides are usually much preferred for these reactions. Reaction with N2O4 will certainly produce some vic dinitro compound, but I dont know how much or how stable this would be or under what circumstances the reaction mixture would catch fire/detonate...

I think this list needs detailed information from the lit before anyone should try anything for real. Partially becuase of the dangers, and partially becuase most of these theoretical ideas will fail without specifics.
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[*] posted on 10-11-2003 at 08:03


Quote:
"The hypochloric acid will actually go to chlorine gas, hydrochloric acid, and water in my experience if the concentration gets too high. Chlorine dioxide may be generated but not to any extent worth noteing. I use the same reaction with HCl to produce chlorine gas in my labratory."
:o
How could the hypochloric acid with chlorine oxidation number +1 turn into chlorine (0), hydrochloric acid (-1) and water? Another matter if oxygen is evolved as well. If not then that chlorine dioxide is the product of a disproportionation reaction.
Quote:
"If the hypochlorite contains chloride, the reaction will generate large volumes of chlorine gas. If this is an issue, maintaining the solution with some chlorine will work instead. Without chloride, and with a cool solution, something like 50% hypochlorous acid solutions are possible. The ppt of calcium sulphate will prevent anything like this concentration being possible with this setup.

Reaction of the chlorohydrin with HCl is a no go."
How could the precipitation of CaSO4 prevent high concentration of HClO? I thought it would help not having extra solute. Maybe the precipitate decomposes
the HClO...
And, well, my chemistry book presented me with a reaction CH2ClCH2OH+HCl=>CH2ClCH2Cl.
Another one with
CH2ClCH2OH+H2O=>CH2OHCH2OH+HCl.
It's just a matter of concentration, I suppose. ;)
Quote:
"Reaction with N2O4 will certainly produce some vic dinitro compound, but I dont know how much or how stable this would be or under what circumstances the reaction mixture would catch fire/detonate..."
Well, nitromethane, for example, is very hard to ignite with a match, so I don't think self-incineration is an issue. I don't think it would be unstable either. The reaction mixture with a fair amount of the product in it (suppose it resembles nitromethane) could detonate on being struck with a hammer. :)

[Edited on 10-11-2003 by Theoretic]
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[*] posted on 10-11-2003 at 23:35


Calcium sulphate sludges are notoriosly difficult to filter. Its usually a case of rather dilute solutions or not getting much product at all, if any.

Reaction of ethylene glycol with conc HCl solution, 35% or so will aparently produce a very poor yeild of ethylene chlorohydrin. A decent yeild can be obtained by passing dry HCl gas into anhydrous ethylene glycol. Getting the second OH to replace is considerably more difficult. Unless you were thinking of using more forced conditions than these, its a no go.

Nitromethane might be nice and stable, and the dinitro goal might not be much less stable, but the isomeric nitrous esters that also form are distinctly unstable. Methyl nitrite and ethyl nitrite have this nasty habit of detonating slightly above their boiling points.

Ethene led into an ether solution of dilute nitrogen peroxide at 0C, apearing to a reasonably safe way, yeilds about a 37% product of the 1,2 dinitro compound, with the remainder being mostly compounds with nitro, nitrous ester and nitrate ester groups. I have no idea how these products could be seperated safely. with or without a hammer, and I advise you to think the same until more information can be obtained.

The information might be in the following reference(s),
Baldock, Levy, and Scaife, J. Chem. Soc., 1949, 2627;
Levy, Scaife, and Wilder-Smith, J. Chem. Soc. 1946, 1096.
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wink.gif posted on 11-11-2003 at 08:34


Well, you are right, and it's not only for the would-be organic synthesist that CaSO4 sludges are a pain in the arse (see the "Nitric acid" thread), but why removing it? The sludge could actually be an advantage - slowing down ethylene bubbles so they have more time to react!
So you CAN make ethylene chlorohydrin, and it can be extracted into
water-insoluble organic solvent or by evaporation (water-rich fraction coming off first). Dichloroethane - by straight
addition of chlorine (preferably in solvent - such as CCl4). Ethylene glycol - by hydrolysis of either - ethylene chlorohydrin preferable.
Oh, and HNO2 + alcohols is a way to (theoretically) pure alkyl nitrites - I think.
Quote:
"Unless you were thinking of using more forced conditions than these, its a no go."
Well, I'm starting a thread on chlorination (not substitution) under very chemically forced conditions tomorrow, I don't have time today. :)
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cool.gif posted on 12-11-2003 at 08:51


The HNO2 + alcohols actually produces an equilibrium, COULD be useful. Alcohols + (NO)2SO4 (nitrosyl sulfate) yield alkyl nitrites and sulfuric acid (anhydrousness, pure product upon distillation and ELSE guaranteed.
Anyway, getting back to ethylene derivatives. Forced substitution of hydroxyl for chlorine, I think, could be effected by using anhydrous ethylene glycol (ethylene chlorohydrin, alcohol) with CaCl2 dissolved in it. As soon as water is formed, it would hopefully precipitate and carry down the water with it (as hydrate).
Now I'm thinking of acetylene from ethylene derivatives. Dichloroethane + alcoholic alkali is said to give low yields, so I think Ethylene glycol + sulfuric anhydride on HEATING! Sounds scary, but acetylene is a very endothermic compound, and it's formation is not very favoured. Hot because formation of hydroxyethylene and dioxane (;), ask Organikum) has to be avoided - by using brutal conditions in this case. On second thoughts, you could first make dioxane
(http://www.sciencemadness.org/talk/viewthread.php?tid=55&...) and then dehydrate it to acetylene. :cool:
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[*] posted on 13-11-2003 at 21:02
nitroalkanes via nucleophilic substitution


primary alkyl halides yield mostly nitroalkane. the secondaries yield 15% nitroalkane and tertiary alkyl halides practically don't produce nitroalkane but the nitrous ester.
just found a general procedure for preparation of nitroalkanes in <i>"Organikum, organisch-chemisches grundpraktikum"</i> :
add 0.3 mol alkyl halide to a mix of 0.5 mol sodium nitrite and 0.5 mol urea (increases soloublity of the nitrite in dimethylformamide) in 600 ml dimethylformamide. mechanically stir at room temperature for 1-6 hour (depends on reactivity of the halide). pour the mix on 1.5 L ice water, extract with ether several times, dry on calcium chloride, then perform a fractional distillation using a 30cm vigreux column. the nirous ester by product comes first (has lower bp)
"ethylene chlorohydrine is of course a primary alkyl halide"
when using ethylene chlorohydrine in above procedure. 2-nitroethanol and ethylene glycol mononitrite are expected to form. and both are liquides with high bp. so one can warm the whole batch at 120°C to tautomerise the glycol nitrite to 2-nitroethanol
the nitroethanol can further react with formaldehyde to form trimethylolnitromethane and this makes NIBGTN upon nitration.




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[*] posted on 16-11-2003 at 08:12


Very nice :D, but...
"600 ml dimethylformamide"... "extract with ether several times"... "then perform a fractional distillation using a 30cm vigreux column".
Sounds quite draconian for an apparently simple reaction :D. Well, organic chemistry is deceptive, right? ;) - see http://www.sciencemadness.org/talk/viewthread.php?tid=916&am...
May I suggest a catalyst - AlCl3! When it is dissolved in halogenoalkanes, the solution is weakly conductive due to the equilibrium: AlCl3 + R-Cl => AlCl4 + R+.
And R+ would combine rapidly and irreversibly with NO2-, right?
"...tautomerise the glycol nitrite to 2-nitroethanol "
Nice! Could it be carried out with methyl nitrite or is it only possible if there's more than one carbon atom in the skeleton?
The catalyst for substitution of -OH for -Cl is ZnCl2. So, a solution of CaCl2 in ethyl chlorhydrine, toss in some ZnCl2, and bubble dry HCl - ethylene chloride (toxic stuff)! :cool:
Oh, I nearly forgot! The acetylene production by dehydration of ethylene glycol seems too doubtful. Another method, C2H3Cl or C2H4Cl2 + CaO is much more foolproof. :cool:
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[*] posted on 16-11-2003 at 14:52


Theoretic, it is sometimes difficult to work out who you are arguing with, if more than one person please direct comments.

"The sludge could actually be an advantage - slowing down ethylene bubbles so they have more time to react! "
No, it would prevent the solution from mixing properly, and thus the acid reacting with the gas. It would also intefere with any extraction attempted to recover the product.

"So you CAN make ethylene chlorohydrin"
I cant work out the reason for the emphasis, or who its directed against.

"Alcohols + (NO)2SO4 (nitrosyl sulfate) yield alkyl nitrites and sulfuric acid"
A bad idea, you dont have a problem with the simple dilute HNO2 + Alcohols as the nitrite ester generally forms a seperate layer. Distillation of alkyl nitrites would be another bad idea.


Kaboom,
"primary alkyl halides yield mostly nitroalkane. the secondaries yield 15% nitroalkane and tertiary alkyl halides practically don't produce nitroalkane but the nitrous ester.
"
Silver nitrite can produce 80% yeilds with a primary halide, though not chlorides which dont work at all, sodium nitrite can achieve 60%. With secondaries silver is limited to around 15% but sodium can be over 50% yeild. Tertiaries with sodium nitrite almost universally go to the olefin in majority yeild. Silver nitrite and t-iodides likewise.

"so one can warm the whole batch at 120°C to tautomerise the glycol nitrite to 2-nitroethanol"
Umm, based on what?
Glycol nitrite and 2-nitroethanol arnt tautomers, and nitrites dont rearrange to nitro compounds to any extent Ive been able to find. Is this a reaction youve specifically read glycol nitrite will do or are you just assuming it will?

Theoretic,
"Sounds quite draconian for an apparently simple reaction"
All reactions look simple as an equation. What makes them useful for synthesis is frequently much more complicated. Why DMF? Its one of the two solvents that dissolves enough sodium nitrite to get good yeilds (the other being DMSO). Why urea? Its actually to destroy nitrite esters, which are nitrosating egents and attack the nitroalkane reducing the yeild during the long reaction time in DMF. I am unaware of any changes in solubility due to urea but if this is the case, this could also be a factor. DMSO reactions are usually much faster, owing to a higher solubility of sodium nitrite, and urea can be skipped. The boiling point of DMF is in the same range as the nitro compounds the reaction is producing, for a generic method this needs replacing with a solvent that isnt, hense the liquid liquid extraction step with ether. DMSO is by far preferable for these reactions, and as an advantage is also much less toxic.

"May I suggest a catalyst - AlCl3! "
Lewis acids, ferric chloride and aluminium chloride notably, react with nitroalkanes to form adduct compounds. Nice try though.

"And R+ would combine rapidly and irreversibly with NO2-, right?"
This reaction mechanism (SN1) gives crappy yeilds of nitro compounds under normal circumstances. SN2 gives good yeilds and this is consistant with the results for primary, secondary and tertiary haloalkanes.

"Nice! Could it be carried out with methyl nitrite or is it only possible if there's more than one carbon atom in the skeleton? "
No and no. If it works at all, and this is doubtful, it will be specific. In general nitrous esters cannot be rearranged to nitro compounds.

"The catalyst for substitution of -OH for -Cl is ZnCl2"
This is certainly a catalyst, but under normal circumstances the order of reaction is in the cold, tertiary alcohols react rapidly, secondary alcohols react slowly, primary alcohols dont react. This is the basis for the Lucas alcohol test. Using CaCl2 is probably a mistake, you are relying it to dehydrate things, I'm not convinced it will help. With dry HCl and enough fused ZnCl2, maybe this would produce some ethylene dichloride. Given they are making the chlorohydrin from ethylene though they could just do it in one step in the gas phase using nitrogen as a dilutant and get that directly though.

"Another method, C2H3Cl or C2H4Cl2 + CaO is much more foolproof"
Put bluntly, is this a tried and tested method (by anyone), or a guess? Ive not heard of it and dont have much of an idea if it would work or not. Assuming it works, its rather a round the houses route. There are a few easier ways to make acetylene, I would expect anyone wanting reasonable amounts to buy coke, CaO and a decent size arc welder. This method is supposed to work well.
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smile.gif posted on 17-11-2003 at 21:56
nitrous esters DO CAN be rearranged to nitro compounds


take a look @ this wonderful page:
<a href="http://www.rhodium.ws/chemistry/nitrite2nitro.html">http://www.rhodium.ws/chemistry/nitrite2nitro.html</a>
yeah Theoretic. it's possible to make your NM that way but it's just isn't the safest thing in the world to pass MeONO through hot tubes!

<blockquote>quote:<hr>.. , though not chlorides which dont work at all,<hr></blockquote>
what a pity!:(
in the same book (organicum...blah blah blah) found a reaction called (something like) finkle-estein in which the less nucleophile halogen atom in an alkyl halid is replaced with the more nucleophile halogen. a simple RX + X'<sup>-</sup> <s>&nbsp;&nbsp;&nbsp;></s> RX' + X<sup>-</sup> I don't know the exact reaction name because the persian word could be pronounced in different ways and the stupid translaters hadn't mentioned the german word.
also from vogel:
<blockquote>quote:<hr>Another test, which indicates the reactivity of the halogen atom (chlorine and
bromine), is based upon the fact that sodium chloride and sodium bromide are
sparingly soluble in pure acetone :
RCl(Br) + Nal <s>&nbsp;&nbsp;&nbsp;></s> RI + NaCl(Br)
It consists in treating a solution of sodium iodide in pure acetone with the
organic compound. The reaction is probably of the S<sub>N</sub>2 type involving a
bimolecular attack of the iodide ion upon the carbon atom carrying the chlorine
or bromine ; the order of reactivities of halides is : primary > secondary >
tertiary and Br > Cl.

Primary bromides give a precipitate of sodium bromide within 3 minutes at
25° ; chlorides react only when heated at 50° for up to 6 minutes. Secondary
and tertiary bromides must be heated at 50° for up to 6 minutes, but tertiary
chlorides do not react within this time.
1:2-Dichloro- and dibromo-compounds give a precipitate with the reagent
and also liberate free iodine :
RCHBr—CHBrR' + 2NaI <s>&nbsp;&nbsp;&nbsp;></s> RCHI—CHIR' + 2NaBr
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&uarr;&darr;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;RCH=CHR' + I<sub>2</sub>
Polybromo compounds (bromoform, <i>s</i>-tetrabromoethane) react similarly at 50°,
but simple polychloro compounds (chloroform, carbon tetrachloride and
trichloroacetic acid) do not.
Sulphonyl chlorides give an immediate precipitate and also liberate iodine :
ArSO<sub>2</sub>Cl + NaI <s>&nbsp;&nbsp;&nbsp;></s> ArSO<sub>2</sub>I + NaCl <u><sup>NaI</sup></u><s> ></s> ArSO<sub>2</sub>Na + I<sub>2</sub>
Acid chlorides and bromides, allyl halides, <font face=symbol>a</font>-halo-ketones, esters, amides and
nitriles react at 25° within 3 minutes. Vinyl and aryl halides are inert.
Prepare the <b>reagent</b> by dissolving 7 -5 g. of sodium iodide in 50 ml. of A.R.
acetone. The colourless solution gradually acquires a yellow colour. Keep
it in a dark bottle. When a red-brown colour develops, it should be discarded.
Apply the test to compounds which contain chlorine or bromine. If the
compound is a solid, dissolve 0.1 g. in the minimum volume of pure, dry
acetone. To 1 ml. of the sodium iodide-acetone reagent add 2 drops of the
compound (if a liquid) or the acetone solution (if a solid). Shake and allow
to stand at room temperature for 3 minutes. Note whether a precipitate
is formed and also whether the solution acquires a reddish-brown colour
(liberation of iodine). If no change takes place at room temperature,
place the test-tube in a beaker of water at 50°. After 5 minutes, cool to
room temperature, and observe whether a reaction has occurred.<hr></blockquote>
anyway it's lotsa work HOCH<sub>2</sub>CH<sub>2</sub>Cl <u><sup>&nbsp;NaI in acetone</sup></u><s>&nbsp;></s> HOCH<sub>2</sub>CH<sub>2</sub>I <u><sup>&nbsp;NaNO2 in DMF/DMSO</sup></u><s>&nbsp;></s> HOCH<sub>2</sub>CH<sub>2</sub>NO<sub>2</sub> + HOCH<sub>2</sub>CH<sub>2</sub>ONO
HOCH<sub>2</sub>CH<sub>2</sub>ONO <u><sup>&nbsp;heat</sup></u><s>&nbsp;></s> HOCH<sub>2</sub>CH<sub>2</sub>NO<sub>2</sub> <u><sup>&nbsp;2CH2O</sup></u><s>&nbsp;></s> (HOCH<sub>2</sub>;)<sub>3</sub>CNO<sub>2</sub> <u><sup>&nbsp;3HNO3</sup></u><s>&nbsp;></s> (O<sub>2</sub>NOCH<sub>2</sub>;)<sub>3</sub>CNO<sub>2</sub>
I prefer to oxidize ethylene chlorohydrine(let's say ECH from now) to chloroacetic acid and using it to make nitromethane ...
it's the best way of making chloroacetic acid I can think of. assuming a wide variety of oxidizers can be used and you don't worry for the level of oxidation.
I may soon try ECH using the similar standard methodes used for glycerine mono/dichlorohydrine. I mean bubblin dry HCl in HOCH<sub>2</sub>CH<sub>2</sub>OH containing acetic acid (as catalyzer)

<blockquote>quote:<hr>Lewis acids, ferric chloride and aluminium chloride notably, react with nitroalkanes to form adduct compounds.<hr></blockquote>sounds interesting, may ya give an example?

edit :<blockquote>quote:<hr>Glycol nitrite and 2-nitroethanol arnt tautomers,<hr></blockquote>you're definitely right. what a stupid mistake! it wasn't something to be mistaken, the hydrogens are in similar condition in both glycol mononitrite & 2-nitroethanol

[Edited on 18-11-2003 by KABOOOM(pyrojustforfun)]




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thumbdown.gif posted on 18-11-2003 at 05:41


""And R+ would combine rapidly and irreversibly with NO2-, right?"
This reaction mechanism (SN1) gives crappy yeilds of nitro compounds under normal circumstances. SN2 gives good yeilds and this is consistant with the results for primary, secondary and tertiary haloalkanes."
I think what you mean by that is that the carbocation combines with NO2- forming more nitrito than nitro compounds. To prevent that one needs to dispense with the carbocation-forming catalyst - AlCl3, which might be the doom of all your efforts. And the problem that it adducts with nitro compounds (the product) can be alleviated by adding more! It may even be an advantage in separating the compound (assuming it the adduct is solid), especially in the nitrito-to-nitro conversion, which I think is an equilibrium driven forward by high temperatures, so toss in excess AlCl3 and "warm the whole batch at 120°C to tautomerise the glycol nitrite to 2-nitroethanol" or else, depending on what you are preparing.
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[*] posted on 19-11-2003 at 07:35


Quote:

nitrous esters DO CAN be rearranged to nitro compounds

take a look @ this wonderful page:
http://www.rhodium.ws/chemistry/nitrite2nitro.html
yeah Theoretic. it's possible to make your NM that way but it's just isn't the safest thing in the world to pass MeONO through hot tubes!


The complete reference that page uses is P. Neogi and T. Chowdhuri, J.C.S 109, 701 (1916)

P.A.S Smith though writing 50 years later has this to say.
"Although a claim exists that alkyl nitrites may be isomerised into nitroalkanes (reference to that text and another by the same authors a year later) it has never been substantiated. On the other hand there is a large body of experimental evidence that other products are formed instead and are best accounted for by assumption that the initial step is homolytic cleavage of the RO-N bond."

The most Ive seen positive on the subject are claims that the process (pyrolysis tube at about 120C) produces mostly gas (Marvin assumes aldehyde and NO) and a very small yeild, ca 5% of a liquid (assume solution of water/aldehyde/alcohol/acid) that does test positive for the presence of a nitroalkane. But thats it. Not entirly unlike their own claim as to the products of the liquid phase reaction.

Re, Chlorides with Victor-Meyer. I wasnt quite clear. Chlorides do not work at all with silver nitrite, but they do work with sodium nitrite. Disadvantage here is most of the chlorides we'd want to use will be gasses at RTP.

Halogens will displace one another, and this can be useful. In this case however it would be just as simple to make the haloalkane directly and recycle the halide salt afterwards. In the case of ethylene chlorohydrin is quite possible a halfdecent yeild will happen directly with sodium nitrite.

Re, adducts with lewis acids. I cant find supporting information to hand. I bilieve the ferric chloride adduct with nitromethane is a bright red ppt on mixing solutions, and that the reaction of lewis acids is a general one for nitroalkanes.

Theoretic,
"I think what you mean by that is that the carbocation combines with NO2- forming more nitrito than nitro compounds"

Or forming the olefin. What would happen with stabilised primary carbocations I'm not sure, maybe more spectacular (in terms of chemistry) reactions involving the carbocation attacking the produced nitroalkane as might be expected from its bahavior in aldol like reactions.

If you are thinking of using AlCl3 to form the adduct deliberatly, you will need molar amounts, so its nolonger a catalyst, and you then need some way to remove the nitro compound out of the adduct without damaging it. I dont know how easy this would be. The idea to trap the nitrous ester-nitrocompound equilibrium on the nitro side by the use of the adduct is quite clever, but flawwed by its assumptions. The forms do not interconvert, they arnt tautomers and nitrous esters essentially cannot be converted into nitro compounds.
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KABOOOM(pyrojustforfun)
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smile.gif posted on 21-11-2003 at 20:51


Marvin! I & others owe you a BIG big thank-you. I'm not talkin about this particular thread...
anyway is tautomer of 2-nitroethanol HO-NO=CH-CH<sub>2</sub>OH ?
if so then its nitric ester may do the same ;)
NaOCH<sub>3</sub> + O<sub>2</sub>NCH<sub>2</sub>CH<sub>2</sub>ONO<sub>2</sub> <s>&nbsp;&nbsp;&nbsp;></s> NaONO=CH-CH<sub>2</sub>ONO<sub>2</sub>
2NaONO=CH-CH<sub>2</sub>ONO<sub>2</sub> + Pb(NO<sub>3</sub>;)<sub>2</sub> <s>&nbsp;&nbsp;&nbsp;></s> 2NaNO<sub>3</sub> + Pb(ONO=CH-CH<sub>2</sub>ONO<sub>2</sub>;)<sub>2</sub>
might be a pretty good primary:
Pb(ONO=CH-CH<sub>2</sub>ONO<sub>2</sub>;)<sub>2</sub> <s>&nbsp;&nbsp;&nbsp;></s> Pb + 3CO<sub>2</sub> + 3H<sub>2</sub>O + 2N<sub>2</sub> + CO




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[*] posted on 24-11-2003 at 21:46


I do it for the joy I get from helping people.

Yes, that is the aci nitro tautomer, and yes I would expect the ester to do the same - in theory. I'd be rather unhappy trying that though expecting it to work, and I might expect the attempt to hydrolyse, displace or condense somehow the ester anyway. Id be bothered what the ester portion might do if you managed to form the salt and I have no idea how stable that would be, chemically or otherwise. If a small amount forms a polymeric mess, or a dangerously sensitive salt then it was a bloody good try anyway.
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shocked.gif posted on 26-11-2003 at 01:59


MY biggest worry is the first step. It's an endothermic catalytic process, so it's hard to make it go to completion. Strong heating of course will help, but the catalyst... Do you know any more effective ones, and since the more active component is supposed to be Al2O3, is there any ways of obtaining Al2O3 in a high-surface-area, active form like SiO2 is in the silica gel?
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[*] posted on 7-1-2004 at 10:08


I take that as a "no".
BTW, this is my 250-th post. Now I'm a regular! :cool::P:D
""Another method, C2H3Cl or C2H4Cl2 + CaO is much more foolproof"
Put bluntly, is this a tried and tested method (by anyone), or a guess?"
Well, it's a based guess. Alcoholic alkali-metal hydroxides give poor yields of alkynes, alkali-metal alkoxides give a controlled reaction that can be stopped at the point of a chloralkene, while alkali-metal amides dehalogenate all they can. Since the oxide ion is of intermediate basicity between alkoxide ions and the amide ion, I assume it will work.

[Edited on 7-1-2004 by Theoretic]
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[*] posted on 7-1-2004 at 14:09


"Do you know any more effective ones, and since the more active component is supposed to be Al2O3, is there any ways of obtaining Al2O3 in a high-surface-area, active form like SiO2 is in the silica gel?"

Mr. Anonymous once posted a link to a patent for a mixture of hexamine and aluminum nitrate that could be ignited to give, it claimed, an especially active form of Al2O3.
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