| Pages:
1
2
3 |
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
A detailed example of the use of sulfur and chlorine in sunlight will be found in Cumming (Systematic Organic Chemistry). Here is the original example
of this, in full and in French. Note the bonus alternative production of acetyl chloride in the first example, by altering the conditions. An extreme
amount of detail, for a French article - Bull. Soc. chim. 2, 144 (1889):
Sur une nouvelle méthode de préparation du chlorure d'acétyle et de l'acide monochloracétique ; par V. AUGER et A. BÉHAL.
I. Chlorure d'acétyle. — Le tétrachlorure de soufre SCl4 réagit sur l'acide acétique d'après l'équation:
SCl4 + 2CH3COOH = SO2 + 2HCl + 2CH3COCl
Voici comment on opère:
On met dans un ballon 1 molécule de soufre ou de protochlorure de soufre, et 2 molécules d'acide acétique cristallisable. On fait passer dans le
mélange un courant de chlore en refroidissant le ballon dans un mélange de glace et de sel. Lorsque le chlore n'est plus absorbé, on laisse le
ballon revenir lentement à la température ordinaire, puis on distille avec un très bon réfrigérant et on recueille le produit dans un ballon
entouré de glace.
Il se dégage des torrents d'acide chlorhydrique et d'acide sulfureux, qui entraînent toujours une notable quantité de chlorure d'acide.
On rectifie le liquide qui distille avant 60°, puis, on le débarrasse d'un produit sulfuré, qu'il contient, en l'agitant avec du mercure, ou mieux,
avec de la poudre de cuivre. Il passe alors pur à la distillation.
Le rendement ainsi obtenu a toujours été assez faible: 500 gr. de chlorure pour 600 grammes d'acide; mais il est à penser que par l'emploi d'une
réfrigération plus énergique, telle que l'emploi de serpentins entourés de glace, on augmenterait le rendement dans de notables proportions.
II. Acide monochloracétique. — La réaction se passe tout autrement, si au lieu de faire passer le chlore à froid, on le fait passer dans le
mélange bouillant d'acide acétique et de soufre, dans les mêmes proportions que précédemment. Le produit principal de la réaction est de l'acide
monochloracétique, mélangé d'un peu de chlorure d'acétyle.
L'absorption du chlore est complète, même pour un courant de gaz assez fort; nous avons pu chlorurer 800 grammes d'acide en moins de douze heures
avec un rendement d'environ 1 kilogramme d'acide monochloré. Nous n'avons pas remarqué la formation d'acide bichloré; s'il s'en produit, ce ne peut
être qu'à l'état de traces.
Il est facile d'expliquer la chloruration si facile de l'acide en présence du chlorure de soufre. Il suffit de remarquer qu'il se forme du chlorure
d'acétyle; or, ce dernier, soit qu'il donne naissance à de l'anhydride acétique, soit qu'il se chlorure directement, facilite beaucoup de
réaction, comme on l'a, du reste, observé depuis longtemps. A la fin de la réaction, on a un mélange qui contient à la fois de l'acide
monochloré, un peu de chlorure d'acétyle, et encore moins d'anhydride acétique.
Ce procédé est beaucoup plus expéditif que tous ceux qui ont été employés jusqu'à ce jour, et le produit obtenu est d'une grande pureté, même
à la première distillation.
PS: This also works very well for bromoacetic, dibromoacetic, and alpha-bromopropionic acids:
http://books.google.com/books?id=rSvOAAAAMAAJ&pg=RA1-PA3...
http://books.google.com/books?id=rSvOAAAAMAAJ&pg=RA1-PA3...
(English abstract of both on page 5): http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo...
[Edited on 9-8-2009 by S.C. Wack]
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
Ah, zat ees veree interesting S.C, but my French is, er, how you say, a leetle non-existent. . .
You weel provide translation, no?
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
Ever heard about machine translation? -> http://babelfish.yahoo.com/translate_txt
You get the extra fun from funny translations from French terminology, like glacial=crystallizable or flask=balloon and so on.
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
http://www.rsc.org/Publishing/Journals/CA/article.asp?doi=CA...
PS: It's in there, with only a couple small details missing.
People have a hard enough time understanding my written English.
If only someone would scan a French-English dictionary for chemists and provide a permanent link to it.
[Edited on 8-8-2009 by S.C. Wack]
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
I will gladly translate this article for you guys when I have time, that is next week.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
More or less translated, based on the skills acquired during time spent with cosairs, with a few tweaks for updated terminology and others not
changed, as I'm used to and overlook them.
---------------------------------------------------------------------------
On a new method of preparation of acetyl chloride and acid Monochloroacetic; by V. AUGER et A. AUGER and A. BÉHAL. Behal.
Place in a flask 1 mole protochloride of sulfur (S2Cl2) or elemental sulfur, and 2 moles of glacial acetic acid. Pass into the mixture a stream of
chlorine, while cooling the flask in a mixture of ice and salt. When chlorine is no longer absorbed, allow the flask to slowly return to room
temperature, and then distill with very good cooling of the distillate, which should be collected in a flask surrounded by ice.
The distillation gives off torrents of hydrochloric acid (HCl gas) and sulfurous acid (SO2), which always carry away a significant amount of acid
chloride.
Collect the liquid distilling before 60 °, then it is rid of a sulfide which it contains, by shaking with mercury, or better with copper powder. It
then purified by (fractional) distilling.
The resulting yield is always fairly low: 500 gr. chloride to 600 grams of acid, but it is thought that by the use of better cooling of the
distillate, such as the use of coils surrounded by ice, would increase the performance significantly.
II. Monochloroacetic acid. - The reaction occurs quite different if instead of adding the chlorine to a cold mixture, one uses a boiling mixture of
acetic acid and sulfur in the same proportions as before. The main product of the reaction is monochloroacetic acid mixed a bit of acetyl chloride.
The absorption of chlorine is complete, even for a strong flow of gas, we have chloronated 800 grams of acid in less than twelve hours with a yield of
about 1 kg of acid monochloride. We did not observe the formation of the dichloro acid; if it is formed, it can be only in traces.
It is easy to explain chlorination of the acid chloride in the presence of sulfur. It suffices to note that forms acetyl chloride, the latter gives
rise to acetic anhydride, chloride or where it directly facilitates further reaction (to chloroacetic ) as has, moreover, observed long ago. At the
end of the reaction, we have a mixture that contains both the monochloro acid, a bit of acetyl chloride, and even less of acetic anhydride.
This process is much more expeditious than those who have been employed to date, and the resultant product is of high purity, even in the first
distillation.
|
|
|
turd
National Hazard
Posts: 800
Registered: 5-3-2006
Member Is Offline
Mood: No Mood
|
|
What I like most is that you add to your flask one molecule of sulfur and two molecules of acetic acid. Though I realize that's not necessarily the
French, but the chemistry lingo of that time...
|
|
|
Sciocrat
Harmless
Posts: 36
Registered: 30-3-2007
Member Is Offline
Mood: Scientifically curious
|
|
Quote: Originally posted by Polverone  | I was able to retrieve the requested article on microfilm. Here's most of the article:
| Quote: | The production of ethyl chloroacetate, and eventually of choroacetic acid, by the action of water on aB (these should be alpha and beta, but I
don't recall how to make greek symbols)-dichlorovinyl ethyl ether has been the subject of a large number of patents. By using dry hydrogen
chloride in place of water, chloroacetyl chloride is obtained (<A
HREF="http://l2.espacenet.com/espacenet/bnsviewer?CY=ch&LG=en&DB=EPD&PN=DE222194&ID=DE++++222194A++I+">DE222194</A> , and Imbert found (<A
HREF="http://l2.espacenet.com/espacenet/bnsviewer?CY=ch&LG=en&DB=EPD&PN=DE212592&ID=DE++++212592A++I+">DE212592</A> that dichlorovinyl ethyl ether and ethyl alcohol react, with the production of ethyl
chloroacetate and ethyl chloride.
We find that aB-dichlorovinyl ether enters into a large number of reactions of the above type. It is attacked, and usually with great readiness, when
heated with alcohols, phenols, or acids. Action is of two kinds:
CHCl:CCl-OEt + ROH ->
1) CH<sub>2</sub>Cl-CO<sub>2</sub>R + EtCl
2) CH<sub>2</sub>Cl-CO<sub>2</sub>Et + RCl
and it seems likely that an additive compounnd, CH<sub>2</sub>Cl-CCl(OEt)-OR, is first formed, which decomposes into the products 1 and 2.
Our experience is that alcohols give the products of both reactions, but that 1 predominates, except in the case of methyl alcohol. Phenols give the
products of 1 only, and usually in excellent yield. Acids react mainly in accordance with 2, the products being ethyl chloroacetate and an acid
chloride. The yields are variable, but it would appear that reactions of the above type could be used in certain cases for the production of
chloroacetates or acid chlorides.
To prepare aB-dichlorovinyl ether, sodium is dissolved in dry alcohol in sufficient quantity to form a saturated solution of sodium ethoxide.
Trichloroethylene is then added in the proportion of one molecule of trichloroethylene to one and a half atoms of sodium. Heat is applied until action
commences, when further heating is unnecessary. The product, when cold, is mixed with a large volume of distilled water, and the oil which separates
is washed, dried with calcium chloride, and rectified. The main portion distills at 122-126 degrees C, and this is nearly pure dichlorovinyl ethyl
ether. The yield is about 70 percent of the theoretical.
For the action on alcohols or phenols, the substance was employed in as dry a state as possible and mixed with the ether in equivalent quantity. Heat
was applied to start the reaction, but further heating was often unnecessary, except toward the end of the process. In other cases, however, head had
to be applied throughout to maintain the reaction. The products were separated by fractional distillation, or, where possible, by crystallization.
The results with methyl alcohol were not in accordance with Imbert's statement. Ethyl chloroacetate was the main product and methyl chloroacetate was
only produced in relatively small quantity. Ethyl alcohol gave the expected excellent yield of ethyl chloroacetate. iso-Amyl, heptyl, allyl, and
menthyl alcohols were each found to yield the chloroacetate of the acid radicle, but ethyl chloroacetate was also formed in these cases.
All the phenols examined gave good yields of the aryl chloroacetate, but in no case was ethyl chloroacetate detected. The compounds dealt with were
phenol, o-cresol, guaiacol, alpha and beta-naphthol, resorcinol, and quinol. The two latter compounds gave the bischloroacetates.
The monobasic acids, the behavior of which with dichlorovinyl ethyl ether was examined, were acetic, chloroacetic, phenylacetic, benzoic, anisic, and
alpha-naphthoic. In most cases action occurred readily on heating, but it was necessary to apply heat continuously throughout the process. Some
hydrogen chloride was evolved in each case, but ethyl chloride was only observed in the case of anisic acid and of naphthoic acid. Ethyl chloroacetate
was always present as the chief product of the reaction. The acid chloride formed at the same time was isolated in a pure state in the reactions with
acetic, chloroacetic, and benzoic acids. In the other cases, the acid chloride was not obtained pure, but its presence was indicated by the immediate
production of the corresponding amide on treating the appropriate fraction with ammonia. |
Oooh, making acetyl chloride and ethyl chloroacetate - what interesting products to obtain from a cheap solvent chemical! Now if only sodium ethoxide
were a little easier for an amateur of limited means to prepare in a clean and concentrated state. |
So, if I got that correctly, in order to synthesize ethyl chloroacetate, one can also react dichlorovinyl ether with water? Wouldn't the produced
ethyl chloroacetate react further with water?
|
|
|
leu
Hazard to Others
Posts: 368
Registered: 13-10-2005
Member Is Offline
Mood: No Mood
|
|
Chloroacetic acid can be made from glycine as is described in the following patents, DE348671 and FR663236:
Attachment: DE348671C.pdf (130kB)
This file has been downloaded 869 times
Attachment: FR663236A.pdf (220kB)
This file has been downloaded 818 times
Chemistry is our Covalent Bond
|
|
|
leu
Hazard to Others
Posts: 368
Registered: 13-10-2005
Member Is Offline
Mood: No Mood
|
|
Ethyl chloroacetate is generally made from chloroacetic acid, ethanol and sulfuric acid as in Ann 188 218 (1877) by Conrad
or HCl gas JCS 65 423 (1894) by Perkin; Conrad's method is in Organic Syntheses 14 38-9 (1934)
Note 2 or Organic Syntheses Colective Volume 2 262-3 (1943)  The
hydrolysis of ethyl chloroacetate has been studied in the attached articles; JCS 876-83 (1937) and JCS 862-9 (1938) 
Attachment: JR9370000876.pdf (229kB)
This file has been downloaded 831 times
Attachment: JR9380000862.pdf (170kB)
This file has been downloaded 3533 times
[Edited on 24-6-2010 by leu]
Chemistry is our Covalent Bond
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Nick | Is making this as simple as bubbling chlorine through acetic acid?
Does anyone know of an exact synthesis for it? |
A no longer used industrial method - trichloroethylene and sulpuric
acid. Yields 50% pure CA-A and a lot of HCl. See Ullmann
for details.
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
|
|
Trichloroethylene is not readily available to the home chemist and of limited availability to the professional chemist.
Cost and availability of chlorinated solvents has moved them on to the use if there is no alternative list! :-(
|
|
|
mnick12
Hazard to Others
Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline
Mood: devious
|
|
ScienceSquirrel, I happen to have about 800ml of trichloroethylene that I bought from a supplier. I will go ahead and send you the link through a pm,
and they also ship to individuals.
|
|
|
leu
Hazard to Others
Posts: 368
Registered: 13-10-2005
Member Is Offline
Mood: No Mood
|
|
| Quote: | | See Ullmann for details. |
The Institute lists these patents:
US1304108
US1322898
DE359910
DE383029
FR602395
FR705905
FR774172
as far as getting chloroacetic acid from polychloroethyl compounds using acid catalysis
Attachment: US1304108A.pdf (154kB)
This file has been downloaded 763 times
Attachment: US1322898A.pdf (216kB)
This file has been downloaded 676 times
Attachment: DE359910C.pdf (230kB)
This file has been downloaded 675 times
Attachment: DE383029C.pdf (186kB)
This file has been downloaded 680 times
Attachment: FR602395A.pdf (142kB)
This file has been downloaded 679 times
Attachment: FR705905A.pdf (74kB)
This file has been downloaded 648 times
Attachment: FR774172A.pdf (119kB)
This file has been downloaded 668 times
[Edited on 25-6-2010 by leu]
Chemistry is our Covalent Bond
|
|
|
mnick12
Hazard to Others
Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline
Mood: devious
|
|
I will have to try this some time, as I have a lot of trichloroethylene and would like some chloroacetic acid for trying a reformatski reaction. I
have a question though, why is conc
H2SO4 used rather than dilute?
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by mnick12 | I will have to try this some time, as I have a lot of trichloroethylene and would like some chloroacetic acid for trying a reformatski reaction. I
have a question though, why is conc
H2SO4 used rather than dilute? |
In never suggested conc. H2SO4. I had hoped you would have
check the ref. provided.... yeasure.
This from Ullmann
Equal amounts of TCE and 75% sulfuric acid are reacted at
130-140o C in a continuous process so that with complete TCE
conversion, the resultant reaction mixture contains about
50% chloroacetic acid and 1-2% water. This blend is vacuum
distilled to give pure CA
TCE (1500-1850 kg) and H2SO4 (600 kg 95%) gives 1000 kg
of finished product and 700-750 kg of HCl gas as a byproduct.
An advantage of this process is that little if any di- and tri- CA
is produced.
|
|
|
mnick12
Hazard to Others
Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline
Mood: devious
|
|
*Sigh* I was not referring to your post The Wizard Is In, I was referring to one of the attachments leu kindly posted. Maybe I should be a little more
clear when I am writing but that one seemed rather clear to me. Oh well. Sorry for the confusion.
|
|
|
The WiZard is In
International Hazard
Posts: 1617
Registered: 3-4-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by ScienceSquirrel | Trichloroethylene is not readily available to the home chemist and of limited availability to the professional chemist.
Cost and availability of chlorinated solvents has moved them on to the use if there is no alternative list! :-( |
Howbout - Plan B.
This from :—
Faith, Keyes, and Clarks Industrial Chemicals. 4th ed.
In a typical batch process, 160 kg of glacial acetic acid (75o C)
and 4.5 to 6.3 kg of red phosphorus in 6.8 kg of acetic acid
are charged to a jacketed chlorinator. Here chlorine is brought
into contact with the liquid by means of a distributor plate. The
chlorine is fed at a rate of 9 kg/h for the first hour; the rate is
gradually increased to 27 kg/hr after the first hour. Reaction
temperature is held to 95 to 105o C by cooling. At the end
of 8 h, the reaction mass is discharged to a crystallizer for
recovery of the crystalline product. During the chlorination,
hydrogen chloride is evolved and directed to a scrubber for acid
recovery.
The mother liquor from the crystallization process contains both
acetic acid and CA, as well as monochloroacetic acid. The mixture
maybe further chlorinated to trichloroacetic acid. At on time
the TCA was hydrolyzed with milk of lime to produce chloroform.
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination!
|
|
| Quote: Originally posted by mnick12 | | ScienceSquirrel, I happen to have about 800ml of trichloroethylene that I bought from a supplier. I will go ahead and send you the link through a pm,
and they also ship to individuals. |
Not much use to me as they are in Utah and I am in Jersey, Channel Islands.
I should not have generalised. one person's unobtanium is easily bought in another jurisdiction.
|
|
|
mnick12
Hazard to Others
Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline
Mood: devious
|
|
Huh thats odd, will they not ship to you?
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
I beg to differ. In some countries trichloroethylene is the most common halogenated solvent available OTC. For example, it is the only one I can buy
in its pure form by just visiting a hardware store, while dichloromethane, for example, is available only in paintstrip mixtures. Sure, I was able to
buy dichloromethane in a hardware shop by asking the clerk to order it for me, but trichloroethylene is right there on the shelves (and last time I
checked it was still there). It was also the most common degreaser solvent used in the local industry and mechanics workshop ("it was" because the
information I have about this is a few years old, maybe meanwhile the EU regulations changed the status of this solvent).
BTW, trichloroethylene was the first organic solvent that came into my possession when I was a kid. I only later found out that toluene is sold in
hardware shops.
| Quote: Originally posted by mnick12 | | *Sigh* I was not referring to your post The Wizard Is In, I was referring to one of the attachments leu kindly posted. Maybe I should be a little more
clear when I am writing but that one seemed rather clear to me. Oh well. Sorry for the confusion. |
And just where do you think the references to those patents came from? You were indeed indirectly referring to his post. Anyway, unless you have a
corrosion resistant autoclave, you will have to build some pretty sophisticated glassware for this reaction to be run at normal atmospheric pressure
as merely refluxing a mixture of H2SO4 and trichloroethylene does nothing, at least not in my experience. The temperature of reflux is way too low for
the reaction (bp of TCE is 87°C, compare that to the required >130°C). I'm not saying that you can not build the required apparatus that would
allow for a slow dripping of TCE on H2SO4 heated at the right temperature and recycling the vapours, just that it is not something trivial.
…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!
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination!
|
|
I am not really in the EU.
Jersey, Channel Islands is a semi detached part of the UK with an associate relationship to the EU and it has it's own shipping and transportation
rules plus its own version of purchase tax called GST.
The island has it's own Customs & Excise Service.
In really complicated high value orders I have to claim back the VAT from the UK supplier but pay GST before the goods are released to me.
I can buy THF by the litre with no problems but diethyl ether is difficult due to shipping issues.
I cannot buy trichloroethylene over the counter or from my usual suppliers but I can buy sodium borohydride or iodine by the kilogram with no problems
from out of island suppliers.
Note to Nicodem: We do not have hardware stores staffed by clerks, this is a US phenomenon!
|
|
|
Anders Hoveland
Banned
Posts: 208
Registered: 15-6-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by madscientist | Whoops! I forgot about this! The NO2 group resonates between the nitro and the nitrite structure! Therefore using a nitrite for nucleophilic
substitution on a organic compound *would* work.  |
I think you are misinformed. I have read that carefully heating organic nitrites can turn a percentage of them into nitro groups, though.
http://pubs.acs.org/doi/abs/10.1021/ja01641a029
By heating an alkyl halide with aqueous alcoholic solution of silver nitrite
C2H5Br + AgNO2 —> C2H5NO2 + AgBr
Some quantity of alkyl nitrite is also formed in this reaction. It can be removed by fractional distillation since alkyl nitrites have
much lower boiling points as compared to nitro alkanes.
(b) By the direct nitration of paraffins (Vapor phase nitration)
................................................400C
....CH3CH3 + HONO2 (fuming) ——> CH3CH2NO2 + H2O
With higher alkanes, a mixture of different nitro alkanes is formed which can be separated by fractional distillation.
(c) By the action of sodium nitrite on α-halo carboxylic acids
...................................................NaNO2 heat
ClCH2COOH —> NO2CH2COOH —> CH3NO2 + CO2
α-chloro acetic –NaCl α-Nitroacetic acid
http://www.transtutors.com/chemistry-homework-help/nitrogen-...
[Edited on 6-7-2010 by Anders Hoveland]
|
|
|
Anders Hoveland
Banned
Posts: 208
Registered: 15-6-2010
Member Is Offline
Mood: No Mood
|
|
Under very acidic conditions, acetic acid should be able to react with chlorine at room temperature.
CH3--C(O)(OH) <---> CH2==C(OH)2
The hydrogens on the alkene then get attacked.
CH2==C(OH)2 + Cl2 --> Cl--CH==C(OH)2 + HCl
Or you can use chlorine left in sunlight with white vinegar. Because of the radical cascade, one photon will effect a reaction on several molecules.
Chloroacetic acid is quite poisonous if ingested.
"enol-keto tautomerization; initial product from the addition of water to an alkyne is an enol (a compound having a hydroxyl substituent attached to a
double-bond), and this immediately rearranges to the more stable keto tautomer." http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/addy...
|
|
|
Anders Hoveland
Banned
Posts: 208
Registered: 15-6-2010
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by Polverone | | What a silly question. A couple minutes with Google answered it for me. All I need to do is react an alkali nitrite with alkyl halide in DMSO. No
problem. Yay! Now if I only had some distillation equipment I could start cranking out the nitromethane... |
I cannot find the reference, but as the number of substitutions on the molecule grow, the yield falls considerably. (like if BrCH2CH2Br were used) A
tertiary nitro compound made from the procedure above, would only give a yield of 11% if I remember correctly. I believe the problem was the organic
nitrites are a competing product.
| Quote: Originally posted by PHILOU Zrealone |
ClCH2-CO2H + AgNO2 --> O2N-CH2-CO2H + AgCl
alfa nitroacids readily decarboxylate upon water boiling what also iomerises the nitrite ester into the nitrocompound!
O2N-CH2-CO2H --> CH3-NO2 + CO2
ONO-CH2-CO2H --> O2N-CH2-CO2H
PH Z |
I believe that I have read that only an organic bromide or iodide will substitute out, chloromethane would not be expected to react with silver
nitrite. The reason probably has to do with the biger atomic radius, allowing it to serve as an electron receptor, despite already being bonded. Of
course, chloroacetic acid will react with nitrite because it is being heated and intermediate radicals form.
[Edited on 6-7-2010 by Anders Hoveland]
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
