sparkgap
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Olah's Nitration Book
Well, I finally got to reading a few choice sections of this book. As I mentioned in another thread, not all the syntheses described are appropriate
for the backyard/toolshed chemist, but the other reactions look quite good. The problem is that no practical methods were given; in lieu of which
however, are journal references.
A few choice sections from the book:
(italics mine)
Dedication:
"In memory of Sir Christopher Ingold, who transformed nitration chemistry into an exact science."
Industrial Use and Research Significance
Nitration has been an active area of chemistry for over half a century, This continued interest is a testimony to the importance of nitration as a
process. By far the most common industrial nitration is the sulfuric acid catalyzed nitration with nitric acid. This process is used for the
production of many large-volume chemicals such as (1) nitrobenzene, which is used as a solvent and in the manufacture of aniline; (2) dinitrobenzene,
nitrotoluenes, and nitrochlorobenzenes, which are used as intermediates for dyes, pharmaceuticals, and perfumes and (3) dinitrotoluenes, which are
converted into toluene diisocyanates for the manufacture of polyurethanes. Acid catalyzed nitrations are also used in the manufacture if high
explosives such as trinitrotoluene, glyceryl trinitrate, cellulose nitrate, cyclo-1,3,5-trimethylenetrinitramine (RDX),
cyclo-1,3,5,7-tetramethylenetetranitramine (HMX), and related nitramines…
( and that, my chemically-minded friends, is one of the joyous pursuits of mad science! )
…Ingold has pointed out some of the main reasons why aromatic nitration has been particularly useful in studying reaction mechanisms: the wide
applicability of the reactions, the fact that introduction of a nitro group into the molecule deactivates the system sufficiently so that further
nitration does not take place readily, the generally irreversible nature of the reaction, and that, under most reaction conditions, nitrations are
affected by the same reactive species: the nitronium ion…
…Continued interest in nitration is thus well justified and is a testimony to its importance in both preparative as well as mechanistic chemistry.
( yes, I know, preamble is boring, but I felt I had to set the tone for things to follow.  )
Excerpts from Chapter 2 Reagents and Methods of Aromatic Nitration:
Warning: Preparation and manipulation of nitro and particularly of polynitro compounds can potentially lead to explosions. (
emphasis mine ) Proper safety precautions are therefore essential particularly when working with acyl nitrates (or acid anhydrides plus
nitric acid), alkyl nitrates, nitramines, nitroalkanes, and their polynitro compounds. Many nitro compounds are toxic or carcinogenic ( gasp! they
are? ) and are readily absorbed through the skin.
( the nitroglycerin exposure thread comes to mind. )
I. Acid-Catalyzed Electrophilic Nitration
…Nitrating agents are of the general formula NO2-X, which serve as sources of the nitronium ion, the effective nitrating agent. Ingold termed the
NO2-X compounds “carriers of the nitronium ion”. From the ease of X-elimination, he derived a relative sequence of nitrating activity for
different nitrating agents as follows:
NO2+ > NO2+-OH2 > NO2-Cl > NO2-NO3 > NO2-O(CO)CH3 > NO2-OH > NO2-OCH3
( recognize a few of our favorites? )
However, the range of nitrating agents now is much wider. Our discussion in this chapter will review reagents and methods available for aromatic
nitration. The reactivity of the nitrating agent is also affected by the solvent used. A decreasing activity is observed in the series of solvents of
increasing nucleophilicity: H2SO4 > HNO3 > CH3NO2 > CH3COOH > 1,4-dioxan > water.
…
2.1 Nitric Acid
(chose to omit discussion for the time being)
2.2 Nitric Acid-Graphite
The intercalation of HNO3 into graphite gives “graphite nitrate” which was reported to be a nitrating and oxidizing agent under heterogeneous
conditions. Alkylbenzenes, anisole, and phenol are nitrated in moderate yield giving products with usual isomer distribution. This would indicate that
nitration is not taking place in the graphite layers but at the surface
Reference: Alazard, J. P., Kagan, H. B., Setton, R. Bull Soc. Chim. Fr. 1977, 499
2.3 Nitric-Sulfuric Acid (Mixed Acid)
(chose to omit discussion for the time being)
2.4 Nitric Acid-Oleum
Nitric acid-oleum is an extremely active nitrating agent. Its use, however, is limited to the nitration of highly deactivated aromatics since oleum
otherwise can also cause sulfonation and oxidation of more reactive aromatics. 1,3-Dinitrobenzene is nitrated to 1,3,5-trinitrobenzene at 110ºC
during prolonged heating with anhydrous HNO3 and 60% oleum in 71% yield.
2.5 Nitric-Phosphoric Acid
(chose to omit, more of theoretical interest)
2.6 Nitric-Perchloric Acid
(chose to omit discussion for the time being)
2.7 Nitric Acid-Hydrogen Fluoride
2.8 Nitric Acid-Hydrogen Fluoride-Boron Trifluoride
2.9 Nitric Acid-Boron Fluoride
2.10 Nitric-Trifluoroacetic Acid
2.11 Nitric-Methanesulfonic Acid
2.12 Nitric- Trifluoromethanesulfonic (Triflic) Acid
2.13 Nitric-Fluorosulfuric Acid
2.14 Nitric-Magic Acid
2.15 Nitric Acid-Solid Acid Catalysts
2.16 Nitric Acid-Supported Acid Catalysts
( chose to omit. not very interesting, IMHO, for our purposes. )
2.17 Monodentate Metal Nitrates
Nitrations with metal nitrates are dependent on the bonding nature of the nitrate ligand. Metal nitrates with monodentate nitrate ligands are
inactive, while those with bidentate nitrate ligands are extremely reactive and react with aromatics without catalysts.
Nitration with monodentate metal nitrates requires Lewis or Bronsted acid catalysis, because the nitrate ion requires activation to convert it into
an electrophile.
Topchiev first explored the nitration of aromatic hydrocarbons with metal nitrates in the presence of Lewis acid catalysts. They studied a number of
nitrates and found the order of reactivity to be
AgNO3 > KNO3 > NaNO3 > NH4NO3 > Pb(NO3)2 > Ba(NO3)2
The reaction is slightly exothermic, the temperature normally rising to 30-40ºC. Topchiev also studied the effect of different Lewis acids on
product yields, and found AlCl3 and BF3 to be the best catalysts for nitration.
…
…One of the main disadvantages of nitrating aromatics with metal nitrates is that the reaction is generally heterogenous. It seems that the yields
are dependent upon the nature of the Lewis acid and, to a significant extent, on the solubility of the nitrate in the reaction medium…
( rest of this section, IMHO, not very relevant to our interests )
Reference: Topchiev, A. V. Nitration of Hydrocarbons and Other Organic Compounds, Pergamon Press, New York, 1959
2.18 Alkyl Nitrates
(chose to omit discussion for the time being)
2.19 Acetone Cyanohydrin Nitrate
(chose to omit discussion for the time being)
2.20 Trimethylsilyl Nitrate
(chose to omit. not very interesting, IMHO, for our purposes.)
2.21 Acyl Nitrates
(chose to omit discussion for the time being)
2.22 Nitryl Halides
2.23 Nitrogen Oxides
2.24 Nitronium Salts
2.25 Transfer Nitrating Agents
2.26 Oxidative Nitration with Nitrosonium Salts
(chose to omit. not very interesting, IMHO, for our purposes.)
2.27 Nitration via Metallation
(I’m including only one of the more interesting sections)
2.27.1 Nitration via Mercuration
The first report of catalytic nitration via mercuration was a patent issued to Wolffenstein and Boeters at the beginning of the century. They
reported a procedure for the synthesis of dinitrophenol and picric acid via oxynitration of benzene with mercuric nitrate and 50-55% HNO3.
…
…Davis showed that mercury was the only active catalyst among many examined…
…The formation of phenolic products can be suppressed by using concentrated HNO3 instead of 50-55% acid…
...The reaction can be catalyzed by mercuric oxide, mercuric acetate, mercuric nitrate, and to a lesser extent by mercuric sulfate…
References:
Wolffenstein, R., Boeters, O. Germ. Pat. 194,883; Chem. Abstr. 1980, 2, 1861
Davis, T. L., Worrall, D. E., Drake, N. L., Heimkanys, R. W., Young, A. M.
J. Am. Chem. Soc. 1921, 43,594
Whew! That’s it for the time being…
Till then,
sparky (^_^)
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JohnWW
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I hope you can find time to scan the book to a PDF or DJVU file, and upload it to our FTP.
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BromicAcid
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| Quote: | 2.20 Trimethylsilyl Nitrate
(chose to omit. not very interesting, IMHO, for our purposes.) |
But.... but.... it's good stuff! The
journal article that I found on the subject in the Journal of Organic Chemistry stated that it produced yields of >95% on replacing the chloride on
aromatic rings with nitro groups, and claimed it was a very powerful and safe nitrating agent, expecially since it is formed under non-aqueous
conditions from chlorotrimethyl silane and silver nitrate in acetonitrile.
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Mendeleev
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Could you please post a little info on the majic acid one? In one of the acetic anhydride threads on this forum I remember someone saying it was the
most powerful nitration mixture.
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sparkgap
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Wow. Never thought this post would generate a number of replies. And I always thought a lot of people hated reading long posts.
Anyway, to address a few queries:
JohnWW: I mentioned in this post that I do not have a scanner handy, so sorry, I cannot post a scan of the book. 
BromicAcid: but.. but... TMSCl isn't available OTC! That was why I chose not to post about it. But since you asked for it, well, I'll post
as soon as I get the book back. More on this below. I do agree with your comment about TMS-NO2 being a nice nitrating agent. 
Mendeleev: since you're asking about the HNO3-magic acid combo I'll post on it too, as well as the sections I wasn't able to type in at
the start of this thread.
Since there seems to be interest in the book's contents, I will have to hunt down my pal who borrowed the book I borrowed from the library. Maybe
in two days.
Till then,
sparky (^_^)
P.S. Anyone else think I snipped off some interesting sections?
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garage chemist
chemical wizard
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I'd be interested in Acyl nitrates and in Nitryl halides.
Acetyl nitrate is interesting... I read that it is explosive and quite sensitive. I'm not so interested in its nitrating abilities, but rather
in its preparation.
Orgsyn says that Acetanhydride + HNO3 gives Tetranitromethane!
Nitryl chloride would be a very agressive substance, reacting violently with water to produce HNO3 and HCl. Similar to chlorosulfonic acid, but with
HNO3.
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sparkgap
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Continuation...
Sorry if this follow up came out late.
Well, here go the omitted and requested sections:
(italics mine)
2.1 Nitric Acid
By far the most common method for nitrating aromatic compounds is with HNO3 in the presence of acid catalysts. Nitrations can be conducted with neat
HNO3, but the presence of a strong acid accelerates the reaction.
Anhydrous HNO3, best prepared in pure form from N2O5 wih equimolar water, was shown to attain the equilibrium
2HNO3 <--> NO2+ + NO3- + H2O
Anhydrous HNO3 is an effective nitrating agent (now nitric acid would be a real bitch to dry!) Aromatic hydrocarbons as well as their
nitrated derivatives have
appreciable solubility in 100% HNO3 and nitration proceeds homogeneously. Benzene and toluene, when rapidly nitrated at 0 ºC, also give the dinitro
products with no detectable trinitro products.
...
The chief drawback of using 100% HNO3 is that its reactivity drops substantially as
water is produced during the nitration reaction. Ridd has studied the nitration of
a number of aromatic substances in aqueous HNO3 systems of strengths ranging from 64 to 100%. At lower acidities, reactive substrates such as phenol,
anisole, and mesitylene, and at higher acidities quaternary anilinium salts were nitrated efficiently. The desirability for a nitration process that
is not dependent on H2SO4 regeneration/disposal prompted several reports for nitrations with neat HNO3.
Central to the application of these nitrations is the question of regeneration of the spent HNO3. The use of N2O4 followed by air oxidation has been
suggested.
Harrar and Pearson have described a system for anodic oxidation of N2O4 in
anhydrous HNO3 to generate N2O5. When coupled with the nitration reaction, this system offers a means for nitration in anhydrous HNO3 using N2O4 as
the nitrogen source to reconvert the water that is formed into HNO3.
Nitroaromatics are soluble in concentrated HNO3 making them difficult to recover on a practical scale. Distillation is one possible approach. Carr et.
al. described a method for recoverng nitroaromatics from the spent acid by decomposing it with NO.
2HNO3 + NO --> 3NO2 + H2O
HNO3 is decomposed only to the extent necessary to cause the nitroaromatics to
separate and the off-gases are reacted with oxygen to give anhydrous HNO3.
When HNO3 is used in acetic anhydride solution, intermediate formation of acetyl
nitrate (CH3COONO2) becomes a contributor to the nitration reactions.
(CH3CO)2O + HNO3 <--> CH3COONO2 + CH3COOH
Subsequent ionization gives the nitronium ion.
CH3COONO2 <--> NO2+ + CH3COO-
Acetyl nitrate, like benzoyl nitrate and other acyl nitrates, was also prepared in
pure form and used in nitration of aromatics. Due to their instability, great care is needed when using acyl nitrates in isolated form; therefore, in
situ preparation, such as from acyl chlorides and silver nitrate, is preferred.
< omitted rest of dicussion >
References:
Schofield, K. "Aromatic Nitration", Cambridge university Press: Cambridge, 1980 and references therein.
Ridd, J.H., Draper, M.R. J. Chem Soc., Perkin II, 1981, 94
Carr, R. V. C., Zoseland, B. A., Eur. Pat. Appl. EP 169, 441; U.S. Appl. 630, 788
Harrar, J. E., Pearson, R. K. J. Electrochem. Soc. 1983, 130(1), 108-112
Carr, R. V. S., Ross, D. S., Toseland, B. A., U.S. Pat. Appl. 638, 436; Eur. Pat.
EP 173, 131;
2.3 Nitric-Sulfuric Acid (Mixed Acid)
Nitration of aromatic compounds with nitric-sulfuric acid, the so-called "mixed
acid" is the most frequently used methosd of nitration of aromatic compounds. H2SO4 aids the ionization of HNO3 to the nitronium ion, the de
facto nitrating agent, and also binds the water formed in the reaction. A convenient way of altering the nitrating activity is by changing the
concentration of the H2SO4. A number of excellent reviews are available.
< omitted rest of discussion >
References:
Schofield, K. "Aromatic Nitration", Cambridge university Press: Cambridge, 1980 and references therein.
2.6 Nitric-Perchloric Acid
Aqueous HClO4 has limited use in catalyzing HNO3 nitration. It was used in
nitrating reactive aromatics such as 1,3,5-trimethoxybenzene and
3,5-dimethoxytoluene. A disadvantage is the increasing danger of explosion
accompanying use of HClO4 in concentrations greater than 72%.
(thought so)
...
As anhydrous HNO3-HClO4 mixtures are also strong oxidizing agents for organic
compounds, they never gained wide use and extreme caution is needed. Aqueous HClO4 is also little used and still dangerous. Nitronium perchlorate
itself is a potentially explosive compound. One of the authors remembers Ingold's recollection that a sample of the isolated salt exploded
overnight causing substantial damage and ending his studies with nitronium perchlorate.
2.14 Nitric-Magic Acid
(Mendeleev's request)
The addition of antimony, tantalum, or niobium pentalfuoride to fluorosulfuric acid greatly enhances its acidity. Magic acid (FSO3H-SbF5) is one of
the strongest known superacids. Nitric-magic acid is an extremely effective nitrating agent for polynitrating aromatics.
References:
Olah, G. A., unpublished results
2.18 Alkyl Nitrates
(after rereading, I realized that exotic Lewis acids like Nafion-H were needed, and so, I will omit this section unless requested.)
2.19 Acetone Cyanohydrin Nitrate
(omitting for reasons similar to above)
2.20 Trimethylsilyl Nitrate
(BromicAcid's request)
Trimethylsilyl nitrate, (CH3)3SiONO2, is another interesting but little studied
nitrating agent. It is prepared from chlorotrimethylsilane and silver nitrate and nitrates aromatics effectively with BF3 as catalyst:
2ArH + 2(CH3)3SiONO2 -BF3-> 2ArNO2 + [(CH3)3Si]2O + BF3-H2O
Trimethylsilyl nitrate, however, even on standing readily decomposes according to
2(CH3)3SiONO2 --> 2NO2 + ½O2 + [(CH3)3Si]2O
Consequently NO2 formed can also affect nitration in the system.
References
Narang, S.C. Ph.D. Thesis, Flinders University, Adelaide, South Australia, 1975
2.21 Acyl Nitrates
Acyl nitrates, the mixed anhydrides of nitric and carboxylic acids, i.e. RCOONO2,
are reactive nitrating agents. In the isolated state, but even in solution at
temperatures above 60ºC, they can be extremely explosive (emphasis mine) and must be handled with great care. They are more
safely generated in situ. Their
preaparation can involve
(RCO)2O + N2O5 --> 2RCOONO2
RCOCl + AgNO3 --> RCOONO2 + AgCl
2.21.1 Acetyl Nitrate
Acetyl nitrate is the most widely used acyl nitrate. It is readily formed in pure
form from N2O5 in acetic anhydride. It can be distilled under reduced pressure (22 ºC @ 70 mm Hg) but decomposes explosively at 60 ºC at atmospheric
pressure.
Nitration of aromatics can be carried out in CCl4 solution. It is, however, more
convenient to prepare it in situ by addition to a solution of the aromatic and
acetyl chloride finely pulverized AgNO3.
< omitted rest of discussion >
2.21.2 Benzoyl Nitrate
Benzoyl nitrate is prepared in a manner similar to acetyl nitrate, preferentially
in situ from benzoyl chloride and silver nitrate. It has also received extensive
use in nitration, together with other aroyl nitrates.
2.21.3 Trifluoroacetyl Nitrate
(will post on request)
References:
Schofield, K. "Aromatic Nitration", Cambridge university Press: Cambridge, 1980 and references therein.
König, W. Angew. Chem. 1955, 67, 157
Houben-Weyl. "Methoden der Organischen Chemie". Vol. XII, Thieme Stuttgart, 1971, p. 757
Oxford, A. E. J. Chem. Soc. 1926, p. 2004
Kurz, M. E., Yang, L. t. A., Zahora, E. P., Adams, R. C. J. Org. Chem. 1973, 38,
2271
2.22 Nitryl Halides
The general Friedel-Crafts acylation principle can also be applied to inorganic
acid halides and anhydrides. Consequently aromatic nitrations involving nitryl halides and oxides can be considered as Friedel-Crafts type reactions.
2.22.1 Nitryl Chloride
In polar solvents at low temperatures, NO2Cl acts as a chlorinating agent for
aromatics, giving only small amounts of nitro compounds. Price and Sears first
carried out Friedel-Crafts nitration with NO2Cl and HF or AlCl3. They found AlCl3
to be the most suitable catalyst. Deactivated aromatics, however, were nitrated with difficulty, and the method was therefore considered to be of
limited value.
...
Olah and Kuhn have shown that aromatic compounds, including deactivated ones, can be nitrated with ease using nitryl halides and a suitable catalyst.
...TICl4 was found to be the most suitable catalyst...
...Sulfolane (tetramethylene sulfone) was found to be a suitable solvent for
Lewis-acid catalyzed nitrations. It has excellent solvent properties for aromatics,
many catalysts, and NO2Cl. ...
...Because sulfolane is completely niscible with water, the workup of the reaction
mixture after the reaction is comparatively easy.
< omitted rest of discussion >
2.22.2 Nitryl Bromide
2.22.3 Nitryl Fluoride
(will post on request)
References:
Collis, M. J., Gintz, F. P., Goddard, D. R., Hebdon, E. A. Chem. and Ind. 1955, p. 1742
Price, C. C., Sears, C. A. J. Am. Chem. Soc. 1953, 75, 3276
Dachlauer, K. Germ. Pat. 509,405, 1929
II. Homolytic (Radical) Nitration
(chose to omit discussion for the time being)
III. Nucleophilic Nitration
Aromatic nitration can also be carried out by nucleophilic substitution reactions.
Nucleophilic aromatic nitration, is, however, considerably less studied than
electrophilic or homolytic nitration
2.33 Nitro-Dehalogenation
Nucleophilic replacement of activated (by electron withdrawing groups) halogens in
aromatics generally shows the reactivity sequence
I > Br >> Cl
Lütgert obtained 1,2,4-trinitrobenzene by reacting 4-iodo-1,3-dinitrobenzene with
aqueous NaNO2 at room temperature. The reaction was not further investigated.
...
In aqueous solution, hydrolysis is a strong competing reaction and limits the
utility of this method. Even in nonaqueous solutions, the nitrite ion being an
ambient nucleophile tends to give aryl nitrites and, through them, phenols.
Attempted reactions with silver nitrite gave some improvement, but still generally no satisfactory yields for preparative nitration.
References:
Lütgert, H. Ber. 1937, 70, 151
Houben-Weyl. "Methoden der Organischen Chemie". Vol. XII, Thieme Stuttgart, 1971, p. 821
2.34 Nitro-Dediazoniation
(this is interesting to me)
Nitroarenes can be obtained in good yields by treatment of arenediazonium salts with sodium nitrite preferentially in the presence of Cu+ ion in
neutral or
alkaline solution. The reaction is similar to the Sandmeyer reaction:
ArN2+ + NaNO2 -- Cu2+, Cu+ --> ArNO2
Diazotization of aromatic amines followed by treatment with sodium nitrite,
generally in the presence of a copper sulfate catalyst converts arylamines into
nitroarenes. The reaction has been extensively used to prepare nitro derivatives of naphthalene inaccessible by direct nitration.
...
The replacement of the diazonium group by nirite ion can generally only be effected
in neutral or basic media. To achieve neutrality or slight alkalinity, various
methods are used: addition of CaCO3 or NaHCO3, or precipitation of the diazonium
salts as the sulfates, fluoroborates, or cobaltinitrites.
...improved yields can be obtained by the method of Ward and co-workers by adding the solution of diazonium sulfate to a solution of excess sodium
nitrite and sodium bicarbonate. If electron-withdrawing groups are present in the aromatic ring, no catalyst is needed and NaNO2 alone gives high
yields.
< omitted rest of discussion >
References:
Hodgson, H. H., Mahadevan, A. P., Ward, E. R. in "Organic Synthesis", Col. Vol. III, John Wiley and Sons:New York, 1960, p. 341
Hodgson, H. H.,Heyworth, F., Ward, E.R. J. Chem. Soc. 1948, p. 1512
Ward, E.R., Johnson, G. D., Hawkins, J. G. J. Chem. Soc. 1960 p. 894
Hodgson, H. H., Mahadevan, A. P., Ward, E. R. J. Chem. Soc. 1947, p. 1392
2.35 Nitrolysis of Diarylhalonium Ions
(chose to omit discussion for the time being)
I will be posting the sections on Aliphatic Nitration some other time.
Till then,
sparky (^_^)
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