garage chemist
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benzotrichloride---> benzoylchloride
In a chemistry book, I read that the hydrolysis of benzotrichloride (which normally produces benzoic acid) can be stopped at benzoyl chloride. No
condidtions and no literature were stated.
Benzoyl chloride is useful because it is a reactive acid chloride and can exchange its chlorine atom with the hydroxyl of another carboxylic acid.
For example, acetyl chloride can be distilled in high yield from a mixture of benzoyl chloride and GAA.
Does anyone know about the reaction conditions for the partial hydrolysis of benzotrichloride? Google turned up nothing useful.
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trilobite
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The following material should answer your questions and more.
Benzoyl chloride.
George, A.
US1557154
Abstract
H2O is gradually added to an agitated mixture of PhCCl3 containing a catalyst such as ZnCl2 or other Zn compound in suspension and maintained at a
temperature (which may be about 100-120 Deg) at which active hydrolysis takes place. Not more than 10% in excess of the theoretically required H2O
(to form benzoyl chloride) is used.
Halides such as benzoyl chloride and acetyl chloride.
Mills, Lindley E. (Dow Chemical Co.).
US1965556
Abstract
A benzoyl trihalide such as benzoyl trichloride is caused to react with an organic carboxylic acid such as HOAc in the presence of an acid catalyst
such as H2SO4, H3PO4 or perchloric acid.
Aromatic acid chlorides.
Bennett, Nicholas; Dodd, Herbert; Sprent, William C. (Imperial Chemical Industries Ltd.).
US1880169
Abstract
Aromatic monocarboxylic acid chlorides such as benzoyl chloride are produced by the reaction of a chloride of the benzene series such as benzal
chloride with an aromatic acid or aromatic acid anhydride such as benzoic acid or anhydride, followed by chlorination of the reaction mixture.
Aromatic acid chlorides; ethyl chloride.
(Verein fur chemische und metallurgische Produktion).
DE472422
Abstract
The reaction between EtOH and PhCCl3 is effected in the presence of Fe or FeCl3, whereby EtCl and PhCOCl uncontaminated with PhCOOEt are obtained.
Homologs or substitution products of PhCCl3 may be treated in the same way.
Purifying organic acid chlorides.
Luthy, Max; Thomas, Benjamin E. (Monsanto Chemical Works).
US1906761
Abstract
Impurities are removed from org. acid chlorides such as o- and p-toluenesulfonyl chlorides or AcCl or benzoyl or phthalyl chlorides by treatment with
an inorg. basic material such as CaO or MgO.
Convenient preparation of volatile acid chlorides.
Brown, Herbert C.
Journal of the American Chemical Society, 60, 1325-8 (1938)
Abstract
Volatile acid chlorides may be prepared by heating a mixture of 2 parts BzCl and 1 part acid; a ratio of 3:2 gives slightly lower yields, while the
yields with 1:1 ratio are much lower; bubbling a slow stream of dry HCl through the reaction does not materially increase the yield. Distillation of
the acid chloride should be at such a rate that the temperature at the top of the column does not exceed the b. p. of the chloride. In
refractionating the distillate care should be taken to maintain a very high reflux ratio at first, otherwise the dissolved HCl tends to carry over a
considerable amt. of the acid chloride below its true b. p. Using a ratio of 2 BzCl to 1 of acid, the following yields were obtained (%): AcCl 85,
ClCH2COCl 76, Cl2CHCOCl 73, Cl3CCOCl 56, EtCOCl 89, PrCOCl 87, iso-PrCOCl 88, BuCOCl 84, iso-BuCOCl 84, Me3CCOCl 92, AmCOCl 80, crotonyl chloride 80.
The mechanism of the reaction is discussed but no definite conclusion was reached concerning it.
Simultaneous synthesis of aromatic acid chlorides and metal chlorides.
Schreyer, R. C.
Journal of the American Chemical Society, 80, 3483-4 (1958)
Abstract
A new simultaneous synthesis of aromatic acid chlorides and metal chlorides from trichloromethylated aromatic compds. and metal oxides is reported.
The method consists of heating the reactants in the following proportions: (CCl3)2C6H4 + TiO2 -> (ClOC)2C6H4 + TiCl4; 3/2 (CCl3)2C6H4 + V2O5 ->
3/2 (ClOC)2C6H4 + 2VOCl3; 5PhCCl3 + V2O5 -> BzCl + 2VCl4 + Cl2. TiO2 and V2O5 give the best yields of both acid and metal chloride; oxides of As,
Sb, and Zr give lower yields. A stoichiometric mixt. of the reactants is heated to 200-300 Deg. The volatile metal chloride or oxychloride is distd.
from the mixt. and vacuum distn. of the residue gives the acid chloride in excellent yield, e.g., 313 g. m-(CCl3)2C6H4 and 82 g. TiO4 heated rapidly
to 270 Deg yielded 85% m-(ClOC)2C6H4, m. 39-40 Deg, and 95% TiCl4, b. 135-6 Deg.
Then there is the patent DE11494 from the year 1879. I shall give an approximate translation of the different possibilities this late German chemist
has to offer, in English. Maybe someone better at German could point out if there are any errors.
Inventions for Preparation of Benzoic Acid, Ethyl Benzoate and Benzaldehyde Along with Organic Acid Chlorides, Acid Anhydrides from Benzotrichloride
or Dichloride in Presence of Metal Salts.
Dr. Emil Jacobsen
I. Benzotrichloride is added to a mixture of two equivalents of glacial acetic acid and a few percents of ZnCl2 heated on a water bath. HCl is
evolved at a rate governed by the addition while acetylchloride distills over and is collected. The still residue consists of benzoic acid, ZnCl2 and
condensation products originating from the impurities in technical benzotrichloride.
The reaction equation:
1) C6H5-CCl3 + 2AcOH --> C6H5-COOH + 2AcCl + HCl
Benzoic acid and acetyl chloride are produced also with reverse addition or mixing the reagents together and distilling. If acetic acid containing
water is employed it is best to add the acetic acid to the benzotrichloride.
The mixture is further heated until the evolution of hydrochloric acid and acetyl chloride ceases and most of the acetic acid, either excess or
produced from hydrolysis of acetyl chloride by water present, is removed.
On cooling down the brownish black molten still residue freezes to a crude crystalline mass, which is then powdered and dissolved in warm solution of
sodium carbonate. Pure (well, maybe after cleaning a bit, depending on your benzotrichloride of course) benzoic acid is precipitated by acids.
II. The evolution of hydrochloric acid can be avoided if half of the acetic acid used is replaced by equivalent amount of anhydrous zinc acetate.
III. Acetic anhydride is produced if the acetic acid is replaced completely by anhydrous zinc acetate. However, the great amount of zinc chloride
produced makes reaction too vigorous. Also in this case the reaction product is benzoic acetic anhydride which reacts further to benzoic acid.
It is advantageously possible to replace the catalytic amount of zinc chloride with anhydrous zinc acetate, as it is more resistant to
air.(humidity I suppose)
IV. Using aqueous acetic acid in a process as described above will give anhydrous acetic acid as one product, if the amount of water is less than
needed for complete hydrolysis of the acetyl chloride.
V. Benzotrichloride can be converted to benzoic acid alone by warming benzotrichloride with some acetic acid and zinc chloride or acetate under reflux
condenser, and adding exactly the amount of water needed for hydrolysis. Most of the acetic acid can be recovered. Also other carboxylic acids can be
used for this purpose, such as formic acid or anhydrous oxalic acid which gives a slower reaction.
Benzoic acid reacts quantitatively to benzoyl chloride by the following equation:
2) C6H5-CCl3 + C6H5-COOH --> 2C6H5-COCl + HCl
This side reaction also occurs in the reaction of acetic acid with benzotrichloride in the presence of zinc chloride. Small amounts of benzoyl
chloride can be found among the distilled acetyl chloride.
VI. If benzodichloride is treated with acetic acid and zinc chloride under the same conditions, benzaldehyde, acetyl chloride and hydrogen chloride
are produced.
3) C6H5-CHCl2 + AcOH --> C6H5-CHO + AcCl + HCl
The modifications described in II, III, IV and V are also possible with this reaction. Benzodichloride reacts analogously to benzotrichloride, but
giving benzaldehyde.
Benzaldehyde condenses with benzotrichloride in the presence of zinc chloride, thus benzoic acid containing little benzodichloride and no odor of
bitter almond oil is produced by use of acetic acid as in I.
VII. Carboxylic acid esters react with benzotrichloride and dichloride in a similar way. Ethyl acetate gives ethyl benzoate or benzaldehyde and
ethyl chloride.
4) C6H5-CCl3 + 2AcOEt --> C6H5-COOEt + 2AcCl + EtCl
5) C6H5-CHCl2 + AcOEt --> C6H5-CHO + AcCl + EtCl
Also in this case benzoyl chloride is produced.
VIII. Reacting aliphatic alcohol such as ethyl alcohol with benzotrichloride and zinc chloride as in I gives ethyl benzoate, ethyl chloride and
hydrogen chloride, excess ethanol increasing the yield of ethyl chloride and decreasing that of hydrogen chloride. Benzoyl chloride is produced here
too.
The reaction equation:
6) C6H5-CHCl2 + EtOH --> C6H5-CHO + EtCl + HCl
IX. Salts of certain other metals could also be used in the reaction, such as antimony chloride and cupric chloride, the latter performing worse.
The zinc salts are particularly useful for the purpose.
Benzyl bromides could be used in the place of chloride.
The mention of using formic acid or anhydrous oxalic acid most likely isn't related to producing the corresponding acid chlorides. Formyl
chloride is stable only at very low temperatures, decomposing to carbon monoxide and hydrogen chloride, while oxalic acid is prone to decomposition to
formic acid and carbon dioxide, oxalyl chloride isn't too stable either.
[Edited on 23-5-2005 by trilobite]
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quest
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sorry if this a little of topic...
Is there any way to make benzaldehyde from benzoic acid?
I know benzaldehyde can be oxidized to benzoic acid, but is there any reversal reaction?
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garage chemist
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That's fantastic! Benzotrichloride directly used as a chlorination agent to produce acetyl chloride- simply amazing.
And using benzodichloride, which is even simpler to produce, yields the valuable benzaldehyde (instead of benzoic acid) as a side product.
Now it pays off to have invested into one liter of GAA when I had acess to it.
I knew that it would somehow be possible to produce acyl chlorides without the use of phosphorus trichloride or thionyl chloride.
Thanks a lot, trilobite!
@ quest: Yes, but only with excessive effort. You'd have to reduce the acid to the alcohol with LiAlH4 and then reoxidise it to the aldehyde with
MnO2/H2SO4. This would be a horrible waste of an expensive chemical.
If you want benzaldehyde, buy some benzyl alcohol (non- regulated and non- watched, perhaps from Ebay?) and oxidise it with MnO2/H2SO4.
Or, more OTC, get some toluene, chlorinate it to benzal chloride and react it with GAA. This gives acetyl chloride as a "side product" which
can be used to make acetic anhydride.
Or react the benzal chloride with ethanol, this gives chloroethane as a side product, which can be condensed with salt/ice (bp 11°C!) and used for
the preparation of nitroethane.
So many possibilities!
[Edited on 23-5-2005 by garage chemist]
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chemoleo
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Very interesting.
Whats the route for making PhCCl3 in the first place? Direct chlorination of toluene?
Mmmh I can see a route to acetic anhydride here!
[Edited on 23-5-2005 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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garage chemist
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Yes, the easy production of PhCCl3 from toluene and chlorine (chlorine passed into refluxing toluene until a certain boiling point is reached) is the
interesting thing here.
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trilobite
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I haven't got any practical experience on chlorinating toluene, but from what I have read I know that the absorption of chlorine to the reaction
mixture slows down markedly when the amount of benzotrichloride starts to rise even with UV illumination. Cascading multiple chlorination vessels in
series is the key for good usage of chlorine gas, the degree of chlorination being always highest in the first vessel. But I think Org has already
told about this. This is why the possibility to use benzal chloride is such a good thing. It'd be interesting to know if a mixture of GAA, fused
sodium acetate and ZnCl2 would give acetic anhydride, avoiding the need to react acetyl chloride with sodium acetate seaparately. There are some cases
where you want to have acetic acid as the byproduct in acetylation and not hydrogen chloride.
If it is benzoyl chloride you want, chlorinating benzaldehyde will get you there as told in those patents as well as Organic Syntheses (gotta love
it).
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1...
There is an old and detailed article on the operation of an industrial plant producing benzoic acid, benzaldehyde and benzyl alcohol through the
chlorination of toluene titled Fine chemicals from coal published in Journal of Industrial and Engineering Chemistry, 41, 1812-20 (1949).
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garage chemist
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When I was chlorinating toluene, the chlorine was completely absorbed. Nothing was coming out of the condensor. I was only producing benzylchloride,
though. And I used a 500W floodlight to illuminate the reaction. I also used 1,4% Red Phosphorus as an additional sidechain chlorination catalyst
(although this wasn't necessary at all and most likely only consumed some more chlorine).
You're right, the use of benzal chloride has two advantages: first, the easier production and second the formation of benzaldehyde as a
side-product.
One of my next projects will be the production of benzal chloride, which shouldn't be too difficult either.
The I will conduct the following reaction:
PhCHCl2 + AcOH ---(ZnCl2)---> PhCHO + AcCl + HCl
Or this one:
PhCHCl2 + EtOH ---(ZnCl2)---> PhCHO + EtCl + HCl
This one combines the two and evolves no HCl:
PhCHCl2 + EtOAc ---(ZnCl2)---> PhCHO + AcCl + EtCl
EDIT: Reaction Nr. 5 in the green text is wrong. There are three chlorine atoms on the right side and two on the left side.
[Edited on 23-5-2005 by garage chemist]
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trilobite
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Thanks. I fixed the typo.
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Organikum
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| Quote: |
I know benzaldehyde can be oxidized to benzoic acid, but is there any reversal reaction?
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Benzoic acid and carbon black are pressed into a electrode and elctrolysed with H2SO4 saturated with
benzoic acid as electrolyte and lead as the other electrode. Benzaldehyde separates on top.
From an old german patent I found some time ago.
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Organikum
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bala
bala
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Mephisto
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In this context, I think it's appropriate to name the SOMMELET reaction, which is good for the preparation of aldehydes from aralkyl halides by
treatment with hexamethylenetetramine. For instance benzaldehyde from benzylidene chloride, which can be made by chlorination of toluene.
<center> </center>
Maybe this way is an improvement only for substituted analogues in comparison to better known methods.
References (TheMerckIndex) / mechanism (with a description in German).
~Mephisto
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