benzylchloride1
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Synthesis of 3-Nitrophthalic Acid; Luminol Precursor
3-nitrophthalic acid has been synthesized by several different methods; nitration of phthalic anhydride and the oxidation of nitronaphthalene. An
attempt was made at the oxidation of nitronaphthalene with dichromic acid, but only a tar was isolated. Alkaline permanganate oxidations does not
produce the desired product. Nitration of phthalic anhydride gives low yields of easily isolated product of high purity. The method in Vogels textbook
requires fuming nitric acid and large quantities of 70% nitric acid and only give a yield of 25%. The niration by this method is reported to procede
with explosive violence The procedure used in this experiment was adapted from E.R.Litmann, The Preparation of 3-Nitrophthalic Acid, 1925, Journal of
the American Chemical Society. This method claims to give 85-90% yields of 3-nitrophthalic acid. A 1/10th scale procedure was conducted, producing
3-nitrophthalic acid in a yield of 20%. The product melted at 216 C, 2 degrees below the literature value of 218 C, obtained from the CRC Handbook of
Organic Compound Identification.
Experimental:
Chemicals Needed:
18.5g of Phthalic anhydride
17.5ml Nitric Acid, 70%
17.5ml of sulfuric Acid, 92%
The phthalic anhydride that I purchased off of Ebay was mainly phthalic acid and melted above 200 C. The product was heated to drive off the water and
then distilled, collecting the phthalic anhydride. 18.5g of phthalic anhydride was added to 17.5ml of nitric acid in a 250ml round bottomed flask.
17.5ml of sulfuric acid was added slowly with swirling. A reflux condenser was attached and the mixture was heated in a boiling water bath for 2
hours. The phthalic anhydride dissolved and nitrogen oxides were generated in small quantity. After about an hour, crystals had formed in the mixture.
After 2 hours the mixture was cooled to room temperature and poured into 50ml of cold water with stirring. The product was filtered off with a fritted
funnel. The product was washed with 30ml of cold water. The reaction mixture after sitting in an ice bath for several hours, deposited more crystals
which were then filtered in the same manner and washed with a small amount of water. The crude product was recrystallized from a small amount of
water. The solution of 3-nitrophthalic acid must sit for several days for crystallization to occur. The product is then filtered and the solution
concentrated to 1/4 the volume to obtain a second crop. 5.23g of product was obtained with a percentage yield of 20%. The product melted at 216 C.
3-nitrophthalic acid is very soluble in water, and much product remained in the reaction mixture.
[Edited on 17-6-2009 by benzylchloride1]
[Edited on 17-6-2009 by benzylchloride1]
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Ozonelabs
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Ozonelabs will be conducting a synthesis of this compound with the fuming acids in an attempt to better currently obtained yields- this is part of an
ongoing Luminol project.
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Magpie
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Nice going benzylchloride1!
Do you think your yield can be improved?
The single most important condition for a successful synthesis is good mixing - Nicodem
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benzylchloride1
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Here is the JACS paper that my synthesis of 3-Nitrophthalic acid was adapted from. I may attempt a 1/4 scale synthesis of the 3-nitrophthalic acid and
compare the yields. I am ordering 1kg of phthalic anhydride, so I will have plenty of the starting material. At least phthalic anhydride is dirt cheap
from most chemical suppliers. I attempted a luminol synthesis today, but I broke the reaction flask with a thermometer while I was boiling away the
water. All of a sudden, I saw smoke comming from my heating mantle, and removed the flask. Reaction mixture spilled all over the fume hood. The
heating mantle did not trip the circuit breaker because most of the liquid was flash evaporated due to the high temperature of of the heating mantle.
Glascol claims that mantles can melt flasks! I am obtaining my hydrazine from hydrazine sulfate by adding the theoreatical amount of sodium hydroxide
to a mixture of hydrazine sulfate in water.
Attachment: The Preparation of 3-Nitrophthalic Acid.pdf (138kB)
This file has been downloaded 1936 times
[Edited on 17-6-2009 by benzylchloride1]
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Formatik
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Some more references on 3-nitrophthalic acid:
Formation: by heating 4-hour heating of 1g 3-nitro-1,2-dimethylbenzene with 10 cc nitric acid (D= 1.15) in a closed tube to 170-180 deg. (Crossley,
Renouf, Soc. 95, 208). By the oxidation of 3-nitro-2-formylbenzoic acid in alkaline solution with KMnO4 (Wegscheider, Kusy v. Dubrav, M. 24, 821).
Next to 4-nitro-phthalic acid by heating phthalic acid with nitric-sulfuric acid (Faust, Lieb. Ann. 160, 57; Miller, Ber. 11, 393; Lieb. Ann. 208,
225), or by treatment of phthalic acid with highly conc. nitric acid at 30 deg. (Huisinga, R. 27, 277). Next to 4-nitrophthalic acid by nitration of
phthalic anhydride (Claus, May, Ber. 14, 1330 Anm.; Edinger, J. pr. [2] 53, 382; Bogert, Boroschek, Am. Soc. 23, 744; Seidel, Bittner, M. 23, 418). By
heating 4- or 7-nitrophthalide (Mp. 135 deg.) with nitric acid in a sealed tube (Hoenig, Ber. 18, 3452). Next to other products by prolonged boiling
of napthalene with HNO3 (Marignac, Lieb. Ann. 38, 7; Laurent, Lieb. Ann. 41, 107, 110).
By the oxidation of 1-nitronapthalene with potassium permanganate solution (Guareschi, Ber. 10, 294). Next to small amounts of 4- or 7-nitrophthalide
by the oxidation of 1-nitronapthalene with chromic acid in acetic acid (Beilstein, Kurbatow, Lieb. Ann. 202, 217). By heating 1,5-dinitronapthalene
with nitric acid (D = 1.15) in a closed tube to 150 deg., next to 3,5-dinitrobenzoic acid and other products (Bei., Kur., Lieb. Ann. 202, 220; also De
Aguiar, Ber. 5, 899). Next to 3,5-dinitrophthalic acid and picric acid by heating 1,8-dinitronapthalene with nitric acid (D: 1.15) in closed tube to
150 deg. (Bei., Kur., Lieb. Ann. 202, 225). There is also a laborous procedure for preparing it from 1-nitronapthalene in 90% acetic acid oxidation
via CrO3 (citign: Beils., Kurb.,; Bogert, Boroschek) and some properties (solubility, etc.) in Beilstein.
Attachment: 3-nitrophthalic.pdf (353kB)
This file has been downloaded 1137 times
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Sauron
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Why are you getting yields about 20% when the JACS paper claims much much better?
Vogel cribbed "his" procedure as usual from Org Syn but I believe Org Syn latter appended a safety warning, q.v.
Sic gorgeamus a los subjectatus nunc.
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benzylchloride1
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I am planning on conducting a larger scale preparation of 3-nitrophthalic acid by the method in the ACS paper, so that I can compare the yields and
see what could have gone wrong with this synthesis. 20% is an extremely low yield. The product is very soluble in water and much was probably lost in
the waste acid. The fifth edition of Vogel has the same Organic Syntheses safety warning. The nitration of phthalic anhydride by the method described
in the JACS paper did not procede with violence; nitrogen dioxide was only produced when the mixture was heated in a hot water bath. I used a Buchi
Rotovapor water bath; I live at high elevation, so water in the water bath boils at 94 C. The low temperature could have decreased the yields. I have
an I2R Thermowatch; I could use this to maintain the temperature at 100 C during the entire course of the reaction, a higher temperature of the
reaction mixture may increase the yield. Formatik, thank you for the other methods of preparation.
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Picric-A
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Can 3-nitrophthalhydrazide be reduced with anything other than Sodium dithionite?
Would NaOH/Al work?
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benzylchloride1
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Sodium dithionite can be isolated from Wink brand iron remover. Hydrolysis of the hydrazide could occur with the highly alkaline conditions of a
sodium hydroxide and aluminum mixture.
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Formatik
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In a paper describing chemiluminescence of title and related compounds, Chemiluminescenz cyclischer Hydrazide, R. Wegler. J. pr. Ch. 256
(1937), 146, compared to H2S which was used by E.H. Hundress, hydration was done with Pd-charcoal where it was said reduction is simple and in
complete yield. Some reductions were also done on other compounds with tin-hydrochloric acid (e.g. 3-nitrophthalicbenzyl hydrazide to the amine).
Wegler says 3-hydrazino-phthalic acid hydrazide also glows brighter than luminol, though it's short lasting.
Attachment: J. pr. Ch. 256, 135.pdf (1.9MB)
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Magpie
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Quote: Originally posted by benzylchloride1  | | I am planning on conducting a larger scale preparation of 3-nitrophthalic acid by the method in the ACS paper, so that I can compare the yields and
see what could have gone wrong with this synthesis. 20% is an extremely low yield. The product is very soluble in water and much was probably lost in
the waste acid. The fifth edition of Vogel has the same Organic Syntheses safety warning. The nitration of phthalic anhydride by the method described
in the JACS paper did not procede with violence; nitrogen dioxide was only produced when the mixture was heated in a hot water bath. I used a Buchi
Rotovapor water bath; I live at high elevation, so water in the water bath boils at 94 C. The low temperature could have decreased the yields. I have
an I2R Thermowatch; I could use this to maintain the temperature at 100 C during the entire course of the reaction, a higher temperature of the
reaction mixture may increase the yield. Formatik, thank you for the other methods of preparation. |
With my newly prepared phthalic anhydride I too am exploring the synthesis of 3-nitrophthalic acid. As did BZ1 I used the Littmann procedure at 10%
scale through the first wash. I used an oil bath to control the temperature to 100C for 3 hours. This was uneventful with only NOx being evolved as
evidenced by brown fumes. I did not use a reflux condenser but left a watch glass on the 250mL Erlenmeyer flask for 1 hour then took that off.
Continuing the workup, I did not do the Littmann prescribed azeotropic distillation to remove water and HNO3 using benzene. Instead, I Buchner funnel
suction dried, then air dried overnight the very pale yellow product. The yield at this point was 66% assuming a 3-:4- nitrophthalic acid isomeric
split of 48:52 per the reference provided below. Open tube melting point was 186-190C. Handbook value for the 3- isomer is 218C; for the 4- isomer
it is 165C.
I then washed the 8.4g of product with 16mL of water, then suction dried on a 7cm Buchner funnel with a few mL H2O as wash. The product was then
air-dried overnight. Yield now was down to 47%. Open tube mp was 198-206C; closed tube mp was 208-218C.
Although I would like to get a more pure product, I think it is good enough for the Luminol synthesis, and with the inevitable losses from another
wash this might well give a diminishing return.
Reference: "Purification of 3-Nitrophthalic Acid from the Nitration of Phthalic Anhydride," 1979, P. Furrer, H. Beyeler, Ciba-Geigy Corp, US Patent
4284797.
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