Dry diazonium nitrates from aromatic amines and tributyl phosphate-NO2 adduct

Article abstract of DOI:10.1002/jccs.200100018

Aromatic amines reacted with TBP-NO₂ adduct to give dry aryl diazonium nitrate in high purity and yield.

Full text of DOI:10.1002/jccs.200100018

JournaloftheChineseChemicalSociety, 2001, 48, 101-104
101
Dry Diazonium Ni trates from Ar o matic Amines and Tributyl
Phosphate-NO2 Adduct
Qingzhi Zhang (
), Xinming Liu (
),
Shensong Zhang* (
) and Jinming Zhang (
)
CollegeofChemistryandEnvironmentalScience,HenanNormalUniversity,
Xinxiang 453002, P. R.China
Ar o matic amines re acted with TBP-NO2 adduct to give dry aryl diazonium ni trate in high pu rity and
yield.
INTRODUCTION
(tributylphosphate)wasusedasanabsorbentofNO2. The re-
sultantabsorbentproduct,TBP-NO2, proved to be a se lec tive
andmoderateoxidant,whichcanconvertthearomaticmetha-
nolintocorrespondingaldehydesorketonesinhighyields.17
In this work, the re ac tion of TBP-NO2 with ar o matic amines
to give arenediazonium ni trates was stud ied.
Since the dis cov ery of diazonium com pounds in 1858,
more than a cen tury has wit nessed the syn the sis, the high re-
activityandapplicationoftheseinvaluablecompounds.Ap-
pli ca tions of diazonium salts have long been im por tant in
boththedyeandthepharmaceuticalindustries.1-7 Re cently,
diazonium salts have also found new ap pli ca tion in the re-
cording, imaging, copying and printing sciences.8-13 The
most fre quently em ployed diazonium salts in these fields are
clas si cal arenediazonium chlo rides, tetrafluoroborates, hy-
drosul fates and dihydrophosphates.1-4 How ever, stud ies of
thediazoniumnitrateshavebeenseldominvolvedbecauseof
thestrongoxidizationofnitricacid. Inordertoavoidtheoxi-
da tion of ar o matic amines by ni tric acid, N2O4 in CHCl3 was
treated with phenyl isocyanates by Backman to ob tain diazo-
nium ni trates.14 Re cently, Kagiyama and Tsurushima15 re-
ported a suc cess ful method us ing alkyl ni trites to pre pare
diazonium ni trates, while Wagenblast16 re acted NO2 in the
gaseousorliquidphasewitharomaticaminestoobtaincorre-
spondingdiazoniumnitrates.
RESULTS AND DISCUSSION
When TBP-NO2 adduct was mixed with aromatic
amines in TBP, the diazonium precipitatedimmediately;
work-up by recrystallization gave a dry and pure prod uct.
The IR peaks at 2252-2293 cm-1 con firm the pres ence of
+
ArN2 , while the peaks at 1384 cm-1 and 825-826 cm-1 are as-
signedtothevibrationofnitrateanions.Elementalanalyses
and 1H NMR data also con firm the struc tures.
The arenediazonium ni trates with elec tron- withdraw-
ing sub stitu ents (com pounds2j-2o) were pre pared at 10-40
C in ex cel lent yield. These salts prove to be very sta ble and
can be stored at room tem per a ture in a des ic ca tor for a half a
year with out any change. The diazonium ni trates with out
electron-withdrawingsubstituents(compounds 2a-2i) were
ob tained at lower re ac tion tem per a tures (10-15 C) in good
yield. Higher re ac tion tem per a ture leads to the for ma tion of
tar. These salts can be stored at 10-15 C for two months; stor-
age at room tem per a ture makes these salts grad u ally darken.
When heated to about 65 C or struck or ig nited, all the dry
diazonium salts ex plode.
In the course of our study on the treat ment and uti li za-
tion of the waste gas NOX with or ganic com pounds, TBP
a
e
b
---
R
TBP NO2
R
-
+ NO3
c
NH2
N2
d
_
_
1a 1o
2a 2o
a) H
d) o-Cl
g) o-Br
j) o-CO2H
m) o-NO2
b) o-CH3
e) m-Cl
h) m-Br
k) m-CO2H
n) m-NO2
c) m-CH3
f) p-Cl
i) p-Br
l) p-CO2H
o) p-NO2
As syn thetic in ter me di ates, these dry and pure diazo-
nium ni trates are ex pected to be more use ful than other diazo-
nium salts. Ap pli ca tion of these diazonium salts is un der in-
vestigation.

102 J. Chin. Chem. Soc., Vol. 48, No. 1, 2001
Zhang et al.
EXPERIMENTALSECTION
(w, sharp), 1384 (vs), 826 (w);1H NMR (D-DMSO): 8.65 (d,
Jab = 8.0 Hz, 1H, H a), 8.15 (t,Jcb = Jcd = 7.6 Hz, 1H, Hc), 7.84
(d, Jdc = 7.6 Hz, 1H, Hd), 7.79 (t, Jba = Jbc = 8.0 Hz, 1H, Hb),
2.74 (s, 3H, CH3). Anal. Calcd. for C7H7N3O3: C, 46.40; H,
3.90; N, 23.20; Found: C, 46.61; H, 4.04; N, 23.75.
Starting ma te ri als are re agent grade and used with out
furtherpurification.AFTS-40infraredspectrophotometer
was uti lized to re cord spec tra of sam ples.1H NMR spec tra
were ob tained on a Bruker DPX-400 spectrometer using
TMS as an in ter nal stan dard. El e men tal anal y ses were per-
formed by PE-2400 microelemental analyser.
m-Toluenediazonium nitrate (2c)
Col or less nee dles; Yield: 86%; IR (KBr, cm-1): 2279
(m, sharp), 1384 (vs), 825 (w); 1H NMR (D-DMSO): 8.51 (d,
Jab = 7.2 Hz, 1H, Ha), 8.50 (s, 1H, He), 8.09 (d, Jcb = 8.2 Hz,
1H, H c), 7.87 (t, Jba =Jbc = 7.4 Hz, 1H, Hb), 2.50 (s, 3H, CH3).
Anal. Calcd. for C7H7N3O3: C, 46.40; H, 3.90; N, 23.20;
Found: C, 46.74; H, 3.73; N, 23.48.
General Procedure for the PreparationofTBP-NO
2
Adduct
Inatypicalprocedure, to21.1g(0.3mol)ofsodiumni-
trite (98%) in a three-neck round bot tom flask was added
dropwise 18 g (0.18 mol) of conc. sul fu ric acid (98%)via a
pres sure-equalized drop ping fun nel. The evolved NOX gases
were blown by ox y gen through a con denser into a dry ing
tower (packed with ca. 80 g of the mix ture of phosphrous
pentaoxide and quartz sand, P2O5 : SiO2 = 1 : 1 in wt.), then
through an ox i diz ing tower (packed with ca. 100 g of quartz
sandcarryingchromiumtrioxide,CrO3 : SiO2 = 5 : 95 in wt.)
andfinallyintothebottomofanabsorptiontower(height300
mm, in side di am e ter 15 mm, packed with glass ring). From
the top of the ab sorp tion tower, 79.9 g (0.3 mol) of TBP was
addeddropwisetoinducecounterfaceabsorption. Controlof
the rate of ad di tion of TBP and of sul fu ric acid and the flow of
oxygenmadeacompleteabsorptionofNO2.Theabsorption
solutioncollectedinthebottomoftheabsorptiontoweristhe
TBP-NO2 adduct.
o-Chloro ben zene diazonium ni trate (2d)
Col or less nee dles; Yield: 80%; IR (KBr, cm-1): 2273
(m, sharp), 1384 (vs), 826 (w); 1H NMR (D2O): 8.60 (d,Jab =
8.6 Hz, 1H, Ha), 8.20 (t, Jcb = Jcd = 8.0 Hz, 1H, H c), 8.00 (d,Jdc
= 8.2 Hz, 1H, Hd), 7.83 (t, Jba = Jbc = 8.4 Hz, 1H, Hb). Anal.
Calcd. for C6H4ClN3O3: C, 35.75; H, 2.00; N, 20.85; Found:
C, 34.96; H, 1.82; N, 20.46.
m-Chlorobenzene diazonium nitrate (2e)
Col or less nee dles; Yield: 82%; IR (KBr, cm-1): 2305
(w), 1384 (vs), 826 (w); 1H NMR (D2O): 8.60 (s, 1H, He),
8.49 (d, Jab = 8.0 Hz, 1H, Ha), 8.25 (d, Jcb = 8.4 Hz, 1H, Hc),
7.88 (t, Jba = Jbc = 8.4 Hz, 1H, H ). Anal. Calcd. for
b
C6H4ClN3O3: C, 35.75; H, 2.00; N, 20.85; Found: C, 35.81;
H, 1.89; N, 20.93.
Arenediazonium Nitrates. General Procedure
To 5.0 mmol of ar o matic amine dis solved in 10 mL of
TBP at 10-15 C, was added 11 mL (40 mmol) of TBP-NO2
im me di ately with vig or ous stir ring. The diazonium salt pre-
cip i tated im me di ately. The crude prod uct was fil tered and
washed with Et2O. Recrystallisation by dis solv ing the crude
prod uct in DMF and then add ing Et2O and evap o ra tion in
vacuo gave pure and dry diazonium salts.
p-Chloro ben zene diazonium ni trate (2f)
Col or less nee dles; Yield: 83%; IR (KBr, cm-1): 2276
(w), 1384 (vs), 826 (w); 1H NMR (D2O): 8.52 (d, Jab = 8.8 Hz,
2H, H ), 7.93 (d, Jba = 8.8 Hz, 2H, Hb). Anal. Calcd. for
a
C6H4ClN3O3: C, 35.75; H, 2.10; N, 20.85; Found: C, 35.78;
H, 1.96; N, 21.02.
o-Bromobenzene diazonium nitrate (2g)
Benzenediazonium ni trate (2a)
Col or less nee dles; Yield: 84%; IR (KBr, cm-1): 2267
(m, sharp), 1384 (vs), 826 (m); 1H NMR (D2O): 8.61 (d,Jab =
8.0 Hz, 1H, Ha), 8.16 (d,Jdc = 8.4 Hz, 1H, Hd), 8.10 (t,Jcd =Jcb
= 7.8 Hz, 1H, Hc), 7.88 (t, Jba = Jbc = 7.8 Hz, 1H, Hb). Anal.
Calcd. for C6H4BrN3O3: C, 29.29; H, 1.64; N, 17.08; Found:
C, 28.91; H, 1.79; N, 17.30.
Col or less nee dles; Yield: 90%; IR (KBr, cm-1): 2294
(m, sharp), 1384 (vs), 825 (w);1H NMR (D-DMSO): 8.68 (d,
Jab = 8.8 Hz, 2H, Ha), 8.26 (t, Jcb = 7.6 Hz, 1H, H c), 7.98 (t,Jba
= Jbc = 8.2 Hz, 2H, H b). Anal. Calcd. for C6H5N3O3: C, 43.11;
H, 3.02; N, 25.1; Found: C, 43.22; H, 3.15; N, 25.16.
o-Toluenediazonium ni trate (2b)
m-Bromobenzene diazonium nitrate (2h)
Col or less nee dles; Yield: 84%; IR (KBr, cm-1): 2261
Col or less nee dles; Yield: 85%; IR (KBr, cm-1): 2276

Dry Diazonium Ni trates
J. Chin. Chem. Soc., Vol. 48, No. 1, 2001 103
(m, sharp), 1384 (vs), 826 (w); 1H NMR (D-DMSO): 8.90 (s,
1H, He), 8.69 (d, Jab = 8.4 Hz, 1H, Ha), 8.38 (d, Jcb = 8.2 Hz,
1H, Hc), 8.02 (t, Jba = Jb c = 8.4 Hz, 1H, Hb). Anal. Calcd.
C6H4BrN3O3: C, 29.29; H, 1.64; N, 17.08; Found: C, 29.41;
H, 1.48; N, 17.18.
He), 9.05 (d, Jab = 8.4 Hz, 1H, Ha), 8.99 (d, Jcb = 8.6 Hz, 1H,
Hc), 8.25 (t, Jba = Jb c = 8.4 Hz, 1H, Hb). Anal. Calcd. for
C6H4N4O5: C, 33.97; H, 1.90; N, 26.42; Found: C, 34.10; H,
1.42; N, 26.46.
p-Nitrobenzene diazonium nitrate (2o)
p-Bromobenzene diazonium ni trate (2i)
Light yel low nee dles; Yield: 90%; IR (KBr, cm-1): 2298
(w), 1386 (s), 826 (w);1H NMR (D-DMSO): 8.94 (d,Jab = 7.2
Hz, 2H, Ha), 8.72 (d, Jba = 7.2 Hz, 2H, Hb). Anal. Calcd. for
C6H4N4O5: C, 33.97; H, 1.90; N, 26.42; Found: C, 33.82; H,
1.69; N, 26.51.
Col or less nee dles; Yield: 86%; IR (KBr, cm-1): 2274
(s), 1384 (vs), 826 (m);1H NMR (D2O): 8.42 (d, Jab = 9.2 Hz,
2H, H ), 8.12 (d, Jba = 9.2 Hz, 2H, H ). Anal. Calcd.
a
b
C6H4BrN3O3: C, 29.29; H, 1.64; N, 17.08; Found: C, 29.51;
H, 1.76; N, 17.25.
o-Carboxybenzene diazonium ni trate (2j)
Received June 19, 2000.
Col or less nee dles; Yield: 94%; IR (KBr, cm-1): 2280
(m), 1384 (vs), 826 (w);1H NMR (D2O): 8.58 (d,Jab = 8.0 Hz,
1H, Ha), 8.29 (d, Jdc = 7.6 Hz, 1H, Hd), 8.20 (t, Jcb = Jcd = 7.6
Hz, 1H, Hc), 7.97 (t, Jba = Jb c = 7.8 Hz, 1H, Hb). Anal. Calcd.
for C7H5N3O5: C, 39.82; H, 2.39; N, 19.90; Found: C, 39.91;
H, 2.32; N, 19.78.
Key Words
Diazonium nitrates; Aromatic amines; TBP-NO2.
REFERENCES
m-Carboxybenzene diazonium nitrate (2k)
1. Zollinger, H. Diazo and Azo Chemistry; Wiley: New
York, 1961.
Col or less nee dles; Yield: 95%; IR (KBr, cm-1): 2284
(m), 1385 (m), 826 (w); 1H NMR (D-DMSO): 9.02 (s, 1H,
He), 8.69 (d, Jab = 8.0 Hz, 1H, Ha), 8.65 (d, Jcb = 8.4 Hz, 1H,
Hc), 7.98 (t, Jba = Jbc = 8.2 Hz, 1H, Hb). Anal. Calcd. for
C7H5N3O5: C, 39.82; H, 2.39; N, 19.90; Found: C, 39.90; H,
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p-Carboxybenzene diazonium ni trate (2l)
Col or less nee dles; Yield: 91%; IR (KBr, cm-1): 2290
(s), 1384 (vs), 825 (w); 1H NMR (D2O): 8.61 (d, Jab = 8.8 Hz,
2H, H ), 8.35 (d, Jba = 8.8 Hz, 1H, Hb). Anal. Calcd. for
a
C7H5N3O5: C, 39.82; H, 2.39; N, 19.90; Found: C, 39.95; H,
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o-Nitrobenzene diazonium nitrate (2m)
Lightyellowneedles;Yield:88%;IR(KBr, cm-1 ): 2275
(m), 1384 (s), 826 (w); 1H NMR (D2O): 8.98 (d,Jab = 8.4 Hz,
1H, Ha), 8.80 (d, Jdc = 8.4 Hz, 1H, Hd), 8.53 (t, Jcb = Jcd = 8.0
Hz, 1H, Hc), 8.35 (t, Jba = Jb c = 8.0 Hz, 1H, Hb). Anal. Calcd.
for C6H4N4O5: C, 33.97; H, 1.90; N, 26.42; Found: C, 33.97;
H, 1.79; N, 26.65.
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m-Nitrobenzene diazonium nitrate (2n)
13. Ohkawa, A.; Yamada, H. Eur. Pat. Appl. EP 930,529
1999.
Lightyellowneedles;Yield:92%;IR(KBr, cm-1 ): 2292
1
(m), 1384 (vs), 825 (w); H NMR (D-DMSO): 9.63 (s, 1H,
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