Chemistry of High Energy Materials - The Scripps Research Institute

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
High Energy Materials
History of Explosives
7th century A.D.- "Greek Fire" petroleum distillate used by
Byzantines of Constantinopole
Explosives
High Explosives
[detonate]
Non-explosive materials
Low Explosives
[deflagrate-burn rapidly]
13th century - black powder (aka gunpowder) Chinese alchemists
18th century - black powder composition became standardized:
KNO 3 /charcoal/sulfur (75/15/10 w/w)
19th century - NH 4 NO 3 replacement for KNO 3 in black powder
1846 - Italian Chemist Ascanio Sobrero invented nitroglycerin (NG)
1863 - German chemist Julius Wilbrand invented 2,4,6-trinitrotoluene (TNT)
originally used as a yellow dye. Potential as an explosive not appreciated
due to difficulty to detonate (insensative).
1° Explosives 2° Explosives Propellants Pyrotechnics
[detonate by ignition]
- Lead azide
- Tetrazene
[need detonator]
- TNT
- RDX
- Black powder
- liquid/solid
Organic Chemistry of Explosives by J.P. Agrawal and R.D. Hodgson
- Fireworks
- Color/flash/sound
Prof. Thomas Klapotke - Ludwig-Maximilians-Universität München - Germany
Chair of inorganic chemistry
Dr. Michael A. Hiskey - Los Alamos National Laboratory
What makes an explosion?
Exothermic chemical reaction comprised of an oxidant and fuel, which releases
energy (gas and heat) in a given time interval.
Whats the difference between explosive, propellants and pyrotechnics?
Rate at which it burns (Flamming gummy bear vs. rocket booster vs. TNT)
Speed of reaction will determine subsonic vs. supersonic blast pressure waves
1866 - Mixing of NG with silica (PBX) to make malleable paste (dynamite)
late 19th century - nitration chemistry on common materials (resins,cotton, etc.)
1910 - military use of TNT for artillery shells and armour-piercing shells
1939-1945 - World War II - Research on explosives intesified (nitration chemistry)
Developlment of cyclotrimethylenetrinitramine (RDX) and
cyclotetramethylenetetranitramine (HMX).
Introduction to high energy materials terminology
Brisance: Shattering capabiliy of explosive. Measure of rate an explosive
develops its maximum pressure.
Relative effectiveness factor (R.E. factor): Measurement of an explosive's
power for military purposese. It is used to compare an explosive's
effectiveness relative to TNT by weight (TNT equivalent/kg or TNTe/kg).
Detonation velocity (VoD): The velocity at which the shock wave front travels
through a detonated explosive. Difficult to measure in practice so use
gas theory to make prediction.
Specific impulse (I sp ): The force with respect to the amount of propellant used
per unit time. Used to calculate propulsion performance.
Oxygen balance (OB%): Expression used to indicate degree to which explosive
can be oxidized. If explosive contains just enough oxygen to form carbon
dioxide from carbon, water from hydrogen molecules and all metal oxides from
metals with no excess, the explosive is said to have zero oxygen balance.

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
Chemical types/class of organic explosives
Aromatic C-nitro compounds
Aliphatic C-nitro compounds
NO
NO 2 NO 2
2
R 2
NO 2
Me
HO
(NO
acidic protons
2 )x
R NO 2 R 1 NO 2
R NO 2 (condensation
1° nitroalkane 2° nitroalkane Terminal
chemistry) O 2 N NO
O 2 N NO 2 O 2 N NO 2
x ≥ 4
2
poor chemical
gem-dinitroalkane
TNT 1,3,5-trinitrobenzene 2,4,6-trinitrophenol
stability
(TNB)
(picric acid)
R 2 NO 2
R 3
R 2
R 2
NO 2
high explosive with Aliphatic O-nitro compounds Aliphatic N-nitro compounds
R 1 R 1 NO 2
R 1 NO high thermal and
2
NO 2
NO 2 Internal chemical stability
O 2 N
NO
3° nitroalkane Trinitromethyl O 2 NO
ONO 2
NO 2
2
gem-dinitroalkane
N N
ONO 2
N
NO 2 Nitroglycerin (VOD=7750 m/s)
heterocycles
O 2 NN NNO 2
N N
N N
NO 2
ONO 2
O 2 N NO 2 O 2 N
NO
O 2
2 NO
RDX (VOD=8440 m/s) HMX (VOD=9110 m/s)
O 2 N NO O 2 2 NN NNO O
2
ONO 2
NO 2
N
O 2 NO
O 2 N
NO 2
N
H
S O
N N
Pentaerythritol tetranitrate
H H
H
(PETN) (VOD=8310 m/s)
2 N NH
Nitro derivatives of pyrroles, thiopenes, and furans are not practical explosives:
N,N'-dinitrourea
2
1. heat of formation offers no benefits over standard arylene hydrocarbons
(DNU)
nitroguanadine
2. during nitration, these heterocycles are much more prone to oxidation and
NO
O 2 NO 2
ONO 2
acid cat. ring opening compared to arenes
O 2 N NO 2
O 2 N
NO
O ONO N N 2
H-bonding
O 2 NO
H NO 2
2 N NO 2 N
O
2
2
O 2 NN
O NO
NNO 2 N
reduction in
2
N N 2
N NH
N
novel energetic nitrate eseter
sensativity
N
O ONO
N N
2 N
N
O
2
F 2 N NF 2
O 2 N
H
O NO 2 NO
2
NO 2
N
4-amino-3,5-dinitropyrazole 2,4-dinitroimidazole furazans/benzofurazans
Si
3,3-bis(difluoroamino)
Hexanitrohexaazaisowurtzitane
(LLM-116)
(2,4-DNI) furoxans/benzofuroxans
ONO
octahydro-1,5,7,7-
2
O 2 NO
tetranitro-1,5-diazocine
(HNIW or CL-20)
NH O
2 NH 2
(TNFX)
O 2 N
N
Si-PETN
(VOD=9380 m/s)
O 2 N
NO 2 O 2 N N NO 2
O
N N
N
H H 2 N
H
2 N
N N
N
N
N
N
O 2 N
O
N N
H 2 N N NH 2 H 2 N N NH 2 O
NO
Ar
N
Ar
Ar
2
N N
N
NO
O
N NH
NH N
2
O
2
O
benzotriazoles H
H
1,3,4-oxadiazoles 3-nitro-1,2,4-triazol-5-one
pyridine N-oxide pyrazine N-oxide tetrazine N-oxide
tetrazoles 1,2,4 triazoles
(NTO)

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
Nitration chemistry
The nitro gorup whether attached to aromatic or aliphatic carbon, is probably
the most widely studied of the functional groups and this is in part attributed
to its use as an 'explosophore' in many energetic materials.
Borgardt et al. Chem Rev 1964. 64, 19 (polynitro functionality)
Routes to C-Nitro functionality
Direct nitration of aliphatic and alicyclic hydrocarbons possible in the vapor
phase using HNO 3 or NO 2 (toxic redish-brown gas) at elevated temperatures.
[2+2]
TMS AcONO2 NO 2
TMS
O
N
O
_
OAc
NO 2
+
NO 2
O
N
O
_
OAc
NO 2
NO 2
ONO 2
AcONO 2
Nef
NO 2
O
N
O OAc
O
ONO 2
H
Me
Me
Me
NO 2
Me
Me
Me
O
O
Radical methods
Ph
HNO 3
25%
N 2 O 4
N
N
O
O
- colorless liquid
1 atm NO
DCE/ rt
O 2 N
H
Me
O 2 N
Me
Me
dinitro
Ph
NO 2
NO 2
Me
NO 2
Me
Me
Mukaiyama et al. Chem Lett 1995. 505
H
R
H
R
H
R
NO 2
H
R
NaNO 3 xs,
CAN 2eq
AcOH/CHCl 3
80 - 90%
H
R
H
R
+
Nitration with HNO 3 is difficult
O 2 N
Me
Me
ONO
Me
Me
nitro-nitrite
NO 2
+
Ph
+
O 2 N
Me
Me
ONO 2
Me
Me
nitro-nitrate
OH
76% 23%
Al 2 O 3
NO 2
R
NO 2
H
R
Hwu et al. J Chem Soc Chem Commun 1994. 1425
Taniguchi et al. JOC 2010. 75, 8126
Ph
R
R
Ph
92%
NO 2
Fe(NO 3 ) 3 9H 2 O
FeCl 3
MeCN, reflx
NO 2 BF 4
MeCN
Ph
R
NO 2
Cl
R NO 2
80 - 90%
NHAc
84%
NO 2
alkaline nitration
O 2 N
O 2 N
Br
NO 2
NO 2
O 2 N
2. N 2 O 4
1. NaHMDS
NO 2 74%
1. nBuLi
N
N
CO 2 R
O 2 N
NO 2
2. N 2 O 4 -78 °C
S
S
77%
O 2 N
NItration selectivity on arene/heteroarene
Kakiuchi, et al. Synlett 1999. 901
F 3 C
O
O
O
CF 3
TBAN
F 3 C
O
O
Cl
NO 2
NO 2
O 2 N
NO O 2 N
2
KNO 3
H 2 SO 4
traditional
[NO + 2 ]
44%
TBAN
TFAA
76%
N
N
NO 2
O 2 N NO 2
NO
O 2 N
2 NO 2
N
CO 2 R
N
CO 2 R
Cl
Cl
NO 2
* No rxn in
presence of
TEMPO

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
1° and 2° nitro compounds
Victor Meyer rxn
- alkyl chlorides too slow
- only good for 1° (2° alkyl halide gives nitrate ester)
- nitrate ester arises from desproportionation of silver nitrate acc. by heat/light
R
modified VM (alkali metal nitrites e.g. NaNO 2 ) time and solubility is VIMP
F NO 2
R
R
R N O
R NO R
NaNO 2
X
NO 2 + O
NO 2
fast
slow
R
R
R nitrite ester
R
R
OH
OH
O
H + O N
R
OR
NO 2
HO OH
R
phloroglucinol
O O
Fluorotrinitromethane
NO 2
NO 2 (or)
NO 2
NO 2
NO 2
O 2 N NO 2 F NO 2
NO 2
gem-dinitros from acids
R
R
HNO NO 3
2
NO
HNO 2
CO 2 H
3
R
20 - 30%
MeO 2 C CO 2 H
R NO 2
60 % MeO 2 C NO 2
oxidation of amines
NH + 3 Cl -
NO 2
DMDO
C+H 3 N
Acetone
O 2 N
NH 3 +C 91%
NO 2
C+H 3 N
O 2 N
oxidation of isocyanates
NCO
NO 2 via amine thus
DMDO
H 2 O essential
Eaton et al. JOC 1988. 5353
OCN
X
+
NaNO 2
DMSO
N
O
OAg
ether
Acetone/H 2 O
85%
+ AgX
R NO 2 R O NO
O 2 N
Kornblum et al. JACS 1956. 78, 1497
O
O
NO 2 H
NOH
1.KOtBu
1. NBS
amyl nitrate
2. H + 2. [O]
3. [H]
NO 2
CF 3 CO 3 H
O
N
OH
S 2 O 8 2-
NO 2
only useful
oxidant
O 2 N NO 2
H +
NO
+ 2 O 2 N NO 2
Kaplan
Shechter Rxn
NO
Synthesis of an energetic nitrate ester O 2 NO 2
ONO 2
Chavez, D.E. et al. Angew. 2008, 47, 8307 O 2 NO
ONO
NO 2
2
R 1 R 2
Me
Me
O
Me
NO 2
N
R 1 R 2
N
O
Me
O
O
O
O
O
O Na
O
O O
NaOH N 1. NaNO 2
NO 2
N
O
NH
N
NH
N
Original Target/Route via modified Kaplan Shechter Rxn
N
NH
N
Me
Me
O
O
O
N
N
O
O
O
O 2 N
NO 2
Ag 0
2. AgNO
R 1 R 3 R1 2
R 2
Ag +
nitronate
Ag + Ag
O O
O O
-Ag 0 O O
O N N O
O N N
O N N O
O
R 1 R 2
R
R 1 R 1 R 2
2
N
activation
NH
N
O 2 N
NO 2
+
NO 2
(low yields)
Me
Me
O
O
O
N
Fe
O
NH
N
N
retro
aldol
-CH 2 O
N
NH
[O]
Me
Me
R
R
O
O
O
N
O
NH
N
NO 2
OH
N
NH
N

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
Initial Results: homocoupled product
1.cat. K 3 [Fe(CN) 6 ]
Na 2 S 2 O 8
Routes to O-Nitro functionality
1. 2 - methoxypropene
HO NO 2 cat. H +
Me O O
- Use of mixed acids (esterification) and nitrogen oxides described for C-Nitraion
Me
N
2. NaOH
H
Key points:
HO OH
O O
N
N
1. fuming (anhydrous) HNO
X
3 prep: dry air bubbled through anhydrous HNO 3 to
H 2 N
remove any oxides of nitrogen present, followed by addition of trace urea
NO
Me O
N
N 2
N
O
to remove any nitrous acid present. AKA "white nitric acid"
N N
2. Urea destruction of nitrous acid important to avoid violent fume-off
O O O O Me
Me
NO
Me O 2 NH 3. O-nitrations with mixed acids of "white nitric acid" above ambient temperatures
N N
O
O Me
NO 2
Me
NH is dangerous and has increase risk of explosion
12%
4. anhydrous HNO
O
3 /Ac 2 O- Acetyl nitrate is generally a weak nitrating agent but
in the presence of a strong acid like HNO 3 , ionization to nitronium ion occurs
O O O O
NO 2
NO 2
NO 2
Me Me
Me Me
O O
O
O O
2 NO
ONO 2
anh HNO 3 HO
OH 90% HNO
N
3 HO
ONO 2
N
Me O
O
Ac 2 O
Ac
Me O
O
2 O
activation
Me
Me
Me
Me
O 2 NO
ONO 2 90% HO
OH 70% O 2 NO
OH
O
O Me
- CN - O
O Me
N
N
NO 2 NO
O O
2
NO 2
O O
shock sensative
NC CN
NaO 3 S
NC CN
Fe
NC Fe CN +CN -
Transfer nitration (neutral conditions - good for acid sensative alcohols)
O O
NC Fe OSO 3 Na
Me
-NaSO
-
NC CN
SO 3 Na
4
NC CN
BF
- 4
Me
NO
O
NO
Me O 2
2 NO 2
ONO
Me N Me
Olah G.A. et al JOC, 1965. 30, 3373
m.p. 86 °C
2 1.HCl, MeOH
O
OH
ONO
NO 2
Me
Me
2 eq 2
Det.Temp
+
BF
- 4
O 2 NO
ONO 2
2. Ac 2 O/HNO
works for 1°, 2°, 3° alcohols
140 °C
NO 3 O
O Me
MeCN
Me N Me
2
NO 2
OH quant yield ONO 2
72% (2 steps)
H
65% optimized
in situ halide displacement with AgNO 3
ONO 2
Low yields for 2°
O 2 NO
PPh 3 , I 2 AgNO 3 HgNO 3 can be used for 2° and
R OH
R I
R ONO 2 3° alkyl halide displacements
ONO 2
O 2 NO
decomposition of nitrocarbonates (very mild, rt or reflux MeCN)
20,164 MPH!!
comparable
stability to PETN
O 2 N
N
NO 2
N
RO
O
Cl
AgNO 3
Py
RO
O
ONO 2
-AgCl
-CO 2
ring opening of strained oxygen heterocycles
R ONO 2
80%
H 2 O
N N
N 2 O 4
O 2 N NO 2
ONO
O (or)
CH 2 Cl
ONO 2
CHEETAH calculates
2
[O]
as powerful as HMX
O
N 2 O 5
HO
O 2 NO
ONO 2
ONO 2

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
selective O-nitrations
HO
OH
nitrodesilylation
OH
1 eq SOCl(NO 3 )
2 eq SOCl(NO 3 )
70%
N 2 O 5
RO SiR 3
CH 2 Cl 2
RO ONO 2 + O 2 NO SiR 3
Routes to N-Nitro functionality
65%
O 2 NO
3 eq SOCl(NO 3 ) O 2 NO
100%
ONO 2
ONO 2
deamination
NO 2 F
R NH 2
MeCN
R ONO 2
- Compounds resulting from nitration of nitrogen are of far less use for
mainstream organic synthesis. However the N-NO 2 group is an important
'explosophore' and is present in many enrgetic materials
HN
N
O
O
OH
H +
N R OH + N 2 O
HO
OH
OH
ONO 2
ONO 2
- Direct nitration of a 1° amine to a nitramine using HNO 3 /mixed acids is not
possible due to instability of the tautomeric isonitramine in strongly acidic
conditions. 2° amines are more stable and can undergo electrophilic nitration
using HNO 3 /Ac 2 O
2° w/ HNO 3 /Ac 2 O
R
NC
NO 2
N
NO 2
N
CN
NO 2
Me N Me
93% 22% 6%
analines - must contain one or more nitro groups on the aromatic ring
How to get around this problem??
- synthesis via condensation chemistry (Mannich, 1,4 addition, etc)
What about if need more direct method??
-non-acidic nitrating reagents (nucleophilic nitration)
R NH 2
R
nBuLi
N
O
-78 °C R NHLi Et ONO 2
R N N
OLi
1. Na
-
O
Ar NH
Ar NH 2 2 Na +
Ar N N
2. EtONO 2
EtONO 2
O
H +
ONa
R NH
NO 2
H + NO 2
Ar NH
-chloride ion catalysis
anhydrous ZnCl 2 , hydrochloride salt of amine, or dissolved HCl(g) can serve
as a source of electropositive chloride under the oxidizing conditions of nitration
NC
2 HCl + 2HNO 3 + 3Ac 2 O 2AcOCl + N 2 O 3 + 4AcOH
AcOCl + R 2 NH R 2 NCl + AcOH
R 2 NCl + HNO 3 + Ac 2 O R 2 NNO 2 + AcOCl + AcOH
NO 2
N
CN
93%
HNO 3 /Ac 2 O
(w/o chloride)
R NH 2
2 HOCl
NC
- Nitrolysis of fully substituted nitrogen
R
N
CN
Wright et al. Can. J. Res. 1948. 26B, 294
HNO 3 /Ac 2 O
R = Cl - (N + )
HNO 3 /Ac 2 O
R = H
Ease of alkyl nitrolysis depends on stability of the resulting cation:
benzyl, tertiary (t-Bu), etc...
X
NC
NO
HNO
R NCl 3 /Ac 2 O 2 NaHSO 3 (aq)
2 R N
rupture of C−N bond leading to formation on N−NO 2
R 1
A
O
N
R 2
Path A
O 2 N
N R 2
R 2
+
Cl
R 1
CO 2 H
R 2 Path B
NO 2
B
R 1 N + R 2 OH
R 2
Nitramine formation via nitrolysis possible from:
R 1
R 1
NO
+ 2
N
Ph
R 1
R 1
NO 2
N
Ph
O
R 2 N NR 2
R 2 N SiR 3
R 1 N
R 2 N NO
O
R 2
NO 2
N
70%
R NHNO 2
R 2
CN
- carbamate
- urea
- formamide
- acetamide
- sulfonamide

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
Synthesis of Hexanitrohexaazaisowurtzitane (HNIW)
- Many nitramines are more powerful than aromatic C-nitro compounds and have
high brisance and high chemical stability and low sensativity to impact and
friction compared to nitrate ester explosives. This is why they are of interest to
military applications.
Bn
Bn
Bn Bn
O
Bn
NH 2
MeCN/H
H
2 O N N N
N N
Bn
Bn
N N
+ H
Ph
cat. H +
N
O
N N
N N
2 eq.
Bn
Bn
Bn Bn
Bn
H
Ph O
2 ,
NO
+
[O] Ph
Me [Pd] X 2
O Ac 2 O
X
N
N
N
decomp. messy. Nitration
of aromatic rings
Ph O
CrO3 Ph
N
N
Ac
O NO 2 N
2
1. N
N 2 O 4
N N
Ac 2. HNO O 2 N
N
3 /H 2 SO 4
N N
NO 2
via nitroso
N 93%
N N
Bn
O 2 N NO
DANGER!
2
99% HNO 3
Bn
Bn
Ac
N N
N
Bn
Bn
N N H 2 , Pd(OAc) Ac 2 N
Ac
N N 2 O, PhBr cat.
N
Bn
Bn 65% Bn
H 2 ,
O NO 2 N
2
[Pd]
N N
O 2 N
Ac
Ac
N N NO 2
Ac
N N 1. HCO
Ac
2 H
Ac
Ac
N N
N N
O 2 N NO 2. Ph, Δ
2
HN NH -H 2 O OHCN
HNIW aka CL-20
- explosive/propellant (low smoke-emission)
- most powerful to date (better oxidizer-to-fuel than RDX/HMX)
- first prep by Nielsen 1987 Naval Air Warefare
- pilot plant in 1990 for 200 kg in China Lake facility
- unmatched performance in specific impulse,
burn rate, detonation velocity (9.38 km/s = 21,000 MPH!!)
- highest density than any other explosive (d = 2.044 g/cm 3 )
- thermally stable (250 -260 °C) but sensative to mechanical stress
still greater stability than nitrocellulose, PETN and others.
- 4 different polymprphs with different densities/properties
N
N
Ac
N
Ac
N
NCHO
Syntheses of some nitramine explosives
NNs
HO
O 2 N
90%
NH 2 NH 2 NsCl, NNs NNs
K 2 CO 3 (aq)
O
OH
NH 2
NO 2
NNs
F 2 NSO 3 H,
HNF 2 , H 2 SO 4 ,
CFCl 3
OH
O 2 N
OH
NO 2
N
NO 2
TNAZ
Ns
95%
1. HNO 3 /NH 4 NO 3
urea, 33%
2. H 2 SO 4
92%
O 2 N
HBr-AcOH
160 °C
72%
NO 2
NNs
N N Ns
F 2 N NF 2
Br
OH
O
1. NaHCO 3 , NaI
DMSO, 100 °C
NH 3 + Br -
Br
NOH
Br
2. NaNO 2 , NaOH
K 3 Fe(CN) 6 , K 2 S 2 O 8
29% (2 steps)
O
O 2 N
1. CrO 3 , AcOH
2. HOCH 2 CH 2 OH
TsOH
NNs
HNO 3 /SbF 6
CF 3 SO 3 H
82% (2 steps)
1. O 3 , CH 2 Cl 2
2. DMS
3. NH 2 OH/NaOAc
86% (3 steps)
O 2 N
O 2 N
O
NNs
NO 2
O
N N NO 2
F 2 N NF 2
O
O
NNs
TNFX
(3,3 bis(difluoroamino)octahydro
1,5,7,7 tetranitro 1,5 diazocine)
NaOH, 80 °C
60 mmHg
CH 2 Br
N
NO 2
N
Br
HNO 3 /TFAA
81%
NNs
1. NaNO 2 (aq)
2. HCl (aq)
10%
O 2 N
N
NO
NNs
Br Br 76%
K 2 CO 3
CH 2 Br

R.A. Rodriguez
Chemistry of High Energy Materials
Baran GM
2012-08-18
N 2 O 5
No single nitrating agent is as diverse and versatile
It is considered as the future for energetic materials synthesis
non-acidic nitrating reagents (neutral)
1° amines/nitramines leads to deamination and formation of nitrate ester
by-product but analines are successful.
O O nitronium nitrate salt
N 2 O 5
O
N
O N
[NO + 2 ][NO - 3 ]
O
sublime slightly above rt
condition: chlorinated solvents
- clean and selective
- non-oxidizing &n non-acidic
polar
- adopts two structures
depending on condition
condition: anhyd. HNO 3
- powerful but acidic and non-selective
- 1st prepared over 150 years ago but due to difficult prep and low thermal
stability (require -60 °C long term storage) received little attention.
- Environmental restrictions and push for green chemistry sparked interest
Advantage: Rxns are very clean
- faster and less exothermic (due to absence of oxidation byproducts)
- high yields
- simple isolation
- non-acidic conditions possible with this reagent (compared to mixed acids)
rt
N 2 O Stable for 2 weeks at -20 °C
5 2 N 2 O 4 + O 2
Stable for up to 1 yr at -60 °C
synthesis of TNT under mild conditions
Me
Me
NO 2
N 2 O 5 /HNO 3
32 °C,
quant yield
NO 2
N-nitrations of ureas
H H
N N
HNO 3
O
O
H
N N
2 SO 4
H H
O-nitrations of polyols
HO
OH
OH
OH
OH
O 2 N
O
O 2 N
NO 2
N
N
H
OH N 2O 5 , CCl 4
0 °C
quant yield
NO 2
H
N
N
NO 2
O 2 NO
O
No explosion hazard
HNO 3
P 2 O 5
O
O 2 N
O 2 N
N
N
ONO 2 ONO 2
ONO 2
ONO 2 ONO 2
N
N
NO 2
NO 2
O
Preparation of N 2 O 5 [Deville 1849]
O
AgNO 3 + Cl 2 (g)
O N +
Cl
AgNO 3 N 2 O 5
Dehydration of nitric acid
HNO 3 + P 2 O 5 N 2 O 5 + H 3 PO 4
Δ
N 2 O 4
- isolation by sublimation and collection trap at -78 °C
- stream of ozone needed to avoid collection on N 2 O 4
- if don't care about acidity, can use HNO 3 /P 2 O 5 mixture directly (no ozone stream)
O 3
N 2 O 5
Process chemist at Defense and Evaluation Research Agency (DERA) in the UK
Development of a flow process: Using commercial ozonizer to generate 5 - 10%
mix of ozone in oxygen and mixed in flow with N 2 O 4. N 2 O 5 is trapped in solid
condenser tubes (cooled by dry ice/acetone).
Explosives in JACS: Sila explosives
O 2 NO
O 2 NO ONO 2
- Used in WW I
PETN ONO 2
- Det. Velocity 8,400 m/s
- d= 1.7 g/cm 3
Silicon analogue of PETN
O 2 NO
O 2 NO Si ONO 2
VERY
low e - dens
ONO 2
Klapotke T.M. JACS 2007. 129, 6908
- One of most high energy explosives known
- more shock sensative than TNT. used as booster mix
- Europe marketed as lentonitrat (vasodilator) like NG
"The crystalline compound exploded on every
occasion upon contact with Teflon spatula...
Solutions in diethyl ether exploded upon the slighest
evaporation of the solvent."
Si(CH 2 OAc) 4 Si(CH 2 Cl) 4
Why does Si-PETN have drastically increased sensativity?
Theoretical: electrostatic potential:
1. Surface electrostatic potential, in general, is related to the sensitivity of the bulk
2. The more evenly distributed the electrostatic potential is over the surface of a
molecule, the more stable it is to impact.
O 2 NO
O 2 NO
O 2 NO
VERY high e -
dens
Si
O
N
O
O