Comparison of the thermal decomposition behavior for members of the hydroxylamine family

Article abstract of DOI:10.1016/j.tca.2003.09.023

In the present work the thermal stability of some members of the hydroxylamine family was studied using adiabatic calorimetry. The study included aqueous solutions of hydroxylamine free base, hydroxylamine hydrochloride, hydroxylamine sulfate, and hydroxylamine-o-sulfonic acid of concentrations typically used in industry. Also, the catalytic effect of metal surfaces of stainless steel, carbon steel, and titanium was studied. From the solutions studied HA is the most reactive with higher maximum temperature, pressure, non-condensable pressure, and lower time to maximum rate. HA maximum heat rate is at least ～3 times higher than that of the other solutions studied, and the pressure generation rate is ～13 times higher. All decompositions were catalyzed by stainless steel, but only HA was catalyzed significantly by titanium metal. Solid hydroxylamine hydrochloride, hydroxylamine sulfate, and hydroxylamine-o-sulfonic acid exhibited stability up to ～60°C. Hydroxylamine 100% was not studied because it is not readily available, is not used industrially, and is known to be unstable at room temperature. A violent reaction was measured for solid hydroxylamine sulfate that generated a heat rate >500°C/min and pressure rate >5200 psia/min before the sample cell was completely destroyed by the generated pressure.

Full text of DOI:10.1016/j.tca.2003.09.023

Thermochimica Acta 414 (2004) 177–183
Comparison of the thermal decomposition behavior
for members of the hydroxylamine family
Lizbeth O. Cisneros, William J. Rogers, M. Sam Mannan∗
Mary Kay O’Connor Process Safety Center, Chemical Engineering Department, Texas A&M University, College Station, TX 77843-3122, USA
Received 17 April 2003; received in revised form 10 September 2003; accepted 20 September 2003
Abstract
In the present work the thermal stability of some members of the hydroxylamine family was studied using adiabatic calorimetry. The study
included aqueous solutions of hydroxylamine free base, hydroxylamine hydrochloride, hydroxylamine sulfate, and hydroxylamine-o-sulfonic
acid of concentrations typically used in industry. Also, the catalytic effect of metal surfaces of stainless steel, carbon steel, and titanium was
studied. From the solutions studied HA is the most reactive with higher maximum temperature, pressure, non-condensable pressure, and lower
time to maximum rate. HA maximum heat rate is at least ∼3 times higher than that of the other solutions studied, and the pressure generation
rate is ∼13 times higher. All decompositions were catalyzed by stainless steel, but only HA was catalyzed significantly by titanium metal. Solid
hydroxylamine hydrochloride, hydroxylamine sulfate, and hydroxylamine-o-sulfonic acid exhibited stability up to ∼60 ◦C. Hydroxylamine
100% was not studied because it is not readily available, is not used industrially, and is known to be unstable at room temperature. A violent
reaction was measured for solid hydroxylamine sulfate that generated a heat rate >500 ◦C/min and pressure rate >5200 psia/min before the
sample cell was completely destroyed by the generated pressure.
© 2003 Elsevier B.V. All rights reserved.
Keywords: Hydroxylamine; Hydroxylamine hydrochloride; Hydroxylamine sulfate; Hydroxylamine-o-sulfonic acid; Adiabatic calorimetry; Thermal
decomposition
1. Introduction
sulfate, and hydroxylamine-o-sulfonic acid. Hydroxylam-
monium sulfate (hydroxylamine sulfate or oxammonium
sulfate (H2NOH)2H2SO4) is the most common form of hy-
droxylamine used in industry. The commercially available
solutions are 25 mass%, which is close to the maximum
solubility limit at room temperature, and are transported in
stainless steel containers. Hydroxylamine sulfate is also in-
dustrially available as a solid. Hydroxylamine hydrochloride
is also commonly used industrially because hydroxylammo-
nium salts either chloride or sulfates are more stable than
the hydroxylamine free base (solid hydroxylamine free base
is unstable at room temperature). Hydroxylamine-o-sulfonic
acid is used as an intermediate for amination processes.
There exists some information regarding the thermal
stability of hydroxylamine free base solutions [1–4]. In-
formation about hydroxylamine sulfate thermal stability is
scarce with the exception of a DTA study, which reports for
the solid an onset temperature above 138 ◦C accompanied
by gas evolution [5]. Thermal information regarding hy-
droxylamine hydrochloride and hydroxylamine-o-sulfonic
acid is practically non-existent in the open literature [6].
This paper presents thermal hazard information obtained
Hydroxylamine has been involved in two recent fatal in-
cidents resulting in nine fatalities: Concept Sciences, Inc.,
in Pennsylvania and Nissin Chemical in Japan. After those
incidents occurred, the need for thermal hazard information
regarding hydroxylamine and hydroxylamine related com-
ponents became evident. The Mary Kay O’Connor Process
Safety Center is studying thermal hazards associated with
members of the hydroxylamine components alone, in water
solutions of commonly encountered industry concentrations,
and in the presence of some metal contaminants.
2. Background
The components studied were hydroxylamine free base
solutions, hydroxylamine hydrochloride, hydroxylamine
∗
Corresponding author. Tel.: +1-979-862-3985;
fax: +1-979-458-1493.
E-mail address: mannan@tamu.edu (M. Sam Mannan).
0040-6031/$ – see front matter © 2003 Elsevier B.V. All rights reserved.
doi:10.1016/j.tca.2003.09.023

178
L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
under adiabatic runaway reaction conditions. The informa-
tion includes onset temperatures, maximum temperatures,
maximum pressures, non-condensable pressure, time to
maximum rate, heat rates vs. temperature, and pressure
rates vs. temperature. Also, the thermal behavior of aque-
ous solutions in the presence of titanium (Ti) and stainless
steel (SS) metal surfaces are compared, and the effect of
carbon steel as a nail contaminant added to the solutions is
presented.
(FID). The sample size was 0.5 ml for the TCD side and
0.25 ml for the FID side. A Chromsorb 107 (12 feet×1/8 in.,
80/100) and a 13× molecular sieve (6 feet×1/8 feet, 40/60)
columns were used on the TCD side. An alumina plot cap-
illary column (40 m × 0.53 mm × 15 ␮m) was used on the
FID side. Four switching valves were used to facilitate sam-
pling and column selection. The temperature program used
was as follows: 4 min at 35 ◦C, then a 10 ◦C/min ramp until
200 ◦C, and finally 20 min at 200 ◦C. Only the TCD detec-
tor was useful for the particular gas mixture, since no peaks
were detected by the FID.
3. Experimental details
Liquid products were analyzed for ammonia and water.
The ammonia quantification method consisted of adding
MgO to the ammonia-containing sample and titrating the re-
sulting mixture with NaOH with methyl red as an indicator
[8]. The water content of the liquid residue was analyzed
using a Karl Fischer moisture method [9].
3.1. Samples
3.1.1. Solids
The solids studied were Aldrich hydroxylamine hy-
drochloride 99.9999 mass% catalog number 37992-1 [H2
NOH·HCl], Aldrich hydroxylamine sulfate 99.9999% cat-
alog number 37991-3 [(H2NOH)2(H2SO4)], and Aldrich
99.999% hydroxylamine-o-sulfonic acid catalog number
48097-5 [H2NOSO3H].
3.4. Experimental method
The experiments reported here were performed in a closed
cell environment with air above the sample. The heating
mode was heat–wait–search, in which the sample was heated
to an initial search temperature (50 ◦C) and the tempera-
ture was allowed to stabilize (20 min). Then if exothermic
activity was detected, as exhibited by a threshold sample
temperature rise of ∼0.1 ◦C/min, the apparatus followed
the reaction adiabatically until the reaction ended or until
one of the pre-selected safety shutdown criteria was met
(shutdown criteria: temperature 460 ◦C; pressure 10,342 kPa
(1500 psia); temperature rate 400 ◦C/min; pressure rate
∼68,900 kPa/min (10,000 psia/min)). If no exothermic ac-
tivity was detected within 20 min, the sample was heated to
the next search temperature and the procedure was repeated
until a preset maximum search temperature was reached
(250 ◦C).
3.1.2. Aqueous solutions
The solutions studied were Aldrich hydroxylamine
99.999% 50 mass% solution in water (HA) catalog number
46780-4, hydroxylamine hydrochloride/water 35 mass%
(HH), hydroxylamine sulfate/water 25 mass% (HS), and
hydroxylamine-o-sulfonic acid 35 mass% solution in water
(HOSA). All the solutions were prepared from the corre-
sponding solid and Aldrich reagent water catalog number
32007-2. These particular solution concentrations are the
highest industrially available.
3.2. Apparatus
Measurements reported here were performed in an auto-
matic pressure tracking adiabatic calorimeter (ATPAC) [7].
This apparatus permits the measurements of runaway reac-
tion behavior under adiabatic conditions and during an ex-
periment, the pressure inside the sample cell is compensated
with N2 in the space surrounding the sample cell, which can
be made from materials that do not withstand large pressure
differentials such as glass. The data recorded during an ex-
periment are time, temperature, pressure, heat rate, and pres-
sure rate. The APTAC can follow a reaction adiabatically up
to 400 ◦C/min and can compensate pressure increases up to
10,000 psi/min.
Samples were transferred to sample cells using disposable
plastic pipettes. Sample masses were obtained by weight
differences. A sample thermocouple with a Teflon-coated
sheath and a total diameter of ∼1/16 in. was used to prevent
the thermocouple metal surface from contacting the sample,
which may be catalyzed by metals as in the case of hydrox-
ylamine free base [2].
Experimental runs were performed in spherical sample
cells of 130 cm3 nominal volume and of borosilicate glass,
stainless steel 316 (SS), and titanium (Ti). It was presumed
that glass cells provided a neutral environment without sig-
nificant catalysis for the decomposition reactions. Reactivity
with respect to the other materials (SS and Ti) was tested
by using the corresponding cells.
3.3. Analytical methods
Experiments were performed to test the effect of carbon
steel (composed primarily of iron, 97–99%, and graphite,
<2%), which is a common industrial contaminant that is
found in nails, wire, or structural components. A piece of
carbon steel nail (∼0.15 g) was introduced into some sam-
ples after the sample was weighed in a glass cell.
The gaseous products were also analyzed using a gas chro-
matograph (GC), since the possible H2 contained in the de-
composition products cannot be detected in the EI-FTMS.
The chromatograph was a Varian 3400 with a thermal con-
ductivity detector (TCD) and a flame ionization detector

L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
179
Table 2
3.5. Uncertainties
Thermal decomposition rates for some hydroxylamine family members
Samplea
dT/dtmax (◦C/min)
dP/dtmax (psi/min)
A type N thermocouple was used to measure sample tem-
peratures with an overall absolute uncertainty of ∼ 1 ◦C,
and checked periodically at 0 ◦C using an ice bath. Sam-
ple pressures were measured with Sensotec absolute pres-
sure transducers with an overall uncertainty of ∼ 42 kPa
(∼6 psia) and checked frequently for agreement with ambi-
ent pressures. Sample masses were measured with a preci-
sion of 0.01 g.
HA, 50 mass%
HH, 35 mass%
HS, 25 mass%
HOSA, 35 mass%
4.5
0.59
0.11
1.41
1.0
20
1.51
0.32
0.33
3
0.38
0.02
0.67
0.76
0.06
0.32
a
Aqueous solutions.
10
1
HA, 1
HA, 2
HH, 1
HH, 2
4. Results and discussion
HH, 3
0.1
HS, 1
4.1. HA, HH, HS, and HOSA thermal decomposition
behavior in glass
HS, 2
0.01
0.001
HOSA, 1
HOSA, 2
Table 1 presents a compilation of measured parameters
based on an initial solute mass of approximately 1.1 g. With
the exception of HOSA first exothermic activity, HA has the
lowest onset temperature. Analysis of Table 1 shows that,
in the event of a runaway, HA will pose the greatest risk,
since it is able to generate higher temperature, pressure, and
non-condensable pressure.
50
100
150
200
250
o
Temperature, C
Fig. 1. Measured heat rates for some hydroxylamine family members.
and 220 ◦C. For this range of temperature, HA presents the
most aggressive reaction with a heat rate 7.6 times greater
than that of HH, which presents the second most aggressive
reaction. HOSA has its first and most violent exothermic
activity beginning at ∼50 ◦C with a maximum heat rate of
∼1.4 ◦C/min.
A summary of the heat and pressure rates is presented in
Table 2. Information in Table 1 qualitatively suggests that
hydroxylamine free base will release a greater amount of
energy per unit mass, since the adiabatic temperature in-
crease was higher even when a significant amount of the re-
leased heat was consumed to vaporize the solvent and reach
a greater equilibrium vapor pressure. A discussion concern-
ing the heat of hydroxylamine decomposition determined
from the measured heat of reaction and temperature rise is
available in an earlier article [3]. With the additional infor-
mation presented in Table 2, it is evident that not only the
heat released per unit mass of hydroxylamine is greater but
also that it is liberated faster. The rate of energy release is
a critical issue when evaluating thermal hazard; after all, a
runaway reaction is created when the heat produced by the
reaction cannot be removed fast enough by the cooling sys-
tem. Based on analysis of the gas phase decomposition prod-
ucts, an overall decomposition reaction for hydroxylamine
was presented in an earlier article [4].
Fig. 2 presents the pressure rate for the solutions studied.
As shown in this graphic, HA has the greatest pressure rate
followed by HH, HOSA, and HS in that order. It is important
to note that although HOSA was second in the heat gener-
ation rate, it is not second with respect to the pressure gen-
eration rate. This observation can be explained by the fact
that the most aggressive exothermic behavior for HOSA oc-
curs at low temperatures, where the solvent vapor pressure
is low and the produced heat is utilized to heat the sample
instead of vaporizing the solvent. The pressure generation
rate for HA is more than 13 times greater than that of HH.
4.2. Solid hydroxylamine hydrochloride, hydroxylamine
sulfate, and hydroxylamine-o-sulfonic acid thermal
behavior
The heat rate vs. temperature behavior is presented in
Fig. 1, which shows that the studied members of the hydrox-
ylamine family exhibit exothermic activity between ∼100
The thermal analysis of pure hydroxylamine hydrochlo-
ride, hydroxylamine sulfate, and hydroxylamine-o-sulfonic
Table 1
Decomposition parameters for some hydroxylamine family members
Samplea
Ton (◦C)
Tmax (◦C)
ꢀTadb (◦C)
Pmax (psia)
Non-cond. (psia)
tMR (min)
HA, 50 mass%
HH, 35 mass%
HS, 25 mass%
HOSA, 35 mass%
136
145
152
1
10
14
207
185
185
6
8
2
71
40
34
7
4
15
338
99
188
191
41
17
10
22
44
25
10.6
13
5
9
87
101
325
328
35
40
93
51
0.4
<50b, 160
14
90b, 198
5
40b, 40
9
3
a
Aqueous solutions.
Refers to the first HOSA exothermic activity.
b

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L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
100
10
1600
HA, 1
1400
HA, 2
1200
HH, 1
HH, 2
1
1000
800
600
400
200
0
HH, 3
0.1
HS, 1
HS, 2
0.01
0.001
HOSA, 1
HOSA, 2
50
100
150
200
250
Temperature, oC
0
200
400
600
800
1000
1200
1400
Time, min
Fig. 2. Measured pressure rates for some hydroxylamine family members.
Hydroxylamine hydrochloride
Hydroxylamine sulfate
acid produced surprising results, since the least reactive so-
lution, HS, turned out to be the most reactive solid. HS
solutions presented maximum heat and pressure rates of
only 0.62 ◦C/min and 5.39 psi/min, respectively, even when
40 g of HS (10 g of hydroxylamine sulfate) was tested. As
shown in the temperature and pressure profiles of Figs. 3
and 4, respectively, hydroxylamine sulfate has a dramati-
cally more reactive behavior when compared to hydroxy-
lamine hydrochloride and hydroxylamine-o-sulfonic acid. It
is important to note that solid 100% hydroxylamine was
not tested, and, most probably, it would have resulted in an
even more violent reaction than the hydroxylamine sulfate,
because 100% hydroxylamine is known to decompose vio-
lently at room temperature.
Table 3 presents a summary of the decomposition param-
eters for the studied solids. It can be seen from this table that
the hydroxylamine sulfate not only has the highest reaction
onset temperature but also the most violent decomposition.
This observation stresses the importance of experimental
work to test for reactivity, since there is no correlation be-
tween reaction onset temperature and rate of energy release.
Hydroxylamine-o-sulfonic acid
Fig. 4. Pressure profile for some hydroxylamine family members. Solid
100% concentration.
Figs. 5 and 6 present the heat and pressure rates for
the studied solids, respectively. It can be seen that solid
hydroxylamine-o-sulfonic acid has a far more aggressive
heat and pressure generation rates than that of hydroxy-
lamine hydrochloride solid. This is another example of the
importance of experimental work, because behavior in so-
lution cannot be predicted from behavior of the solid.
4.3. HA, HH, HS, and HOSA behavior in the presence of
metals
4.3.1. Nail test
Fig. 7 presents the heat rates produced when a similar
piece of carbon steel in the form of a nail was added to
1000
100
10
1000
900
800
700
600
500
400
300
200
100
0
1
0.1
0.01
0
50
100
150
200
250
300
0
500
1000
1500
Temperature, oC
Time, min
Hydroxylamine hydrochloride
Hydroxylamine sulfate
Hydroxylamine hydrochloride
Hydroxylamine sulfate
Hydroxylamine-o-sulfonic acid
Hydroxylamine-o-sulfonic acid
Fig. 3. Temperature profile for some hydroxylamine family members.
Solid 100% concentration.
Fig. 5. Heat rate for some hydroxylamine family members. Solid 100%
concentration.

L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
181
Table 3
Measured parameters for some hydroxylamine family members
Samplea
Mass (g)
Ton (◦C)
Tmax (◦C)
Pmax (psia)
Non-cond. (psia)
dT/dtmax (◦C/min)
dP/dtmax (psi/min)
Hydroxylamine hydrochloride
Hydroxylamine sulfate
Hydroxylamine-o-sulfonic acid
1.22
1.58
1.58
112
144
71.5
187
NMb
259
139
NMb
74
80.9
NMb
19
0.54
>500
1.28
>5200
3.07
10.4
a
Pure solids.
Not measured due to cell rupture.
b
10000
1000
100
10
1
0.1
0.01
0.001
0
50
100
150
200
250
300
Temperature, oC
Hydroxylamine hydrochloride
hydroxylamine sulfate
hydroxylamine-o-sulfonic acid
Fig. 6. Pressure rate for some hydroxylamine family members. Solid 100% concentration.
HA, HH, and HOSA. Carbon steel catalyzed the three solu-
tions, and the apparent low heat generation of HOSA can be
misleading since HOSA started to react as soon as the nail
contacted the solution, so most of the exothermic behavior
was not measured. In fact, based on what was observed in
the laboratory it is safe to assume that HOSA reacted more
aggressively when contacting the nail than HH and HA. HA
and HH had similar reaction rates but the HA reaction pro-
ceeded for a longer period of time. In the case of HH and
HOSA, the measured heat rates included not only the de-
composition reaction but also the reaction between the acid
media and the carbon steel, since in both cases the nail was
completely dissolved at the end of the experiment.
4.3.2. Test in stainless steel (SS) and titanium (Ti) sample
cells
100
Table 4 presents a summary of the maximum heat rates at-
tained by HA, HH, and HOSA in glass, SS, and Ti test cells.
HS data are not included in the table since no appreciable
exothermic behavior was detected for HS decomposition in
SS or titanium. Table 4 presents also the ratio of maximum
HA with nail
HH-ind with nail
HOSA with nail
HA
10
HH-ind
HOSA
1
Table 4
Maximum heat rate for HA, HH, and HOSA in several test cell materials
0.1
Samplea
dT/dtmax (◦C/min)
(dT/dt)max
/
(dT/dt)max glass
0.01
Glass
SS
77
4.1
27
Ti
SS
Ti
0
50
100
150
200
250
HA, 50 mass%
HH, 35 mass%
HOSA, 35 mass%
4
0.6
1.4
100
19.3
6.9
19.1
25
1
2
Temperature, oC
0.6
3.1
Fig. 7. Heat rate for hydroxylamine solutions with and without carbon
steel in the form of a nail.
a
Aqueous solutions.

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L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
100
10
1
HA in SS
HH in SS
0.1
0.01
HOSA in SS
HA in glass
HH in glass
HOSA in glass
0
50
100
150
200
250
Temperature, oC
Fig. 8. Effect of SS in the decomposition reaction of various hydroxylamine solutions.
100
HA in Ti
HH in Ti
HOSA in Ti
HA in glass
10
HH in glass
HOSA in glass
1
0.1
0.01
0
50
100
150
200
250
Temperature, oC
Fig. 9. Effect of Ti in the decomposition reaction of various hydroxylamine solutions.
heat rate in a metal cell to maximum heat rate in glass. As
can be seen in the table, SS catalyzes HA decomposition as
much as Ti does. For the HH decomposition, there is a sig-
nificant difference between SS and Ti, since Ti has almost
a null catalytic effect, whereas SS increases the maximum
rate almost seven times. For HOSA, SS increases the max-
imum heating rate 19 times and Ti increases the maximum
heating rate 2 times.
Fig. 8 presents the heat rate vs. temperature for the sam-
ples in SS cell. It can be seen that the effect of SS metal
upon contact with HA, HH, or HOSA is to increase the heat
rates. Fig. 9 presents the effect of Ti in the decomposition
reaction of various hydroxylamine solutions. It can be seen
from this graphic that, except for HA, the effect of Ti in
the thermal decomposition in not so drastic as for SS. Ti is
known for its inert qualities so it was surprising to observe
that Ti catalyzes the HA decomposition reaction.
the exothermic behavior of the various hydroxylamine so-
lutions studied [2]. The least reactive substance, HS, has
the highest overall activation energy, but the more reac-
tive solution, HA, has a higher activation energy than HH.
The HA activation energy (28.5 kcal/mol) is lower than
the energy required to break the H2N–OH (61.3 kcal/mol)
bond, so correlations based on the weakest bond break-
age as a way to predict reactivity cannot be applied to
the HA system. The higher dependence of HS decom-
position rate on concentration represented by a reaction
order of two may be due to the presence of two hydroxy-
Table 5
Comparison of kinetic parameters for four members of the hydroxylamine
family
Samplea
Ea (kcal/mol)
p
HA, 50 mass%
HH, 35 mass%
HS, 25 mass%
HOSA, 35 mass%
28.5
25
43
1
0.5
2
4.4. Kinetic comparison
31
0.7
Table 5 presents the activation energy and reaction order
obtained when a power law kinetic model was applied to
a
Aqueous solutions.

L.O. Cisneros et al. / Thermochimica Acta 414 (2004) 177–183
183
Table 6
higher. All decompositions were catalyzed by stainless steel
but only HA was dramatically catalyzed by titanium metal.
Solid hydroxylamine hydrochloride, hydroxylamine sul-
fate, and hydroxylamine-o-sulfonic acid were studied and
all of them were stable up to ∼60 ◦C. Hydroxylamine 100%
was not studied because it is not readily available and is
not used industrially, but it is known to be unstable at room
temperature. Solid hydroxylamine sulfate had a violent re-
action that generated a heat rate >500 ◦C/min and pressure
rate >5200 psia/min before the sample cell was completely
destroyed.
Gas phase analysis for HA and HH
Samplea
N2
(mol%)
NO
(mol%)
O2
(mol%)
N2O
(mol%)
H2
(mol%)
HA, 50 mass%
HH, 35 mass%
70
64.8
4
0.9
–
16.8
24
8.5
2
9
a
Aqueous solutions.
Table 7
Comparison of liquid phase analysis for four hydroxylamine solutions
Samplea
Ammonia
(mass%)
Water
(mass%)
Unaccounted
(mass%)
HA, 50 mass%
HH, 35 mass%
HS, 25 mass%
HOSA, 35 mass%
7.9
4.1
1.8
1.9
92.3
72.4
82
2.8
23.5
16.2
39.1
Acknowledgements
59
We thank CONACYT for its financial support. This re-
search was sponsored by the Mary Kay O’Connor Process
Safety Center at Texas A&M University.
a
Aqueous solutions.
lamine free base molecules in each hydroxylamine sulfate
molecule.
References
4.5. Comparison of the analytical results
[1] H. Surjono, Z. Xiao, P.C. Sundareswaran, Z. Zhe, Understanding
thermal stability of hydroxylamine free base, in: Proceedings of the
218th ACS National Meeting, New Orleans, USA, 1999.
[2] L.O. Cisneros, W.J. Rogers, M.S. Mannan, J. Hazard. Mater. 82 (2001)
13.
[3] L.O. Cisneros, W.J. Rogers, M.S. Mannan, Effect of air in the thermal
decomposition of 50 mass% hydroxylamine/water, J. Hazard. Mater.
95 (1–2) (2002) 13–25.
[4] L.O. Cisneros, X. Wu, W.J. Rogers, M.S. Mannan, J. Park, S. North,
Decomposition products of 50 mass% hydroxylamine/water under run-
away reaction conditions, in: Transactions of the Institute of Chemical
Engineers on Process Safety and Environmental Protection, vol. 81,
Part B, March 2003, pp. 121–124.
[5] J. Ritz, H. Fuchs, Hydroxylamine, in: Ullmann’s Encyclopedia of
Industrial Chemistry, 5th ed., vol. A13, Weinheim, Federal Republic
of Germany, 1985, pp. 527–532.
[6] L.O. Cisneros, Adiabatic calorimetric studies of hydroxylamine com-
pounds, Ph.D. Chemical Engineering Dissertation, Texas A&M Uni-
versity, August 2002.
[7] S. Chippett, P. Ralbovsky, R. Granville, The APTAC: a high pres-
sure, low thermal inertia, adiabatic calorimeter, in: Proceedings of the
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Effluent Handling, 1998, pp. 81–108.
[8] W. Horowitz, Official Methods of Analysis of AOAC International,
17th ed., Method Number 920.03.
[9] W. Horowitz, Official Methods of Analysis of AOAC International,
17th ed., Method Number 966.20.
Gas phase analyses were performed only in HA and HH
samples, and the results are presented in Table 6. As ex-
pected, the HH sample produced more hydrogen. The con-
centration of nitrogen in the gas phase remained almost the
same for HA and HH, but the N2O concentration was lower
in the HH sample. The HH sample produced oxygen that was
not measured in the HA decomposition gaseous products.
Table 7 presents the results for the analysis of the liq-
uid phase residues for the various hydroxylamine deriva-
tives. As shown in the table, all of them produced ammonia.
HA and HH had a higher ammonia mass% than that of HS
and HOSA. For HA the unaccounted for mass% was only
2.8 mass% but for HH and HOSA it was over 20 mass%.
5. Conclusions
From the solutions studied HA is the most reactive having
higher maximum temperature, pressure, non-condensable
pressure, and lower time to maximum rate. HA maximum
heat rate is at least ∼3 times higher than the other solu-
tions studied and the pressure generation rate is ∼13 times