1070-4272/05/7808-1218 C 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 8, 2005, pp. 1218!1222. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 8, 2005,
Original Russian Text Copyright + 2005 by Luneva, Petrovskaya, Lyudchik, Ezovitova.
AND INDUSTRIAL INORGANIC CHEMISTRY
Thermal Decomposition of the System CO(NH
in the Presence of Nitrate Compounds
N. K. Luneva, L. I. Petrovskaya, I. A. Lyudchik, and T. I. Ezovitova
Institute of General and Inorganic Chemistry of the National Academy of Sciences of Belarus,
State Research Institution, Minsk, Belarus
Received January 26, 2005
Abstract-Chemical, derivatographic, IR spectral, and X-ray diffraction analyses were used to study thermal
transformations in the system CO(NH
and in the same system with addition of KNO
O, and NH
salts in the temperature range 203600oC. The influence of the chosen nitrate
compounds on the process of reorganization of the constituent ingredients, evolution of nitrogen into the gas
phase, yield of the solid residue, and preservation of nitrogen and phosphorus was revealed.
Recently, nitrogen-phosphorus compounds have
been widely used as cellulose modifiers and combus-
tion inhibitors for various polymeric materials.
The efficiency of nitrogen-phosphorus fire-retar-
dants depends on the chemical nature of the nitro-
gen-containing component, degree of condensation of
the phosphates used, ratio of the main components
(nitrogen to phosphorus), additives introduced, and
some other factors .
It is known that the nature of the metal cation in
inorganic additives present in nitrogen3phosphorus
systems can strongly modify their fire-extinguishing
properties and decomposition temperature [2, 3]. For
example, amidophosphate formulations are effective
fire-protecting means. However, studies of the ther-
mal decomposition of phosphorus-nitrogen mixtures
and of the influence exerted by addition of inorganic
salts on the structural-chemical transformations in
the course of their heating are virtually not reflected
in the literature at all.
Systems composed of a mixture of phosphoric acid
and carbamide, CO(NH
(NP), at a mass
ratio N : P = 1 : 2, and the same formulations with ad-
dition of NH
O, and CsNO
(Table 1) were chosen for study.
The NP systems were prepared by successive in-
troduction of carbamide and appropriate nitrate salts
into phosphoric acid. The content of nitrogen and
phosphorus after thermal treatment was determined
using procedures described in [8, 9].
The X-ray diffraction patterns of the samples stud-
ied were recorded with a monochromatic Cu
tion on an IRS-50M installation, and the IR spectra,
on a Perkin-Elmer instrument by the sandwich tech-
nique  in a polyethylene film in the frequency
range 40033900 cm
. The course of the thermal de-
composition process was recorded with an MOM
Q-1000 derivatograph (Hungary), with temperature
raised at a rate of 10 deg min
in the interval 203
600oC. In view of the fact that vigorous gas evolution
with ejection of the samples under study from cruci-
bles occurred on heating the NP system with nitrate
additives, thermograms were only recorded for the ad-
ditives introduced into the system.
It is known that carbamide forms with phosphoric
acid associates of acid carbamide phosphates [1, 11313].
Table 1. Parameters of the nitrogen-phosphorus compounds
System no. ³ System ³ N
1 ³ NP ³
2 ³ NP3NH
³ 1 : 5.4
3 ³ NP3NH
³ 1 : 2.2
4 ³ NP3LiNO
³ 1 : 9.3
5 ³ NP3LiNO
³ 1 : 3.8
6 ³ NP3CsNO
³ 1 : 11.0
7 ³ NP3KNO
³ 1 : 5.8
is nitrogen contained in an additive.