Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 8, pp. 1450−1453.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
A.A. Fedorov, Yu.S. Chekryshkin, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 8, pp. 1344−1347.
Oxidative Degradation and Pyrolysis of Polyvinyl Chloride
in Binary Mixtures
of the System K, Na, Ca || NO
A. A. Fedorov and Yu. S. Chekryshkin
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences, Perm, Russia
Received March 10, 2010
Abstract—Oxidative degradation and pyrolysis of polyvinyl chloride in the temperature range 200–500°С in
binary mixtures containing sodium, potassium, and calcium nitrates and nitrites and calcium hydroxide were
studied. A scheme of oxidative degradation of polyvinyl chloride and of binding of chlorine and carbon present
in the polymer in the reactions of the degradation products with the mixture components was suggested.
Polyvinyl chloride (PVC) plays a key role in
production of plastics for already more than 40 years
and occupies the second place in the production volume
after polyoleﬁ ns. Its use involves formation of enormous
amounts of wastes. In West Europe, the amount of
polyvinyl chloride in municipal wastes is estimated at
approximately 2 million tons annually .
Incineration of municipal wastes became an alterna-
tive to their dumping. At the same time, incineration
processes and especially uncontrolled incineration of
wastes lead to formation of harmful substances, e.g.,
carbon black, smoke, dioxins, acid gases, heavy metals,
aliphatic and aromatic compounds [2–5].
Wastes of synthetic polymeric materials are most
frequently processed by pyrolysis , which is usually
performed in an inert atmosphere or in a vacuum with
the formation of various chemically or energetically
valuable gaseous and liquid hydrocarbons. More
seldom, the process is aimed at production of carbon
and graphite .
The possibility of using molten salts as a medium in
pyrolysis was established for the ﬁ rst time in utilization
of automobile tires . Already the ﬁ rst results showed
that the reactions in the majority of salts are very fast.
About 90 vol % of gases formed in pyrolysis was
evolved during the ﬁ rst 400 s at 450°C . The yield
of hydrocarbons and gas with molten salts used as
a pyrolysis medium in tire utilization is comparable with
their yield in a rotary kiln for pyrolytic reclaiming at
temperatures of approximately 700°C .
The most widely used media in pyrolysis are alkali
metal carbonates and chlorides and their eutectic
mixtures. To determine how the nature of the melt affects
the regeneration of hydrogen present in wastes and the
nature and rate of formation of pyrolysis products,
Chambers et al.  studied utilization of the organic
part of spent automobile tires in binary and ternary
chloride eutectic mixtures LiCl–KCl, KCl–CuCl,
, LiCl–KCl–CuCl, ZnCl
–KCl, and ZnCl
at 380–570°С . With
increasing temperature, the yield of methane increased,
whereas the yield of C
hydrocarbons decreased. The
yield of the gas was higher in more acidic melts such
. Hydrogen was the limiting factor in
reactions in which the residue was carbon. The most
efﬁ cient hydrogen conversion was observed with the
KCl–LiCl melt containing 10% CuCl. The nature of
products and amount of hydrogen remaining in the
products depend on the nature of salts whose melt is used
as pyrolysis medium. The same conclusion was made by
Bertolini and Fontaine , who studied the pyrolysis