Note: Descriptions are shown in the official language in which they were submitted.
7~
PROCESS FOR DEHALOGENATION OF ORGANIC HALIDES
Polychlorinated biphenyls (PCB) have been identified as
environmental hazards and possible carcinoyens. Thexefore the
manufacture and sale of these materials in some territories,
e.g. North America, is now prohibited. Fluids contaminated in
excess of 25 mg/kg with PCB are considered environmentally
hazardous and need to be stored until such time as a PCB de-
struction facility is available. Considerable resources are
being expended in the containment and monitoring of PCB and
PCB contaminated wastes, both liquid and solid.
Proposed cornbustion methods for waste disposal will, if
adopted, result in the sacrifice of large volumes of oils such
as premium quality insulating oils having an economic value.
There is thus a need for a process which is capable of selec-
tively destroying PCB in oils such as electrical insulatingoils without adversely affecting the important physical and el-
ectrical properties of the oil.
This invention relates to a process for the dehalogena-
tion (destruction) of polychlorinated biphenyls and polychlor-
inated benzenes such as are found in electrical insulating oilscontaminated with compounds generically classified as askarels.
The process of the invention can also be used to decontaminate
PCB contaminated solid wastes using oil as a solvent andtor for
7~
-- 2 --
the destruction oE concentrated PCB waste liquids by dilution
in oil.
The process disclosed hereinafter may more generally be
applied to the dehalogenation and destruction of organic
halides including hazardous halogenated was-tes such as organic
halide-containing wood preservatives and pesticides.
It is known from an article by A.~. Morton et al
"Condensation by Sodium Instead of by the Grignard Reaction
III. Tertiary Carbinols and Acids" JACS, Soc 53, pages 402~
- 4033 (1931) that chlorobiphenyl may be reacted with metallic
sodium, in the form of sodium wire or ribbon, under ice cold
conditions or with gentle warming, in the presence of ethyl
carbonate or ethyl benæoate, with or without additions of ben~
zene, to obtain low or medium yields of biphenylcarbinols.
It is also known from R.L. Menville et al "Determination
of Organic Halides with Dispersed Sodium" Anal Chem 31, pages
1901 - 2 (1959) that organic halides may be reacted with "dis-
persed sodium", (which may be prepared as described in Moeller,
T., ed., "Inorgan:ic Synthesis" Vol V, p.6 McGraw Hill, New ~ork,
1957) in solvents such as benzene, toluene, and xylene, to give
quantitative yields of water-extractable halides.
It has, however been reported by Pytlewski L.L., et al.,
Proc. 6th Annual Symposium on Treatment of Hazardous Waste, EPA
Report EPA-600/9-80-011 (Sept. 1980) that whereas vigorousiy
stirred solutions of sodium in polyethylene glycol dechlorinate
organic chlorides at temperatures above the melting point of
liquid sodium (97.28C), dechlorination does not occur when the
polyethylene glycol is replaced by non-polar, low volatility
~ liquids such as Nujol~a relatively highly viscous non-polar
white paraffinic mineral oil of petroleum origin).
Further it has been reported by Parker D.K., e-t al.~
Unnumbere~ Research Report, G~odyear Tire and Rubber Co.,
7~
~ 3 --
Akron, Ohio, (August, 19~0) that metallic sodium treatment of
heat transfer hydrocarbon oils contaminated by 76 ppm PCB does
not reduce the PCB content below about 49 ppm even after heat~
ing for 6 hours unless the mixture is heated to a tempera-ture
of 300C.
It has now been found that organic halides dissolved in
hydrocarbon-based oils may be effectively dehalogenated at tem-
peratures ranging from about 100C up to about 160~C by main-
taining the solution under agitation in a mixture with a fine
dispersion of molten sodlum particles of which at least 80% are
below 10 microns particle size, whereby the organic halide groups
are reduced to sodium halide.
In the preferred form, the fine dispersion of mol-ten
sodium particles is formed by pre-dispersing metallic sodium un-
der vigorous agitation in a relatively smaller quantity of ahydrocarbon-based oil the same as or compatible with the oil to
be treated, at a temperature above the melting point of sodium
and preferably in the range 105C to 160C, and the pre-disper-
sion is added to the bulk of the oil containing the organic
halide to be dehalogenated.
Of particular interest for present purposes is the treat-
ment of electrical insulating oils contaminated with organic
halides. When the present process is applied to such oils, it
has been found that the resulting reaction mixture, after re-
moval of unreacted sodium, suspended reaction products andsludges and, if necessary, water-washing, drying and activated
clay treatment, has electrical and physical properties which
render it re-usable as electrical insulating oil.
The process is also applicable to other hydrocarbon-based
oils such as turbine oils and crankcase oils. In the case of
treatment of used crankcase oilsl however, the treatmènt is
accompanied by a significant increase in viscosity which ren~ -
ders the application of the process more difEicult.
'7~7~
The present invention will now be more fully described,
by way of example only, with reference to the accompanying
drawings which show schematically one form of apparatus for
carrying out the dehalogenation process.
In order to obtain a satisfactory degree of dehalogena-
tion of the organic halides, it has been found necessary to
react the organic halides wi-th a very fine dispersion of mol-
ten sodium particles. In this very fine dispersion, at least
80~ of the sodium particles should be below 10 microns parti-
cle size. More preferably, at least 90~ of the particles
should be below about 10 microns and at least about 65~
should be less than 5 microns particle size. These very fine
dispersions are best prepared by pre-dispersing sodium at
temperatures above its melting point in a relatively smaller
15 volume of the oil to be treated, or an oil compatible there- _
with and which will not render the eventual product unusable for
its intended purpose. The resulting very fine dispersion is
then blended with a larger volume of contaminated oil, in order
~o provide a reaction mixture containing a desired ratio of
sodium to reducible organic halide. ~ttempts to form the fine
dispersion direct:ly, by vigorous agitation of sodium metal
introduced into t:he bulk of the oil to be treated, are subject
to the disadvanta~e that it may be impossible to form a dis-
persion of the desired degree of fineness without incorporating
excessive quantities of sodium into the mixture, and without
prolonged agitation at very high shear rates, thus leading to
excessive consumption of sodium and wastage of power required
for agitation of the bulk of the oil to be treated.
In the preferred form, in order to form the pre-dispersion~
lump metallic sodium or liquid metallic sodium is added to
dried oil in a quantity suficient to yield a dispersion contain-
ing about 5 to 50~ by weight sodium. The use of less thall about
5% by ~eight sodium is usually inefficient, as then greater
quantities of the pre-disyersion are required to achie~-e the
desired molar ratios of sodium to reducible halogen, while with
7~
~ 5 --
quantities of sodium much greater t]~an abou-t 50%, it is diffi-
cult to achieve a satisfactory dispersion. Preferably, a
weight of sodium sufficient to achieve an about 30% concentra-
tion is employed.
The oil in which the pre-dispersion is to be formed may
be a fresh, uncontaminated oil, or may be oil which is contam-
inated with organic halide material. Desirably, in or~er to
avoid excessive wastage of sodium, the oil is substantially
dry and, if necessary, it is pre-dried either by heating or by
vacuum degassification so that its moisture content is less
than about 100 mg/kg. During the formation of the pre-disper-
sion, the oil is maintained at a temperature above the melting
point of liquid sodium, preferably in the range 105C to 160~C
Below about 105C, there is increased difficulty in obtaining
a satisfactory dispersion, as the sodium particles tend to
agglomerate together to form masses and it may not be possible
to form a dispersion of the desired particle size range even
with prolonged agitation. Temperatures much above about 160C
are undesirable, as there is an increased tendency for degrad-
ation of the oil through thermal cracking and oxidation. Pre-
ferably, the dispersion is formed at a temperature o~ about
120C.
The vessel in which the dispersion is formed, and all
other vessels and processing equipment subsequently employed
in the process with which the metallic-sodium-containing mix
tures come into contact, are desirably formed or are lined
with materials inert with respect to liquid sodium e.g. mild
steel, stainless steel, or glass.
The mixture of sodium and oil is subjected to vigorous
agitation for a period sufficient to produce a fine sodium
dispersion of the required particle size distribution. The
particle size distribution of the resulting dispersion can
be readily determined usiny conventional optical particle
counter apparatus, for example a HI-~C ITrade Mark) machine
7~7~
-- 6 --
ancl the conditions of agitation and period of time required to
produce the desired particle si~e distribution can be readily
determined in any given case by trial and experiment. By way
of examplel it may be mentioned that in the case oE disperslons
containing 5 - 50~ by weight sodium, a satisfactory dispersion
may be obtained after 10 - 15 minutes agitation in a modiEied
one litre WARING (Trade ~ark) blender utilizing a bottom drive
four blade impeller operated at 20,000 rpm. Alternatively, a
top drive impeller equipped with either a Cowles Dissolver
(Trade Mark) head or a Premier Mill Dispersator (Trade Mark)
head may be used.
As noted above one preferred class of oils to be treated
by the present process are contaminated electrical insulating
oils. The properties of oils which are designated as "elec-
trical insulating oils" are well understood by those skilled inthe art, and one skilled in the art can readily determine
whether or not a given oil is an electrical insulating oil.
For the avoidance of doubt, as used herein the term "electrical
insulating oil" refers to mineral electrical insulating oils of
pe~roleum origin for use as insulating and coolin~ media in
electrical power and distribution apparatus such as transfor-
mers, regulators, reactors, circuit breakers, switch gear, and
attendant equipment.
Desirably, electrical insulating oil should conform to the
specifications set out in Table 1, as determined by the rele-
vant ASTM test procedures. Preferably, the oils employed in
the present process conform to these specifications.
TABLE 1
Dielectric strength - more than 20 kv ~at water
(ASTM D 877) content less than 20 mg/kg)
Relative density at 15C - 0.8 to 0.92
(ASTM D 1298)
Pour Point - -60C -to -10C
'7'~
-- 7
Viscosity at 40C - 8 to 14 centistokes
(ASTM D 445)
Flash point - 140 to 200C
(ASTM ~ 92)
A Eurther example of a class of oils which may be treated
by the present process is turbine oil. These are usually
sulfur-free mineral oils of petroleum origin employed as a lub-
ricant medium in steam turbines, electrical generators and
other rotating equipment systems. Preferably, the turbine oils
conform to the specifications set out in Table 2.
TABLE 2
Pour Point -40 to 0C
Viscosity at 40C
(ASTM D 445) 25 to 70 centistokes
Flash Point
(ASTM D 923 180 to 250C
A further example of a class of oils to which the process
may be applied i5 crankcase oil i.e. oil used as internal com-
bustion engine lubricant. Preferably, these conform to the
specifications set out in Table 3.
TABLE 3
Viscosity at 100C
(ASTM D 445) 4 to 20 centistokes
Viscosity at -18C
(ASTM D 445~ ~ 9600 centistokes
Flash Point
(ASTM D 92) 150 to 240C
Pour Poin~ -50 to -5C
The dehalogenation of organic halides by fine liquid
sodium particles does not occur satisfactorily in silicone-
based electrical insulating oils and therefore in -the present
process hydrocarbon-based oils are employed.
7~
-- 8 --
In one e~ample of a process in accordance with the invention,
as illustrated in the accompanying drawings, PCB-con-taminated
electrical insulating oil or other hydrocarbon-based oil -to be
treated is stored in a storage vessel 10 from which a batch of -the
oil is transferred by a pump Pl along a line 11 to an enclosed
reactor vessel 12 preferably of steel. The vessel 12 is equipped
with a low speed impeller 13, heaters 14, and an exhaust condenser
16. A line 17 is provided connected to a cylinder 18 of nitrogen
or other inert gas which is slowly bubbled into the mixture to
exclude air and form a blanket of inert gas to reduce losses of
the subsequently-introduced sodium through oxidation. The
condenser 16 removes organic vapours from the exhaust nitrogen or
other inert gas To avoid excessive production of hydrogen gas on
addition of the sodium, and to avoid excessive sodium consumption,
the oil in the storage vessel 10 is desirably pre-dried, if
necessary, to less than 100 mg/kg water either by heating or by
vacuum degassification.
With the batch of oil in the vessel being maintained under
moderate stirring sufficient to ensure intimate mixing and to
preven-t settling of the sodium dispersion, the pre-dispersion,
prepared as described above is introduced into the reactor
through a line 19.
Before the introduction of the suspension, the oil contained
within the reactor vessel 12 is heated to a temperature in the
range of 100 - 160C. At temperatures below 100C, the reaction
times needed for substantially complete reduction of the organic
halide groups to sodium halide tend to be excessively long, and
there is a risk of the liquid sodium particles tending to
agglomerate together to form agglomerated masses. It is important
that the dispersion of sodium particles should remain in the form
of dispersed particles of fine particle size, as wi-th particles of
greater size, the reaction is much less effective. Without
wishiny to be bound by any theory, it is believed that the
reduction in -the rate and efEiciency of the dehalogenation process
7 9~
_ 9 _
with particles o~ increased size is due to the coating of such
large particles by reaction products thus hindering or preventing
~urther reaction. In any event, it is -found that with larger
sodium particles, for example of 100 microns particle size, the
dehalogenation process is mu~h less effective. The use of a
dispersion such that at least 80% of the particles are below 10
microns particle size, more preferably with at leas-t about 50% of
the particles below about 5 microns particle size, is a hiyhly
important factor in obtaining a satisfactory dehalogenation
reaction. The oil in the reactor vessel should not be heated to
temperatures much in excess of about 160C, as at higher
temperatures t.here is increased risk of degradation of the oil
through thermal cracking and oxidation. Preferably, the reaction
mixture is maintained at a temperature of about 110C to about
130C.
Preferably, sufficient of the dispersion is added through the
line 19 to the batch of oil isolated in the reactor 12 to provide
in the reaction mixture a molar ratio of sodium to reducible
chlorine in the range about 2:1 to 30:1. Below this range of sodium
contents, satisfactory dehalogenation is not likely to be achieved,
while contents of sodium higher than the above mentioned range do
not appear to add to the effectiveness of the reaction and merely
result in excessive consumption of sodium. In the most preferred
form, the molar ratio of sodium to reducible halogen is at least
about 4:1, and more preferably is about 4:1 to about 8:1.
Although oil solution containing greater than 10% by weight
of dissolved halogenated species can be treated by the present
process, greater quantities of the sodium dispersion need to be
added to the oil and this may render it more difficult to maintain
intimate mixing of the stirred reaction mixture. It is therefore
normally preferred to employ oils containing no more than about
10~ by weight dissolved halogenated species. In the preferred
form, the organic halide is a PCB and is present in the oil in an
amount of at least about 25 mg/kg, more preferably at leas-t about
100 mg/kg. Employing the present process the oil can be sub-
> -- 10 --
stantially wholly dehalogenated to achieve final concentrations
of organic halide species of less than about 5 mg/kg, more
usually less than about 2 mg/kg wi-thin about 15 to 240 minutes.
In the preferred form, the dehalo~enation is comple-te in less
than about 30 minutes.
On completion of the reaction, the ~eaction mixture is
pumped by a pump P2 along a line 21 to a solids-liquids separa-
tor device, for example a centrifuge Cl. Desirably, a centri-
fuge capable of maintaining a minimum relative centrifugal force
of 210 G at the periphery of the centrifugal plates is employed.
At -the centrifuge Cl, the solids i.e~ unreacted sodium, suspen-
ded reaction products and sludges are removed from the oil. The
removed solids are passed along a line ~2 and are collected in a
collection vessel 23. If desired, the solids collected in the
15 vessel 23 may be subjected to a conventional treatment for re- _
covery of metallic sodium therefrom before being disposed of as
waste.
The liquids separated at the centrifuge Cl may be passed
along line 25 to a quenching vessel 24 where any remaining tra~
ces of sodium are quenched with water introduced through a line
26. If the oil has not cooled sufficiently through its passage
through the centrifuge Cl, it is permitted to cool below about
95C before contact with the water, to avoid excessively vigor-
ous reaction. In the vessel 24, the mixture of oil and water
is maintained under agitation by a stirrer 27, and the oil is
washed free of any remaining traces of sodium and of soluble
reaction products such as sodium halide and sodium soaps of
acidic oil components. The oil and water mixture is pumped by
a pump P3 along a line 28 to a further centrifuge C2 where the
heavier water phase is separated from the oil and collected in
a waste water collection vessel 29.
The oil phase may be subjected to further washing stages
and in such case is passed successively throu~h a series of
washing tanks, similar to the quenching tank 24, where the oil
'7'7~
-- 11 --
phase is mixed with water, and the oil-water mixture Erom each
tank is passed through a centrifuge similar to the centrifuge
C2 be~ore passing to the subsequent washing tank. ~ single
tank 24 for quenchiny and washing, and centriEuge C2, are suf-
ficient for all washing stages if the oil phase is xeturnedto the washing tank 24 through a return line af-ter passing
through centrifuge C2 The oil may be washed with a total
volume of water appro~imately equal to that of the volume of
the oil, and the washing may be conducted in 3 to 5 separate
stages. As shown in the accompanying drawings, the first wash-
ing stage in the tank 24 is desirably performed under a blanket
of inert gas supplied along line 31 from the inner gas container
18, or may be conducted under copious air flow, to ensure that
any hydrogen evolved in the reaction of sodium with water in the
tank 24 is diluted to less than the lower explosive limit for
hydrogen, more preferably to less than about one-fifth the lower
explosive limit. Instead of subjecting the oil-water to centri-
fugation after each washing stage, the mixture may instead be
allowed to settle into distinct oil and water phases and the oil
phase pumped off.
The gases evolved from the reactor vessel 12 and the quen-
ching vessel 24 (mainly inert gas containing some hydrogen) are
collected beneath exhaust hoods 32 and may be vented to the at-
mosphere.
After washing, the oil is passed along line 33 to a storage
tank 34. The washed oil is substantially free of halogen and
halogenated compounds, but contains some dissolved water. The
oil can be dried by pumping it by a pump P4 along a line 36 and
filtering it through blotter type paper in a filter press 37 or
3Q by vacuum drying. The dried oil is collected in a vessel 38.
If necessary or desirable, the quality of the oil product may
be further improved by filtering it through a column of acti-
vated clay to remove trace impurities.
y~
- 12 -
The process described above may be modified by eliminating
the quenching, water-washing and drying steps, without affecting
the quality of the product if the solids separa-tion step is car-
ried out efficiently. In such case, any remaininy sodium or
suspended solids present in the product can be removed by ac-ti-
vated clay trea-tment.
Some detailed Examples of the present process will now be
given.
EXAMPLE 1
Sodium Dispersion Preparatio
25 g of lump sodium metal at 23C is added to the stainless
steel mixing bowl of a 1 L capacity Waring Blender containing
300 g of an electrical insulating oil meeting standard specifi- _
cations for new electrical insulating oil. The oil is at a tem-
perature of 120~C~ A nitrogen gas flow of approximately 60
ml/min is establislled over the oil to provide an inert atmos-
phere, preventing oxidation of highly reactive sodium and the
mixture is blended for 15 minutes at a controlled temperature of
122.5 ~ 2.5C and impeller speed of 20,000 RPM. The resulting
mixture is a uniformly grey dispersion of spherical particles
with particle size distributed as shown in Table 4.
The concentration of sodium in oil may be varied from about
5% to about 50% by weight.
TABLE 4
Sodium Particle Distribution Data
Particle Number
Diameter Average of
Range Particles in
(~m~ Range (%
30 ~3 40
3-5 25
5-9 19
g-ll 1~
11-15 3.4
3515-30 0.6
- 13 -
The extreme ~ineness of the dispersion (65% of particles
less than 5 ~ diameter and 96~ less than 11 ~m diameter) will
be noted.
EXAMPLES 2 to 16
Dechlorination of Chlorinated ~romatics with Sodium Disl~_rsion
_
Freshly prepared sodium dispersion prepared as described
in Example 1 is used to dechlorinate several chlorinated com-
pounds, intimately mixed with insulating oil, in a 1 L glass
reactor consisting of a standard 3-necked flask equipped with a
sealed stirrer, nitrogen gas input/output connections, four
equally spaced 1/2" glass baffles and an electric heating ~an-
tle. Reaction conditions and results for a variety of dechlor-
inations are given in Table 5.
The results obtained are repeatable and consistent when
using dispersions prepared in the manner disclosed above. Lar
ger sodium particles, for example 100 ~n particles, are much
less effective in promoting dechlorination and coating of such
large particles by reaction products is suspected. The sodium
particle size is thus an important factor in the efficient de
c~lorination o PCB by molten sodium.
In example 16, the dechlorination was conducted on an oil
sample containing an oxidation inhibitor, showing that the
presence of oxidation inhibitor does not interfere with the
dechlorination process.
EXAMPLES 17 to 19
Dechlorination of PCB and Chlorinated Benzenes with
Sodium Dispersion
,
PCB contaminated insulating oil is treated in a 205 L re-
actor system according to the method described above in detail
with reference to the accompanying drawings. Oils used are ob-
tained from segregated stocks of PC~ con-tamina-ted insulating oil
from Ontario Hydro storage~ These stocks are contaminated wi-th
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- 16 -
Arochlor ]260 (hexachlorobiphenyl~ and polychlorinated benzenes.
The results of three typical reactions usiny a batch size
of 120 L are ~iven in Table 6. In all cases, PCB and chlorin-
ated benzenes are effectively destroyed in the reaction step.
The efficiencies of the dechlorina-tions are more than -twice
-those of the laboratory scale tests obtained in Examples 2 to
16 and it appears this is because at larger scale operation
there is reduced air oxidation of the sodium and more effective
contact of reactive sodium with the chlorinated organics.
Oil Reclamation
To determine the overall effect of the PCB dechlorination
reac-tion, water washing, and clay treatment on oil quantity,
standard electrical insulating oil acceptance tests were per-
formed on untreated, PCB-dechlorinated and final clay-treated
oils. The oils used in these tests were obtained as follows:
(l) The untreated oil sample was new insulating oil meet-
ing a standard electrical insulating oil specification
~Ontario Hydro specification M-104M-79).
(2) The PC'B dechlorinated oil sample resulted from treat-
ment of 500 mg/kg Type D askarel in untreated oil with
sodium followed by water washing and filter drying as
described in detail above with reference to the draw-
ings or by vacuum drying.
(3) The clay treated oil sample was obtained by agitating
1% by weight Fullers Earth with PCB dechlorinated oil
at 70C using a laboratory bench stirrer for 1 hour.
- The results for the untreated, PCB-dechlorinated and clay
treated oils are compared to new oil acceptance requirements in
Table 7. Some of the quality tests were repeated after oxi-
dation stability testiny which consisted of subjecting the oil
to oxidizing conditions effective to remove oxidation stabili-
sers from the oil. After PCB dechlorination, the power factor,
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TABLE 5
OIL QUALITY TESTS
Test Reference Requirements Untreated PCB Final
tASTM) ~Ontario HydroOil Dechlorinated Clay
M104-79)Sample SampleTrOailed
. ~ . _ ._ _ . . _
Steam Emulsion D1935 Max 60 25 63 59
Number (S)
Water Content _ * 36 48 44
~mg/kg)
PCB Content OH Test 2 2 2 2
(mg/kg)
Power Factor D924 Max 0.5 0~48 0.6~ 0.12
@ 100C ~%)
Dielectric D877 Min 26 32 16 33
Strength (kV)
Neutrallzation D974 Max 0.03 0.01 0.01 0.01
Number (mg ~OH/g)
Interfacial D971 Mln 35 44 40 48
Tension (mN/m)
Relative Density D1298Max 0.906 0.861 0.860 0.860
@ 15C
ASTM Colour Value D1500 Max 1 1.0- 2.0- 1.5
Pour Point (C) OH Test Max -46 -46 -46 -46
Viscosity @ D445 Max 10 9.0 9.2 9.1
37.8C ~mm~/S)
Flash Point (C) D92 Min 146 157 157 157
Fire Point (C) D92 * 174 168 168
Oxidation D2440 Pass Pass Pass Pass
Stability
Results After
Oxidation
Stability Test
Neutralization D974 Max 0.10 0.10 0.01 0.01
Number (mg ~O~/g)
Interfacial
Tension (mN/m) D971 Min 20.0 36.5 33.0 38.0
Sludge Nil Nil Nil Nil
ASTM Colour Value D1500 2.5- 3.5- 2.5
.. _
* Not a requirement for acceptance.
7~
- 19 -
steam emulsion number, dielectric streng-th and colour value did
not meet the requirements for new oil. Following clay treat-
ment only the colour value failed to meet -the new oil requixe-
- ment. The high colour value is not considered significant
since the oil passed the tests for pour point, power fac-tor,
dielectric strength, oxidation stability, and steam emulsion
number. The final clav treated oil is considered suitable for
use in transformers and other electrical equipment requiring an
oil meeting standard specifications e.g. Ontario Hydro Specifi-
10 cation M-104-M79 and/or CEA Standard C-50.
Examples 20 and 21
The process generally as described in Example 2 was re-
peated using PCB-contarninated turbine oil. The results are as
indicated in Table 8.
TABLE 8
_ ~ _ _
Initial Reaction ~Reaction Sodium/Chlorine ¦ Final
PCB TimeTemperature ratio l PCB
Content(hours) ~C) (mole/mole) ¦ Content
(mg/kg) _ I (mg/kg3 ¦
20650 1 120 16/1 45
650 1 _ 140 16/1 ~2
_
Example 22
-The process generally as described in Example 2 was re-
peated using a PCB-contaminated used crankcase oil. The re-
sults are shown in Table 9.
TABLE 9
Initial Reaction Reaction Sodium/Chlorine Final
PCB TimeTemperature ratio PCB
Content (hours) (C) (mole/mole) Content
30(mg/kg) (mg/kg3
__ _ __
680 1 1~0 16/1 29
7~
~ 20 ~
'~he results show that a siyniEicant decrease in the organic
halide content was obtained, but the increase in viscosity made
it difficult to maintain adequate stirring of the reaction mix-
ture and continue the reaction. Continued reaction using the
same equipment, to ob-tain a product with a reduced PCB con-tent
which could be sa~ely disposed of, could be obtained by using as
a diluent other oil less suscep-tible -to an increase in viscosity
under the reaction conditions~ Al-ternatively, the reaction could
be carried out using equipment such as a roller mill in which
continued agitation o~ the reaction mixture would not be hindered
by the viscosity increase.
