Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates to a dispersing agent for
solid hydrophobic coal particles dispersed in water, and more
specifically use thereof for dispersing coal particles in water.
Crude tall oil is obtained as a by-product in the raft
or sulfate pulping process. The black liquor separated from the
pulp contains sulfate soap. By separation of this soap and
splitting thereof by acidification crude tall oil is formed. The
splitting normally is effected with sulfuric acid. There are,
however, other reactions than splitting of sodium soaps of fatty
and rosin acids taking place e.g. esterification and
sulphonation. This is apparent from the fact that tall oil split
with sulfuric acid will have other characteristics than tall oil
being split with weaker acids. The expression crude tall oil in
this connection also comprises the extractive material produced
in the sulfite pulping process.
Crude tall oil consists of fatty colds, rosin colds and
neutral substances. The fatty acids are a mixture of oleic acid
and linoleic acid comprising smaller amounts of other saturated
and polyunsaturated acids, The rosin acids are diterpenes with a
cyclic, rigid, hydrophobic part. The neutral part of the crude
tall oil mainly consists of polycyclic hydrocarbons, strolls and
other high molecular alcohols such a a-sitosterol, battalion and
long chain fatty alcohols. The amount of neutral part depends on
the wood furnish, pine giving about 10~ neutral substance and
birch just below 30% neutral substance of the extractive
material.
The main part of the crude tall oil being produced is
.,",~
., I,.
2 ~23~32
further refined by fractionated distillation, tall oil
head, tall oil fatty acid/ tall oil rosin acid and pitch
being obtained as different fractions. The economy of this
process depends on the composition of the tall oil. Thus
in turn depends on the composition of the wood furnish
to the sulfite pulping industry. Some crude tall oils
have a composition that makes them economically unfeasible
for distillation. The increased proportion of birch and
the decreased proportion of pine during the last years
have resulted in that tall oil of the kind not being
distillable has become more common. The producers have
difficulties in selling this crude tall oil and it is
in some cases burnt.
The composition of distillable crude tall oil normally
is within the following limits:
Acid value: 120 - 170
Fatty acid content: 32 - 55%
Rosin content: 11 - 50%
Unsaponifiable: 5 - 24%
.
A typical Scandinavian crude tall oil has the following
values:
Acid value: 143
Rosin content: 30%
Unsaponifiable: 15%
Variations in the tall oil depend on which trees are
used in the pulp process as well as where they have been
growing. A pulp digested on birch alone give about 70%
fatty acids and 30% unsaponifiable. Rosin acids do only
exist in coniferous trees.
Uncharged particles of a colloidal size, that is smaller
3 ~23~L~33;~
than about 0.1 em, as well as larger particles, so-called
coarse disperse particles, have a tendency to agglomerate
in solution forming particle aggregates This can be pro-
vented-in accordance with known principles, Ida. by -
starkly or electrostatically stabilization of the par
tides. In starkly stabilization by means of polymers
the polymer molecule is absorbed to the particle surface.
It is known since long that the best polymers for this purpose
should have one part having a high affinity to the dispel-
soon medium and another part being attracted to the particulate is also known that the addition of substances having
ionic groups, such as polyelectrolytes, increases the
stability of the dispersion. For larger particles, which
settle under the influence of gravity, a stabilization
against sedimentation is in also required
In US-A-4 358 293 there is thus disclosed a dispersion
of coal particles in water, wherein as dispersing agent
is used a non-ionic surfactant polyalkylene oxide compound
having a hydrophobic portion and a hydrophilic portion,
and wherein the hydrophilic portion comprises at least
100 units of ethylene oxide
It also known from the SE-patent application 8104645-0
to disperse coal particles in water by means of several
different additives, such as a tensile which is absorbed
to the particle surface causing repulsion between the
particles, and interacting hydrophilic polymers which are
supposed to provide starkly hindrance.
SE-patent application 8301502-4 finally, describes a
dispersing agent for coal particles in water being obtained
by esterification of tall oil pitch with polyalkylene
glycol.
Tall oil fatty acids and tall oil rosin acids as well, can be
reacted with for instance polyethylene glycol to form
products having dispersing characteristics. A partial
~31~)3~
esterification of crude tall oil with polyethylene glycol or
polyethylene glycol derivatives during heating will give a disk
pursing agent for solid hydrophobic particles in water. This
substance has substantially better characteristics compared to a
tall oil fatty acid esterified with polyethylene glycol during
the same conditions as to the ability to produce a particle disk
pension having a high solid proportion and a liquid flow.
It has now been found that an improved dispersing agent
for coal particles in water is obtained if the viscosity of the
crude oil is increased, that is a molecular enlargement is
achieved before the esterification. A polymerization of the
different components of crude tall oil, such as fatty acids,
rosin acids and fatty or rosin acid derivatives, also gives
products with enlarged molecules, which can be used to prepare
improved dispersing agents.
The fatty acid could be saturated or unsaturated and
should have at least 10 carbon atoms, preferably at least 16 car-
bun atoms. As examples of fatty acids can mentioned palmiticacid, Starkey acid, oleic acid, linoleic acid, linolenic acid,
pinolenic acid.
According to the present invention there is provided a
coal-water dispersion comprising coal particles dispersed in
water and a dispersing agent in an amount of 0.01-5% by weight of
the dispersion, wherein the dispersing agent is a partial ester
of dim Eric, trim Eric or oligomeric fatty acid-containing compost-
lion selected from the group consisting of: (a) a crude tall oil
having been polymerized so that its viscosity at 50C has been at
least doubled; (b) a polymerized fatty acid compound; and (c)
residue obtained in distilling fatty acids from fats or oil,
which composition has been partially esterified with a polyalky-
tone glycol compound having an average molecular weight of at
least 4,000 and mainly being composed of ethylene oxide units,
said dispersing agent having a residual acid value higher than 3.
~l~31~3~:
The dispersing agent of the invention is a partial
ester of a dim Eric, trim Eric or oligomeric fatty acid-containing
composition selected from the group consisting of: (a) a crude
tall oil having been polymerized so that its viscosity at 50C
has been at least doubled; (b) a polymerized fatty acid compound;
and (c) a residue obtained in distilling fatty acids from fats or
oil, which composition has been partially este~ified with a
polyalkylene glycol compound having an average molecular weight
of at least 4,000 and mainly being composed of ethylene oxide
units, said dispersing agent having a residual acid value higher
than 3.
Polymerized fatty acid refers to a diver, triter or
oligomer product obtained by polymerizing one or several differ-
en fatty acids. The diver fatty acid will produce a well per-
forming dispersing agent.
The polymerized fatty acid compound comprises for
example a fatty acid polymerized with a
\ - pa -
:1~3~32
rosin acid or any other compound and a polymerized
mixture of different fatty acids, rosin acids and/or
higher alcohols or other neutral substances.
A preferred dispersing agent of the invention is crude
tall oil, which has been polymerized so that its viscosity
at 50C has been at least doubled, and partially esterifi- -
Ed with a polyalkylene glycol or monster or monoether
thereof, having a residual acid value higher than 3.
1 0
An increase of the average molecular weight of the crude
tall oil or the compononents thereof effect the properties
as dispersing agents after the partial esterification
with the polyethylene glycol. The reason for this is that
a just large enough hydrophobic unit to which different
types of hydrophilic groups as acid and hydroxyl are linked
is desirable. To the carboxylic acid groups polyethylene
glycol chains are added. The molecule so formed is to have
adequate characteristics as to the interaction with
water to be able to serve as a dispersing agent, that is
a nominally water insoluble part adsorbing to the hydra-
phobic surface and a nominally water soluble Hart strongly
interacting with water. The molecule so adsorbed on the
particle will thus give a starkly protection by means
of the polyethylene-glycol chains as well as an electrostat-
teal one by means of the groups being charged in neutral
phi These two protective mechanisms counteract a particle
aggregation due to the attractive forces (Van de Weals)
between the parties. The size of the hydrophobic as well
as of the hydrophilic part is of importance for the extent
of well performance of a dispersing agent. It is known
form the literature that the ability of a polyethylene
oxide chain to give starkly protection depends on its
length. The size and the type of hydrophobic part
also effect the adsorption of the dispersing agent from
the water solution to to particle surface.
~:3~L~)32
An increase of the average molecular weight is reflected
in an increased viscosity there is, however, no linear
connection.
It has been found that a viscosity of the crude tall oil
at 50C above 1000 mPa.s,determined on an Emil rotation
viscosimeter (Respirator A/S, Denmark gives an improved
dispersing ability. -
.
1 0
It is also of importance that the residual acid value
of the product obtained is higher than 3, that is that
there are a sufficient number of free acid groups left
after the reaction, as these groups contribute to the
electrostatic repulsion between the particles to be disk
pursed. Products having a residual acid value lower than
and about 3 have clearly inferior proper its compared
to corresponding products having a higher residual
acid value. A residual acid value within the range 5 - 12
seems to be adequate.
Crude tall oil can be polymerized in accordance with
several known processes. In heating crude tall oil,
optionally in the presence of catalysts, reactions take
place which among other things bring about an increase
of the viscosity. An example of the chemical reactions taking
place-is esterifica~ion, that is the reaction of the acid
groups with alcohols, which are both present in the crude
tall oil. This reaction is catalyzed by strong acids such
as sulfuric acid, residues of which are present in the
crude tall oil from the splitting step. Crude tall oil
has a hydroxyl value of about 25 due to the free alcohols,
and these hydroxyl groups are in principle removed by
reaction during the polymerization.
7 I 2
Diets- Alder reactions between molecule shaving isolated
an conjugated double bonds also take place. The proper-
lion of conjugated double bonds is of critical importance
for the amount of product being formed by the Diels-Alder
reaction. The conjugation of isolated double bonds is
catalyzed by anthraquinone, which is present in the crude
tall oil when this chemical has been added to the digester
in the sulfite pulping industry. According to an embody-
mint of the invention the dispersing agent it based on fatty
or rosin acid derivatives, which are derived prom fatty
or rosin acids containing conjugated double bonds which
have been reacted according to Diels-Alder in order to
increase the number of caboxylic acid groups.
Oxidative polymerization also takes place in crude tall
oil. This refers to such reactions between oxygen and
olefines resulting in the formation of a high concentra-
lion of free radicals. This type of polymerization ox crude
tall oil is consequently facilitated by supplying air.
! Boron trifluoride is a strong Lewis acid. From literature
BF3 is a known polymerization reagent for compounds come
prosing double bonds, for instance vegetable and animal
oils. Terrapins too, as I- and pinion, dipentine, skyline
can be polymerized with BF3. The reaction between Patty
and rosin acids respectively and BF3 is known from
literature. Reactions with alcohols can also be accomplish-
Ed by means of BF3.
. .
The viscosity of crude tall oil can also be increased
by adding multi functional alcohol and acid during heating.
Jo
According to another embodiment of the invention the disk
pursing agent is based on fatty Reagan acid derivatives
derived from fatty ooze Lo acids which have been reacted
with a multi functional alcohol and/or carboxylic acid.
Suitable polybasic acids are chiefly malefic android, phthalic
android- isophthalic android, trimellitic acid.
~23103~
Suitable polyhydric alcohols are principally ethylene glycol,
diethylene glycol, glycerol, trimethylol propane, ditrimethylol
propane, monopentaerythritole, dipentaexythritol, neopentyl
glycol. In addition substances with hydroxylic groups as
well as carboxylic groups can be used, such as dimethylol
prop ionic acid.
A traditional way to increase the molecular weight is
standoff boiling. Treatment with boric acid also polymerizes
crude tall oil. Boric acid is known from the literature
to give prone rings when reacted with fatty acid.
An improved dispersing agent of the invention is obtained
if the amount of large molecules is increased by distillation
of the polymerized crude tall oil before the partial ester-
ligation.
A residue obtained in distilling fatty acids from fats or
oils of animal or vegetable origin can also be partially
eastward with a polyalkylene glycol or a monster or
monoether thereof to produce a dispersing agent with imp
proved properties.
Pi dispersing agent of the invention is obtained by
reacting polymerized crude tall oil and polyalkylene-
glycol or a monster or monoether thereof. The polyp
alkaline glycol is mainly composed by ethylene oxide units,
as it is essential that it has a hydrophilic character.
As examples of monstrous thereof can be mentioned esters
of carboxylic acids of the type R-COOH, wherein R is a
hydrocarbon residue of 1 - 19 carbon atoms, preferably
1 - 4 carbon atoms, such as acetic acid, prop ionic acid,
butyric acid. Menorahs of polyalkylene glycol are alkyd
ethers, wherein the alkyd group can have 1-20 carbon atoms,
preferably 1-5 carbon atoms. As examples can be mentioned
monoethers of polyethylene glycol of the formula
R-O-(CH2CH2O)n-CH2 SHEA, wherein R is alkyd with 1-5
carbon atoms and n is a number ~12. For economical reasons
polyethylene glycol is, however, preferred.
3 3
For the steno hindrance effect to be pronounced it is
necessary that the polyalkylene glycol has a sufficiently high
molecular weight, 600 at the lowest. Conveniently the molecular
weight is between 4,000 and 10,000, but also higher values can be
applicable
For the preparation of a dispersing agent of the
invention polymerized tall oil and polyalkylene glycol or a
monster or monoether thereof, are reacted in a ratio of 10:90
to 90:10, preferably 30:70 to 70:30, by mixing and heating during
a period of time being sufficient for the acid value to be
reduced with at least 2 units. A larger amount of tall oil will
give a less expensive product and a larger amount of polyelkylene
glycol will give a more efficient product.
If the polyethylene glycol and crude tall oil are used
as reactants the reaction can be proceeded at 200 to 300C for 1-
12 h at atmospheric pressure, preferably 230-280C, depending on
the molecular weight and the residual acid value desired.
The dispersing agent of the invention is used for
dispersing coal particles in water for the preparation of a so-
called coal-water slurry. Many ways to prepare and stabilize
coal-water slurries have been suggested. The reason for this is
that slurries of a high coal content make possible transport and
combustion of coal in liquid form. By this a less risky and more
environmentally adapted handling is achieved compared to the
handling of dry, solid coal or oil. To make the coal-water
slurry fluid at the concentration ranges in question chemicals
have to be added. The dispersing agents previously used make the
preparation of a dispersion of pulverized coal in water which can
be pumped more expensive and thereby the use of the new technique
more difficult. By means of the dispersing agent of the
invention having varying amounts of ionic groups, such a chemical
can be produced at a low price, which is of great importance for
a commercial utilization of coal-water slurries.
'
I 2
When the dispersing agent of the invention is used to
disperse coal particles in water it is convenient to use the
dispersing agent in an amount of 0.01-5~, preferably 0.05-2, and
preferably 0.3-1%, based on the total weight. The particle size
of the coal normally is mainly within the range 1-20 m.
The invention is described in a more detailed way in
the following Examples, in which the stated percentages and
proportions are based on the weight.
The dispersing characteristics of the reaction products
prepared in Examples 1-4 have been determined in the same way as
the oil value for pigment ISIS 17 61 05); the stated value,
however, defines the amount of coal particles which can be
dispersed into a free flowing product. The following procedure
is used; l g bituminous coal having a particle size distribution
that more than 40% is within the range 60-90/~m, is weighed on a
blasted glass plate. Water comprising I dispersing agent is
added. The amount of aqueous phase which has to be added to make
the coal-slurry free flowing in working the pulverized coal with
a spatula is noted. The accuracy is +0.5%.
The flow properties and the stability of the coal-water
mixture (CAM), which are critical for the pump ability and storage
durability thereof, are inter aria dependent on the way in which
the mixture has been prepared. To obtain reproducible CWM-tests
the following procedure has been used in Examples 4-8.
-- 10 --
,
31~)32
The dispersing agent is swelled in water of 80C and then
homogenized in an Ultraturra~x mixer. Alkali is then added
if desired. This liquid is added in portions to the pulverize
coal, which consists of sieved particles which have passed
through a mesh opening of 250 em. The premixed CAM sample
is disintegrated in a dissolver at 2000 ruin for 20 minutes.
The viscosity of these CAM samples was measured in a Brook field
viscosimeter, type LVF, Noah at 30 r/min. BY this the
apparent viscosity is obtained. The storage stability was
measured by means of the following penetration test which
discloses tendencies for aggregation and/or sedimentation in
the CAM sample. A glass rod I g, 1.7 mm) is allowed to
fall to the bottom in a CAM sample of a volume of 100 ml
and a height of 173 mm and the time required is measured.
Example 1
Heating of crude tall oil and partial esterification
with polyethylene glycol.
Crude tall oil having the analysis data below two called
not distillable crude tall oil) is charged into a reactor
provided with a mechanical stirrer and protective atmosphere.
To the reactor was connected a short column to collect
reaction water in the receiver belonging to it.
Analysis data:
Acid value = 134
Rosin content = 14%
Unsaponifiable = 23
Viscosity
(20C Emil) = 505 maps
The temperature ox the crude tall oil was increased to
280C and retained for 2 hours, thereafter the viscosity
was 1 400 maps icky Emil) and the acid value had de-
dined 32- units to 102.
To this heated crude tall oil (105 g) polyethylene glycol
of a molecular weight of 8000 ~245 g) us charged. The
-12 ~3~032
temperature of the mixture was maintained at 280C for
2 hours. A 3% water solution of the reaction mixture
can maximally disperse 68~ coal.
Heating of crude tall oil and partial esterification
with polyethyleneglycol can also be performed in one
step. This will, however, give a somewhat inferior disk
pursing agent, maximum 67% coal in the slurry.
EXAMPLE 2
1 0
Heating of crude tall oil from the sulfite pulping
process and partial esterification with polyethylene-
glycol.
The extractive material of the trees can be recovered
also in producing pulp by the sulfite process This
so called sulfite anthraquinone process is reported
in literature to give a tall oil of good quality. By
ultrafiltration and evaporation a stream rich on extractive
material (dry matter content 40%) can be obtained from the
sulfite pulping process. This emulsion of water and
extractive material from the wood can be broken
by the addition of diluted acid and heating. The lipid
phase which is separated then has an acid value of 63.
By reaction thereof with polyethyleneglycol (molecular
weight 8000) at 280C to an acid value of 8 a substance
is obtained which when added to water (1% of the total
mixture) makes it possible to disperse 69~ coal and
obtain a parboil slurry.
EXAMPLE 3
Heating of crude tall oil in the presence of BF3 and
partial esterification with polyethylene glycol.
Dehydrated crude tall oil (1660 g) having an acid value
of 140, a rosin content of 29% and a viscosity of 115 maps
(50C) are charged into a reactor provided with a mechanical
13 1~31~32
stirrer with protective atmosphere. The temperature
of the crude tell owl is raised to 125C and BF3-solution
(20 g) is added. The mixture is kept at this temperature
for 4 Horace and then the temperature is increased to
250C and the reaction mixture blown with water steam
for 1 hour. 120 ml oil is taken away together with the steam
The reaction product so obtained has an acid value of
120 and a viscosity at 50C of 2 100 maps The boron-
trifluoride solution has a content of 47% in deathly--
ether.
1 0
The reaction can also be interrupted by addition of water
without steam blowing. During these conditions the reaction
mixture will, however, contain BF3 residues. Fatty acids
and rosin acids can also be treated in this way.
The table below shows the properties of different dispersing
agents as to their ability to produce a coal-water slurry
having a high coal content. ill dispersing agents have
been prepared by partial esterification with polyethylene
glycol (molecular weight 4000) at 280C.
Lipid part Maximum coal content in
the coal-water slurry (~)
BF3-treated fatty acid 66
25 BF3- " rosin acid 68
BF3- " crude tall oil 67
Crude tall oil 66.
As a comparison it can be mentioned that distilled water
can disperse about 50% coal in a flowing slurry. The
addition of crude tall oil to the water in an amount of
I (pi = 7) has no positive effect on this. The effect
of the length of the chain of the polyethylene glycol chain
is also of importance for the function of the dispersing
agent. Polymerized rosin acid has a capacity for dispersing
maximum 68% when being reacted with polyethylene glycolof
a molecular weight of 4000 while 70% coal in water can
be dispersed if the polyethylene glycolchain is prolonged
(molecular weight 8000).
14 I 32
Pure rosin acid being esterified with polyethylene
glycol can disperse 69% coal and pure tall oil fatty
acid esterified with polyethyleneglycol (molecular
weight 8000) can disperse 61~ coal in water at the most
Pure fatty acid and polymerized fatty acid being ester-
fled with polyethyleneglycol both give coal-water slurries
of a short consistency, all other dispersing agents give
a slurry of a smoother consistency.
EXAMPLE 4
Treatment of crude tall oil with multi functional alcohol and
acid and partial esterification with polyethylene~qlycol
By adding multi functional alcohol and acid to crude tall oil
a viscosity increase is obtained. Tall oil having the
analysis data according to example 1 (548 g) is charged
I, in a reactor equipped as in example 1 together with
Audrey f Of
- Polyol POX product consisting of polyhydric alcohols
having a functionality between 2 and 4, produced by
Perstorp ABE (91 g) and malefic Andy; The mixture
is kept at 230C until the acid value has declined to
- 34, the viscosity then being 5000 maps (Emil 50C).
To 105 g of the reaction mixture is added 245 g polyp
ethylene glycol (molecular weight 8000~ and the temperature
is raised to 280C. After 2 h the acid value of the mixture
is 9 and a 3% water solution can disperse 70% coal.
An addition of amine to the dispersing agent also increases
the amount of coal in the coal-water slurry. By adding
0.5~ diethylene thiamine to the dispersing agent which has
been prepared above and maintaining the mixture for 1.5,h
at 160C the coal-water slurry can disperse another 1%.
In the same way other multi functional acids and alcohols can
also be reacted with tall oil. Some examples follow below.
1~:3~03~
A common photo in all cases is that a polymerization
has taken place and that the product after reaction at
280C with polyethylene glyc~l molecular weight 8000)
has a residual acid value.
Additive to the Viscosity of Residual acid Mum amount
crude I oil the polymerized value of the of coal in free
crude tall oil polyethylene- flawing coal ~20
(50C),MPa-s glycolester --slurry with
1% dispersing agent
Trimethylol propane 1 200 6 71
Trimellitic acid
Monopentaerythritol 4 700 7 69
Malefic android
15 Trimethylol propane 1 600 7 70
Malefic android
Dipentaerythritol40 000 6 71
Malefic android
The viscosity of a 70% C CAM prepared from 0.5% of the
reaction of tall oil and trimethylol propane and trimellitiC
acid stated above is 270 maps and the time for penetration,
as defined above, is 14 s. after one week of storage.
Standoff boiling is a traditional way to increase the
molecular weight. An ester of tall oil fatty acid and
dipentaerythritol with a residual acid value of 9 - 11
having a viscosity (20C, EIoppler) off - 500 maps after
standoff boiling has a viscosity of 3500 - 6500 maps
(20C). The viscosity of the reaction product of crude
tall oil, trimethylol propane and malefic android
prepared above can in 2 h be increased from 1600 ma s
to 14 500 ma s (50C) by standoff boiling at 272C
under protective atmosphere. By air blowing the sample
the same increase of viscosity can be accomplished but at
a lower temperature, about 250C.
16 ~23~03~
EXAMPLE 5
Heating of crude tall oil in the presence of boric acid
and partial esterification with polyethylene glycol.
Crude tall oil (800 g) having an acid value of 134, a
rosin content of 14% is charged into a reactor provided
with a stirrer and receiver for collecting water. The
crude tall oil is dehydrated by raising the temperature
to 185C and then cooled to 50 C and 24 g boric acid
is added. The mixture was heated to 270C and maintained
at this temperature for 9 h r the viscosity of the oil having
been increased from 80 maps (50C) to 2250 maps During
the heating of the crude oil tall a substantial molecular
enlargement has taken place.
90 g of the product obtained and 210 g polyethylene glycol
(molecular weight 8000) are charged into a reactor and
heated. After 1 h at 280C the acid value of the mixture
has decreased 3 units. Addition of 0.5% of this product
to a 70% C CAM gives a slurry having a viscosity of 340 maps
and not forming a hard sediment after storing for 18 days.
EXAMPLE 6
Polymerizing crude tall oil in the presence of a cobalt
catalyst and distillation of the product obtained followed
by partial esterification with polyethylene glycol.
Dry crude tall oil (800 g) having an acid value of 141
and a rosin content of 30% as well as 0.1% cobalt catalyst
(Co napthenate) are charged into a reactor and the mixture
is kept at 270C for approximately 8 h. The viscosity then
is 5500 maps at 20C. From this product 30% of the most
volatile components are removed by distillation. After
reaction with polyethylene glycol (molecular weight 8000)
in the ratio 3:7 at 240C an additive for dispersing coal
in water is obtained.
17 ~3~)3;~
Reaction time Acid value Viscosity of Penetration time
h 70%C CAM after Ed
0.5% additive s
maps
0.75 32 3415 ~60
1.0 29 240 10
2.0 28 215 12 -
An additive prepared as above but from crude tall oil not
being polymerized or distilled, gives a CAM which after 7 days
has formed a sediment.
EXAMPLE 7
A dispersing agent was prepared from pitch obtained during
distillation of fatty acids, mainly C-18 unsaturated. These
fatty acids originate from a mixture of edible oils.
30% pitch (acid value = 27) was reacted with 70% polyethylene
glycol (MY = 8000) at 280C for -I h. From this product a 70% C
CAM containing 0.5% additive was prepared. This CAM has an
apparent viscosity of 390 maps and the time for penetration
amounts to 8 seconds after 9 days.
EXAMPLE 8
Dimerizing ox fatty acids improves the dispersing properties
in the corresponding polyethylene glycol ester, compared to
the monomer acid. Tall oil fatty acid (acid value 192) and
dimerized fatty acid (acid value 193) respectively were
reacted with polyethylene glycol (molecular weight 8000)
by heating at 220 - 250C in a ratio of 3:7. The reaction
was followed by reduction in acid number and the ability
of the reaction minutes (0.5& w/w) to disperse 70% w/w coal
in water as well as the stability of the slurry against
sedimentation was examined. This example also shows that
a polyethylene glycol with a diver fatty acid in both
chain ends has very good dispersing properties for coal in
water.
18
~23~)3~:
Tall oil fatty acid and polyethylene glycol (My 8000)
Acid value Viscosity of slurry Penetration time
reduction maps s
of reaction ' -
mixture
2.6 970 >60
4.4 130 >60
6.6 250 >60
9.4 540 >60
1 1 *
*Impossible to disperse in water.
Dimerized fatty acid and polyethylene glycol (My 8000)
Acid value
seduction Viscosity of slurry Penetration time
of reaction maps s
mixture
2.7 200 >60
5.5 200 28
7.5 210 16
9.3 220 6
11 250 5
13 280 3
