Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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'.,. 1
Production of tall oil
The present invention relates to a procedure for producing
tall oil from tall oil soft soap produced as a by-product
in the cellulose industry, and by separating the tall oil
thus produced from the mother water and lignin.
As a by-product of the cellulose industry valuable tall
oil soft soap is produced, gathering in pulp production on
the surface of the solution while concentrating the mother
solution, i.e. in conjunction with water vaporization. The
soft soap is shaved off from the surface of the vessel and
acidified, whereby tall oil is produced. The tall oil is
distilled further, whereby valuable rosin acids and fatty
acids are obtained as distillation fractions.
The reaction is chemically simple, and the rosin and fatty
acids present therein in the form cf sodium salts are made
to react with sulphuric acid, whereby respective carboxylic
acids and sodium sulphate are produced.
For the acidification of tall oil soft soap, sulphuric
acid has been used, this being well suited for said pur-
pose since it makes possible the addition of neutralized
sulphuric acid in the chemical cycle of the pulp mill. The
sodium sulphate thus produced is a useful addition in sub-
stituting the sulphur losses in the pulping process. How-
ever, owing to the limitations concerning the protection
of the environment, the pulp mills have reduced their sul-
phur releases to the extent that the sulphuric acid used
in the acidification process of tall oil soft soap no
longer can be used to substitute the considerably reduced
sulphur losses of the pulp mill. Therefore, endeavours
have been made to develop acidification alternatives in
producing tall oil.
1~ $
2056~fi
.
In conjunction with the present invention it was surpris-
ingly found that for acidifying tall oil soft soap, mono-
valent hydrochloric acid can be used instead of bivalent
sulphuric acid. The amount of hydrochloric acid needed for
an equal amount of tall oil soft soap is equal to that of
the bivalent sulphuric acid. The hydrochloric acid is low
in price, it is readily available, and the sewage produced
in acidifying the hydrochloric acid is ecologically more
beneficial than the sewage produced in acidifying sul-
phuric acid.
As regards the corrosion properties, sulphuric acid and
hydrochloric acid are very similar. In certain conditions
and in certain concentrations, however, the sulpuric acid
is more corroding than the hydrochloric acid, because of
which the use of sulphuric acid is recommended, too.
The essential characteristics of the invention are pre-
sented in the accompanying claims.
For hydrochloric acid, dilute, concentrated or gaseous
hydrochloric acid can be used on the condition that its
amount is sufficient for neutralizing the fatty and rosin
acids present in the tall oil soft soap. Excess use causes
extra costs.
The acidification of tall oil soft soap is carried out in
the temperature range 60 to 220~C, preferably in the range
85 to 100~C. At temperatures over 100~C, a pressure reac-
tion is to be considered. The reaction time is not very
significant but the best time was found to be 10 to 30
minutes. No advantage was gained from a longer time.
The changes in the quality of the tall oil soft soap are
dependent on the quality of timber used in manufacturing
pulp. When pulping only pine, good quality tall oil soft
2Q56836
soap is produced, the acid number of the tall oil obtained
therefrom being 140 to 160 mg KOH/g and the rosin acid
content being 30 to 50%. However, in pulping birch the
quality of the soft soap changes so that the acid number
of the respective tall oil is 100 to 120 mg KOH/g, being
even lower, the rosin acid content being then 20 to 30%.
Irrespective of the quality, hydrochloric acid can appro-
priately be used in acidification process of tall oils in-
stead of the sulphuric acid.
After the acidification process, the tall oil layer can be
separated from the mother water and the lignin layers eit-
her by allowing the layers to be separated or by centri-
fugalizing them off with a centrifuge.
The invention is illustrated with the following examples.
Example 1
42 ml of 37% hydrochloric acid were used and 42 ml water
were added. The mixture was heated to 80~C. In the mixture
190 g of 50% tall oil soft soap were added gradually. It
was mixed for 10 minutes at 80~C and 15 minutes at 90~C,
whereafter the mixture was poured into a graduated glass.
The layers were allowed to be separated at 80~C for 30
minutes, whereafter the tall oil could be decanted off.
The analyses of the tall oil thus obtained were as fol-
lows.
yield * ~ 57.5
acid number mg KOH/g 150
rosin acids % 34
unsaponifiable % 12
fatty acids % 54
* Calculated: separated tall oil/tall oil soft soap * 100%
~ 4 2056836
Example 2
50 ml water were used and 50 ml of 40% sulphuric acid were
added. The mixture was heated to 90~C and 200 g of 45~C
tall oil soft soap were added. It was mixed for 10 minutes
at 80~C and 15 minutes at 90~C, whereafter the mixture was
poured into a graduated glass. The layers were allowed to
be separated at 80~C for 30 minutes, whereafter the tall
oil could be decanted off. The analyses of the tall oil
thus obtained were as follows.
yield * % 55
acid number mg KOH/g 150
rosin acids % 35
unsaponifiable % 12
fatty acids % - 53
* Calculated: separated tall oil/tall oil soft soap * 100%
Using the Examples 1 and 2, a gas chromatography analysis
was carried out; for the tower, a 25 meter quartz capil-
lary tower as the butane diol succinate liquid phase (BDS)
was used. The run was carried out isothermically at 197~C.
The main components were as follows.
Example 1 Example 2
9-C18:1 14.6% 14.4%
(oleic acid)
9.12-C18:2 20.5% 19.9
(linoleic acid)
abietic acid 13.1% 11.7%
dehydroabietic acid 7% 7%
It can be seen in the above results that in using hydro-
chloric acid, both the quality and yield of the tall oil
20~68~6
are entirely comparable with the tall oil produced using
sulphuric acid.
Example 3
34 ml of 37% hydrochloric acid were used and 34 ml water
were added thereto. The mixture was heated to 90~C. Into
the mixture 280 g of tall oil soft soap at 50~C were added
gradually. It was mixed for 30 minutes at 90~C, whereafter
the mixture was poured into a graduated glass. The layers
were allowed to be separated at 90~C for 60 minutes,
whereafter the tall oil could be decanted off. The anal-
yses of the tall oil thus obtained were as follows.
yield * % 21
acid number mg KOH~g-108
water % 4.5
rosin acids % 34
unsaponifiable 12
* Calculated: separated tall oil/tall oil soft soap *
100%
Example 4
34 ml of 37% hydrochloric acid were used and 34 ml water
were added. The mixture was heated to 90~C, and 150 g of
tall oil soft soap at 50~C were added. It was mixed for 30
minutes at 90~C, whereafter the mixture was poured into a
graduated glass. The layers were allowed to be separated
at 90~C for 60 minutes, whereafter the tall oil could be
decanted off. The analyses of the tall oil thus obtained
were as follows.
205~ 6
yield * % 37%
acid number mg KOH/g 149
water % 1.5
rosin acids %32.7
fatty acids %51.4
unsaponifiable %15.9
* Calculated: separated tall oil/tall oil soft soap *
100%
From the Examples 3 and 4 a gas chromatography analysis
was made; for the tower a 25 meter quartz capillary tower
was used as the butane diol succinate liquid phase (BDS).
The run was carried out isothermically at 197~C. The main
components were as follows.
Example 3 Example 4
9-C18:1 14.3% 17.7%
(oleic acid)
9.12-C18:2 19.3~ 24.7%
(linoleic acid)
abietic acid11.6% 16.0%
dehydroabietic acid 7.8% 5.9%
It is seen from the above results that a change in the
soap/hydrochloric acid ratio makes no great effect on the
quality of tall oil being separated, but only on the layer
separation rate.
Example 5
34 ml of 37% hydrochloric acid were used and 34 ml water
were added thereto. The acid mixture was heated to 60~C
and 190 g of 50~C tall oil soft soap were added to the
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mixture. It was mixed for 30 minutes at 60~C, whereafter
the mixture was poured into a graduated glass. The layers
were allowed to be separated for 75 minutes, whereafter
the tall oil could be decanted off. The analyses of the
tall oil thus obtained were as follows.
yield * % 26
acid number mg KOH/g 151
rosin acids % 35
unsaponifiable % 13
fatty acids ~ 52
* Calculated: separated tall oil/tall oil soft soap *
100 %
One may see from the results that at a low temperature
like above the yield become~ laller and the separation of
the layers more difficult.
Example 6
63 g of tall oil soft soap, 11.3 ml of concentrated 37%
hydrochloric acid and 11.3 ml water were used. The ingred-
ients were inserted in an autoclave and the temperature
was raised to 170~C. It was allowed to be mixed for 30
minutes at 170~C, whereafter the mixture was allowed to
cool down and the separated tall oil was decanted off. The
analyses of the tall oil thus obtained were as follows.
yield * % 50
acid number mg KOH/g 134
rosin acids % 32.9
unsaponifiable % 14.7
fatty acids % 52.4
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* Calculated: separated tall oil/tall oil soft soap *
100 ~
From the tall oil obtained in the manner described in
Examples 5 and 6 a gas chromatography analysis was carried
out (BDS tower, 197~C, isothermic run). The main com-
ponents of the tall oil were as follows.
Example 5 Example 6
9-C18:1 14.7% 13.9%
9.12-C18:2 20.4% 18.2%
abietic acid 19.7% 18.8%
dehydroabietic acid6.8% 10.2%
ExamPle 7
34 ml of concentrated 37% hydrochloric acid were used and
34 ml water were added thereto. The mixture was heated to
97~C and 190 g of 50~C tall oil soft soap were added. It
was mixed for 30 minutes at 97~C, whereafter the mixture
was poured into a graduated glass, and after a while, the
separated lignin and tall oil layer were decanted off from
the mother water. The mixture was poured into a centrifuge
tube and was centrifugalized 5300 x g for 20 minutes. The
analyses of the tall oil thus obtained were as follows.
yield * % 47
acid number mg KOH/g 152.5
unsaponifiable % 13.2
* Calculated: separated tall oil/tall oil soft soap *
100%
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On the basis of a gas chromatography analysis (BDS tower,
197~C, isothermic run), the main components of the tall
oil were as follows.
9-C18:1 15.3%
(oleic acid)
9.12-C18:2 14%
(linoleic acid)
abietic acid 25%
dehydroabietic acid 7.8%
On the basis of analyses, the tall oil separated by cen-
trifugalizing is of good quality.
Example 8
63 g soap, 11.3 ml concentra'~-d 37% hydrochloric acid and
11.3 ml water were used. The ingredients were inserted
into an autoclave and the temperature was raised to 220~C,
the pressure being 14 bar. It was allowed to be mixed for
30 minutes at 220~C, whereafter the mixture was allowed to
cool and the separated tall oil was decanted off. The
analyses of the tall oil thus obtained were as follows.
yield* % 49
acid number mg KOH/g 124
rosin acids % 29
unsaponifiable % 19
-- fatty acids % 48
* Calculated: separated tall oil/tall oil soft soap *
100%
The low acid number of the separated tall oil is obviously
due to esterification or decarboxylation.
2056~6
From the tall oil obtained as in Example 8 a gas chromato-
graphy analysis was performed (BDS tower, 197~C, isother-
mic run). The main components of the tall oil were as fol-
lows.
9-C18:1 15.5%
(oleic acid)
9.12-C18:2 15.5%
(linoleic acid)
abietic acid 11.3%
dehydroabietic acid 15.9%
On the basis of the gas chromatography analysis it seems
to be that differences compared with the earlier ones com-
mence beiny found in acid distributions at said high tem-
perature; isomeration of linoleic and abietic acids taking
place.
