Answers to the Quickies
359
a solid surface: It seems to “dry up”. Two
other oils, old sunflower oil and safflower
oil, contain larger proportions of the twofold
unsaturated linoleic acid. They behave in the
air similar to linseed oil and are sometimes
referred to as “semi-drying” oils.
9. The highest concentrations of oleic acid are
found in high-oleic sunflower oil (91%) and
in olive oil (84%). Important sources are also
the new rapeseed oil (60%) and relatively
inexpensive lard and tallow (40–50%).
10. When the extract phase decompresses, the
gaseous carbon dioxide evaporates completely, and the remaining oil is guaranteed
free of organic solvents such as n-hexane, etc.
Answers to 7 Chap. 3
1. Fatty acids, fatty esters, fatty alcohols,
glycerol.
2. Fat hydrolysis generates glycerol water,
which contains only very diluted
glycerol due to the large excess of water
during the reaction. The processing is thus
time-consuming (7 Chap. 5). Fat transesterification produces much more concentrated
glycerol.
3. Stearic acid boils very high, namely at
370 °C, because carboxylic acids form
dimers with each other via hydrogen bonds.
Stearic acid must therefore be distilled in a
vacuum, e.g. at 10 mbar vacuum and 232 °C
boiling temperature. Stearyl alcohol boils
much lower (. Table 3.1) and can therefore
be distilled at normal pressure or only a
slight vacuum.
4. Industrial soap production requires on
the one hand fats, and bases such as soda
(sodium carbonate) or sodium hydroxide
on the other. In 1861, Solvay developed the
industrial process named after him for the
production of soda from table salt. Sodium
hydroxide could be obtained from the soda
using slaked lime.
5. Both products are formed by hydrogenating
under simultaneous water separation
from the glycerol: If a primary hydroxyl
group of the glycerol is split off as a water
molecule, 1,2-propanediol is formed. If
the second primary OH group is split off,
isopropanol remains. The secondary OH
group of the glycerol molecule is difficult
to cleave; therefore, a selective formation of
1,3-propanediol is not possible.
6. A distinction is made in fatty ester hydrogenation between sump phase hydrogenation (with finely suspended catalyst
particles = slurry) and fixed bed hydrogenation (with lumpy catalyst firmly arranged in
the reactor).
7. By hydroformylation of 1-alkenes with
synthesis gas, linear aldehydes can be
synthesized which are hydrogenated with
hydrogen to long-chain alcohols. The chain
length of these alcohols depends on the alkene used. If an even-numbered alkene from
the SHOP, e.g. 1-dodecene, is used in the
hydroformylation, 1-tridecanol is formed,
i.e. an odd-numbered alcohol, which does
not occur in nature. On the other hand,
even-numbered alcohols are formed from
odd-numbered alkenes, i.e. lauryl alcohol is
formed from 1-undecene.
8. If “partially poisoned” catalysts are used in
the pressure hydrogenation of methyl oleate,
e.g. chromium oxide catalysts doped with
cadmium oxide, the ester group is hydrogenated to the alcohol function, while the
C=C double bond remains.
9. Fat → Fat ester → Fat alcohol → Fat alcohol
ethoxylate → Fat alcohol ether sulfate.
10. Production from stearic acid: Stearic acid is
dehydrated in the presence of ammonia into
the corresponding stearic acid nitrile, which
initially reacts under hydrogen pressure via
the imine intermediate stage to the primary stearylamine and then further to the
secondary distearylamine (. Fig. 3.22). This
is methylated twice with methyl chloride to
the final product. Production from stearyl
alcohol: Two molecules of stearyl alcohol
react with monomethylamine to release
two molecules of water to form the tertiary
amine, distearyl monomethylamine. This
is methylated with methyl chloride to the
desired ammonium salt.
Answers to 7 Chap. 4
1. For the synthesis of AES, the triglyceride
is transesterified with methanol to form a
methyl ester, which is then sulfonated to
359
a solid surface: It seems to “dry up”. Two
other oils, old sunflower oil and safflower
oil, contain larger proportions of the twofold
unsaturated linoleic acid. They behave in the
air similar to linseed oil and are sometimes
referred to as “semi-drying” oils.
9. The highest concentrations of oleic acid are
found in high-oleic sunflower oil (91%) and
in olive oil (84%). Important sources are also
the new rapeseed oil (60%) and relatively
inexpensive lard and tallow (40–50%).
10. When the extract phase decompresses, the
gaseous carbon dioxide evaporates completely, and the remaining oil is guaranteed
free of organic solvents such as n-hexane, etc.
Answers to 7 Chap. 3
1. Fatty acids, fatty esters, fatty alcohols,
glycerol.
2. Fat hydrolysis generates glycerol water,
which contains only very diluted
glycerol due to the large excess of water
during the reaction. The processing is thus
time-consuming (7 Chap. 5). Fat transesterification produces much more concentrated
glycerol.
3. Stearic acid boils very high, namely at
370 °C, because carboxylic acids form
dimers with each other via hydrogen bonds.
Stearic acid must therefore be distilled in a
vacuum, e.g. at 10 mbar vacuum and 232 °C
boiling temperature. Stearyl alcohol boils
much lower (. Table 3.1) and can therefore
be distilled at normal pressure or only a
slight vacuum.
4. Industrial soap production requires on
the one hand fats, and bases such as soda
(sodium carbonate) or sodium hydroxide
on the other. In 1861, Solvay developed the
industrial process named after him for the
production of soda from table salt. Sodium
hydroxide could be obtained from the soda
using slaked lime.
5. Both products are formed by hydrogenating
under simultaneous water separation
from the glycerol: If a primary hydroxyl
group of the glycerol is split off as a water
molecule, 1,2-propanediol is formed. If
the second primary OH group is split off,
isopropanol remains. The secondary OH
group of the glycerol molecule is difficult
to cleave; therefore, a selective formation of
1,3-propanediol is not possible.
6. A distinction is made in fatty ester hydrogenation between sump phase hydrogenation (with finely suspended catalyst
particles = slurry) and fixed bed hydrogenation (with lumpy catalyst firmly arranged in
the reactor).
7. By hydroformylation of 1-alkenes with
synthesis gas, linear aldehydes can be
synthesized which are hydrogenated with
hydrogen to long-chain alcohols. The chain
length of these alcohols depends on the alkene used. If an even-numbered alkene from
the SHOP, e.g. 1-dodecene, is used in the
hydroformylation, 1-tridecanol is formed,
i.e. an odd-numbered alcohol, which does
not occur in nature. On the other hand,
even-numbered alcohols are formed from
odd-numbered alkenes, i.e. lauryl alcohol is
formed from 1-undecene.
8. If “partially poisoned” catalysts are used in
the pressure hydrogenation of methyl oleate,
e.g. chromium oxide catalysts doped with
cadmium oxide, the ester group is hydrogenated to the alcohol function, while the
C=C double bond remains.
9. Fat → Fat ester → Fat alcohol → Fat alcohol
ethoxylate → Fat alcohol ether sulfate.
10. Production from stearic acid: Stearic acid is
dehydrated in the presence of ammonia into
the corresponding stearic acid nitrile, which
initially reacts under hydrogen pressure via
the imine intermediate stage to the primary stearylamine and then further to the
secondary distearylamine (. Fig. 3.22). This
is methylated twice with methyl chloride to
the final product. Production from stearyl
alcohol: Two molecules of stearyl alcohol
react with monomethylamine to release
two molecules of water to form the tertiary
amine, distearyl monomethylamine. This
is methylated with methyl chloride to the
desired ammonium salt.
Answers to 7 Chap. 4
1. For the synthesis of AES, the triglyceride
is transesterified with methanol to form a
methyl ester, which is then sulfonated to