Answers to the Quickies
361
Answers to 7 Chap. 5
1. All three oils mentioned contain predominantly fatty acids with a C18 chain length
(. Table 2.1). The weight proportion of
glycerine in these oils is approx. 10–11%.
2. Glycerol is only well miscible with very
polar solvents, i.e. with water and ethanol.
Glycerol is very slightly soluble in ether and
insoluble in hydrocarbons.
3. Glycerol can be distilled in packed distillation columns as well as in thin film evaporators under vacuum.
4. Kosher glycerol must not originate from
animal fats. Either natural glycerol is taken
from vegetable oils or a synthetic glycerol
from propene.
5. By reacting glycerol with “nitrating acid”, a
mixture of nitric acid and sulfuric acid. The
nitrating acid also gave the wrong name to
glycerine trinitrate, “nitroglycerol”.
6. In the synthesis of triacetine, glycerol is
reacted with acetic acid in a first stage and
with acetic anhydride in a second stage. This
is the only way to achieve an almost complete conversion of the glycerol.
7. Glycerol carbonate is currently produced by
transesterification of glycerol with ethylene
carbonate or dimethyl carbonate. A direct
synthesis from glycerol and carbon dioxide
is very difficult and not yet economical.
When glycerol carbonate is split by zeolite
catalysis, glycidol is formed under elimination of carbon dioxide.
8. During the synthesis of GTBE, a mixture
of monoethers and higher ethers is always
formed. However, the product mixture is
extracted after synthesis with fresh glycerol: The polar monoethers dissolve in the
glycerol and are returned to the reactor for
further etherification, where they are converted to higher ethers with fresh isobutene.
Only, the higher ethers leave the plant.
9. In the same reactor, you carry out both
hydroformylation and acetalization. You
therefore apply the following substances:
Glycerol, alkene, p-toluenesulfonic acid,
rhodium complex, solvent (toluene), synthesis gas. Rhodium catalyzed in the solvent
toluene, alkene and synthesis gas form the
aldehyde, which then reacts acid catalyzed
with glycerol to form the acetal.
10. 1,3-Propanediol is a possible diol for esterification with terephthalic acid. Polyester
is formed, which are processed into fibers
(trade names: Sorona, Corterra).
Answers to 7 Chap. 6
1. Important monosaccharides are glucose,
which is industrially obtained by starch
hydrolysis, fructose, which occurs in many
fruits and is industrially accessible by cleavage of sucrose and inulin, mannose, which
occurs in nuts and seeds, and galactose,
which is bound in lactose.
2. Lactic acid is the starting material for polylactic acid, lactates, 1,2-propanediol, acrylic
acid and pyruvic acid.
3. 5-hydroxymethylfurfural is formed during
the dehydration of hexoses and furfural is
formed during the dehydration of
pentoses.
4. Hydrogenation of 5-hydroxymethylfurfural
produces 2,5-bis(hydroxymethyl)furan,
oxidation results in 2,5-furandicarboxylic
acid. Both are monomers for the synthesis of
polyesters.
5. Sugar alcohols are oligo-alcohols, which
are accessible by hydrogenation of sugars.
Examples are sorbitol (from glucose), mannitol (from fructose), xylitol (from xylose)
and isomalt (from isomaltulose). They are
used as sweeteners (sugar substitutes). Sorbitol is also a starting material for l-ascorbic
acid, vitamin C.
6. The reaction between glucose and fatty
alcohol is carried out by acid catalysis in a
stirred tank with a loop containing an intensive mixer. This reaction technique ensures
that the two starting components, which are
insoluble in each other, come into sufficient
contact. With a high excess of fatty alcohol
and the removal of the water in a vacuum,
glucose is converted to alkyl polyglucosides
with an almost 100% conversion. After neutralization, the excess fatty alcohol is carefully removed in a vacuum and the product
is bleached with H 2 O 2 and packaged. APG
361
Answers to 7 Chap. 5
1. All three oils mentioned contain predominantly fatty acids with a C18 chain length
(. Table 2.1). The weight proportion of
glycerine in these oils is approx. 10–11%.
2. Glycerol is only well miscible with very
polar solvents, i.e. with water and ethanol.
Glycerol is very slightly soluble in ether and
insoluble in hydrocarbons.
3. Glycerol can be distilled in packed distillation columns as well as in thin film evaporators under vacuum.
4. Kosher glycerol must not originate from
animal fats. Either natural glycerol is taken
from vegetable oils or a synthetic glycerol
from propene.
5. By reacting glycerol with “nitrating acid”, a
mixture of nitric acid and sulfuric acid. The
nitrating acid also gave the wrong name to
glycerine trinitrate, “nitroglycerol”.
6. In the synthesis of triacetine, glycerol is
reacted with acetic acid in a first stage and
with acetic anhydride in a second stage. This
is the only way to achieve an almost complete conversion of the glycerol.
7. Glycerol carbonate is currently produced by
transesterification of glycerol with ethylene
carbonate or dimethyl carbonate. A direct
synthesis from glycerol and carbon dioxide
is very difficult and not yet economical.
When glycerol carbonate is split by zeolite
catalysis, glycidol is formed under elimination of carbon dioxide.
8. During the synthesis of GTBE, a mixture
of monoethers and higher ethers is always
formed. However, the product mixture is
extracted after synthesis with fresh glycerol: The polar monoethers dissolve in the
glycerol and are returned to the reactor for
further etherification, where they are converted to higher ethers with fresh isobutene.
Only, the higher ethers leave the plant.
9. In the same reactor, you carry out both
hydroformylation and acetalization. You
therefore apply the following substances:
Glycerol, alkene, p-toluenesulfonic acid,
rhodium complex, solvent (toluene), synthesis gas. Rhodium catalyzed in the solvent
toluene, alkene and synthesis gas form the
aldehyde, which then reacts acid catalyzed
with glycerol to form the acetal.
10. 1,3-Propanediol is a possible diol for esterification with terephthalic acid. Polyester
is formed, which are processed into fibers
(trade names: Sorona, Corterra).
Answers to 7 Chap. 6
1. Important monosaccharides are glucose,
which is industrially obtained by starch
hydrolysis, fructose, which occurs in many
fruits and is industrially accessible by cleavage of sucrose and inulin, mannose, which
occurs in nuts and seeds, and galactose,
which is bound in lactose.
2. Lactic acid is the starting material for polylactic acid, lactates, 1,2-propanediol, acrylic
acid and pyruvic acid.
3. 5-hydroxymethylfurfural is formed during
the dehydration of hexoses and furfural is
formed during the dehydration of
pentoses.
4. Hydrogenation of 5-hydroxymethylfurfural
produces 2,5-bis(hydroxymethyl)furan,
oxidation results in 2,5-furandicarboxylic
acid. Both are monomers for the synthesis of
polyesters.
5. Sugar alcohols are oligo-alcohols, which
are accessible by hydrogenation of sugars.
Examples are sorbitol (from glucose), mannitol (from fructose), xylitol (from xylose)
and isomalt (from isomaltulose). They are
used as sweeteners (sugar substitutes). Sorbitol is also a starting material for l-ascorbic
acid, vitamin C.
6. The reaction between glucose and fatty
alcohol is carried out by acid catalysis in a
stirred tank with a loop containing an intensive mixer. This reaction technique ensures
that the two starting components, which are
insoluble in each other, come into sufficient
contact. With a high excess of fatty alcohol
and the removal of the water in a vacuum,
glucose is converted to alkyl polyglucosides
with an almost 100% conversion. After neutralization, the excess fatty alcohol is carefully removed in a vacuum and the product
is bleached with H 2 O 2 and packaged. APG