129
6
surfactants. With the exception of methylamine,
which is still produced petrochemically, they are
made entirely from renewable raw materials.
6.3 Disaccharides
Important disaccharides are sucrose, isomaltulose, lactose, maltose, cellobiose and trehalose
(. Fig. 6.17).
5 Sucrose is by far the most abundant disaccharide. It consists of a fructose and a
glucose unit, linked via an acetal. According
to the IUPAC nomenclature, sucrose is a
β-d-fructofuranosyl-α-d-glucopyranoside.
5 Isomaltulose is a natural component of honey
and sugar cane. It is produced on an industrial scale by the enzymatic isomerization of
sucrose (7 Sect. 6.3.2, . Fig. 6.25). The official
name is 6-O-α-d-glucopyranosyl-d-fructose.
5 Lactose (“milk sugar”) consists of a
galactose and a glucose unit and is a
fied. A general problem, however, is that complex
mixtures are always formed because the degree
of esterification cannot be controlled. Sorbitan
fatty esters act as emulsifiers, which are approved
as food additives and are used in bakery products, sweets and chocolate.
Amination Reactions
During the amination of glucose with methylamine in the presence of hydrogen and nickel
catalysts, N-methylglucamine is formed by elimination of water (. Fig. 6.16). Amination takes
place selectively at C-atom 1 of the glucose. The
secondary amine formed also contains an N–H
group, which can react with a fatty acid methyl
ester in a second reaction step. This base-catalyzed
acylation produces a fatty acid N-methylglucamide. It contains a hydrophilic glucamide part
and a hydrophobic fatty alkyl part and can therefore be used again as a washing-active compound.
Like APG, fatty acid glucamides are well biodegradable, almost non-toxic and very skin-friendly
O
HO
HO
OH
OH
OH
CH 3 NH 2
Methylamine
Glucose
H 2 / [Ni]
- H 2 O
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N H
CH 3
N-Methylglucamine
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N H
CH 3
N-Methylglucamine
H 3 C O C R
O
Fatty acid methyl ester
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N
C
CH 3
Fatty acid
N-methylglucamide
R
O
Acylation
- MeOH
[OH - ]
hydrophobic rest
+
+
1.
2.
. Fig. 6.16 Two-stage synthesis of fatty acid N-methylglucamide from glucose
6.2 · Monosaccharides
6
surfactants. With the exception of methylamine,
which is still produced petrochemically, they are
made entirely from renewable raw materials.
6.3 Disaccharides
Important disaccharides are sucrose, isomaltulose, lactose, maltose, cellobiose and trehalose
(. Fig. 6.17).
5 Sucrose is by far the most abundant disaccharide. It consists of a fructose and a
glucose unit, linked via an acetal. According
to the IUPAC nomenclature, sucrose is a
β-d-fructofuranosyl-α-d-glucopyranoside.
5 Isomaltulose is a natural component of honey
and sugar cane. It is produced on an industrial scale by the enzymatic isomerization of
sucrose (7 Sect. 6.3.2, . Fig. 6.25). The official
name is 6-O-α-d-glucopyranosyl-d-fructose.
5 Lactose (“milk sugar”) consists of a
galactose and a glucose unit and is a
fied. A general problem, however, is that complex
mixtures are always formed because the degree
of esterification cannot be controlled. Sorbitan
fatty esters act as emulsifiers, which are approved
as food additives and are used in bakery products, sweets and chocolate.
Amination Reactions
During the amination of glucose with methylamine in the presence of hydrogen and nickel
catalysts, N-methylglucamine is formed by elimination of water (. Fig. 6.16). Amination takes
place selectively at C-atom 1 of the glucose. The
secondary amine formed also contains an N–H
group, which can react with a fatty acid methyl
ester in a second reaction step. This base-catalyzed
acylation produces a fatty acid N-methylglucamide. It contains a hydrophilic glucamide part
and a hydrophobic fatty alkyl part and can therefore be used again as a washing-active compound.
Like APG, fatty acid glucamides are well biodegradable, almost non-toxic and very skin-friendly
O
HO
HO
OH
OH
OH
CH 3 NH 2
Methylamine
Glucose
H 2 / [Ni]
- H 2 O
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N H
CH 3
N-Methylglucamine
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N H
CH 3
N-Methylglucamine
H 3 C O C R
O
Fatty acid methyl ester
H 2 C
C OH
H
C H
HO
C OH
H
C OH
H
CH 2 OH
N
C
CH 3
Fatty acid
N-methylglucamide
R
O
Acylation
- MeOH
[OH - ]
hydrophobic rest
+
+
1.
2.
. Fig. 6.16 Two-stage synthesis of fatty acid N-methylglucamide from glucose
6.2 · Monosaccharides