Chemistry Reference
In-Depth Information
The acetylene was later replaced by butadiene for economic reasons. Butadiene is cyclodimerized, then
hydrogenated to cyclooctane, and the oxime is prepared directly from cyclooctane by photonitrosation:
NOH
HCl
NOCl
Beckmann
rearrangement
7
O
etc.
h
ν
N
H
-pelargonamide) is produced in Russia together with nylon 7, poly
(aminoenanthic acid) as described above. In the U.S., Kohlhase et al. [
67
] developed a route to
nylon 9 via ozonolysis of unsaturated fatty acids like those that can be obtained from soybean oil. The
glycerol fatty acid esters of oleic, linoleic, and linolenic acids are transesterified with methanol to
form methyl esters. The esters are then cleaved via ozonolysis to yield methylazelaldehyde and by-
products that are removed. The purified product is reacted with ammonia and then reduced over
Raney nickel to yield a methyl ester of the amino acid:
Nylon 9
or poly(
o
H
2
N
OCH
3
O
After hydrolysis and purification, the free amino acid is converted to high molecular weight
polymers [
68
]. To date, nylon 9 has not been commercialized in the U.S., though the polymer has a
high melting point of 209
C and is more flexible than nylon 6. It is also lower in water absorption.
Nylon 11
was originally synthesized in France. The monomer,
o
-amino-undecanoic acid, is
obtained from methyl ricinoleate that comes from castor oil. Methyl ricinoleate is first cleaved
thermally to heptaldehyde and methyl undecylenate:
O
OH
Δ
OCH
3
+
C
6
H
13
H
OCH
3
7
5
8
O
O
The ester is then hydrolyzed and converted to an amino acid:
O
O
H
2
O
HBr
peroxide
OCH
3
OH
8
8
O
O
counter
Markovnikov
addition
NH
3
Br
H
3
N
OH
O
10
10
Polycondensation is conducted in the melt under nitrogen at 215
C for several hours. The polymer
is transparent in its natural form. It has high-impact resistance, low moisture absorption, and good low
temperature flexibility. It is also manufactured in the U.S.
Nylon 12
is produced in U.S., Japan, and Europe with the original development coming from
Europe. All current manufacturing processes of this polyamide, formed by ring opening polymeriza-
tion of lauryl lactam, are based on cyclododecatriene. This ring compound can be obtained by
