Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a process for hydrox-
ylating olefinically unsaturated compounds containing 4 to 36
carbon atoms and having boiling points above 40C by reaction
with formic acid and hydrogen peroxide at elevated temperature
while intimately mixing and by subsequent saponification of the
formates obtained.
The production of 1,2-diols by reaction of l-olefins
containing 8 to 18 carbon atoms with formic acid and hydrogen
peroxide at a temperature of 40C while intimately mixing and
by subsequent saponification of the formates formed is known
(D. Swern et al. in J. Am. Chem. Soc. 68r (1946), page 1504 to
1507). In this process the formic acid is used in amounts of
approximately 9 -to approximately 31 moles per mole of olefin
used depending on the olefin used~ Hyarogen peroxide is used
in a concentration of 25.6 percent by weight. Depending on
the olefin used the reaction requires a reaction time from
approximately 8 to approximately 24 hours. In fact the crude
1,2-diols are obtained in the saponification of the diol mono-
formates formed in yielas of up to and exceediny 70~, but the
yield of pure 1,2-diol is only between 40 and 70% depending
on the olefin used.
The process according to the invention is characterized
in that the formic acid is used in amounts of 2 to 6 moles
per mole of double bond, that hydrogen peroxide is used in a
concentration of 35 to 98 percent by weight and that the
reaction is carried out at a temperature between 40 and 80C.
Under these conditions a reaction time of less than 7 hours, for
example, 1 to 3 hours, is sufficient to attain a high reaction
rate. Depending on the olefin used, the yield of pure olefin is
between approximately 87 and approximately 92%.
The process according to -the invention may be applied
with approximately equal results to linear olefins having -terminal
1- ~
~.~ll7~
or internal double bonds and to cyclic olefins. Wherl required,
the olefins used may also be branched and/or substituted b~
functional groups, for example, carboxyl groups. They can be
used as pure substances or asmixtures o hornologs or isomers.
Since a pressureless procedure is preferred in the process
according to the invention, the boiling points of the olefins
used must be above 40C. The process according to the invention
is particularly suitable for the hydroxylation of lony-chain
linear olefins containing 8 to 36 carbon atoms and a terminal
or internal double bond.
Monoo~lefins having terminal double bonds, i.e., so-
called ~-olefins, are usually obtained by means of the Ziegler
ethylene oligomerization process and primarily straight-chain
olefins having an even number of carbon atoms are formed.
Olefins containing up to approximately 18 carbon atoms can be
obtained commercially as pure substances. The olefins having
still longer chains are usually no longer obtained as pure
substances on the market but they are obtained as olefin
mixtures, for example, in the chain length range, C20 24~ C24 28
or C30~.
Monoolefins having internal double bonds are produced
industrially by dehydrogenation of paraffin fractions and,
therefore, normally constitute corresponding mixtures containing,
for example, 11 to 14 carbon atoms, in which the double bonds
are distributed statistically.
In the process according to the invention the hydrogen
peroxide may be used in a concentration of 35 to 98 percent
by weight, preferably in a concentration of 50 to 90 percent
by weight. It is favourable that the entire amount of hydroyen
peroxide is not added at first but if a mixture of olefin and
formic acid is used as the starting product, whereupon the hydrogen
peroxide is added in portiorls over 1 to ~ hours. The hydrogen
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peroxide may be added continuously or in portions, The gra~ual
addaition of hydrogen peroxide is recommended for safety reasons
particularly in cases in which it is used in a high concen-tration,
for example, of more than 50 percent by weight.
The reaction between the olefin and the performic
acid formed in situ is carried out at a temperature between 40
and 80C, preferably between 50 and 70C.
To attain a high yield it is sufficient if the
hydrogen peroxide is added in an amount of one mole per mole
of double bond. However, very high react~on rates associat~d
with good yields can be attained if the hydrogen peroxide is
used in a molar excess o 5 to 30%, relative to the content
of double bonds in the olefin used.
In the production of diols containing less than 16
carbon atoms the completion of the reaction between the olefin
and the performic acid formed in situ can usually be determined
from the fact that the reaction mixture becomes single-phase
or perhaps still shows a slight-degree of turbiditv. When
adding the hydrogen peroxlde gradually this state is attained
normally as early as directly after the completion of the
reaction. In the production of diols containing 16 or more
carbon atoms the reaction mixture usually remains two-phase.
This difference is taken into account in the processing
procedure preferred at any given time. From single-phase systems
the formic acid and the water are initially expelled suitably
at reduced pressure. Two-phase systems are initially sub~ected
with advantage to a phase separation. In the two cases the
organic phase can then be stirred once or several times with
water at elevated temperature and sep~rated from the aqueous
phase after cooling. If no phase separation occurs since the
diol formed is water-soluble to a ~reat extent, then the diol
is extracted with a suitable solvent, for example, ethyl acetate.
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Particularly pure diols are obtained when the organic phase is
reacted with alkaline-reacting substances. The organic phase
can thus be stirred for 15 minutes at elevated temperature,
for example, at 70~C, with a solution of caustic soda in amounts
such that the forrnic acid still present or set free by
saponification of the diol monoformates obtained is neutralized.
After separating the liquid phase and extracting the diol
formed hot water may be used for washing once or several times
until the crude diol or the extract is free from alkali. The
degree of purity of the crude products thus obtained, when
required after distilling off the extracting agent, usually
is so high that the crude products can be further used directly
for various reactions. If higher degrees of purity are required
in special cases, the crude products can easily be converted
into high-purity products by conventional measures such as
fractional distillation under reduced pressure or recrystallization
- from suitable solvents, for example, ethyl acetate.
The economic advantages of the process according to
the invention over the ]cnown process of Swern et al. lie in that,
for example,
1. the required reaction time is much shorter,
2. the further processing of the crude reaction
mixture is substantially facilitated due to the
use of smaller amounts of formic acid and of more
concentrated hydrogen peroxide since only
relatively small amounts of aqueous formic acid
~ust be removed from the system, and
3. the yields of pure diol are substantially higher.
The use of additional solvents in the reaction between
the olefin and the performic acid formed in situ is not required
since, at the reaction temperatures used, the olefins used and
the crude reaction products are liquid. However, in the subsequent
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treatment of the crude reaction products the use of additional
solvents may be advantageous in many cases in which the pure
diols ha~e a relatively high melting point. The crude reaction
products can then be diluted with solvents which have a high
solubility for the diols formed but only a slight solubili~y
in water and are resistant to saponification. Suitable solvents
are, for example, hydrocarbons or alcohols.
The process according to the invention is illustrated
in greater detail by the Examples hereafter.
Example 1
In a 4-litre stirring flask provided with a reflux
cooler mounted thereon and a dropping funnel 560 g (5 moles)
of ~-C8-olefin and 940 g (20 moles) of a 98% by weight formic
acid were mixed at a temperature of 50C. During 2 hours 340 g
(6 moles) of a 60 percent by weight hydrogen peroxide were added
in portions. After completed addition the ini-tially heterogeneous
system had become single-phase. The readily volatile components
(water and formic acid) were separated in a water jet vacuum
within half an hour at a bottom temperature o up t~ 110C.
The bottom product was then mixed with 2.6 litres of water, boiled
for 3 hours with reflux and separated from the aqueous phase.
Upon drying in vacuo 690 g of crude product which still had a
content of monoformate of 5.7 percent by weight were obtained.
The monoformate content was reduced to 0 percent by weight by
stirring with a 25 percent solution of caustic soda for 15
minutes at 70C. After separating the aqueous phase the crude
diol was purified b~ distillation. The fraction going over
at a temperature between 135 and 138C (12 torrs) weighed 635 g,
corresponding to a yield of pure diol of 87.0% of the
theoretical yield. The melting point of the pure diol was 35C.
For comparison the data of S~ern et al. show that the
pure diol obtained from ~-C8~olefin after a reaction time of 8
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hours at a temper~ture of 40DC and at a molar ratio of olefin
to formic acid of 1:9 had a meLting point of 30 to 30.5C
and the yield was 58% of the theoretical yield.
Example 2
The Example 1 was repeated with 840 g (5 moles) of ~-
C12-olefin and291 ~ (6 moles) of a 70 percent by weight hydrogen
peroxide at a reaction temperature of 55C. The yield of pure
diol was 90.5% of the theoretical yield and the melting point
of the pure diol was 61.5C.
For comparison, it is evident from the data of Swern
et al. that the pure diol obtained from ~-C12-olefin after a
reaction time of 24 hours at a temperature of 40C and at a
molar ratio of olefin to formic acid of 1:13 had a melting
point of 60 to 61C and the yield was 40% of the theoretical
yield.
Example 3
The Example 1 was repeated with 1120 g (5 moles) of
~-C16-olefin and 2~0 g (6 moles) of a 85 percent by weight
hydrogen peroxide at a reaction temperature of 60C. The yield
of pure diol was 93% of the theoretical yield and -the melting
point of the pure diol was 73.5~.
For comparison the data of Swern et al. show that the
pure diol obtalned from ~-C16-olefin after a reaction time
of 24 hours at a temperature of 40C and at a molar ratio of
olefin to formic acid of 1:31 had a melting point of 75 to 76C
a~d the yield was 58% of the theoretical yield~
Example 4
Analogously to Example 1, 175 g (~1 mole~ of a
technical olefin mixture,~which had an average chain length of
11 to 14 carbon atoms and in which the double bonds were
distributed statistically over the entire chain lengtht and 188
g (4 moles) of a 98 percent by weight formic acid were mixed
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in a l-litre stirring apparatus. In the course o~ 1 hour 61 g
(1.25 moles) of a 70 percent by weight hydrogen peroxide were
added in portions. Formic acid ana water were t11en separated
under reduced pressure and the bottoms from the distillation was
stirred with 165 g of a 25 percent by weight solution of caustic
soda for 15 minutes at 70C. The organic phase was separated,
washed twice with water (using 100 ml each time) and finally
subjected to a distillation at 0.1 torr. The fraction going
over at a temperature between 110 and 140~C weighed 186 g. This
corresponded to a yield of pure diol mixture of 89~ of the
theoretical yield. The melting point range of the mixture was
from 45 to 82C.
Example 5
In a l-litre stirring apparatus 252 g (1 mole) of
~-C18-olefin and 280 g (6 moles) of a 98 percent by weight
formic acid were mixed. In the course of 1 hour 52 g (1.3 moles)
of an 85 percent by weight hydrogen peroxide were added. Even
after a post-reaction time of one hour the system remained two-
phase and, therefore, it was subjected to a phase separation.
130 g of aqueous phase having a content of formic acid of appro-
ximately 80 percent by weight were thus separated. From the
organic phase 130 g of the product at the top were expelled at
reduced pressure. The bottoms obtained were mixed with benzene
in the ratio by volume of 1:2 and adjusted to neutral at 70C
with a 20 percent by weight solution of caustic soda. After
phase separation the organic phase was washed twice (using 100 ml
of water each time~ and subjected to fractional distillation
while cooling. The yield o~ pure diol, which had a melting
point of 78.5 to 79C, was 91.2% of the theoretical yield.
Example 6
A commercial ~-C20 24 olefin mixture having the
following composition was used as the starting product:
~ ~t~7~ ~ ~
~-C18-olefin approximately 1%
a-C20-olefin approximately 49%
~-C22-olefin approximatelY 42%
a-C24-Qlefin approximately 8~
According to the above composition, the commercial
product had an average molar weight of 306 and a melting point
~f 32C. In a l-litre stirring apparatus 306 g of olefin were
mixed with 280 g (6 moles) of a 98% formic acid and 48 g (1.2
moles) of an 85% H2O2 were added in the course of one hour. The
system was then stirred for an additional hour at 60C, whereupon
it was separated from the aqueous phase. The amount of formic
acid applied in excess was separated from the remaining
organic phase by dlstillation in vacuo (up to 90C at 12 torrs).
At a temperature of 90 to 100C the bottom product was then
stirred with 150 g of a 30% solution of caustic soda and
subsequently mixed with 600 ml of a-myl alcohol (to facilitate
separation of the two phases). The aqueous phase could be
drawn off readily while hot and the organic phase was washed
with 100 ml of water. The solvent (amyl alcohol) was removed
from the organic phase by distillation. The diol mixture-remain-
ing in the residue from distillation weighed 340 g and had a
residual olefin content of 5% and a solidification point of 76~C.
Example 7
An a-olefin mixture which is commercially obtainable
as C30+-olefin served as the starting product. The mixture is
assumed to have a content of a-C28-olefin of 22%, the rest being
C30 and still higher olefins. On the basis of the iodine
number an average molar weight of 453 was determined, corresponding
in turn to an average number of carbon atoms o~ approximately 32.
1 mole of olefin mixture C30+ was reacted as in Example
6 and further processed. Only the amount of the 30% solution of
caustic soda applied was reduced to 120 g. The diol mixture
~ 3
obtained (480 g) had a residual ole~in content o~ 10~ and a
solidification point of 90~C.
Example 8
. _
2 moles (136.2 g) of cyclopen-tene (b.p.760 = 44C)
were mixed with 8 moles (368 g) of a 98% formic acid in a stirring
apparatus (with reflux cooler mounted thereon). In the course
of 3 hours 2.4 moles (96.3 g) of an 85% H2O2 were added with
so-called "vapour cooling". The system, which had become
single-phase, was then stirred for further two hours at 45C,
whereupon it was freed from formic acid and reaction water by
distillation (at the end of the vacuum distillation a bottom
temperature of approximately 90C was attained at 12 torrs).
The bottom product was mixed with 2.2 moles of NaOH
(88 g disssolved in 200 ml of H~O2), cooled and extracted three
times consecutively at room temperature with a total of 400 ml
of ethyl acetate~ rhe combined extracts were freed from ethyl
acetate by distillation. 173 g of cyclopentane diol remained
as the residue from distillation corresponding to a yield of
85%. The yield of crude diol can be increased by further
extractions. The crude diol can be purified further by
recrystallization or by distillation (b.p.12 = 125 to 130C)-.
Example 9
1 mole (84 g) of neohexene (3,3-dimethyl butene-l,
- b.p.760 = 41C) was mixed with 4 moles (184 g) of a 98% formic
acid in a stirring apparatus and in the course of 1.5 hours,
1.2 moles (48 g) of an 85% H2O2 were added while vapour cooling.
The system, which had become single-phase, was stirred for a
further hour at 50C and then freed from 2.7 moles of formic
acid by distillation. The bottom product was saponified with 1.3
moles of NaOH (= 52 g dissolved in 120 ml of water), cooled and
extracted five times consecutively (using 100 ml o~ ethyl acetate
each time). The ethyl acetate was distilled from the combined
.3 ~ 3
extracts. 94 g of crude diol were obtained as the bottom product,
i.e. a yield of approximately 80%. The crude diol was then
converted into pure neohexane diol (solidification point - 38C)
by vacuum distillation (b.p.l5 = 105 to 110C).
Example 10
1 mole (282 g) of oleic acid was mixed with 4 moles
(184 g) of a 98% formic acid. In the course of one hour 1.1
moles (54 g) of a 70% H2O2 were added at 50C. After a further
hour the H2O2 content in the system, which had become single-
phase, dropped to 0.1%. The system was then freed from formicacid and water (up to 12 torrs and 90C at the bottom) by
distillation. The bottom product was dissolved at 70C with
400 g of a 25% NaOH. From the resulting Na salt~of the dihydroxy
stearic acid the acid was set free by mixing with 100 g of
concentrated HCl.
The liberated acid was separated in the molten state
from the aqueous phase and washed with 100 ml of H2O. Dissolved
water was removed by vacuum drying. 301 g of crude dihydroxy
stearic acid remained corresponding to a yield of approximately
95~. By recrystallization (for example, from ethyl acetate)
the crude acid can be ~onverted into a pure product (m.p. =
90 to 91C).
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