Note: Descriptions are shown in the official language in which they were submitted.
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A PROCESS FOR THE PREPARATION OF
AMINOPOLYALKYLFNE OXIDES
BACKGROUND OF THE INVENTION
This invention relates to a process for the
preparation of aminopolyalkylene oxides by reductive amination
of hydroxypolyalkylene oxides in the presence of Raney nickel
or Raney nickel/iron or Raney cobalt (hereinafter referred to
as Raney catalysts) in admixture with aluminum powder as
catalyst.
lo Raney nickel, Raney nickel/iron, or Raney cobalt are
suitable for the reductive amination of compounds containing
hydroxyl groups. See, for example Houben-Weyl XI/l (1957),
pages 108-134.
U.S. Patent 4,766,245 describes the use as a catalyst
for reductive amination of Raney nickel containing residual
aluminum from the starting alloy after treatment with sodium
hydroxide. In this catalyst, the aluminum is the embedding
material, or rather the support, for the catalytically active
nickel and does not contact atmospheric oxygen in this form.
It has now surprisingly been found that the activity
of Raney nickel, Raney nickel/iron, or Raney cobalt can be
considerably increased by the sole addition of aluminum powder.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to a
simplified amination process for the preparation of
aminopolyalkylene oxides comprising reacting
(a) hydroxypolyalkylene oxides,
(b) ammonia and/or primary or secondary amines, and
(c) hydrogen gas,
30 - i n the presence of
(d) a mixture of
(i) Raney catalysts and
(ii) 1 to 50 percent by weight, based on the Raney
catalyst, of aluminum powder as co-catalyst.
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DETAILED DESCRIPTION OF THE INVENTION
It was particularly surprising to find that the
catalytic activity of the Raney catalyst could be considerably
increased by the simple addition of aluminum powder, even after
the aluminum has been exposed to air for several weeks and thus
no intimate contact (such as would be found in an alloy with
the catalytically active metal) can be expected. The aluminum
powder may be introduced into the reaction mixture either as a
mixture with the Raney catalyst or separately before or after
addition of the Raney catalyst. The aluminum powder is used in
a particle size of from about 4 to about 100 ~m, preferably
from 10 to 50 ~m. The quantity of aluminum powder ranges from
about 1 to about 50 percent by weight, based on the quantity of
Raney catalyst.
Suitable hydroxypolyalkylene oxides used in the
reductive amination process according to the invention are
known hydroxypolyethers corresponding to the general formula
R[-(A)-~]m
wherein
R is an m-functional residue of a Zerewitinoff-active
compound obtainable by removal of m active hydrogen atoms;
A is a chain of linear and/or branched alkylene groups
interrupted by oxygen atoms and having an average
molecular weight (Mn) in the range from about 500 to about
10,000; and
m is a number from 1 to 4.
Compounds of this type are described, for example, in British
Patent 971,173.
Preferred hydroxypolyalkylene oxides are those in
which R is a phendioxy group obtainable by removal of two
phenolic hydrogen atoms. The phenolic OH groups from which the
hydrogen atoms are removed may be located on one benzene ring
or on two benzene rings in the same molecule. Examples of
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suitable compounds of this type include hydroquinone, 4,4'-
diydroxybiphenyl, 4,4'-dihydroxydiphenylmethane, 2,2-bis(4-
hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-
bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)-
cyclohexane, 1,1-bis(4-hydroxyphenyl), 4,4'-dihydroxystilbene,
4,4'-dihydroxytolane, 4,4'-dihydroxydiphenyl ether, 3,3'-di-
hydroxydiphenyl ether, 1,4-dihydroxynaphthalene, 1,5-dihydroxy-
naphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaph-
thalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,
1,4-bis(2-hydroxyethoxy)benzene, 1,5-bis(2-hydroxyethoxy)-
naphthalene, and 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane.
Although compounds in which R is a phendioxy group are
preferred, it is not essential for R to be a phendioxy group.
Suitable hydroxypolyethers can be prepared, for
example, from cyclic oxides, such as ethylene oxide, propylene
oxide, butylene oxide, or tetrahydrofuran, in the presence of a
catalyst and optionally in the presence of a compound
containing several active hydrogen atoms (such as the preferred
phendioxy compounds discussed above). See Encvclopedia of
PolYmer Science and TechnoloqY, Vol. 6, pages 103-209, or Vol.
13, pages 670-689, Interscience Publishers, Inc., 1969. In any
given hydroxypolyether, the alkylene groups need not all be
identical. The alkylene groups may optionally be linear and/or
branched (i.e., linear with alkyl substitution) and can be
added randomly or in a particular sequence, depending on the
quantity and sequence in which the cyclic oxides are added.
The amination reaction to form amine-terminated
polyethers from the corresponding hydroxypolyethers takes place
in the presence of ammonia, hydrogen, and the catalyst mixture
of Raney nickel or Raney nickel/iron or Raney cobalt and
aluminum powder. It is preferred to use ammonia as solvent.
When carrying out the amination reaction, 4 to 150 mole of
ammonia and 0.5 to 10 mole of hydrogen are used per hydroxyl
group of the polyether. In addition to ammonia, certain
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amines, preferably methylamine, dimethylamine, and morpholine,
can be used for the process of the invention.
The reaction is conducted at temperatures in the
range from about 140 to about 250C at a pressure of about 35
to about 350 atms gauge pressure ~preferably 140 to 180 atms
gauge pressure). When using a batch process, the reaction
times are in the range from about 0.5 to about 20 hours. When
using a continuous process, the throughput rate should be about
0.1 to about 1.5 9 of starting hydroxypolyether per cm3 of
catalyst per hour.
The compounds prepared according to the invention are
particularly suitable as a chain-extending agent for polyurethane
plastics and epoxides, as epoxy hardener, as a component of
adhesives, as a modifier in polyamides, as a component in
surface-active compounds (e.g., emulsifiers or antistatic
finishing of textiles), or as a lubricating oil additive.
The following examples further illustrate details for
the process of this invention. The invention, which is set
forth in the foregoing disclosure, is not to be limited either
in spirit or scope by these examples. Those skilled in the art
will readily understand that known variations of the conditions
of the following procedures can be used. Unless otherwise
noted, all temperatures are degrees Celsius and all percentages
are percentages by weight.
EXAMPLES
ExamPle 1
A polytetrahydrofuran having an OH number of 56
(1,500 9) was introduced into a 3 liter stirred autoclave at
room temperature with 55 g of Raney Ni/Fe (70:30) (as disclosed
e.g. in U.S. Patent Nb. 4,287,365) and 5.5 g of aluminum powder.
After purging with hydrogen, liquid ammonia (380 ml)
was introduced and a hydrogen pressure of 30 bar was
established. The reaction mixture was heated with stirring to
225C, with the pressure rising to approximately 180 bar.
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After 20 hours at 225C, the autoclave was cooled and
vented. The Raney Ni/Fe was filtered off and the filtrate was
freed from volatile constituents (such as ammonia and water) in
vacuo at 150C.
The NH2 content was 1.39% by weight, corresponding to
a degree of amination of 87% (as determined by titration with
1 N HCl using bromphenol blue as indicator).
Comparison for Example 1
The corresponding amination of polytetrahydrofuran
(OH value 56) without Al powder led to an NH2 content of 1.18%
by weight, corresponding to a degree of amination of 74%:
Example 2
A polyethylene glycol having an OH number of 14
(1,500 9) was aminated as described in Example 1. The
15 resultant product had an NH2 content of 0.40% by weight,
corresponding to a degree of amination of 100%.
ComDarison for Exam~le 2
The corresponding amination without Al powder gave an
NH2 content of 0.30% by weight, corresponding to a degree of
20 . amination of 75%.
Example 3
A bis(4-hydroxyphenyl)methane-started polypropylene
glycol having an OH number of 112 (1,500 9) was aminated as in
Example 1. The resultant product had an NH2 content of 2.85%
25 by weight, corresponding to a degree of amination of 89%.
Comparison for Example 3
The corresponding amination without Al powder gave an
NH2 content of 1.69% by weight, corresponding to a degree of
amination of 53%.
30 ExamDle 4
A bis(4-hydroxyphenyl)methane-started polypropylene
glycol having an OH number of 112 (1,500 9) was aminated in the
same way as in Example 3, except that 2.75 9 of aluminum powder
was used instead of 5.5 9 of aluminum powder. The reaction
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product had an NH2 content of 2.30% by weight, corresponding to
a degree of amination of 72%.
Example 5
A bis(4-hydroxyphenyl)methane-started polypropylene
glycol having an OH number of 112 (1,500 g) was aminated in the
same way as in Example 1, except that 55 g Raney nickel was
used instead of 55 g Raney Ni/Fe. The resultant product had an
NH2 content of 2.63% by weight, corresponding to a degree of
amination of 82%.
o ComParison for Example 5
The corresponding amination without the Al powder
gave an NH2 content of 1.92% by weight, corresponding to a
degree of amination of 60%.
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