Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
1994-12-27
2002-10-22
Ford, John M. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C544S209000
Reexamination Certificate
active
06469165
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improved process for preparing linear polyaminotriazines. More particularly, polyaminotriazines represented by the formula (I):
wherein n is a number from 2 up to 20; X
1
, X
2
, X
3
and X
4
, which are same or different, are each hydrogen or a piperidyl represented by formula (Ia):
wherein R
1
is a hydrogen atom, C
1
to C
12
alkyl, C
1
to C
18
alkoxy, C
3
to C
8
alkenyl, C
7
to C
11
arylalkyl or C
3
to C
5
alkenyloxy, provided that 75 mole % or more of X
1
, X
2
, X
3
and X
4
is piperidyl represented by formula (Ia); R is C
2
to C
12
alkylene which can be interrupted by —O— or —NR
2
—, wherein R
2
is hydrogen, C
1
to C
12
alkyl, C
3
to C
12
cycloalkyl or a piperidyl represented by formula (Ia), or R is a divalent C
6
to C
15
cycloaliphatic group; and Q is —OR
3
, —NHR
4
or —NR
4
R
5
, wherein R
3
is C
1
to C
12
alkyl, C
5
to C
12
cycloalkyl, benzyl, phenyl, tolyl or piperidyl represented by formula (Ia), R
4
is C
1
to C
12
alkyl, C
3
to C
12
alkoxyalkyl, C
4
to C
12
N,N-dialkylaminoalkyl, C
3
to C
5
alkenyl, phenyl, benzyl, cyclohexyl, tolyl or piperidyl represented by formula (Ia), and R
5
is C
1
to C
12
alkyl or cycloalkyl, or R
4
and R
5
together form a tetra or pentamethylene group (e.g. together with the N atom to which they are bonded, R
4
and R
5
form a 5- or 6-membered heterocyclic ring) are prepared in accordance with the present invention.
These compounds are useful as light stabilizers for organic materials, and are particularly useful for stabilizing synthetic resins.
BACKGROUND OF THE INVENTION
It is known that organic materials, such as synthetic polymers, i.e., polyethylene, polypropylene or the like, are liable to undergo a deterioration of their properties, such as softening, embrittlement and discoloration, when they are exposed to light. In order to prevent such deterioration, various stabilizers, including polyaminotriazines, have been proposed.
Various methods for preparing polyaminotriazines are known to those skilled in the art.
According to JP-A-52-71486, polyaminotriazines are usually prepared by polycondensation of a monopiperidylamine or dipiperidylamine represented by the formula (II):
X—NH—R—NH—X
5
(II)
wherein R can be as defined above, X can be piperidyl represented by formula (Ia) and X
5
can be hydrogen or piperidyl represented by formula (Ia), with a dichlorotriazine represented by formula (III):
wherein Q can be as defined above, in an inert solvent from −10° C. up to the solvent boiling temperature in the presence of an inorganic or organic base.
In more detail, this reaction is carried out mainly in toluene under refluxing conditions and in the presence of sodium hydroxide. Since the reaction mixture contains water generated from the reaction, the reflux is usually actually conducted at a temperature about 10° C. lower than the boiling point of toluene. The polyaminotriazines are obtained from the resultant reaction mixture by filtering off the by-products and sodium chloride, and by evaporating off the solvent.
The process of JP-A-52-71486, however, is disadvantageous in that the reaction hardly proceeds to completion, and that sparingly soluble by-products having a high melting point are formed. These by-products are sparingly soluble in the synthetic resins to be stabilized by the polyaminotriazines. These by-products can deteriorate the synthetic resins, and thus reduce the commercial value of the resin products. As a consequence, the conventionally produced polyaminotriazines containing the by-products are undesirable as stabilizers. Therefore, to obtain useful stabilizers, it has proven necessary to remove the by-product contaminants from the resulting reaction mixture, such as by filtration. However, the separation can drastically and adversely reduce the yield. For instance, the polyaminotriazine yield decreases to only about 70-75% after the by-products, at least some of which are fine powdery materials, have been separated off by filtration.
The process of JP-A-52-71486 has yet another disadvantage in that only polycondensates having relatively low polycondensation degree of less than 6 are reportedly obtained. These polyaminotriazines are not particularly desired for use as stabilizers. Polyaminotriazines having a polycondensation degree of 6 or more are preferred, and a polycondensation degree of 7 to 11 is even more preferred, when the compounds are used as a stabilizer for a synthetic resin exposed to the atmosphere (open air) or the like.
Another process for the preparation of polyaminotriazines is described in JP-A-58-210820. According to JP-A-58-201820, the polyaminotriazines represented by formula (I) are prepared by a polycondensation of a dichlorotriazine represented by formula (III), which is obtained by a substitution of a chlorine atom of cyanuric chloride with a radical such as amine, with a diamine represented by formula (II) in a water-immiscible inert solvent at a temperature of from 140° C. to 220° C. at an elevated pressure in the presence of an aqueous solution of an inorganic base.
In an example of the process of JP-A-58-210820, the polycondensation reaction is conducted in a two-phase system of xylene/water at an elevated pressure at a temperature of about 185° C. in the presence of a concentrated aqueous solution of sodium hydroxide. The resultant reaction mixture is subjected to phase-separation, washing and oil-water separation to obtain a xylene phase, which is, then, filtered to remove the by-products.
Polyaminotriazines are obtained from the resulting filtrate by evaporating off the solvent. According to this known process, the polyaminotriazine may be obtained at a theoretical yield of 93-96% based on the amount of the diamine of formula (II), but nonetheless there are several significant disadvantages.
One disadvantage is that a special and high-priced material which is alkaline- and heat-resistant must be used for the reaction vessel because the reaction is carried out at high temperature, under alkaline conditions, under high pressure, and in the presence of water. These conditions are so severe that even SUS 316L, which has been widely used for pressure reaction vessels, is eroded. Therefore, even SUS 316L cannot be used for the reaction vessel.
Another disadvantage is that polyaminotriazine products having a low polycondensation degree are liable to be obtained because the reaction components can come in contact with water. The chlorotriazine intermediate of this reaction is hydrolyzed at a high temperature of about 185° C. when it comes in contact with water. However, in this known process, the reaction is carried out in a two-phase system which includes water.
Hitherto, in addition to the already noted drawbacks, the preparation of the polyaminotriazines represented by formula (I) from the diamine represented by formula (II) and the dichlorotriazine represented by formula (III) has been carried out independently from the preparation of the diamine represented by formula (II). For instance, conventionally, the dipiperidylamine represented by formula (II) is prepared by a reaction between a tetramethylpiperidone represented by formula (IIa) and diamine represented by formula (IIb) has been isolated from the resulting reaction mixture before being used for the preparation of the polyaminotriazines represented by formula (I). More particularly, the diamine represented by formula (II) has been prepared by reacting a tetramethylpiperidone represented by formula (IIa):
wherein R
1
is as defined above, with a diamine represented by formula (IIb):
NH
2
—R—NH
2
(IIb)
wherein R is as defined above, and the diamines have then been refined and purified. Diamines and various methods of their preparation are described in JP-B-58-11454, JP-A-64-50858, and JP-A-5-86029.
Without the isolation and refinement of the dipiperidylamine represented by formula (II), it has heretofore been thought that the polyaminotriazines represented by formula (I) having sufficient properties a
Kimura Kenji
Sasaki Manji
Tanaka Shinya
Balasubramanian Venkataraman
Fitch Even Tabin & Flannery
Ford John M.
Sumitomo Chemical Company Limited
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