Organic compounds -- part of the class 532-570 series – Organic compounds – Azo
Reexamination Certificate
2001-09-19
2002-06-11
Powers, Fiona T. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Azo
C526S204000
Reexamination Certificate
active
06403774
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a useful azoamidine compound as a water soluble polymerization initiator.
In recent years in manufacturing of polymers, studies have been actively conducted how to complete a polymerization in higher concentration in shorter time for pursuing rationalization. In particular, in polymerization in an aqueous solution, polymerization temperature tends to become increasingly higher and polymerization time increasingly shorter year by year. Therefore, use of a conventional polymerization initiator such as redox initiator, persulfate compound, peroxide initiator and azo initiator tends to cause problems such as an increase of the amount of monomer remained by failing to complete the polymerization with due to too high activity of the initiator at the polymerization temperature.
In order to solve this problem, various methods have been studied, for example, by increasing an addition amount of an initiator, by adding an initiator in the middle of the reaction or by using multiple initiators having different activities in combination. However, these methods have still the following problems. The method by increasing an initiator amount has little effect due to decomposition of most of the initiator during polymerization, and the method by adding an initiator in the middle of the reaction also has a problem that the added initiator can not be sufficiently mixed due to an increase of viscosity of the polymerization solution.
And so, further methods have been proposed to solve this problem, for example, by using multiple polymerization initiators each having a different 10 hour half-life temperature corresponding to the temperature elevation range during the polymerization or by using an initiator having a decomposition activity corresponding to the polymerization temperature. However, in the method by using multiple polymerization initiators in combination, for example, the polymerization method using an azoamidine salt type polymerization initiator having a 10 hour half-life temperature of 45 to 60° C. (low temperature activity) and another azoamide salt type polymerization initiator containing hydroxy group and having a 10 hour half-life temperature of 80 to 90° C. (high temperature activity) together, there is still a problem that the polymerization reaction can not be well controlled. As another mean to solve this problem, it is considered to use an initiator having a decomposition activity corresponding to the conventional temperature elevation range (40 to 90° C.), namely, having a 10 hour half-life temperature of 60 to 70° C., however, such an initiator has not been found yet. Therefore, there is needed to develop a water soluble azo type polymerization initiator having a 10 hour half-life temperature of 60 to 70° C.
SUMMARY OF THE INVENTION
The present invention has been conducted based on the present situations as described above. And its object is to provide a novel azoamidine compound having a 10 hour half-time temperature of 60 to 70° C. in water which is useful as a water soluble polymerization initiator and enables to effectively polymerize various monomers in a polymerization in an aqueous solvent.
The present invention relates to a compound shown by the general formula [1]:
(wherein, R
1
and R
2
are each independently a hydrogen atom, a lower alkyl group or a cyano group, and
is an optionally substituted heterocyclic compound);
or a salt thereof (hereinafter referred to the azoamidine compound of the invention).
The present invention also relates to a polymerization initiator comprising the azoamidine compound of the invention.
The present invention further relates to a method for polymerizing an &agr;,&bgr;-ethylenically unsaturated monomer, wherein the azoamidine compound of the invention is used as a polymerization initiator.
The inventors of the present invention have extensively made study to attain the above objects, and found out that the azoamidine compound having a heterocyclic compound such as pyrrolidine ring in the molecule had the 10 hour half-life temperature in water of 60 to 70° C. and its use enabled more effective polymerization in an aqueous solvent than the conventional methods, and thus completed the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the general formula [1], the lower alkyl group shown by R
1
and R
2
may be linear chained, branched or cyclic, and includes a group having from 1 to 5 carbon atoms, preferably from 1 to 3 carbon atoms, and are specifically exemplified by a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a sec-pentyl group, a 2-methylbutyl group, a 1-ethylpropyl group, a 2-ethylpropyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group etc., and a methyl group is most preferable among others.
A heterocyclic compound which derives an optionally substituted heterocyclic compound shown by the following formula:
includes a 5-membered or a 6-membered ring compound irrespective of being saturated or unsaturated and having one or more nitrogen atom as a hetero atom, typically from 1 to 3, preferably one, and such a heterocyclic compound may further have typically one oxygen atom. Such a heterocyclic compound includes, for example, a saturated heterocyclic compound such as imidazolidine, pyrrolidine, pyrazolidine, piperidine, piperazine and morpholine; and an unsaturated heterocyclic compound such as pyrrol, pyrroline, imidazole, imidazoline, pyrazole, pyrazoline and triazole etc., among others, saturated heterocyclic compounds such as imidazolidine, pyrrolidine, pyrazolidine, piperidine, piperazine and morpholine are preferable, and pyrrolidine is most preferable.
Such a heterocyclic compound may have further substituents. Such a substituent is one which replaces a hydrogen atom of ring forming —NH— or similarly a hydrogen atom of —CH
2
— or ═CH—, and includes, for example, a lower alkyl group such as a methyl group, an ethyl group and an n-propyl group; a lower alkoxy group such as a methoxy group, an ethoxy group and an n-propoxy group; a halogen atom such as fluorine, chlorine, bromine and iodine etc.
A typical example of the azoamidine compound of the present invention shown by the above general formula [1] includes the followings:
Among which, the following compound is most preferable:
Further, such a typical compound may include a salt thereof. The salt includes one constituted with an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid and with lower carboxylic acids such as acetic acid, lactic acid and citric acid etc.
The azoamidine compound of the present invention can be prepared by reacting an azodiimino ether compound or a salt thereof shown by the following general formula [2]:
(wherein, R
3
is a lower alkyl group and R
1
and R
2
are the same as described above); with an amine compound shown by the following general formula [3]:
is the same as described above);
in an appropriate solvent or without any solvent:
In the general formula [2], the lower alkyl group shown by R
3
may be linear chained or branched, and includes a group having from 1 to 6 carbon atoms, preferably, from 1 to 4 carbon atoms, and are specifically exemplified by a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, a sec-pentyl group, a neopentyl group, an n-hexyl group, etc.
Typical examples of the azodiimino ether shown by the general formula [2] include, for example,
2,2′-azobis(1-imino-2-methylpropylmethylether),
2,2′-azobis(1-imino-2-methylpropylethylether),
2,2′-azobis(1-imino-2-methylpropyl-n-propylether),
2,2′-azobis(1-imino-2-methylpropylisopropylether),
2,2′-azobis(1-imino-2-methylpro
Hirose Seiji
Kondo Suguru
Shiraki Kazuo
Armstrong Westerman & Hattori, LLP
Powers Fiona T.
Wako Pure Chemical Industries Ltd.
LandOfFree
Azoamidine compound does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Azoamidine compound, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Azoamidine compound will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2976995