CA1251795A - Process for synthesizing 2-vinyl-4,6-diamino-s- triazine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

2-Vinyl-4,6-diamino-s-triazine is synthesized in a high yield by reacting 2-(2'-methylimidazolyl-(1'))-ethyl-4,6-diamino-s-triazine with epichlorohydrin. The reaction may be carried out in an aqueous medium in the presence of a catalytic amount of a polymerization inhibitor. The product is useful as a comonomer.

Description

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PROCESS FOR SYNTHESIZING 2-VINYL-4,6-DIAMINO-s-TRIAZINE

Background of the Invention Field Or the Invention:
This invention relates to a process for synthesizing 2-vinyl-4,6-diamino-s-triazine (to be abbreviated as VT).
Description Or the Prior Art:
VT is a compound represented by the rollowing structural formula, and has vinyl-polymerizability.

CH2 = CH - ~ ~ N
N ~

(VT) VT has a melting point Or 239 to 241 C, and is soluble in ho-t water but sparingly soluble in hot methanol, hot ethanol and hot acetone. It is almost neutral. When VT is dissolved in hot water and azobisisobu-tyronitrile is added, a polymer insoluble in hot water is formed.
TLC (alumina and silica, EtOH): Rf = 0.0 -1 334, 3170, 1680 (4th absorption), 1655 (2nd absorption), 1550 (lst absorption), 1460 (5th absorption), 1425 (3rd absorption), 1370, 1265, 1130, 985, 960, 835 (6th absorption).
NMR (d6-DMSO):~ 6.76 (m, 4H), 6.35-6.45 (t, 2H), 5.59-5.72 (q, lH).

~5~7~

- 2 -Elementary analysis: C 44.28%, H 5.07%, N 50.02%.
VT is useful as a comonomer. It is known that when diamino s-triazine-group is introduced into a side chain of a polymer, the softening point and glass transition point Or the polymer become much higher than the original polymer, its specific gravity also increases, and its solubility changes remarkably (see, for example, Seo and . Kakurai: Collection of Papers on Polymers (the Japanese-language publication), 32, 308 (1975); T. Seo, K. Abe, H. Honma, T. Kakurai: Polym. Prepn., 20, 661 (1979)).
Various methods have already been known for the synthesis of VT. They include, for example, the reaction of biguanide with acryloyl chloride (C. G. Overberger et al.: J. A. C. S., 80, 988 (1958)), the reaction of dicyandiamide with B-dimethylamino-propionitrile (Hoechst, French Patent 1,563,255 (1967)), the heating of 1,2-di(4',6'-diamino-s-striazinyl-(2)')-cyclobutane to 320 C under reduced pressure (Asahi Chemical Industry, Co., Ltd.: Japanese Patent Publication NO. 35068/1971), and the heating of 2-B-me-thoxye-thyl-4,6-diamino-s-triazine to 350 C in a stream of nitrogen (Suddeutsche Kalkstickstoff Werke A.G.: German OLS 2,135,881 (1973)).
None of'-these prior methods for the synthesis of VT, however, lend themselves to industrial-scale practice for one or more reasons. For example, the starting materials are expensive, the reaction operation is complex, or the yield of VT is low.
SUMMARY OF THE INVENTION
The present inventors have now found that VT can be obtained in a high yield by reacting 2-(2'-methylimidazolyl-(l'))-ethyl-4,6-diamino-s-triazine (to be abbreviated as 2MA) with epichlorohydrin at an elevated temperature in an aqueous medium.

This reac-tion :is schema-ticaly shown as follows:-~ N ~ 2 2 ~ N + C~-CH2-CH - CHz H2N CH3 o 2MA epichlorohydrin H2N ~ /
N ~ ~ CH=CH2 ~ N~ N-CH2-CH-CH2OH
~== N HC~ , ~ I
H2N ~ CH3 OH

~ y-dihydroxy)-propyl-2-methylimidazole hydrochloride DE'I'AILED DESCRIPTION OF PREFERRED EMBODIMENTS
The starting 2MA in the above reactlon is a compound which can be obtained in good yields from acrylonitrile, 2-methylimidazole and dicyandiarnide by the method described in Japanese Patent Publication No.
36391/1972.
The other starting material, epichlorohydrin, is a compound which is produced in quantities as a material

3 for general-purpose epoxy resins.
In one preferred embodiment, a starting mixture composed of 1 mole of 2MA, 1 mole of epichlorohydrin, a small amount (i.e., a catalytic amount) of a

4 ~5~ 5 polymerization inhibitor such as Na2S 9H20 and a suitable amount of water is heated under reflux ror 30 minutes wi-th stirring (when heated, the mixture becomes a complete solution, and then crystals begin to precipitate from it).
The resulting reaction mixture is cooled, and the crude product (VT) is collected by riltration.
Recrystallization of the crude product in a customary manner gives the final desired product in pure form.
Various commercial polymerization inhibitors, such as hydroquinone and sodium sulfide (Na2S~9H20), can be used, but the use of sodium sulfide is most economical.
EXAMPLE
A starting mixture composed of 0.1 mole (21.9 g) of 15 2M~, 0.1 mole (9.25 g) of epichlorohydrin, a catalytic amount of sodium sulfide (Na2Sr9H20) and 50 mQ of water was heated under reflux for 30 minutes with stirring.
The resulting reaction mixture was cooled, and 0.1 mole (13.7 g; the yield was quantitative) Or the crude product (vr~') was collected by filtration. Since the crude product showed a mel-ting point of 237 to 240 C
which is much the same as the rnelting point Or an authentic sarnple of VT, it was considered to be VT
having a considerably high purity.
The crude product was recrystallized from water containing a small amount Or sodium sulfide to give 0.076 mole (10.4 g; yield based on 2MA 76 mole%) Or the purified product. The product had a melting point of 239 to 241 C.
The filtrate left after the recovery of the crude product was neutralized with sodium carbonate. The sodium ion in the neutralized liquid was removed by a sulfonic acid-type ion exchange resin, and then it was ~ 7

5 -concentrated under reduced pressure. The residue was chromatographed on a silica column to give 0.06 mole (9.4 g; yield based on 2MA 60 mole%) of l-(~,y-dihydroxy)propyl-2-methylimidazole.
1-(~,y-Dihydroxy)propyl-2-methylimidazole had the rollowing properties.
Melting point: > 250 C
Colorless and resinous. Basic.

~KBrl :1620 (6th absorption), 1585 (3rd absorption), 1520 (2nd absorption), 1415 (2nd absorption), 1255 (2nd absorption), 1100 (lst absorption), 1025 (5th absorption), 860 (5th absorption), 750 (4-th absorption).
NMR (D20):~ 7.50 (s, 2H(pro-tons at -the lJ-and 5-posi-tions o~ imidazole)), Ll,34 (m, 5H (propyl group)), 2.72 (s, 3}l (methyl group)).

Claims (6)

THE EMBODIMENT OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for syntyhesizing 2-vinyl-4,6-diamino-s-triazine represented by the structural formula which comprises reaction 2-(2'-methylimidazolyl(1'))-ethyl-4,6-diamino-6-triazine represented by the structural formula with epichlorohydrin represented by the structural formula

2. The process of claim 1 wherein 2-(2'-methyimidazolyly(1'))-ethyl-4,6-diamino-s-triazine and epichlorohydrin are reacted in substantially equimolar proportions.

3. The process of claim 1 wherein the reaction is carried out in an aqueous medium in the presence of a catalytic amount of a polymerization inhibitor.

4. The process of claim 3 wherein the polymerization inhibitor is sodium sulfide.

5. The process of claim 3 wherein the reaction is carried out by heating the starting compounds under reflux.

6. The process of claim 1 wherein 2-vinyl-4,6-diamino-s-triazine is separated in the form of crystals from the reaction mixture after the reaction.