JP4321786B2 - Preparation of 2-hydroxy-4,6-diaryl-s-triazine - Google Patents

Description

【化２】

但し、化１及び化２中のＲ_１、Ｒ_２、及びＲ_３は、各々独立に水素原子、炭素原子数１〜１８のアルキル基、アルコキシ基、ハロゲン原子又はヒドロキシル基を表す。
【００１０】
Ｒ₁〜Ｒ₃で表されるアルキル基としては、例えば、メチル、エチル、プロピル、ブチル、第三ブチル、ペンチル、ヘキシル、ヘプチル、オクチル、ノニル、デシル、ウンデシル、ドデシル、トリデシル、テトラデシル、ペンタデシル、ヘキサデシル、ヘプタデシル、オクタデシルなどが挙げられる。アルコキシル基としては、上記アルキル基に対応するアルコキシル基が挙げられる。
【００１１】
本発明に用いられる炭酸エステルとしては、炭酸ジメチル、炭酸ジエチル、炭酸ジプロピル、炭酸ジブチルなどのジアルキル炭酸エステル、炭酸ジフェニルなどのジアリール炭酸エステルなどが挙げられる。ジアリール炭酸エステルは反応性に優れ、反応温度、反応時間、収率で優位である。また、炭酸ジメチルは、同一モル数用いた場合に、配合重量では最も少量であり、同じ容積の反応槽で合成した場合に、収量の点で最も有利となる。
【００１２】
ベンズアミジン化合物と炭酸エステルの配合比（ベンズアミジン化合物／炭酸エステル）は、２／１〜１／４（モル）が好ましく、１／１〜１／２がより好ましい。この範囲を外れると、生産効率が低下する。
【００１３】
反応温度としては、室温〜２２０℃が好ましく、室温〜１９０℃がより好ましい。反応初期では室温〜５０℃で、反応終点では１６０〜２２０℃で反応させることが好ましい。この範囲を外れると、反応時間が長くなったり、目的化合物の生成率が低かったり、副生物により精製が困難になるなどの問題が起きる。
【００１４】
本発明の反応においては、反応時間の短縮と収率の向上のために酸中和剤を用いることが好ましい。酸中和剤としては、例えば、水酸化リチウム、水酸化ナトリウム、水酸化カリウムなどのアルカリ金属水酸化物、リチウムメトキサイド、ナトリウムメトキサイド、カリウムメトキサイド、ナトリウムエトキサイド、ナトリウムプロポキサイド、ナトリウムブトキサイド、ナトリウム−ｔ−ブトキサイドなどのアルカリ金属アルコキサイド、リチウムアミド、ナトリウムアミドなどのアルカリ金属アミドが用いられる。酸中和剤はベンズアミジン化合物に対し、０．９〜１．３モル使用することが好ましく、等モル用いることがより好ましい。
【００１５】
また、本発明の反応は、溶剤を用いても用いなくてもよい。溶剤を用いる場合は、例えば、水、メタノール、エタノール、プロピルアルコール、アセトン、テトラヒドロフラン、ジメチルホルムアミド、ジメチルスルホキサイドなどの極性溶媒、ヘキサン、ヘプタン、シクロヘキサンなどの脂肪族炭化水素系溶媒、ベンゼン、トルエン、キシレンなどの芳香族炭化水素系溶媒などを用いることができる。
【００１６】
酸中和剤を用いる場合に生成する塩は、例えば、反応の途中又は反応後に塩が析出し、目的化合物が溶解する溶剤や温度条件下でろ別し、次いで反応混合物の温度を下げて目的化合物を単離することができる。
【００１７】
【実施例】
以下、実施例により本発明をより詳細に示す。ただし、本発明は以下の実施例によりなんら制限を受けるものではない。
【００１８】
（実施例１）
ベンズアミジン塩酸塩４０ｇ（純度９４％、０．２４モル）をメタノール４０ｇに溶解し、この溶液に２８％ナトリウムメトキサイドメタノール溶液４６．３ｇ（０．２４モル）を室温にて滴下した。その後ジメチル炭酸エステル４３．２ｇ（０．４８モル）を加え、室温にて７時間攪拌した。さらに、４０℃で減圧し、４．５時間かけてメタノールを留去させた。その後ソルベッソ１５０を１２０ｇ加えて、４０℃まで昇温したのち、ろ過にて反応系内の塩化ナトリウムを取り除いた。さらに溶液を１７５℃にて２時間反応させた後、室温まで冷却し沈殿した生成物をろ過単離し、メタノールで洗浄して、微黄色粉末１８．４ｇ（収率６１．４％）を得た。
【００１９】
得られた化合物は、融点２９８℃であり、赤外吸収スペクトルにより目的物（２−ヒドロキシ−４，６−ジフェニル−ｓ−トリアジン）であることを確認した。
【００２０】
赤外吸収波長（ｃｍ^-1）は、３４３０、２９００、１６５０、１５３０、１４８０、１３６０、９９０、７１０であった。
【００２１】
（実施例２）
ベンズアミジン塩酸塩４０ｇ（純度９４％、０．２４モル）をメタノール４０ｇに溶解し、この溶液に２８％ナトリウムメトキサイドメタノール溶液４６．３ｇ（０．２４モル）を室温にて滴下した。その後ジフェニル炭酸エステル１０３ｇ（０．４８モル）を加え、室温にて７時間反応させた。さらに、４０℃で減圧し、４．５時間かけてメタノールを留去させた。その後ソルベッソ１５０を１２０ｇ加えて、４０℃まで昇温したのち、ろ過にて反応系内の塩化ナトリウムを取り除いた。さらに溶液を１７５℃にて２時間反応させた後、室温まで冷却し沈殿した生成物をろ過単離し、メタノールで洗浄して、微黄色粉末２１．９ｇ（収率７３．３％）を得た。
【００２２】
得られた化合物は、融点２９８℃であり、赤外吸収スペクトルは実施例１と同様であったことにより同じ目的物であることを確認した。
【００２３】
【発明の効果】
本発明により、ホスゲンやクロロ蟻酸エステルなどの毒性、腐食性に問題を有する化合物を用いることなく２−ヒドロキシ−４，６−ジアリール−ｓ−トリアジンを製造できる。[0001]
The present invention relates to a process for producing 2-hydroxy-4,6-diaryl-s-triazine. More specifically, the present invention relates to a method for producing 2-hydroxy-4,6-diaryl-s-triazine, which comprises reacting a benzamidine compound with a carbonate ester.
[0002]
BACKGROUND OF THE INVENTION
2-Hydroxy-4,6-diaryl-s-triazine is a synthetic intermediate such as triaryltriazine useful as an ultraviolet absorber.
[0003]
[Prior art and problems to be solved by the invention]
Conventionally, as a method for synthesizing 2-hydroxy-4,6-diaryl-s-triazine, it can be synthesized from amidine and chloroformate ester or phosgene. Ber. 23, 2934 (1890). Japanese Patent Application Laid-Open No. 5-70433 proposes to improve the yield by using a benzamidine hydrohalide as the amidine.
[0004]
However, the conventional production method using chloroformate ester or phosgene has problems in terms of corrosion of equipment and safety of workers.
[0005]
[Means for Solving the Problems]
As a result of intensive studies in view of the above situation, the present inventors have found that 2-hydroxy-4,6-diphenyl-s-triazine can be obtained from benzamidine and a carbonic acid ester compound, and have reached the present invention.
[0006]
That is, the present invention uses benzamidine or a benzamidine having a substituent (hereinafter, both are referred to as benzamidine compounds) and a carbonic acid ester compound, so that the apparatus does not corrode and is excellent in worker safety. A method for producing a 4,6-diaryl-s-triazine compound is provided.
[0007]
The present invention is described in detail below.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Oite the present invention, hydrohalides benzamidine compound or said compound represented by the following formula of 1 is used. The benzamidine compound represented by the formula 1, a phenyl group having a phenyl group or a substituent represented by the following formula 2, "A 2-hydroxy-4,6-diaryl -s- triazine target compound It corresponds to “reel”.
One type of benzamidine compound is usually used, but two or more types may be mixed and used.
[0009]
[Chemical 1]

[Chemical formula 2]

However, of the first and of in 2 R _{1, R} 2, and R ₃ each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group, a halogen atom or a hydroxyl group.
[0010]
Examples of the alkyl group represented by R _{1 to} R ₃ include methyl, ethyl, propyl, butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, Hexadecyl, heptadecyl, octadecyl and the like can be mentioned. As an alkoxyl group, the alkoxyl group corresponding to the said alkyl group is mentioned.
[0011]
Examples of the carbonate used in the present invention include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate and dibutyl carbonate, and diaryl carbonates such as diphenyl carbonate. Diaryl carbonates are excellent in reactivity and are superior in reaction temperature, reaction time and yield. Further, dimethyl carbonate has the smallest blending weight when the same number of moles is used, and is most advantageous in terms of yield when synthesized in a reaction vessel having the same volume.
[0012]
The blending ratio of the benzamidine compound and the carbonate ester (benzamidine compound / carbonate ester) is preferably 2/1 to 1/4 (mole), more preferably 1/1 to 1/2. Outside this range, the production efficiency decreases.
[0013]
The reaction temperature is preferably room temperature to 220 ° C, more preferably room temperature to 190 ° C. The reaction is preferably performed at room temperature to 50 ° C. at the beginning of the reaction, and at 160 to 220 ° C. at the end of the reaction. Outside this range, problems such as longer reaction time, lower production rate of the target compound, and difficulty in purification due to by-products occur.
[0014]
In the reaction of the present invention, it is preferable to use an acid neutralizing agent in order to shorten the reaction time and improve the yield. Examples of the acid neutralizer include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, lithium methoxide, sodium methoxide, potassium methoxide, sodium ethoxide, sodium propoxide, sodium Alkali metal alkoxides such as butoxide and sodium-t-butoxide, and alkali metal amides such as lithium amide and sodium amide are used. The acid neutralizer is preferably used in an amount of 0.9 to 1.3 moles, more preferably equimolar, relative to the benzamidine compound.
[0015]
The reaction of the present invention may or may not use a solvent. When using a solvent, for example, polar solvents such as water, methanol, ethanol, propyl alcohol, acetone, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, aliphatic hydrocarbon solvents such as hexane, heptane, cyclohexane, benzene, toluene An aromatic hydrocarbon solvent such as xylene can be used.
[0016]
The salt produced when the acid neutralizer is used is, for example, filtered out under the solvent or temperature conditions in which the salt precipitates during the reaction or after the reaction and the target compound dissolves, and then the temperature of the reaction mixture is lowered to lower the target compound. Can be isolated.
[0017]
【Example】
Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited by the following examples.
[0018]
Example 1
40 g (purity 94%, 0.24 mol) of benzamidine hydrochloride was dissolved in 40 g of methanol, and 46.3 g (0.24 mol) of 28% sodium methoxide methanol solution was added dropwise to this solution at room temperature. Thereafter, 43.2 g (0.48 mol) of dimethyl carbonate was added and stirred at room temperature for 7 hours. Further, the pressure was reduced at 40 ° C., and methanol was distilled off over 4.5 hours. Thereafter, 120 g of Solvesso 150 was added, the temperature was raised to 40 ° C., and sodium chloride in the reaction system was removed by filtration. The solution was further reacted at 175 ° C. for 2 hours, then cooled to room temperature and the precipitated product was isolated by filtration and washed with methanol to obtain 18.4 g (yield 61.4%) of a slightly yellow powder. .
[0019]
The obtained compound had a melting point of 298 ° C. and was confirmed to be the target product (2-hydroxy-4,6-diphenyl-s-triazine) by infrared absorption spectrum.
[0020]
The infrared absorption wavelengths (cm ⁻¹ ) were 3430, 2900, 1650, 1530, 1480, 1360, 990, and 710.
[0021]
(Example 2)
40 g (purity 94%, 0.24 mol) of benzamidine hydrochloride was dissolved in 40 g of methanol, and 46.3 g (0.24 mol) of 28% sodium methoxide methanol solution was added dropwise to this solution at room temperature. Thereafter, 103 g (0.48 mol) of diphenyl carbonate was added and reacted at room temperature for 7 hours. Further, the pressure was reduced at 40 ° C., and methanol was distilled off over 4.5 hours. Thereafter, 120 g of Solvesso 150 was added, the temperature was raised to 40 ° C., and sodium chloride in the reaction system was removed by filtration. The solution was further reacted at 175 ° C. for 2 hours, then cooled to room temperature and the precipitated product was isolated by filtration and washed with methanol to obtain 21.9 g of a slightly yellow powder (yield 73.3%). .
[0022]
The obtained compound had a melting point of 298 ° C., and the infrared absorption spectrum was the same as that of Example 1, so that it was confirmed to be the same target product.
[0023]
【The invention's effect】
According to the present invention, 2-hydroxy-4,6-diaryl-s-triazine can be produced without using a compound having problems in toxicity and corrosivity such as phosgene and chloroformate.

Claims (1)

Benzamidine compound represented by the following formula 1 or reacting a hydrogen halide salt and carbonate of the compound, a process for the preparation of 2-hydroxy-4,6-diaryl -s- triazine, is 該A reel represented by formula 2, wherein the benzalkonium method of 2-hydroxy-4,6-diaryl -s- triazine;

However, of the first and of in 2 _R 1, _{R 2,} and _{R 3} each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group, a halogen atom or a hydroxyl group.