JPH0733861A - Production of polyhydroxycarboxylic acid - Google Patents
Production of polyhydroxycarboxylic acidInfo
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- JPH0733861A JPH0733861A JP18109993A JP18109993A JPH0733861A JP H0733861 A JPH0733861 A JP H0733861A JP 18109993 A JP18109993 A JP 18109993A JP 18109993 A JP18109993 A JP 18109993A JP H0733861 A JPH0733861 A JP H0733861A
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- organic solvent
- reaction
- reaction mixture
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- solvent
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、医療用材料や汎用樹脂
代替の生分解性ポリマーとして有用なポリヒドロキシカ
ルボン酸を、ヒドロキシカルボン酸から直接脱水縮合に
より製造する方法に関する。ヒドロキシカルボン酸の中
でも、特に乳酸は、自然界に広く分布し動植物及び人畜
に対して無害であり、その重合物であるポリ乳酸は、水
の存在下で比較的容易に加水分解を受け、また、生体内
でも加水分解され吸収されるところから上記用途に用い
得るポリマーとして注目されている。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyhydroxycarboxylic acid useful as a biodegradable polymer as an alternative to medical materials and general-purpose resins by direct dehydration condensation from hydroxycarboxylic acid. Among hydroxycarboxylic acids, especially lactic acid is widely distributed in nature and is harmless to animals and plants and humans and animals, and polylactic acid as a polymer thereof is relatively easily hydrolyzed in the presence of water, and Since it is hydrolyzed and absorbed even in the living body, it is attracting attention as a polymer that can be used for the above-mentioned applications.
【０００２】[0002]
【従来技術】ＷＯ９３／１２１６０には、ヒドロキシカ
ルボン酸類またはそのオリゴマーを、有機溶媒中実質的
に水の非存在下に縮合することを特徴とするポリヒドロ
キシカルボン酸の製造方法が記載示されている。そして
その製造方法において種々の触媒が記載されていて、錫
および錫化合物が使用できることが記載されているが、
高分子量のポリヒドロキシカルボン酸を得るためには長
い反応時間を必要としている。しかしながら、それらの
錫化合物の酸化状態を２価に保ちながら反応することに
より、触媒活性を維持し、反応速度を高めることができ
るとの記載はない。2. Description of the Related Art WO93 / 12160 describes a method for producing a polyhydroxycarboxylic acid, which comprises condensing a hydroxycarboxylic acid or an oligomer thereof in an organic solvent in the substantial absence of water. . And various catalysts are described in the production method, and it is described that tin and tin compounds can be used.
Long reaction times are required to obtain high molecular weight polyhydroxycarboxylic acids. However, there is no description that the catalytic activity can be maintained and the reaction rate can be increased by reacting while maintaining the oxidation state of these tin compounds as divalent.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、ヒドロキシ
カルボン酸類の直接脱水縮合により、上記従来技術の欠
点を克服して、反応速度を高め、短い反応時間で高い分
子量のポリヒドロキシカルボン酸類を得る製造方法を提
供することを課題とする。DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art by direct dehydration condensation of hydroxycarboxylic acids to increase the reaction rate and obtain polyhydroxycarboxylic acids of high molecular weight in a short reaction time. It is an object to provide a manufacturing method.
【０００４】[0004]
【課題を解決するための手段】本発明者らは、ヒドロキ
シカルボン酸類またはそのオリゴマーを、有機溶媒中実
質的に水の不存在下に縮合することを特徴とするポリヒ
ドロキシカルボン酸の製造方法が本発明は、ヒドロキシ
カルボン酸の直接脱水縮合反応により、ポリヒドロキシ
カルボン酸およびそれらを製造する方法において、触媒
として錫の化合物を用いたとき、錫の酸化状態を２価に
保ちながら反応すれば、反応速度を高め、短い反応時間
で高い分子量のポリヒドロキシカルボン酸類を得ること
を見いだし、本発明を完成した。The present inventors have proposed a method for producing a polyhydroxycarboxylic acid, which comprises condensing a hydroxycarboxylic acid or an oligomer thereof in an organic solvent in the substantial absence of water. The present invention is a polyhydroxycarboxylic acid and a method for producing them by direct dehydration condensation reaction of a hydroxycarboxylic acid. When a tin compound is used as a catalyst, the reaction can be carried out while keeping the tin oxidation state divalent. The present invention has been completed by increasing the reaction rate and obtaining high molecular weight polyhydroxycarboxylic acids in a short reaction time.
【０００５】すなわち、本発明は、実質的に水の不存在
下で、ヒドロキシカルボン酸類またはそのオリゴマー
を、有機溶媒を含む反応混合物中で脱水縮合反応し、重
量平均分子量が約１５，０００以上であるポリヒドロキ
シカルボン酸の製造方法において、錫触媒を使用し、反
応中の錫の酸化状態を２価に保ちながら行うことを特徴
とするポリヒドロキシカルボン酸の製造方法。ヒドロキ
シカルボン酸類またはそのオリゴマーを、有機溶媒中、
実質的に水の非存在下に縮合することを特徴とするポリ
ヒドロキシカルボン酸の製造方法および該製造方法で製
造したポリヒドロキシカルボン酸である。That is, according to the present invention, a hydroxycarboxylic acid or an oligomer thereof is subjected to dehydration condensation reaction in a reaction mixture containing an organic solvent in the substantial absence of water to give a weight average molecular weight of about 15,000 or more. A method for producing a polyhydroxycarboxylic acid, which comprises using a tin catalyst and maintaining the oxidation state of tin during the reaction to be divalent. Hydroxycarboxylic acid or its oligomer in an organic solvent,
It is a method for producing a polyhydroxycarboxylic acid, which is characterized in that it is condensed substantially in the absence of water, and a polyhydroxycarboxylic acid produced by the method.
【０００６】脱水縮合反応において錫の酸化状態を２価
に保ちながら行うためには、反応系内に酸素がないこと
が望ましい。そのためには、１）原料のヒドロキシカル
ボン酸類および溶媒を脱気するかまたは不活性ガスによ
るバブリングし、２）原料等の反応機への装入を不活性
ガス雰囲気下で行い、３）反応中は、反応系内を不活性
雰囲気に保つ必要がある。In order to carry out the dehydration condensation reaction while keeping the tin oxidation state divalent, it is desirable that the reaction system be free of oxygen. For that purpose, 1) degassing the raw material hydroxycarboxylic acids and solvent or bubbling with an inert gas, 2) charging the raw material into the reactor under an inert gas atmosphere, and 3) during the reaction. Must maintain an inert atmosphere in the reaction system.
【０００７】特に脱水反応の初期のように反応マスの含
水率が高い状態、例えば０．１ｗｔ％以上では、２価の
錫が酸化され易いため、不活性ガス雰囲気下で行う等、
空気との接触をさけて反応を行う等の手段を用いること
が好ましい。Particularly in a state where the water content of the reaction mass is high as in the initial stage of the dehydration reaction, for example, 0.1 wt% or more, divalent tin is easily oxidized, so that the reaction is performed in an inert gas atmosphere.
It is preferable to use a means such that the reaction is avoided by avoiding contact with air.
【０００８】本発明の製造方法に使用できる有機溶媒
は、例えば、トルエン、キシレン、メシチレン等の炭化
水素系溶媒、クロロベンゼン、ブロモベンゼン、ヨ−ド
ベンゼン、ジクロロベンゼン、１，１，２，２−テトラ
クロロエタン、p-クロロトルエン等のハロゲン系溶媒、
３−ヘキサノン、アセトフェノン、ベンゾフェノン等の
ケトン系溶媒、ジブチルエ−テル、アニソ−ル、フェネ
トール、ｏ−ジメトキシベンゼン、ｐ−ジメトキシベン
ゼン、３−メトキシトルエン、ジベンジルエーテル、ベ
ンジルフェニルエーテル、メトキシナフタレン等のエー
テル系溶媒、フェニルスルフィド、チオアニソール等の
チオエーテル溶媒、安息香酸メチル、フタル酸メチル、
フタル酸エチル等のエステル系溶媒、ジフェニルエーテ
ル、または４−メチルフェニルエーテル、３−メチルフ
ェニルエーテル、３−フェノキシトルエン等のアルキル
置換ジフェニルエーテル、または、４−ブロモフェニル
エーテル、４−クロロフェニルエ−テル、４−ブロモジ
フェニルエーテル、４−メチル−４’−ブロモジフェニ
ルエーテル等のハロゲン置換ジフェニルエーテル、また
は、４−メトキシジフェニルエーテル、４−メトキシフ
ェニルエーテル、３−メトキシフェニルエーテル、４−
メチル−４’−メトキシジフェニルエーテル等のアルコ
キシ置換ジフェニルエーテル、または、ジベンゾフラ
ン、キサンテン等の環状ジフェニルエーテル等のジフェ
ニルエーテル系溶媒が挙げられ、これらは、混合して用
いてもよい。そして、溶媒として容易に水と分液分離で
きるものが好ましく、特に平均分子量の高いポリヒドロ
キシカルボン酸を得るためにはエーテル系溶媒、アルキ
ル−アリールエーテル系溶媒およびジフェニルエーテル
系溶媒がより好ましいが、アルキル−アリールエーテル
系溶媒およびジフェニルエ−テル系溶媒が特に好まし
い。The organic solvent which can be used in the production method of the present invention is, for example, a hydrocarbon solvent such as toluene, xylene, mesitylene, chlorobenzene, bromobenzene, iodobenzene, dichlorobenzene, 1,1,2,2-tetrahydrofuran. Chlorethane, halogen-based solvents such as p-chlorotoluene,
Ketone solvents such as 3-hexanone, acetophenone and benzophenone, dibutyl ether, anisole, phenetole, o-dimethoxybenzene, p-dimethoxybenzene, 3-methoxytoluene, dibenzyl ether, benzylphenyl ether, methoxynaphthalene, etc. Ether solvents, phenyl ether, thioether solvents such as thioanisole, methyl benzoate, methyl phthalate,
Ester solvent such as ethyl phthalate, diphenyl ether, or alkyl-substituted diphenyl ether such as 4-methylphenyl ether, 3-methylphenyl ether, 3-phenoxytoluene, or 4-bromophenyl ether, 4-chlorophenyl ether, 4 -Halogen-substituted diphenyl ether such as -bromodiphenyl ether, 4-methyl-4'-bromodiphenyl ether, or 4-methoxydiphenyl ether, 4-methoxyphenyl ether, 3-methoxyphenyl ether, 4-
Examples thereof include alkoxy-substituted diphenyl ethers such as methyl-4′-methoxydiphenyl ether and diphenyl ether solvents such as cyclic diphenyl ethers such as dibenzofuran and xanthene, and these may be used as a mixture. And, as the solvent, those which can be easily separated from water by separation are preferable, and particularly ether type solvents, alkyl-aryl ether type solvents and diphenyl ether type solvents are more preferable in order to obtain a polyhydroxycarboxylic acid having a high average molecular weight. -Aryl ether solvents and diphenyl ether solvents are particularly preferred.
【０００９】本発明の溶剤の沸点は高い方が良く、好ま
しくは１８０℃以上の沸点を持つ溶媒を用い、低温、高
真空度で反応を行うことにより、好ましくない副反応を
ともなわず効率的に脱水を進めることができる。The solvent of the present invention preferably has a high boiling point, preferably by using a solvent having a boiling point of 180 ° C. or higher, and by carrying out the reaction at a low temperature and a high degree of vacuum, the reaction can be carried out efficiently without undesired side reactions. Dehydration can proceed.
【００１０】これらの溶媒の使用量は得られるポリマー
の濃度で１０〜８０％であることが好ましい。The amount of these solvents used is preferably 10 to 80% in terms of the concentration of the polymer obtained.
【００１１】本発明の製造方法において、生成した水を
反応系外に流出させるには、用いた有機溶媒と水との共
沸によることが好ましい。共沸により流出した有機溶媒
は、含有する水の量が該有機溶媒に対する水の溶解度よ
り多い場合は分液により水を除去した後、反応系内に戻
して良く、さらに用いた有機溶媒に溶解した水を除くた
めに、乾燥剤で処理したり、蒸留等により水分量を低下
させた後、反応系に戻しても良い。また共沸により流出
した有機溶媒の代わりに、新たな水分量の低い有機溶媒
を装入しても良い。また反応の始めの部分で水分を減圧
により除去し、反応混合物の水分を所定の値とすること
もできる。In the production method of the present invention, it is preferable that the produced water is allowed to flow out of the reaction system by azeotropic distillation of the used organic solvent and water. When the amount of water contained is greater than the solubility of water in the organic solvent, the azeotropically discharged organic solvent may be returned to the reaction system after removing the water by liquid separation, and further dissolved in the used organic solvent. In order to remove the above-mentioned water, it may be returned to the reaction system after treatment with a desiccant or after reducing the water content by distillation or the like. Further, a new organic solvent having a low water content may be charged in place of the organic solvent that has flown out by azeotropic distillation. Further, the water content of the reaction mixture can be adjusted to a predetermined value by removing the water content at the beginning of the reaction by reducing the pressure.
【００１２】ポリヒドロキシカルボン酸の平均分子量
は、反応系に装入する有機溶媒の水分量にも依存し、溶
媒の種類にもよるが、溶媒が４００〜５００ｐｐｍと高
い水分量を有する場合、得られるポリヒドロキシカルボ
ン酸の平均分子量は、１５，０００〜５０，０００であ
る。しかしながら、上記高水分量でもジフェニルエーテ
ル系溶媒を用いると４０，０００〜５０，０００の平均
分子量のポリヒドロキシカルボン酸が得られることは驚
くべきことである。更に高い平均分子量のポリヒドロキ
シカルボン酸を得るためには、反応系に装入する有機溶
媒の水分量が低いことが望ましく、共沸により流出した
有機溶媒を乾燥剤で処理して水を除去または減少して反
応系に戻すか、水分量の低い新たな有機溶媒を装入する
ことにより、挿入する水分量を５０ｐｐｍ以下とするこ
とにより、平均分子量Ｍｗ５０，０００〜２００，００
０のポリヒドロキシカルボン酸を得ることができる。The average molecular weight of the polyhydroxycarboxylic acid depends on the water content of the organic solvent charged into the reaction system and depends on the kind of the solvent, but it is obtained when the solvent has a high water content of 400 to 500 ppm. The average molecular weight of the obtained polyhydroxycarboxylic acid is 15,000 to 50,000. However, it is surprising that a polyhydroxycarboxylic acid having an average molecular weight of 40,000 to 50,000 can be obtained by using a diphenyl ether solvent even with the above high water content. In order to obtain a polyhydroxycarboxylic acid having a higher average molecular weight, it is desirable that the organic solvent charged to the reaction system has a low water content, and the organic solvent discharged by azeotropic treatment is treated with a desiccant to remove water or The average molecular weight Mw is from 50,000 to 200,000 by decreasing the amount of water to be inserted into the reaction system by reducing or returning to the reaction system or introducing a new organic solvent having a low water content to 50 ppm or less.
It is possible to obtain 0 polyhydroxycarboxylic acid.
【００１３】本発明の製造方法において、平均分子量の
高いポリヒドロキシカルボン酸を得るために用いる乾燥
剤としては、モレキュラーシーブ３Ａ、モレキュラーシ
ーブ４Ａ、モレキュラーシーブ５Ａ、モレキュラーシー
ブ１３Ｘ等のモレキュラーシーブ類、アルミナ、シリカ
ゲル、塩化カルシウム、硫酸カルシウム、五酸化二リ
ン、濃硫酸、過塩素酸マグネシウム、酸化バリウム、酸
化カルシウム、水酸化カリウム、水酸化ナトリウム、あ
るいは水素化カルシウム、水素化ナトリウム、水素化リ
チウムアルミニウム等の金属水素化物、または、ナトリ
ウム等のアルカリ金属等があげられる。中でも、取扱い
及び再生の容易さからモレキュラーシーブ類が好まし
い。In the production method of the present invention, as the desiccant used to obtain the polyhydroxycarboxylic acid having a high average molecular weight, molecular sieves such as molecular sieve 3A, molecular sieve 4A, molecular sieve 5A, and molecular sieve 13X, and alumina are used. , Silica gel, calcium chloride, calcium sulfate, phosphorus pentoxide, concentrated sulfuric acid, magnesium perchlorate, barium oxide, calcium oxide, potassium hydroxide, sodium hydroxide, or calcium hydride, sodium hydride, lithium aluminum hydride, etc. Examples of the metal hydrides, alkali metals such as sodium, and the like. Among them, molecular sieves are preferable because they are easy to handle and regenerate.
【００１４】本発明の製造方法における反応温度は、ポ
リマーの生成速度および生成したポリマーの熱分解速度
を考慮して、好ましくは８０〜２００℃であり、より好
ましくは、１１０〜１７０℃である。縮合反応は、通
常、常圧下に使用する有機溶媒の流出温度で行われる。
反応温度を好ましい範囲にするために高沸点の有機溶媒
を用いる場合には、減圧下で行っても良いし、低沸点の
有機溶媒を用いる場合には、加圧下で行っても良い。The reaction temperature in the production method of the present invention is preferably 80 to 200 ° C., more preferably 110 to 170 ° C., in consideration of the production rate of the polymer and the thermal decomposition rate of the produced polymer. The condensation reaction is usually carried out at the outflow temperature of the organic solvent used under normal pressure.
When a high-boiling organic solvent is used to keep the reaction temperature in a preferable range, it may be carried out under reduced pressure, and when a low-boiling organic solvent is used, it may be carried out under pressure.
【００１５】本発明に使用するヒドロキシカルボン酸
は、分子内にヒドロキシ基を有する脂肪族カルボン酸類
であり、例えば、乳酸、グリコール酸、３−ヒドロキシ
ブチリックアシッド、４−ヒドロキシブチリックアシッ
ド、３−ヒドロキシバレリックアシッド、５−ヒドロキ
シバレリックアシッド、６−ヒドロキシカプロン酸等が
挙げられる。The hydroxycarboxylic acid used in the present invention is an aliphatic carboxylic acid having a hydroxy group in the molecule, and examples thereof include lactic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid and 3-hydroxybutyric acid. Examples thereof include hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid and the like.
【００１６】分子内に不斉炭素を有する場合はＤ体、Ｌ
体、それぞれ単独であっても良いし、Ｄ体とＬ体の混合
物すなわちラセミ体であってもよい。When the molecule has an asymmetric carbon, D-form, L-form
Each of the isomers may be alone, or a mixture of the D isomer and the L isomer, that is, a racemic isomer.
【００１７】また、例えば乳酸とグリコール酸とを混合
使用してコポリマーを製造するように、一つのヒドロキ
シカルボン酸に他のヒドロキシカルボン酸を混合しても
良い。Further, for example, one hydroxycarboxylic acid may be mixed with another hydroxycarboxylic acid so that a copolymer is produced by mixing lactic acid and glycolic acid.
【００１８】本発明の製造方法において使用する錫触媒
としては、２価の錫化合物が挙げられ、例えば、酸化第
一錫、フッ化第一錫、塩化第一錫、臭化第一錫、沃化第
一錫、硫酸第一錫、リン酸第一錫等の無機錫化合物、酢
酸第一錫、プロピオン酸第一錫、２−エチルヘキサン酸
第一錫等の有機カルボン酸錫、トリフルオロメタンスル
ホン酸第一錫等の有機スルホン酸錫が挙げられ、好まし
くは酸化第一錫、フッ化第一錫、塩化第一錫、臭化第一
錫、沃化第一錫の無機錫化合物、酢酸第一錫、プロピオ
ン酸第一錫、２−エチルヘキサン酸第一錫等の有機カル
ボン酸錫が挙げられる。Examples of the tin catalyst used in the production method of the present invention include divalent tin compounds. Examples thereof include stannous oxide, stannous fluoride, stannous chloride, stannous bromide and iodine. Inorganic tin compounds such as stannous oxide, stannous sulfate and stannous phosphate, stannous acetate, stannous propionate, stannous 2-ethylhexanoate and other organic carboxylates, trifluoromethanesulfone Examples thereof include organic tin sulfonates such as stannous acid, preferably stannous oxide, stannous fluoride, stannous chloride, stannous bromide, inorganic tin compounds of stannous iodide, and stannous acetate. Organic tin salts such as stannous tin, stannous propionate, and stannous 2-ethylhexanoate can be used.
【００１９】その使用量は、使用するヒドロキシカルボ
ン酸、または、それらのオリゴマーの０．０００１〜１
０重量％が良く、経済性を考えると、０．００１〜２重
量％が好ましい。The amount used is 0.0001 to 1 of the hydroxycarboxylic acid or oligomer thereof used.
0 wt% is preferable, and 0.001 to 2 wt% is preferable in consideration of economy.
【００２０】触媒の使用量が使用するヒドロキシカルボ
ン酸、または、それらのオリゴマーの０．０００１重量
％未満の場合は触媒使用の効果がなく、高分子量のポリ
マーが得られない。また、酸化第二錫、塩化第二錫、酢
酸第二錫等の４価の錫化合物を触媒として使用した場合
も、４価の錫化合物は触媒活性が低い。When the amount of the catalyst used is less than 0.0001% by weight of the hydroxycarboxylic acid or the oligomer thereof, the effect of using the catalyst is not obtained and a high molecular weight polymer cannot be obtained. Also, when a tetravalent tin compound such as stannic oxide, stannic chloride, stannic acetate is used as a catalyst, the tetravalent tin compound has low catalytic activity.
【００２１】本発明の縮合反応は、連続操作でも回分操
作でも行うことができる。また溶媒の脱水、溶媒の装入
も連続操作でも回分操作でも行うことができる。The condensation reaction of the present invention can be carried out either continuously or batchwise. Dehydration of the solvent and charging of the solvent can also be carried out by continuous operation or batch operation.
【００２２】本発明の方法で得られた高分子量のポリヒ
ドロキシカルボン酸類は、延伸、ブロー、真空成形等の
二次加工を行うことができる。従って、本発明の方法に
より得られる、高分子量のポリヒドロキシカルボン酸類
は、医療用材料としてあるいは、発泡体、網状体等の従
来の汎用樹脂の代替物として使用することができる。The high molecular weight polyhydroxycarboxylic acids obtained by the method of the present invention can be subjected to secondary processing such as stretching, blowing and vacuum forming. Therefore, the high molecular weight polyhydroxycarboxylic acids obtained by the method of the present invention can be used as a medical material or as a substitute for conventional general-purpose resins such as foams and nets.
【００２３】[0023]
【実施例】以下に実施例を示すが、本発明はこれに限定
されるものではない。なお、本明細書記載のポリマーの
平均分子量（Ｍｗ）は、ゲルパーミエーションクロマト
グラフィー（カラム温度４０℃、クロロホルム溶媒）に
より、ポリスチレン標準サンプルとの比較で求めた。EXAMPLES Examples will be shown below, but the present invention is not limited thereto. The average molecular weight (Mw) of the polymer described in the present specification was determined by gel permeation chromatography (column temperature 40 ° C, chloroform solvent) in comparison with a polystyrene standard sample.
【００２４】実施例１ Ｄｅａｎ Ｓｔａｒｋ ｔｒａｐを備えた装置を用い、
あらかじめ脱気処理をした９０％Ｌ−乳酸３６．０ｇ、
ジフェニルエーテル７５．６ｇ、触媒として塩化第一錫
（二水和物）０．３１ｇを窒素ガス雰囲気下に装入した
後、系内を１００ｍｍＨｇに減圧し１時間かけて室温か
ら１３０℃に昇温し、続いて１３０℃／５０ｍｍＨｇで
３時間、１３０℃／３０ｍｍＨｇで３時間、系外に水を
流出しながら加熱撹拌した。次に１４０℃／２３ｍｍＨ
ｇで８時間、共沸脱水を行いジフェニルエーテルと共沸
する水分を除去した。共沸脱水後、反応マス中の全錫及
び２価の錫をそれぞれキレート滴定、沃素滴定により分
析したところ、反応マス中の全錫濃度は１６００ｐｐ
ｍ、２価の錫濃度は１５７０ｐｐｍであった。その後、
Dean Stark trap をはずし、モレキュラーシーブ３Ａ、
２０ｇが充填された管を取り付け、還流により流出する
溶媒がモレキュラーシーブを通って再び系内に戻るよう
にした。１３０℃／１５ｍｍＨｇで３０時間反応を行
い、平均分子量Ｍｗ：１７０，０００のポリ乳酸を得
た。この反応溶液にクロロホルム１７０ｇを加えた後、
メタノール６００ｍｌ中に排出し、析出した結晶を吸引
濾過し、続いて、メタノール洗浄、ヘキサン洗浄を行っ
た。３０℃／５ｍｍＨｇで減圧乾燥後、ポリ乳酸２１．
５ｇ（収率８３％）を得た。Example 1 Using an apparatus equipped with a Dean Stark trap,
36.0 g of 90% L-lactic acid that has been degassed in advance,
After charging 75.6 g of diphenyl ether and 0.31 g of stannous chloride (dihydrate) as a catalyst under a nitrogen gas atmosphere, the pressure inside the system was reduced to 100 mmHg, and the temperature was raised from room temperature to 130 ° C over 1 hour. Subsequently, the mixture was heated and stirred at 130 ° C./50 mmHg for 3 hours and at 130 ° C./30 mmHg for 3 hours while flowing water out of the system. Next 140 ° C / 23mmH
Azeotropic dehydration was carried out at 8 g for 8 hours to remove water azeotropically distilled with diphenyl ether. After azeotropic dehydration, total tin and divalent tin in the reaction mass were analyzed by chelate titration and iodine titration, respectively, and the total tin concentration in the reaction mass was 1600 pp.
The m-divalent tin concentration was 1570 ppm. afterwards,
Dean Stark trap is removed, molecular sieve 3A,
A tube filled with 20 g was attached so that the solvent flowing out by reflux was returned to the system through the molecular sieve. The reaction was carried out at 130 ° C./15 mmHg for 30 hours to obtain polylactic acid having an average molecular weight Mw: 170,000. After adding 170 g of chloroform to this reaction solution,
The crystals were discharged into 600 ml of methanol, and the precipitated crystals were suction-filtered, followed by washing with methanol and hexane. After drying under reduced pressure at 30 ° C./5 mmHg, polylactic acid 21.
5 g (yield 83%) was obtained.
【００２５】実施例２ 触媒として酸化第一錫０．１８ｇを使用する以外は実施
例１と同様に反応を行ない、平均分子量１３５，０００
のポリ乳酸２１．０ｇ（収率８１％）を得た。また実施
例１と同様に、共沸脱水後、反応マス中の全錫及び２価
の錫分析を行ったところ、反応マス中の全錫濃度は１６
４０ｐｐｍ、２価の錫濃度は１６００ｐｐｍであった。Example 2 The reaction was carried out in the same manner as in Example 1 except that 0.18 g of stannous oxide was used as a catalyst, and the average molecular weight was 135,000.
21.0 g of polylactic acid (yield 81%) was obtained. Further, as in Example 1, after azeotropic dehydration, total tin and divalent tin in the reaction mass were analyzed. As a result, the total tin concentration in the reaction mass was 16
The concentration of divalent tin at 40 ppm was 1600 ppm.
【００２６】実施例３ 触媒として酢酸第一錫０．３２ｇを使用する以外は実施
例１と同様に反応を行ない、平均分子量１４０，０００
のポリ乳酸２１．７ｇ（収率８４％）を得た。また実施
例１と同様に、共沸脱水後、反応マス中の全錫及び２価
の錫分析を行ったところ、反応マス中の全錫濃度は１５
８０ｐｐｍ，２価の錫濃度は１５６０ｐｐｍであった。Example 3 The reaction was carried out in the same manner as in Example 1 except that 0.32 g of stannous acetate was used as a catalyst, and the average molecular weight was 140,000.
21.7 g (yield 84%) of polylactic acid was obtained. Further, in the same manner as in Example 1, after azeotropic dehydration, total tin and divalent tin in the reaction mass were analyzed. The total tin concentration in the reaction mass was 15
The concentration of divalent tin at 80 ppm was 1560 ppm.
【００２７】実施例４ 触媒として２−エチルヘキサン酸第一錫（錫含有率２８
％）０．５８ｇを使用する以外は実施例１と同様に反応
を行ない、平均分子量１２０，０００のポリ乳酸２０．
５ｇ（収率７９％）を得た。また実施例１と同様に共沸
脱水後、反応マス中の全錫及び２価の錫分析を行ったと
ころ、反応マス中の全錫濃度は１６５０ｐｐｍ、２価の
錫濃度は１６３０ｐｐｍであった。Example 4 Stannous 2-ethylhexanoate (tin content 28
%) Polylactic acid having an average molecular weight of 120,000 was reacted in the same manner as in Example 1 except that 0.58 g of polylactic acid 20.
5 g (yield 79%) was obtained. After azeotropic dehydration in the same manner as in Example 1, analysis of total tin and divalent tin in the reaction mass revealed that the total tin concentration in the reaction mass was 1650 ppm and the divalent tin concentration was 1630 ppm.
【００２８】比較例 原料の９０％Ｌ−乳酸の脱気処理をせず、原料の装入を
窒素雰囲気下に行わず、空気雰囲気下で行う他は実施例
１と同様に反応を行った。共沸脱水後、反応マス中の全
錫及び２価の錫分析を行ったところ、反応マス中の全錫
濃度は１５８０ｐｐｍ、２価の錫は５２０ｐｐｍに減少
していた。その後、実施例１と同様にＤｅａｎ Ｓｔａ
ｒｋ ｔｒａｐをはずし、モレキュラーシーブ３Ａ、２
０ｇが充填された管を取り付け、還流により流出する溶
媒がモレキュラーシーブを通って再び系内に戻るように
した。１３０℃／１５ｍｍＨｇで３０時間反応した時の
ポリ乳酸の平均分子量は、９０，０００で実施例１の場
合と比較して重合速度が遅くなった。さらに３０時間反
応を続け、平均分子量１７０，０００のポリ乳酸を得
た。Comparative Example A reaction was carried out in the same manner as in Example 1 except that 90% L-lactic acid as a raw material was not degassed and the raw material was not charged in a nitrogen atmosphere but in an air atmosphere. After azeotropic dehydration, analysis of total tin and divalent tin in the reaction mass revealed that the total tin concentration in the reaction mass was reduced to 1580 ppm and divalent tin was decreased to 520 ppm. Then, as in Example 1, Dean Sta.
Remove rk trap, molecular sieve 3A, 2
A tube filled with 0 g was attached so that the solvent flowing out by reflux was returned to the system through the molecular sieve. The average molecular weight of polylactic acid after reacting at 130 ° C./15 mmHg for 30 hours was 90,000, and the polymerization rate was slower than in the case of Example 1. The reaction was continued for further 30 hours to obtain polylactic acid having an average molecular weight of 170,000.
【００２９】[0029]
【発明の効果】本発明により、生分解性ポリマーとして
有用なポリヒドロキシカルボン酸をヒドロキシカルボン
酸からの直接脱水縮合により短い反応時間で得ることが
できる。また、本発明の方法によれば、フィルムや糸等
の成形物にして充分な強度を持ったポリヒドロキシカル
ボン酸類を容易に得ることができる。INDUSTRIAL APPLICABILITY According to the present invention, polyhydroxycarboxylic acid useful as a biodegradable polymer can be obtained in a short reaction time by direct dehydration condensation from hydroxycarboxylic acid. Further, according to the method of the present invention, a polyhydroxycarboxylic acid having sufficient strength can be easily obtained as a molded product such as a film or a thread.
Claims (13)
ルボン酸類またはそのオリゴマーを、有機溶媒を含む反
応混合物中で脱水縮合反応し、重量平均分子量が約１
５，０００以上であるポリヒドロキシカルボン酸の製造
方法において、錫触媒を使用し、反応中の錫の酸化状態
を２価に保ちながら行うことを特徴とするポリヒドロキ
シカルボン酸の製造方法。1. A hydroxycarboxylic acid or an oligomer thereof is subjected to a dehydration condensation reaction in a reaction mixture containing an organic solvent in the substantial absence of water to give a weight average molecular weight of about 1.
A method for producing a polyhydroxycarboxylic acid having a molecular weight of 5,000 or more, wherein a tin catalyst is used and the oxidation state of tin during the reaction is maintained to be divalent.
徴とする、請求項１記載の製造方法。2. The manufacturing method according to claim 1, wherein the reaction is performed in an inert gas atmosphere.
部を除去し、除去される有機溶媒の水分量よりも少ない
か等しい水分量を持った追加有機溶媒を反応混合物に装
入することを特徴とする、請求項１記載の製造方法。3. At least a part of the organic solvent is removed from the reaction mixture, and an additional organic solvent having a water content less than or equal to the water content of the organic solvent to be removed is charged to the reaction mixture. The manufacturing method according to claim 1.
燥剤と接触せしめて水分を除去した後、追加溶媒として
反応混合物に戻すことを特徴とする、請求項３記載の製
造方法。4. The production method according to claim 3, wherein the organic solvent removed from the reaction mixture is brought into contact with a desiccant to remove water, and then returned to the reaction mixture as an additional solvent.
二リンまたは金属水素化物である請求項４記載の製造方
法。5. The method according to claim 4, wherein the desiccant is a molecular sieve, diphosphorus pentoxide or a metal hydride.
分量が５０ｐｐｍ以下である請求項３記載の製造方法。6. The production method according to claim 3, wherein the organic solvent additionally charged in the reaction mixture has a water content of 50 ppm or less.
去し、次に反応混合物から有機溶媒の一部が除去するこ
とを特徴とする、請求項３記載の製造方法。7. The method according to claim 3, wherein the reaction mixture is first azeotropically removed of water, and then a part of the organic solvent is removed from the reaction mixture.
１記載の製造方法。8. The method according to claim 1, wherein the organic solvent is an ether solvent.
フェネトールである請求項７記載の製造方法。9. The method according to claim 7, wherein the ether organic solvent is anisole or phenetole.
である請求項１記載の製造方法。10. The production method according to claim 1, wherein the organic solvent is a diphenyl ether solvent.
ルエーテルである請求項１０記載の製造方法。11. The method according to claim 10, wherein the diphenyl ether solvent is diphenyl ether.
請求項１記載の製造方法。12. The method according to claim 1, wherein the boiling point of the organic solvent is 180 ° C. or higher.
リヒドロキシカルボン酸。13. A polyhydroxycarboxylic acid obtained by the production method according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18109993A JP3347406B2 (en) | 1993-07-22 | 1993-07-22 | Method for producing polyhydroxycarboxylic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18109993A JP3347406B2 (en) | 1993-07-22 | 1993-07-22 | Method for producing polyhydroxycarboxylic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0733861A true JPH0733861A (en) | 1995-02-03 |
| JP3347406B2 JP3347406B2 (en) | 2002-11-20 |
Family
ID=16094824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18109993A Expired - Fee Related JP3347406B2 (en) | 1993-07-22 | 1993-07-22 | Method for producing polyhydroxycarboxylic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3347406B2 (en) |
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