JPH08119961A - Production of lactide - Google Patents
Production of lactideInfo
- Publication number
- JPH08119961A JPH08119961A JP6256528A JP25652894A JPH08119961A JP H08119961 A JPH08119961 A JP H08119961A JP 6256528 A JP6256528 A JP 6256528A JP 25652894 A JP25652894 A JP 25652894A JP H08119961 A JPH08119961 A JP H08119961A
- Authority
- JP
- Japan
- Prior art keywords
- lactic acid
- lactide
- crude
- reduced pressure
- under reduced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、乳酸ポリマーの減圧接
触熱分解によってラクチドを製造する方法に関するもの
であり、発酵法等で得られる粗乳酸の精製方法にも利用
可能なものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing lactide by catalytically decomposing a lactic acid polymer under reduced pressure, and is also applicable to a method for purifying crude lactic acid obtained by a fermentation method or the like.
【０００２】[0002]
【従来の技術】ラクチドの簡便な製造方法として乳酸を
減圧下、100 〜200 ℃で熱重縮合させて低分子量ポリマ
ーを得、この低分子量ポリマーの接触熱分解によってラ
クチドを製造する方法がある。この方法での要は熱分解
触媒であり、Sb2O3 やオクチル酸錫が最適な触媒として
利用されている。しかし、これら触媒はSbやSnの重金属
を含むため生体への害毒が強く、かつ価格的にも問題が
ある。毒性の少ない安価な触媒の探索、開発が望まれ
た。2. Description of the Related Art As a simple method for producing lactide, there is a method in which lactic acid is thermally polycondensed under reduced pressure at 100 to 200 ° C. to obtain a low molecular weight polymer, and lactide is produced by catalytic thermal decomposition of this low molecular weight polymer. The key to this method is a thermal decomposition catalyst, and Sb 2 O 3 and tin octylate are used as the optimum catalysts. However, since these catalysts contain heavy metals such as Sb and Sn, they are highly toxic to living organisms and have a problem in terms of cost. It was desired to search for and develop an inexpensive catalyst with low toxicity.
【０００３】一方、発酵乳酸の精製方法では、発酵液中
の不純物を除去した後、蒸発脱水濃縮して粗乳酸を得て
いるが、粗乳酸の不純物は活性炭等の吸着剤やイオン交
換樹脂の使用によって低減できるものの、完全な不純物
の除去が困難なので、硫酸等の触媒の存在下でアルコ−
ルと反応させてエステル化し、精密蒸留して高純度乳酸
エステルを得た後、高純度乳酸エステルを酸加水分解し
て高純度乳酸を製造するといった複雑な工程を経てい
る。より簡便で経済的な精製方法の確立が必要とされ
た。On the other hand, in the method for purifying fermented lactic acid, impurities in the fermentation liquor are removed, and then crude lactic acid is obtained by evaporating, dehydrating and concentrating. The impurities in the crude lactic acid are adsorbents such as activated carbon and ion exchange resins. Although it can be reduced by using it, it is difficult to completely remove impurities. Therefore, alcohol can be removed in the presence of a catalyst such as sulfuric acid.
It undergoes a complicated process in which a high-purity lactic acid ester is obtained by subjecting it to esterification by reacting with alcohol and precision distillation to obtain a high-purity lactic acid ester, and then hydrolyzing the high-purity lactic acid ester to produce high-purity lactic acid. It was necessary to establish a more convenient and economical purification method.
【０００４】[0004]
【発明が解決しようとする課題】本発明は、高純度ラク
チドの簡易かつ経済的な製造方法と粗乳酸の精製方法を
提供することを目的とする。An object of the present invention is to provide a simple and economical method for producing high-purity lactide and a method for purifying crude lactic acid.
【０００５】[0005]
【課題を解決するための手段】本発明は、以下の発明を
包含する。 （１）乳酸を減圧下加熱重縮合させて低分子量のポリ乳
酸とした後、酸化第一鉄を触媒として、減圧下接触熱分
解することにより留出するラクチドを得ることを特徴と
するラクチドの製造方法。 （２）乳酸が発酵工程で得られた粗乳酸を減圧蒸留して
脱水したものである前記（１）に記載の製造方法。The present invention includes the following inventions. (1) Lactide obtained by subjecting lactic acid to polycondensation under heating under reduced pressure to form low-molecular weight polylactic acid, and then catalytically decomposing under reduced pressure using ferrous oxide as a catalyst to obtain lactide to be distilled. Production method. (2) The production method according to (1) above, wherein the lactic acid is obtained by subjecting crude lactic acid obtained in the fermentation step to vacuum distillation and dehydration.
【０００６】（３）得られたラクチドを晶析法又は再結
晶化法により精製する前記（１）又は（２）に記載の製
造方法。 （４）粗乳酸を減圧下加熱重縮合させて低分子量のポリ
乳酸とした後、酸化第一鉄を触媒として、減圧下接触熱
分解することにより留出するラクチドを得、次いでこれ
を加水分解し、乳酸を得ることを特徴とする乳酸の精製
方法。(3) The production method according to (1) or (2) above, wherein the obtained lactide is purified by a crystallization method or a recrystallization method. (4) Crude lactic acid is subjected to polycondensation by heating under reduced pressure to give a low molecular weight polylactic acid, and then lactide to be distilled out by catalytic pyrolysis under reduced pressure is obtained using ferrous oxide as a catalyst, and then this is hydrolyzed. And a method for purifying lactic acid, which comprises obtaining lactic acid.
【０００７】本発明方法では、ポリマーの熱分解触媒は
不可欠であるが、これまで使用されていたSb2O3 やオク
チル酸錫は活性及びラクチドへの選択性が高く有効な触
媒であるが有害であり、かつ高価である。本発明者ら
は、Sb2O3 と同等の活性と選択性を持ち、害のほとんど
なく、より安価な酸化第一鉄（FeO ）触媒で目的を達成
できることを見出した。これにより、触媒を使い捨てで
き、ラクチドへの転化が実用規模で実施できるに至っ
た。In the method of the present invention, a thermal decomposition catalyst for polymers is indispensable, but Sb 2 O 3 and tin octylate which have been used so far are active and have high selectivity to lactide, but are harmful. And is expensive. The present inventors have found that a less expensive ferrous oxide (FeO 3) catalyst having the same activity and selectivity as Sb 2 O 3 with little harm can achieve the purpose. As a result, the catalyst can be disposed of and the conversion to lactide can be carried out on a practical scale.
【０００８】一方、本方法を粗乳酸の精製方法として活
用する観点からは、粗乳酸をエステル化した後、蒸留法
によって精製する代わりに、粗乳酸を直接熱重縮合して
ポリマー化したものの減圧熱分解蒸留によって揮発性の
ラクチドとして蒸留精製、あるいは再結晶法によって精
製することができるので、エステル化剤やエステル化触
媒が不要となる利点を有する。即ち、精製工程が簡略化
されるため、経済性の向上が期待できる。On the other hand, from the viewpoint of utilizing this method as a method for purifying crude lactic acid, instead of esterifying the crude lactic acid and then purifying it by the distillation method, the crude lactic acid is directly polymerized by thermal polycondensation to reduce the pressure. Since volatile lactide can be purified by distillation by thermal decomposition or purified by a recrystallization method, there is an advantage that an esterifying agent and an esterification catalyst are not required. That is, since the refining process is simplified, improvement in economic efficiency can be expected.
【０００９】ここで用いる粗乳酸としては、発酵工程等
からの蛋白や無機塩類を含む粗乳酸でよく、減圧蒸留し
て脱水したものが好ましい。例えば、発酵工程で得られ
た乳酸水溶液を60〜100 ℃で減圧蒸留して脱水すること
により、乳酸濃度70％以上の粗乳酸を得ることができ
る。このようにして得られた粗乳酸は、そのまま利用可
能である。The crude lactic acid used here may be crude lactic acid containing proteins and inorganic salts from the fermentation step or the like, and is preferably dehydrated by vacuum distillation. For example, crude lactic acid having a lactic acid concentration of 70% or more can be obtained by dehydrating the aqueous lactic acid solution obtained in the fermentation step under reduced pressure at 60 to 100 ° C. The crude lactic acid thus obtained can be used as it is.
【００１０】精製乳酸及び粗乳酸の重縮合について述べ
れば、加熱重縮合における圧力は、通常30mmHg以下、好
ましくは10mmHg以下であり、温度は通常100 〜200 ℃、
好ましくは100 〜180 ℃であり、反応時間は、通常５〜
20時間である。接触熱分解における圧力は、通常１〜30
mmHg、好ましくは１〜15mmHgであり、温度は、通常200
〜300 ℃、好ましくは230 〜300 ℃であり、反応時間
は、通常１〜３時間である。触媒としては、酸化第一鉄
(FeO) を使用し、使用量は、通常５重量％以下である。Regarding the polycondensation of purified lactic acid and crude lactic acid, the pressure in the heat polycondensation is usually 30 mmHg or less, preferably 10 mmHg or less, and the temperature is usually 100 to 200 ° C.
The temperature is preferably 100 to 180 ° C., and the reaction time is usually 5 to
20 hours. The pressure in catalytic pyrolysis is usually 1 to 30.
mmHg, preferably 1 to 15 mmHg, the temperature is usually 200
-300 ° C, preferably 230-300 ° C, and the reaction time is usually 1-3 hours. As a catalyst, ferrous oxide
(FeO) is used, and the amount used is usually 5% by weight or less.
【００１１】以下に、加熱重縮合工程の好ましい態様を
示す。精製乳酸や粗乳酸を減圧下、60〜100 ℃に加熱し
て、水や揮発性不純物を蒸発除去して濃縮乳酸を得る。
更に、減圧下、温度を100 〜200 ℃まで段階的に上昇さ
せ、５〜20時間反応させて乳酸を重縮合させることによ
り、乳酸の低分子量ポリマー（重量平均分子量2,000 〜
20,000）を得る。発酵工程等からの粗乳酸には栄養源と
して加えた無機塩類や蛋白等が含まれるので、生成ポリ
マーの純度は高くないが、用途、例えば肥料のカプセル
化剤、苗鉢等、によってはそのまま製品として利用可能
である。The preferred embodiments of the heat polycondensation step are shown below. Purified lactic acid or crude lactic acid is heated under reduced pressure at 60 to 100 ° C. to evaporate and remove water and volatile impurities to obtain concentrated lactic acid.
Furthermore, under reduced pressure, the temperature is raised stepwise to 100 to 200 ° C., and the reaction is carried out for 5 to 20 hours to cause polycondensation of lactic acid, whereby a low molecular weight polymer of lactic acid (weight average molecular weight of 2,000 to
20,000). Crude lactic acid from the fermentation process, etc. contains inorganic salts and proteins added as nutrient sources, so the purity of the produced polymer is not high, but depending on the application, such as fertilizer encapsulating agent, nursery, etc. Is available as.
【００１２】以下に、熱分解蒸留工程の好ましい態様を
示す。加熱重縮合工程からのポリ乳酸又は粗ポリ乳酸を
減圧熱分解反応釜に移し、１〜30mmHgの減圧下、触媒と
して酸化第一鉄(FeO) を５重量％以下の量で添加し、20
0 〜300 ℃の温度でポリマーを熱分解してラクチド留分
を得る。熱分解して蒸気状で留出してくるラクチドを蒸
留塔に通して分縮し、精製ラクチドを回収することもで
きる。熱分解蒸留工程からのラクチド留分の純度は高い
が、更に、晶析法、有機溶剤を用いた再結晶化法によっ
て精製することにより、光学的にも純度の高いラクチド
を得ることができる。The preferred embodiment of the pyrolysis distillation step is shown below. Transfer the polylactic acid or crude polylactic acid from the heating polycondensation step to a vacuum pyrolysis reactor and add ferrous oxide (FeO) as a catalyst in an amount of 5% by weight or less under a reduced pressure of 1 to 30 mmHg.
The polymer is pyrolyzed at a temperature of 0 to 300 ° C. to obtain a lactide fraction. It is also possible to recover the purified lactide by subjecting the lactide, which is thermally decomposed and distilled in the form of vapor, to a distillation column for partial condensation. Although the lactide fraction from the pyrolysis distillation step has a high purity, lactide having a high optical purity can be obtained by further purifying it by a crystallization method or a recrystallization method using an organic solvent.
【００１３】ラクチドは、高分子量ポリ乳酸や共重合
体、又は他の合成原料として、利用価値が高い。また、
ラクチドは簡単に加水分解して、乳酸に転化する。高純
度ラクチドから高純度乳酸を得ることができる。発酵法
では使用する菌の選択によって、L-、D-、DL- 体を、合
成法ではDL- 体の光学異性乳酸が製造されるが、原料と
してこの光学異性乳酸の選択によって、L-、D-、DL- 、
meso- ラクチドの製造が可能である。Lactide has a high utility value as a high molecular weight polylactic acid, a copolymer, or other synthetic raw material. Also,
Lactide is easily hydrolyzed and converted to lactic acid. High-purity lactic acid can be obtained from high-purity lactide. In the fermentation method, L-, D-, and DL- isomers are produced by selecting the bacterium to be used, and in the synthetic method, DL- isomer of optically isomeric lactic acid is produced. D-, DL-,
It is possible to manufacture meso-lactide.
【００１４】[0014]
【実施例】以下、実施例により本発明を更に具体的に説
明するが、本発明の範囲は以下の実施例に限定されるも
のではない。 （実施例１）ポリ乳酸の製造 市販L-乳酸（和光純薬特級品(90%) ）、可溶性澱粉の乳
酸発酵液を電気透析法により分離濃縮した粗L-乳酸を試
料として、ポリ乳酸の合成を試みた。The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples. (Example 1) Production of polylactic acid Commercially available L-lactic acid (Wako Pure Chemical Industries, Ltd. (90%)), lactic acid fermentation solution of soluble starch was separated and concentrated by electrodialysis, and crude L-lactic acid was used as a sample to obtain polylactic acid. Attempted synthesis.
【００１５】市販L-乳酸約300gを500ml セパラブルフラ
スコに入れ、５〜６mmHgの減圧下、100 ℃で１時間、12
0 ℃で３時間、160 ℃で３時間、段階的に昇温して重縮
合させ、約245gのポリ乳酸を得た。生成ポリ乳酸の分子
量分布及び分子量をゲル浸透クロマトグラフィーにより
測定したところ、図１に示すような分子量分布を持ち、
重量平均分子量Mw7100（ポリスチレン基準）のものであ
った。About 300 g of commercially available L-lactic acid was placed in a 500 ml separable flask and put under reduced pressure of 5-6 mmHg at 100 ° C. for 1 hour.
The temperature was raised stepwise at 0 ° C. for 3 hours and at 160 ° C. for 3 hours for polycondensation to obtain about 245 g of polylactic acid. When the molecular weight distribution and molecular weight of the produced polylactic acid were measured by gel permeation chromatography, it had a molecular weight distribution as shown in FIG.
It had a weight average molecular weight of Mw7100 (based on polystyrene).
【００１６】発酵粗L-乳酸52ｇを100ml のセパラブルフ
ラスコに入れ、10〜15mmHgの減圧下、120 ℃で２時間、
160 ℃で１時間、段階的に昇温加熱して重縮合させた。
約48g の粗ポリ乳酸を回収した。生成粗ポリ乳酸の分子
量分布は図２に示すとおりであり、Mwは4400であった。52 g of fermented crude L-lactic acid was placed in a 100 ml separable flask and put under reduced pressure of 10 to 15 mmHg at 120 ° C. for 2 hours.
Polycondensation was carried out by heating in stages at 160 ° C. for 1 hour.
About 48 g of crude polylactic acid was recovered. The molecular weight distribution of the produced crude polylactic acid is as shown in FIG. 2, and the Mw was 4400.
【００１７】発酵粗L-乳酸約44g を100ml のセパラブル
フラスコに入れ、５〜６mmHgの減圧下、100 ℃で１時
間、120 ℃で３時間、160 ℃で３時間、段階的に昇温加
熱し重縮合させ、約33ｇの粗ポリ乳酸を得た。生成粗ポ
リ乳酸の分子量分布は図３に示すとおりであり、Mw6700
の分子量を持ったものであった。以上のように、減圧
下、100 〜200 ℃で段階的に昇温加熱すれば、無触媒下
においても粗乳酸を重縮合させて、低分子量ポリマーを
製造できる。About 44 g of fermented crude L-lactic acid was placed in a 100 ml separable flask and heated stepwise under reduced pressure of 5 to 6 mmHg at 100 ° C. for 1 hour, 120 ° C. for 3 hours, and 160 ° C. for 3 hours. Then, polycondensation was performed to obtain about 33 g of crude polylactic acid. The molecular weight distribution of the produced crude polylactic acid is as shown in Fig. 3.
It had a molecular weight of. As described above, when the temperature is raised stepwise at 100 to 200 ° C. under reduced pressure, the crude lactic acid can be polycondensed even in the absence of a catalyst to produce a low molecular weight polymer.
【００１８】（実施例２）ポリ乳酸の熱分解によるラク
チドの製造 (i) 熱分解触媒の探索 接触熱分解法によるポリ乳酸のラクチドへの転化触媒と
して、Sb2O3 やオクチル酸錫が適正触媒として知られて
いるが、重金属化合物で有害であること、価格的にも高
価であるため、これに代わり得る使い捨て触媒を探索し
た。(Example 2) Production of lactide by thermal decomposition of polylactic acid (i) Search for thermal decomposition catalyst Sb 2 O 3 and tin octylate are suitable as catalysts for conversion of polylactic acid to lactide by catalytic thermal decomposition method. Although it is known as a catalyst, it is a heavy metal compound, and it is harmful and expensive. Therefore, we searched for a disposable catalyst that can replace it.
【００１９】市販L-乳酸より合成したポリ乳酸（Mw 710
0 ）を試料として、約10 ml のガラス製単蒸留型反応装
置を用い、この反応器にポリ乳酸４ｇと触媒0.04ｇを入
れ、５mmHg減圧下、加熱炉温を約６分間で260 ℃まで昇
温して10分間熱分解し、更に約５分かけて300 ℃まで昇
温し、10分間熱分解させた。分解生成物中には熱的に不
安定な成分が含まれるので、ＮＭＲ法によって分析し、
メチル基の定量から組成を比較した。Polylactic acid synthesized from commercial L-lactic acid (Mw 710
0) as a sample, using a glass simple distillation type reactor of about 10 ml, polylactic acid 4 g and catalyst 0.04 g were put into this reactor, and the heating furnace temperature was raised to 260 ° C. in about 6 minutes under a reduced pressure of 5 mmHg. It was heated and pyrolyzed for 10 minutes, further heated to 300 ° C. over about 5 minutes and pyrolyzed for 10 minutes. Since the thermally decomposed component is contained in the decomposition product, it is analyzed by NMR method,
The compositions were compared by quantitative determination of methyl groups.
【００２０】表１に示すように、Al2O3 、SiO2/Al2O3の
ような固体酸触媒では未分解物が25〜45％も残るに対し
て、FeO 触媒ではSb2O3 やオクチル酸錫触媒と同じく10
0%近い分解率を示し、匹敵する触媒活性を持つことが確
認された。更に、生成物であるラクチド、ラクチル乳
酸、乳酸、その他（3、4 量体成分）の分布もほぼ同じで
あることを見出した。As shown in Table 1, 25 to 45% of undecomposed products remain in solid acid catalysts such as Al 2 O 3 and SiO 2 / Al 2 O 3 , whereas in FeO catalysts, Sb 2 O 3 remains. 10 as well as tin octylate catalyst
It showed a decomposition rate close to 0% and was confirmed to have comparable catalytic activity. Furthermore, it was found that the distributions of the products lactide, lactyl lactic acid, lactic acid and other (3,4 mer components) are almost the same.
【００２１】FeO はSb2O3 に比較して無害、安価である
ため、使い捨てのできる実用触媒である。Since FeO is harmless and cheaper than Sb 2 O 3 , it is a practical catalyst that can be thrown away.
【００２２】[0022]
【表１】 [Table 1]
【００２３】(ii)FeO 触媒による粗ポリ乳酸の接触熱分
解 100ml の冷却器付セパラブルフラスコに実施例１で合成
したMw4400の粗ポリ乳酸約45ｇと触媒として 0.5ｇのFe
O を入れ、10〜15mmHgの減圧下、250 〜270 ℃で１時間
加熱して熱分解した。留出するラクチド留分約38ｇを回
収した。ＮＭＲによる留分組成は、ラクチド（D,L-体／
Meso- 体=52/24）76％、その他（ラクチル乳酸、乳酸、
その他）26％であった。(Ii) Catalytic thermal decomposition of crude polylactic acid with FeO catalyst About 100 g of crude polylactic acid of Mw4400 synthesized in Example 1 and 0.5 g of Fe as a catalyst were placed in a 100 ml separable flask equipped with a condenser.
O was added, and the mixture was heated at 250 to 270 ° C. for 1 hour under reduced pressure of 10 to 15 mmHg for thermal decomposition. About 38 g of the lactide fraction to be distilled out was recovered. The distillate composition by NMR is lactide (D, L-form /
Meso- body = 52/24) 76%, other (lactyl lactic acid, lactic acid,
Others) was 26%.
【００２４】この粗ラクチド留分をメチルイソブチルケ
トンを溶剤に用いて３度再結晶化して精製を試みた。精
製ラクチドのＮＭＲスペクトルを図４に示すが、高純度
で精製できることが確認された。更に、D-又はL-ラクチ
ドとMeso- ラクチドとの分離精製も可能なことが分かっ
た。前記のガラス製単蒸留型反応装置の中に、実施例１
で合成したMw6700の粗ポリ乳酸４ｇと約0.04ｇのFeO を
入れ、４〜６mmHgの減圧下、前記と同じ手順で粗ポリ乳
酸を熱分解した。そして粗ラクチド留分約3.4 ｇを回収
した。The crude lactide fraction was recrystallized three times by using methyl isobutyl ketone as a solvent for purification. The NMR spectrum of the purified lactide is shown in Fig. 4, and it was confirmed that the purified lactide could be purified with high purity. Furthermore, it was found that D- or L-lactide and Meso-lactide can be separated and purified. Example 1 was placed in the glass simple distillation type reactor.
4 g of the crude polylactic acid of Mw6700 synthesized in 4 and about 0.04 g of FeO were put, and the crude polylactic acid was pyrolyzed under the reduced pressure of 4 to 6 mmHg by the same procedure as described above. Then, about 3.4 g of a crude lactide fraction was recovered.
【００２５】ＮＭＲ分析によると、メチル基比で、ラク
チド（D,L-体／Meso- 体＝48/27 ）75％、ラクチル乳酸
14％、乳酸４％、その他（3、4 量体成分）７％の組成で
あった。以上のように、FeO を触媒に用いた粗ポリ乳酸
の熱分解によって、75％以上の収率でラクチドを製造で
き、再結晶化法によって精製可能なことを証明できた。According to NMR analysis, lactide (D, L-form / Meso-form = 48/27) 75% and lactyl lactic acid in terms of methyl group ratio
The composition was 14%, lactic acid 4%, and other (3,4 mer component) 7%. As described above, it was proved that lactide can be produced at a yield of 75% or more by the thermal decomposition of crude polylactic acid using FeO as a catalyst and can be purified by the recrystallization method.
【００２６】（実施例３）精製ラクチドの加水分解によ
る乳酸の製造 実施例２において再結晶化法（溶媒としてメチルイソブ
チルケトンを使用）によって精製したラクチド10ｇに対
して蒸留水18ｇを加え、約80℃に加温後、室温で１週間
放置して、ラクチドの加水分解を試みた。加水分解物の
ＮＭＲスペクトルを図５に示すが、ラクチドは、ラクチ
ル乳酸を経て乳酸にまで加水分解することが確認され
た。Example 3 Production of Lactic Acid by Hydrolysis of Purified Lactide 10 g of lactide purified by the recrystallization method (using methyl isobutyl ketone as a solvent) in Example 2 was added with 18 g of distilled water to give about 80 After heating to ℃, it was left at room temperature for 1 week to try hydrolysis of lactide. The NMR spectrum of the hydrolyzate is shown in FIG. 5, and it was confirmed that lactide hydrolyzes to lactic acid via lactyl lactic acid.
【００２７】但し、乳酸、ラクチル乳酸、ラクチド、水
の間に、平衡関係があるので、過剰の水の共存でのみ 1
00％に近い乳酸を得ることができる。また、ラクチル乳
酸の乳酸への加水分解は遅いので、硫酸等の触媒の添加
が望ましい。However, since lactic acid, lactyl lactic acid, lactide and water have an equilibrium relationship, only in the presence of excess water 1
You can get lactic acid close to 00%. Also, since the hydrolysis of lactyl lactic acid to lactic acid is slow, it is desirable to add a catalyst such as sulfuric acid.
【００２８】[0028]
【発明の効果】本発明によれば、高純度ラクチドを簡易
かつ経済的に製造することができる。本発明のラクチド
の製造方法は、発酵法等で得られる粗乳酸の精製方法に
も利用可能である。According to the present invention, high-purity lactide can be produced easily and economically. The method for producing lactide of the present invention can also be used as a method for purifying crude lactic acid obtained by a fermentation method or the like.
【図１】合成ポリ乳酸の分子量分布を示す図である。FIG. 1 is a diagram showing a molecular weight distribution of synthetic polylactic acid.
【図２】合成粗ポリ乳酸の分子量分布を示す図である。FIG. 2 is a diagram showing a molecular weight distribution of synthetic crude polylactic acid.
【図３】合成粗ポリ乳酸の分子量分布を示す図である。FIG. 3 is a diagram showing a molecular weight distribution of synthetic crude polylactic acid.
【図４】精製ラクチド及びラクチド留分のＮＭＲスペク
トルを示す図である。FIG. 4 shows NMR spectra of purified lactide and lactide fraction.
【図５】ラクチド加水分解物のＮＭＲスペクトルを示す
図である。FIG. 5 is a diagram showing an NMR spectrum of a lactide hydrolyzate.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 池田 光二 北海道札幌市豊平区月寒東２条17丁目２番 １号 工業技術院北海道工業技術研究所内 (72)発明者 平間 康子 北海道札幌市豊平区月寒東２条17丁目２番 １号 工業技術院北海道工業技術研究所内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koji Ikeda 2-17-1, Tsukikanto, Toyohira-ku, Sapporo-shi, Hokkaido Inside Institute of Industrial Science and Technology, Hokkaido Institute of Industrial Technology (72) Yasuko Hirama Tsukisamu, Toyohira-ku, Sapporo-shi, Hokkaido East 2-17-172-1, Institute of Industrial Technology, Hokkaido Institute of Industrial Technology
Claims (4)
のポリ乳酸とした後、酸化第一鉄を触媒として、減圧下
接触熱分解することにより留出するラクチドを得ること
を特徴とするラクチドの製造方法。1. A lactide to be distilled is obtained by subjecting lactic acid to polycondensation under heating under reduced pressure to form low-molecular weight polylactic acid, and then catalytically decomposing under reduced pressure using ferrous oxide as a catalyst. Method for producing lactide.
蒸留して脱水したものである請求項１記載の製造方法。2. The method according to claim 1, wherein the lactic acid is obtained by dehydrating crude lactic acid obtained in the fermentation step by distillation under reduced pressure.
法により精製する請求項１又は２記載の製造方法。3. The production method according to claim 1, wherein the lactide thus obtained is purified by a crystallization method or a recrystallization method.
量のポリ乳酸とした後、酸化第一鉄を触媒として、減圧
下接触熱分解することにより留出するラクチドを得、次
いでこれを加水分解し、乳酸を得ることを特徴とする乳
酸の精製方法。4. A crude lactic acid is subjected to polycondensation by heating under reduced pressure to give a polylactic acid having a low molecular weight, and then lactide to be distilled is obtained by catalytic thermal decomposition under reduced pressure using ferrous oxide as a catalyst. A method for purifying lactic acid, which comprises hydrolyzing to obtain lactic acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6256528A JP2560259B2 (en) | 1994-10-21 | 1994-10-21 | Method for producing lactide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6256528A JP2560259B2 (en) | 1994-10-21 | 1994-10-21 | Method for producing lactide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08119961A true JPH08119961A (en) | 1996-05-14 |
| JP2560259B2 JP2560259B2 (en) | 1996-12-04 |
Family
ID=17293883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6256528A Expired - Lifetime JP2560259B2 (en) | 1994-10-21 | 1994-10-21 | Method for producing lactide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2560259B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011507934A (en) * | 2007-12-26 | 2011-03-10 | クタントン・リミテッド | Method for producing cyclic diester of α-hydroxy acid |
| JP2011074084A (en) * | 1999-03-22 | 2011-04-14 | Purac Biochem Bv | Method of industrial-scale purification of lactic acid |
| JP2014522651A (en) * | 2011-07-15 | 2014-09-08 | プラクシカ・リミテッド | Separation method |
| JP2015525074A (en) * | 2012-06-11 | 2015-09-03 | プラクシカ・リミテッド | Method for producing lactate ester |
| JP2019163221A (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Method for producing glycolide |
| JP2019163222A (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Method for producing glycolide |
-
1994
- 1994-10-21 JP JP6256528A patent/JP2560259B2/en not_active Expired - Lifetime
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011074084A (en) * | 1999-03-22 | 2011-04-14 | Purac Biochem Bv | Method of industrial-scale purification of lactic acid |
| JP2011507934A (en) * | 2007-12-26 | 2011-03-10 | クタントン・リミテッド | Method for producing cyclic diester of α-hydroxy acid |
| JP2014522651A (en) * | 2011-07-15 | 2014-09-08 | プラクシカ・リミテッド | Separation method |
| JP2014522652A (en) * | 2011-07-15 | 2014-09-08 | プラクシカ・リミテッド | Separation method |
| JP2015525074A (en) * | 2012-06-11 | 2015-09-03 | プラクシカ・リミテッド | Method for producing lactate ester |
| WO2019181340A1 (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Glycolide production method |
| JP2019163221A (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Method for producing glycolide |
| JP2019163222A (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Method for producing glycolide |
| WO2019181298A1 (en) * | 2018-03-20 | 2019-09-26 | 株式会社クレハ | Method for producing glycolide |
| CN111741952A (en) * | 2018-03-20 | 2020-10-02 | 株式会社吴羽 | Method for producing glycolide |
| US11001565B2 (en) | 2018-03-20 | 2021-05-11 | Kureha Corporation | Glycolide production method |
| CN111741952B (en) * | 2018-03-20 | 2023-06-09 | 株式会社吴羽 | Process for producing glycolide |
| US11753391B2 (en) | 2018-03-20 | 2023-09-12 | Kureha Corporation | Method for producing glycolide |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2560259B2 (en) | 1996-12-04 |
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