JPS62111976A - Purification of gamma-butyrolactone - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high purity, by separating high- boiling impurities from crude title compound, treating the compound with an alkaline earth metal hydroxide or oxide and distilling the treated product, thereby removing the acid component and water from the compound economically on an industrial scale. CONSTITUTION:A crude gamma-butyrolactone, especially a gamma-butyrolactone containing large amount of acid component having relatively high boiling point and produced by the catalytic hydrogenation of maleic anhydride or its partial hydride is distilled to separate and remove the high-boiling component. The obtained gamma-butyrolactone is added with one or more compounds selected from alkaline earth metal hydroxides and oxides, heat-treated preferably at 120-250 deg.C and distilled to obtain purified gamma-butyrolactone having extremely low content of acid and water and useful as an extraction solvent or an intermediate for pharmaceuticals, agricultural chemicals, particular plasticizers, etc., economically on an industrial scale.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明はγ−ブチロラクトンの精製法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for purifying γ-butyrolactone.

γ−ブチロラクトンは各釉モノマー及びポリマーに対す
る優れた溶解性等、特徴のある物性を有し、しかもその
取扱いが容易であることから各種溶剤及び改良剤等に用
いられている。また、γ−ブチロラクトンは化学反応性
に富み、アンモニア、アミン、イオウ化合物との反応生
成物の他、加水分解反応物、酸化反応物、還元反応生成
物等のγ−ブチロラクトン誘導体を導き、抽出溶剤、医
薬中間体、農薬中間体、特殊可塑剤などの原料に用いら
れる。四にｒ−ブチロラクトンはそれ自体の１に気持性
だけでなく、各種溶剤との糺合せにより種々の有機電解
質特性を有し、コンデンサー電解質溶剤等の用途にも有
効である。γ-Butyrolactone has characteristic physical properties such as excellent solubility in various glaze monomers and polymers, and is easy to handle, so it is used in various solvents and modifiers. In addition, γ-butyrolactone has high chemical reactivity, and in addition to reaction products with ammonia, amines, and sulfur compounds, γ-butyrolactone derivatives such as hydrolysis reaction products, oxidation reaction products, and reduction reaction products are produced, and the extraction solvent It is used as a raw material for pharmaceutical intermediates, agricultural chemical intermediates, special plasticizers, etc. Fourth, r-butyrolactone is not only airy by itself, but also has various organic electrolyte properties when combined with various solvents, and is effective in applications such as capacitor electrolyte solvents.

〔従来の技術〕[Conventional technology]

従来よりγ−ブチロラクトンは工業的には無水マレイン
酸またはその部分水素化物である無水コハク酸、コハク
酸等の水素化反応によって製造され、得られる粗ｒ−ブ
チロラクトン中には中間生成物である無水コノ・り酸、
コ・・り酸斤らびに反応副生物でｋ）ろプロピオン酸、
酪酸、エナント酸等の有機酸類、プロパツール、ブタノ
ール等のアルコール類およびそれらのエステル等が含ま
れている。しかしながら、用途によっては極く徴証の水
分及び酸分の存在なも嫌い、高純度のγ−ブチロラクト
ンが要求され、特にブチロラクトンの精製には専ら蒸留
による処理か行な罎−〕れているが、蒸留のみでは極め
て精密にこれを行っても満足すべき精製効果が得られず
、特に有機酸類等の酸分及び水分の除去が困難である。Conventionally, γ-butyrolactone has been produced industrially by hydrogenation reaction of maleic anhydride or its partially hydrogenated product, succinic anhydride, succinic acid, etc., and the resulting crude r-butyrolactone contains anhydride, which is an intermediate product. Cono-phosphoric acid,
k) filtrate propionic acid, as a reaction by-product;
Contains organic acids such as butyric acid and enanthic acid, alcohols such as propatool and butanol, and their esters. However, depending on the application, highly pure γ-butyrolactone is required because the presence of obvious moisture and acid content is extremely undesirable, and the purification of butyrolactone in particular is carried out exclusively by distillation. Distillation alone does not provide a satisfactory purification effect even if it is carried out very precisely, and in particular it is difficult to remove acids such as organic acids and water.

このため、粗ｒ−ブチロラクトンを鉱酸で処理し、次い
でこれにアルカリ金属の水酸化物、炭酸塩等のアルカリ
を加えて中和した後、蒸留する方法が提案されている。For this reason, a method has been proposed in which crude r-butyrolactone is treated with a mineral acid, then an alkali such as an alkali metal hydroxide or carbonate is added thereto to neutralize it, and then distilled.

（特公昭３３−ＩＡＡ；２号） 〔発明が解決しようとする問題点〕 １．７かしながら、ＬＨ己の＋〃案ブチ法で＆すアルカ
リによってγ−ブチ［フラントンが副反応を’ｉ’　起
り、、γ−オキン酪酸あるいを↑りｙ／−オキンニ醋酸
のアルカリ塩が生成するため、γ−ブチロラクトン中の
酸分は実質的除去されず、ｆ」すγ−ブチロラクトン（
ｆｌ失により回収率が低下ずろという問題があった。′
ｆがλっも、本発明は、γ−ブヂロラクトン中の酸分及
び水分な工秦的有利に除去し、島純度のγ−ブチロラク
トンを取１１↓することを目的とするもの”（二２．ろ
。(Special Publication No. 33-IAA; No. 2) [Problems to be Solved by the Invention] 1.7 However, LH's proposed buty method & When i' occurs, γ-ochynebutyric acid or y/-ochinedicate alkali salt is produced, so the acid content in γ-butyrolactone is not substantially removed, and f's γ-butyrolactone (
There was a problem in that the recovery rate decreased due to loss of fl. ′
Even if f is λ, the purpose of the present invention is to remove the acid content and water content in γ-butyrolactone in an industrially advantageous manner, and to obtain γ-butyrolactone of high purity. reactor.

〔問題点を解決するための手段〕[Means for solving problems]

本発明者等はかかる目的を達成ずべ（鋭意検討Ｉ７た結
果、予め高沸物を分離除去１．てイ４ｉられはｒ−ブチ
ロラクトンの副反応が抑制され、酸分及び水分の著しく
少ないγ−ブチロラクトンが得られることを見出し、本
発明を完成１７た。The inventors of the present invention have achieved this objective (as a result of intensive studies), it has been found that by separating and removing high-boiling substances in advance, the side reactions of r-butyrolactone can be suppressed, and γ- It was discovered that butyrolactone could be obtained, and the present invention was completed17.

すなわち、本発明の要旨はｒ−ブチロラクトンを蒸留精
製するに多ンたり、γ−）゛チロラクトンな蒸留処理す
ることによって予め高沸点物を分離除去し、次いでアル
カリ土類金属の酸化物または水酸化物から選ばれた少な
（とも一種の化合物を添加し、熱処理した後、蒸留する
ことを特徴とするγ−ブチロラクトンのｆｆ製表法存す
る。In other words, the gist of the present invention is to purify r-butyrolactone by distillation, or to pre-separate and remove high-boiling substances by distilling γ-)tyrolactone, and then to remove alkaline earth metal oxides or hydroxides. There is an FF manufacturing method for γ-butyrolactone, which is characterized by adding a small amount of a selected compound, heat treatment, and distillation.

以下、本発明につき更に詳細に説明する。The present invention will be explained in more detail below.

本発明に適用′きれるγ−ブチロラクトンは無水マレ・
ｆン酸またはその部分水素化物の気相または液ａ接触水
素化法、／１４ｔ−ブタンジオールの環化脱水素法、γ
−ヒドロキシブチルアルデヒド、ｒ−ヒドロキン酪酸の
環化等の種々の方法で製造されるが、特に無水マレイン
酸またはその部分水素化物の接触水素化反応によって得
られる比較的高沸点の酸分を多（含有するγ−ブチロラ
クトンに適用するのが好適である。該無水マレイン酸の
部分水素化物としては無水コハク酸、コハク酸等が挙げ
られ、これらの原料は単独または混合物として用いられ
る。水素化反応に用いられる触媒としては所期の水素化
油性を持つ任意のものが使用可能でカ）す、各種の助触
媒で改良されたニッケル触媒、コバルト触媒、パラジウ
ム触媒及び銅触媒等が知られている。水素化反応は／〜
／ｋＯｋｇ／ｃＩＩの反応圧力、１００〜３５０℃の反
応温度の条件下に液相または気相で行なわれろ。該反応
によって得られる反応生成物中にはｒ−ブチロラクトン
以外に、テトラヒドロフラン、中間生成物でｋ）る無水
コハク酸及びコハク酸、ならびに反応副生物であるプロ
パツール、ブタノール等のアルコール類、プロピオン酸
、酪酸、エナント酸等の有機酸類およびこれらのエステ
ル類、高沸物、生成水等が含有されている。γ-Butyrolactone that can be applied to the present invention is anhydrous male
f Gas phase or liquid a catalytic hydrogenation method of hydronic acid or its partial hydride, /14 cyclization dehydrogenation method of t-butanediol, γ
-Hydroxybutyraldehyde, r-hydroquine is produced by various methods such as cyclization of butyric acid, but in particular, a relatively high-boiling acid component obtained by the catalytic hydrogenation reaction of maleic anhydride or its partial hydride is It is suitable to apply to γ-butyrolactone containing. Examples of the partially hydrogenated product of maleic anhydride include succinic anhydride, succinic acid, etc., and these raw materials can be used alone or as a mixture. In the hydrogenation reaction. Any catalyst that can be used has the desired hydrogenated oil properties; nickel catalysts, cobalt catalysts, palladium catalysts, copper catalysts, etc. improved with various promoters are known. The hydrogenation reaction is/~
The reaction may be carried out in the liquid phase or gas phase under the conditions of a reaction pressure of /kOkg/cII and a reaction temperature of 100 to 350°C. In addition to r-butyrolactone, the reaction products obtained by this reaction include tetrahydrofuran, succinic anhydride and succinic acid as intermediate products, and reaction by-products such as propatool, alcohols such as butanol, and propionic acid. , organic acids such as butyric acid and enanthic acid, their esters, high-boiling substances, and produced water.

本発明方法は上記反応生成物を蒸留処理によって高沸点
物を分離除去し、得られたγ−ブチロラクトンにアルカ
リ土類金属の酸化物または水酸化物を添加して熱処理し
た後、蒸留することにより、酸分及び水分の著しく少な
いγ−ブチロラクトンを取得することを特徴とするもの
である。The method of the present invention involves separating and removing high-boiling substances from the above reaction product by distillation, adding an alkaline earth metal oxide or hydroxide to the obtained γ-butyrolactone, heat-treating it, and then distilling it. This process is characterized by obtaining γ-butyrolactone with significantly low acid content and water content.

上記反応生成物からの高沸点物の蒸留分離は理論段数、
？段ＪＪ上の蒸留塔を用いて、通常減圧痔 下、債ましく、？００〜タθ０朋Ｈｇ圧力下で蒸留１．
て篩沸点物を缶出させて分離し、−万γ−ブチロ−７り
トン分は塔頂ある〜・はサイドカットにより’渭１１４
　Ｆせて抜出すことにより行なわれる。The distillation separation of high-boiling substances from the above reaction products involves the number of theoretical plates,
? Using a distillation column on stage JJ, usually under reduced pressure, most likely, ? Distillation under Hg pressure 1.
The boiling point material is taken out from the sieve and separated, and 7 tons of γ-butyro is collected at the top of the column by side cutting.
This is done by folding it and pulling it out.

得られたγ−ブナ［コラクトン分はそのまま或いはさら
に低沸点物を分離した後、アルカリ土類金属の酸化物ま
たは水酸化物を添加して熱処理を行う。該熱処理は熱処
理釜あるいは蒸留塔の釜のいずれで行ってもよい。該熱
処理を蒸留塔の釜で実施する場合には上記ｒ−ブチロラ
クトン分を蒸留塔に供給し、釜にアルカリ土類金属の酸
化物または水酸化物を添加して熱処理し、屹頂より低沸
物を角田させ、供給段より下部の側流より製品ｒープチ
ロラクトンを抜出すことにより行なうか、または上記γ
ープチロラクトン分より低沸点物を分離したｒ−ブチロ
ラクトンを蒸留塔に供給し、釜にアルカリ土類金属の酸
化物または水酸化物を添加して熱処理し、ｒ一ブチロラ
クトンを留出させることにより実施される。The obtained γ-buna [colactone component may be used as it is or after further separating low boiling point substances, an alkaline earth metal oxide or hydroxide is added and heat treatment is performed. The heat treatment may be performed in either a heat treatment pot or a distillation column pot. When the heat treatment is carried out in a pot of a distillation column, the r-butyrolactone component is supplied to the distillation column, and an alkaline earth metal oxide or hydroxide is added to the column and heat-treated to obtain a lower boiling point than the top. This can be carried out by turning the product into a corner and extracting the product r-butyrolactone from the side stream below the supply stage, or by the above-mentioned γ
The process is carried out by supplying r-butyrolactone from which low-boiling substances have been separated from the butyrolactone component, and adding an alkaline earth metal oxide or hydroxide to the pot and heat-treating it to distill out r-butyrolactone. Ru.

本発明方法において用いられるアルカリ土類金属の酸化
物または水酸化物としてはマグネシウム、カルシウム、
バリウム、ストロンチウム等のアルカリ土類金属の酸化
物または水酸化物が挙げられ、月俸的には酸化マグネシ
ウム・、酸化カルシウム、酸化バリウム、水酸化マグネ
シウム、水酸化力ルンウム、水酸化バリウム等が好適で
ある。これらの化合物は単独またはこれらの混合物の〜
・ずれで用いてもよい。該アルカリ土類金属の酸化物ま
たは水酸化物の添加量はごく少量あればよく、例えばｒ
−ブナロラクトン中に含有されている酸分７当普〔コハ
ク酸として換算した値フに対して，通常７当量Ｊ゛Ｊ上
好ましくは７〜−〇当量の範囲が好適で七，ろ。」−記
添加物の添加方法としては上船添加物の粉末を直接処理
釜に添加してもよいか、該添力１］物をｒ−ブチロラク
トンに懸濁させたスラリー状態で処理釜に連続的に供給
するのが望ま１−い。The alkaline earth metal oxides or hydroxides used in the method of the present invention include magnesium, calcium,
Examples include oxides or hydroxides of alkaline earth metals such as barium and strontium, and magnesium oxide, calcium oxide, barium oxide, magnesium hydroxide, hydroxide, barium hydroxide, etc. are preferred in terms of monthly salary. be. These compounds alone or in mixtures of ~
・May be used at different times. The amount of the alkaline earth metal oxide or hydroxide added may be very small; for example, r
- The acid content contained in bunarolactone is usually 7 equivalents (based on the value calculated as succinic acid), preferably in the range of 7 to -0 equivalents. As for the method of adding the additives mentioned above, it is possible to add the powder of the onboard additive directly to the processing tank, or to continuously add the additive (1) in the form of a slurry suspended in r-butyrolactone to the processing tank. It is desirable that the supply be provided in a timely manner.

杢゛発明においＣけγープチロラクトンに上記添加物を
添加した後、／００〜．２！０℃，望まし《は／コθ〜
．２に７１７℃の温度で、滞留時間と｛７て数分以上、
望ましくは７０分〜３時間、熱処理した後、蒸留して製
品γープチロラクトンを取得１る。蒸留は減圧または常
圧下に、回分式または連続式の蒸留により行うことがで
きる。杢゛In the invention, after adding the above additive to carbon gamma-butyrolactone, /00~. 2!0℃, desired《ha/koθ~
．． 2. At a temperature of 717°C, the residence time is {7 or more than a few minutes,
After heat treatment, preferably for 70 minutes to 3 hours, the product is distilled to obtain γ-butyrolactone. Distillation can be carried out by batch or continuous distillation under reduced pressure or normal pressure.

」一Ｎ＋ｊ熱処理を蒸留塔で実施する場合には釜にγ一
プチロラクトンと上記添加物を供給し、処理温度７．２
θ℃〜一Ｓ−　Ｏ℃で熱処理しながら、蒸留を行っても
よい。上記釜内に添加した添加物はγープチロラクトン
中の有機酸と反応して有機酸塩＆Ｊ′ｒ′３成して液体
状態となり釜内の底部に滞留する。従って、γープチロ
ラクトンと上記添加物を連ｐ１一的に供給している場合
には連続的にｒ−ブナロラクトン中の有機酸と反応して
生成した該＆別物塩は底部より抜出しが可能である。し
かしなから、処理温度かｌ．２０℃以下では上官〔１生
成塩の粘度が著しく高くなり抜出しができなくなるので
、処理温度を７１０℃以上で行うのが望ましい。When carrying out heat treatment in a distillation column, γ-butyrolactone and the above additives are supplied to the pot, and the treatment temperature is 7.2
Distillation may be carried out while heat-treating at θ°C to 1S-O°C. The additive added to the pot reacts with the organic acid in γ-butyrolactone to form an organic acid salt &J'r'3, becomes liquid, and stays at the bottom of the pot. Therefore, when γ-butyrolactone and the above-mentioned additives are continuously fed, the &2 salt produced by continuous reaction with the organic acid in r-bunalolactone can be extracted from the bottom. However, due to the processing temperature l. If the temperature is lower than 20°C, the viscosity of the salt produced in Kamigana [1] becomes extremely high and it becomes impossible to extract it, so it is desirable to carry out the treatment at a temperature of 710°C or higher.

〔実施例〕〔Example〕

次に，本発明を実施例により財に詳イ１｛１に説明する
が、本発明はその要旨ケ超えない限り、以下の実施例に
限定されろものではない。Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

実施例／ 無水マレインを接触水素化反応して得られたｒ−ブチロ
ラクトンを含有する反応生成物をまず高沸点分離塔（実
段数ノθ段、塔頂温度ｉｂｓ℃及び塔頂圧力．３：２０
Ｈ１１ｇの条件）にて高沸点物を塔底より抜出し、一万
、留出液を低沸点分離塔（実段数、？一段、塔底温度一
〇７℃及び塔底圧力？４ｊｍｉＨｇの条件ンにて塔頂よ
り低沸点物を留出させ、一万段数一段目の側流よりｒ−
ブチロラフ１・ンを抜出した。得られたγープチロラク
トンは純度？？．５７重ｉ％、酸分（コハク酸としてＪ
　／ｔｅｌθｐｐｌｎ及び水分コ７　ｏ　ｐｐｍであっ
た。Example/The reaction product containing r-butyrolactone obtained by catalytic hydrogenation of anhydrous maleic was first transferred to a high boiling point separation column (actual number of stages θ stages, tower top temperature ibs °C and tower top pressure 3:20).
The high boiling point substances were extracted from the bottom of the column under conditions of 11 g of Hg), and the distillate was transferred to a low boiling point separation column (actual number of plates: ?1 stage, bottom temperature of 107°C and bottom pressure of ?4 mHg). The low boiling point substances are distilled from the top of the column, and the r-
Butyrolav 1.n was extracted. Is the obtained γ-butyrolactone pure? ? ．． 57% by weight, acid content (J as succinic acid)
/telθppln and water content was 70 ppm.

単蒸留装置を取付けた８ｆｔｊｏＯ　ｒａｔ０３つロフ
ラスコに上ｈ己γ−プチロラクトンコθθ重菫部を仕込
み、これに酸化力ルンウム粉末なθ０ｇ、７重廿部添２
１１　ｔ、　（これはγ−ブチロラクトン中の酸分Ｃコ
ハク酸として）に対して９倍当量に相当１゛る。）、攪
拌しながら昇温すると分散していた酸化力ルンウムは沸
騰状態で液状になりフラスコ底部に滞留していた。沸点
（，２θｔ℃）でＳ分間熱処理した後、γ−ブチロラク
トンを単蒸留で追い出した。留出物の酸分及び水分のｋ
は第１表に示す通りであった。Into an 8ft x 3-bottle flask equipped with a simple distillation device, add γ-butyrolactone, θθ, and 2 parts of oxidizing power powder, and 2 parts of 7 parts.
11t, which corresponds to 9 times the equivalent of succinic acid in γ-butyrolactone. ), when the temperature was raised while stirring, the dispersed oxidizing power turned into a liquid in a boiling state and remained at the bottom of the flask. After heat treatment at the boiling point (,2θt°C) for S minutes, γ-butyrolactone was removed by simple distillation. Acid content and moisture k of distillate
were as shown in Table 1.

実施例−〜亭及び比較例７〜ｙ 実施例／において、添加剤の種類及び添加量を第１弐の
ように変えたこと以外は実施例／と同様にして行った。Examples 1 and 7 and Comparative Examples 7 and y The same procedures as in Example 1 were carried out except that the type and amount of additives were changed as in Example 1.

結果を第１表に示す。The results are shown in Table 1.

第１表 ＊１　；酸分はコハク酸とｔ７てＭ　ｎシ、この酸分／
当世に対１′る添加剤の当量比で表わした値＊２　：　
γ−ブチロラクトンをｇｏ％留出させた留出液中の酸分
と水分の址 比ａ例Ｓ 無水マレイン酸を接触水素化反応して得られたｒ−ブチ
ロラクトンを含有する反応生成物を軽沸分離塔〔実段数
２０段、塔底温度、２／、２℃塔底圧カクｌ−！；ｖ＊
Ｈｇの条件）にて、塔頂よりＨｇ、塔頂温度／Ａ？、５
℃の条件〕にて塔頂よりγ−ブチロラクトンを抜き出し
た。得られたγ−ブチロラクトンは純度タデ、／！［有
］、酸分子　／　ｏ　ｐｐｍ及び水分Ａ　ｒ　ｏ　ｏ　
ｐｐｍであった。Table 1 *1; Acid content is succinic acid and t7, M nshi, this acid content/
Value expressed as the equivalent ratio of additive to 1' to the current value *2:
Acid content and moisture ratio in a distillate obtained by distilling γ-butyrolactone to % Example S A reaction product containing r-butyrolactone obtained by catalytic hydrogenation of maleic anhydride Separation column [actual number of plates: 20, bottom temperature: 2/2°C, bottom pressure: 1-! ;v*
Hg condition), Hg from the top of the column, top temperature/A? , 5
γ-butyrolactone was extracted from the top of the column under the following conditions: The obtained γ-butyrolactone has a purity of Polygonum, /! [Yes], acid molecules / o ppm and moisture A r o o
It was ppm.

単蒸留装置を取り付けた容量！；０ＯＦＩＩ０３つ目フ
ラスコに上記γ−プチロラクトンコθＯ重蓋部を仕込み
、これに酸化カルシウム粉末０．３６重蓋部添加しくこ
れはγ−ブチロラクトン中の酸分（無水コノ１り酸に換
算した値〕に対して参倍当量に相当する〕攪拌しなから
昇温し、分散していｔこ酸化カルシウムは沸騰状態で像
状になりフラスコ底部に滞留していた。沸点（−０４℃
）で５分間熱処理した後、γ−ブチロラクトンを単蒸留
で追い出した。留出物の酸分、は貿出不／Ｓ％の留分は
、７ざｐｐｍ、それ以降の留出成分（１５％〜ｇｏ％留
出率の留分）は３　／　’Ｌ）ｐｍで、かつ水分は７０
０θｐｐｍであった。Capacity with simple distillation equipment installed! ;0OFII0 Into the third flask, charge the above γ-butyrolactone θO heavy lid, and add 0.36 heavy lid of calcium oxide powder to this. This is the acid content in γ-butyrolactone (value converted to cono-monolytic anhydride). The temperature was raised without stirring, and the calcium oxide was dispersed in a boiling state and remained at the bottom of the flask.The boiling point (-04°C)
) for 5 minutes, γ-butyrolactone was removed by simple distillation. The acid content of the distillate is 7 ppm for the non-exportable/S% fraction, and 3/'L) pm for the distillate components after that (fraction with a distillation rate of 15% to go%). , and the water content is 70
It was 0θppm.

〔発明の効果〕〔Effect of the invention〕

本発明によれば、ｒ−ブチロラクトン中の酸分及び水分
を工業的有利に除去し、高純度のγ−ブチロラクトンを
得ることができる。According to the present invention, the acid content and moisture in r-butyrolactone can be industrially advantageously removed to obtain highly pure γ-butyrolactone.

Claims (2)

【特許請求の範囲】[Claims] （１）γ−ブチロラクトンを蒸留精製するにあたり、γ
−ブチロラクトンを蒸留処理することによつて予め高沸
点物を分離除去し、次いでアルカリ土類金属の酸化物ま
たは水酸化物から選ばれた少なくとも一種の化合物を添
加し、熱処理した後、蒸留することを特徴とするγ−ブ
チロラクトンの精製方法(1) When purifying γ-butyrolactone by distillation, γ
- Preliminarily separating and removing high-boiling substances by distilling butyrolactone, then adding at least one compound selected from alkaline earth metal oxides or hydroxides, heat-treating, and then distilling. A method for purifying γ-butyrolactone characterized by （２）γ−ブチロラクトンが、無水マレイン酸またはそ
の部分水素化物を接触水素化して得られたγ−ブチロラ
クトンであることを特徴とする特許請求の範囲第１項記
載のγ−ブチロラクトンの精製方法(2) The method for purifying γ-butyrolactone according to claim 1, wherein the γ-butyrolactone is γ-butyrolactone obtained by catalytic hydrogenation of maleic anhydride or a partially hydrogenated product thereof.