JPH0653704B2 - Method for purifying sorbic acid - Google Patents
Method for purifying sorbic acidInfo
- Publication number
- JPH0653704B2 JPH0653704B2 JP61058093A JP5809386A JPH0653704B2 JP H0653704 B2 JPH0653704 B2 JP H0653704B2 JP 61058093 A JP61058093 A JP 61058093A JP 5809386 A JP5809386 A JP 5809386A JP H0653704 B2 JPH0653704 B2 JP H0653704B2
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- JP
- Japan
- Prior art keywords
- sorbic acid
- crude
- dissolved
- tar
- dissolving
- 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.)
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、クロトンアルデヒドとケテンとの反応で得ら
れたポリエステルを分解し、反応液から分離した粗ソル
ビン酸を精製せしめる方法に関する。TECHNICAL FIELD The present invention relates to a method for decomposing a polyester obtained by a reaction between crotonaldehyde and ketene, and purifying crude sorbic acid separated from a reaction solution.
（従来技術及びその問題点） ソルビン酸は、クロトンアルデヒドとケテンの反応によ
って得られたポリエステルを分解することにより製造さ
れる。分解法としては、塩酸分解法、アルカリ分解法、
熱分解法等があるが、この中、塩酸分解法は異性体の生
成を伴うことなく、分解成績上も収率的に、かつ品質的
に最も有利であることが知られている。しかし、いずれ
の場合においても反応中に副生したタール分がポリエス
テル残渣と共に不純物として存在するため、特別の精製
工程を必要とする問題がある。又、比較的優位な塩酸分
解法に於いても、この課題が残り、ポリエステルを分解
した後、冷却・過して得られる粗ソルビン酸はタール
分を含有している。(Prior art and its problems) Sorbic acid is produced by decomposing the polyester obtained by the reaction of crotonaldehyde and ketene. As the decomposition method, hydrochloric acid decomposition method, alkali decomposition method,
There are thermal decomposition methods and the like. Among them, the hydrochloric acid decomposition method is known to be most advantageous in terms of yield and quality in terms of decomposition results without generation of isomers. However, in any case, since the tar component by-produced during the reaction is present as an impurity together with the polyester residue, there is a problem that a special refining step is required. Further, even in the comparatively superior hydrochloric acid decomposition method, this problem remains, and the crude sorbic acid obtained by cooling and passing after decomposing the polyester contains tar.
従来、該粗ソルビン酸の精製には活性炭処理法、水又は
水＋有機溶媒による再結晶法、石油に溶解して蒸溜精製
する方法がある。このような粗ソルビン酸の精製法は古
くから研究が行なわれ、現在では上記の精製法の組合せ
により高品位のソルビン酸を得るに至っている。Conventionally, the crude sorbic acid can be purified by an activated carbon treatment method, a recrystallization method with water or water + organic solvent, and a distillation purification method by dissolving in petroleum. The purification method of such crude sorbic acid has been studied for a long time, and at present, high-grade sorbic acid has been obtained by combining the above-mentioned purification methods.
しかしながら、上記の精製法単独では高品位のソルビン
酸を得るのは非常に困難である。活性炭処理法というの
は粗ソルビン酸をカセイソーダで溶解させた時にソルビ
ン酸と共に溶解するタール分を除去する方法であるが、
活性炭処理后も溶解液は黄色を呈しており、この脱色に
は非常に大量の活性炭を要する問題がある。However, it is very difficult to obtain high-quality sorbic acid by the above-mentioned purification method alone. The activated carbon treatment method is a method of removing the tar component that dissolves together with sorbic acid when the crude sorbic acid is dissolved with caustic soda.
The solution remains yellow after the activated carbon treatment, and there is a problem that a very large amount of activated carbon is required for this decolorization.
粗ソルビン酸中のタール分は、通常４〜６％程度含まれ
ており、再結晶法のみで精製しようとしても、数回繰り
返す必要があり、エネルギーコストとその工程の複雑さ
の問題から実際的ではない。The tar content in the crude sorbic acid is usually contained in the range of 4 to 6%, and it is necessary to repeat several times even if it is intended to purify it only by the recrystallization method, and it is practical because of the problems of energy cost and complexity of the process. is not.
石油に溶解して蒸溜精製する方法は前の２者に比べ容易
でかつ優れた精製効果を有するが、ソルビン酸湿ケーキ
からの残存溶剤を完全に除去することは非常に難しい。The method of distilling and refining by dissolving in petroleum is easier and more excellent than the former two methods, but it is very difficult to completely remove the residual solvent from the wet cake of sorbic acid.
以上の理由から、活性炭処理法と水又は水と有機溶媒に
よる再結晶法の組み合わせ、あるいは、石油に溶解し蒸
留精製する方法と再結晶法の組み合わせにより精製を行
なう必要がある。このためその精製工程は複雑なものと
なり、かなりのエネルギーコストや活性炭の原材料費が
必要となる欠点があった。For the above reasons, it is necessary to carry out the purification by a combination of the activated carbon treatment method and the recrystallization method using water or water and an organic solvent, or a combination of the method of dissolving in petroleum and the distillation purification and the recrystallization method. For this reason, the refining process becomes complicated, and there is a drawback that a considerable energy cost and raw material cost of activated carbon are required.
（問題点を解決するための手段） 本発明者は上記の従来法の欠点を考慮した上で鋭意検討
を重ねた結果、これに比べ、非常に簡単で、かつ低コス
トによる精製法を見出すに至った。即ち本発明はクロト
ンアルデヒドとケテンとの反応で得られたポリエステル
を分解し、反応液から分離した粗ソルビン酸を精製せし
めるソルビン酸の製造方法において粗ソルビン酸を弱ア
ルカリを用いＰＨを７以下、好ましくは６以下で溶解す
ることを特徴とするソルビン酸の精製方法である。(Means for Solving Problems) The present inventor has conducted intensive studies after considering the drawbacks of the above-mentioned conventional methods, and as a result, in comparison with this, a purification method with a very simple and low cost was found. I arrived. That is, the present invention decomposes the polyester obtained by the reaction of crotonaldehyde and ketene, in the method for producing sorbic acid to purify the crude sorbic acid separated from the reaction solution, the crude sorbic acid is a weak alkali pH of 7 or less, It is preferably a method of purifying sorbic acid, which is characterized by dissolving at 6 or less.
粗ソルビン酸をカセイソーダのような強アルカリで溶解
せしめる時、そのＰＨ管理が非常に重要な問題であっ
た。ＰＨが高過ぎると、溶解液の活性炭処理効果が激し
く低下するのである。これは粗ソルビン酸中のタール分
がカルボキシル基を有しており、そのＰＨ条件により、
タール分も中和されるためであると考えられる。When the crude sorbic acid was dissolved in a strong alkali such as caustic soda, its pH control was a very important issue. If the pH is too high, the effect of treating the solution with activated carbon will be significantly reduced. This is because the tar content in the crude sorbic acid has a carboxyl group, and depending on the PH conditions,
It is considered that the tar content is also neutralized.
本発明者はこうした粗ソルビン酸中のタール分の挙動に
着目し、鋭意検討を重ねた結果、弱アルカリを用いて低
いＰＨのもとで粗ソルビン酸を溶解させることにより、
該タール分の溶解を極力抑えることができ、タール分を
含まないソルビン酸アルカリ塩水溶液が得られることを
見出したのである。The present inventor paid attention to the behavior of the tar component in such crude sorbic acid, and as a result of extensive studies, by dissolving the crude sorbic acid under low pH using a weak alkali,
It has been found that the dissolution of the tar component can be suppressed to the utmost and an aqueous sorbic acid alkali salt solution containing no tar component can be obtained.
弱アルカリを用いても、例えばＰＨ７以上で、ソルビン
酸を完全に中和する条件のもとでは上記の効果は全く得
られない。溶解ＰＨは７以下、好ましくは６以下とし、
未反応ソルビン酸が溶解するようなソルビン酸濃度条件
あるいは温度条件が必要である。即ち、弱アルカリを用
いても、ＰＨを７以上で溶解すれば、黄色味を帯びた低
分子タールが溶解を始める。このようなタール分は例え
ば活性炭を用いて完全に除去するのは難しく、結局カセ
イソーダで溶解した時と同様の量の活性炭が必要となっ
てしまうのである。Even if a weak alkali is used, the above effects cannot be obtained at all, for example, at a pH of 7 or more under the condition of completely neutralizing sorbic acid. The dissolved PH is 7 or less, preferably 6 or less,
Sorbic acid concentration conditions or temperature conditions are required so that unreacted sorbic acid is dissolved. That is, even if a weak alkali is used, if PH is dissolved at 7 or more, the yellowish low-molecular tar starts to dissolve. It is difficult to completely remove such a tar component using, for example, activated carbon, and eventually, the same amount of activated carbon as when dissolved with caustic soda is required.
ＰＨを６以下に管理し、弱アルカリで溶解すると、該タ
ール分は殆んど溶解せず、不溶タール分は沈殿してい
る。沈殿しているタールの性状は、ポリエステルの分解
条件により異なるが、概して流動性があり、分液槽にて
タールを分液除去することが可能である。この場合滞留
時間は、0.5ＨＲ以上とることが好ましい。タールの流
動性が乏しい場合は少量の吸着剤を添加して溶解し、
過することができる。吸着剤としては活性炭の他、珪藻
土や活性白土等も使用できる。この場合、不溶性のター
ル分を吸着させることを目的とするものであるから通常
の活性炭処理法に比べ、はるかに少ない量で済む。When the pH is controlled to 6 or less and dissolved in a weak alkali, the tar content is hardly dissolved and the insoluble tar content is precipitated. The property of the precipitated tar varies depending on the decomposition conditions of the polyester, but is generally fluid, and the tar can be separated and removed in a separating tank. In this case, the residence time is preferably 0.5 HR or more. If tar has poor fluidity, add a small amount of adsorbent to dissolve it,
Can have. As the adsorbent, in addition to activated carbon, diatomaceous earth or activated clay can be used. In this case, since the purpose is to adsorb the insoluble tar component, the amount required is much smaller than that in the usual activated carbon treatment method.
かくして得られたソルビン酸アルカリ塩（および未反応
ソルビン酸）水溶液は、タール分を含有せず、ほとんど
無色に近い。該水溶液を常法により酸性とし、過し、
水洗することにより無色のソルビン酸湿ケーキが得られ
る。該ケーキを常法により乾燥すれば、白色のソルビン
酸が得られる。The aqueous solution of alkali sorbic acid salt (and unreacted sorbic acid) thus obtained does not contain tar and is almost colorless. The aqueous solution is acidified by a conventional method, and then,
A colorless wet cake of sorbic acid is obtained by washing with water. When the cake is dried by a conventional method, white sorbic acid is obtained.
ソルビン酸湿ケーキを用いて水、あるいは水溶剤の再結
晶を行なってさらに商品質のソルビン酸を得ることもも
ちろん可能である。Of course, it is also possible to recrystallize water or a water solvent using a wet cake of sorbic acid to obtain sorbic acid of commercial quality.
粗ソルビン酸の溶解条件としては、ＰＨは、できるだけ
低い方が好ましく、そのためには、温度を４０℃以上、
好ましくは５０℃以上に保ち、未反応ソルビン酸の析出
を防止することが望まれる。As a condition for dissolving the crude sorbic acid, the pH is preferably as low as possible. For that purpose, the temperature is 40 ° C. or higher,
It is preferable to keep the temperature at 50 ° C. or higher to prevent precipitation of unreacted sorbic acid.
また使用する弱アルカリとしては、MgO，CaO，BaO，Mg
(OH)2，Ca(OH)2，Ba(OH)2，に代表されるアルカリ土類
金属の酸化物、水酸化物、NaHCO3，KHCO3に代表される
アルカリ金属の炭酸塩あるいは重炭酸塩が挙げられる。The weak alkalis used are MgO, CaO, BaO, Mg
Alkaline earth metal oxides and hydroxides represented by (OH) 2 , Ca (OH) 2 and Ba (OH) 2 , carbonates or bicarbonates of alkali metals represented by NaHCO 3 and KHCO 3. Examples include salt.
≪発明の効果≫ 粗ソルビン酸の精製方法として、ＰＨを７以下好ましく
は６以下で粗ソルビン酸を溶解し、不溶タール分のみを
除去するという非常に簡単な操作により、タール分を効
果的に除去することが可能となった。<< Effect of the Invention >> As a method for purifying crude sorbic acid, the tar content is effectively reduced by a very simple operation of dissolving the crude sorbic acid at a pH of 7 or less, preferably 6 or less and removing only the insoluble tar content. It became possible to remove it.
実施例１ 塩酸分解法によって得られた粗ソルビン酸１００ｇ（水
分２０％、タール分４％、ソルビン酸７６％）へ水６０
０ｇを加え撹拌してスラリー化させた。温度を６０℃迄
上げた後、酸化マグネシウムをＰＨ５〜5.5を保ちなが
ら少量づつ加えた。最終的にＰＨを5.3に調整した後、
温度を６０℃に保ちながら１時間静置した。上層液をと
り、冷却しながら１０％塩酸を加え、温度２０℃でＰＨ
を３に調整した。こうして得られたスラリーを過し、
別された湿ソルビン酸ケーキを１の水で洗浄した。Example 1 100 g of crude sorbic acid (water content 20%, tar content 4%, sorbic acid 76%) obtained by hydrochloric acid decomposition method to water 60
0 g was added and stirred to make a slurry. After raising the temperature to 60 ° C., magnesium oxide was added little by little while maintaining PH5 to 5.5. After finally adjusting the PH to 5.3,
The temperature was kept at 60 ° C., and the mixture was left standing for 1 hour. Take the upper layer liquid, add 10% hydrochloric acid while cooling, and add PH at 20 ° C.
Was adjusted to 3. Pass the slurry thus obtained,
The separated wet sorbic acid cake was washed with 1 part of water.
こうして、ソルビン酸湿ケーキ９３ｇ（水分２０％、ソ
ルビン酸８０％）を得た。また、液中約１ｇのソルビ
ン酸が溶解しており、湿ケーキと液中に含まれたソル
ビン酸の収率は、粗ソルビン酸中のソルビン酸に対して
９９％であった。Thus, 93 g of wet sorbic acid cake (water content 20%, sorbic acid 80%) was obtained. Further, about 1 g of sorbic acid was dissolved in the liquid, and the yield of sorbic acid contained in the wet cake and the liquid was 99% with respect to sorbic acid in the crude sorbic acid.
該ソルビン酸湿ケーキを常法により乾燥すると、白色の
ソルビン酸が得られ、純度は99.7％であった。When the wet cake of sorbic acid was dried by a conventional method, white sorbic acid was obtained, and the purity was 99.7%.
さらに、ソルビン酸湿ケーキを用いて、常法に従い、メ
タノール水系で再結晶させ、過、乾燥した。かくして
得られたソルビン酸１ｇを１０mlのメタノールに溶解し
た時の色価は、３５０μｍの波長における透過率を分光
々度計を用いて測定したところ、95.5％であり、ソルビ
ン酸１ｇを1N−NaOH水溶液に溶解した時の色価は４００
μｍの波長における透過率で96.0％であった。Further, using a wet cake of sorbic acid, it was recrystallized in an aqueous methanol system according to a conventional method, dried and dried. When 1 g of the sorbic acid thus obtained was dissolved in 10 ml of methanol, the color value was 95.5% when the transmittance at a wavelength of 350 μm was measured using a spectrophotometer, and 1 g of sorbic acid was dissolved in 1N-NaOH. Color value when dissolved in aqueous solution is 400
The transmittance at a wavelength of μm was 96.0%.
実施例２ 実施例１に於て、活性炭（白サギＡ、武田薬品工業
（株）製）１ｇを加えて、同じ条件で粗ソルビン酸を溶
解した後、溶解液を６０℃のままで過し、液を実施
例１と同様の手順で処理した。Example 2 In Example 1, 1 g of activated carbon (White heron A, manufactured by Takeda Pharmaceutical Co., Ltd.) was added and the crude sorbic acid was dissolved under the same conditions, and then the solution was left at 60 ° C. The solution was treated in the same procedure as in Example 1.
その結果、ソルビン酸湿ケーキ９２ｇ（水分２０％、ソ
ルビン酸８０％）を得た。湿ケーキと液中に含まれた
ソルビン酸の収率は、粗ソルビン酸中のソルビン酸に対
して９８％であった。As a result, 92 g of wet cake of sorbic acid (water content 20%, sorbic acid 80%) was obtained. The yield of sorbic acid contained in the wet cake and the liquid was 98% based on the sorbic acid in the crude sorbic acid.
該ソルビン酸湿ケーキを常法により乾燥すると、白色の
ソルビン酸が得られ、純度は99.8％であった。When the wet cake of sorbic acid was dried by a conventional method, white sorbic acid was obtained, and the purity was 99.8%.
さらに、ソルビン酸湿ケーキを用いて、常法に従い、メ
タノール−水系で再結晶させ、過、乾燥した。かくし
て得られたソルビン酸１ｇを１０mlのメタノールに溶解
した時の色価は、３５０μｍの波長における透過率を分
光々度計を用いて測定したところ、96.0％であり、ソル
ビン酸１ｇを１Ｎ−NaOH水溶液に溶解した時の色価は４
００μｍの波長における透過率で97.0％であった。Further, using a wet cake of sorbic acid, it was recrystallized in a methanol-water system according to a conventional method, dried and dried. When 1 g of the sorbic acid thus obtained was dissolved in 10 ml of methanol, the color value was 96.0% when the transmittance at a wavelength of 350 μm was measured using a spectrophotometer, and 1 g of sorbic acid was dissolved in 1N-NaOH. Color value when dissolved in aqueous solution is 4
The transmittance at a wavelength of 00 μm was 97.0%.
比較例１ 実施例１の方法に於て、溶解ＰＨ7.5とした以外同様の
処理を行なった。上層の溶解液は淡黄色であり、得られ
たソルビン酸湿ケーキも黄色を呈していた。Comparative Example 1 The same process as in Example 1 was carried out except that the dissolved pH was 7.5. The upper layer solution was pale yellow, and the obtained wet cake of sorbic acid was also yellow.
該ソルビン酸湿ケーキを用いて、メクタノール−水系で
再結晶させ過、乾燥を行なった。得られたソルビン酸
をメタノールに溶解した時の色価は92.0％であり、１Ｎ
−NaOH水溶液に溶解した時の色価は94.0％であった。The wet cake of sorbic acid was recrystallized in a mectanol-water system and dried. When the obtained sorbic acid was dissolved in methanol, the color value was 92.0%.
-The color number when dissolved in an aqueous NaOH solution was 94.0%.
比較例２ 実施例１と同様の粗ソルビン酸スラリーを６０℃の条件
で２５％NaOHを用いて溶解した。完溶するのにＰＨを6.
5迄上昇させなければならなかった他、ＰＨが5.5の時で
も溶解液の色は茶褐色を呈しており、底部に固いコーク
ス状のタールが沈殿していた。活性炭４ｇを用いて処理
し過しても、過液は淡黄色であり、得られたソルビ
ン酸湿ケーキも黄色を呈していた。Comparative Example 2 The same crude sorbic acid slurry as in Example 1 was dissolved using 25% NaOH at 60 ° C. PH to complete dissolution 6.
In addition to having to raise the pH to 5, even when the pH was 5.5, the color of the solution was dark brown, and hard coke-like tar was precipitated at the bottom. Even after the treatment with 4 g of activated carbon, the excess liquid was pale yellow and the obtained wet cake of sorbic acid was also yellow.
Claims (4)
られたポリエステルを分解し、得られたタール分を含む
粗ソルビン酸液を弱アルカリを用い、ｐＨを７以下で粗
ソルビン酸を溶解させる事を特徴とするソルビン酸の精
製方法。1. A method for decomposing a polyester obtained by a reaction between crotonaldehyde and ketene, and dissolving the obtained crude sorbic acid solution containing tar in a weak alkali with a pH of 7 or less to dissolve the crude sorbic acid. A method for purifying sorbic acid, which comprises:
不溶解タール分を分液除去することを特徴とする特許請
求の範囲第１項に記載の方法。2. After dissolving the crude sorbic acid with a weak alkali,
The method according to claim 1, wherein the insoluble tar component is separated and removed.
たって、温度を４０℃以上に保つことを特徴とする特許
請求の範囲第１項に記載の方法。3. The method according to claim 1, wherein in dissolving the crude sorbic acid with a weak alkali, the temperature is kept at 40 ° C. or higher.
ルカリがアルカリ土類金属の水酸化物あるいは酸化物、
アルカリ金属の重炭酸塩であることを特徴とする特許請
求の範囲第１項に記載の方法。4. A weak alkali used to dissolve crude sorbic acid is an alkaline earth metal hydroxide or oxide,
Process according to claim 1, characterized in that it is an alkali metal bicarbonate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61058093A JPH0653704B2 (en) | 1986-03-18 | 1986-03-18 | Method for purifying sorbic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61058093A JPH0653704B2 (en) | 1986-03-18 | 1986-03-18 | Method for purifying sorbic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62246539A JPS62246539A (en) | 1987-10-27 |
| JPH0653704B2 true JPH0653704B2 (en) | 1994-07-20 |
Family
ID=13074335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61058093A Expired - Fee Related JPH0653704B2 (en) | 1986-03-18 | 1986-03-18 | Method for purifying sorbic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0653704B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000103759A (en) * | 1998-09-29 | 2000-04-11 | Daicel Chem Ind Ltd | Production of sorbic acid or its salt |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2331668C2 (en) * | 1973-06-22 | 1982-07-29 | Hoechst Ag, 6000 Frankfurt | Process for purifying sorbic acid |
| JPS54103821A (en) * | 1978-01-17 | 1979-08-15 | Nippon Synthetic Chem Ind Co Ltd:The | Method of recovering sorbic acid from its dilute solution |
-
1986
- 1986-03-18 JP JP61058093A patent/JPH0653704B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62246539A (en) | 1987-10-27 |
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