JPH0336824B2 - - Google Patents
Info
- Publication number
- JPH0336824B2 JPH0336824B2 JP28920685A JP28920685A JPH0336824B2 JP H0336824 B2 JPH0336824 B2 JP H0336824B2 JP 28920685 A JP28920685 A JP 28920685A JP 28920685 A JP28920685 A JP 28920685A JP H0336824 B2 JPH0336824 B2 JP H0336824B2
- Authority
- JP
- Japan
- Prior art keywords
- alkali metal
- acid
- metal salt
- sulfuric acid
- iminodiacetic acid
- 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.)
- Expired
Links
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 142
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 96
- NBZBKCUXIYYUSX-UHFFFAOYSA-N iminodiacetic acid Chemical compound OC(=O)CNCC(O)=O NBZBKCUXIYYUSX-UHFFFAOYSA-N 0.000 claims description 86
- -1 alkali metal salt Chemical class 0.000 claims description 77
- 229910052783 alkali metal Inorganic materials 0.000 claims description 76
- 235000006408 oxalic acid Nutrition 0.000 claims description 47
- 239000007864 aqueous solution Substances 0.000 claims description 37
- 239000012452 mother liquor Substances 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 13
- 230000001376 precipitating effect Effects 0.000 claims description 6
- 238000002425 crystallisation Methods 0.000 claims 1
- 230000008025 crystallization Effects 0.000 claims 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 24
- 238000011084 recovery Methods 0.000 description 15
- DHMQDGOQFOQNFH-UHFFFAOYSA-N Glycine Chemical compound NCC(O)=O DHMQDGOQFOQNFH-UHFFFAOYSA-N 0.000 description 14
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 14
- 229910052938 sodium sulfate Inorganic materials 0.000 description 14
- 235000011152 sodium sulphate Nutrition 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- ZNCPFRVNHGOPAG-UHFFFAOYSA-L sodium oxalate Chemical compound [Na+].[Na+].[O-]C(=O)C([O-])=O ZNCPFRVNHGOPAG-UHFFFAOYSA-L 0.000 description 9
- 229940039790 sodium oxalate Drugs 0.000 description 9
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 8
- HAXVIVNBOQIMTE-UHFFFAOYSA-L disodium;2-(carboxylatomethylamino)acetate Chemical compound [Na+].[Na+].[O-]C(=O)CNCC([O-])=O HAXVIVNBOQIMTE-UHFFFAOYSA-L 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 239000004471 Glycine Substances 0.000 description 7
- 239000013078 crystal Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- WUWHFEHKUQVYLF-UHFFFAOYSA-M sodium;2-aminoacetate Chemical compound [Na+].NCC([O-])=O WUWHFEHKUQVYLF-UHFFFAOYSA-M 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003905 agrochemical Substances 0.000 description 1
- 159000000009 barium salts Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- 239000013522 chelant Substances 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- FOCAUTSVDIKZOP-UHFFFAOYSA-N chloroacetic acid Chemical compound OC(=O)CCl FOCAUTSVDIKZOP-UHFFFAOYSA-N 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000006356 dehydrogenation reaction Methods 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000001640 fractional crystallisation Methods 0.000 description 1
- LTYRAPJYLUPLCI-UHFFFAOYSA-N glycolonitrile Chemical compound OCC#N LTYRAPJYLUPLCI-UHFFFAOYSA-N 0.000 description 1
- JMANVNJQNLATNU-UHFFFAOYSA-N glycolonitrile Natural products N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- MGFYIUFZLHCRTH-UHFFFAOYSA-N nitrilotriacetic acid Chemical compound OC(=O)CN(CC(O)=O)CC(O)=O MGFYIUFZLHCRTH-UHFFFAOYSA-N 0.000 description 1
- 229940039748 oxalate Drugs 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 159000000000 sodium salts Chemical group 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
Landscapes
- 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）
本発明はシユウ酸のアルカリ金属塩を含む主と
してイミノジ酢酸アルカリ金属塩からなる水溶液
よりシユウ酸および／またはシユウ酸のアルカリ
金属塩の含量の極めて少ないイミノジ酢酸を高収
率で回収する方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention aims at reducing the content of oxalic acid and/or alkali metal salts of oxalic acid to a much higher level than in an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. This invention relates to a method for recovering a small amount of iminodiacetic acid in high yield.
（従来の技術）
イミノジ酢酸はキレート剤、キレート樹脂原
料、染色助剤、洗剤用ビルダー等のキレート作用
を利用する用途だけでなく、医薬、農薬の原料と
しても有用な化合物である。(Prior Art) Iminodiacetic acid is a compound that is useful not only for uses that utilize its chelating action, such as chelating agents, raw materials for chelate resins, dyeing aids, and builders for detergents, but also as raw materials for medicines and agricultural chemicals.
従来、イミノジ酢酸は、グリシンとグリコロニ
トリルの反応、アンモニア、シアン化水素及びホ
ルムアルデヒドの反応、アンモニアとモノクロル
酢酸の反応により合成されていたが、これらの方
法ではイミノジ酢酸との分離が困難なニトリロト
リ酢酸の副生が避けられず、イミノジ酢酸を高純
度、高収率で得ることは困難であつた。 Conventionally, iminodiacetic acid has been synthesized by the reaction of glycine and glycolonitrile, the reaction of ammonia, hydrogen cyanide and formaldehyde, and the reaction of ammonia and monochloroacetic acid. By-products are unavoidable, and it has been difficult to obtain iminodiacetic acid with high purity and high yield.
このような点から、現在ジエタノールアミンの
アルカリ金属水酸化物存在下での脱水素あるいは
空気酸化によるニトリロトリ酢酸を含まないイミ
ノジ酢酸の合成法が注目されている。しかし、こ
の場合には副反応により毒性で問題のあるシユウ
酸が生成する。従つて、このような反応により得
られるイミノジ酢酸アルカリ金属塩水溶液からイ
ミノジ酢酸を高純度で回収しようとする場合、ま
ず硫酸、塩酸等の無機酸で中和し、生成する無機
塩が沈殿しない条件、すなわち極めて薄い濃度下
で分別しなければならない、その場合回収される
イミノジ酢酸は高純度で得られるが回収率が著し
く低くなり経済的でない。 From this point of view, a method of synthesizing iminodiacetic acid that does not contain nitrilotriacetic acid by dehydrogenating diethanolamine in the presence of an alkali metal hydroxide or air oxidation is currently attracting attention. However, in this case, oxalic acid, which is toxic and problematic, is produced due to side reactions. Therefore, when attempting to recover iminodiacetic acid in high purity from an aqueous solution of alkali metal salt of iminodiacetic acid obtained by such a reaction, it is first necessary to neutralize it with an inorganic acid such as sulfuric acid or hydrochloric acid, and to obtain conditions under which the resulting inorganic salt does not precipitate. That is, it must be fractionated at an extremely dilute concentration. In this case, the recovered iminodiacetic acid can be obtained with high purity, but the recovery rate is extremely low and it is not economical.
また、シユウ酸をカルシウム塩、バリウム塩等
の沈殿剤を用いて、水不溶性の塩として除去する
方法はシユウ酸に対して大過剰量の沈殿剤が必要
となるばかりでなく、析出する沈殿中にはシユウ
酸塩だけでなく多量のイミノジ酢酸塩が含まれる
こととなり、回収率が低くしかも高純度のものが
得られないという欠点があつた。 In addition, the method of removing oxalic acid as a water-insoluble salt using a precipitant such as a calcium salt or barium salt not only requires a large excess amount of the precipitant relative to the oxalic acid, but also requires contains not only oxalate but also a large amount of iminodiacetate, resulting in a low recovery rate and the inability to obtain a highly pure product.
（発明が解決しようとする問題点）
本発明の目的は、上記問題点を解消するための
ものであり、より詳しくはシユウ酸のアルカリ金
属塩を含むイミノジ酢酸アルカリ金属塩水溶液よ
り、イミノジ酢酸を高純度に効率よく回収する方
法を提供することにある。(Problems to be Solved by the Invention) The purpose of the present invention is to solve the above-mentioned problems, and more specifically, to obtain iminodiacetic acid from an aqueous solution of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. The objective is to provide a method for efficiently recovering high purity.
（問題を解決するための手段および作用）
本発明は、シユウ酸のアルカリ金属塩を含む主
としてイミノジ酢酸アルカリ金属塩からなる水溶
液よりシユウ酸および／またはシユウ酸のアルカ
リ金属塩の含量の極めて少ないイミノジ酢酸を高
収率で回収する方法において、シユウ酸のアルカ
リ金属塩を含む主としてイミノジ酢酸アルカリ金
属塩からなる水溶液に硫酸および／または硫酸の
アルカリ金属塩水溶液を添加しPH3.5以上の条件
下イミノジ酢酸塩に対して25モル％以上に相当す
る硫酸のアルカリ金属塩を濃縮析出させ、硫酸の
アルカリ金属塩を除去した後、次いで該母液を硫
酸でPH2.0〜3.0とし、イミノジ酢酸を生成させこ
れを分別晶析することを特徴とするイミノジ酢酸
の回収方法に関するものである。(Means and Effects for Solving the Problems) The present invention provides an iminodiacetic acid solution having an extremely lower content of oxalic acid and/or an alkali metal salt of oxalic acid than an aqueous solution mainly consisting of an alkali metal salt of iminodiacetate containing an alkali metal salt of oxalic acid. In a method for recovering acetic acid with a high yield, sulfuric acid and/or an aqueous solution of an alkali metal salt of sulfuric acid is added to an aqueous solution consisting mainly of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid, and the iminodia is recovered under conditions of pH 3.5 or higher. After concentrating and precipitating the alkali metal salt of sulfuric acid corresponding to 25 mol% or more based on the acetate and removing the alkali metal salt of sulfuric acid, the mother liquor is then adjusted to pH 2.0 to 3.0 with sulfuric acid to generate iminodiacetic acid. The present invention relates to a method for recovering iminodiacetic acid, which is characterized by carrying out fractional crystallization of the iminodiacetic acid.
本発明はシユウ酸のアルカリ金属塩を含む主と
してイミノジ酢酸アルカリ金属塩からなる水溶液
よりシユウ酸および／またはシユウ酸のアルカリ
金属塩の含量の極めて少ないイミノジ酢酸を高収
率で回収する方法において、アルカリ金属塩がナ
トリウム塩または／およびカリウム塩である場合
特に有効である。 The present invention provides a method for recovering iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. It is particularly effective when the metal salt is a sodium salt or/and a potassium salt.
以下、本発明を説明する。 The present invention will be explained below.
ジエタノールアミンをアルカリ金属水酸化物の
存在下脱水素あるいは空気酸化すると、シユウ酸
のアルカリ金属塩がかなりの量生成するが、この
反応生成液系においてはシユウ酸のアルカリ金属
塩は過飽和状態で長期間安定に存在し、このまま
硫酸で中和しイミノジ酢酸を晶析させると、シユ
ウ酸がかなりの量不純物として含まれてしまう。 When diethanolamine is dehydrogenated or air oxidized in the presence of an alkali metal hydroxide, a considerable amount of alkali metal salts of oxalic acid are produced, but in this reaction product system, the alkali metal salts of oxalic acid remain in a supersaturated state for a long period of time. It exists stably, and if iminodiacetic acid is crystallized by neutralizing it with sulfuric acid, a considerable amount of oxalic acid will be included as an impurity.
本発明のシユウ酸のアルカリ金属塩を含む主と
してイミノジ酢酸アルカリ金属塩からなる水溶液
よりシユウ酸および／またはシユウ酸のアルカリ
金属塩の含量の極めて少ないイミノジ酢酸を高収
率で回収する方法において、シユウ酸のアルカリ
金属塩を含む主としてイミノジ酢酸アルカリ金属
塩からなる水溶液に硫酸あるいは硫酸のアルカリ
金属塩水溶液を添加し、その溶液のPHを3.5以上
に保つ必要がある。 In the method of recovering iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid according to the present invention, It is necessary to add sulfuric acid or an aqueous solution of an alkali metal salt of sulfuric acid to an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of an acid, and to maintain the pH of the solution at 3.5 or higher.
溶液のPHが3.5未満で硫酸のアルカリ金属塩を
析出させようとすると難溶性であるイミノジ酢酸
が析出する硫酸のアルカリ金属塩に混入するため
イミノジ酢酸の回収率が低くなる。これを防止す
るために水の除去量を少なくすると硫酸のアルカ
リ金属塩の析出量をイミノジ酢酸塩に対し25モル
％以上析出させることができないため、逆にシユ
ウ酸の除去が不充分となり高純度のイミノジ酢酸
は得られない。 If an attempt is made to precipitate an alkali metal salt of sulfuric acid when the pH of the solution is less than 3.5, the recovery rate of iminodiacetic acid will be low because poorly soluble iminodiacetic acid will be mixed with the precipitated alkali metal salt of sulfuric acid. To prevent this, if the amount of water removed is reduced, the amount of alkali metal salt of sulfuric acid that is precipitated cannot exceed 25 mol% relative to iminodiacetate, and conversely, the removal of oxalic acid becomes insufficient, resulting in high purity. iminodiacetic acid cannot be obtained.
本発明のシユウ酸のアルカリ金属塩を含む主と
してイミノジ酢酸アルカリ金属塩からなる水溶液
よりシユウ酸および／またはシユウ酸のアルカリ
金属塩の含量の極めて少ないイミノジ酢酸を高収
率で回収する方法において、シユウ酸のアルカリ
金属塩を含む主としてイミノジ酢酸アルカリ金属
塩からなる水溶液に硫酸あるいは硫酸のアルカリ
金属塩水溶液を添加しPH3.5以上の条件下、イミ
ノジ酢酸塩に対して25モル％以上、好ましくは30
モル％以上に相当する硫酸のアルカリ金属塩を濃
縮析出させることが必要である。 In the method of recovering iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid according to the present invention, Add sulfuric acid or an aqueous solution of an alkali metal salt of sulfuric acid to an aqueous solution containing an alkali metal salt of an acid, mainly consisting of an alkali metal salt of iminodiacetate, and under conditions of pH 3.5 or higher, 25 mol% or more, preferably 30% by mole based on the iminodiacetate.
It is necessary to concentrate and precipitate the alkali metal salt of sulfuric acid corresponding to mol% or more.
すなわちこのような系に硫酸あるいは硫酸のア
ルカリ金属塩水溶液を添加しPH3.5以上の条件下
イミノジ酢酸アルカリ金属塩に対して25モル％以
上に相当する硫酸ナトリウムを濃縮析出させるこ
とによりシユウ酸ナトリウムの過飽和状態は短期
間で解消される。 That is, by adding sulfuric acid or an aqueous solution of an alkali metal salt of sulfuric acid to such a system and concentrating and precipitating sodium sulfate equivalent to 25 mol% or more based on the alkali metal iminodiacetic acid salt under conditions of pH 3.5 or higher, sodium oxalate can be obtained. The supersaturation state will be resolved in a short period of time.
しかし、析出させる硫酸のアルカリ金属塩の量
がイミノジ酢酸アルカリ金属塩に対し25モル％よ
り低い場合にはシユウ酸のアルカリ金属塩の過飽
和状態はまだ充分に解消されず、このままで次の
イミノジ酢酸の析出の工程に移るとイミノジ酢酸
結晶中にシユウ酸および／またはシユウ酸のアル
カリ金属塩が混入し、目的とする高純度のイミノ
ジ酢酸は得られず、シユウ酸および／またはシユ
ウ酸のアルカリ金属塩の混入をさせないために
は、イミノジ酢酸析出時に多量の水や添加してや
らなければならず、結果としてイミノジ酢酸の回
収率が低くなる。 However, if the amount of the alkali metal salt of sulfuric acid to be precipitated is lower than 25 mol % based on the alkali metal salt of iminodiacetic acid, the supersaturation state of the alkali metal salt of oxalic acid is not sufficiently eliminated, and the next step is to proceed as it is. When moving to the precipitation step, oxalic acid and/or an alkali metal salt of oxalic acid are mixed into the iminodiacetic acid crystals, and the desired high-purity iminodiacetic acid cannot be obtained. In order to prevent salt from being mixed in, a large amount of water must be added during precipitation of iminodiacetic acid, resulting in a low recovery rate of iminodiacetic acid.
本発明において析出した硫酸およびシユウ酸の
アルカリ金属塩等の除去は通常の方法たとえば
過、遠心分離、デカンター等により行なうことが
できる。本発明のシユウ酸のアルカリ金属塩を含
む主としてイミノジ酢酸アルカリ金属塩からなる
水溶液よりシユウ酸および／またはシユウ酸のア
ルカリ金属塩の含量の極めて少ないイミノジ酢酸
を高収率で回収する方法において、シユウ酸のア
ルカリ金属塩を含む主としてイミノジ酢酸アルカ
リ金属塩からなる水溶液に硫酸あるいは硫酸のア
ルカリ金属塩水溶液を添加しPH3.5以上の条件下、
イミノジ酢酸塩に対して25モル％以上に相当する
硫酸のアルカリ金属塩を濃縮析出させ、硫酸のア
ルカリ金属塩を除去した後、次いで該母液を硫酸
でPH2.0〜3.0にすることが必要である。 In the present invention, the precipitated alkali metal salts of sulfuric acid and oxalic acid can be removed by conventional methods such as filtration, centrifugation, and decanting. In the method of recovering iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid according to the present invention, Add sulfuric acid or an aqueous solution of an alkali metal salt of sulfuric acid to an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of an acid, and under conditions of pH 3.5 or higher,
After concentrating and precipitating the alkali metal salt of sulfuric acid equivalent to 25 mol% or more based on the iminodiacetate and removing the alkali metal salt of sulfuric acid, it is necessary to adjust the mother liquor to pH 2.0 to 3.0 with sulfuric acid. be.
この操作によりシユウ酸および硫酸のアルカリ
金属塩のこの水溶液系における溶解度は増大する
ため析出するイミノジ酢酸は高純度のものとな
る。析出したイミノジ酢酸は同様に過、遠心分
離、デカンター等により容易に分離することがで
きる。 This operation increases the solubility of the alkali metal salts of oxalic acid and sulfuric acid in this aqueous solution system, so that the precipitated iminodiacetic acid becomes highly pure. The precipitated iminodiacetic acid can be easily separated by filtration, centrifugation, decanter, etc.
この際PHが3.0より高いとイミノジ酢酸の回収
率が低くなり、PHが2.0よりも低いとこの場合に
もイミノジ酢酸の回収率が悪くなり、しかも製品
乾燥時に着色等の問題が起こることがある。 In this case, if the pH is higher than 3.0, the recovery rate of iminodiacetic acid will be low, and if the pH is lower than 2.0, the recovery rate of iminodiacetic acid will be poor in this case as well, and problems such as coloring may occur during product drying. .
イミノジ酢酸を分離した上記母液はそのまま廃
棄してもよいが、イミノジ酢酸の回収率をさらに
向上させるためには全量あるいは一部を再循環し
て使用するのが望ましい。 The mother liquor from which iminodiacetic acid has been separated may be disposed of as is, but in order to further improve the recovery rate of iminodiacetic acid, it is desirable to recycle all or a portion of the mother liquor for use.
なお、本発明においてはジエタノールアミンの
脱水素あるいは酸化反応で混入する不純物例えば
ジエタノールアミン中の不純物のモノエタノール
アミンあるいは副反応に起因するグリシンはイミ
ノジ酢酸の回収率およびイミノジ酢酸の純度に何
ら悪影響を及ぼさない。なぜならグリシンはPH
2.0〜3.0というイミノジ酢酸析出条件ではイミノ
ジ酢酸に比べ非常に大きな溶解度であり、母液中
に残留するからである。 In addition, in the present invention, impurities mixed in during the dehydrogenation or oxidation reaction of diethanolamine, such as monoethanolamine as an impurity in diethanolamine, or glycine resulting from side reactions do not have any adverse effect on the recovery rate of iminodiacetic acid and the purity of iminodiacetic acid. . Because glycine has a PH
This is because under the precipitation conditions of iminodiacetic acid of 2.0 to 3.0, it has a much higher solubility than iminodiacetic acid and remains in the mother liquor.
（作用）
本発明は、シユウ酸のアルカリ金属塩を含む主
としてイミノジ酢酸アルカリ金属塩からなる水溶
液よりシユウ酸および／またはシユウ酸のアルカ
リ金属塩の含量の極めて少ないイミノジ酢酸を高
収率で回収する方法において、シユウ酸のアルカ
リ金属塩を含む主としてイミノジ酢酸アルカリ金
属塩からなる水溶液に硫酸あるいは硫酸のアルカ
リ金属塩水溶液を添加しPH3.5以上の条件下イミ
ノジ酢酸塩に対して25モル％以上に相当する硫酸
のアルカリ金属塩を濃縮析出させ、硫酸のアルカ
リ金属塩を除去した後、次いで該母液を硫酸でPH
2.0〜3.0とすることにより、イミノジ酢酸を高純
度に効率よく回収する作用を提供できるものであ
る。(Function) The present invention recovers iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. In the method, sulfuric acid or an aqueous solution of an alkali metal salt of sulfuric acid is added to an aqueous solution mainly consisting of an alkali metal salt of iminodiacetate containing an alkali metal salt of oxalic acid, and the concentration is 25 mol% or more based on the iminodiacetate under a pH of 3.5 or higher. After concentrating and precipitating the corresponding alkali metal salt of sulfuric acid and removing the alkali metal salt of sulfuric acid, the mother liquor was then PHed with sulfuric acid.
By setting it to 2.0 to 3.0, it is possible to provide the effect of efficiently recovering iminodiacetic acid with high purity.
（実施例）
以下、実施例を挙げて、本発明の実施の態様を
具体的に例示して説明する。本発明はこれらの実
施例に限定されるものではない。(Example) Hereinafter, embodiments of the present invention will be specifically illustrated and described with reference to Examples. The present invention is not limited to these examples.
実施例 １
ジエタノールアミンを水酸化ナトリウムの存在
下脱水素し、イミノジ酢酸二ナトリウム20.1重量
％、シユウ酸ナトリウム0.4重量％、グリシンナ
トリウム0.3重量％、水酸化ナトリウム0.4重量％
の組成の水溶液が得られた。Example 1 Diethanolamine was dehydrogenated in the presence of sodium hydroxide, resulting in 20.1% by weight of disodium iminodiacetate, 0.4% by weight of sodium oxalate, 0.3% by weight of sodium glycine, and 0.4% by weight of sodium hydroxide.
An aqueous solution having the composition was obtained.
この水溶液2000ｇに98重量％硫酸126ｇを加え
PHを6.4とした。この溶液から減圧下加熱し水を
1336ｇ除去し、80℃以上で析出した硫酸ナトリウ
ムを遠心分離した。この際析出した硫酸ナトリウ
ムの量は150ｇであり、イミノジ酢酸ナトリウム
に対し43モル％であつた。また、母液中のシユウ
酸ナトリウム濃度は0.07重量％であつた。さらに
この母液に水100ｇを添加した後98重量％硫酸114
ｇでPH2.4とした。この液を40℃まで冷却し析出
したイミノジ酢酸を遠心分離した後イミノジ酢酸
の結晶を水洗した。結晶を110℃３時間乾燥し254
ｇのイミノジ酢酸を得た。このイミノジ酢酸中の
硫酸ナトリウムは0.05重量％であり、シユウ酸及
びグリシンは検出されなかつた。 Add 126g of 98% sulfuric acid to 2000g of this aqueous solution.
The pH was set to 6.4. Heat water under reduced pressure from this solution.
1336g was removed and the sodium sulfate precipitated at 80°C or higher was centrifuged. The amount of sodium sulfate precipitated at this time was 150 g, which was 43 mol % based on sodium iminodiacetate. Moreover, the sodium oxalate concentration in the mother liquor was 0.07% by weight. Furthermore, after adding 100 g of water to this mother liquor, 98 wt% sulfuric acid 114
g to set the pH to 2.4. This solution was cooled to 40°C, the precipitated iminodiacetic acid was centrifuged, and the iminodiacetic acid crystals were washed with water. Dry the crystals at 110℃ for 3 hours.
g of iminodiacetic acid was obtained. Sodium sulfate in this iminodiacetic acid was 0.05% by weight, and oxalic acid and glycine were not detected.
イミノジ酢酸の回収率は84.1モル％であつた。 The recovery rate of iminodiacetic acid was 84.1 mol%.
実施例 ２
ジエタノールアミンを水酸化ナトリウムの存在
下脱水素し、イミノジ酢酸二ナトリウム20.1重量
％、シユウ酸ナトリウム0.4重量％、グリシンナ
トリウム0.3重量％、水酸化ナトリウム0.4重量％
の組成の水溶液が得られた。Example 2 Diethanolamine was dehydrogenated in the presence of sodium hydroxide to produce 20.1% by weight of disodium iminodiacetate, 0.4% by weight of sodium oxalate, 0.3% by weight of sodium glycine, and 0.4% by weight of sodium hydroxide.
An aqueous solution having the composition was obtained.
この水溶液2000ｇに実施例１で得られたイミノ
ジ酢酸回収後の母液700ｇを加えた。 To 2000 g of this aqueous solution was added 700 g of the mother liquor obtained in Example 1 after recovery of iminodiacetic acid.
この母液中にはイミノジ酢酸が31ｇ、硫酸ナト
リウムが178ｇ含まれていた。 This mother liquor contained 31 g of iminodiacetic acid and 178 g of sodium sulfate.
以下この液を用い実施例１と同様の操作を行な
い、290ｇの硫酸ナトリウムすなわちイミノジ酢
酸ナトリウムに対し82モル％を析出した。この母
液中のシユウ酸ナトリウム濃度は0.06重量％であ
つた。以下同様の操作を行ない、286ｇのイミノ
ジ酢酸を得た。このイミノジ酢酸中の硫酸ナトリ
ウムは0.05重量％であり、シユウ酸及びグリシン
は検出されなかつた。 Thereafter, the same operation as in Example 1 was carried out using this liquid, and 82 mol % was precipitated based on 290 g of sodium sulfate, that is, sodium iminodiacetate. The sodium oxalate concentration in this mother liquor was 0.06% by weight. The same operation was carried out thereafter to obtain 286 g of iminodiacetic acid. Sodium sulfate in this iminodiacetic acid was 0.05% by weight, and oxalic acid and glycine were not detected.
イミノジ酢酸の回収率は新たに供給したイミノ
ジ酢酸を基準として94.7モル％であつた。 The recovery rate of iminodiacetic acid was 94.7 mol% based on the freshly supplied iminodiacetic acid.
実施例 ３
ジエタノールアミンを水酸化ナトリウムの存在
下脱水素し、イミノジ酢酸二ナトリウム20.1重量
％、シユウ酸ナトリウム0.4重量％、グリシンナ
トリウム0.3重量％、水酸化ナトリウム0.4重量％
の組成の水溶液が得られた。この水溶液2000ｇに
硫酸ナトリウム140ｇを含む水溶液500ｇを加え
た。Example 3 Diethanolamine was dehydrogenated in the presence of sodium hydroxide, resulting in 20.1% by weight of disodium iminodiacetate, 0.4% by weight of sodium oxalate, 0.3% by weight of sodium glycine, and 0.4% by weight of sodium hydroxide.
An aqueous solution having the composition was obtained. 500 g of an aqueous solution containing 140 g of sodium sulfate was added to 2000 g of this aqueous solution.
この溶液から水1590ｇをを除去し80℃以上で析
出した硫酸ナトリウムを遠心分離した。この際析
出した硫酸ナトリウムの量は93ｇであり、イミノ
ジ酢酸ナトリウムに対し29モル％であつた。また
母液中のシユウ酸ナトリウム濃度は0.10重量％で
あつた。 1590 g of water was removed from this solution, and the sodium sulfate precipitated at 80°C or higher was centrifuged. The amount of sodium sulfate precipitated at this time was 93 g, which was 29 mol % based on sodium iminodiacetate. The concentration of sodium oxalate in the mother liquor was 0.10% by weight.
さらにこの母液に水510ｇを添加した後98重量
％硫酸240ｇでPH2.4にした。この液を40℃まで冷
却し析出したイミノジ酢酸を遠心分離した後、イ
ミノジ酢酸の結晶を水洗した。結晶を110℃３時
間乾燥し202ｇのイミノジ酢酸を得た。このイミ
ノジ酢酸中の硫酸ナトリウムは0.08重量％であ
り、シユウ酸及びグリシンは検出されなかつた。 Furthermore, 510 g of water was added to this mother liquor, and the pH was adjusted to 2.4 with 240 g of 98% sulfuric acid. This liquid was cooled to 40° C., and the precipitated iminodiacetic acid was centrifuged, and then the iminodiacetic acid crystals were washed with water. The crystals were dried at 110° C. for 3 hours to obtain 202 g of iminodiacetic acid. Sodium sulfate in this iminodiacetic acid was 0.08% by weight, and oxalic acid and glycine were not detected.
イミノジ酢酸の回収率は66.9モル％であつた。 The recovery rate of iminodiacetic acid was 66.9 mol%.
比較例 １
ジエタノールアミンを水酸化ナトリウムの存在
下脱水素し、イミノジ酢酸二ナトリウム20.1重量
％、シユウ酸ナトリウム0.4重量％、グリシンナ
トリウム0.3重量％、水酸化ナトリウム0.4重量％
の組成の水溶液が得られた。Comparative Example 1 Diethanolamine was dehydrogenated in the presence of sodium hydroxide, resulting in 20.1% by weight of disodium iminodiacetate, 0.4% by weight of sodium oxalate, 0.3% by weight of sodium glycine, and 0.4% by weight of sodium hydroxide.
An aqueous solution having the composition was obtained.
この水溶液2000ｇに98重量％硫酸126ｇを加え
PHを6.4とした。この溶液から減圧下加熱し水を
590ｇ除去し、80℃以上で析出した硫酸ナトリウ
ムを遠心分離した。この際析出した硫酸ナトリウ
ムの量は61ｇであり、イミノジ酢酸ナトリウムに
対し19モル％であつた。また、母液中のシユウ酸
ナトリウム濃度は0.19重量％であつた。 Add 126g of 98% sulfuric acid to 2000g of this aqueous solution.
The pH was set to 6.4. Heat water under reduced pressure from this solution.
590g was removed and the sodium sulfate precipitated at 80°C or higher was centrifuged. The amount of sodium sulfate precipitated at this time was 61 g, which was 19 mol % based on sodium iminodiacetate. Moreover, the sodium oxalate concentration in the mother liquor was 0.19% by weight.
さらにこの母液に水500ｇを添加した後、98重
量％硫酸114ｇでPH2.4とした。この液を40℃まで
冷却し析出したイミノジ酢酸を遠心分離した後、
イミノジ酢酸の結晶を水洗した。結晶を110℃３
時間乾燥し162ｇのイミノジ酢酸を得た。このイ
ミノジ酢酸中の硫酸ナトリウムは0.06重量％であ
り、シユウ酸及びグリシンは検出されなかつた。 Furthermore, after adding 500 g of water to this mother liquor, the pH was adjusted to 2.4 with 114 g of 98% sulfuric acid. After cooling this solution to 40℃ and centrifuging the precipitated iminodiacetic acid,
The iminodiacetic acid crystals were washed with water. Crystals at 110℃3
After drying for hours, 162 g of iminodiacetic acid was obtained. Sodium sulfate in this iminodiacetic acid was 0.06% by weight, and oxalic acid and glycine were not detected.
イミノジ酢酸の回収率は54モル％であつた。 The recovery rate of iminodiacetic acid was 54 mol%.
（発明の効果）
本発明は、シユウ酸のアルカリ金属塩を含む主
としてイミノジ酢酸アルカリ金属塩からなる水溶
液よりシユウ酸および／またはシユウ酸のアルカ
リ金属塩の含量の極めて少ないイミノジ酢酸を高
収率で回収する方法において、シユウ酸のアルカ
リ金属塩を含む主としてイミノジ酢酸アルカリ金
属塩からなる水溶液に硫酸および／または硫酸の
アルカリ金属塩水溶液を添加しPH3.5以上の条件
下イミノジ酢酸塩に対して25モル％以上に相当す
る硫酸のアルカリ金属塩を濃縮析出させ、硫酸の
アルカリ金属塩を除去した後、次いで該母液を硫
酸でPH2.0〜3.0とすることにより、イミノジ酢酸
を高純度に効率よく回収する効果を提供できるも
のである。(Effects of the Invention) The present invention can produce iminodiacetic acid with an extremely low content of oxalic acid and/or an alkali metal salt of oxalic acid in a higher yield than an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. In the recovery method, sulfuric acid and/or an aqueous solution of an alkali metal salt of sulfuric acid is added to an aqueous solution mainly consisting of an alkali metal salt of iminodiacetate containing an alkali metal salt of oxalic acid, and 25 After concentrating and precipitating the alkali metal salt of sulfuric acid equivalent to more than mol% and removing the alkali metal salt of sulfuric acid, the mother liquor is then adjusted to pH 2.0 to 3.0 with sulfuric acid to efficiently produce iminodiacetic acid with high purity. It can provide the effect of recovery.
Claims (1)
ミノジ酢酸アルカリ金属塩からなる水溶液よりシ
ユウ酸および／またはシユウ酸のアルカリ金属塩
の含量の極めて少ないイミノジ酢酸を高収率で回
収する方法において、シユウ酸のアルカリ金属塩
を含む主としてイミノジ酢酸アルカリ金属塩から
なる水溶液に硫酸および／または硫酸のアルカリ
金属塩水溶液を添加しPH3.5以上の条件下、イミ
ノジ酢酸塩に対して25モル％以上に相当する硫酸
のアルカリ金属塩を濃縮析出させ、硫酸のアルカ
リ金属塩を除去した後、次いで該母液を硫酸でPH
2.0〜3.0とし、イミノジ酢酸を生成させ分別晶析
することを特徴とするイミノジ酢酸の回収方法。1. A method for recovering iminodiacetic acid with a very low content of oxalic acid and/or an alkali metal salt of oxalic acid in a high yield from an aqueous solution mainly consisting of an alkali metal salt of iminodiacetic acid containing an alkali metal salt of oxalic acid. Adding sulfuric acid and/or an aqueous solution of an alkali metal salt of sulfuric acid to an aqueous solution mainly consisting of an alkali metal salt of iminodiacetate containing an alkali metal salt, and adding sulfuric acid and/or an aqueous solution of an alkali metal salt of sulfuric acid to a pH of 3.5 or higher, produces sulfuric acid equivalent to 25 mol% or more based on the iminodiacetate. After concentrating and precipitating the alkali metal salts of sulfuric acid and removing the alkali metal salts of sulfuric acid, the mother liquor was PHed with sulfuric acid.
2.0 to 3.0, and is characterized by producing iminodiacetic acid and performing separate crystallization.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28920685A JPS62148456A (en) | 1985-12-24 | 1985-12-24 | Recovery of iminodiacetic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28920685A JPS62148456A (en) | 1985-12-24 | 1985-12-24 | Recovery of iminodiacetic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62148456A JPS62148456A (en) | 1987-07-02 |
| JPH0336824B2 true JPH0336824B2 (en) | 1991-06-03 |
Family
ID=17740149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28920685A Granted JPS62148456A (en) | 1985-12-24 | 1985-12-24 | Recovery of iminodiacetic acid |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62148456A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10187314B2 (en) * | 2015-05-22 | 2019-01-22 | Qualcomm Incorporated | Techniques for signal extension signaling |
-
1985
- 1985-12-24 JP JP28920685A patent/JPS62148456A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62148456A (en) | 1987-07-02 |
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