JPH10316410A - Production of lithium hexafluorophosphate - Google Patents

Production of lithium hexafluorophosphate

Info

Publication number
JPH10316410A
JPH10316410A JP9079827A JP7982797A JPH10316410A JP H10316410 A JPH10316410 A JP H10316410A JP 9079827 A JP9079827 A JP 9079827A JP 7982797 A JP7982797 A JP 7982797A JP H10316410 A JPH10316410 A JP H10316410A
Authority
JP
Japan
Prior art keywords
lithium hexafluorophosphate
dimethyl carbonate
lithium
solvent
crystal
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
Application number
JP9079827A
Other languages
Japanese (ja)
Other versions
JP3483099B2 (en
Inventor
Shoichi Tsujioka
辻岡  章一
Hisakazu Ito
久和 伊東
Mitsuo Takahata
満夫 高畑
Tadayuki Kawashima
忠幸 川島
Hiromi Sasaki
広美 佐々木
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Central Glass Co Ltd
Original Assignee
Central Glass Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Central Glass Co Ltd filed Critical Central Glass Co Ltd
Priority to JP07982797A priority Critical patent/JP3483099B2/en
Publication of JPH10316410A publication Critical patent/JPH10316410A/en
Application granted granted Critical
Publication of JP3483099B2 publication Critical patent/JP3483099B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Abstract

PROBLEM TO BE SOLVED: To provide a production process for lithium hexafluorophosphate of a high purity with excellent storage stability. SOLUTION: A solution of lithium hexafluorophosphate in dimethyl carbonate is concentrated by evaporation of the solvent in the temperature range from -20 to +150 deg.C to crystallize out lithium hexafluorophosphate with particle sizes of >=50 μm. Or, the crystals are dissolved again in dimethyl carbonate followed by recrystallization. The collected lithium hexafluorophosphate is dried in the temperature range of from -20 to +150 deg.C.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、リチウム電池およ
びリチウムイオン電池用電解質として有用なヘキサフル
オロリン酸リチウムの製造方法に関する。
The present invention relates to a method for producing lithium hexafluorophosphate useful as an electrolyte for lithium batteries and lithium ion batteries.

【0002】[0002]

【従来技術】ヘキサフルオロリン酸リチウムの製造方法
としては種々提案されており、例えば無溶媒で固体のフ
ッ化リチウムと気体の五フッ化リンを反応させる方法
(特開昭64−72901号)等がある。この方法にお
いては、フッ化リチウムの表面に反応生成物の被膜が形
成され、完全には反応が進行せず未反応のフッ化リチウ
ムが残存する。
2. Description of the Related Art Various methods for producing lithium hexafluorophosphate have been proposed, for example, a method of reacting solid lithium fluoride with gaseous phosphorus pentafluoride without a solvent (Japanese Patent Application Laid-Open No. Sho 64-72901). There is. In this method, a film of a reaction product is formed on the surface of lithium fluoride, and the reaction does not proceed completely, and unreacted lithium fluoride remains.

【0003】また、無水フッ化水素を溶媒として、溶解
したフッ化リチウムと気体状の五フッ化リンを反応させ
る方法(J.Chem.Soc.Part4,4408
(1963))がある。この方法においては、蒸気圧の
高い無水フッ化水素を溶媒として使用するため、ハンド
リングが困難であり、また、反応後に結晶として取り出
したヘキサフルオロリン酸リチウム中に不純物としてフ
ッ化水素が残存する。この不純物のフッ化水素はリチウ
ム電池として使用する場合、その電池反応を阻害するも
のであり、好ましくない。
Further, a method of reacting dissolved lithium fluoride with gaseous phosphorus pentafluoride using anhydrous hydrogen fluoride as a solvent (J. Chem. Soc. Part 4, 4408).
(1963)). In this method, since anhydrous hydrogen fluoride having a high vapor pressure is used as a solvent, handling is difficult, and hydrogen fluoride remains as an impurity in lithium hexafluorophosphate taken out as crystals after the reaction. When used as a lithium battery, this impurity, hydrogen fluoride, inhibits the battery reaction and is not preferred.

【0004】また、有機溶媒にヘキサフルオロリン酸リ
チウム溶解して再結晶することにより、不純物の除去を
行う方法もいくつか提案されているが、有機溶媒から結
晶化する際に、溶媒分子とヘキサフルオロリン酸リチウ
ム分子が付加物を形成し、得られた結晶はヘキサフルオ
ロリン酸リチウム・有機溶媒の付加物結晶となり、この
溶媒分子を減圧等で強制的に除去するとヘキサフルオロ
リン酸リチウムが、非常に表面積の大きい活性なものと
なり、分解が促進されるため、この方法も実用的ではな
い。 このように従来の方法においては、いずれも反応
収率、反応の制御のしやすさ、得られる製品の純度等の
点で必ずしも満足のできるものではなかった。
Several methods have been proposed for removing impurities by dissolving lithium hexafluorophosphate in an organic solvent and recrystallizing the same. The lithium fluorophosphate molecule forms an adduct, and the obtained crystal becomes an adduct crystal of lithium hexafluorophosphate / organic solvent. When the solvent molecule is forcibly removed under reduced pressure or the like, lithium hexafluorophosphate becomes This method is also impractical because it becomes active with a very large surface area and promotes decomposition. As described above, all of the conventional methods are not always satisfactory in terms of the reaction yield, the ease of controlling the reaction, the purity of the obtained product, and the like.

【0005】[0005]

【問題点を解決するための具体的手段】本発明者らは、
かかる従来技術の問題点に鑑み鋭意検討の結果、ジメチ
ルカーボネート中で製造することにより、不純物の少な
いヘキサフルオロリン酸リチウムができることを見いだ
し、本発明に到達したものである。
[Specific means for solving the problem]
As a result of diligent studies in view of the problems of the prior art, the present inventors have found that lithium hexafluorophosphate with few impurities can be produced by producing in dimethyl carbonate, and have reached the present invention.

【0006】すなわち本発明は、ジメチルカーボネート
中でフッ化リチウムと五フッ化リンとを反応させること
により得られるヘキサフルオロリン酸リチウムをジメチ
ルカーボネート溶液中より、−20℃から150℃の温
度範囲でジメチルカーボネートを蒸発させ、溶液を濃縮
する方法により、50μm以上の粒径のヘキサフルオロ
リン酸リチウム結晶を晶出させるものであり、またヘキ
サフルオロリン酸リチウムをジメチルカーボネート中に
溶解し、−20℃から150℃の温度範囲で蒸発濃縮に
より再結晶し、粒径が50μm以上の結晶を得るもの
で、さらに得られた結晶を−20℃から150℃の温度
範囲で乾燥することを特徴とするヘキサフルオロリン酸
リチウムの製造方法を提供するものである。
That is, according to the present invention, lithium hexafluorophosphate obtained by reacting lithium fluoride and phosphorus pentafluoride in dimethyl carbonate is prepared from a dimethyl carbonate solution at a temperature in the range of -20 ° C to 150 ° C. Dimethyl carbonate is evaporated to crystallize lithium hexafluorophosphate crystals having a particle diameter of 50 μm or more by a method of concentrating the solution. Lithium hexafluorophosphate is dissolved in dimethyl carbonate, and the solution is dissolved at −20 ° C. Recrystallize by evaporating and concentrating at a temperature in the range of from −150 ° C. to obtain crystals having a particle size of 50 μm or more, and further drying the obtained crystals in a temperature range from −20 ° C. to 150 ° C. It is intended to provide a method for producing lithium fluorophosphate.

【0007】本発明の製造方法は、反応収率が高く、反
応の制御も容易で、製品の純度、結晶の性状の点でも十
分満足できるものである。本発明において、問題となっ
ているヘキサフルオロリン酸リチウム中の不純物である
フッ化水素は、従来の方法では、反応溶媒として使用す
る無水フッ化水素から来ることは明らかである。そこ
で、溶媒として他の有機溶媒を使用することが有効であ
る。有機溶媒から一般的な方法で、結晶を晶出する場合
は、ヘキサフルオロリン酸リチウムと溶媒の相互作用が
強いため、ヘキサフルオロリン酸リチウム1分子に対し
て、溶媒が1から6分子程度配位した状態で付加物結晶
を形成するので、純粋なヘキサフルオロリン酸リチウム
を得るためには、真空乾燥を行い付加した溶媒分子を除
去する必要がある。しかし、一旦付加物結晶になったも
のから、溶媒分子のみを除去するためには、多大な労力
と時間を要するため好ましい方法とは思われない。しか
も、溶媒分子を除去した後の結晶は、表面がポーラス
で、粒径も10μm以下の微細な凝集晶となり、表面の
活性があがることにより、保存中に熱による自己分解
(例えば、LiPF6→LiF+PF5)や雰囲気中のわ
ずかな水分による加水分解(例えば、LiPF6+2H2
O→LiPO22 + 4HF)が起こるという新たな
問題が発生する。このようなことにより、有機溶媒から
のヘキサフルオロリン酸リチウムの晶出は非常に困難で
あると考えられていた。
The production method of the present invention has a high reaction yield, easy control of the reaction, and is satisfactory in terms of product purity and crystal properties. In the present invention, it is apparent that hydrogen fluoride, which is an impurity in lithium hexafluorophosphate, which is a problem, comes from anhydrous hydrogen fluoride used as a reaction solvent in the conventional method. Therefore, it is effective to use another organic solvent as the solvent. When a crystal is crystallized from an organic solvent by a general method, since the interaction between lithium hexafluorophosphate and the solvent is strong, about 1 to 6 molecules of the solvent are distributed per 1 molecule of lithium hexafluorophosphate. Since an adduct crystal is formed in the aligned state, in order to obtain pure lithium hexafluorophosphate, it is necessary to remove the added solvent molecules by vacuum drying. However, it is not considered to be a preferable method because it takes a great deal of labor and time to remove only the solvent molecules from the crystal once formed into the adduct. Moreover, crystals after removal of the solvent molecules, the surface a porous, the particle size becomes less fine aggregate crystals 10 [mu] m, by the activity of the surface is increased, the thermal self-decomposition by during storage (e.g., LiPF 6 → (LiF + PF 5 ) or hydrolysis by slight moisture in the atmosphere (for example, LiPF 6 + 2H 2).
O → LiPO 2 F 2 + 4HF) occurs. For these reasons, it has been considered that crystallization of lithium hexafluorophosphate from an organic solvent is extremely difficult.

【0008】そこで、本発明者らが種々検討した結果、
有機非水溶媒からヘキサフルオロリン酸リチウムの結晶
を晶出する場合、20℃以上の温度領域で蒸発濃縮にて
晶出することにより、結晶の相転移が起こり、付加物で
はない純粋なヘキサフルオロリン酸リチウムの結晶が得
られることを見出し、既に特許出願をしている。
Therefore, as a result of various studies by the present inventors,
When crystal of lithium hexafluorophosphate is crystallized from an organic non-aqueous solvent, by crystallizing by evaporating and concentrating in a temperature range of 20 ° C. or more, phase transition of the crystal occurs, and pure hexafluorophosphate which is not an adduct is produced. They have found that lithium phosphate crystals can be obtained, and have already filed a patent application.

【0009】しかし、さらに検討を進めていく中で、ジ
メチルカーボネートのみが特異的に20℃より低い温度
領域においても、付加物結晶を形成しないことを見いだ
したものである。
However, during further study, they have found that only dimethyl carbonate does not specifically form adduct crystals even in a temperature range lower than 20 ° C.

【0010】本発明の製造方法は、このジメチルカーボ
ネートの特異性を利用したものであり、このジメチルカ
ーボネートを溶媒として使用すれば、他の溶媒のように
シビアな温度コントロールする必要もなく、効率的にヘ
キサフルオロリン酸リチウムを製造することが可能とな
る。
The production method of the present invention utilizes the specificity of this dimethyl carbonate. If this dimethyl carbonate is used as a solvent, it is not necessary to control the temperature as severe as other solvents, and it is efficient. To produce lithium hexafluorophosphate.

【0011】本発明の製造方法では、ジメチルカーボネ
ート中で、ヘキサフルオロリン酸リチウムの合成を行
う。上記溶媒中に原料であるフッ化リチウムの溶解度は
非常に小さいため、溶媒に分散した状態で五フッ化リン
のガスを吹き込み反応を行う。ここで、生成したヘキサ
フルオロリン酸リチウムは非常に溶解度が大きいので、
溶媒中に溶解して、表面に被膜として残ることがないた
めに反応は完全に進行する。
In the production method of the present invention, lithium hexafluorophosphate is synthesized in dimethyl carbonate. Since the solubility of lithium fluoride as a raw material in the solvent is very small, a gas of phosphorus pentafluoride is blown in a state of being dispersed in the solvent to perform a reaction. Here, the generated lithium hexafluorophosphate has a very high solubility,
The reaction proceeds completely because it does not dissolve in the solvent and remains as a film on the surface.

【0012】この反応を行う際の温度は、下限が−40
℃、好ましくは0℃で、上限は100℃、好ましくは6
0℃である。反応温度が−40℃未満では、溶媒が凝固
するため反応が進行しない。また、100℃より大きい
場合、溶媒と五フッ化リンの反応が起こり、着色や粘度
増加の原因となるため好ましくない。
The temperature at which this reaction is carried out has a lower limit of -40.
℃, preferably 0 ℃, the upper limit is 100 ℃, preferably 6 ℃
0 ° C. If the reaction temperature is lower than −40 ° C., the reaction does not proceed because the solvent solidifies. On the other hand, if the temperature is higher than 100 ° C., a reaction between the solvent and phosphorus pentafluoride occurs, which causes coloring and an increase in viscosity, which is not preferable.

【0013】フッ化リチウムの量は、溶媒1リットルに
対して、200g以下、好ましくは100g以下であ
る。フッ化リチウムの量が溶媒に対して、200gより
多い場合は生成物が飽和になり、フッ化リチウム表面に
被膜が生成し、未反応のフッ化リチウムが残存するうえ
に溶液の粘度が上昇するため、濾過等の分離操作が困難
になる。 五フッ化リンの量は、フッ化リチウムに対し
て当量以上あれば良いが、過剰に系内に導入した場合、
溶液中に吸収されるため、反応後に加熱、減圧等の操作
により除去する必要がある。
The amount of lithium fluoride is 200 g or less, preferably 100 g or less, per liter of the solvent. If the amount of lithium fluoride is more than 200 g with respect to the solvent, the product becomes saturated, a film is formed on the surface of lithium fluoride, unreacted lithium fluoride remains, and the viscosity of the solution increases. Therefore, separation operation such as filtration becomes difficult. The amount of phosphorus pentafluoride may be at least equivalent to lithium fluoride, but when introduced into the system in excess,
Since it is absorbed in the solution, it needs to be removed after the reaction by an operation such as heating or depressurization.

【0014】この反応において、原料の五フッ化リン、
および生成物のヘキサフルオロリン酸リチウムは、水分
により容易に加水分解を受けるので、水分を含まない雰
囲気で反応を実施する必要がある。すなわち、真空中や
窒素等の不活性ガス雰囲気中で反応を行うことが好まし
い。
In this reaction, the raw material phosphorus pentafluoride,
Since the product lithium hexafluorophosphate is easily hydrolyzed by water, it is necessary to carry out the reaction in an atmosphere containing no water. That is, the reaction is preferably performed in a vacuum or an inert gas atmosphere such as nitrogen.

【0015】得られたヘキサフルオロリン酸リチウムの
溶液を適当な方法で精製した後、晶析操作を行い、結晶
を取り出す。また、本発明において、従来の方法で製造
したヘキサフルオロリン酸リチウム結晶をジメチルカー
ボネート中に溶解した後、晶析操作を行い再結晶化す
る。ここで、再結晶だけでも十分ではあるが、溶液の段
階で適当な方法により、フッ化水素その他の不純物の精
製をさらに行えばより効果的である。
After the obtained solution of lithium hexafluorophosphate is purified by an appropriate method, a crystallization operation is performed to take out crystals. Further, in the present invention, after dissolving lithium hexafluorophosphate crystals produced by a conventional method in dimethyl carbonate, recrystallization is performed by performing a crystallization operation. Here, although recrystallization alone is sufficient, it is more effective to further purify hydrogen fluoride and other impurities by a suitable method at the solution stage.

【0016】本発明の製造方法において、ポイントとな
るのはジメチルカーボネートを溶媒として使用して、ヘ
キサフルオロリン酸リチウム結晶を晶出させることであ
る。ジメチルカーボネートとヘキサフルオロリン酸リチ
ウムの系では、他の溶媒と異なり共晶点が−20℃であ
るため、晶析の温度範囲は下限が−20℃、好ましくは
−10℃で、上限は150℃、好ましくは90℃であ
る。この温度が−20℃未満ではヘキサフルオロリン酸
リチウムとジメチルカーボネートの付加物結晶となるた
め好ましくない。また、150℃より高い温度ではヘキ
サフルオロリン酸リチウムの分解、溶媒との反応が起こ
るため好ましくない。
In the production method of the present invention, the point is to crystallize lithium hexafluorophosphate crystals using dimethyl carbonate as a solvent. In the system of dimethyl carbonate and lithium hexafluorophosphate, unlike other solvents, the eutectic point is −20 ° C., so the lower limit of the crystallization temperature range is −20 ° C., preferably −10 ° C., and the upper limit is 150 ° C. ° C, preferably 90 ° C. If this temperature is lower than -20 ° C, an adduct of lithium hexafluorophosphate and dimethyl carbonate is formed, which is not preferable. On the other hand, if the temperature is higher than 150 ° C., decomposition of lithium hexafluorophosphate and reaction with a solvent occur, which is not preferable.

【0017】晶析の手段は、この温度領域では溶解度の
温度依存性が小さくなるため蒸発濃縮により、結晶を晶
出する方法が好ましい。結晶の晶出後、ろ過により固液
分離するが、結晶表面に付着した溶液が室温に戻るとジ
メチルカーボネート以外の溶媒を用いた場合は、付加物
結晶が生成し、得られた結晶が純粋な結晶と付加物結晶
の混合物となるため、熱ろ過、および20℃以上での乾
燥が必要となるが、ジメチルカーボネートの場合は、−
20℃から150℃の温度範囲での操作が可能であるた
め、設備面でも非常にシンプルになる。
As a means of crystallization, a method of crystallizing by evaporative concentration is preferable since the temperature dependence of the solubility is reduced in this temperature range. After the crystallization of the crystals, solid-liquid separation is performed by filtration.When the solution attached to the crystal surface returns to room temperature, when a solvent other than dimethyl carbonate is used, adduct crystals are formed, and the obtained crystals are pure. Since it becomes a mixture of crystals and adduct crystals, hot filtration and drying at 20 ° C. or higher are required. In the case of dimethyl carbonate, −
The operation in the temperature range of 20 ° C. to 150 ° C. is possible, so that the equipment is very simple.

【0018】以上の方法によりヘキサフルオロリン酸リ
チウムを晶出すれば、50μm以上の粒径を持つ結晶が
容易に得られる。さらに晶析条件をコントロールすれ
ば、1mm以上の結晶も得られる。このようにして得ら
れたヘキサフルオロリン酸リチウムの結晶は、単結晶ま
たは一次凝集晶であり、非常に純度が高く、保存時の安
定性においても優れている。
By crystallizing lithium hexafluorophosphate by the above method, a crystal having a particle size of 50 μm or more can be easily obtained. If the crystallization conditions are further controlled, crystals of 1 mm or more can be obtained. The crystal of lithium hexafluorophosphate thus obtained is a single crystal or a primary aggregated crystal, has a very high purity, and is excellent in storage stability.

【0019】[0019]

【実施例】以下実施例により本発明を具体的に説明する
が、本発明はかかる実施例により限定されるものではな
い。
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

【0020】実施例1 テフロン製反応器中で90gジメチルカーボネートに
5.2gフッ化リチウムを添加して、混合分散した。こ
の分散液を冷却して20℃を維持しながら、ガス導入管
を通して、五フッ化リンガスをバブリングした。ジメチ
ルカーボネート中に分散されたフッ化リチウムが消失し
た時点で反応を終了した。このときの五フッ化リンの消
費量は26gであった。
Example 1 In a Teflon-made reactor, 5.2 g of lithium fluoride was added to 90 g of dimethyl carbonate and mixed and dispersed. While the dispersion was cooled and maintained at 20 ° C., phosphorus pentafluoride gas was bubbled through a gas inlet tube. The reaction was terminated when lithium fluoride dispersed in dimethyl carbonate disappeared. At this time, the consumption of phosphorus pentafluoride was 26 g.

【0021】得られた溶液を特に温度制御せずに、撹拌
しながら1torr減圧で蒸発晶析を行った。気化熱を
奪われることにより、溶液の温度は5℃になった。ジメ
チルカーボネートが65g蒸発した時点で、晶出した結
晶を濾別し、室温で真空乾燥した。以上のようにしてヘ
キサフルオロリン酸リチウム15gを得た。得られたヘ
キサフルオロリン酸リチウムの平均粒径は300μm
で、元素分析により組成を確認したところ、付加物を含
まない純粋なヘキサフルオロリン酸リチウムであった。
また、不純物のフッ化水素濃度は50ppm以下(定量
下限)であった。
The obtained solution was subjected to evaporative crystallization under reduced pressure of 1 torr while stirring without particular temperature control. The temperature of the solution was reduced to 5 ° C. by removing the heat of vaporization. When 65 g of dimethyl carbonate had evaporated, the crystallized crystals were filtered off and dried in vacuo at room temperature. As described above, 15 g of lithium hexafluorophosphate was obtained. The average particle size of the obtained lithium hexafluorophosphate is 300 μm.
When the composition was confirmed by elemental analysis, pure lithium hexafluorophosphate containing no adduct was found.
In addition, the hydrogen fluoride concentration of the impurity was 50 ppm or less (the lower limit of quantification).

【0022】実施例2 フッ化水素を3000ppm含有するヘキサフルオロリ
ン酸リチウム45gをジメチルカーボネート75gに溶
解した。この溶液に種晶として、フッ化水素を100p
pm含有するヘキサフルオロリン酸リチウムを4g添加
したのち、液温を−5℃に保持して撹拌しながら1to
rr減圧で蒸発晶析を行った。ジメチルカーボネートが
40g蒸発した時点で、晶出した結晶を濾別し、室温で
真空乾燥した。以上のようにしてヘキサフルオロリン酸
リチウム29gを得た。得られたヘキサフルオロリン酸
リチウムの平均粒径は320μmで、元素分析により組
成を確認したところ、付加物を含まない純粋なヘキサフ
ルオロリン酸リチウムであった。また、不純物のフッ化
水素濃度は50ppm以下(定量下限)であった。
Example 2 45 g of lithium hexafluorophosphate containing 3000 ppm of hydrogen fluoride was dissolved in 75 g of dimethyl carbonate. 100p of hydrogen fluoride as a seed crystal in this solution
After adding 4 g of lithium hexafluorophosphate containing pm, the solution temperature was kept at -5 ° C. and stirred for 1 to
Evaporation crystallization was performed under rr reduced pressure. When 40 g of dimethyl carbonate had evaporated, the crystallized crystals were filtered off and dried in vacuo at room temperature. As described above, 29 g of lithium hexafluorophosphate was obtained. The average particle size of the obtained lithium hexafluorophosphate was 320 μm. The composition was confirmed by elemental analysis. As a result, it was pure lithium hexafluorophosphate containing no adduct. In addition, the hydrogen fluoride concentration of the impurity was 50 ppm or less (the lower limit of quantification).

【0023】比較例1 テフロン製反応器中で90gジエチルカーボネートに
5.2gフッ化リチウムを添加して、混合分散した。こ
の分散液を冷却して20℃を維持しながら、ガス導入管
を通して、五フッ化リンガスをバブリングした。ジエチ
ルカーボネート中に分散されたフッ化リチウムが消失し
た時点で反応を終了した。このときの五フッ化リンの消
費量は26gであった。
Comparative Example 1 In a Teflon-made reactor, 5.2 g of lithium fluoride was added to 90 g of diethyl carbonate and mixed and dispersed. While the dispersion was cooled and maintained at 20 ° C., phosphorus pentafluoride gas was bubbled through a gas inlet tube. The reaction was terminated when lithium fluoride dispersed in diethyl carbonate disappeared. At this time, the consumption of phosphorus pentafluoride was 26 g.

【0024】得られた溶液を特に温度制御せずに、撹拌
しながら1torr減圧で蒸発晶析を行った。気化熱を
奪われることにより、溶液の温度は10℃になった。ジ
エチルカーボネートが38g蒸発した時点で、全体が凝
固したため、この結晶を室温で真空乾燥した。
The obtained solution was subjected to evaporative crystallization under a reduced pressure of 1 torr while stirring without particular temperature control. The temperature of the solution became 10 ° C. by removing the heat of vaporization. When 38 g of diethyl carbonate was evaporated, the whole solidified, and thus the crystals were vacuum-dried at room temperature.

【0025】以上のようにして得られた結晶の平均粒径
は600μmで、元素分析により組成を確認したとこ
ろ、ヘキサフルオロリン酸リチウム1分子に対して、ジ
エチルカーボネートが2分子配位した付加物結晶であっ
た。
The crystals obtained as described above had an average particle size of 600 μm. The composition was confirmed by elemental analysis. The adduct was obtained by coordinating two molecules of diethyl carbonate to one molecule of lithium hexafluorophosphate. It was a crystal.

【0026】[0026]

【発明の効果】本発明によれば、従来の製造方法に比
べ、非常に純度が高く、保存時の安定性においても優れ
たヘキサフルオロリン酸リチウムを提供することができ
る。
According to the present invention, it is possible to provide lithium hexafluorophosphate having extremely high purity and excellent storage stability as compared with the conventional production method.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 川島 忠幸 山口県宇部市大字沖宇部5253番地 セント ラル硝子株式会社化学研究所内 (72)発明者 佐々木 広美 山口県宇部市大字沖宇部5253番地 セント ラル硝子株式会社化学研究所内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadayuki Kawashima 5253 Oki Obe, Oji, Ube City, Yamaguchi Prefecture Inside the Chemical Research Laboratory of Central Glass Co., Ltd. (72) Hiromi Sasaki 5253 Oki Ube Oaza, Ube City, Yamaguchi Prefecture, Central Glass Inside the Chemical Laboratory Co., Ltd.

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 ヘキサフルオロリン酸リチウムを、ヘキ
サフルオロリン酸リチウムとジメチルカーボネートから
なる溶液中より、−20℃から150℃の温度範囲でジ
メチルカーボネートを蒸発、濃縮により晶出させること
を特徴とするヘキサフルオロリン酸リチウムの製造方
法。
1. A method comprising: crystallizing lithium hexafluorophosphate from a solution comprising lithium hexafluorophosphate and dimethyl carbonate by evaporating and concentrating dimethyl carbonate in a temperature range of -20 ° C. to 150 ° C. For producing lithium hexafluorophosphate.
【請求項2】 晶出させたヘキサフルオロリン酸リチウ
ムの粒径が、50μm以上の結晶であることを特徴とす
る請求項1記載のヘキサフルオロリン酸リチウムの製造
方法。
2. The method for producing lithium hexafluorophosphate according to claim 1, wherein the crystallized lithium hexafluorophosphate has a crystal size of 50 μm or more.
【請求項3】 ジメチルカーボネート溶液中のヘキサフ
ルオロリン酸リチウムが、ジメチルカーボネート中でフ
ッ化リチウムと五フッ化リンとを反応させたものである
ことを特徴とする請求項1記載のヘキサフルオロリン酸
リチウムの製造方法。
3. The hexafluorophosphate according to claim 1, wherein the lithium hexafluorophosphate in the dimethyl carbonate solution is obtained by reacting lithium fluoride and phosphorus pentafluoride in dimethyl carbonate. Method for producing lithium oxide.
【請求項4】 ヘキサフルオロリン酸リチウムをジメチ
ルカーボネート中に溶解し、−20℃から150℃の温
度範囲で蒸発濃縮により再結晶させことを特徴とするヘ
キサフルオロリン酸リチウムの製造方法。
4. A process for producing lithium hexafluorophosphate, comprising dissolving lithium hexafluorophosphate in dimethyl carbonate and recrystallizing the solution by evaporating and concentrating it in a temperature range of -20 ° C. to 150 ° C.
【請求項5】 再結晶で得られた結晶が、粒径50μm
以上の結晶であることを特徴とする請求項4記載のヘキ
サフルオロリン酸リチウムの製造方法。
5. The crystal obtained by recrystallization has a particle size of 50 μm.
The method for producing lithium hexafluorophosphate according to claim 4, wherein the crystal is the above crystal.
【請求項6】 請求項1〜5のいずれかに記載の製造方
法で得られたヘキサフルオロリン酸リチウム結晶を、−
20℃から150℃の温度範囲で乾燥することを特徴と
するヘキサフルオロリン酸リチウムの製造方法。
6. The lithium hexafluorophosphate crystal obtained by the production method according to any one of claims 1 to 5,
A method for producing lithium hexafluorophosphate, comprising drying at a temperature in the range of 20 ° C to 150 ° C.
JP07982797A 1997-03-18 1997-03-31 Method for producing lithium hexafluorophosphate Expired - Fee Related JP3483099B2 (en)

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JP6495997 1997-03-18
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