JPS6211074B2 - - Google Patents
Info
- Publication number
- JPS6211074B2 JPS6211074B2 JP54135960A JP13596079A JPS6211074B2 JP S6211074 B2 JPS6211074 B2 JP S6211074B2 JP 54135960 A JP54135960 A JP 54135960A JP 13596079 A JP13596079 A JP 13596079A JP S6211074 B2 JPS6211074 B2 JP S6211074B2
- Authority
- JP
- Japan
- Prior art keywords
- membrane
- aqueous
- electrolysis
- fluorine
- anode
- 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
- 239000012528 membrane Substances 0.000 claims description 72
- 238000011282 treatment Methods 0.000 claims description 31
- 206010042674 Swelling Diseases 0.000 claims description 28
- 230000008961 swelling Effects 0.000 claims description 28
- 238000005868 electrolysis reaction Methods 0.000 claims description 26
- 238000005341 cation exchange Methods 0.000 claims description 20
- 229910052731 fluorine Inorganic materials 0.000 claims description 18
- 239000011737 fluorine Substances 0.000 claims description 18
- 239000000243 solution Substances 0.000 claims description 17
- 229920001577 copolymer Polymers 0.000 claims description 16
- 230000007062 hydrolysis Effects 0.000 claims description 15
- 238000006460 hydrolysis reaction Methods 0.000 claims description 15
- 239000007864 aqueous solution Substances 0.000 claims description 14
- 239000003513 alkali Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 12
- 238000005342 ion exchange Methods 0.000 claims description 12
- 239000002243 precursor Substances 0.000 claims description 9
- 150000001340 alkali metals Chemical group 0.000 claims description 7
- 229910052783 alkali metal Chemical group 0.000 claims description 6
- 239000012736 aqueous medium Substances 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 239000001257 hydrogen Substances 0.000 claims description 5
- 230000003301 hydrolyzing effect Effects 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical group [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 3
- 150000001336 alkenes Chemical class 0.000 claims description 3
- 239000000460 chlorine Substances 0.000 claims description 3
- 229910052801 chlorine Inorganic materials 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims description 3
- 125000005010 perfluoroalkyl group Chemical group 0.000 claims description 3
- 239000003495 polar organic solvent Substances 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 150000002431 hydrogen Chemical class 0.000 claims description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 1
- 150000002500 ions Chemical class 0.000 claims 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 39
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 17
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 17
- 238000000034 method Methods 0.000 description 12
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 9
- 239000011780 sodium chloride Substances 0.000 description 9
- 239000002609 medium Substances 0.000 description 8
- 239000003014 ion exchange membrane Substances 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 239000001103 potassium chloride Substances 0.000 description 4
- 235000011164 potassium chloride Nutrition 0.000 description 4
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 230000037303 wrinkles Effects 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 150000004702 methyl esters Chemical class 0.000 description 3
- -1 polyethylene Polymers 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical group C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229910001413 alkali metal ion Inorganic materials 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000012466 permeate Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 125000000542 sulfonic acid group Chemical group 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 125000002023 trifluoromethyl group Chemical group FC(F)(F)* 0.000 description 2
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- 235000010893 Bischofia javanica Nutrition 0.000 description 1
- 240000005220 Bischofia javanica Species 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 1
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 150000003842 bromide salts Chemical class 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229910001925 ruthenium oxide Inorganic materials 0.000 description 1
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 description 1
- GRONZTPUWOOUFQ-UHFFFAOYSA-M sodium;methanol;hydroxide Chemical compound [OH-].[Na+].OC GRONZTPUWOOUFQ-UHFFFAOYSA-M 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 238000012719 thermal polymerization Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000001291 vacuum drying Methods 0.000 description 1
- 239000002759 woven fabric Substances 0.000 description 1
Landscapes
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Description
本発明は、塩化アルカリ水溶液の電解方法、更
に詳しくは優れた電解特性とともに機械的特性を
有する含フツ素陽イオン交換膜を使用する塩化ア
ルカリ水溶液の電解方法に関するものである。
電解槽の陰極及び陽極との間を隔膜で区画し、
通常、陽極室に例えば塩化ナトリウム水溶液を供
給して電解することにより陰極室に水酸化ナトリ
ウムを製造する所謂二室法による隔膜電解方法は
公知である。近年ここにおける隔膜として、アル
カリ金属イオンのみを選択的に透過する陽イオン
交換膜を使用することが提案されている。なかで
も耐アルカリ性、耐塩素性を有する含弗素樹脂陽
イオン交換膜は優れたものとして提案されてい
る。かかる陽イオン交換膜を隔膜とする場合、実
質上電解液が透過せず、アルカリ金属イオンだけ
が選択的に透過するために、得られる水酸化アル
カリ中への塩化アルカリの混入が防止でき、純度
の点では相当満足したものが得られる。
なかでもイオン交換基として、式−COOM
（Ｍは水素又はアルカリ金属を表わす）を有する
カルボン酸系の含フツ素陽イオン交換膜を使用し
た場合には、スルホン酸系のイオン交換膜に比べ
て、製造する水酸アルカリの濃度が大きい場合で
も、電解における電流効率を高くできるという優
れた電解方法を提供することが知られている。
本発明は、かかる含フツ素陽イオン交換膜の塩
化アルカリの電解における電解電圧を、交換基が
スルホン酸基である場合も含めて、低減させる方
法について研究したところ、該目的を達成できる
新規な方法を見い出した。即ち、含フツ素陽イオ
ン交換膜を塩化アルカリの電解に使用するに先立
ち、これを特定の方式に従つて前処理することに
より、膜の電気抵抗を顕著に低下させるというこ
とを見い出した。
即ち、本発明は含フツ素陽イオン交換膜が一般
式、CF2＝CX−（OCF2CFY）l−（Ｏ）n−（CFY）o
Ａ（ここで、ｌは０〜３、ｍは０又は１、ｎは１
〜12であり、Ｘは−Ｆ又は−CF3であり、Ｙ，
Y′は−Ｆ又は炭素数１〜10のパーフルオロアル
キル基である。Ａは加水分解により−COOM又
は−SO3Mに転換しうる官能基を表わし、Ｍは水
素又はアルカリ金属原子を示す）を有するフルオ
ロビニル化合物と、一般式、CF2＝CZZ′（ここで
Ｚ，Z′は水素、塩素、フツ素又は−CF3である）
を有するフツ素化オルフインとの少なくとも二元
共重合体からなり、その片面の層のイオン交換基
前駆体を加水分解した後、水又はアルカリ金属の
中性塩水溶液又は極性有機溶媒水溶液からなる水
性媒体中で膨潤処理し、次いで残余のイオン交換
基前駆体を加水分解してなる陽イオン交換膜を使
用し、上記膨潤処理した面を陽極側に向けて陽極
室と陰極室とを区画した電解槽にて塩化アルカリ
水溶液を電解することを特徴とする電解方法にあ
る。
本発明における上記含フツ素陽イオン交換膜を
使用した電解方法により何故に上記に優れた特性
が得られるかについては、必ずしも明確ではない
が、以下のように推論される。即ち、本発明者の
知見によると、含フツ素陽イオン交換膜につい
て、予め膨潤処理したものはその処理層の厚みに
応じて膜の電気低抗を著しく低下させることがで
きる。しかし、膨潤処理した膜は塩化アルカリ電
解における電流効率については著しく低い。一方
塩化アルカリの電解における電流効率は、主に膜
の陰極側層で支配されるので電流効率の達成に必
要な陰極側の薄層を残して、膜の陽極側層を予め
膨潤処理した膜は、電気抵抗も低く、また電流効
率をも優れた性能を示すことになる。
また、本発明に従つて膨潤前処理したイオン交
換膜は、電解使用下において発生する皺もかなり
の程度抑制しうることも見い出された。
以下に、本発明について詳述すると本発明方法
において使用される含フツ素陽イオン交換膜は一
般式、CF2＝CX−（OCF2CFY）l−（Ｏ）n−
（CFY′）o−Ａ（ここでＸ，Ｙ，Y′l，ｍ，ｎ及び
Ａは上記と同じ）を有するフルオロビニル化合物
と一般式、CF2＝CZZ′（ここでＺ，Z′は上記と同
じ）を有するフツ素化オレフインとの少なくとも
二元共重合体からなる。なお、上記のように、Ａ
は加水分解により−COOM又は−SO3Mに転換で
きる官能基を表わすが、該基としては好ましく
は、−COOR、−COF−SO3R1、−SO2Fなどの極性
の小さい基が適切である。R1は炭奏数１〜10の
アルキル基である。
上記のうちでも、本発明では電解性能の点から
しても、また本発明によつてもたらされる効果の
点からしてもカルボン酸系イオン交換基の膜に対
してより有効である。しかしながら、膜は必ずし
も一種類の重合体で形成される必要はなく、例え
ば異なる交換基を有する二種類の共重合体を積層
してもよく、また一種類の共重合体から出発して
も、例えばその陰極側又は陽極側の交換基を変換
して、陽極側がスルホン酸系そして陰極側がカル
ボン酸系の交換基を有する共重合体から形成する
ことができる。
イオン交換膜の有する交換容量は、その電解性
能とも関係するので重要であり、本発明では好ま
しくは0.5〜4.0ミリ当量／グラム乾燥樹脂であ
る。交換容量は上記範囲よりも小さい場合も、大
きい場合も電解性能が低下するので不適当であ
り、特には0.9〜2.0ミリ当量／グラム乾燥樹脂が
好ましい。
イオン交換膜を形成する共重合体の分子量はメ
チルエステルタイプのポリマーの場合所定の容量
流速を示す温度で表現した場合、容量流速100mm
３／秒を示す温度〔ＴQ℃〕が好ましくは130〜
350℃、特に好ましくは300℃である。また、かか
る共重合体の製造に当つては、上記の各単量体の
一種以上を使用し、更には第３の単量体をも共重
合することにより、得られる膜を改質することが
できる。かくして、例えば、CF2＝CFORf（Rf
は炭素数１〜10のパーフルオロアルキル基）を併
用することにより、得られる膜に可撓性を付与し
たり、或は
CF2＝CF−CF＝CF2′ CF2＝CFO（CF2）1〜3CF
＝CF2等のジビニルモノマーを併用することによ
り、得られる共重合体を一部架橋せしめ、膜に機
械的強度を付与することができる。
フツ素化オレフインと、フルオロビニル化合
物、更には第三の単量体との共重合は、既知の任
意の手段で行なうことができる。即ち、必要に応
じて例えばハロゲン化炭化水素などの溶媒を使用
し、触媒重合、熱重合、放射線重合などにより重
合できる。また、かくして得られた共重合体から
イオン交換膨脂膜に製膜する手段も、既知の例え
ば、プレス成型、ロール成型、押出し成型、溶液
流延法、デイスパージヨン成型又は粉末成型など
により行なわれる。かくして、膜厚が好ましくは
20〜600ミクロン、更には50〜400ミクロンにせし
めるのが好ましい。
かかる含フツ素重合体の製膜工程に続いて、本
発明では以下のようにして電解に使用されるに際
して前処理が行なわれる。
かかる前処理は、まず膜の片面層のイオン交換
基前駆体を加水分解することにより行なわれる前
処理は、イオン交換膜の片面に行なうことが必要
であり、好ましくは10〜100μ厚、特には20〜50
μ厚の層を残して片面層の交換基前駆体かつ加水
分解される。加水分解に続いて、膨潤処理が行な
われるが、処理すべき厚さの制御及び使用媒体の
取り扱いの容易さから両処理は異なる媒体中で行
なうことが適切である。
加水分解処理は、膜の有する交換基を−
COOM又は−CO3Mに転換させる加水分解能力を
有する媒体が選択される。かかる媒体としては、
好ましくはアルカリ金属又はアルカリ土類金属の
水酸化物水溶液、特には電解する塩化アルカリと
同じ種類のアルカリ金属の水酸化物水溶液が使用
される。加水分解は処理層の厚みを制御するため
比較的高濃度、高温で短時間で行なうことが好ま
しく、例えば20〜40重量％の媒体で20〜90℃で１
〜24時間で実施される。膨潤処理は、水又はアル
カリ金属の中性塩水溶液又は極性有機溶媒水溶液
からなる水性媒体中で行なわれる。アルカリ金属
の中性塩としては、ナトリウム又はカリウムなど
の塩化物、臭化物、硫酸塩又はリン酸塩などが例
示される。極性有機溶媒としては、メタノール、
エタノール、プロパノール、エチレングリコー
ル、セロソルブなどの水酸基含有有機媒体が例示
される。
膨潤処理の条件は、使用する水性媒体の種類に
応じて適切な媒体濃度、温度及び処理時間が選ば
れる。膜に対する膨潤能力が大きい媒体の場合に
はそれだけ温和な条件、即ち小さい濃度、低い温
度、短い処理時間が選ばれる。また、上記の逆の
場合は、厳しい条件が選ばれる。例えば無機水性
媒体中では80℃以上の処理温度が一方、有機水性
媒体中では室温程度もよい。処理時間も１分〜
100時間が選ばれる。
上記のように膨潤処理は使用する媒体の種類に
よつても異なるが、本発明者の研究によると膨潤
処理そして続く残りの層のイオン交換基前駆体の
加水分解処理後の膜の重量増加率（△ＷR）が所
定の範囲になるように行なうことが好ましい。該
範囲は、本発明者の研究によると、イオン交換容
量（ＡR）の関数として表示される。即ち、横軸
にＡRをとると、それは、上辺が△ＷR＝
3.9e1.7AR、下辺が△ＷR＝0.8e1.7ARになるように
せしめられる。得られる膜の機械的特性及び電解
性能の点からして、△ＷRは、上記のうちでも特
に食塩水溶液の電解用の場合には、△ＷR＝
1.0e1.7AR、上辺：△ＷR＝2.3e1.7AR範囲に制御す
るのが好ましい。
膨潤処理に続いて膜の残りのイオン交換基前駆
体の加水分解と同様な媒体、濃度、時間が採用さ
れ実施される。
上記した加水分解及び膨潤処理は通常、常圧で
行なわれるが、必要に応じて減圧下又は１〜20
Kg／cm2の加圧下で行なうことができる。これらの
処理する手段としては予め二放の膜を相互に圧着
し、圧着層界面に液が侵入しないようにして、こ
れを処理媒体中に浸漬して、加水分解、膨潤処理
する。而る後二枚の膜を剥がして膜全体を加水分
解媒体中に浸漬するなど任意の方式が採用でき
た。
更に、含フツ素陽イオン交換膜は必要に応じ
て、製膜時にポリエチレン、ポリプロピレンなど
のオレフインの重合体、好ましくはポリテトラフ
ルオロエチレン、エチレンとテトラフルオロエチ
レンとの共重合体などの含フツ素重合体をブレン
ドして成型することもでき、又はこれらの重合体
からなる布、ネツトなどの織物、不織布或いは多
孔性のフイルムからなる支持体により共重合体を
支持せしめて膜を補強することができる。なお記
載するまでもないが、かかるブレンド又は支持体
を使用した場合には、これらブレンド又は支持体
を構成する樹脂の重さは前記したイオン交換容量
には算入されない。
なお、本発明では使用に先立ちイオン交換膜を
最終的に全体を膨潤処理することにより、電解時
に発生する皺の発生を更に完全に抑制することが
できる。かかる膨潤処理は前記した膨潤処理と同
様な媒体が使用されるが、膜の電気的性質を損な
わないよう温和な条件で行なわれる。
本発明の含フツ素陽イオン交換膜を使用して、
塩化アルカリの電解を行ない、水酸化アルカリを
製造する手段としては、既知のいずれの隔膜電解
の方式をも採用することができるが、そこで重要
なことは膜の膨潤処理面を陽極側に向けて設置使
用することでこれを逆にした場合には比較例に示
される如く、本発明の所記の効果は全く達成され
ない。なお電解時の電解電圧及び電流密度は、そ
れぞれ好ましくは2.3〜5.5ボルト、５〜100A／ｄ
m2が採用できる。電解に使用される陽極は例えば
黒鉛又は、チタン母体に白金族金属を被覆した
り、白金族金属の酸化物を被覆した寸法安定性を
有する耐食性電極を適宜使用することができる。
また、電解槽の形式も単極槽、複極槽などのいず
れの方式も採用できる。
かくして、例えば本発明の陽イオン交換膜に
て、陽極と陰極とを区画して陽極室と陰極室とを
構成し、陽極室に塩化アルカリ水溶液を供給して
電解し、陰極室から水酸化アルカリを得る所謂二
室型槽の場合でも、２規定以上の濃度の塩化ナト
リウム水溶液を原料にして、40〜120℃、好まし
くは70〜100℃、５〜50A／ｄm2の電流密度で電
解することにより、40％以上の高濃度の水酸化ナ
トリウムが、いずれも90％以上の高電流効率で製
造できる。
以下に、本発明を更に具体的に示すために実施
例を挙げるが、本発明は上記の記載及び下記の実
施例に限定されないことはもちろんである。
なお、以下の実施例における陽イオン交換膜の
交換容量は次のようにして求めた。即ち製膜され
たメチルエステル型膜１ｇを0.3NaOHメタノー
ル溶液、10ml中で60℃、16時間放置し、完全に加
水分解した。この溶液中のNaOHの残存量を0.1N
のHClで逆滴定することにより求めた。
容量流速は、高化式フローテスターを用いメチ
ルエステルタイプのポリマーについて圧力30Kg／
cm2で0.1mm径、長さ２mmのオリフイスを流出する
速度を測定して求めた。
また、重量増加率は、処理液より膜をとり出し
付着液をぬぐつて重量を測定し、更に水洗し、
130℃８時間、真空乾燥した時の重量を測定し、
この値を基準として重量増加率を求める。
実施例 １
テトラフルオロエチレンと
CF2＝CFO（CF2）3COOCH3とを共重合せしめ
て、交換容量1.46ミリ当量／ｇ乾燥樹脂ＴQが230
℃である含フツ素共重合体を製造した。共重合
は、アゾイソプチロニトリルを触媒として、17.5
気圧で行なつた。得られた共重合体は、230℃で
プレス成型して、膜厚を300ミクロンとして、膜
成形した。かかる二枚の膜を圧着し、これを25
％、90℃のNaOH水溶液中で５時間処理して加水
分解処理した。次いで水洗した後第１表に示され
る種々の濃度のそれぞれの媒体中でしかも種々の
条件にて浸漬処理を行なうことにより、膨潤処理
した二枚の膜をはがし膜の断面をクリスタルバイ
オレツト水溶液にて染色したところ、250μの部
分が強く染色された。次いでそれぞれの膜を上記
と同じ条件で残りの交換基を加水分解した。更に
膜を2Nの食塩水中で24時間膨潤処理した。かか
る膜を使用して以下の条件でNaCl水溶液の電解
を行ない膜の電解性能及び50日間電解後の膜にお
ける皺の発生状況を観察した。これらの結果を第
１表に示す。
電解槽は、上記の含フツ素陽イオン交換膜の膨
潤処理面を陽極側に向けて陽極と陰極とを区画
し、二室型槽とし、陽極には酸化ルテニウム被覆
チタン電極、陽極にはステンレスをそれぞれ使用
し、極間距離を0.5cm、膜の有効面積を25cm2とし
た。そして電解槽の陽極室には、5Nの塩化ナト
リウム水溶液、陰極室には、25％の水液化ナトリ
ウム水溶液を仕込み、陽極室には5Nの塩化ナト
リウム水溶液を180c.c.／時、陰極室には、そこか
ら得られる水酸化ナトリウムの濃度が、いずれも
約35％になるように所定量の水をそれぞれ約35％
になるように所定量の水をそれぞれ供給しながら
電解槽の電流密度20A／ｄm2、液温90℃にて電解
を行なつた。
陽極室から塩化ナトリウム水溶液を溢流せしめ
る一方、陰極室から溢流する水酸化ナトリウムか
らその電流効率を求めた。
なお、比較例として、イオン交換膜をそのまま
上記と同じ条件で加水分解だけをした膜を使用し
た場合、比較例２として上記と同様にして加水分
解し、片面を膨潤処理した膜を、膨潤処理面を陰
極側に向けて使用した場合、更に比較例３とし
て、両面を加水分解し、膨潤処理した膜を使用し
た場合のそれぞれの電解結果を示す。
The present invention relates to a method for electrolyzing an aqueous alkali chloride solution, and more particularly to a method for electrolyzing an aqueous alkali chloride solution using a fluorine-containing cation exchange membrane having excellent electrolytic properties and mechanical properties. A diaphragm is used to separate the cathode and anode of the electrolytic cell,
Generally, a diaphragm electrolysis method using a so-called two-chamber method is known, in which sodium hydroxide is produced in a cathode chamber by supplying, for example, an aqueous sodium chloride solution to an anode chamber and electrolyzing it. In recent years, it has been proposed to use a cation exchange membrane that selectively transmits only alkali metal ions as the diaphragm. Among them, fluorine-containing resin cation exchange membranes having alkali resistance and chlorine resistance have been proposed as being excellent. When such a cation exchange membrane is used as a diaphragm, the electrolyte does not substantially permeate through it, and only alkali metal ions selectively permeate therethrough, which prevents alkali chloride from being mixed into the resulting alkali hydroxide and improves purity. I am quite satisfied with this point. Among them, as an ion exchange group, the formula −COOM
(M represents hydrogen or an alkali metal) When using a carboxylic acid-based fluorine-containing cation exchange membrane, the concentration of the alkali hydroxide produced is higher than that of a sulfonic acid-based ion exchange membrane. It is known to provide an excellent electrolysis method that can increase the current efficiency in electrolysis even in cases where the current efficiency is high. The present invention has researched a method for reducing the electrolytic voltage in alkali chloride electrolysis of such a fluorine-containing cation exchange membrane, including when the exchange group is a sulfonic acid group, and has found a novel method that can achieve the objective. I found a way. That is, it has been found that by pretreating a fluorine-containing cation exchange membrane according to a specific method before using it for electrolysis of alkali chloride, the electrical resistance of the membrane can be significantly lowered. That is, in the present invention, the fluorine-containing cation exchange membrane has the general formula: CF 2 =CX-(OCF 2 CFY) l -(O) n -(CFY) o
A (where l is 0 to 3, m is 0 or 1, n is 1
~12, X is -F or -CF3 , Y,
Y' is -F or a perfluoroalkyl group having 1 to 10 carbon atoms. A represents a functional group that can be converted into -COOM or -SO 3 M by hydrolysis, and M represents hydrogen or an alkali metal atom . , Z' is hydrogen, chlorine, fluorine or -CF3 )
After hydrolyzing the ion-exchange group precursor on one side of the copolymer with a fluorinated olfin having An electrolysis method using a cation exchange membrane prepared by swelling in a medium and then hydrolyzing the remaining ion exchange group precursor, and partitioning an anode chamber and a cathode chamber with the swelling surface facing the anode side. An electrolysis method characterized by electrolyzing an aqueous alkali chloride solution in a tank. Although it is not necessarily clear why the above-mentioned excellent properties are obtained by the electrolysis method using the fluorine-containing cation exchange membrane of the present invention, it is inferred as follows. That is, according to the findings of the present inventors, when a fluorine-containing cation exchange membrane is subjected to a swelling treatment in advance, the electrical resistance of the membrane can be significantly lowered depending on the thickness of the treated layer. However, the swelling-treated membrane has a significantly lower current efficiency in alkali chloride electrolysis. On the other hand, the current efficiency in alkali chloride electrolysis is mainly controlled by the cathode side layer of the membrane, so a membrane in which the anode side layer of the membrane is pre-swelled, leaving a thin layer on the cathode side necessary to achieve current efficiency, is , low electrical resistance and excellent current efficiency. It has also been found that ion exchange membranes pre-swelled according to the present invention can also significantly suppress wrinkles that occur during electrolytic use. The present invention will be described in detail below. The fluorine-containing cation exchange membrane used in the method of the present invention has the general formula, CF 2 =CX-(OCF 2 CFY) l - (O) n -
(CFY′) o −A (where X, Y, Y′l, m, n and A are the same as above) and the general formula CF 2 =CZZ′ (where Z, Z′ are (same as above) with a fluorinated olefin. Furthermore, as mentioned above, A
represents a functional group that can be converted into -COOM or -SO 3 M by hydrolysis, and preferably a less polar group such as -COOR, -COF-SO 3 R 1 or -SO 2 F is suitable. It is. R 1 is an alkyl group having a carbon number of 1 to 10. Among the above, the present invention is more effective for membranes with carboxylic acid-based ion exchange groups both in terms of electrolytic performance and in terms of the effects brought about by the present invention. However, the membrane does not necessarily have to be formed of one type of polymer; for example, two types of copolymers having different exchange groups may be laminated, or even if starting from one type of copolymer, For example, the exchange group on the cathode side or the anode side can be changed to form a copolymer having a sulfonic acid exchange group on the anode side and a carboxylic acid exchange group on the cathode side. The exchange capacity of the ion exchange membrane is important since it is also related to its electrolytic performance, and in the present invention it is preferably 0.5 to 4.0 meq/g dry resin. If the exchange capacity is smaller or larger than the above range, it is inappropriate because the electrolytic performance will deteriorate, and 0.9 to 2.0 milliequivalents/g dry resin is particularly preferred. In the case of a methyl ester type polymer, the molecular weight of the copolymer that forms the ion exchange membrane is expressed at a temperature that indicates a specified volume flow rate, and the volume flow rate is 100 mm.
3 /sec [T Q °C] is preferably 130~
The temperature is 350°C, particularly preferably 300°C. In addition, when producing such a copolymer, the resulting membrane may be modified by using one or more of the above monomers and also copolymerizing a third monomer. I can do it. Thus, for example, CF 2 =CFORf(Rf
is a perfluoroalkyl group having 1 to 10 carbon atoms) to impart flexibility to the resulting film, or CF 2 = CF−CF=CF 2 ′ CF 2 = CFO (CF 2 ) 1~ 3CF
By using a divinyl monomer such as CF 2 in combination, the resulting copolymer can be partially crosslinked and mechanical strength can be imparted to the membrane. Copolymerization of the fluorinated olefin, the fluorovinyl compound, and further the third monomer can be carried out by any known method. That is, polymerization can be carried out by catalytic polymerization, thermal polymerization, radiation polymerization, etc., using a solvent such as a halogenated hydrocarbon, if necessary. Further, the means for forming an ion-exchange swollen membrane from the thus obtained copolymer may be performed by known methods such as press molding, roll molding, extrusion molding, solution casting, dispersion molding, or powder molding. It can be done. Thus, the film thickness is preferably
The thickness is preferably 20 to 600 microns, more preferably 50 to 400 microns. Following the step of forming a film of the fluorine-containing polymer, in the present invention, pretreatment is performed as follows before use in electrolysis. Such pretreatment is carried out by first hydrolyzing the ion exchange group precursor on one side of the membrane.The pretreatment must be carried out on one side of the ion exchange membrane, preferably with a thickness of 10 to 100μ, particularly 20-50
The exchange group precursor is hydrolyzed on one side, leaving a μ-thick layer. Hydrolysis is followed by a swelling treatment, but both treatments are suitably carried out in different media for the purpose of controlling the thickness to be treated and ease of handling of the media used. The hydrolysis treatment removes the exchange groups of the membrane from -
A medium is selected that has the ability to hydrolyze the conversion to COOM or -CO3M . Such media include:
Preferably, an aqueous alkali metal or alkaline earth metal hydroxide solution is used, in particular an aqueous alkali metal hydroxide solution of the same type as the alkali chloride to be electrolyzed. In order to control the thickness of the treated layer, hydrolysis is preferably carried out at a relatively high concentration and high temperature for a short period of time.
Will be implemented in ~24 hours. The swelling treatment is carried out in an aqueous medium consisting of water or an aqueous solution of a neutral salt of an alkali metal or an aqueous solution of a polar organic solvent. Examples of neutral salts of alkali metals include chlorides, bromides, sulfates, and phosphates of sodium or potassium. Examples of polar organic solvents include methanol,
Examples include hydroxyl group-containing organic media such as ethanol, propanol, ethylene glycol, and cellosolve. As conditions for the swelling treatment, appropriate medium concentration, temperature, and treatment time are selected depending on the type of aqueous medium used. In the case of a medium that has a large swelling capacity for the membrane, milder conditions are chosen, ie, lower concentrations, lower temperatures, and shorter treatment times. In the opposite case, stricter conditions are selected. For example, in an inorganic aqueous medium, a treatment temperature of 80° C. or higher is preferable, while in an organic aqueous medium, a treatment temperature of about room temperature is preferable. Processing time is 1 minute ~
100 hours will be selected. As mentioned above, the swelling treatment differs depending on the type of medium used, but according to the research of the present inventors, the weight increase rate of the membrane after the swelling treatment and the subsequent hydrolysis treatment of the ion exchange group precursor of the remaining layer. It is preferable to perform this so that (ΔW R ) falls within a predetermined range. The range is expressed as a function of ion exchange capacity (A R ) according to the inventor's research. That is, if we take A R on the horizontal axis, it means that the upper side is △W R =
3.9e 1.7 A R and the lower side is made to be △W R =0.8e 1.7 A R. From the point of view of the mechanical properties and electrolytic performance of the obtained membrane, △W R is △W R =
1.0e 1.7 A R , upper side: △W R =2.3e 1.7 A R is preferably controlled within the range. The swelling process is followed by hydrolysis of the remaining ion-exchange group precursors of the membrane using similar media, concentrations, and times. The above-mentioned hydrolysis and swelling treatments are usually carried out at normal pressure, but if necessary, they may be carried out under reduced pressure or
It can be carried out under pressure of Kg/cm 2 . As a means for these treatments, two membranes are pressed together in advance, so that no liquid enters the interface between the pressed layers, and then immersed in a treatment medium for hydrolysis and swelling treatment. After that, any method could be used, such as peeling off the two membranes and immersing the entire membrane in the hydrolysis medium. Furthermore, the fluorine-containing cation exchange membrane may be formed using a fluorine-containing cation exchange membrane such as an olefin polymer such as polyethylene or polypropylene, preferably a fluorine-containing cation exchange membrane such as polytetrafluoroethylene or a copolymer of ethylene and tetrafluoroethylene. The copolymer can be blended and molded, or the membrane can be reinforced by supporting the copolymer with a support made of cloth, net, or other woven fabric, nonwoven fabric, or porous film made of these polymers. can. It goes without saying that when such a blend or support is used, the weight of the resin constituting the blend or support is not included in the above-mentioned ion exchange capacity. In the present invention, by finally subjecting the entire ion exchange membrane to a swelling treatment prior to use, the generation of wrinkles that occur during electrolysis can be more completely suppressed. This swelling treatment uses the same medium as the swelling treatment described above, but is carried out under mild conditions so as not to impair the electrical properties of the membrane. Using the fluorine-containing cation exchange membrane of the present invention,
Any known diaphragm electrolysis method can be used to electrolyze alkali chloride to produce alkali hydroxide, but the important thing is that the swelling treated side of the membrane faces the anode side. When this is reversed by installation and use, the effects described in the present invention are not achieved at all, as shown in the comparative example. The electrolytic voltage and current density during electrolysis are preferably 2.3 to 5.5 volts and 5 to 100 A/d, respectively.
m2 can be adopted. As the anode used for electrolysis, a corrosion-resistant electrode having dimensional stability, such as graphite or a titanium base coated with a platinum group metal or an oxide of a platinum group metal, can be used as appropriate.
Furthermore, the electrolytic cell may be of any type, such as a monopolar cell or a bipolar cell. Thus, for example, in the cation exchange membrane of the present invention, an anode and a cathode are separated to form an anode chamber and a cathode chamber, an alkali chloride aqueous solution is supplied to the anode chamber for electrolysis, and alkali hydroxide is removed from the cathode chamber. Even in the case of a so-called two-chamber type tank in which the electrolyte is obtained, an aqueous sodium chloride solution with a concentration of 2N or higher is used as a raw material, and electrolysis is carried out at a temperature of 40 to 120°C, preferably 70 to 100°C, and a current density of 5 to 50 A/ dm2 . With this method, sodium hydroxide with a high concentration of 40% or more can be produced with a high current efficiency of 90% or more. Examples are given below to more specifically illustrate the present invention, but it goes without saying that the present invention is not limited to the above description and the following examples. In addition, the exchange capacity of the cation exchange membrane in the following examples was determined as follows. That is, 1 g of the formed methyl ester type membrane was left in 10 ml of 0.3 NaOH methanol solution at 60° C. for 16 hours to completely hydrolyze it. The remaining amount of NaOH in this solution is 0.1N.
It was determined by back titration with HCl. The volumetric flow rate was determined using a Koka type flow tester at a pressure of 30 kg/kg for methyl ester type polymer.
It was determined by measuring the flow rate through an orifice with a diameter of 0.1 mm and a length of 2 mm in cm 2 . In addition, the weight increase rate can be determined by taking out the membrane from the treatment solution, wiping off the adhering liquid, measuring the weight, and then washing it with water.
Measure the weight after vacuum drying at 130℃ for 8 hours,
The weight increase rate is calculated based on this value. Example 1 Tetrafluoroethylene and CF 2 = CFO (CF 2 ) 3 COOCH 3 were copolymerized to give an exchange capacity of 1.46 milliequivalents/g dry resin T Q of 230
A fluorine-containing copolymer was produced. The copolymerization was carried out using azoisobutyronitrile as a catalyst, at 17.5
It was done using atmospheric pressure. The obtained copolymer was press-molded at 230°C to form a film with a film thickness of 300 microns. Press these two membranes together and
%, and was treated for 5 hours in an aqueous NaOH solution at 90°C for hydrolysis. Next, after washing with water, the two swollen membranes were peeled off by immersion in the respective media of various concentrations shown in Table 1 under various conditions, and the cross section of the membrane was immersed in an aqueous crystal violet solution. When the sample was stained, the 250μ area was strongly stained. Each membrane was then subjected to the same conditions as above to hydrolyze the remaining exchange groups. Furthermore, the membrane was subjected to swelling treatment in 2N saline for 24 hours. Using this membrane, an aqueous NaCl solution was electrolyzed under the following conditions, and the electrolytic performance of the membrane and the occurrence of wrinkles in the membrane after 50 days of electrolysis were observed. These results are shown in Table 1. The electrolytic cell is a two-chambered cell, with the swelling treated surface of the fluorine-containing cation exchange membrane facing the anode side and an anode and a cathode separated.The anode is a ruthenium oxide coated titanium electrode, and the anode is a stainless steel were used, the distance between the electrodes was 0.5 cm, and the effective area of the membrane was 25 cm 2 . Then, the anode chamber of the electrolytic cell is charged with 5N sodium chloride aqueous solution, the cathode chamber is charged with 25% liquefied sodium aqueous solution, and the anode chamber is charged with 5N sodium chloride aqueous solution at 180 c.c./hour into the cathode chamber. The predetermined amount of water is added to approximately 35% of each so that the concentration of sodium hydroxide obtained from it is approximately 35%.
Electrolysis was carried out at a current density of 20 A/dm 2 in the electrolytic cell and a liquid temperature of 90° C. while supplying a predetermined amount of water so that the following values were obtained. While the sodium chloride aqueous solution overflowed from the anode chamber, the current efficiency was determined from the sodium hydroxide overflowing from the cathode chamber. In addition, as a comparative example, when using an ion exchange membrane that was only hydrolyzed under the same conditions as above, as a comparative example 2, a membrane that was hydrolyzed in the same manner as above and subjected to swelling treatment on one side was used. The electrolysis results are shown when the membrane is used with its surface facing the cathode side, and when a membrane subjected to hydrolysis and swelling treatment on both sides is used as Comparative Example 3.
【表】
実施例 ２
テトラフルオロエチレンとCF2＝CFO
（CF2）3COOCHC3とを重合して交換容量1.23ミリ
当量／ｇ乾燥樹脂、ＴQが230℃の共重合体を得
た。230℃でプレス成型して300μのフイルムを得
た。かかる２枚の膜を圧着し、これを25％、90℃
のNaOH水溶液中で20時間処理して加水分解し
た。次いで水洗した後、水中で１時間の煮沸を行
なつた。
２枚の膜をはがし膜の断面をクリスタルバイオ
レツトで染色したところ250μの部分が強く染色
されていた。上記と同じ条件で残りの交換基を加
水分解した。この時の△ＷRは10％であつた。か
かる膜を使用して実施例１と同様にしてNaCl水
溶液の電解を50日間行なつたところ電流効率は97
％であり槽電圧は3.50Vであつた。
実施例 ３
実施例２と同様にして作製した膜を用い塩化カ
リウム（KCl）水溶液をKCl分解率50％で90℃、
20A／ｄm2でKOH濃度35％にて50日間電解し
た。電解の結果、電流効率は97％であり、槽電圧
は3.40Vであつた。
実施例 ４
テトラフルオロエチレンと
CF2＝CFOCF2CF（CF3）Ｏ（CF2）3COOCH3
との共重合体（交換容量1.20ミリ当量／ｇ乾燥樹
脂、ＴQは200℃）を200℃でプレス成型して膜厚
300μのフイルムを得た。かかる２枚の膜を圧着
し、これを25％、90℃のKOH水溶液中で３時間
処理して加水分解処理をした。水洗した後、水90
℃、40hrの膨潤処理をした。２枚の膜をはがし、
膜断面をクリスタルバイオレツトにて染色したと
ころ200μの部分が強く染色されていた。上記と
同じ条件で残りの交換基を加水分解し更に、IN
のKCl水溶液中で24時間膨潤処理した。この時の
△ＷRは16％であつた。かかる膜を使用して実施
例３と同様にしてKCl水溶液の電解を50日間行な
つたところ電流効率は96％であり槽電圧は3.4V
であつた。電解後、膜には皺は認められなかつ
た。
実施例 ５
CF2＝CF2とCF2＝CFO（CF2）3COOCH3のコ
ポリマーの膜（容量＝1.42meq／gTQ＝225℃膜
厚300μ大きさ10cm×10cm）の２枚をPTFEスペ
ーサーを界して重ね端部をシールした。これを50
％NaOH中110℃、16時間の処理を行なつた。こ
の後、２枚の膜を分離し、上記処理面を内側にし
て重ね再び端部をシールした。
これを25％NaOH90℃中２時間浸漬し、更に水
洗した後、水中90℃16hrの膨潤処理を行なつた。
この時点で２枚の膜を分離し、水洗したのち、ク
リスタルバイオレツトで染色したところ膨潤処理
面から150μと50％NaOH処理面から60μが染色
されたが中心部40μ程度は染色されなかつた。こ
の膜を更に25％NaOH90℃で16hrの浸漬処理を行
なつた。この膜をＫ塩型にした後膜断面の螢光Ｘ
線分析を行なつたところ、50％NaOH処理面から
10μ程の交換容量が１，2meq／ｇに低下した。
この膜を用い実施例１と同様にしてNaCl水溶液
の電解を50日間行なつた。別に50％NaOH処理の
み行ない膨潤処理を行なわない膜について電解性
能を示した。
△ＷR（％） 電流効率（％） 電圧（Ｖ）
実施例５
17.0 97 3.40
比較例３
8.5 97 6.50[Table] Example 2 Tetrafluoroethylene and CF 2 =CFO
(CF 2 ) 3 COOCHC 3 was polymerized to obtain a copolymer with an exchange capacity of 1.23 meq/g dry resin and a T Q of 230°C. Press molding was performed at 230°C to obtain a 300μ film. Press these two membranes together and heat them at 25% at 90°C.
Hydrolysis was carried out by treatment in an aqueous NaOH solution for 20 hours. Then, after washing with water, it was boiled in water for 1 hour. When the two membranes were peeled off and a cross section of the membrane was stained with crystal violet, a 250μ area was strongly stained. The remaining exchange groups were hydrolyzed under the same conditions as above. At this time, △W R was 10%. When electrolysis of NaCl aqueous solution was carried out for 50 days using this membrane in the same manner as in Example 1, the current efficiency was 97.
% and the cell voltage was 3.50V. Example 3 Using a membrane prepared in the same manner as in Example 2, a potassium chloride (KCl) aqueous solution was heated at 90°C with a KCl decomposition rate of 50%.
Electrolysis was carried out for 50 days at 20 A/dm 2 and a KOH concentration of 35%. As a result of electrolysis, the current efficiency was 97% and the cell voltage was 3.40V. Example 4 Tetrafluoroethylene and CF 2 = CFOCF 2 CF(CF 3 )O(CF 2 ) 3 COOCH 3
(exchange capacity 1.20 meq/g dry resin, TQ is 200℃) was press-molded at 200℃ to determine the film thickness.
A 300μ film was obtained. The two membranes were pressed together and treated for 3 hours in a 25% KOH aqueous solution at 90°C for hydrolysis. After washing with water, water 90%
Swelling treatment was performed at ℃ for 40 hours. Peel off the two membranes,
When a cross section of the membrane was stained with crystal violet, a 200μ area was strongly stained. The remaining exchange groups were hydrolyzed under the same conditions as above and further IN
Swelling treatment was carried out in a KCl aqueous solution for 24 hours. At this time, △W R was 16%. When this membrane was used to electrolyze a KCl aqueous solution for 50 days in the same manner as in Example 3, the current efficiency was 96% and the cell voltage was 3.4V.
It was hot. After electrolysis, no wrinkles were observed in the membrane. Example 5 Two copolymer films of CF 2 = CF 2 and CF 2 = CFO (CF 2 ) 3 COOCH 3 (capacity = 1.42 meq/gT Q = 225°C, film thickness 300 μ, size 10 cm x 10 cm) were separated by a PTFE spacer. The overlapped ends were sealed by separating the edges. 50 of this
% NaOH at 110° C. for 16 hours. Thereafter, the two membranes were separated and stacked with the treated surfaces inside, and the ends were sealed again. This was immersed in 25% NaOH at 90°C for 2 hours, further washed with water, and then subjected to swelling treatment in water at 90°C for 16 hours.
At this point, the two membranes were separated, washed with water, and then stained with crystal violet. 150μ from the swelling treated side and 60μ from the 50% NaOH treated side were stained, but about 40μ in the center was not stained. This membrane was further immersed in 25% NaOH at 90°C for 16 hours. After converting this film into a K-salt type, the fluorescence of the cross section of the film
When line analysis was performed, it was found that from the 50% NaOH treated surface
The exchange capacity of about 10 μ decreased to 1.2 meq/g.
Using this membrane, electrolysis of an aqueous NaCl solution was carried out for 50 days in the same manner as in Example 1. Separately, the electrolytic performance of a membrane treated with 50% NaOH without any swelling treatment was shown. △W R (%) Current efficiency (%) Voltage (V) Example 5
17.0 97 3.40 Comparative example 3
8.5 97 6.50
Claims (1)
（CFY′）o−Ａ（ここで１は０〜３、ｍは０又は
１、ｎは１〜12であり、Ｘは−Ｆ又は−CF3であ
り、Ｙ，Y′は−Ｆ又は炭素数１〜10のパーフル
オロアルキル基である。Ａは加水分解により−
COOM又は−SO3Mに転換しうるイオン交換基前
駆体を表し、Ｍは水素又はアルカリ金属原子を示
す）を有するフルオロビニル化合物と、一般式、
CF2＝CZZ′（ここでＺ，Z′は、水素、塩素、フツ
素又は−CF3である）を有するフツ素化オレフイ
ンとの少なくとも二元共重合体からなり、その片
面の層のイオン交換基前駆体を加水分解した後、
水又はアルカリ金属の中性塩水溶液又は極性有機
溶媒水溶液からなる水性媒体中で膨潤処理し、次
いで残余のイオン交換基前駆体を加水分解してな
る陽イオン交換膜を使用し、上記膨潤処理した面
を陽極側に向けて陽極室と陰極室とを区画した電
解槽にて、塩化アルカリ水溶液を電解することを
特徴とする電解方法。1 General formula, CF 2 = CX− (OCF 2 CFY) 1 −(O) n −
(CFY') o -A (where 1 is 0 to 3, m is 0 or 1, n is 1 to 12, X is -F or -CF 3 , Y, Y' are -F or carbon It is a perfluoroalkyl group of number 1 to 10. A is - by hydrolysis.
represents an ion exchange group precursor convertible to COOM or -SO3M , M represents hydrogen or an alkali metal atom), and a fluorovinyl compound having the general formula,
consisting of at least a binary copolymer with a fluorinated olefin having CF 2 =CZZ' (where Z, Z' are hydrogen, chlorine, fluorine or -CF 3 ), the ion of the layer on one side After hydrolyzing the exchange group precursor,
The above swelling treatment was performed using a cation exchange membrane obtained by performing swelling treatment in an aqueous medium consisting of water or an aqueous solution of a neutral salt of an alkali metal or an aqueous solution of a polar organic solvent, and then hydrolyzing the remaining ion exchange group precursor. An electrolysis method characterized by electrolyzing an aqueous alkali chloride solution in an electrolytic cell that is divided into an anode chamber and a cathode chamber with the surface facing the anode side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13596079A JPS5662976A (en) | 1979-10-23 | 1979-10-23 | Electrolyzing method of aqueous alkali chloride solution |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13596079A JPS5662976A (en) | 1979-10-23 | 1979-10-23 | Electrolyzing method of aqueous alkali chloride solution |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5662976A JPS5662976A (en) | 1981-05-29 |
| JPS6211074B2 true JPS6211074B2 (en) | 1987-03-10 |
Family
ID=15163861
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13596079A Granted JPS5662976A (en) | 1979-10-23 | 1979-10-23 | Electrolyzing method of aqueous alkali chloride solution |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5662976A (en) |
-
1979
- 1979-10-23 JP JP13596079A patent/JPS5662976A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5662976A (en) | 1981-05-29 |
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