Optimization of pendant chain length in partially fluorinated aromatic. anion exchange membranes for alkaline fuel cells

Transcription

1 Electronic Supplementry Mteril (ESI) for Journl of Mterils Chemistry A. This journl is The Royl Society of Chemistry 0 Supplementry Informtion ptimiztion of pendnt chin length in prtilly fluorinted romtic nion exchnge membrnes for lkline fuel cells Ahmed Mohmed Ahmed Mhmoud b nd Kenji Miytke*. en Energy Reserch Center, University of Ymnshi, Tked, Kofu 00-0, Jpn b. Chemistry Deprtment, culty of Science, Sohg University,, Sohg, Egypt.. Experimentl Mterils,-Dichlorobenzylbromide, dimethyl sulfte,,-dichlorobenzldehyde, potssium tert-butoxide (t-buk), (-crboxypropyl)triphenyphosphonium bromide, (- crboxybutyl)triphenyphosphonium bromide,, -bipyridine, -bromopropionic cid, trns-,-dichlorocinnmic cid, lithium luminum hydride (LAH), dimethyl mine hydrochloride, nd,-dichlorobenzylbromide were purchsed from TCI Inc. nd used s received. Dimethyl sulfoxide-d (DMS-d ) with 0.0% tetrmethylsilne (TMS) nd chloroform-d (CD ) with 0.0% TMS were purchsed from Acros rgnics nd used s received. Bis(,-cyclooctdiene)nickel(0) (Ni(cod) ), hydrochloric cid, potssium crbonte, potssium hydroxide, dimethyl sulfoxide (DMS), N,Ndimethylformmide (DM), nhydrous lithium bromide, triethylmine, triphenylphosphine, sulfuric cid, cetic cid, potssium cynide, potssium crbonte, dichloromethne, cetonitrile, diethyl ether, N,N-dimethylcetmide (DMAc), nd tetrhydrofurn (TH) were purchsed from Knto chemicl Co. nd used s received. Plldium-ctivted crbon (0% Pd) ws purchsed from Wko chemicls nd used s received. S

2 Synthesis of,-dichlorophenyl monomers Synthesis of (,-dichlorophenyl)cetonitrile (A) A 00 ml round bottomed flsk ws chrged with,-dichlorobenzylbromide (.00 g, 0.0 mmol) nd ethnol ( ml). To the solution, ml of queous potssium cynide (. g,.0 mmol) solution ws slowly dded. The mixture ws refluxed for h. A white solid of potssium chloride ws formed within few minutes. After the complete rection (checked by TLC), the mixture ws filtered quickly to remove the slts nd then, the filtrte ws llowed to cool nd precipitte white solid. The crude product ws filtered nd purified by sublimtion in vcuum t 0 ºC to obtin A s white crystl (. g, % yield). Synthesis of (,-dichlorophenyl)cetic cid (A). In 00 ml round bottomed flsk, A (. g,.0 mmol) ws dded to ml of sulfuric cid, cetic cid, nd wter (:: by volume). The mixture ws refluxed for overnight. The mixture ws llowed to cool to room temperture to precipitte white solid. The crude product ws collected by filtrtion, wshed with distilled wter severl times, nd dried under vcuum to obtin A s n off-white solid (. g, % yield) Synthesis of -(,-dichlorophenyl)-n,n-dimethylcetmide (A) A 00 ml round bottomed flsk ws chrged with A (. g,. mmol) nd 0 ml of dichloromethne. To the solution, oxlyl chloride (. ml,.0 mmol) in ml of dichloromethne ws dded dropwise. The mixture ws stirred t room temperture for h nd cooled with n ice bth. To the mixture, dimethyl mine hydrochloride (.g,.0 mmol) nd trimethylmine (.00 ml,.0 mmol) were slowly nd successively dded. The mixture ws llowed to wrm t room temperture nd stirred for h. After the completion rection, the mixture ws wshed with distilled wter, M H, sturted NHC, nd distilled wter severl times. The combined orgnic lyers were dried over MgS nd evported under vcuum. The crude product ws purified on silic gel column chromtogrphy (hexne:ethyl cette = 9: s eluent) to obtin A s yellow liquid (.0 g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylethn--mine (A) A 00 ml round bottomed flsk ws chrged with LAH (0. g,. mmol) nd 0 ml of TH under nitrogen tmosphere. The mixture ws cooled with n ice bth followed by slow ddition of A (.0 g,. mmol) solution in 0 ml of TH. The mixture ws heted t 90 ºC. After the complete rection, the mixture ws llowed to cool to room S

3 temperture nd quenched crefully by dropwise ddition of 0. ml of wter nd 0. ml of % NH q. Then,. ml of wter nd 0 ml of TH were dded to the mixture to precipitte solid. The filtrte ws evported under vcuum nd the residue ws purified by lumin column chromtogrphy (hexne:ethyl cette = 9: s eluent) to obtin A s colorless liquid (.00 g, 9% yield). Synthesis of -(,-dichlorophenyl)-n, N-dimethylprop--enmide (B) Using the sme procedure for A, trns-,-dichlorocinnmic cid. (.00 g, 9.00 mmol) ws midted to obtin B (.0 g, 9% yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylpropnmide (B) A 0 ml round bottomed flsk equipped with hydrogen gs inlet/outlet ws chrged with B (.0 g, 0.0 mmol) nd 00 ml of ethyl cette. To the mixture ws dded Pd-C powder (. g). Hydrogen gs ws bubbled through the rection mixture for h. Then, the ctlyst ws removed by filtrtion nd the filtrte ws evported under vcuum. The crude product ws purified by silic gel column chromtogrphy (hexne: ethyl cette = 9: s eluent) to obtin B (.90 g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylpropn--mine (B) Using the sme procedure for A, B (.90 g,. mmol) ws reduced with LAH to obtin B (.0 g, 9% yield). Synthesis of (-crboxyethy)triphenylphosphonium bromide (C) A 00 ml round bottomed flsk ws chrged with -promopropionic cid (. g, 0.00 mmole) nd triphenylphosphine (. g, 0.00 mmol). The mixture ws heted under net conditions t 0 ºC. The mixture ws cooled to room temperture. The resulting viscous product ws wshed with cetonitrile/diethyl ether severl times to obtin C s white solid (.00 g, 00% yield). Synthesis of -(,-dichlorophenyl)but--enoic cid (C) nd -(,- dichlorophenyl)but--enoic cid (Cb) A 00 ml round bottomed ws chrged with C (.00 g, 9.0 mmol),,- dichlorobenzldehyde (.0 g,.9 mmol), nd ml dichloromethne. The suspended mixture ws cooled with n ice bth. To the mixture, t-buk (. g, 9.90 mmol) ws dded slowly in severl portions in h. The mixture ws stirred t room temperture for h. After the complete rection, the mixture ws wshed with M H nd M S

4 NHC, respectively, nd extrcted with ethyl cette severl times. The combined orgnic lyers were dried over MgS nd evported under vcuum. The crude product ws purified by silic gel column chromtogrphy (hexne: ethyl cette = 9: s eluent) to obtin mixture of C nd Cb s ple yellow liquid (0. g, % yield). Synthesis of -(,-dichlorophenyl)-butnoic cid (C) Using the sme procedure for B, C nd b (.90 g, 9.00 mmol) were hydrogented to obtin C s colorless liquid (.00 g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylbutnmide (C) Using the sme procedure for A, C (.00 g,.9 mmol) ws midted to obtin C (.0 g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylbutn--mine (C) Using the sme procedure for A, C (.g, 0.0 mmol) ws reduced with LAH to obtin C s ple yellow liquid (.0 g, 9% yield). Synthesis of -(,-dichlorophenyl)pent--enoic cid (D) In L round bottomed flsk, (-crboxypropyl)triphenyphosphonium bromide (.0 g, 9.9 mmol) ws dissolved in 00 ml of TH. To the solution, ml of M t- BuK solution in TH ws dded dropwise t 0 ºC. The mixture ws stirred t 0 ºC for h. T the mixture,,-dichlorobenzldehyde (.00 g,.0 mmol) solution in 00 ml of TH ws dded dropwise. Sme work-up s tht for C fforded D s colorless liquid (.90 g, 9% yield). Synthesis of -(,-dichlorophenyl)pentnoic cid (D) Using the sme procedure for B, D (. g, 9.00 mmol) ws hydrogented to obtin D (. g, 9% yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylpentnmide (D) Using the sme procedure for B, D (. g,.0 mmol) ws midted to obtin D (.99 g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylpentn--mine (D) Using the sme procedure for A, D (.99 g, 9. mmol) ws reduced with LAH to S

5 obtin D (.0 g, % yield). Synthesis of -(,-dichlorophenyl)hex--enoic cid (E) Using the sme procedure for C, (-crboxybutyl)triphenyphosphonium bromide (. g, 0 mmol) ws rected with,-dichlorobenzldehyde (.0 g,.0 mmol) to obtin E (. g, % yield). Synthesis of -(,-dichlorophenyl)hexnoic cid (E) Using the sme procedure of B, E (. g,.9 mmol) ws hydrogented to obtin E (.0 g, 99% yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylhexnmide (E) Using the sme procedure for B, E (.0 g,. mmol) ws midted to obtin E (. g, % yield). Synthesis of -(,-dichlorophenyl)-n,n-dimethylhexn--mine (E) Using the sme procedure for A, E (. g,. mmol) ws reduced with LAH to obtin E (.0 g, 0% yield). Synthesis of PA-Cx copolymers A typicl procedure for PA-C (m:n =.00 : 0.9) is s follows. A 00 ml round bottomed flsk equipped with reflux condenser, mgnetic stirrer, nd nitrogen inlet-outlet ws chrged with perfluoromonomer (.0 g,.00 mmol), B (0. g,.90 mmol),, -biyridine (. g,.0 mmol), ml of DMAc, nd ml of toluene. The mixture ws refluxed t 0 ºC for h for zeotropic removl of wter. The mixture ws llowed to cool to 0 ºC, to which Ni(cod) (. g,.0 mmol) ws dded. The mixture ws stirred for h t 0 ºC, cooled to room temperture, nd poured dropwise into lrge excess of methnol to precipitte blck solid. The crude product ws collected by filtrtion, wshed with M H, sturted potssium crbonte, nd ultrpure wter severl times to obtin PA-C s yellowish brown solid (0.9 g, 90% yield). Quterniztion rection A typicl procedure is s follows. In 00 ml glss vil, 0. g of PA-C copolymer ws dissolved in 0 ml of DMAc. To the solution, dimethyl sulfte ( equimolr to dimethyl mino groups) ws dded. The mixture ws stirred for h t room S

6 temperture. The mixture ws poured dropwise into lrge excess of wter to precipitte white solid. The product ws collected by filtrtion nd dried under vcuum t 0 ºC to obtin QPA-C copolymer in methylsulfte ion form (0. g, 00% yield). Membrne preprtion A typicl procedure is s follows. QPA-C (0. g) ws dissolved in ml of NMP nd cst onto flt glss plte t 0 ºC to obtin flexible nd trnsprent QPA-C membrne ( μm thick). Ion exchnge rection i) To chloride ion form Membrnes in methylsufte ion forms were immersed in M H for h nd wshed with ultrpure wter severl times until the residul wter becme neutrl. Membrnes in chloride ion forms were used for titrtion nd mechnicl properties mesurements. ii) To hydroxide ion form Membrnes in methylsulfte ion forms were immersed in M KH t 0 ºC for h nd wshed severl times with degssed ultrpure wter until the residul wter becme neutrl. Membrne in hydroxide ion forms were used for hydroxide ion conductivity nd stbility mesurements. Mesurements Dichloromonomers, PA-Cx copolymers, nd QPA-Cx membrnes were chrcterized by H nd 9 NMR spectr on JEL JNM-ECA/ECX00 using CD or DMS-d s solvents nd TMS s n internl reference. The moleculr weight (M w, M n, M w /M n ) ws determined by gel permetion chromtogrphy using Shodex K-0L column nd Jsco 0 UV detector (0 nm) with CH contining 0.0 M triethylmine s eluent. Stndrd polystyrene smples were used for clibrtion. Ion exchnge cpcity (IEC) vlues of the membrnes were determined by Mohr titrtion method. or wter uptke mesurement, membrnes in hydroxide ion forms were dried in vcuum oven t 0 ºC for overnight nd weighed to obtin dry weights. The membrnes were then immersed in deionized wter for h, wiped quickly with pper to remove the surfce wter, nd weighed immeditely to obtin wet weights. In-plne hydroxide ion conductivity of the membrnes ws mesured using n AC impednce system (Solrtron B, Solrtron Inc.) in degssed nd deionized wter. Prior to the S

7 mesurement, the membrnes were immersed in M KH for t lest h to ensure complete ion exchnge rection, rinsed thoroughly with degssed nd deionized wter. The resistnces of the membrnes were mesured using four-probe conductivity cell. Trnsmission electron microscopic (TEM) imges nd dynmic mechnicl properties were mesured ccording to our previous work. SAXS profiles were obtined t 0 under humidified N tmosphere t 0-90% RH using Nno-Viewer (Rigku) nd Cu(Kα) s X-ry source. Tensile strengths ws investigted by Shimdzu AGS-J 00N universl test mchine equipped with Toshin Kogyo Bethel-A temperture nd humidity controllble chmber. Detiled procedure for these mesurements ws reported previously. - Alkline stbility test The membrnes in hydroxide ion forms were plced in conductivity mesurement cell nd the conductivity ws mesured s 0 h. The membrnes fixed in the conductivity cell were immersed in M, M or M KH queous solution t 0 ºC in closed vil for 000 h ( M nd M) or h ( M). At the set time, the membrnes were wshed with nd immersed in deionized wter for h prior to the conductivity mesurement t 0 ºC. After the stbility test, the membrnes were subjected to post-test NMR, TEM nd DMA nlyses. Preprtion of ctlyst coted membrne (CCM) nd fuel cell opertion A 0 wt% Pt-loded ctlyst (Pt/CB, TEC0E0E, Tnk Kikinzoku Kogyo) ws used for the cthode nd node sides. The ctlyst pste ws prepred from the Pt-loded ctlyst with QPA-C ionomer (IEC = 0.9 meq. g - ) s the binder s follows: In glss vil, mixture of Pt- ctlyst: ethnol: wter (:: by weight) ws stirred t 0 rpm for 0 minutes t room temperture. A.0 wt% solution of QPA-C (IEC = 0.9 meq. g - ) in ethnol ws dded to the Pt-ctlyst suspension nd the mixture ws stirred t 0 rpm for 0 min to obtin the ctlyst pste. The mss rtio of the dry binder to crbon blck (QPA-C ionomer/crbon) ws djusted to 0.. The CCM ws prepred by sprying the ctlyst pste onto both sides of QPA-C (. meq. g -, μm thick) membrne using pulse-swirl-spry pprtus. The Pt loding ws 0. ± 0.0 mg cm - with ctive geometric re of. cm. The CCM ws immersed in M KH for h then in deionized wter for h for ion exchnge rection. The CCM ws sndwiched between two gs diffusion lyers for min t MP nd ssembled into single cell consisting of two crbon seprtor pltes. The fuel cell ws operted t 0 ºC under n mbient pressure with fully humidified H nd. The flow rte ws 00 ml min - for S

8 both H nd. The high-frequency resistnce (HR) of the cell ws mesured with Kikusui C impednce meter t.0 khz. S

9 Schemes nd igures Br KCN EtH CN A i) Hydrolysis CH A ii) Chlorintion iii) Amidtion iv) Red. N N A A Scheme S. Synthesis of -(,-dichlorophenyl)-n,n-dimethylethnmine.,+ch,+ch, +CH CH igure S. H NMR spectr of A, A, A, nd A. S9

10 i) (C) H N Pd-C / H ii) (CH ) NH.H TEA B B N LiAlH N B Scheme S. Synthesis of -(,-dichlorophenyl)-n,n-dimethylpropnmine.,+ch +CH H igure S. H NMR spectr of B nd B. S0

11 Br H Toluene + PPh Ph Ph P + Reflux Br - H Scheme S. Synthesis of (-crboxyethyl)triphenylphosphonium bromide. C (),, 0 CH 0 (b) igure S. () H nd (b) P NMR spectr of C. S

12 CH Ph Ph + P + Ph H t-buk/ TH C H + Cb ' ' ' H Pd-C/ H H C i) (C) ii) (CH ) NH.H/ TEA C N LiAlH TH N C Scheme S. Synthesis of -(,-dichlorophenyl)-n,n-dimethylbutnmine., + CH EA : ethylcette, + CH EA EA H, + CH EA EA EA CH ' ' EA ' EA (ppm) igure S. H NMR spectr of C, C, C, nd C. S

13 i) (C) CH ii) (CH ) NH.H TEA Ph Ph + P + Ph N D H ButK/ TH LiAlH TH 9 N D H D Pd-C/ H H D Scheme S. Synthesis of -(,-dichlorophenyl)-n,n-dimethylpentnmine.,+ch,9,+ch, +CH, +CH, (ppm) igure S. H NMR spectr of D, D, D, nd D. S

14 i) (C) CH ii) (CH ) NH.H TEA Br - Ph Ph + P + Ph N H LiAlH TH t-buk/ TH N H E Pd-C/ H H E E E Scheme S. Synthesis of -(,-dichlorophenyl)-n,n-dimethylhexnmine.,ch EA: ethylcette 9,0,CH 9, EA EA,CH, EA EA EA,CH igure S. H NMR spectr of E, E, E, nd E. S

15 b c PA-C m N n 9 (CH ) S DMAc / r.t b c QPA-C m N + 9 n CH S - H () - (CH ) S DMS 9 -, 9 H (ppm) (b) b,c b,c igure S. () H nd (b) 9 NMR spectr of PA-C in CD nd QPA-C in DMS-d. S

16 b c PA-C m n (CH ) S DMAc / r.t b c QPA-C m n 9 N 9 N CH S - () - H + - CH S 9 0 DMS - CH 0 H,9 (b) b,c b,c igure S. () H nd (b) 9 NMR spectr of PA-C in CD nd QPA-C in DMS-d. S

17 b c PA-C m n (CH ) S DMAc / r.t b c QPA-C m n 9 0 N 9 0 N + CH S - () - H + - CH S 0 DMS,9 - CH,9,0 (b) b,c b,c igure S9. () H nd (b) 9 NMR spectr of PA-C in CD nd QPA-C in DMS-d. S

18 b c PA-C m n (CH ) S DMAc / r.t b c QPA-C m n N N + CH S - () + - CH S H DMS -,0 9 - CH - (b) b,c b,c igure S0. () H nd (b) 9 NMR spectr of PA-C in CD nd QPA-C in DMS-d. S

19 b c PA-C m n 9 0 (CH ) S DMAc / r.t b c QPA-C m n 9 0 N N + CH S - () - H + - CH S, 9,0 - CH 9,0,, (b) b,c b,c igure S. () H nd (b) 9 NMR spectr of PA-C in CD nd QPA-C in DMS-d. S9

20 igure S. of PA-Cx (the peks were for clrifiction). Absorbnce t 0 nm 9 0 Retention time (min) PA-C PA-C PA-C PA-C PA-C GPC profiles copolymers normlized QPA-C QPA-C igure S Bckground-subtrcted SAXS profiles for QPA-Cx (IEC =.9 meq. g - ) 0 - QPA-C nd QPA-C (IEC =. meq. g - QPA-C ) s function of QPA-C sctter vector (q) from 0% to 90% RH t 0 ºC. 0 - QPA-C q / nm - H - conductivity (ms/cm) intensity / counts d / nm 0 - QPA-C (. meq/g) QPA-CB (.00 meq/g) QPA-C (0.9 meq/g) QA-C (0.9 meq/g) QPA-C (.0 meq/g) Time (h) S0

21 igure S Alkline stbility of QPA membrnes in M KH t 0 ºC. The conductivity ws mesured t 0 ºC. H - conductivity (ms/cm) DMS.9... H M KH M KH M KH Time (h) igure S Alkline stbility of QPA-C (IEC =. meq. g - ) in M, M, nd M KH t 0 ºC. The conductivity ws mesured t 0 ºC DMS H Y : prts per Million : H X : prts per Million : H igure S Zoomed-in D CSEY NMR spectr of the pristine QPA-C (IEC =. meq. g - ) (green line) nd post-test QPA-C (brown line) membrnes fter 000 h in S

22 M KH t 0 in DMS-d. (b) b,c (ppm) igure S () H nd (b) 9 NMR spectr of QPA-C membrne (IEC =.0 meq. g - ) before nd fter the lkline stbility test in DMS-d. S

23 igure S TEM imges of the QPA-C (IEC = 0.9 meq. g - ) nd QPA-C (IEC =.0 meq. g - ) membrnes before nd fter the lkline stbility tests. Trnsition temperture ( o C) Number of crbon toms in the side chin (x) igure S9 Trnsition temperture in tn δ curves (igure 0) of QPA-Cx s function of number of crbon toms in the side chin (x). S

24 00 Elongtion t brek (%) Mx. Stress (MP) Numberof crbon toms in the side chin (x) igure S0 Mximum stress nd elongtion t brek of QPA-Cx membrnes s function of number of crbon toms in the side chin (x). S

25 () (. meq/g), fter h QPA-C (. meq/g), 0h H 0 (b) (ppm) -0-0 igure S () H nd (b) 9 NMR spectr of QPA-C membrnes before nd fter the fuel cell durbility test t constnt current density (0.0 A cm - ). S

26 References () H. no, J. Miyke, S. Shimd, M. Uchid nd K. Miytke, J. Mter. Chem. A, 0,, 9-. () A. M. A. Mhmoud, A. M. M. Elsghier, K. tsuji nd K. Miytke, Mcromolecules, 0, 0,. () M. Hr, T. Kimur, T. Nkmur, M. Shimd, H. no, S. Shimd, K. Miytke, M. Uchid, J. Inuki nd M. Wtnbe, Lngmuir, 0,, 9-9. () A. M. A. Mhmoud, A. M. M. Elsghier nd K. Miytke, RSC Adv., 0,, -0. S