Development of alkali-stable membranes functionalized with N,N-diphenyl carbazolium cations
(2022) KEMR30 20212Department of Chemistry
- Abstract
- N,N-diphenyl carbazolium salt has attracted interest for applications in anionic exchange membranes (AEM) due to its structural features and the high chemical stability that the compound exhibit. AEM are polymeric membranes with positively charged functional groups. They can be employed as electrolytes in alkaline fuel cells. In this project, different types of N,N-diphenyl carbazolium compounds were synthesized in a three step route. Hydrogenation of nitrobenzene to aniline, followed by an Ullmann cross-coupling and an intramolecular cyclization of a diazonium salt, gave the N,N-diphenyl carbazolium compounds. With a focus on developing novel anionic exchange membranes, new types of polymers based on N,N- diphenyl carbazolium salt were... (More)
- N,N-diphenyl carbazolium salt has attracted interest for applications in anionic exchange membranes (AEM) due to its structural features and the high chemical stability that the compound exhibit. AEM are polymeric membranes with positively charged functional groups. They can be employed as electrolytes in alkaline fuel cells. In this project, different types of N,N-diphenyl carbazolium compounds were synthesized in a three step route. Hydrogenation of nitrobenzene to aniline, followed by an Ullmann cross-coupling and an intramolecular cyclization of a diazonium salt, gave the N,N-diphenyl carbazolium compounds. With a focus on developing novel anionic exchange membranes, new types of polymers based on N,N- diphenyl carbazolium salt were synthesized using Yamamoto cross-coupling and superacid- mediated polyhydroxyalkylation reactions, respectively.
After synthesizing the monomers, two different routes were employed to continue the synthesis of the polymers. One of the polymers was prepared through a Yamamoto nickel-mediated polycondensation reaction. The reaction was investigated with and without a comonomer. Polymers with higher molecular weight were formed through copolymerization rather than homopolymerization. The second route involved polymerization through superacid-mediated polyhydroxyalkylation. Based on the results, one can conclude that the amount of catalyst needs to be high in order to prevent elimination, which inhibits polymerization. By increasing the catalyst amount, however crosslinking became an issue.
AEMs-functionalized with N,N-diphenyl carbazolium are hitherto unexplored. In this project, much usefull data were generated, giving the best possible conditions for further development. (Less) - Popular Abstract (Swedish)
- Växthuseffekten är ett av de största miljöproblemen som mänskligheten står inför. Den naturliga växthuseffekten är nödvändig för allt liv på jorden, men när växthusgaserna i atmosfären ökar på grund av CO2 utsläpp, stiger jordens medeltemperatur. Konsekvenserna av uppvärmningen är bland annat smältande isar, vattenbrist och naturkatastrofer. En av orsakerna till uppvärmningen är framför allt förbränning av fossila bränslen.
För att minska den globala uppvärmningen är det avgörande att ersätta de fossila bränslena med mer miljövänliga och hållbara alternativ. En av dessa är bränslecellen. En bränslecell är en effektiv energiomvandlare som omvandlar kemisk energi till elektricitet. I denna cell tillförs bränsle (exempelvis vätgas) och en... (More) - Växthuseffekten är ett av de största miljöproblemen som mänskligheten står inför. Den naturliga växthuseffekten är nödvändig för allt liv på jorden, men när växthusgaserna i atmosfären ökar på grund av CO2 utsläpp, stiger jordens medeltemperatur. Konsekvenserna av uppvärmningen är bland annat smältande isar, vattenbrist och naturkatastrofer. En av orsakerna till uppvärmningen är framför allt förbränning av fossila bränslen.
För att minska den globala uppvärmningen är det avgörande att ersätta de fossila bränslena med mer miljövänliga och hållbara alternativ. En av dessa är bränslecellen. En bränslecell är en effektiv energiomvandlare som omvandlar kemisk energi till elektricitet. I denna cell tillförs bränsle (exempelvis vätgas) och en oxidant (luftsyre). Bränslet oxideras vid anoden och oxidanten reduceras vid katoden. Mellan anoden och katoden befinner sig elektrolyten som vanligtvis är ett polymembran med jonbytaregenskaper.
Ett membran består av stora molekyler sammansatta av mindre molekyler. Detta membran har förmågan att binda joner samt uppvisa ledningsförmåga för jonerna. För att membranet ska ha god ledningsförmåga måste den molekylära strukturen uppfylla kraven som ställs av applikationen. Det är dock en stor utmaning att tillverka strukturer som är både effektiva och stabila över tid i den aggressiva miljön i bränslecellen. Genom att tillverka nya typer av strukturer kan deras egenskaper analyseras och optimeras för applikationer i framtida bränsleceller.
Fokus i detta projekt är en ny klass av joniska grupper med mycket hög kemisk stabilitet. Den kemiska syntesen utgör dock en stor utmaning. I projektet har en serie av dessa joner framställts och karakteriserats. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9087956
- author
- Mitrovic, Isabell LU
- supervisor
- organization
- course
- KEMR30 20212
- year
- 2022
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Organic chemistry, Anion exchange membrane, Anion exchange membrane fuel cell, Alkaline stability, Synthetic strategy, Quaternary ammonium salt
- language
- English
- id
- 9087956
- date added to LUP
- 2022-06-30 09:25:06
- date last changed
- 2022-06-30 09:25:06
@misc{9087956,
abstract = {{N,N-diphenyl carbazolium salt has attracted interest for applications in anionic exchange membranes (AEM) due to its structural features and the high chemical stability that the compound exhibit. AEM are polymeric membranes with positively charged functional groups. They can be employed as electrolytes in alkaline fuel cells. In this project, different types of N,N-diphenyl carbazolium compounds were synthesized in a three step route. Hydrogenation of nitrobenzene to aniline, followed by an Ullmann cross-coupling and an intramolecular cyclization of a diazonium salt, gave the N,N-diphenyl carbazolium compounds. With a focus on developing novel anionic exchange membranes, new types of polymers based on N,N- diphenyl carbazolium salt were synthesized using Yamamoto cross-coupling and superacid- mediated polyhydroxyalkylation reactions, respectively.
After synthesizing the monomers, two different routes were employed to continue the synthesis of the polymers. One of the polymers was prepared through a Yamamoto nickel-mediated polycondensation reaction. The reaction was investigated with and without a comonomer. Polymers with higher molecular weight were formed through copolymerization rather than homopolymerization. The second route involved polymerization through superacid-mediated polyhydroxyalkylation. Based on the results, one can conclude that the amount of catalyst needs to be high in order to prevent elimination, which inhibits polymerization. By increasing the catalyst amount, however crosslinking became an issue.
AEMs-functionalized with N,N-diphenyl carbazolium are hitherto unexplored. In this project, much usefull data were generated, giving the best possible conditions for further development.}},
author = {{Mitrovic, Isabell}},
language = {{eng}},
note = {{Student Paper}},
title = {{Development of alkali-stable membranes functionalized with N,N-diphenyl carbazolium cations}},
year = {{2022}},
}