On the way to greener ionic liquids: Identification of a fully mineralizable phenylalanine-based ionic liquid

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

Over the past few decades ionic liquids (ILs) are increasingly seen as an important building block of green chemistry because of their specific properties as solvents, such as their potential for high recyclability, low volatility, low flammability, low toxicity, and their potential for synthesis from renewable resources. However, avoiding persistent or toxic cation/anion fragments is also urgently needed. In the best case they should be fully mineralizable by microorganisms after their release into the aquatic environment. The fragments fostering this can be determined by biodegradation studies, and the employment of identified readily biodegradable building blocks presents an innovation in the targeted design of green environmentally friendly ILs. The aim of this study was to improve the data-platform for the design of completely mineralizable ILs. Therefore the ready biodegradability of seven phenylalanine-based ILs and three non-ionic related compounds was investigated with a modified Closed Bottle test based on OECD guideline 301D. Liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS) analysis was used to identify the chemical structures of products resulting from incomplete biodegradation and transformation. Two kinds of degradation pathways were observed: the hydrolysis of an ethyl ester group or the hydrolysis of an amide bond and biodegradation of the released phenylalanine ethyl ester. Both degradation pathways resulted in persistent transformation products (TPs) with the exception of IL (4), a pyridinium substituted phenylalanine derived IL and the non-ionic deanol derivative (2a). IL (4) was ultimately biodegraded in the CBT after 42 days without leaving any TP. The biodegradation of compound (2a) was 78% after 42 days but resulted in a TP, which was readily biodegradable in a further CBT after a lag phase of 3 weeks, respectively. Even if both compounds were not "readily biodegradable" in the sense of the OECD guideline, particularly IL (4) can be proposed as a basic structure for sustainable and green ILs (benign by design) with the aim of optimizing its degradation rate further.

Original languageEnglish
JournalGreen Chemistry
Volume18
Issue number16
Pages (from-to)4361-4373
Number of pages13
ISSN1463-9262
DOIs
Publication statusPublished - 2016

DOI

Recently viewed

Publications

  1. Kontrolle, Ritus, Simulation
  2. Applying the HES-framework
  3. On the Epistemology of Computer Simulation
  4. Der Kunstraum
  5. Mythos
  6. Daniel Fiott (ed.), The csdp in 2020: The EU’s legacy and ambition in security and defence
  7. Geometria
  8. Introduction to Kant's Anthropology
  9. It's not regular TV
  10. Value co-creation through collective intelligence in the public sector
  11. Statement
  12. Water and soil towards sustainable land use
  13. Different sizes, similar challenges
  14. Normalitätskonstruktion und Selbstbilder erwachsener Reitender mit einer Körper- oder Sinnesbehinderung
  15. Challenges and opportunities in linking carbon sequestration, livelihoods and ecosystem service provision in drylands
  16. [U]topische Körper in der Adoleszenz
  17. What is Social Learning?
  18. Landscape moderation of biodiversity patterns and processes - eight hypotheses
  19. Germany
  20. Peacekeeping Operations in Outer Space
  21. Lesen unter Gleichen
  22. Wir sind ihr
  23. How Does Pre-Service Teachers’ Self-Efficacy Relate to the Fulfilment of Basic Psychological Needs During Teaching Practicum?
  24. 'Creativity and Innovation' in the Nineteenth Century
  25. Governance change and governance learning in Europe: stakeholder participation in environmental policy implementation
  26. Einleitung
  27. The mimicry of dialogue
  28. Finding one’s rhythm
  29. Improved dam operation in the Amu Darya river basin including transboundary aspects
  30. Teaching entrepreneurship as lived experience through ‘wonderment exercises’
  31. Possible future space debris mitigation and removal legal, regulatory and technical scenarios