Probing the Pyrolysis of Guaiacol and Dimethoxybenzenes Using Collision-Induced Dissociation Charge-Remote...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Physical Chemistry

Background:

• Lignin's complex structure presents challenges for studying its thermal decomposition.
• Traditional pyrolysis methods can be confounded by secondary reactions, complicating pathway analysis.
• Understanding lignin model compound dissociation is crucial for biomass conversion technologies.

Purpose of the Study:

• To investigate the dissociation pathways of lignin model compounds using mass spectrometry.
• To evaluate collision-induced dissociation charge-remote fragmentation (CID-CRF) as a tool for studying lignin thermolysis.
• To compare CID-CRF dissociation pathways with those from gas-phase pyrolysis.

Main Methods:

• Utilized mass spectrometry combined with collision-induced dissociation charge-remote fragmentation (CID-CRF).
• Examined three lignin model compounds: guaiacol, and ortho- and meta-dimethoxybenzene, each with a remote sulfonate charge group.
• Analyzed dissociation products and compared fragmentation patterns to existing gas-phase pyrolysis data.

Main Results:

• CID-CRF induced dissociation of model compounds without direct involvement of the charge group.
• The primary dissociation event for all compounds was the loss of a methyl radical, forming phenoxy radicals.
• Observed differences in subsequent dissociation pathways compared to pyrolysis, attributed to altered dissociation barriers from the charged group.

Conclusions:

• CID-CRF is a powerful technique for elucidating lignin model compound thermolysis pathways.
• The method effectively minimizes secondary reactions, providing a cleaner fragmentation profile.
• This approach offers a more direct route to understanding lignin's thermal behavior.