Polarity maps of bio-based solvents using Kamlet Abboud Taft solvatochromic parameters. Produced by the Green Chemistry Centre of Excellence at the University of York UK.

1. Typical
aprotic
solvents
Amines
Dipolar
aprotics
ChlorinatedHydrocarbon
Nitro
Ethers Ester Ketones
Nitriles
The polarity of bio-based solvents

2. Ionic
liquids
Acids
Alcohols Polyols
Typical
protic
solvents
The polarity of bio-based solvents

3. The Kamlet-Abboud-Taft solvatochromic parameters are measurements of solvent
polarity. Dipolarity (π*) and hydrogen bond accepting ability (basicity, β) can be drawn
on axes to create a polarity map. Instead of creating a three-dimensional plot with
hydrogen bond donating ability (acidity, α) included, protic and aprotic solvents are
separated onto separate charts for clarity.
There are many protic solvents derived from biomass. Alcohols and carboxylic acids
generally have only minor hazards. On the other hand, aprotic solvents can present
significant hazards and are not straightforward to replace. Bio-based aprotic solvents
tend to have unfamiliar structures in an attempt to convert bio-based chemicals into
useful solvents without the same hazardous functionality.