Ethylhexyl in real life

As a bit of a “purist”, I’ve always had a mild aversion to 2-ethylhexyl substituents in my molecules, as it has an undefined stereogenic center at the 2 position. Molecules incorporating such a functionality thus are random mixtures(!) of (R)- and (S)-stereoisomers, not to mention molecules possessing multiple 2-ethylhexyl substituents.

For material scientists, particularly aromatic polymer chemists, however, 2-ethylhexyl is a go-to choice for boosting solubility, as its bulky nature effectively disrupts π-stacking and aggregation. What’s really striking is how ubiquitous 2-ethylhexyl-containing molecules are in our daily lives, far beyond the confines of research labs. It makes me wonder if their widespread use also hinges on their aggregation-modulating properties.

Just to name a few common examples:

• 2-ethylhexyl nitrate (2-EHN) is a crucial cetane improver for diesel fuels.
• Bis(2-ethylhexyl) phthalate, produced at about 3 billion kg/year, is a primary plasticizer for PVC.
• Octocrylene and octyl methoxycinnamate are key ingredients in sunscreen products, vital for absorbing UVB and UVA radiation.

Without a doubt, I should have given 2-ethylhexyl much more credit!