Formic acid is a relatively weak catalyst, but it is effective at low concentrations. It’s also relatively cheap and easy to handle. For these reasons, formic acid is a common catalyst for polyurethane formation.

The catalytic effect of formic acid on polyurethane is due to its ability to protonate isocyanate groups. This protonation makes the isocyanate group more reactive, making it easier to react with the hydroxyl group.

The catalytic effect of formic acid is also due to its ability to form hydrogen bonds with the carbamate intermediate. These hydrogen bonds stabilize the intermediate, making it easier to react with the hydroxyl group.

The catalysis of formic acid is important because it allows polyurethane formation at lower temperatures and shorter reaction times. This is beneficial for industrial applications where time and cost are important considerations.

Formic acid is also a safe catalyst. It is not a flammable or explosive material, nor does it produce any harmful by-products. For these reasons, formic acid is a common choice for catalyzing polyurethane formation.