Phenyl isocyanate explained

Phenyl isocyanate is an organic compound typically abbreviated PhNCO. The molecule consists of a phenyl ring attached to the isocyanate functional group. It is a colourless liquid that reacts with water. Phenyl isocyanate has a strong odor and tearing vapours, therefore it has to be handled with care.

Characteristic of other isocyanates, it reacts with amines to give ureas.^[1] Similarly, reacts with alcohols to form carbamates.

It is used in addition with triethylamine to activate nitro groups to undergo (C,O) 1,3-dipolar cycloaddition (as opposed to O,O). The nitro group (RCH₂NO₂) is converted to oxime-like dimers in the reaction:^[2]

4 PhNCO + 2 RCH₂NO₂ → 2(PhNH)₂CO + 2 CO₂ + (RCNO)₂

Structure

PhNCO is a planar molecule, according to X-ray crystallography. The N=C=O linkage is nearly linear. The C=N and C=O distances are respectively 1.195 and 1.173 Å.^[3]

External links

• Phenyl Isocyanate Data Sheet

Notes and References

1. Emmanuil I. Troyansky "Phenyl Isocyanate" in Encyclopedia of Reagents for Organic Synthesis, 2001 John Wiley & Sons
2. Mukaiyama . Teruaki . Hoshino . Toshio . The Reactions of Primary Nitroparaffins with Isocyanates . Journal of the American Chemical Society . 82 . 5339–5342 . 1960 . 20 . 10.1021/ja01505a017.
3. Porphyrin Sponges: Conservative of Host Structure in over 200 Porphyrin-Based Lattice Clathrates. Marianne P. Byrn . Carol J. Curtis . Yu Hsiou . Saeed I. Khan . Philip A. Sawin . S. Kathleen Tendick . Aris Terzis . Charles E. Strouse . J. Am. Chem. Soc.. 1993. 115. 21 . 9480–9497. 10.1021/ja00074a013.