Methyl isocyanate measurement

CH3NCO (liq.) Lemoult9 measured the heat of combustion of liquid methyl isocyanate. 

This paper describes a procedure for measuring the exposure of personnel to methyl isocyanate (MIC) in air in the occupational environment. The ion exchange adsorbent, together with the high-performance liquid chromatographic procedure as written, is capable of detecting 238 ng of MIC per milliliter. This is equivalent to 0.01 parts per million in a 15-liter air sample volume. 

On December 26, 1984 at 11 30 p.m, when the people of Bhopal, India, were preparing for sleep, a worker detected a water leak in a storage tank containing methyl isocyanate (MIC) at the Union Carbide Plant. About 40 tons of MIC poured from the tank for nearly 2 hours without any preventive measures being taken. The night winds carried the MIC into the city of Bhopal. Some estimates report 4000 people were killed, many in their sleep and as many as 400,000 more were injured or affected. 

The sensitivity of the helical preference of polyisocyanates to small chiral influences is also observed in chiral solvents. Poly(n-hexyl isocyanate) was found experimentally to have a persistence length of 20— 40 nm depending on the solvent in which the measurements were carried out.66 It was hypothesized that in more polar solvents a local interaction of the solvent would give rise to larger torsional oscillations around the backbone bonds. It was indeed observed that dissolution of poly(n-hexyl isocyanate) in non-racemic chiral solvents, e.g., (5)-l-chloro-2-methyl-butane, changed the persistence length and in addition also resulted in an excess of one helical sense.67 The chiral bias favoring one helical sense by itself is miniscule, but due to the cooperativity, a chiral preference is observed. More recently it was noted that the circular dichroism of these polymers decreases upon the addition of an achiral or racemic... 

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