Patent ID: 8034972

Claim:
A method for producing toluene diisocyanate, the method comprising: forming a mixture comprising phosgene gas and liquid toluene diamine; introducing the mixture into an external high shear device comprising at least one generator comprising a toothed rotor and a complementarily-shaped stator separated by a shear gap width in the range of from about 0.025 mm to about 10.0 mm to form a dispersion comprising phosgene gas bubbles dispersed in the toluene diamine liquid, wherein the gas bubbles have a mean diameter of less than 1 micron and wherein forming said dispersion comprises subjecting said mixture to a shear rate of greater than 20,000 s −1 and a local pressure of at least about 1034.2 MPa at said rotor tip; and subjecting the dispersion to phosgenation reaction conditions, whereby at least a portion of said toluene diamine is phosgenated to form product comprising toluene diisocyanate.