ISOCYANATES: METHOD 5522, Issue 2, dated 15 January 1998 - Page 6 of 6 APPENDIX: PREPARATION OF TRYPTAMINE DERIVATIVE Dissolve 0.00250 mole (0.41 g) of tryptamine (>99% purity) in 300 mL of toluene. Heat the solution to "60 C while stirring until much of the tryptamine is dissolved. Dissolve 0.001 mole (150-300 mg) of isocyanate in 20 mL of toluene. Add the isocyanate solution to the tryptamine solution. The tryptamine derivative will precipitate as a white gel. Collect the precipitate in a fritted-glass funnel by suction filtration. For the tryptamine derivatives of HDI and MDI, dissolve the precipitate in 100 mL (for HDI) or 450 mL (for MDI) of hot n-propanol. Filter the solution and allow it to cool. Collect the crystals. For the tryptamine derivatives of 2,4- and 2,6-TDI, dissolve the precipitate in 50 mL of hot n-propanol. Filter the solution and allow to cool. Add heptane (175 mL for 2,4-TDI and 100 mL for 2,6-TDI) and collect the precipitate in a fritted-glass funnel " by suction filtration. For all derivatives, dry in a vacuum oven at 60 C to remove solvent. TRYPTAMINE DERIVATIVES Diisocyanate
Tryptamine Derivative
MP ( C)
MW (g/mol)
2,4-TDI
2,4-TDI-tryptamine
216-219
494.60
2,6-TDI
2,6-TDI-tryptamine
298-301
494.60
MDI
MDI-tryptamine
~270
570.70
HDI
HDI-tryptamine
201-201.5
488.64
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
