Page:NIOSH Manual of Analytical Methods - 5525.pdf/16

 ISOCYANAT ES, TOTA L (MAP): METHO D 5525, Issue 1, dated 15 March 2003 - Page 16 of 17

APPENDIX C: SYNTHESIS OF M AP DERIVATIVES Chem ical

MW

EQ. W T.

MAP Derivative MW

MAP Derivative EQ. W T.

MAP: 1-(9-Anthracenylmethyl)piperazine

276 .4

276 .4

HD I: Hex am ethylene diisocyanate

168 .2

84.1

721 .0

360 .5

TDI: Tolylene diisocyanate (toluene diisocyanate)

174 .2

87.1

727 .0

363 .5

MDI: 4,4'-Methylenebis(phenyl isocyanate)

250 .3

125 .2

803 .1

401 .6

HMD I: 4,4'-Methylenebis(cyclohexyl isocyanate)

262 .4

131 .2

815 .2

407 .6

MDI Trimer (MDI Triiso)

381 .4

127 .1

121 0.6

403 .5

IPD I: Isoph oron e diisocyanate

222 .3

111 .2

775 .1

387 .5

PhICN : Phe nyl isocyanate

119 .1

119 .1

395 .5

395 .5

BuICN : Butyl isoc yanate

99.1

99.1

375 .5

375 .5

318 .4

318 .4

AcMAP: Acetylated MAP

2 MAP + 1 diisocyanate yields 1 MAP-diisocyanate derivative 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Theoretical yield 1 meq: range from 360-408 m g. W eigh 1 m eq of d iisocyanate to fou r de cim al places. Dissolve in 10 m L of toluene. W eigh 1.2 meq of MAP (20% excess) to four decimal places. Dissolve in 20 mL of toluene. W hile stirring the M AP solution, add the diisocyanate solution dropw ise ov er a 1 0 to 15 m inute p eriod. Continue to stir for at least one ho ur. Tightly cover the solution and store overnight in the freezer to promote maximum precipitation. Us ing a B uec hne r funnel with filter pap er, filter the solution to collect the prec ipitate. W ash several times with small amounts of cold toluene to remove any remaining MAP. W ash several tim es with sm all am ounts of c old hexane to displace the toluene. Continu e to pull air throu gh the so lid for se vera l minutes to dry. Trans fer the solid derivative into a preweighed vial with T eflon cap. Using the vacuum pum p, apply vacuum until a stable weight is obtained.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition