Diphenylmethane diisocyanate → Benzylbenzene diisocyanate

HRID 1247873Notes

Reaction equation

HRID 1247873 reaction equation
C(P(CCCC)CCCC)CCC.[CH:14]1[C:19]([CH2:20][C:21]2[CH:26]=[CH:25][C:24]([N:27]=[C:28]=[O:29])=[CH:23][CH:22]=2)=[CH:18][CH:17]=[C:16](N=C=O)[CH:15]=1>C1(C)C=CC=CC=1>[N-:27]=[C:28]=[O:29].[N-:27]=[C:28]=[O:29].[C:19]1([CH2:20][C:21]2[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=2)[CH:14]=[CH:15][CH:16]=[CH:17][CH:18]=1

Participants

4

Reactant 2

HCID 7570Diphenylmethane diisocyanateHCID 13831Tributylphosphine

Product 1

HCID 19824838Benzylbenzene diisocyanate

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

1.5 g of tributyl phosphine were added at room temperature to a solution of 1,000 g (4.0 mols) of diphenylmethane-4,4'-diisocyanate (MDI) in 2,000 g of toluene. After a short time, the dimeric MDI separated out of the solution and the temperature gradually rose to from 30° to 35° C. The reaction mixture was stirred for an additional 4 hours and the dimerization catalyst was then stopped by adding 1.5 g of toluene sulfonic acid methyl ester. The solid MDI "dimer" which formed was filtered by suction. After drying for about 5 hours at from 70° to 80° C., about 800 g of MDI "dimer" were obtained in the form of a fine powder. This powder was insoluble in practically all solvents. The decomposition point was above 250° C.

Workup

  1. customAfter a short time, the dimeric MDI separated out of the solution
  2. customgradually rose to from 30° to 35° C
  3. additionby adding 1.5 g of toluene sulfonic acid methyl ester
  4. customThe solid MDI "dimer" which formed
  5. filtrationwas filtered by suction
  6. customAfter drying for about 5 hours at from 70° to 80° C., about 800 g of MDI "dimer"
  7. customwere obtained in the form of a fine powder

Sources & evidence

ORD record
ord-a8cf6614ddf54d5c83a40c8880491ffa
Source dataset
uspto-grants-1985_06
Patent number
US04521338

Reaction notes

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