Hydrochloric Acid → 1,3-Diisopropylimidazolium chloride

HRID 1647021Notes

Reaction equation

HRID 1647021 reaction equation
[CH2:1]([NH2:4])[CH2:2]C.C=O.[CH:7]([NH2:10])([CH3:9])[CH3:8].[ClH:11].[CH:12](C=O)=O.[C:16]1([CH3:22])[CH:21]=CC=CC=1>O>[Cl-:11].[CH:7]([N+:10]1[CH:2]=[CH:1][N:4]([CH:16]([CH3:21])[CH3:22])[CH:12]=1)([CH3:9])[CH3:8]

Participants

8

Reactant 6

HCID 313Hydrochloric Acid2×HCID 712FormaldehydeHCID 1140Toluene2×HCID 6363IsopropylamineHCID 7852Propylamine2×HCID 7860Glyoxal2×

Product 1

HCID 112292421,3-Diisopropylimidazolium chlorideYield 102%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
4 °C

Procedure

Propylamine, 17.73 grams (0.3 mol), was added dropwise over 20 min. to a suspension of paraformaldehyde, 9.01 grams (0.3 mol), in 50 ml of toluene at such a rate that the temperature did not exceed 40° C. When the addition was complete, the mixture was stirred for an additional 10 min. The mixture was then cooled at 4° C. by means of an ice bath. Propylamine, 17.73 grams (0.3 mol), was added in a slow steady stream to the cooled mixture. When the second isopropylamine addition was complete, 50 ml of aqueous 6N HCl (0.3 mol) was added dropwise over 30 min. to the reaction mixture. By means of an ice bath, the reaction temperature was held below 25° C. When the HCl addition was complete, the ice bath was removed and the solution was warmed to 25° C. At this temperature, 43.53 grams (0.3 mol) of 40% aqueous glyoxal was added. When the glyoxal addition was complete the reaction mixture was stirred for an additional 1 h. An additional 45 ml of toluene was added to the reaction mixture and water, 78.18 grams, was removed from the reaction mixture by azeotropic distillation (Dean Stark trap) with the toluene. Removal of volatiles under vacuum yielded 58.02 grams (102% of theory) of 1,3-diisopropylimidazolium chloride. 1H NMR (CD3CN) of the material showed only resonances at δ 0.90 (t, 3JHH =7.4 Hz, 6 H); 1.88 (tt, 4 H); 4.27 (t, 3JHH =7.4 Hz, 4 H); 7.75 (d, 4JHH =1.6 Hz, 2 H); 9.47 (t, 4JHH, =1.6 Hz, 1 H) consistent with the desired product.

Workup

  1. customdid not exceed 40° C
  2. additionWhen the addition
  3. customBy means of an ice bath, the reaction temperature was held below 25° C
  4. customthe ice bath was removed
  5. temperaturethe solution was warmed to 25° C
  6. stirringwas stirred for an additional 1 h
  7. customwas removed from the reaction mixture by azeotropic distillation (Dean Stark trap) with the toluene
  8. customRemoval of volatiles under vacuum

Sources & evidence

ORD record
ord-6129ff19fdc842a4a37b5ded634e9309
Source dataset
uspto-grants-1993_01
Patent number
US05182405

Reaction notes

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