Hydrochloric Acid → Carbendazim

HRID 1973425Notes

Reaction equation

HRID 1973425 reaction equation
[N:1]#[C:2]N.Cl[C:5]([O:7][CH3:8])=[O:6].[OH-].[Na+].[C:11]1([NH2:18])[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=1[NH2:17].Cl>O>[N:17]1[C:12]2[CH:13]=[CH:14][CH:15]=[CH:16][C:11]=2[NH:18][C:2]=1[NH:1][C:5]([O:7][CH3:8])=[O:6]

Participants

7

Reactant 5

HCID 313Hydrochloric AcidHCID 6586Methyl chloroformateHCID 7243O-PhenylenediamineHCID 9864CyanamideHCID 14798Sodium Hydroxide

Product 1

HCID 25429Carbendazim

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
105 °C

Procedure

To a jacketed reactor equipped with feed ports stirrer, reflux condenser, and pH probe are added 32 parts of 50% cyanamide solution and 100 parts of water. Methyl chloroformate (41.1 parts) and 67 parts of 50% sodium hydroxide solution are changed concurrently so as to maintain the pH of the solution at 7 - 7.5 and the reacton temperature at 40° - 50° C. The solution is held at 50° C. for 45 minutes and then 36 parts of o-phenylenediamine is added. The pH of the solution is held at 3.9 to 4.1 by the gradual addition of 65 parts of 37% HCl. The solution is heated to 105° C. and held at this temperature for 30 minutes. During this hold time, the product starts to crystallize. The reaction mass is cooled to 25°-30° C. and the solid product is filtered, washed with water and acetone, and dried in the vacuum oven at 80° C. to give 59.6 parts of 2-benzimidazolecarbamic acid, methyl ester. This represents a product yield of 93.5% based on o-phenylenediamine.

Workup

  1. customTo a jacketed reactor equipped with feed ports stirrer
  2. temperaturereflux condenser
  3. temperatureto maintain the pH of the solution at 7 - 7.5
  4. customat 40° - 50° C
  5. waitheld at this temperature for 30 minutes
  6. customto crystallize
  7. temperatureThe reaction mass is cooled to 25°-30° C.
  8. filtrationthe solid product is filtered
  9. washwashed with water and acetone
  10. customdried in the vacuum oven at 80° C.

Sources & evidence

ORD record
ord-75ffc2733dfe4a06ada6e1a458cdfb7e
Source dataset
uspto-grants-1976_12
Patent number
US03997553

Reaction notes

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