Formaldehyde → Benzoxazines

HRID 615915Notes

Reaction equation

HRID 615915 reaction equation
[C:1]1([OH:7])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH2:8](N)[CH2:9][NH2:10].C=O>C(Cl)Cl>[O:7]1[C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=2[CH:8]=[CH:9][NH:10]1

Participants

5

Reactant 3

HCID 712Formaldehyde2×HCID 996PhenolHCID 3301Ethylenediamine

Product 1

HCID 17845026Benzoxazines

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
30 °C

Procedure

To a suitably equipped glass resin reactor equipped with stirrer is charged 450 parts phenol, 450 parts methylene chloride and 144 parts of ethylene diamine. The temperature of the reaction mixture is adjusted to 25° C. and 595 parts of 50% formalin is added while maintaining the temperature below 30° C. The reaction mixture is stirred for 2 hours at 30° C. after formaldehyde addition is complete. The reaction mixture is heated to atmospheric reflux and refluxed for 3 hours. The reaction mixture is allowed to cool and separate into two layers. The upper water layer is withdrawn and discarded. The lower organic layer is reheated to atmospheric reflux and distilled to remove solvent. Heating is continued with the gradual application of vacuum until a temperature of 70° C. at about 5.0 kPa pressure is reached. The very viscous product is removed from the reactor and allowed to cool. The light yellow semi-solid product has 67% closed dihydrobenzoxazine ring. Upon standing, the clear amorphous product slowly crystallizes to an opaque, grainy solid.

Workup

  1. customTo a suitably equipped glass resin reactor equipped with stirrer
  2. customis adjusted to 25° C.
  3. temperaturewhile maintaining the temperature below 30° C
  4. temperatureThe reaction mixture is heated
  5. temperatureto atmospheric reflux
  6. temperaturerefluxed for 3 hours
  7. temperatureto cool
  8. customseparate into two layers
  9. customThe upper water layer is withdrawn
  10. temperatureto atmospheric reflux
  11. distillationdistilled
  12. customto remove solvent
  13. temperatureHeating
  14. customis continued with the gradual application of vacuum until a temperature of 70° C. at about 5.0 kPa pressure
  15. customThe very viscous product is removed from the reactor
  16. temperatureto cool
  17. customclosed dihydrobenzoxazine ring
  18. customthe clear amorphous product slowly crystallizes to an opaque, grainy solid

Sources & evidence

ORD record
ord-0bcb665b315c4e369ef53db12425f06b
Source dataset
uspto-grants-1985_02
Patent number
US04501864

Reaction notes

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