Formaldehyde → Dihydrobenzoxazine

HRID 637622

Reaction equation

HRID 637622 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[CH2:8][CH2:9][NH:10]1

Participants

5

Reactant 3

HCID 712Formaldehyde2×HCID 996PhenolHCID 3301Ethylenediamine

Product 1

HCID 21887592Dihydrobenzoxazine

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. It is then heated to atmospheric reflux, refluxed for 3 hours and 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 The upper water layer is withdrawn and discarded.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 reduction of pressure until a temperature of 70° C. at about 5.0 kPa pressure is reached. Cellosolve (450 parts) is added to the resin slowly, keeping the temperature near 70° C. A uniform yellow solution forms which is cooled and filtered. The product has 66% closed dihydroxybenzoxazine ring and a calculated equivalent wt. of 224. The solution has a solids content of 60.2%.

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. temperatureIt is then heated to atmospheric reflux
  5. temperaturerefluxed for 3 hours
  6. temperatureto cool
  7. customseparate into two layers
  8. customThe upper water layer is withdrawn
  9. temperatureto atmospheric reflux
  10. distillationdistilled
  11. customto remove solvent
  12. temperatureHeating
  13. customis continued with the gradual reduction of pressure until a temperature of 70° C. at about 5.0 kPa pressure
  14. additionCellosolve (450 parts) is added to the resin slowly
  15. customnear 70° C
  16. temperatureA uniform yellow solution forms which is cooled
  17. filtrationfiltered
  18. customclosed dihydroxybenzoxazine ring

Sources & evidence

ORD record
ord-c6d41f2a57e145e2b99342d8965db9c0
Source dataset
uspto-grants-1985_12
Patent number
US04557979

Linked notes

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