Water → Diphenyl carbonate

HRID 1840654Notes

Reaction equation

HRID 1840654 reaction equation
[OH2:1].[OH-].[Na+].[C:4]1([OH:10])[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[C:11](Cl)(Cl)=[O:12]>C(Cl)Cl>[C:11](=[O:12])([O:1][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[O:10][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

6

Reactant 4

HCID 962WaterHCID 996Phenol3×HCID 6371PhosgeneHCID 14798Sodium Hydroxide4×

Product 1

HCID 7597Diphenyl carbonateYield 99.9%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
33 °C

Procedure

A mixture comprising 103 kg/hour of deionised water, 42.2 kg/hour 50% NaOH and 48.3 kg/hour phenol was continuously combined with a solution comprising 86.2 kg/hour methylene chloride and 27.5 kg/hour phosgene (8 mol % excess with respect to phenol) in a vertical, cooled tubular reactor. The reaction mixture was cooled to a temperature of 33° C., and a pH of 11.5 was measured after an average residence time of 15 seconds. 5.4 kg/hour of 50% NaOH were then added to said reaction mixture in the second step of the process, so that after a further residence time of 5 minutes the pH in the second reaction step was 8.5. In this continuously operated reaction, any fluctuations in the rates of addition which occurred were compensated for by adjusting the rate of addition of NaOH in each case. In the second step of the process, the reaction mixture was continuously mixed by passing it through a tube provided with constrictions. After the renewed addition of NaOH, the reaction temperature was adjusted to 30° C. by cooling. The aqueous, slightly alkaline phase contained 20 ppm phenol. The DPC yield was correspondingly high, namely 99.998% with respect to phenol. After separating the organic phase from the aqueous phase, the product was washed with 0.6% HCl and water, and 99.9% (as determined by GC) diphenyl carbonate was obtained after a final phase separation after removing the methylene chloride by evaporation.

Workup

  1. temperaturecooled tubular reactor
  2. customafter an average residence time of 15 seconds
  3. customreaction mixture in the second step of the process
  4. customso that after a further residence time of 5 minutes the pH in the second reaction step
  5. customIn this continuously operated reaction
  6. additionany fluctuations in the rates of addition which
  7. additionIn the second step of the process, the reaction mixture was continuously mixed
  8. customprovided with constrictions
  9. customwas adjusted to 30° C.
  10. temperatureby cooling
  11. customThe DPC yield
  12. customAfter separating the organic phase from the aqueous phase
  13. washthe product was washed with 0.6% HCl and water

Sources & evidence

ORD record
ord-c785d98c4ae742b38deebaee436e5990
Source dataset
uspto-grants-2004_01
Patent number
US06680400B2

Reaction notes

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