Sodium Hydroxide → Tert-Butylhydroquinone

HRID 1866596Notes

Reaction equation

HRID 1866596 reaction equation
[OH-].C[N+](C)(C)C.[OH-].[Na+].CC(C1C=CC(O)=CC=1)(C1C=CC(O)=CC=1)C.[C:26]([C:30]1[CH:36]=[C:35]([OH:37])[CH:34]=[CH:33][C:31]=1[OH:32])([CH3:29])([CH3:28])[CH3:27]>>[C:26]([C:30]1[CH:36]=[C:35]([OH:37])[CH:34]=[CH:33][C:31]=1[OH:32])([CH3:29])([CH3:27])[CH3:28]

Participants

4

Reactant 3

HCID 14798Sodium Hydroxide4×HCID 60966Tetramethylammonium hydroxide2×HCID 131727822Bpa tbhq2×

Product 1

HCID 16043Tert-Butylhydroquinone

Conditions

Temperature
170 °C

Procedure

An 80/20 (mol/mol) polycarbonate copolymer of tert-butyl hydroquinone and BPA was made via the BMSC/melt reactive extrusion process. The samples were synthesized as follows. A stainless steel stirred tank reactor was charged with 6100 g BPA, 17767 g TBHQ, and 44971 g BMSC to give a molar ratio of [carbonate]/[diol] equal to about 1.017. Also added to the reactor was an aqueous catalyst solution of tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH) in an amount corresponding to 5.0×10−5 moles TMAH and 4.0×10−6 moles of NaOH per total number of moles of BPA/TBHQ. The reactor was then evacuated and purged with nitrogen three times to remove residual oxygen and then held at a constant vacuum pressure of 800 mbar. The reactor was then heated to 170° C. in order to melt and react the mixture. After approximately 4 hr 15 min from the start of heating (of the reactor tank), the reactor was pressurized with nitrogen to a constant overpressure of 0.9 bar, and the molten reaction mixture was fed through a 170° C. heat feed-line into an extruder at a rate of about 10 kg/h. 15 minutes before starting the feed to the extruder an aqueous catalyst solution of sodium hydroxide (NaOH) in an amount corresponding to 17.0×10−6 moles of NaOH per total number of moles of BPA/TBHQ. The extruder is a W&P ZSK25WLE 25 mm 13-barrel twin-screw extruder with an L/D-59. The feed into the extruder comprised a flash-valve to prevent boiling of the molten mixture. The reaction mixture was reactively extruded at a screw speed of 300 rpm. The extruder was equipped with five forward vacuum vents and one back-vent. The methyl salicylate byproduct is removed via devolatilization through these vents. The vacuum pressure of the back-vent was 11 mbar. The vacuum pressure of the first forward vent was 3 mbar. The vacuum pressure of the final four forward vents was less than 1 mbar. This TBHQ/BPA (80/20) copolymer has been made with all the extruder barrels at a temperature of 270° C. and the extruder die head at a temperature of 280° C. The polymer prepared had the following properties: Mw=37351; Mn=17019; and polydispersity=2.19.

Workup

  1. additionAlso added to the reactor
  2. customThe reactor was then evacuated
  3. custompurged with nitrogen three times
  4. customto remove residual oxygen
  5. customreact the mixture
  6. temperatureAfter approximately 4 hr 15 min from the start of heating (of the reactor tank), the reactor
  7. customthe molten reaction mixture
  8. customwas fed through a 170° C.
  9. temperatureheat feed-line into an extruder at a rate of about 10 kg/h
  10. custom15 minutes
  11. customThe extruder was equipped with five forward vacuum vents and one back-vent
  12. customThe methyl salicylate byproduct is removed via devolatilization through these vents
  13. customat a temperature of 270° C.
  14. customat a temperature of 280° C
  15. customThe polymer prepared

Sources & evidence

ORD record
ord-cdcf34beb0e9490e926b81023246e1a1
Source dataset
uspto-grants-2009_12
Patent number
US07629432B2

Reaction notes

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