Reaktion #934011

Reaktionsgleichung

Dimethyl 3,4'-biphenyldicarboxylate

dimethyl 4,4'-biphenyldicarboxylate

→

ethylene 4,4'-biphenyldicarboxylate

Lösungsmittel

ethylene glycol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeequipped with a paddle stirrer
2. 2
   Temperatur15-cm heated
3. 3
   workup.DISTILLATIONVigreaux column, distillation head, condenser
4. 4
   SonstigeThe apparatus is evacuated
5. 5
   workup.ADDITIONrefilled with nitrogen three times
6. 6
   SonstigeA molten salt bath preheated to 220° C.
7. 7
   Temperaturis raised around the flask
8. 8
   SonstigeThis takes 41 minutes
9. 9
   workup.DISTILLATIONDuring this time, 6.9 mL of distillate is collected
10. 10
    SonstigeOver the next 34 minutes
11. 11
    Temperaturthe temperature is raised to 321° C
12. 12
    workup.DISTILLATIONThe excess ethylene glycol is distilled
13. 13
    workup.WAITAfter an additional 10 minutes
14. 14
    Sonstigeis 280° C.

Vorschrift

Dimethyl 3,4'-biphenyldicarboxylate (6.00 g, 0.0222 mole), 18.00 g (0.0666 mole) of dimethyl 4,4'-biphenyldicarboxylate, 12.83 g of ethylene glycol and 20 μL of titanium tetraisopropoxide are added to a 100 mL round bottom flask equipped with a paddle stirrer, 15-cm heated Vigreaux column, distillation head, condenser and graduated receiver. The apparatus is evacuated and refilled with nitrogen three times. A molten salt bath preheated to 220° C. is raised around the flask. After 2 hours, the temperature is slowly increased to 280° C. This takes 41 minutes. During this time, 6.9 mL of distillate is collected. Over the next 34 minutes, the pressure is slowly reduced to 1 mm of Hg and the temperature is raised to 321° C. The excess ethylene glycol is distilled. After an additional 10 minutes, the reaction mass is a viscous clear polymeric melt and the polymerization is stopped. As the molten polymer cools, it solidifies to an opaque off-white solid. The polymer is ground to a course powder in a centrifugal mill. Its inherent viscosity is 1.47 dL/g and its peak melting point as determined by differential scanning calorimetry is 280° C.

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