Cyclopentanecarboxaldehyde trimer

Cyclopentanecarboxyaldehyde may trimerize if heating is prolonged hence a fast, simple distillation is done. When the distillation residue is cooled, a solid may appear. This solid can be distilled above 78° (100 mm.) as a clear liquid which solidifies when allowed to stand. Recrystallization of this material from 95% ethanol gives a white solid melting at 122-124°. This product was shown to be cyclopentanecarboxaldehyde trimer by... 

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