Assertion: red dye alizarin | /r/HasProperty | isolated
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Source sentences:
text: In 1869, Perkin found a method for the commercial production from anthracene of the brilliant red dye alizarin, which had been isolated and identified from madder root some forty years earlier in 1826 by the French chemist Pierre Robiquet, simultaneously with purpurin, another red dye of lesser industrial interest, but the German chemical company BASF patented the same process one day before he did.