Influence of nitrated alizarin on dyeing properties of polyester fabrics

3-nitroalizarin was prepared with bio-alizarin of hydroxyl anthraquinone structure as precursor under different nitration conditions,and the resultant nitrated product was characterized by FT-IR,HPLC-MS and 1H NMR.The nitrated alizarin was then used to dye superfine polyester fabrics.The levelness,soaping fastness,and color fastness to rubbing of the dyed samples were tested and compared with those of non-nitrated alizarin dyed samples.The results showed that the modified alizarin,i.e.3-nitroalizarin,can be obtained by reacting alizarin with concentrated nitric acid in glacial acetic acid at 40 ℃ for 8 h.The average purity of the product is 97%.When dyeing with non-nitrated alizarin,for obtaining good results,additives such as dispersing and penetrating agents have to be added to the dye-bath,however no auxiliary needs to be added when dyeing with nitrated alizarin and the levelness and color fastness to wet rubbing of its dyed fabric exhibit half rating higher than those of samples dyes with non-nitrated alizarin,thus reducing dyeing cost and wastewater pollution.