... blue-green. The dye in strong sulfuric acid are yellow, diluted turned dark orange; In nitric acid in orange, dilute in orange after ... material, will first N, N 4-dimethylaniline and benzaldehyde sulfuric acid in the presence of condensation on, then by PbO2 oxidation ... Na2CO3 and have to dye alcohol SeJi, finally add oxalic acid crystal, the filter, dry to finished products..Pay attention: The ...