| Direct dyes have been used to dye cellulose for over 100 years. Due to the ease of their application and the wide gamut of products available at a modest cost, direct dyes are still a popular dye class. For many years, direct dyes included those made from benzidine and its analogs. Nowadays, it is well known that benzidine and its congeners are genotoxic diamines and dyes based on benzidine and its congeners can no longer be manufactured for textiles in the United States because of their carcinogenic potential. However, the commercial importance of dyes derived from benzidine and its congeners has led to the search for non-genotoxic alternatives.; This dissertation is concerned with the synthesis and evaluation of direct dyes in which the non-genotoxic diamines 2,2'-dimethyl-5,5 '-dipropoxybenzidine and 5,5'-dipropoxybenzidine are employed as potential alternatives to benzidine. The results of this study indicate that both diamines (I) can be used to prepare new direct dyes (II) having comparable colors and fastness properties to commercial direct dyes, and that the structures of the new direct dyes can be confirmed by negative ion electrospray mass spectrometry (ESMS).; It has been found that copper complexes of the new direct dyes can be synthesized, demonstrating that alkyl groups appreciably longer than methyl can be cleaved via interaction with CuSO4. However, due to the very low water solubility of the copper complexes, the application of these dyes to cotton required post-metallization of the unmetallized forms following their exhaustion on cotton. This alternative procedure gives dyeings with colors and properties comparable to those obtained from the premetallized copper complexes. The results of lightfastness testing indicate that metallization gives a significant improvement in the photostability of the unmetallized direct dyes, while there is little change in washfastness.*; *Please refer to dissertation for diagrams. |
