| Benzidine used to be one of the most important dye intermediates. It was banned from use since 1970s because of its strong mutagenic activities. Recent years, the formerly studied substitute of benzidine, 3,3'-dimethylbenzidine and 3,3'-dimethoxybenzidine were also banned since 1995. So, it is very important to find another substitutes.In this paper, the mutagencity of the diamines is removed by incorporating huge alkoxyl substituents ortho to the amine groups, and these nonmutagenic diamines are used in the synthesis of nonmutagenic dyes. The influences of the dyes structure to substantivity are also studied.Firstly, the nonmutagenic 3,3'-dialkoxybenzidine are synthesized in 3 steps from o-nitrochlorobenzene. namely alkaline hydrolysis, nucleophilic substitute reaction and benzidine arrangement. Totally three diamines are synthesized, and the yield of 3,3'-dipropoxybenzidine, 3,3'-dibutoxybenzidine and 3,3'-di~p-hydroxy-ethoxybenzidine are 53%, 58% and 51% based on the corresponding nitro compounds, respectively. The process for the synthesis of o-nitrobenzenyl-|3-hydroxyethyl ether is optimized by orthogonal experiment, and the yield was raised from 58% to 78%. The structure of all these compounds is determined by IR, MS and NMR method.Then three nonmutagenic derivatives of meta-phenylenediamine, a potential mutagenic diamine, is synthesized in 2 steps from 2,4-dinitrochlorobenzene, namely nucleophilic substitute reaction and catalytic hydrogenation. The yield of 2, 4-diamino-l-n-propoxybenzene, 2, 4-diamino-l-n-butoxybenzene and 2, 4-diamino-P-hydroxyethoxybenzene based on l-chloro-2,4-dinitrobenzene are 91.0%, 90.8% and 74.1% respectively. The structures of them are determined by MS spectrum.Using above mentioned three 3,3'-dialkoxybenzidine as diazo components, and three 2.4-diamino-l-alkoxylbenzene as coupling component, totally 12 new greenish black trisazo direct dyes are synthesized which are the analogues of C.I.direct black38. At the same time, three other black trisazo direct dyes sunthesized from three bridged diamines, 4,4'-diaminobenzanilide, N,N'-di-(4-aminophenyl)-urea and 4,4'-diamino- 2,2'-stilbenzene disulfonic acid (DSD acid), are synthesized. All of these dyes are nonmutagenic dyes and hopeful substitutes for C.I. direct black 38.After the synthesis of dyes, the purification process are performed on a silicagel chromatography column and obtained the dye with 85% purity. The structure of the dyes are determined by MS spectrum, so does one major by-product. The formation mechanism of this by-product is also discussed.The applied performances of all these fifteen trisazo black dyes are measured and compared with C.I. direct black 38. The experiment shows that the light fastness and washing fastness of the dyes using 3,3'-alkoxybenzidine as diazo components is similar with C.I. direct black 38, while the exhaustion degree is a little lower than it. Such dyes' color is greenish black and very similar with C.I. direct black 38, among which the dyes derived from 3,3'-di-(3-hydroxy-ethoxybenzidine are especially well in that its exhaustion degree is only 7.1% lower than C.I. direct black 38. The dyes derived from 4,4'-diaminobenzanilide and N,N'-di-(4-aminophenyl)-urea are reddish black and not as good as C.I. direct black 38 and the' dyes derived from 3,3'-dialkoxybenzene. The exhaustion degree of the dye synthesized from DSD acid is only 29.1% and not suitable as substitute of C.I. direct black 38.Finally, the influences of the dyes structure to substantivity are studied by molecular mechanics program PCMODEL. The dyes used in the experiment are symmetric diazo dyes using benzidine, three 3,3'-dialkoxybenzidine, 4,4'-diamino-benzanilide, N,N'-di-(4-aminophenyl)-urea, DSD acid and 4,4'-diamino-benzenesulfonamide as dizao components and H-acid as coupling component. The subtantivity sequence of these eight dyes derived from the eight diamines is as follows: benzidine> 3,3'-di-p-hydroxyethoxybenzidine> N,N'-di-(4-aminophenyl)-urea> 3,3'-diprop...
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