Primuline

Two important browns, other than benzidine derivatives, are of azo chemical composition. Direct Brown 30 [6222-60-2] (82) (Cl 17630) is produced by coupling Primuline [30133-37-2] (Cl 49000) to N-phenylgamma acid under alkaline conditions. Direct Brown 44 [6252-62-6] (Cl 35005-35010) is produced by coupling two moles of sulfanilic acid to Bismark Brown [10114-58-6] (Basic Brown 1) (Cl 21000) forming a heterogeneous product with a significant component (83). 

Fluorescence measurement at 365 nm after derivatization with primulin... 

The thiazole ring system is found in many types of dye. Thiazole-containing sulphur dyes and primuline were considered in section 6.4-2. Quaternised dehydrothio-p-toluidine 6.133 is available as Cl Basic Yellow 1 (6.152). Other derivatives of this intermediate are used as direct dyes, such as Cl Direct Yellow 8 (4-58). The benzothiazole ring appears in various azo disperse dyes [14], quatemisation of which gives useful cationic dyes, an important example being Cl Basic Blue 41 (4.99). Another example containing a quaternised thiazole ring is Cl Basic Red 29 (4-102). 

Primuline is obtained by melting p-toluidine with sulfur and subsequently sulfonating the resulting product. It has the following chemical structure ... 

The dye component with the structure 125 is obtained through so-called primu-line fusion p-toluidine is heated with sulfur to 200 to 280°C. Subsequent distillation affords not only the primuline base ... 

The yellow crust is then finely ground and extracted with 95% alcohol. This dissolves the toluidine, thiotoluidine, and the dehydrothiotoluidine, leaving the insoluble primuline base (p. 389). The extract is evaporated to dryness and heated to 250°, which removes the toluidine and part of the thiotoluidine. The mixture is then sulphonated with 25% oleum and poured on to ice, filtered, and well washed with water until the washings give only a faint acid reaction. The toluidine and thiotoluidine sulphonic acids pass into solution. The residue is dissolved in 50 gms. of 20% ammonia solution and 800 c.cs. water, and heated to 80°, other 100 c.cs. of water being then added. The solution is filtered hot, if necessary, and the ammonium salt of dehydrothiotoluidine sulphonic acid separates out in the course of 2 days. Primuline can be obtained from the mother liquor by saturating with common salt at the boiling point. 

The mass, after cooling, is powdered and heated with 4 times its weight of fuming sulphuric acid (30% S03) to 70°—80° for a few minutes until a sample dissolves in caustic soda. The sulphonation mixture is poured into ice-water, and the sulphonic acid of the primuline base which is precipitated filtered and washed free of acid. 

The paste is stirred up with dilute ammonia until alkaline, filtered and washed with cold water. The residue is the ammonium salt of dehydro-thio-p-toluidinesulphonic acid (p. 326), and the filtrate contains the primuline. The filtrate is saturated with common salt, when the primuline separates out and is filtered and dried. 

Developed colouring matters are produced directly on the fibre by oxidation (e.g., aniline black) or by diazotisation and coupling (e.g., primuline,... 

Thioflavine S, diamine fast yellow B, F F, M, sulphine, primuline, chloramine, yellow, brilliant pure yellow, chlorazol fast yellow, th-azol yellow Clayton yellow, chlorophenine, dianil pure yellow H. naphthamine pure yellow G. diphenyl fast yellow, triazol fast yellow, Columbia yellow, oxydtand yellow, oxydiamine yellow, mimosa yellow, etc. 

Primuline developed with phenol or with resorcinol, cotton yellow G and R. oriol - yellow, dianil yellow, etc, " ... 

Chlorophenine, chloramine yellow, diamine fast yellow B, F F, and C, Clayton -yellow, thiazol yellow, thioflavine S, etc. Primuline developed with hypochlorite. 

Research by Zerweck et al. [2] suggests that many bake dyes contain thiazole rings. It was already known that dehydrothio-p-toluidine, which can be made by sulfur baking of />-toluidinc, and primulin bases, which are formed at higher temperatures, are both thiazole derivatives. 

Acetoacetic acid arylides and pyrazolone derivatives are the coupling components mainly used. Naphtbolsulfonic acids are of only minor importance here. Dehydrothio- p-toluidine sulfonic acid (2) and the sulfonated primulin base are also used as diazo components for certain orange disazo direct dyes. 

Coupling the diazotized monosulfonic acid of the primulin base to acetoacetic acid anilide produces the clear, greenish yellow C. I. Direct Yellow 22, 13925 [.10190-69-9] (21). 

Substantive yellow monoazo dyes with very good light fastness are also obtained by oxidation of dehydrothio-p-toluidine and its derivatives. Oxidation of the sodium salt of the monosulfonic acid of the primulin base in the alkaline pH range with sodium hypochlorite results, for example, in C. I. Direct Yellow29, 19556 [6537-66-2] (22). 

Erythrosine Extra Fuchsin S Guinea Green B Hessian Purple NR Columbian Black Naphthol Yellow S Nyanza Black Orange II Patent Blue A Picric Acid Ponceau 4GB Primuline Resorcin Yellow Rose Indulin 2G Acid Violet 5BN Acid Violet 6B Salm Red Tartrazin... 

Clayton yellow paper (thiazole paper) is paper impregnated with the dye formed by coupling diazotized primuline sulfonic acid with primuline sulfonic acid. The color change occurs at pH 11-12. If this paper is not available, a little less than the estimated amount of alkali should be used. The mixture is warmed to 85 and a small test portion is removed and warmed with more alkali. If any appreciable amount of the insoluble matter dissolves, more alkali is needed. 

Iron fusion kettle with copper dl bath for use in primuline,... 

As already mentioned, the basic operations of dye chemistry utiUze simple chemical reactions. An intermediate can frequently be prepared in several entirely different ways and, in these cases, careful calculations must be made to determine which procediure is most advantageous. The least expensive process is often not necessarily the best when other factors are taken into account. For example, the question of apparatus may enter, and calculations may show that it is uneconomical to purchase an expensive apparatus for the process if a small quantity of the material is to be produced. Furthermore, consideration must be given to the usability of the side products formed. These often cannot be used at all (e.g., primuline), but may be valuable or even indispensable in another process (e.g, chromium sulfate in the production of anthraquinone). 

Naphthylamine is usually vacuum distilled in the plant. The distillation must be done very carefully, since the compound decomposes easily. For sulfonation reactions, if the free base is not isolated, the thoroughly dried sulfate, mixed with 1 per cent soda (see also primuline), is added to sulfuric acid or oleum. 

Method 2. The finely pulverized melt is extracted with alcohol of at least 90 per cent strength. The toluidine, thiotoluidine, and dehydrothiotoluidine go into solution leaving a pure primuline base behind. The alcoholic extract is evaporated to dryness, and the toluidine and part of the thiotoluidine are driven off by heating to 2M°C. Sulfonation of the primuline base is done with 25 per cent oleum. 

Method 3. Sulfonation is carried out exactly as in the first method. The washed sulfonic acid is dissolved at 80°C. in 20 parts of water and the required amount of sodium hydroxide sufficient salt is added to make an 8 per cent salt solution, and the mixture is filtered at 75°. The primuline remains behind, while the dehydrothiotoluidine sta in solution in the form of its soluble sodium sulfonate and is subsequently salted out. 

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