Aniline sulfonation

As a diazonium component, aniline sulfonic acid may occasionally be replaced by 2-aminonaphthalene-l-sulfonic acid or by aniline. 

Aromatic aminosulfonic acids are synthesized by a sequence of important industrial processes, including sulfonation of benzene. This is followed, wherever necessary, by chlorination, nitration, and reduction, or by aniline sulfonation, possibly involving subsequent baking [7,8]. 

Pigment synthesis follows the typical route to azo pigment lakes the aniline derivative or the aniline sulfonic acid is diazotized with sodium nitrite in an acidic medium (hydrochloric acid), followed by coupling on the Naphthol AS derivative, which is initially dissolved in an alkaline solution and then precipitated by adding inorganic or acetic acid. If a Naphthol AS sulfonic acid is used as a coupling component, it must be neutralized with alkali for dissolution and coupled directly. 

The pigments are synthesized by diazotizing the aniline derivative or the aniline sulfonic acid with sodium nitrite in hydrochloric acid and subsequently coupling onto the naphthalene sulfonic acid derivative, which is previously dissolved by neutralizing with a sodium hydroxide solution, producing the corresponding azo dye solution. 

The threshold limit for aromatic aminosulfonic acids, expressed as aniline sulfonic acid, must be below 500 ppm. 

Recent work reports the incorporation of aniline sulfonic acid derivatives, o- and m-aminobenzenesulfonic denoted as 1 and 11, respectively, 3-amino-4-methoxybenzenesulfonic (HI), 3-aniline-1-propane sulfonic acid (IV), and... 

Fig. 23 ESR spectra of Cu2Cr/aniline sulfonic acid derivatives after a thermal treatment at 200 °C for 4h in air recorded at 105 K with a sweep width of a 6500 G b 150 G. H(I) o-aminobenzenesulfonic acid H(I) m-aminobenzenesulfonic acid H(III) ...

N 15.15%. Three isomers are known. They are all expl and can be prepd by diazotizing the corresponding aniline sulfonic acid Ortho or 2-DU azo-, col cryst solid, expl weakly on heating si sol in w decomp in hot w or hot ale Meta or 3 -Diazo-, col prisms(from w), expl even by touching and on heating decomp in w at 60° or in hot ale and Para or 4-Diazo-, col ndls(from w) expl in dry state by heating(fl p 150°, Ref 2), on impact or friction sol in hot w or dil alkalies decomp in hot ale... 

Whereas p -naphthylaminesulfonic acids always couple at the adjacent a position, in a-naphthylaminesulfonic acids, the coupling location is influenced by the position of the sulfonic acid group 1,6-, 1,7-, and 1,8-naphthylaminesulfonic acids couple at the 4-position 1,5-naphthylaminesulfonic acid (Laurent acid) only couples with very strong couplers (e g., 2,4-dinitroaniline), mainly at the 4-position. With diazotized aniline, chloroaniline, or diazotized aniline sulfonic acids the 2-aminoazo dyes are obtained, but with diazotized nitroaniline, mixtures of the 2-and 4-coupling products form (Scheme 2.1). 

Another sequence of reactions starting with DAS is needed for weakly basic amines, such as aniline sulfonic acids, and also for alcohols. These are initially treated with cyanuric chloride, then with DAS in an aqueous medium at 40-50 °C. In this way the number of side reactions is substantially reduced. 

In a 3-I. round-bottom flask fitted with a reflux condenser are placed 218 g. (1 mole) of coarsely powdered technical o-nitro-aniline-/>-sulfonic acid, and a hot mixture of 775 cc. of concentrated sulfuric acid (sp. gr. 1.84) and 950 cc. of water (Note 1). Heat is applied and the mixture is refluxed gently for. an hour after solution is practically complete (total about three hours). The resulting dark solution is allowed to cool and is poured slowly into 12 1. of cold water in a crock (Note 2). 

Yang et al. [53] prepared a novel series of metal-containing poly(imide)s. Polymers of pyromellitic dianhydride with the zinc, strontium, lead, calcium and nickel salts of p-aniline sulfonic acid, were prepared and examined by C CPMAS NMR. There was little difference in the chemical shifts of the dianhydride carbons, compared with the chemical shifts of the poly(imide) with diaminodiphenyl methane. 

E.M. Moujahid, M. Dubois, J.-P. Besse, and F. Leroux, Role of atmospheric oxygen for the polymerization of interleaved aniline sulfonic acid in LDH, Chem. Mater., 14, 3799-3807 (2002). 

Route 1 is principally the diffusion of the monomers within the LDH and subsequent polymerization of e monomers inside the host material. These trials were carried out for LDH previously modified with aniline sulfonic acid (ANIS) and sodium dodecylbenzenesulfonate (DBS) by regeneration method. The chosen polymerization method was emulsion polymerization of aniline since it is one of the most promising methods to improve the processibility of PANI [35]. The polymerization method was performed from the work of Liu [36], which was done by using oleic acid as dopant and surfactant. Organo-modified LDH was dispersed in water and followed by addition of monomer, aniline and dopant, acetic acid (AA). It was found out that in all cases, conductivity values were rather low with this approach. 

Y. Sahin, K. Pekmez, A. Yildiz, Electrochemical preparation of soluble sul-fonated polymers and aniline copolymers of aniline sulfonic acids in dimethyl-sulfoxide, Journal of Applied Polymer Science 2003, 90, 2163. 

Example 1 Polyaniline-Sulfomc Acid - Synthesis of Aniline/Sulfonated Aniline Copolymer... 

N-Methyl-anilin sulfons uie-(3) 14, 690. N-Methyl-amlm sulfoDS UTe-(4) 14, 699,... 

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