581-75-9Relevant articles and documents
Method of synthesizing, purifying and refining 2,6-naphthalene disulfonic acid
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Paragraph 0028; 0029; 0030; 0031, (2018/11/22)
The invention discloses a method of synthesizing, purifying and refining 2,6-naphthalene disulfonic acid. The method comprises the following steps of 1) sulfonation and solventing-out: heating refinednaphthalene and concentrated sulfuric acid for sulphonation to produce 2,6-naphthalene disulfonic acid and 2,7-naphthalene disulfonic acid, and performing solventing-out with water and filtering to obtain a 2,6-naphthalene disulfonic acid filter cake and a 2,7-naphthalene disulfonic acid mother liquor; 2) washing: by taking ammonia water with the mass percentage being 0.08-0.20 percent or a 0.15-0.28 percent ammonium sulfate aqueous solution as a washing reagent, washing the 2,6-naphthalene disulfonic acid filter cake to obtain a 1-grade 2,6-naphthalene disulfonic acid filter cake and a 1-grade refined filtrate, performing circulation washing on the 2,6-naphthalene disulfonic acid filter cake for 2-4 times at this way to obtain a 2,6-naphthalene disulfonic acid product with the purity larger than 99 percent; and 3) washing solution indiscriminate application: enabling the 1-grade refined filtrate to return for indiscriminate application to a solventing-out procedure in the step 1) and/or a washing procedure in the step 2), and enabling the residual refined filtrate to return for indiscriminate application to the washing procedure in the step 2). The method provided by the invention realizes the purposes of acquiring high-quality 2,6-naphthalene disulfonic acid with separation, refining and purification, increasing the yield of 2,7-naphthalene disulfonic acid and lowering wastewater discharge.
A ph switchable pseudorotaxane based on a metal cage and a bis-anionic thread
Clever, Guido H.,Shionoya, Mitsuhiko
supporting information; experimental part, p. 11792 - 11796 (2011/01/12)
Please let me in! A new kind of (pseudo)rotaxane is formed quantitatively when a bis-anionic thread is added to a molecular cage comprised of two positively charged metal complexes. The rotaxanation mechanism follows two alternative ways depending on the metal (Pd vs. Pt) and the stopper size of the guest (see figure).
Process for separation of naphthalenedisulfonic acids
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, (2008/06/13)
A process for separating 1,6-naphthalenedisulfonic acid, 2,6-naphthalenedisulfonic acid or 2,7-naphthalenedisulfonic acid selectively from reaction mixtures obtained by disulfonation of naphthalene under different reaction conditions is disclosed. For example, a particular disulfonation reaction of naphthalene is carried out which favors the formation of a particular isomer. This reaction mixture is diluted with water to adjust the sulfuric acid concentration to 35 to 90% by weight and the temperature is maintained at 0° to 80° C.; 1,6-naphthalene-disulfonic acid is selectively separated at high purity.