Phthalocyanine Compounds

Abstract

Phthalocyanines, a class of organic dyes, were discovered in 1907 and today are the main organic blue and green pigments in the industry. Phthalocyanines form complexes with a variety of chemical elements. The most important phthalocyanine, copper phthalocyanine, is produced worldwide. Synthesis usually starts with phthalodinitrile and metal or phthalic anhydride, urea, and metal salts as the starting materials. The reactions can be carried out in a solvent or at higher temperatures in a dry state. The chemical stability and physical properties have stimulated applications of phthalocyanines in fields like semiconductors, catalysts, lasers, and lubricants. However, 90% of the phthalocyanines are used as pigments for printing inks, paints, coatings, plastics, textile, and spin dyeing industries. Phthalocyanine dyes are predominantly used for dyeing of textiles, paper, and leather. The predominant phthalocyanine derivatives are formed with halogens (green pigments), sulfonic acids, and sulfonyl chlorides (dyes).

Nafion membranes with a sulfonated organic additive for the use in vanadium redox flow batteries

“…Although membranes including CuPCSA are very stable in acidic solutions, an ex situ test with 0.1 M VO 2 + in 2 M sulfuric acid revealed that the membranes lose the blue color within 10 min in contact with the strong oxidant. This is due to oxidation of the phthalocyanine system to phthalimide, which is a fast process used analytically for titrations . The relatively long timescale of 10 min is related to the slow diffusion of VO 2 + into the membrane.…”

“…In the current work, we add the blue dye into Nafion. Since VO 2 + rapidly degrades phthalocyanines into phthalimides, it is expected that the composite membranes rapidly turn into membranes containing well dispersed sulfonated phthalimide. On the one hand, phthalimide has an ion exchange capacity (IEC) of 4.4 mmol H + /g, and will increase the IEC of Nafion, which has an IEC of 0.9.…”