Konig’s salt

Konig s salt. Konig s salt (red), the unsaturated system of which is derived from a pyridine ring, is reduced by NaBH4 in aqueous ethanol at 0° to an enamine which on acid hydrolysis affords pentadienal (R. Grewe ). 

Ring fission of pyridinium ions with acceptor substituents, e.g. 7V-2,4-dinitrophenylpyridinium salts 221 (see p 280) leads, on treatment with secondary amines, to pentamethine cyanines 222 (Konig s salts). They condense with sodium cyclopentadienide to yield vinylogous aminofulvenes 223, which on cyclization produce azulene (azulene synthesis according to Ziegler and Hafner, see p 229 [73]) ... 

Pyridinium ions with acceptor substituents, for example, N-(2,4-dinitrophenyl) pyridinium salts 231 (cf p. 356), are converted to pentamethine cyanines 232 (Konig s salts) by ring-opening with secondary amines. Cyanines 232 condense with Na-cyclopentadienide to yield vinylogous aminofulvenes 233, which on cyclization afford azulene (Ziegler/Hafner azulene synthesis, cf p. 304) [137] ... 

Film thickness, um Film appearance Pendulum hardness (Konig), s Adhesion (crosshatch, DIN 53151) Erichsen impact, reverse, mm Conical mandrel bend (ASTM D522-60) Salt-spray resistance (ASTM B117-6U 10 d) 22-28 very good 195 Gt 0 >3 passed 9-9-2 22-28 good 170 Gt 0 >3 passed 85... 

Systematic investigations were carried out by Adler et al. [39-41] and Konig et al. [26] with various cultivation media. The voliunetric mass transfer coefficients ki,a were determined by a steady state method with distilled water, nutrient salt solution and various cultivation media in the presence and absence of antifoam agents. Volumetric mass transfer coefficients are strongly enhanced by increasing aeration rate. At low superficial gas velocities (< 2.5 cm s ) the... 

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