Reference

Photometric determination of nitrites in drinking and service water

Photometric determination of nitrites in drinking and service water. Kratochvil, Vaclav (Vyzk. Ustav Org. Synt., Pardubice-Rybitvi, Czech.). Vodni Hospod.: B, 34(11), 303-8 (Czech) 1984. CODEN: VHOBAF. ISSN: 0322-8231. DOCUMENT TYPE: Journal CA Section: 61 (Water) Section cross-reference(s): 79 The diazotization of 4-aminobenzenesulfonic acid (I) [121-57-3] and coupling of the resulting diazonium salt with either 8-phenylamino-1-naphthalenesulfonic acid (II) [82-76-8] or N-ethyl-1-naphthylamine (III) [118-44-5] was used in the photometric detn. of the NO2- concn. in water. The color intensity of the diazo dyes depended directly on the concn. of NO2-. For the diazo-I-II dye the max. light absorption was at 554 nm and it was stable for several hours. For the diazo-I-III dye the max. light absorption was at 537 nm and it was stable 24 h. The method was sensitive enough to det. 30.05 mg/L NO2- with acceptable accuracy.

Unsymmetrical trisazo dyes for liquid crystal materials

Unsymmetrical trisazo dyes for liquid crystal materials. Etzbach, Karl Heinz (BASF A.-G. , Fed. Rep. Ger.). Ger. Offen.Some commonly used reagents like 118-44-5 and 108-39-4 are used in this experiment. DE 3529988 A1 26 Feb 1987, 8 pp. (Germany) CODEN: GWXXBX. CLASS: ICM: C09B035-35. ICS: C09K019-24; D06P001-04. APPLICATION: DE 85-3529988 22 Aug 1985. DOCUMENT TYPE: Patent CA Section: 41 (Dyes, Organic Pigments, Fluorescent Brighteners, and Photographic Sensitizers) Section cross-reference(s): 37, 40, 74, 75 The title compds. I [R = Q, Q1; R8, R7 = C1-24 alkoxy, PhCH2O, Ph(CH2)2O, mono-C1-24-alkylamino, PhNMe, PhNEt, PhNH, bis(C1-24 alkyl)amino, ; R9 = H, Me; R1-R6 = H, Me, MeO, Cl; rings A and B can be condensed benzene ring systems], useful for coloring liq. crystal media, as well as for dyeing synthetic polymers or fibers, are prepd. 4-Amino-4'-nitroazobenzene was diazotized and coupled with m-cresol, the disazo intermediate reacted with n-C8H17Br, the product reduced with Na2S, the amino-contg. disazo intermediate diazotized and coupled with HQ (R8 = NHEt), forming I (R = Q, R8 = NHEt, R1-R5 = H, R6 = Me ortho to N:N, R7 = OC8H17-n) (II), having lmax (CH2Cl2) 532 nm. II had 2.1% soly. (room temp.) in ZLI 2452, and dichroic ratio 0.84. .