ISSN:
0930-7516
Keywords:
Chemistry
;
Industrial Chemistry and Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The chemical and photochemical properties of a photochromic water soluble triaryl methane dye sulphite, acid magenta monomethyl magenta sulphite, (AMMM · SO3)4-, have been examined, and the application of this photochromic system to the visualization of water flows is discussed. Addition of sulphite to an aqueous solution of the parent dye acid magenta monomethyl magenta, AMMM2-, (a methylated derivative of acid magenta, C.I. acid violet 19) leads to formation of the colourless sulphite complex, (AMMM · SO3)4-. Pulsed irradiation of a solution of this compound, with light of wavelength shorter than ≈ 340 nm, causes transient production of the parent dye, whose lifetime is influenced by pH, sulphite concentration, temperature and ionic strength. Longest useful lifetimes are of the order of a few seconds and a general equation is presented for the calculation of dye lifetimes for a variety of conditions. The complex formation constant for (AMMM · SO3)4- is 1.8 (± 0.2) × 105 M-1, while that for the weakly photochromic hydroxide (AMMM · OH)3- is 1.3 (± 0.3) × 106 M-1. The quantum yield of dye production at 308 nm is ≈ 0.5 - 1.0, and this is discussed along with the absorption spectra of AMMM2- and (AMMM · SO3)4- with respect to the penetration characteristics of a pulse of 308 nm laser radiation with an energy of a few millijoules. The action spectrum for dye production from (AMMM · SO3)4- suggests that there is a non-photochromic absorption band at about 350 nm, an assumption which is supported by the failure to detect efficient dye production when using 355 nm excitation from a Nd/YAG laser.
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ceat.270150410
