Discussion in 'B&W: Film, Paper, Chemistry' started by maxbloom, Jan 13, 2008.
Can anyone comment on how long this will keep in solution? Thanks.
in my experience, Benzotriazole keeps pretty well in slightly alkaline solutions. Take a look at this photo.net thread:
My 1% solution in tap water seems to work and it's been about a year. My tap water is slightly alkaline (about 7.6 ph) so this might be a factor.
Any recommendations on an appropriate alkaline additive to my neutral pH water?
What about dry BZT shelf life?
from the thread link I posted earlier:
Benzotriazole can also decompose slowly in alkaline solution. A neutral organic solvent is best for long shelf life.
Ethyl, Propyl, or Methyl alcohol are best.
Sodium sulphite is alkaline. A small amount will do, probably in the range of a 1% solution (10g per litre), which should give a pH in the neighborhood of 7.5 or so. A 5% solution will give a pH of 8.0 or so. This could have some impact on photochemical reaction depending on how it is used. However, you'll likely be using a small amount benzotriazole so it may not matter. Isopropyl alcohol would be a good liquid to dissolve in as well.
I'll give isopropanol a try. AFAIK it's generally the least reactive of the three.
Hmmm...all the alcohols I know are quite WET.
I think dry BZT lasts a very long time. I've had no trouble using stuff that is years old.
Benzotriazole is used in boilers as a corrosion inhibitor. Since it lasts well in those conditions it should last quite well in a bottle of solution in the home. It dissolves better in mild alkaline solutons. Sodium sulphite is alkaline enough to improve its solubility. This what the old Orthazite solution was.
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