Please tell me the structure and properties of 2 dyestuffs: moderacid black MD & moderacid sky blue?

The first thing you have to do is find the generic names of your dyes. This takes just a little web searching. Moderacid Sky Blue RB is Colour Index Acid Blue 62. Unfortunately, Moderacid Black MD is a mixture of two or more dyes, so the structure and properties cannot be determined without more information from the manufacturer.

Once you have your Colour Index names, you can search for more information much more easily. Search with "Acid Blue 62", using the quotes. You can find that this dye is a member of the class of dyes referred to as leveling acid dyes. This class of acid dyes is relatively poorly washfast, so items dyed with it should be hand-washed in cold water only, or, preferably, dry cleaned only. However, due to the same properties it is easy to get a single solid level color when dyeing with this dye.

Even though you don't, at this point, know exactly what dyes are found in your Moderacid Black MD dye mixture, you can bet that they are leveling acid dyes, since they have been labeled with the same trade name as the blue dye that you know is one.

Colour Index Acid Blue 62 is sold to artists under the name "623 Brilliant Blue" by Jacquard Products. They include some information about its properties on their web site. More figures are available on the lightfastness page. Its washfastness is rated as being rather poor in cool water (40°C), at only 2 to 3 on a scale of 1 to 5. Its lightfastness is 4 or 5 on a scale of 1 to 8.

For more information still, try to find the US CAS number. For acid blue 62, a quick internet search rapidly turns up CAS# 4368-56-3, and the Colour Index Number is CI 62045. (Put the number "4368-56-3" in quotes when you search with it, so that the search engine does not break the number at the dashes.) Acid Blue 62's molecular formula turns out to be C₂₀H₁₉N₂Na₂O₅S. Its full chemical name is sodium 1-amino-4-(cyclohexylamino)- 9,10-dihydro- 9,10-dioxoanthracene- 2-sulphonate. In addition to its usage in the textile industry, it is also used in hair dyeing.

You can use the name to draw the chemical structure, or you can do more web searching using the numbers above to look for someone else's drawing of it.

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[This answer was originally posted by me on Yahoo Answers on March 27, 2008.]