2,7, Dichlorofluorescein

Hi

I would like to test Fajans's method for Cl- titration with silver nitrate

For this you have to use 2,7, Dichlorofluorescein as indicator

1) I have a lot of fluorescein sodium salt

Is it possible to chlorinated it ? how not sur-chlorinated it ?

It seems like 2,7 DCF is soluble in alcohol.
Tetrachlorofluorescein seems not soluble in alcohol

Is it possible to pass Cl2 gas in fluorescein in alcoholic solution and stop as it all dissolve ?



2) It's possible to synthetise 2,7 DCF by using same method use for Fluorescein by switching phtalic anhydride by the 3,6 Dichloro phtalic anhydride

how to synthetise 3,6 DAP ? (my organic chemistry is a little old)

thanks

Nobody for an anwser ?