I''m trying to synthesize the diazonium salt from 4-aminothiophenol. Below is the experimental procedure:
Firstly, 0.005 mol of 4-aminothiophenol was dissolved in 10 ml distilled water with 1.1 ml concentrated HCl. (37%)
Secondly, 0.011 mol of NaNO2 was dissolved in 10 ml of distilled water.
After cooling in an icebath, NaNO2 was slowly added to the 4-aminothiophenol solution with stirring.
The question is, if the reaction yield is 100%, is the solution crystaline (transparent) or not? Is the diazonium salt completely dissolved in the solution in ion form?
In fact, everytime when I drop NaNO2 to the 4-aminothiophenol solution, there is always a suspension appears.
I would also expect the diazonium salt to dissolve in water, yes. However, I would also expect a thiol to react with a diazonium salt. You may need to mask the thiol if this is not your intention.
Dissolve 1 M amine in 2.5 M diluted hydrochloric acid (1: 1). Add 2.5 M sodium nitrite in an amount equivalent to the amine. Before the end of the diazotization, a sample is made for the presence of free HNO2 (iodine starch paper). Excess HNO2 acid is removed by urea. In the case of suspension, thorough mixing and slow addition of sodium nitrite .
Best regards.
Diazonium salt reacts with the thiol in ortho-position, making azo dye. After that, thiol group is oxidizing to disulfide from free nitrous acid. You must to convert thiol group to something else before diazotation.
I agree with the third answer, so you have to protect thiol group before diazotation
4-aminothiophenol melting point is around 25ºC. In cooling if you add sodium nitrite solution hazy moss will appear. after completion of addition try to increase temperature above 25ºC.
Hello, I am following the same procedure, Please I have many questions:
1. Does the concentration of HCL affects the solution performance? I saw some reviews focused only on the concentration (Mole/L), not on the solution volume.
2. Is the cooling stage for NaNO2 solution? or to the HCL 4-thiol mixture?
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