Preparation of 2-naphthol aniline dye - Aniline yellow- Azo dye

2-naphthol aniline is an azo dye which has this beautiful scarlet red color . It was being used in textile industry for dying clothes red.
If you directly want to see the video in it's synthesis
Follow this link to my video just recorded
https://youtu.be/gVh6Mn2IAB8
Or
Let's go directly into the procedure now

Chemicals required
Aniline 4.5ml
2-Naphthol 7.2g
Sodium nitrite 4g
conc HCl - 10ml
10% NaOH - 60ml
Glacial Acetic acid- 40ml

Procedure
Preparation of Crude dye
1. Take 4.5ml of aniline in a conical flask and add 10ml conc.HCl
2. Dilute with 20ml of distilled water
3. Create a saturated solution of NaNO2
4. In another beaker take 7.2g beta Naphthol and add 60ml of 10%NaOH to dissolve it
5.keep all the three solution for cooling to 0-5degrees in an ice bath
6.After cooling add Sodium Nitrite slowly into the Aniline HCl mixture -- make Benzene Diazonium Chloride

7. After cooling it. Add it to the cooled beta Naphthol solution.
8. Immediately dye seperate as scarlet red precipitate
9. Allow it stand for 30min and then filter the precipitate
10.dry the precipitate

Now to purify the crystals

Wash the precipitate with glacial acetic acid

Some amount of dye will dissolve in the acid on heating the solution which can then be filtered and recrystallised.

This is the link to the video I recorded on its synthesis. Do check it out and give your opinion there..
https://youtu.be/gVh6Mn2IAB8