Azo dyes are contain azo function group (N=N). The value of aromatic amines is determine by azo dye test.
It is bound to aromatic ring. azo dyes are synthetic class type dyes.
This dyes are windly used including, textile cloths materials and food.
It is mostly used in cellulose fibers as well as polyester fibers. it is easy to dissolve in water.
do you know how to determine the value of aromatic amines by azodye test.
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Azo dyes are soluble in water therefore, azo dyes are easily dissolve in water.
This dyes are chemical class of dyes. this dye are highly organic compound.
This dyes are contain azo function group (N=N). azo dye are properly bound to aromatic ring.
Its broken down with the help of high temperature. and Some important dyes are based on arylamines.
Azo dyes are windly used for the dyeing of cellulose materials as well as polyester materials.
This dyes are produced strong colour with good depth of shade on to the materials.
Different popular azo dyes are also be used in textile industries, for example Acid orange 7, (2- naphthol or orange-2).
Direct blue 15, and methyl yellow, acid red 13. this are the important class of azo dyes which is windly used in textile industry.
This dye gives good effect on cellulosic materials such as cotton.
This dyes have some important colouring Fuction property, this is the reason it gives good colour (shade) on materials.
But some azo dyes is harmful for skin but not all azo dyes. when this dyes are contect on skin then it may increase chances of skin cancer.
Reason azo dyes could be banned from skin contact. because azo dyes are highly soluble in water. and it is easy to absorb on to skin.
This is the reason it easy for the body to absorb during dyeing or during processing.
When azo dye are contect on skin then it may increase chances of damage of skin.
This dyes are easily accumulated and easy to absorb in the body.
Also increase the chances of exposure when wearing garments. so, some company are banned of azo dyes.
Azo Dyes Structure
Azo dye is a one type of organic compound. it contains function group such as (N=N).
This is also known as azo compound and this is also be used as a azo dyes. and used for treatment of textile materials and some foods.
It is also be used as a azo pigment. but it is insoluble in water. Making an Azo dyes from phenol, aniline and amines.
Preparation of an azo dyes
Preparation of azo dye from diazotization process.
Here, I m going to explain about preparation of an azo dyes with the help of diazotization process.
First of all aromatic amines (aniline) are transferred to diazonium component.
Then azo coupling reaction is carried out with phenol and naphthol. (reaction with coupling components process with phenol and naphthol). then it is given an azo dyes.
For preparation of an azo dye, I have provided valuable information.
so hold your seat and be with the end of guide. You could get valuable information out of it.
I have made this guide to help you out. let’s get started…
Aniline is directly transfer to diazonium component. and then coupling reaction is carried out with phenol or bet naphthol. it is given an red yellow azo dyes.
Preparation of an azo dyes (flow chart).
Aromatic Amines (aniline)
Cuppling reaction with cuppling component process with phenol or nepthole
Azo dye (red, yellow, orange)
These are the following steps for making an azo dyes. (Practically).
Azo C – Coupling reaction with phenol,
aniline, and beta – nepthol
1. In this reaction first phenol is directly react with benzene diazonium chloride and then make azo component, and it gives yellow product, this is called yellow azo dyes.
2. Aniline solution is react with same benzene diazonium chloride then it gives yellow product.
This product is called yellow azo color or yellow azo dyes. and azo dye test is produced aromatic amines (aniline).
Aniline is an aromatic amine and after reaction with aniline it gives yellowish azo dye.
3. In this reaction first beta nephthol (napthelene+alcohol = beta nephthol) is react with benzene diazonium chloride then make azo dyes component this is called red colour azo dyes.
Azo N – Coupling reaction with aniline
In this coupling reaction, aniline is directly reacted with benzene diazonium chloride and with maintain pH – > 7. then make an azo Component or azo dye.
What is an azo dye test?
Azo dye test is done for determine the value of amines. azo dyes test gives proper values of amines. In this process, different colourent, dye, pigments are used for colouration of apparel or accessories. this colourent are based on azo dyes and Anthraquinone dyes.
Azo dyes list
• Brown FK
• Congo red
• methyl red
• orange G
• orange B
• Sudan yellow 3G
• Black 3
Azo Dye Test for Aromatic Amines (method)
Aromatic primary amines can be determine by azo dye test.
In this case, aromatic amines for example: (aniline) is reacts with nitrous acid with HCl at 0-5°C to produce diazonium salt.
This solution is reacts with beta-napthol to produce red colour solution.
This red colour solution is known as red azo dye.
It is sparingly soluble in water.
Here, we are providing Process sequence of azo dye test methods.
Materials required for “azo dye test“
• test tube
• p glass
• glass rod
• gas burner
• bekar with ice
In case of azo dye test process, some important chemicals is required such as,…
• Aromatic amine (aniline)
• Beta Nepthole
Azo dye test is carried out with two steps. it is given below.
In case of azo dye test, first of all take aniline solutions in Test tube then add hcl. Heat for few seconds then cool, again add NaNO2 and mix properly then keep the solution in ice bath. it is given diazonium salt or diazonium component.
In second steps, again take beta-napthol solution in second test tube. then add sodium hydroxide (NaOH) then heat for few seconds then keep in the ice bath. then it is given beta-napthol solution.
Then add both solutions, for example.(Diazonium solution+ beta-napthol solution). Then it is given red colour solution. It is known as red azo dyes.
For better understanding we are providing process sequence of azo dye test.
First Take Aromatic amine (aniline C6H5NH2 solution)
Heat (10- 15 sec)
Again add NaNO2
Keep the test tube in ice cold bekar
Diazonium salt formed
Then again take second test tube
Take beta napthol in second test tube
Heat (for few seconds)
Keep the second test tube in ice bekar
Beta- Nepthol solution
Then add both solutions
diazonium salt + Beta – Nepthol solution
Azo dyes(Red colour) is formed
Here, I m going to explain about azo dye test reaction from phenol, aniline,beta nephthol.
Azo dye test for phenol
In this reaction, first phenol is directly react with benzene diazonium chloride.
Then it is given azo component or orange colour azo dyes product, it is known as orange azo dyes.
Azo dye test for aniline
In second reaction, aniline solution is react with same benzene diazonium chloride.
It is given yellow product and this product is called yellow colour azo dyes.
Azo dyes test is used for detarmine the value of aromatic amines.
Azo dye test is given aromatic amines. such as, aniline. aniline is an aromatic amine.
Aniline is easily diazotized on coupling reaction gives azo dyes.
This test is given yellow colour azo dyes but it turn red brown with contact of air or light.
Azo dye test for beta nepthol
In this azo dyes test reaction first beta nephthol (napthelene+alcohol = beta nephthol) is react with benzene diazonium chloride. and then it is given azo dyes component this is called red colour azo dyes.
Read more interesting articles with good guidelines……….
Azo dye test for phenol
azo dye is properly solublized in NaOH sodium hydroxide. after reaction it is given sodium phenoxide solution.
In this reaction, first phenol is react with NaOH then it is given sodium phenoxide. and then keep in ice bath.
Then add cooling benzene diazonium chloride solution then it is reaction between both component such as, Sodium phenoxide and benzene diazonium chloride. In other words;
“Sodium phenoxide+benzene diazonium chloride.”
then it is given azo component it is known as yellow – orange azo dye.
• Azo dye test for aniline
In this reaction, first of all some liquid of phenylalanine (aniline) is add in cooling solutions of benzene diazonium chloride.
and then mixed properly of both solutions. A yellow solid will produce. and yellow colour is formed.
This strong color is azo compound. this is used as a azo dyes or this is called azo dye.
• Azo dye test for beta nepthol
In this reaction, First of all
beta naphthalene is dissolved in NaOH (sodium hydroxide) and this solution will keep in ice bath for few time.
And then mixed properly with benzene diazonium chloride solution. and it gives Orange-red color. this product is also called red azo dyes.
Read more related term……..
• Azo dye test for aromatic amines?
In second reaction, (aromatic amine) aniline solution is react with same benzene diazonium chloride then it is given yellow product and this product is called yellow azo color or yellow azo dyes.
• How will you get azo dye from phenol?
First of all, in this reaction first phenol is react with NaOH then it gives sodium phenoxide. and then keep in ice bath and then add cooling benzene diazonium chloride solution. then it react between sodium phenoxide and benzene diazonium chloride. and then its make yellow – orange azo dyes.
• why azo dyes are banned?
azo dyes having “aminogroup” but some amines are careinogenic in nature. and some amines present in azo dyes but this amines are highly effected for skin. And because When dyes are contect on skin then this amines are easy to absorb or accumulated in the body and easy to absorb by the skin then thet cause skin cancer.
This is the reason some azo dyes are banned. this dyes are very harmful for skin if you are not use properly.
• what is azo dye test?
Azo dyes test is carried out for finding about aromatic amines. the main purpose of Azo dyes test is identifing about aromatic amines. Azo dyes test from phenol, aniline and amine is carried out for making an Azo dyes. Azo dyes is produce different colours such as, red, yellow and orange.
In this process diffrent colour, dye, pigment are used for colouration of apparel or accessories.
This is done with the help of azo or Anthraquinone.
• Azo dyes in textile?
Azo dyes are windly used in textile industries for the dyeing of cellulose materials as well as polyester materials. Azo dyes are produced strong colour with good depth of shade on to the materials. Different popular azo dyes are windly used in textile industries. Such as, Acid orange 7, direct blue 15, methyl yellow, acid red 13 and more.