Reactive Dyes Bonding Mechanism
Reactive dyes are a class of dyes that form a permanent covalent bond directly with the fiber molecule. This chemical linkage is responsible for their excellent fastness properties.
Bond Formation
The reactive dye molecule contains a reactive group that chemically reacts with specific functional groups on the fiber polymer.
- In cellulosic fibers (like cotton, rayon), the reactive group typically reacts with the hydroxyl ($-OH$) groups.
- In protein fibers (like wool, silk), the reaction occurs with amino ($-NH2$) groups.
This reaction creates a strong covalent bond ($Fiber-Linker-Dye$), essentially making the dye part of the fiber structure.
Comparison with Other Bonds
- Ionic bonds involve electrostatic attraction and are characteristic of acid/basic dyes, but are less permanent than covalent bonds.
- Hydrogen bonds are weaker attractions and are not the primary mechanism for reactive dye fixation.
- Van der Waals forces are very weak interactions insufficient for permanent dyeing.
Therefore, the primary bond formed between reactive dyes and fibers is a covalent bond.
Important Questions from Chemical Bond and Molecular Structure
- Which reaction best supports the Law of Conservation of Mass?
- In Diborane, the B...H...B bonds are:
- Which type of chemical reaction involves the breakdown of a compound into two or more simpler substances?
Fire extinguishers emit which gas?
Which of the following statement(s) is/are CORRECT?
I. Carbon compounds linked by only single bond are called saturated compounds.
II. Carbon compounds having double or triple bonds are called unsaturated compounds.
III. Saturated carbon compounds are more reactive than unsaturated carbon compounds.
