• Save
Bleaching cotton with hydrogen peroxide
Upcoming SlideShare
Loading in...5
×

Like this? Share it with your network

Share
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
862
On Slideshare
862
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
0
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Bleaching cotton with Hydrogen Peroxide
  • 2. Discovery
    • Discovered in 1818
    • Used for cotton bleaching 1866
    • High cost, Limited use
    • Industrial use as bleaching agent 1935
  • 3. Properties
    • Colourless liquid
    • Corrosive to skin
    • Stable under acid pH
    • Stabilized by phosphoric acid
    • Activated under alkaline pH
    • NaOH, Na2CO3, Trisodium phosphate alone or in combination may used as alkali for activation
    • Decomposition in presence of alkali alone is very rapid
    • Uneven bleaching
  • 4. Stabilizer
    • Compounds whioch control the rate of decomposition of H2O2 under alkaline conditions.
    • Sodium silicate is the most common and economical stabilizer
    • Other non silicate based stabilizers include
    • Metal chelating agents like EDTA
    • Decomposition products of protein
    • MgCO3 and CaCO3 present in hard water
    • Polyacrylates etc.
  • 5. Mechanism of H2O2 bleaching
    • Initial understanding
    • 2 H2O2  2H2O + O2
    • Not correct because beaching not achieved by atmospheric oxygen
    • Present understanding
    • In presence of alkali
    • H2O2 +OH  HO.