• Formulating

  EDTA

  Posted by Aanchal on November 18, 2019 at 8:02 pm

  Can Disodium EDTA be used instead of tetrasodium EDTA in dishwash formulation ? Intended pH is 8-9 .

  What should be the amount used?

  Aanchal replied 5 years ago 3 Members · 4 Replies

  • disodium-edta
  • tetrasodium
• 4 Replies

• 

  EVchem

  Member

  November 19, 2019 at 12:16 pm

  You  probably can, but I think the tetrasodium is supposed to be better for higher pH formulations (>7)

• 

  Aanchal

  Member

  November 19, 2019 at 1:18 pm

  Thanks @EVchem

  Yes, that was my concern too. I read about deriving tetrasodium EDTA from disodium EDTA by the use of alkaline medium like NaOH.

  It says, use the amount disodium EDTA equal to the amount of tetra sodium EDTA needed in the formula and dissolve it in NaOH solution. Each 5 parts of EDTA will need 1 part of NaOH to dissolve and convert.

  Is that the correct idea? 

• 

  Gunther

  Member

  November 20, 2019 at 12:48 am

  You can use it but you don’t want to.
  At that pH (8-9) most EDTA will probably become Tetrasodium itself anyhow.

  Disodium EDTA takes ages to dissolve, unlike Tetrasodium which readily dissolves.

• 

  Aanchal

  Member

  November 20, 2019 at 4:21 am

  Thanks @Gunther.

  Yes, at pH 8-9 the conversion and dissolution happens.

  So, last time I added EDTA (Disodium) in the NaOH solution first at pH8. Then proceeded to other steps.

  Got disodium EDTA mistakenly and have to consume it so.

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