How to dissolve benzophenon 4 in water ?

My very lite blue Shower gel turns into coloursless in 2 or 3 months. UV index in our country is very high. To overcome this I tried to add benzophenon 4 . But when I tried to dissolve benzophenon 4 in water, it floats on water like milk powder.  Then I add Lactic acid in water to dissolve but failed.  
Then I add this undissolved benzophenon and water to my shower gel and stir. But most of them disappear but some white pieces were floating.  
My formulation is as follows :smile:
1. SLS                   3%
2. AOS                  3%
3. SLES (70%)     12%
4. CDEA                1%
5. CAPB    active   3%
6. EDTA                  .2%
7.L A to pH 6.5
8. Glycerine            2%
8. NaCl 
9. Perfume              .2%
10. PEG 400            .4%
11. Na benzoate    .4%
12. Colour   
13. Water to          100 %                


  • AzizAziz Member
    edited August 2020
    @letsalcido @Pharma
    Can you  help me regarding this.  
    I also tried with TEA but it was not dissolved. 
  • PharmaPharma Member, Pharmacist
    Use benzophenone 5 instead, it's the even better water soluble sodium salt of benzophenone 4 ;) .
    But honestly, BP 4 is very soluble in water. But it's also very acidic and will lower pH. Dissolve it in water, add an appropriate (equimolar) amount of a base such as TEA and that'll be it.
    What you observe might be other stuff falling out due to a lower pH (transiently and spatially localised around the dissolving BP 4 particles might suffice for such an effect)?
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