chipster1234
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Sodium Hypochlorite 10% stability
Dear all
My first formula:
Water (51wt %),Sodium Hexametaphosphate Flakes (1.7wt%) KOH solid(8wt%), Sodium Hydroxide 48% (13wt%), Sodium Metasilicate Pentahydrate (0.5wt%), HEDP
Liagnd (0.5wt%) and Sodium Hypochlorite 10%(25wt%)
this was stable but it incurred higher cost. to reduce the cost, i tried the below:
Water (44wt %),Sodium Hexametaphosphate Flakes (1wt%) sodium Carbonate(5wt%), Sodium Hydroxide 48% (25wt%), Sodium Hypochlorite 10%(25wt%)
This yielded Huge precipitation and the solution turned brown.
I had to change this by removing the sodium carbonate
this had a marked improvement which reduces the amount of precipitation however the solution turned dark brown after a few days.
Water (49wt %),Sodium Hexametaphosphate Flakes (1wt%), Sodium Hydroxide 48% (25wt%), Sodium Hypochlorite
10%(25wt%)
May i know what is wrong? My customers will not accept the darkened coloured cleaners.
Can anybody please help me?
[Edited on 18-4-2012 by chipster1234]
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woelen
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The precipitation you had is due to the low solubility of sodium carbonate in concentrated sodium hydroxide solutions. The precipitate you had is
almost pure Na2CO3.
The brown color I cannot explain. All chemicals you mention are colorless in solution and I do not expect any reaction of these chemicals. The brown
color must be due to impurities in one of the chemicals or due to the bottle in which the cleaner is stored. It might be that the cleaner attacks the
material of the bottle.
What you left out is the ligand and the metasilicate. Maybe, these prevent attack of the bottle? This is the only thing which I can imagine.
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chipster1234
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Could it be because i took out the KOH which maye somehow help to improve the stability too?
Im not a chemist
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woelen
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I hardly expect that to be an issue. A solution of KOH in water is very similar to a solution of NaOH, I do not expect that to be a difference.
What you could try as a first start is taking your first formula and replacing the solid KOH by 15% of 48% solution of NaOH. I expect that this will
keep the properties almost the same. Then you remove the ligand from one sample and remove the silicate from another sample and try how well that
behaves. Always change one component at a time. The bottle also must be regarded as a component, you also can try changing that.
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