Hydroquinone - help to dissolve

[AlexRT]

Hi,

I have tried to mix some lith developers and met with a small issue, which i could not resolve yet.
I need to dissolve 135g of Hydroquinone in 500-700 ml water and I could not do it. I am able to dissolve this amount of Hydroquinone in 1L water.

How I do it: I take water about 50-60C and try by manual to mix here Hydroquinone. when I take about 500-600ml of water i can not completely dissolve it and need to add some water, try again - add again some water and finally the Hydroquinon will be dissolve when water about 1 L.

I do not have any mix devices for chemical, only a kitchen mixer.

 

[Andrew O'Neill]

Goodness me that is a lot of Hydroquinone in such a small amount of water. Even in 52C water, it's still not going in?

 

[AlexRT]

this is only one part of 2 part developer, this developer I use for paper: 1:4:10-30(water), total amount of developer - about 6 L

 

[dE fENDER]

As I said to you at rangefinder, it cannot be dissolved at normal temperature in such quantities. It's solubility is about 6g/100ml at 15 C. You need to heat it up to 50 C before mixing.

 

[AgX]

But the OP stated to have heated the water up to 50-60°C before adding the Hydroquinone.

 

[BradS]

Are you certain that the recipe calls for 135g ? That seems like an awful lot of Hydroquinone! Maybe, it is really supposed to be 13.5 g ?

 

[AlexRT]

It's solubility is about 6g/100ml at 15 C. You need to heat it up to 50 C before mixing.

Nice to hear you, I do same - water is about 55-60 C, but all hydroquinone could not be dissolved, at least I can not do, I need to add the fresh water to existing volume for continue of dissolving. The total volume, where all hydroquinone dissolved is about 900 ml.
Possibly, I need to use more intensive and prolonged stirring or another way to mix do big amount

 

[AlexRT]

Are you certain that the recipe calls for 135g ? That seems like an awful lot of Hydroquinone! Maybe, it is really supposed to be 13.5 g ?

Yep - 135 g, lith is working, but I try to follow of the receipt: mix 135g hidroquinone in 700 ml water

 

[dE fENDER]

Nice to hear you, I do same - water is about 55-60 C, but all hydroquinone could not be dissolved, at least I can not do, I need to add the fresh water to existing volume for continue of dissolving. The total volume, where all hydroquinone dissolved is about 900 ml.
Possibly, I need to use more intensive and prolonged stirring or another way to mix do big amount

Add hq to water in a bottle and put the closed bottle under running hot water, with some shaking periodically. It it doesn't dissolve, the temperature is not enough

 

[AlexRT]

Add hq to water in a bottle and put the closed bottle under running hot water, with some shaking periodically. It it doesn't dissolve, the temperature is not enough

thanks de Fender, I ll try this way today - I have suspected that water is not enough hot for dissolving so big amount of HQ

 

[dE fENDER]

thanks de Fender, I ll try this way today - I have suspected that water is not enough hot for dissolving so big amount of HQ

Did you add Ethylene glycol or DEG required by the recipe?

 

[AlexRT]

I added the Diethylenglycol. Lith is working, I just interested how to mix so much HQ in 500-700 ml water, will try to use hot water and more intensive stirring

 

[dE fENDER]

You cannot dissolve more hq in water beyond it's natural solubility without additional solvent. Look an the HQ solubility tables, little one is in ruwiki.