Sciencemadness Discussion Board

how to sythesize ammonium citrate

ahill - 14-4-2020 at 00:43

I'm looking at growing some cordyceps militaris (mushrooms) - a few of the recipies for the media / substrate call for (amongst other things) diammonium hydrogen citrate.

I dont have that.

I've got citric acid, and ammonium hydroxide - I am tempted to add one to the other until the fizzing subsides - then attempt to desiccate - but thought it might be better to ask someone who might actually know.

So ..anyone know about preparing diammonium hydrogen citrate ?

Tsjerk - 14-4-2020 at 03:25

It won't fizz, unlike eg carbonates where CO2 evolves.

You have to add two mols of ammonia to one mole of citric acid.

What is the concentration and density of your ammonia? With those you can calculate how many milliliters you need. With the molecular weight of citric acid you can calculate how many grams you need.

Arcaeca - 14-4-2020 at 16:30

I feel it should be pointed out that because citric acid is a weak acid and ammonia is a weak base, they're not going to fully neutralize each other. Correct me if I'm wrong but I imagine once you try to evaporate the water off, the unreacted ammonia will also evaporate off leaving a mixture of ammonium citrate and unreacted citric acid.

ahill - 14-4-2020 at 23:44

Thanks Arcaeca.

..the plan now is just to aim for a neutral pH - I wont bother desiccating - the media needs water in it anyway..

Tsjerk - 15-4-2020 at 01:13

Ahh, desiccate... I read decant. Aiming for the correct amount and adding the rest of the components is a good idea. With media it is a good idea to aim for a volume of about 90% of the final, then set the pH and then top it off to 100%.
Good luck.