How would one prepare magnesium citrate from magnesium chloride and citric acid? Will it work if I just heat a mixture of magnesium chloride and citric acid in water? I'd expect HCl to vaporize off.
Does anyone have experience with this reaction? Yield, purity, concentrations, byproducts, ... So if I just try to make magnesium citrate directly by mixing the chloride and citric acid, will that work – or is the citrate going to degrade/decompose into organic byproducts?
I have a large amount of high purity magnesium chloride on hand which is slowly deliquescing anyway. I'd like to convert it into magnesium citrate (molar ratio of magnesium to citrate isn't hugely important, aim between 1 and 1.5) which is easier to store – and I need it anyways (need magnesium solution chelated with citrate and bitartrate).
I figure I could buy citric acid food grade, which is cheap enough, to make magnesium citrate. Objective is to have a high yield, low energy usage if possible (not having to boil off loads and loads of water, not having many steps), and no byproducts / few and easy purification steps necessary (a high grade end result consisting of only citrate and magnesium).
Economic feasibility (answer)
Magnesium chloride hexahydrate costs about 2.5 €/mol and sodium carbonate 1.1 €/mol. The product, magnesium carbonate is worth about 2.6 €/mol. So converting to carbonate results in a loss.
Citric acid monohydrate costs about 2.6 €/mol. The product, magnesium citrate is worth about 12.3 €/mol. So this step is profitable (gain 12.3 at a cost of 2.6+2.6).
Converting magnesium chloride into its citrate directly (if it were at all possible) would be profitable (gain 12.3 at a cost of 2.6+2.5).