[Ondex]

Hello!
Please help me with HEDP 60% neutralisation?
I need to obtaint tetrasodium etidronate, salt with high stability.
Ths!!

[AWK]

This is a quite simple neutralization reaction with NaOH. Balance this reaction and do stoichiometrical calculations. Someone will check your calculations.

[Ondex]

When i do by myself the neutralisation, next i am introduceing trilon b and after increase the ph with naoh to 13.5, the solution is not stable. In some days will see high cristal sediment.
But when i am using tetrasodium etidronate, neutralised in factory condition, by using the same quantity of trilon b and naoh, the sediment will not form.
What is a secred with hedp neutralisation? All the producers tell us that it is a trade secret!!
Thank you!

[AWK]

A wrong stoichiometry of neutralization of both reagents. That why I asked you to show calculations.

[Ondex]

C2H8O7P2 + 4 NaOH = C2H4Na4O7P2 + 4 H2O
For neutralisation of 20gr of HEDP (60%) i use 9.32 gr of NaOH.
https://www.webqc.org/balance.php?reaction=C2H8O7P2+%2B+NaOH+%3D+C2H4Na4O7P2+%2B+H2O
Something is wrong?

[AWK]

This part is correct. And what about neutralization of Trilon B.
Note, strongly alkaline solutions are unstable above pH about 9 since reaction with carbon dioxide from the air.

[Ondex]

I am.using neutralised Trilon b from Basf company.
How can i reduce the reaction with carbon dioxide? What i have to do in the process of neutralisation or what i have to add in sence to avoid the problem with sediment formation?

[AWK]

Storage of solutions under nitrogen - it will not hurt. Maybe the solutions were standing in the fridge? I `m not a prophet.

[Ondex]

When i use cublen 8514 gr, in same concentration as salt of neutralized acid (hedp), use the same amount of Trilon b and adjust the pH to the same index as in the formula in which I neutralize the hedp, i have never seen sediments ivent keeping final solution in cold place. Must cublen have something that does not permit the reaction between alcali and carbon dioxide? I observed if from this solution to exclude Trilon b, the sedimnetation will not form.

[AWK]

First of all - check these crystals and try to identify the chemical compound.
Repeat the experiment on the same small scale with particular accuracy and observe if the crystals appear again.
A lot of elements of experience can be checked only on the spot, and not at a distance.
By the way. Many, many years ago, a young chemist (later a Nobel Prize winner) taught students chemical synthesis. All students synthesized the same compound - pyruvic acid phenylhydrazone. All but one received the correct compound. This lucky man received a dark blue powder insoluble in any solvent. And the reason was the bottle used to store ethanol, which previously contained hydrochloric acid. And this powder turned out to be an indigo dye.
Maybe you also made a great discovery?

[Ondex]

Guys i think i did it.
I made some changes in the process of HEDP neutralisation and mixing of all ingredients, have already gone 2 days and no any cristals!!
I will try to oscillate the storage temperature to boost the crystallization processes, if it can still take place.
After 10 days I will be sure of the experiment.
Have a nice day!