The Schlenk equilibrium depends on several factors, e.g. Temperature, Solvent, concentration, etc.. Addition of MgX2 should move the equilibrium to the mono-Grignard.

For mor einformation take alook at the following book

https://epdf.tips/handbook-of-grignard-reagents-chemical-industries.html

Hi Rajkoti,

To avoid dimer formation use more solvent and also use cool bath to control temperature and keep it at a range just the reaction go. Good luck

Dear Rajkoti Katkuri, I am phasing similar problem. what was the RX that you used? Also, how what method did you use to determine how much active R-Mg-X you have?

What reaction conditions do you use? Because this looks like there may be several things wrong.

1) Atmosphere. You need to keep argon or nitrogen atmosphere tight to avoid reagent oxidation.

2) Heat. If you have a highly reactive radical forming, you may want to start cooling reaction on a water or water/ice bath right after it initiates.

3) Too much iodine. That's a rare one, but some people get overzealous and iodides are way too reactive sometimes. If your magnesium is fresh, iodine may not be needed at all.

4) Concentration. I've done this before- if you don't scale the amount of solvent (THF) in reaction appropriately it may get too exothermic and reagent may degrade in process.

Hope that helps.

we have characterized the dimeric product