Home >
Community >
How do I prevent oxygen interfering when I prepare a FeCl2 solution from anhydrous FeCl2 powder?
Upvote
VOTE
Downvote
+ Minerals
+ Chemistry
+ Redox
Posted by
Laszlo Petruska
How do I prevent oxygen interfering when I prepare a FeCl2 solution from anhydrous FeCl2 powder?
My variation on the suggested synthesis is not the direct addition of, say, the metal iron (has already been suggested), but instead the partitioned introduction into the reaction chamber of an oxygen scavenger.
For example in one possible embodiment, in place of the direct intervention of Fe in the reactive solution mix, just place a small amount of freshly prepared fine powdered magnesium metal in the chamber, but not in direct solution contact.
My logic is that magnesium metal acting as an oxygen scavenger will anodically corrode (to MgO) with oxygen, thus mitigating the further possible action of oxygen on ferrous ions.
The procedure is then mixing of the FeCl2 reagent directly with NaOH, MgCl2 and Na2S, in the presence of a potential separated side surface reaction between Mg and any present oxygen.
If this fails, try a layer of Mg powder on the reactive mix. However, as in the case of suggested employment of Fe, the resulting chemistry may or may not favor the targeted formation of the mineral tochilinite ($\ce{6Fe_{0.9}S⋅5[Mg,Fe](OH)2}$).
My variation on the suggested synthesis is not the direct addition of, say, the metal iron (has already been suggested), but instead the partitioned introduction into the reaction chamber of an oxygen scavenger.
For example in one possible embodiment, in place of the direct intervention of Fe in the reactive solution mix, just place a small amount of freshly prepared fine powdered magnesium metal in the chamber, but not in direct solution contact.
My logic is that magnesium metal acting as an oxygen scavenger will anodically corrode (to MgO) with oxygen, thus mitigating the further possible action of oxygen on ferrous ions.
The procedure is then mixing of the FeCl2 reagent directly with NaOH, MgCl2 and Na2S, in the presence of a potential separated side surface reaction between Mg and any present oxygen.
If this fails, try a layer of Mg powder on the reactive mix. However, as in the case of suggested employment of Fe, the resulting chemistry may or may not favor the targeted formation of the mineral tochilinite ($\ce{6Fe_{0.9}S⋅5[Mg,Fe](OH)2}$).
See if your group or an other (e.g., organic / organic catalysis) has a Schlenk line. With some training, this allows you to reduce the interference of oxygen greatly, because you may evacuate your reaction flasks and to replace the air by an inert gas such as nitrogen or argon. Nitrogen is relatively cheap because it equally is used for welding (as gas) or for cooling (think e.g., NMR spectrometers). Argon gas, on the other hand has the advantage of a density greater than the one of air, thus you may cover and protect your substance under a blanket of argon.
Then, search for Schlenk flasks. You identify these quickly for their connector to said Schlenk line. Besside round bottom flasks and tubes (a gallery, a second one), there equally are Schlenk flasks to perform a pressure filtration while working under argon enclosing a filter plate (example).
Then, degas your solvent. In HPLC, bottled solvents for example are placed in the basket of the ultrasound bath while purging them with a steady, slow flow of argon to remove dissolved oxygen. Do this for your deionized water.
Weigh in $\ce{FeCl2}$ in your dry Schlenk flask, and add the deionized water prepared under the inert gas.
See if your group or an other (e.g., organic / organic catalysis) has a Schlenk line. With some training, this allows you to reduce the interference of oxygen greatly, because you may evacuate your reaction flasks and to replace the air by an inert gas such as nitrogen or argon. Nitrogen is relatively cheap because it equally is used for welding (as gas) or for cooling (think e.g., NMR spectrometers). Argon gas, on the other hand has the advantage of a density greater than the one of air, thus you may cover and protect your substance under a blanket of argon.
Then, search for Schlenk flasks. You identify these quickly for their connector to said Schlenk line. Besside round bottom flasks and tubes (a gallery, a second one), there equally are Schlenk flasks to perform a pressure filtration while working under argon enclosing a filter plate (example).
Then, degas your solvent. In HPLC, bottled solvents for example are placed in the basket of the ultrasound bath while purging them with a steady, slow flow of argon to remove dissolved oxygen. Do this for your deionized water.
Weigh in $\ce{FeCl2}$ in your dry Schlenk flask, and add the deionized water prepared under the inert gas.
My variation on the suggested synthesis is not the direct addition of, say, the metal iron (has already been suggested), but instead the partitioned introduction into the reaction chamber of an oxygen scavenger.
For example in one possible embodiment, in place of the direct intervention of Fe in the reactive solution mix, just place a small amount of freshly prepared fine powdered magnesium metal in the chamber, but not in direct solution contact.
My logic is that magnesium metal acting as an oxygen scavenger will anodically corrode (to MgO) with oxygen, thus mitigating the further possible action of oxygen on ferrous ions.
The procedure is then mixing of the FeCl2 reagent directly with NaOH, MgCl2 and Na2S, in the presence of a potential separated side surface reaction between Mg and any present oxygen.
If this fails, try a layer of Mg powder on the reactive mix. However, as in the case of suggested employment of Fe, the resulting chemistry may or may not favor the targeted formation of the mineral tochilinite ($\ce{6Fe_{0.9}S⋅5[Mg,Fe](OH)2}$).
My variation on the suggested synthesis is not the direct addition of, say, the metal iron (has already been suggested), but instead the partitioned introduction into the reaction chamber of an oxygen scavenger.
For example in one possible embodiment, in place of the direct intervention of Fe in the reactive solution mix, just place a small amount of freshly prepared fine powdered magnesium metal in the chamber, but not in direct solution contact.
My logic is that magnesium metal acting as an oxygen scavenger will anodically corrode (to MgO) with oxygen, thus mitigating the further possible action of oxygen on ferrous ions.
The procedure is then mixing of the FeCl2 reagent directly with NaOH, MgCl2 and Na2S, in the presence of a potential separated side surface reaction between Mg and any present oxygen.
If this fails, try a layer of Mg powder on the reactive mix. However, as in the case of suggested employment of Fe, the resulting chemistry may or may not favor the targeted formation of the mineral tochilinite ($\ce{6Fe_{0.9}S⋅5[Mg,Fe](OH)2}$).
More
VOTE
See if your group or an other (e.g., organic / organic catalysis) has a Schlenk line. With some training, this allows you to reduce the interference of oxygen greatly, because you may evacuate your reaction flasks and to replace the air by an inert gas such as nitrogen or argon. Nitrogen is relatively cheap because it equally is used for welding (as gas) or for cooling (think e.g., NMR spectrometers). Argon gas, on the other hand has the advantage of a density greater than the one of air, thus you may cover and protect your substance under a blanket of argon.
Then, search for Schlenk flasks. You identify these quickly for their connector to said Schlenk line. Besside round bottom flasks and tubes (a gallery, a second one), there equally are Schlenk flasks to perform a pressure filtration while working under argon enclosing a filter plate (example).
Then, degas your solvent. In HPLC, bottled solvents for example are placed in the basket of the ultrasound bath while purging them with a steady, slow flow of argon to remove dissolved oxygen. Do this for your deionized water.
Weigh in $\ce{FeCl2}$ in your dry Schlenk flask, and add the deionized water prepared under the inert gas.
See if your group or an other (e.g., organic / organic catalysis) has a Schlenk line. With some training, this allows you to reduce the interference of oxygen greatly, because you may evacuate your reaction flasks and to replace the air by an inert gas such as nitrogen or argon. Nitrogen is relatively cheap because it equally is used for welding (as gas) or for cooling (think e.g., NMR spectrometers). Argon gas, on the other hand has the advantage of a density greater than the one of air, thus you may cover and protect your substance under a blanket of argon.
Then, search for Schlenk flasks. You identify these quickly for their connector to said Schlenk line. Besside round bottom flasks and tubes (a gallery, a second one), there equally are Schlenk flasks to perform a pressure filtration while working under argon enclosing a filter plate (example).
Then, degas your solvent. In HPLC, bottled solvents for example are placed in the basket of the ultrasound bath while purging them with a steady, slow flow of argon to remove dissolved oxygen. Do this for your deionized water.
Weigh in $\ce{FeCl2}$ in your dry Schlenk flask, and add the deionized water prepared under the inert gas.
More
VOTE