[Jasim]

First of all, my apologies on cross-posting. I originally posted this topic in Citizen Chemist as I wasn't sure where to put it. I didn't get too much interest there and this section seems more appropriate.

I'm attempting to synthesis ferrofluid.

2FeCl₃ + FeCl₂ + 8NH₃ + 4H₂O  Fe₃O₄ + 8NH₄Cl


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I started by putting some steel wool into a large beaker with concentrated HCl. I stuck it on a stir/hot plate and heated gently with stirring. It took about half an hour or more, but the steel wool dissolved into solution, creating a light lime-green solution. I expect that this contains Iron (II).

I took some Iron (III) Chloride, reagent grade, weighed it out and put it into 1M HCl and mixed well. I took measured volumes of the green prepared solution and the Iron (III) Chloride and combined them into a large Erlenmeyer.

I proceeded to add, dropwise, ammonium hydroxide solution to the mixture. Upon each drop, the solution turned cloudy. I did this with the the flask on a vortexer being gently agitated. The agitation quickly dissipated the reddish-cloudiness seen after each drop addition of ammonium hydroxide.

Periodically, I attempted to test the pH for neutralization using 0-14 pH paper. This was a little difficult as the solution was a dark color from the Iron (III). I continued adding ammonium hydroxide until agitation no longer cause any change in the solution...The resulting solution was a cloudy, reddish-brown color.

I'm very certain I way over titrated as my solution when finished came up with an estimated pH around 10+. I'm concerned this may have been the cause of difficulty in the next step, but am uncertain.

I have a neodymium magnet, rated with a 45-lb pull force. My supposed magnetite does not react to the magnet. The steel wool was magnet reactive before the reaction.

I'm thinking I need to re-attempt the synthesis, actually using a burette this time and using more care.


Any input or other assistance would be greatly appreciated. After synthesizing the magnetite nanoparticles, I will need to use a surfactant to keep them suspended in solution. I was thinking of trying to use tetrabutylammonium hydroxide. I've see recipe list tetramethylammonium hydroxide and thought this might be a suitable substitute. If I need to heat it I will attempt to use a heating mantle or block as I can't seem to find a hotplate around here that does not have a stir magnet in it.