I just had one of the first years make a boat load of the starting material he and I will both be using for our projects over the summer. He scaled up enough to use all of the remaining iridium (Ir) which was in the department, meaning that if we ever need to make this material again, we will have to buy more Ir. Iridium is pretty expensive, at the current market prices it costs just a tad under the price of gold, but that doesn't reflect the actual obtainable price because there are a lot more people out in the world dealing gold than iridium. Strem will sell the hexachloroiridate salt for 50$ per gram.
I've embarked upon recycling the iridium waste in the division for both practical reasons as well as pure interest in the brute force methods required to recover iridium residues back into usable materials. The procedure is basically this:
1. collect the waste
2. evaporate the low boiling solvents (<100 degrees C with partial vacuum)
3. evaporate the high boiling materials (heating mantle at about 300 degrees C)
4. fire the residues to ash (Bunsen burner with the air mixer open pretty far)
5. crush the ash and fire to redness (Meker burner with the air mixer open as far as possible.)
That gets to the raw metal, which is where I'll leave it for now. I think this whole process is pretty interesting, so I'll keep the individual steps updated on the blog. The method isn't proprietary and can be found in "The Journal of Less Common Metals", a tome of which I have never seen nor heard of until I starting this process.
June 23, 2007
June 21, 2007
glassblowing and joint sweating
Glassblowing is necessary from time to time in order to fix something you just broke, make a piece of glassware which you need right now, and so forth. Our glassblower arrives biweekly, so if you want something done by him it usually takes a long time, which could be remedied if the physics shop (which houses the glassworks) would just let us use the damn annealing oven.
We needed a piece of tube with a 3/8th inch outer diameter attached to a length of 1 inch tube with a standard taper 24/40 joint. This is nothing more than a tube, attaching one end straight on to the other. I tried for some time to make the first attachment to no avail. I could get as far as blowing out the end of the tube to make an even edge, but I was completely inept at attaching the two pieces. After several poor attempts Professor Heller learned of what I was doing, and although he thought it was admirable, was quick to point out exactly where I was failing.
I was missing a swivel joint used so that you could blow into a tube connected to the end of the glass and spin it at the same time. I distinctly remember that the last time I watched Heller connect two tubes together he did it without the aid of the swivel joint and did just fine. Apparently he was just showing off.
Hand annealing is another issue entirely, as Heller doesn't seem to have the patience to do it properly and as stated earlier, the physics shop doesn't let us use the oven. So even though the piece has been made it still can't be used because its too brittle in the present form.
On a similar note, sweating a joint in copper tubing was also on the day's chore list. I've seen my father and grandfather do it several times. The made it look ridiculously easy, just polish, flux, and sweat. This is a lot easier if you remember that you need the flux, which I forgot about on the first several attempts. I read on line that if you were doing this on household plumbing the best way to keep the water out is to jam a wad of white bread into the pipe before you sweat the joint, then just flush it out after you're done.
Curiously enough chemical stores does not stock white bread.
We needed a piece of tube with a 3/8th inch outer diameter attached to a length of 1 inch tube with a standard taper 24/40 joint. This is nothing more than a tube, attaching one end straight on to the other. I tried for some time to make the first attachment to no avail. I could get as far as blowing out the end of the tube to make an even edge, but I was completely inept at attaching the two pieces. After several poor attempts Professor Heller learned of what I was doing, and although he thought it was admirable, was quick to point out exactly where I was failing.
I was missing a swivel joint used so that you could blow into a tube connected to the end of the glass and spin it at the same time. I distinctly remember that the last time I watched Heller connect two tubes together he did it without the aid of the swivel joint and did just fine. Apparently he was just showing off.
Hand annealing is another issue entirely, as Heller doesn't seem to have the patience to do it properly and as stated earlier, the physics shop doesn't let us use the oven. So even though the piece has been made it still can't be used because its too brittle in the present form.
On a similar note, sweating a joint in copper tubing was also on the day's chore list. I've seen my father and grandfather do it several times. The made it look ridiculously easy, just polish, flux, and sweat. This is a lot easier if you remember that you need the flux, which I forgot about on the first several attempts. I read on line that if you were doing this on household plumbing the best way to keep the water out is to jam a wad of white bread into the pipe before you sweat the joint, then just flush it out after you're done.
Curiously enough chemical stores does not stock white bread.
June 15, 2007
clean
The lab has been cleaned. This ordeal took two days with 5 diligently working lab mates and a couple of lazy sacks who pretended to care and only took the time to clean up their own personal messes. I try not to cuss a lot in this blog, so I won't comment further on the efforts of the lazy sacks. The lab is now just about as clean as a lab with a clean group would have it when it was dirty, and I think I'll have to settle for that. The real score comes in counting how many incidents there were, in which we scored very well. While cleaning and disposing of over 300 different containers with poor or non-existent labels, there were no occasions of damage to person or property. Broken glass, while amounting to several decently sized boxes, did not result in any cuts or glass dust inhalation. The main source of excitement came while cleaning out a badly degraded bomb flask which used to contain KCp* (a commonly used ligand). The usual routine, starting with an iPrOH quench followed by EtOH followed by MeOH followed by water, failed. The remaining potassium in the flask did not react until the water had been added, causing the entire flask to smoke for a minute or two before catching fire or an additional minute or two (a nice bright yellow flame, quite pretty actually if your not distracted by the fact that the flask could explode momentarily). This prompted detaching the D fire extinguisher from the wall and rushing it over, although its use was never necessary. It did, however, warrant a date change on the wall for "Days since last lab fire" from last August to yesterday.
A note on fire extinguishers: There are three commonly used types, A, B, and C, which are distinguished by their contents: water under pressure, compressed CO2, and a chemical flame retardant. Most people are aware of the difference because they have been told that spraying compressed water on an electrical fire is a poor idea. Just to show why a type D is necessary in this lab, consider that the fire started BECAUSE we put water (a type A extinguisher) on the metal. A type B is CO2 and no, using a type B is not going to cause global warming, but letting your house burn down will. We can't use a type B here because concentrated CO2 is an accelarant for combustible metals.
I don't know why type C doesn't work, but I'm guessing that the chemicals in a type C react similarly with the burning metal. Type D is just powdered NaCl (table salt) with high pressure argon gas. Think of it as the most expensive salt shaker money can buy.
A note on fire extinguishers: There are three commonly used types, A, B, and C, which are distinguished by their contents: water under pressure, compressed CO2, and a chemical flame retardant. Most people are aware of the difference because they have been told that spraying compressed water on an electrical fire is a poor idea. Just to show why a type D is necessary in this lab, consider that the fire started BECAUSE we put water (a type A extinguisher) on the metal. A type B is CO2 and no, using a type B is not going to cause global warming, but letting your house burn down will. We can't use a type B here because concentrated CO2 is an accelarant for combustible metals.
I don't know why type C doesn't work, but I'm guessing that the chemicals in a type C react similarly with the burning metal. Type D is just powdered NaCl (table salt) with high pressure argon gas. Think of it as the most expensive salt shaker money can buy.
June 1, 2007
update
After some gentle urging from an adoring fan, a quick update, although not much of interest has happened.
I've been working carefully on two projects, a new ligand synthesis, and isolating some final compounds for what I hope will soon become a complete body of work, ready to be written up and published.
The new ligand synthesis is slow, as stated before its only useful solubility is in pyridine, and once the deprotonation is accomplished it is no longer soluble in this either. After trying to get the arms on the ligand it resolublizes, but only to show in NMR that the deprotonation was not complete, even after overnight sonication. The solution in this case is the cook it good and hard for a couple days. So that is where my NMR tube sits right now, trying to deprotonate the starting material, bathed in 120C oil, bumping away.
The other final synthesis I have been messing with has been postponed until I can completely purify the starting materials. Its this kind of fervid obsession with purity is probably the cause of most OCD which chemists experience outside of the lab. For instance, I am constantly skeptical that the dish washer we have actually gets the dishes clean. This is a manifestation of a fear that my lab mates simply rinse their glassware and place it on the drying rack, which requires me to wash every piece of glassware I use thoroughly before I use it, even if I pull it right out of the drawer.
Some of the booted material has gone from red to deep blue-green, and partially soluble in hexane. I've thrown together some crystallization chambers to see what's really in there after my stuff hits the air. One is a slow evaporation of a saturated hexanes solution, the other is a vapor diffusion of hexanes into a nearly saturated THF solution.
On the positive side of things, the lab has acquired a wiffle bat and some wiffle balls. The good weather and large lawn outside the chemistry hall has drawn us out on several occasions to take our frustrations out on each other in a non-deconstructive manner. I highly recommend this for graduate students everywhere.
I've been working carefully on two projects, a new ligand synthesis, and isolating some final compounds for what I hope will soon become a complete body of work, ready to be written up and published.
The new ligand synthesis is slow, as stated before its only useful solubility is in pyridine, and once the deprotonation is accomplished it is no longer soluble in this either. After trying to get the arms on the ligand it resolublizes, but only to show in NMR that the deprotonation was not complete, even after overnight sonication. The solution in this case is the cook it good and hard for a couple days. So that is where my NMR tube sits right now, trying to deprotonate the starting material, bathed in 120C oil, bumping away.
The other final synthesis I have been messing with has been postponed until I can completely purify the starting materials. Its this kind of fervid obsession with purity is probably the cause of most OCD which chemists experience outside of the lab. For instance, I am constantly skeptical that the dish washer we have actually gets the dishes clean. This is a manifestation of a fear that my lab mates simply rinse their glassware and place it on the drying rack, which requires me to wash every piece of glassware I use thoroughly before I use it, even if I pull it right out of the drawer.
Some of the booted material has gone from red to deep blue-green, and partially soluble in hexane. I've thrown together some crystallization chambers to see what's really in there after my stuff hits the air. One is a slow evaporation of a saturated hexanes solution, the other is a vapor diffusion of hexanes into a nearly saturated THF solution.
On the positive side of things, the lab has acquired a wiffle bat and some wiffle balls. The good weather and large lawn outside the chemistry hall has drawn us out on several occasions to take our frustrations out on each other in a non-deconstructive manner. I highly recommend this for graduate students everywhere.
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