Sciencemadness Discussion Board

Feasible Reactions?

steil - 12-10-2010 at 17:28

I've been lurking these forums over the past few days and quite intrigued by the work that is going on here. I have been tasked with an undergraduate research project on amateur chemistry, focusing on the obstacles encountered and means of overcoming them.

I see many wonderful synthetic ideas here; however, it is quite easy to get lost in these long posts. I was hoping that someone would be willing to direct me to some syntheses you may have attempted that would be feasible in an undergraduate laboratory setting using crude reagents (i.e. over the counter consumer goods) on a small scale. My goal is to compare these improvised methods against the standard accepted methods.

The only request I have is that things of dubious legality not be suggested.

Thank you very much,

Steil

spirocycle - 12-10-2010 at 18:52

I asked a similar thing a while back, and was told to go to the "beginings" section

maybe a preparation of benzaldehyde from toluene?
theres a giant thread about it somewhere

spirocycle - 12-10-2010 at 18:52

I asked a similar thing a while back, and was told to go to the "beginings" section

maybe a preparation of benzaldehyde from toluene?
theres a giant thread about it somewhere

zed - 13-10-2010 at 05:44

Ummm. So, your premise is, there are obstacles?

Perhaps that is so. If so, foremost among them, might be the outlandish prices chemical suppliers charge for small quantities of fairly common reagents.

Of course, academic labs are saddled with the same problem.

Suppliers may ask as much as $100.00 for 500grams of Polyphosphoric Acid. That, is excessive.

What to do? Make your own.

From US5951831.Condensation.Polymerization.Phosphoric.Acid

From Monoammonium Phosphate....assisted by vacuum

When monoammonium phosphate was subjected to microwave radiation, the phosphate heated rapidly. Almost immediately after turning on the microwave oven, the monoammonium phosphate melted and began to boil. Analysis of the gas that was released, showed it to be a mixture of of both ammonia and water. Monoammonium phosphate is composed of 14.7% NH3 and 61.69% P2O5. After microwave heating for 10 minutes, the glassy material that was formed contained 4.1% NH3 and 77.2% P2O5. In heating the the monoammonium phosphate, temperatures are reached that exceed the decomposition temperature of ammonia in the presence of phosphoric acid. Thus, ammonia is released, forming phosphoric acid. This is polymerized to polyphosphoric acid. The melting point of monoammonium phospate is 190C and this temperature was reached very quickly.
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Longer heating, should produce a higher P205 content.

I can buy 500grams of food grade monoammonium phosphate, for less than ten dollars.


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[Edited on 13-10-2010 by zed]

[Edited on 13-10-2010 by zed]

RiP057 - 26-10-2010 at 19:02

I agree zed the best way to do things is DIY... any number of reagents is outrageous in price or in availability. Currently I have been looking for 2-meindole, and Aldrich has been out forever maybe they have it now but i think its back ordered

woelen - 27-10-2010 at 07:12

There are so many things you can synthesize at home, what kind of things do you want to know? I myself have made quite a few useful inorganic difficult to obtain reagents from easy to obtain chemicals like NaOH, pool chlorinator, dilute HCl, NaI, KBr, KI and KCl. I made
- potassium bromate
- potassium metaperiodate
- sodium orthoperiodate
- potassium chlorate
- potassium iodate
- bromine

I also made more exotic stuff like K3CrO8 (from KOH, K2Cr2O7 and H2O2), but K2Cr2O7 may be considered already as an uncommon reagent.

I have written web pages about the synthesis of the chemicals, mentioned above:
http://woelen.homescience.net/science/chem/exps/KBrO3_synth/... (with KI one can make KIO3 in the same way)
http://woelen.homescience.net/science/chem/exps/KIO4_synth/i... (can also be done with KI instead of KIO3, just use more KOH and more Cl2)
http://woelen.homescience.net/science/chem/exps/Na2H3IO6/ind...
http://woelen.homescience.net/science/chem/exps/raw_material...
http://woelen.homescience.net/science/chem/exps/miniature_ch...

zed - 27-10-2010 at 07:25

RiP057,

I once purchased 2-Methylindole from a major chemical company. The product that arrived was virtually worthless. So nasty, it couldn't be purified by ordinary methods.

Easy to make though. Acetone, Phenylhydrazine, ZnCl, and Sand. I think I left some links to the procedure somewhere here.

Refer to Vogel's Practical Organic Chemistry. We do have a copy in the Science Madness library.

[Edited on 27-10-2010 by zed]

RiP057 - 27-10-2010 at 10:26

synthesis of 2-methylindole is not the hard part I have no distillation setup at the moment so that is the hard part....purification....

as far as ordering 2-meindole I would only order from a reputable place as that sucker oxidzes so easily you will end up with a red mess if it is not freshly distilled and cold packed

also I have a copy of Vogel... very useful book but beilstien is WAY more useful.... also I like the synthesis of 2-methylindoles from phenylisopropylamines.... gives a good reason to have all those phenyl ethyl amines around.... :P

[Edited on 27-10-2010 by RiP057]

zed - 28-10-2010 at 17:02

Never had a problem with purification. The way I remember it, the version of the Fischer Indole Synthesis that I used, produced a nice clean, stable, product. Clean crystals, with a very slight green tint. Distillation was not required, and after several years, the crystals did not appear to have deteriorated.

I'll check my personal reference archive for the procedure I used.





RiP057 - 28-10-2010 at 17:12

I am a distillation freak, and I must admit I want crystal clear indoles when I am working on them, as I find that once the reaction begins its already started to discolor, and 2-meindole specifically is an [O] nightmare. I am looking into spending big bank on one of those all in one vigreux, condenser, and vacuum distillers 14/20 style. In my past work I always had to distill every 2-methylindole from the supply house. Fischer synthesis is easy and straight forward and for making 2-methyl indole some phenyl hydrazine, acetone, methanol, and some acid is great.... plus I dont think I could explain away a container of freebase amphetamine as synthetic starting material for 2-meindole, but it can be done....