Open Access Journals - Beilstein Journal of Organic Chemistry

It's amazing how unpredictable life is. Only four months after I started my job in biotech I'm heading back to academia. Not that there was anything wrong with the job but I've been given an opportunity to return to Denmark (which always has been the long term plan) so I'm going with the flow. I recently had a post on open access journals and was moaning a fair bit about how we don't have any decent chemistry open access journals yet. Well I was wrong. A colleague alerted my attention to Beilstein Journal of Organic Chemistry (BJOC). This is the best attempt I've seen yet. They are publishing a reasonable number of papers, the quality of the material is good, the journal gets indexed by all the important organisations and it is absolutely free. The impact factor is still low (ISI WoK: 0.35) but this should improve with time. So check it out.

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The past year I've been involved in setting two labs up and whilst searching for information on equipment etc. I've been quite pleased with the Google adds people have on their web sites. I found a fair bit of the stuff I needed this way so I've decided to give it a go here at Curly Arrow. So sometime in the very near future adds will start appearing on Curly Arrow that should be useful to people interested in purchasing lab equipment. D!

Catalytic Hydrogenation - now fire free

In my experience you should not do synthetic organic chemistry if:

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(A) You are drunk (or the following day when you have a hang over)

and/or

(B) You are in a hurry

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Recently, I violated Commandment B and decided to put a large scale catalytic hydrogenation on really, really fast. Bad idea!

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Now hopefully most of you realise that the addition of palladium on charcoal (or charcoal alone) to organic solvents can result in instant bonfire. Unfortunately the chemists hand is often right above the flask as the catalyst gets added and some very nasty burns can result. Even worse the whole thing may take off and you'll frantically be looking for a fire extinguisher (Always know where the fire extinguisher is. You will need it one day).

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There is an easy way to avoid this problem. If you first remove all atmospheric air inside your flask there will be no fire. In other words what you have to do is flush the flask with nitrogen or argon. I normally hook my flask up in such a way that I can evacuate it with a pump and fill it with nitrogen. I've shown one of my recent setups on the picture. You can obviously connect things in many different ways depending on what equipment you have available.

I normally evacuate the flask and fill it with nitrogen at least three times. Only then do I proceed to add my catalyst. After addition I repeat the evacuate the flask procedure but this time I flush the flask with hydrogen and at the end I attach a big fat balloon with hydrogen gas and stir the reaction mixture vigorously.

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The other day when I was in a big hurry I decided to skip the flushing with nitrogen step (for the first time ever) and as a consequence I had my first Pd on charcoal fire. I was very lucky and didn't burn myself because the weighing paper was shielding my hand. The drama was quickly over as I had my lab book handy and sealed the flask with it. The hydrogenation worked fine and I made it in time to the pub. However, next time I think I'll skip the first pint with the boys and flush that flask as I normally do. D!

Recycling Silica Gel

Insert usual excuse for infrequent posting here: .....

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I recently received the following email regarding recycling of silica gel:

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"In the past we used to regenerate SiGel with fuming nitric acid, much as you do here (refers to previous post - D!) .Place the coloured, used SiGel (which of course must be uncoated and completely dry) in a large beaker. Approximately a third full. Place it inthe fume cupboard and pour in the nitric acid so the SiGel is completely moistened. If necessary, stir it. After a possible initial fuming has stopped, heat it on a steam bath for 10 minutes - leave it overnight. Next day, fill up with water, stir and let it settle. Wash 3 more times. At this point, it should be colourless, if not, repeat with more nitric acid. Then wash with satd. sodium bicarbonate until neutral and filter on a Buchner funnel. Wash with water, methanol and acetone and let it suck completely dry. Finally, activate by heating it in an oven overnight at 100-120 C.This way, it is as good as new for most purposes."

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This may be of use to some chemists working at institutions where money is very scarce. However, considering the amount of time and large volumes of solvent required to do this I think it can be classified as historically interesting but not practically useful to most of us.

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Nevertheless thank you for the email. I have wondered exactly how you would go about recycling your silica gel.

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Speaking of silica gel and techniques that are disappearing from the chemists hood check one of the most recent posts at In the Pipeline out. Derek seems to think that TLCs are on their way out as LC-MS is becoming more and more common. I believe that it will take several decades before Derek's predictions come true (especially in academia) but he does have some very good points. D!