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Re: Cracking of Dicyclopentadiene to Cyclopentadiene

Tue, 24 Apr 2018 20:11:18 GMT

I know Arkcon, that's true, I totally agree, but unfortunately things in Macedonia don't work that way. It's a bit  silly, they ask us to make something, don't have all the necessary stuff, so we have to make our own solutions, find alternatives. Sad, but true.



Re: Cracking of Dicyclopentadiene to Cyclopentadiene

Tue, 24 Apr 2018 20:05:32 GMT

Yes, of course I talked to my supervisor and to the lab assistant. I asked for nitrogen. They said I will have to synthesize it, because we don't have nitrogen.



Re: HELP, Williamson ether synthesis, masters deadline!

Tue, 24 Apr 2018 20:03:09 GMT

I like Finkelstein reactions, but I find them most useful in converting an alkyl chloride to something else. Bromides and iodides are generally well-behaved in my experience and I don't think that's the problem in your reaction.

First glance I noticed what everyone else did, I would ditch NaOH. If you're not getting E2 elimination then you're likely substituting with the OH anion instead, which would be difficult to detect by any method besides mass spec. You also run the risk of hydrolyzing your ester to a carboxylic acid.

Alkoxide formation is generally accomplished with NaH in either THF or DMF as someone else noted. I default to THF because it's easier to remove, but if you're having solubility issues then DMF is a good choice. I also use the NaH dispersion in mineral oil (60%) and don't wash it first, I've had no problems following that method. Stir NaH with your alcohol for 30 min to 1h at low temp (try 0 degrees first, but if it is too reactive then -78 degrees). Add your alkyl bromide slowly and let it warm up to room temp.



Re: Cracking of Dicyclopentadiene to Cyclopentadiene

Tue, 24 Apr 2018 19:48:59 GMT

You could also get another school to lend you a nitrogen generator, basically a system that pulls air over an oxygen consuming reagent and gives you clean dry nitrogen.

When a chemist needs nitrogen, they get it from a tank or the atmosphere.  Finding the most energetic nitrogenous compound, and decomposing it, carefully, to get nitrogen gas is beating a wasp's nest with a stick because you need a sheet of paper.



Re: Cracking of Dicyclopentadiene to Cyclopentadiene

Tue, 24 Apr 2018 19:30:05 GMT

If you are doing it as a part of your course it is not up to you to buy the chemicals, it is up to the school to provide you with the necessary reagents and hardware. Have you talked with your supervisor?