[jmwq]

So for my Organic lab the teacher gave us a product and we have to come up with the procedure. The product is 2,6-bis(4-methylbenzylidene)cyclohexanone. I need help in saying if the procedure can work.
The 3 reactants that I have is 4-methyl benzaldehyde, cyclo-hexanone and sodium hydroxide.

Procedure: In a test tube place 2.o ml of 2.0M aqueous sodium hydroxide, 1.6ml of ethanol, and .20ml of 4-methylbenzaldehyde inside of it. The add .07ml of cyclo-hexanone. Cap the tube immediately and shake. If two layers form  or a yellow precipitate does not form after 2 min add more ethanol (solvent). COntinue to shake the tube from time to time for the next 15 mins. Cool the test tube to room temp.

Vacuum filtrate using a buchner funnel and then recrystallize

[Dan]

we have to come up with the procedure.

I need help in saying if the procedure can work.

If you have come up with this procedure, can you tell us how you came up with it? Presumably you think it will work if you have suggested it as the answer to the question - tell us why.

[jmwq]

For the lab we where given a general procedure to follow by and we had to make modifications with this compound. The reactants however we came up with, from the general adol condensation reaction formula

[jmwq]

What we really want help with is determining what amounts of our solvent and NaOH to use in this procedure as well as what recrystallizing solvent to use (we think possibly toluene?). We also need to make sure we use enough of the reactants to get a 90% yield. Help appreciated. This is one of our final projects for our o-chem lab.

[Dan]

Ok, the purpose of the exercise is probably to precisely transfer the conditions of the original procedure to the new reagents.

Can you post the original procedure on which you are basing this new one on so we can compare them?

It is impossible to say whether the procedure will give >90% yield, there are too many unknown factors, like reaction rate, product solubility etc. This is why I suspect you are really being asked to show how you would apply the original procedure you were given to different starting materials.

In reality, when conducting an experiment you would normally monitor the progress of the reaction and stop it when it is complete, not after a previously specified amount of time.

[orgopete]

You should determine the number of moles of each reagent in the example procedure. Then use the same molar ratio for the new reagents to make the new product.

[jmwq]

The example procedure beginning was::
Add 2 mL 2M aq NaOH solution. and 1.6 mL of ethanol to a test tube. Then add .2 mL of benzaldehyde. Rince the syringe with acetone. Discard acetone used. Add .07 mL of acetone to the reaction mixture. Cap the tube immediately and shake vigorously. If two layers form or a yellow precipitate doesn't form after 2 min you may need to add more solvent or heat your reaction in a hot water bath respectively. Continue to shake the tube for the next 15 minutes. It may take longer or less time--check amount and rate of crystallization. An optimized procedure will use the shortest time necessary for a 90% yield. Cool. Scratch if doesn't recrystalize

Then it goes on to to vacuum filtration and recrystallization "choose a solvent" We have always used water but should we use toluene because it's an aromatic? Then it goes on with the specific procedure for a recrystalization with heat and vacuum filtration again. "In a typical experiment the yield would be 0.1 grams"

[orgopete]

Okay, that is the procedure. Would the weights and volumes change if you use different starting materials?