Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: asdfsad on April 13, 2009, 03:24:08 AM
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Hello everyone. I have a quick question and it would be greatly appreciated if someone could help me. I have already searched the internet, but have come up with no results at all.
I am performing a crossed aldol condensation reaction for my organic chemistry class. I have the structure of the product, but not the name of it. I essentially reacted Acetophenone with p-methoxybenzaldehyde. Does anyone know what the name of the product is? I would gladly provide the structure of the product of anyone needs it. I would ask my professor, but long story short I would much rather ask him as a last option.
** and little side question I wanted to ask
I did a TLC analysis on the product. I am sorry if this question is much too general, but other than analyzing the polarity of the product, what is the point of performing such a test?
TIA.
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Acetophenone + p-methoxybenzaldehyde => (2E)-3-phenyl-p-methoxyphenylpropen-1-one...Maybe you double check if it is correct.
TLC (Thin liquid Chromatography) is really used to find the polarity of the product...or calculate Rf value...It cannot represent both qualitative and quantitative analysis. Hence, it is quite useless...Separation may give qualitative analysis...but without known standard or suitable solvent with similiar polarity, you cannot identify it.
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The point of TLC is to provide a preliminary check on the purity of the product, and to monitor reaction progress. Usually when you run a TLC plate, you also make a separate spot for your starting materials, and then if available, a pure product. You run this TLC plate, and you can see where the spots for your starting materials are, and then if you see more than one spot in your product column, you know it is not pure. You can compare the impurity spots to the starting materials to see if the reaction did not fully complete.
And TLC can provide semi-quantitative information as well! You can analyze reaction mixtures and determine which products are major and minor sometimes. As an example, I've attached 3 pictures (as a .zip file, they were making this post huge). This is a reaction I did. P stands for product, BP is byproduct, and RM is reaction mixture. This reaction produced two compounds (P and BP). However, we thought that we could convert the BP to P by refluxing in water and methanol. You can see that TLC provided us a quick way to follow the progress of the conversion. The first plate has two spots for the RM that are roughly equal in intensity. The second plate, the bottom spot (the one we want), is now slightly darker than the top spot. By the third plate, you can see a clear intensity difference between the two spots. This indicated to us that this process had converted our BP to our P.
TLC is an great, quick tool for any organic chemist to have. There's even more that you can use TLC for. However, for most undergrad organic labs, the purpose of you doing TLC is practice and to follow reaction progress/check purity.
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Thank you so very much for your help. I will definitely recheck the name of the my product.
And macman104 thank you for the explanation. I had been doing TLC plates similar to the zip files that you attached in my organic lab, but unfortunately I wasn't given any rhyme or reason as to why it was done. It makes much more sense to me now.
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It turned out that isn't the correct name of the structure. Anyone else have an idea of what it could be called?
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(2E)-3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one
from chemsketch
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I just realized that chemsketch had that feature and I just used it. I got something similar to what you have posted. It wasn't the same, but I will check with my instructor. Sorry to *Ignore me, I am impatient* an old thread. Thank you nj_bartel.