Sciencemadness Discussion Board

benzaldehyde from benzyl alc. PTC problems

buddhadude - 27-9-2016 at 12:05

I did a quick experiment just to get an idea of what problems l may in counter when I attempted to do this reaction. My computer crash and I lost the paper I had so I was doing this from memory. To 50 m! Of concentrated bleach, and .5 g of benzyltriethylammonium in 50 ml of ethyl acetate, then with stirring( I swirled in a mason jar) I slowly added .5 m of benzyl alc. The reaction increased in temp. but not dangerouly so. I swirled for 30 min.
I could smell benzaldehyde. I remember they used toluene to extract. I didn't attempt to separate.
I still haven't recover the paper yet, but i'm thinking of trying to do a simple distil onl the organic layer then using vacuum after ethyl acetate is removed to recover the benzaldehyde.
But to be honest it didn't smell as strongly as it should have. Should I neutralize the PTC first so its not in the organic layer? Even the paper I had was a little shy on this. Any insite would help a lot and I'll share my results.
I am set up now to do the experiment a little more efficiently now with mag. stirring and some lab glass, and an addition funnel. Thank for any input.

zed - 30-9-2016 at 12:07

Input? Find a usable procedure and follow it. Exactly.

Perhaps, check Youtube? Or, use the Science Madness search engine.

Guys have been working, to perfect procedures for producing Benzaldehyde, fer at least a hundred years. Guesswork, isn't gonna trump a hundred years of carefully developing successful procedures.

buddhadude - 30-9-2016 at 21:26

Of course your right. I just became inpatient is all. I've again recovered the paper I'm working from. I was way off on what I remembered from memory. I am almost ready to do the procedure as written, and then scale it up some. I'll post my results. The paper plus several other sources claim better then 90% yield in less them 30min. Including an easy work up. I have several PTC to try out. I've seemed to have lost my stir bars. So l may wait tell I can order a few more.

CharlieA - 1-10-2016 at 18:16

PTC??? Is that an acronym? Like Aleppo....:D:D:D

Metacelsus - 2-10-2016 at 05:55

Phase transfer catalyst.

CharlieA - 2-10-2016 at 12:35

Thanks!:):)