having used tFSE and found this thread to be most appropriate, aproblem is presented for which any advice or suggestions would be greatly appreciated.
Vac distilled saf via 500mm vig column comes over @ 12-114 with vac utiliezed(takes a while but purity is great 1st time). Used O2/IPA wacker with 50 ML saf. Thorough clean up (ie, acid wash, DCM of aq layer, poled extracts, Bicarb wash, 2X h2o wash, NaCl wash, dried 1hr MgSo4, set up for vac dist).
The following occured: Boiling stones and stir bar were used. DCM pulled of at 40 C atmospheric for most, then under lower vac, all at 40C. Oil bath temp increased steadily (during DCM dist the oil temp was @ 60 and increasing) to 155 C. At 119-121 C flourescent yellow distillate began coming across. After only a few mils the temp dropped to 115 and dist ceased.
It wsa clear that there was further product to be extracted. The vacuum was checked and operating efficiently, no leaks, no cracks. There was little or no bumping with the spin bar going (there were a few boiling stones present for good measure). The oil temp in saf ditil was 138C and it came over at 112-114, as mentioned.
It was expected that the (ketone?) would arrive at 150-155, yet it showed at approx 120.
Now, setting aside the possiblility that the wacker was incomplete ( it is realized this is a possibility), if the ketone was present, as it seemed, what possible problems are taking place? If the sas arrives at 114, is it possible this was not ketone since the temp was only marginally above the alkene temp?
Realizing that there are many other factors at play, if it is assumed ( a foolish, terrible word in chemistry!!) all factors were corect, what can be done ?
WSill bisulfite determine ketone presence? Can a higher boiling oil be added to aid extraction?
Will bisulfite serve to ppurify it enough to salvage it?
Any input would be greatly apprecitated.
