this is sheer speculation but it seems a number of different things effect the ketone color.  from the temp the ketone is distilled at, to the concentration and amount of NaOH washes.  never seen any varying in ketone color due to the extraction solvent (toluene vs dcm) before though, the crude undistilled ketone will be a different color yeah but after vacuum distillation it's all looked the same when using different extraction solvents.

lugh has it right, the ketone produced via peracid is higher purity because the wacker oxidizes to other ketones, etc, but it's in very very small amounts.  the only problem i've heard regarding ketone stability is from ketone produced via o2 wacker.  never heard of any problems from benzo wacker or peracid ketone.

yes it gets thicker consistency when kept in the freezer for awhile but the ketone will not freeze at regular home freezer temps.

Anyway the problem doesn't seems to be from the synthesis itself, as much as from the work-up/distillation....There should not be crystals in the ketone.

I don't know why, but I never had ANY safrole/Isosafrole comes over with the wacker oxidation.

Don't think Iso-olefin crystallizes when frozen...it may have just been that some of the original olefin from the very beginning did not convert (this could even happen if not enough oxidizing agent was used) and came over early on with the distillation, got into the 'tone, then crystallized at the bottom of the 'tone...where it will then begin to grow upwards. Sounds like it was some kind of contamination that does crystallize, that's for sure. If eugenol was left in, it will oxidize and go all the way thru the entire process yet it does not crystallize if it is still mixed in with the 'tone, it just causes a portion of inactive particles to result after an amalg. Even though it is inactive and tangy instead of super bitter...it does cause body load and some amount of body hangover. It sounds like just some of the original olefin got in there. A wacker is not perfect, even after reading the forensic studies, they found 5 to 10% of iso-olefin is always created. It's a very small percentage, but it is usually always there in some tiny amount.

Here is the only post I've ever seen on getting ketone to crystallize, this is from the old Hive:

Hellman:

In hindsight I believe that there was no need to crystalize the mdp2p, I believe its purity was sufficient. But i had to try it, next time I wont bother.

I created a cooling chest by slowly heating a drinking glass 500ml in the oven to about 300c(this can be done, the trick is o do it slowly) With this heated glass I submerged it ino a 20cm CUBED BLOCK of polystyrene(I was going to ozonate this styrene, but I will leave that to another day) Into the glass which had cooled-(smile), I poured my Co2/acetone/salt/ slurry, and ino that i placed my testube containing roughly 50ml clear as water Mdp2p,.
Being not a professional in crystallizing, It took me a while to get a seed crystal to start.

I furiuosly went through vogels, and realized that letting the substance warm just a little, then scratching it with a glass rod produced the seed that i was after,. Back into the ice chest it went, and back into the freezer,. And with 2 hours after that the whole testube was a crystalline solid, WOW,.(or for you american dudes-Neat-) I let it warm jst a bit drained the oil and refroze,.So, Yes you can crystalize Mdp2p, but after steam distillation, I don't believe that it really makes that much difference.

Good Info on melting points, and excellent question on whether any of them can precipitate out of solution.

i dunno but on a very good frezzer (dry frezzer) ketone got froze  might have to send pictures.
dunno what happened but getting ketone thats freezing 2 froze.... (its more like a slurpe in USA) so got blue slurpe, and now green slurpe.
didnt test the green slurpe but the blue one yield me 70% at al/hg. so i doubt thats isosafrole that froze or even water.
any thoughts?
peace

why some ketones are freezin? they become like a slurpe...like meshed up ice you know.... yield fine at al/hg.
it goes back to oil form very fast after take off freezer.

just wondering, why its happening, why its freezing. if it was really safrol or isosafrol my yilds on nitro al/hg wouldnt be around 70-80% i guess. seem many posts but no real conclusion. why the ketone is freezing. and just got blue ketone for the second time huahauha 

i just made some note.... when i got a complete reaction with p-benzo i have absolutly no left over p-benzo!!!! at all, only pdcl2. nothing besides pdcl2 to be filtered.
now.... sometimes i got some left  over p-benzo at final of reaction, (which led me to conclude that the reaction wasnt 100%).
*well, here, when i have a post benzo reaction with NO p-benzo left over.... the ketone "freeze" (like 7eleven slurpe)!!!
*the reactions that i had p-benzo left over.... the ketone doesnt freeze at all!!  maybe that will help  more knowladgeble bees to solve the matter. is afecting purity of ketone?

apreciate any thoghts..
peace

lugh sorry maybe you understood me wrong!!!
ive always know about isosaf being a side product os benzo wacker.....
what im saying is that if i have 100ml of ketone and around 70-80% is ketone, what i mean, is that the other 20% possibly isosafrole wodn´t be enought to crystalize so much, see the whole thing gets very thick with crystals, its hard to swirl even, i might be wrong but i dont think 20% isosafrole would make the solution so thick and so many crystals.
other ketone that i had crystals were like snow flakes and werent enought to make solution that thick! i hope i made myself clear.

and what i said is that the ketone thats freezing yield just fine like MM al/hg around 70-80%. so it cant be that much isosafrole. thats just what i think, ive read alot about these cristals, actually on this very same topic we stand on!!! thats why i posted here!! im just curious about the crystals formation and ive made a point that maybe is valuable about the p-benzo being all consumed or not, im very limited in chemistry, just though the info i had could be valuable!

for the ketone being like that would need at least 50% iso 50%ketone, but if that was the case the al/hg qouldnt yield 70%. am i right?

but i can see that you also have no idea why its freezing! thanks anyways!

peace!!

alright!!
i will try to give more detais next time, thank you.

 i distilled the ketone, my iso start coming at  135 so i let go up to 145 let it sit for a couple minutes,always collects the first maybe 70ml, then replace flask and continue destilation. so since i dont do a fractional destilation at least i try to catch some isosaf.
i will check the temp of my freezer, but i have to tell you, i have a ketone in the same frezer that has not froze at all!!! but others did. this is something that its not bothering me too much but i wonder the reasons behind it. ill try to colect more data as possible!!

thanks anyways!!

peace