03-11-02 03:12
No 280348
Swim while working on a experiment looked over just in time to see about 4 drops of saffola drip into 15g of pure Ketone from a new sythn he was trying. Swim dosnt want to distill it again. It was already double distilled and this was the product of a idea he had for a new wacker rxn. Any other way of getting rid of it and will it fuck up a amalgation. Swim sure hates to se his new creation thrown out.
(Chief Bee)
03-11-02 03:17
No 280351
The only way to purify it is to re-distuill it, but it doesn't matter if there is some safrole in the ketone, it will not interfere with the Al/Hg reaction.
(Hive Bee)
03-11-02 04:03
No 280366
Sorry I dont mean safrole I meant safflower oil used as a buffer.
(Old P2P Cook)
03-11-02 05:56
No 280431
I don't know why people insist on doing this. I see no advantage to using this so called "buffer" oil.
It shouldn't hurt the Al/Hg reductive amination.
(Newbee)
03-11-02 06:07
No 280442
>I don't know why people insist on doing this. I see no
>advantage to using this so called "buffer" oil.
Wow, reading this from you makes me really scratch my head (because I'm a newbee and thought I was on the right track, not because I think you're wrong). It was my impression from reading zubrick that adding a higher boiling oil to a (fractional) distillation helped to push all of the lower boiling oil up the column (a chaser basically). That and it would make cleaning the flask up later easier because there would be more liquid in it when done recovering the goods.
hmmm.
greeter
(Hive Bee)
03-11-02 06:38
No 280462
Normally swim does not use any buffer oil but this was a new syth - experimental and very small amount. Swim didnt have small enough glassware so used it only on first dist to seperate the ketone mix. It was needed because of the reactants involved. Actually the fucking bottle had leaked and a few drips happened to travel along shelf to land in beaker containing the ketone underneath.
(Hive Addict)
03-11-02 07:52
No 280507
The buffer oil isn't the same as a chaser oil. Buffer oil is supposed to keep from charring the stuff you're distilling. Never seen that happen unless it means the charred impurities, which are a bitch to clean out.
This chaser oil you speak of is used to heat the column packing and force the distillate over. You could do the same thing with a heat gun, or torch. Much easier.
Everyone falls down. It's how fast you get back up that is important.
(Old P2P Cook)
03-11-02 08:05
No 280512
Yep, what noj says.
(Chief Bee)
03-11-02 22:00
No 280776
This is chemistry superstition at its best - phlogiston anyone?
But seriously - couldn't someone here perform a real evaluation of the buffer oil practice? Next time you are going to distill your ketone, divide the crude ketone EXACTLY in half (use a good scale), and then you distill one portion with buffer oil, and the other without. Then weigh the distillate from each portion, and see if there is any difference in yield.
Performing the above experiment would be of MUCH help to you and other people here - so please try it, someone.
(Hive Bee)
03-12-02 01:45
No 280859
No Problem Rhodium. Havnt found much diffencence normally - actually It seams to adverselly effect it in some casses. Swim used buffer oil in this case only because of the size of rxn and didnt have small enough glassware to really get it going so really used it only to fill up volume of vessel. Using the buffer oil also does not allow any saving of any ketone if there is crud in vessel. Usualy if there is undistilled ketone crud in there swim will just make some sodium bisulfite solution throw it in there and save the resulting mass for next rxn. Swim has found it usually can give some substansial amounts of ketone back. Also swim will sometimes takes starting fluid that contains ether-hexane mix spray it in there right from the can and found that this will take up a lot of unsdistilled ketone in it. Then redistill that. This was just from a experimental wacker and this one didnt go as well as the last deffinatelly wanted to make sure of end product to see whatwent wrong. Last one got a 90%molar yield but this one barelly got 5% so trying to figure out where things went bad.
(Hive Addict)
03-12-02 10:09
No 281112
I tried using 100% peanut oil a couple times, but it seemed to make the contents foam excessively. Perhaps there was water in it?
Will try that next time Rhodium, just to see.
Everyone falls down. It's how fast you get back up that is important.
On second thought, it just makes no sense. How can an oil that is the same temperature as the ketone, prevent scorching? If the ketone is becoming vapor at say, 150C how could an oil at the same temperature cool it down? Either way, the last drop of ketone should still come over at its boiling point right?
It must be just a trick to help in the clean up afterwards. An oily matrix of crap would be easier to clean than dried crap.
(Hive Bee)
03-12-02 11:12
No 281145
The idea i believe is to use the higher bp oil to act as the cushion. As all the contents heat up - the ketone oil will be refluxing back into vessel along with a small amount travelling to the condensor. The higher boiling oil will sort of force it into the condensor as room needs to made for it as it expands and turns to vapor. Dont know if this is supposed to leave minimal time for ketone to be in a vapor state and keep it from refluxing back and cause possible breakdown. Swim has found no real difference in it at all-if good stirring is used it eliminates the need at all and swim has distilled plenty to virtually the last drop in distillate flask. But givin many poor distillation skills along with not enough insulation going to condensor blah blah many bees probally get impatient and crank the heat up charing the rxn contents. Swim guesses here that a buffer oil would be helpfull. Swim has a silver jacketed fractional condensor for extremely accurate distillations but it was to big to use for small rxn like this. He needed to add more volume to rxn vessel to allow it to distill over.
(Hive Bee)
03-12-02 16:44
No 281298
SWIA tried adding a little safflower oil while vacuum destilling final product (amine), per posts he had read, thinking this would prevent the blackened tar that is usually left in flask. After the fucking gunk foamed up and out of the flask and into the condenser, he swore never to try out anything he read on Hive ever again. (But then of course he calmed down and realized he didn't know a damn thing before he started reading Hive--the hard part is separating bullshit from fact.) So SWIA has sworn off adding any oil to his product--he believes it to be one of those myths that has never been debunked and removed from the sticky threads.
(Chief Bee)
03-12-02 17:03
No 281305
I feel that would be a good idea, as I don't believe anyone can prove safflower oil doing anything useful. One strong argument against this practice is that it is never used in professional "journal chemistry" settings - and with their usual reported yields after distillations should prove that buffer oil is not necessary.
Buffer oil may be useful for something though, I can imagine that the presence of a fluid in the distillation flask could prevent the usual brown gunk from polymerized byproducts from almost irreversibly adhering to the flask walls? Could somebody who have used oil confirm this? Is it generally easier to clean the flask?
(Hive Bee)
03-12-02 17:33
No 281311
Rhodium Swim has found that the buffer oil does not stop the gunk in glass. It will usually just get trapped in there along with the rest of the matrix of junk. It might make it a little more fluid-but mostly either it gets trapped or the buffer oil will end up sitting atop the black crap. And it dosnt really help speed up distillation. Swim has found that if you put rxn vessel in freezer to cool down then just when it gets cool enough to handle hit that crap immediatelly after with a hexane-ether starting fluid quickly then shove it back in the fridge for a couple of days then the solvents will eat away at that crap and actually take in some ketone along with it. You can actually recover some of it. Or if it is not too far to tar pour in some sodium bisulfite. Swim has recovered enough ketone from such to make it worthwhile.
(Daddy)
03-15-02 13:04
No 282968
It's an urban legend, since the days of Eleusis. Forget it. Thought I had it removed from sticky threads, have not looked in there for a long time. Seems it needs some attention, to fit the latest thoughts in there. Sticky's have been re-imported a few times I see, the whole posting order is upset. LT/
WISDOMwillWIN