Vacuum grease…

[Rabidreject]

I’m sorry to make so many really simplistic posts - in fact I can’t really believe iv come this far without knowing some of this stuff but hey, live and learn eh?

So, what grease are you guys using for your joints?

iv been looking up vacuum grease and it seems to be crazy expensive - one of the only tubes I saw on eBay that seemed to be the sort of product I need was like £60 a tube…and I’m not even sure it is the correct stuff….

It is for the joints under reflux using ethanol as a solvent - for the moment but f knows what I’ll end up refluxing…well, I mainly do know actually. Pretty much phenethylamines, tryptamines (although not as much refluxing with that) and psychedelic amphetamines (probably not as many though as they tend to be SUPER long lasting!)

Im about to perform a nitroaldol/ Henry RXN on 2,5-DMOBA using ethlenediamine as a catalyst - although not hugely relevant to my question! Sort of…

It’s one of those questions that really will be used for any time I do distillations or refluxes….

I remember reading practical MDMA manufacture by Strike? Think it’s strike at least…may have been uncle festers book but one of the more notorious clandestine manufacture books said to use Vaseline but as far as I could tell when I was simply distilling ethanol (with a fairly low BP) you could see it was melting so I don’t know why he suggested it!
Maybe he just meant for the vacuum hose/nipple joints instead - I really haven’t read it since then!

Anyway I wondered what you guys use who aren’t working at a proper lab…I say ‘proper’ meaning registered with everything you need WITHOUT having to buy and risk your freedom to do so!

Actually tbf, if I can buy it and it’s cheap,; if it’s used in actual labs that’s probably better, there are some things us mere mortals can’t simply buy though!

 

[CCL4 huffer]

so like normaly i use none since if u destill smt the solvent or whatever shit should make it a bit wet and joints are not hard to get unstuck also some solvents or things can disolve grease or atack it possibly contaminating the product. u can also use like those teflon joint thingis ig or just teflon tape but propper dow high vac grease it not worth it unless ur using like schlenk or smt if u rl want grease just use vaseline or motor grease or smt. hope that helps a bit bdw if a joint is stuck slowly heat the joint up with a blow toarch and then let it cool down while slightly pulling on it.

 

[CCL4 huffer]

in general dont use grase if working with solvents like acetone or corosive shit like bromine or fuming nitric it will do nothing besides possibly make u have grease shit in ur product.

 

[Rabidreject]

Ah do you know what, it actually isn’t as much to do with them getting stuck, as it is I’m concerned with what may be escaping and creating a smell.
There is, however a bit of a story as to why - I think I was a little over worried about doing my first Henry / nitroaldol reaction lol

It’s the first time iv actually done a reaction at reflux in a while as iv been doing cold reductive animation of tryptamine. That as well as working with nitromethane just scared me into thinking greasing the joints was going to make all the difference when you leave the top open anyway lol I get there is a condenser and so technically things shouldn’t escape but I also wouldn’t really want to be breathing that shit in!

Im about halfway through the reaction and so far so good - looks exactly like the precursor to 2,5-DMA I have seen a guy perform this step of on YouTube (I believe he was trying to do this and fucked up and added nitroethane instead lol)
Either way, it gave me an interesting trick to try…this is besides the point anyway

But yeah that is more why I asked…it’s cool repurposed a grow fan to direct air outside anyway now and just sort of set it up in that room, check on it every 15 or so to make sure all is good and I’m not dead.

 

[CCL4 huffer]

nah its pretty mutch just not getting them stuck sum shit will always escape the joints vaseline or not if u rl want it sealed then just use teflon tape or these ptfe joint thingis but tbh rl the aperatus greases itself when refluxing or destilling

 

[Rabidreject]

Okay good stuff, will avoid grease - as I have been doing anyway!! Haha tbf, I actually even avoid oil baths atm for this reason just because I FUCKING HATE getting oil on everything! And it always go’s everywhere….
Therefore, I’m really glad you aren’t all saying “yeah you NEED grease!”

 

[Osmosis Vanderwaal]

Listen you need something in there. If not, the tiniest speak of anything will lock it terminally. Vacuum grease is fr Vacuum distillation, Vacuum dessication, vacuum reflux...stuff under vacuum. It only takes a dot the size of a pea. When not using vacuum I use chapstick that I have 20 of laying around or some wax and rub it on the frosting really hard. The fit is so tight that leaking isn't an issue once you have put it together properly. It's common to use way to much and make a mess. A layer 0.01mm thick is all it takes

 

[Loki12]

£60 for a whole tube of vacuum grease is a good deal. If you go easy and don't smear it everywhere excessively, a tube like that will last you at least a year (a year of working with the glass every day). For most amateurs, a tube is all they will need ever. You can use white vaseline or technical grease, however these can taint your product or simply boil off and create leaks when used with certain solvents (for example dcm usually dissolves shit grease real quick).

The laboratory vacuum grease is not only made to withstand chemicals so it will not boil off, but will also not react with other chemicals. The grease should be basic equipment for anyone that a) buys expensive glassware or b) does any kind of vacuum distillation. The amount of stuck glass on glass joints after distilling that you will encounter without the grease (or with using the cheaper options) will be huge. Once you break a piece that cost you over 100 euro trying to pull a thermometer adapter out of it, then you will go back and pat yourself on the head for not spending the 60 euro for correct grease.

 

[Osmosis Vanderwaal]

I've broke too much glass lately. I've had some successes at getting it apart too though. The freezer has worked better than heat for me I put water on the seams and heat the glass, then input it in the freezer, the water freezes and voila, comes apart

 

[Loki12]

Get a heat gun. The kind that is used to scrub paint, ball out and get an LCD display with the temperature.
1) You can now check the BP of your final products.
2) Use the heat gun to blast hot air on the joint. You should slowly, slowly see bubbles forming and flattening out. Put the glass upside down, but not too high (or use a blanket on the floor) so that the glass stopper or whatever you got stuck falls out. Keep blasting the hot air until it falls out.

With a professional heat gun it should not take more than 15 mins at most for situations like these.
I do want to repeat what I said, buy the vacuum grease, it will save you a lot of pain and wasted time.

 

[FENTAMAS]

@Loki12 is right. I can add that good glass joints will save you even more grease, time and equipment.
Something like DURAN® probably would be overkill, but there shouldn't be any gaps and backlashes, so that procedures like simple distillation could be done without any grease at all.

For me only pouring boiling water directly on to the joint works well every single time, any other method that gives slower increase in temperature couldn't provide sufficient temperature gradient between outer and inner joints.

 

[Osmosis Vanderwaal]

But it's really scary to run with nothing in the joints. They are ground of course, and fit so tight a medium size speck of dust will lock it solid if there is nothing on the joint. I always put SOMETHING on it. I'll rub a fucking candle on stand have. Chapstick anything to create even a micron sized space between the glass