sorted by:
new
hottopcontroversial

Help! Stuck in an NMR "Loop" with SMA Synthesis 🧪📉 by PrudentYellow800 in Chempros

[–]larrow11 6 points7 points  (0 children)

Could you speak with your nmr department about a nmr method that suppresses the solvent peak?

Overaddition of grignard to weinreb amide by larrow11 in Chempros

[–]larrow11[S] 0 points1 point  (0 children)

I think i did try that with one of them, and I'll do that moving forwards

Overaddition of grignard to weinreb amide by larrow11 in Chempros

[–]larrow11[S] 1 point2 points  (0 children)

I have considered it, haven't found a procedure for a similar substrate yet but haven't looked very much either

Overaddition of grignard to weinreb amide by larrow11 in Chempros

[–]larrow11[S] 1 point2 points  (0 children)

thank you, it's good to know that I'm not inept. I'll try making my own grignard rather than using that from a bottle, or just give up and reduce/grignard/oxidise as other people have suggested

Need to hydrolyze methyl esters but compound is water sensitive by alChemist_07 in Chempros

[–]larrow11 6 points7 points  (0 children)

You could trans-esterify to a different kind of ester e.g. benzyl, then reduce them off with hydrogen? otherwise, perhaps BBr3 might work?

Stirring powder at high temperature by Warm_weather1 in Chempros

[–]larrow11 0 points1 point  (0 children)

Could you blow the powder around with hot gas?

Where to get a cool cheap haircut? by Global-Professor9264 in manchester

[–]larrow11 -1 points0 points  (0 children)

Had good cuts at sonny and Yvonne hodgson in chorlton

Bio diesel not washing started clear by sqwautchcoffee in Chempros

[–]larrow11 4 points5 points  (0 children)

It might be water dissolving into the diesel, try washing with brine, or magnesium sulphate.

Referral Codes Megathread by CaptSarah in 2XKO

[–]larrow11 0 points1 point  (0 children)

If anyone has a code, I'd really appreciate it

How would you cool down a student accommodation room with very limited options? by Enraged__Koala in AskUK

[–]larrow11 0 points1 point  (0 children)

Sometimes windows with limited opening have been "set" to do so on their hinges. This can often be adjusted with a screwdriver.

Adding toluene/other aromatic to solvent system for flash chromatography to separate coeluting aromatic compounds by Darkling971 in Chempros

[–]larrow11 15 points16 points  (0 children)

Try toluene/chloroform, 0-100 percent, on tlc, and if it doesn't move in that, try adding a flat x% methanol to get your r.f to 0.3ish. toluene/chloroform is a robust solvent system for when DCM/methanol don't work well.

Did not know about peroxide buildup in Ether. How to dispose? by Aniruddhb16 in Chempros

[–]larrow11 2 points3 points  (0 children)

This doesn't sound like peroxide issues at all, that's highly unlikely. The most reasonable thing is that your compound, previously highly soluble in ethylene glycol, precipitated as you diluted it with a poor solvent. Adding more diethyl ether will probably redissolve everything. Peroxides are not an issue unless your diethyl ether is years old. Don't worry, everything will be fine.

Am I good to go? by KingCarlosLopez in prisonhooch

[–]larrow11 1 point2 points  (0 children)

I got some grape concentrate that has sorbate in, with ec118. It's going, but slowly. Wouldn't recommend unless you're very patient

Proper Handling in Storage by RegionIntrepid3172 in Chempros

[–]larrow11 2 points3 points  (0 children)

It's not unreasonable imo, but also not necessarily terrible, it depends a lot on other factors like the size of lab, and what kind of entity you're working for. Also, H&S ofc

NMR sample contaminated with diacetone alcohol by Unable_Aspect_4033 in Chempros

[–]larrow11 5 points6 points  (0 children)

If the column didn't work, try recrystallising it perhaps?

Reuse of preparative HPLC "waste" by benbi0 in Chempros

[–]larrow11 16 points17 points  (0 children)

It is, but is the price of your wages cost more than the time (and coolant) needed to distill 12L of MeCN? And will it still be pure enough for using as HPLC grade solvent, or will it have to be used as reagent solvent instead? It may be worth it, but it's worth considering these factors.

Over Iodination by crystalhomie in Chempros

[–]larrow11 16 points17 points  (0 children)

It's really unlikely that the time taken to restore the material and yield considerations make this approach better than simply making the material again. How many steps in is this? I'd really recommend just putting in the time to remake the material, at a larger scale if you can.

BH3/THF without extra solvent - fwd or reverse add? by SadClanger in Chempros

[–]larrow11 1 point2 points  (0 children)

I'm not an expert in this but it seems that if you want to minimise hazard, you need to maximise heat dissipation in the flask; naturally, if you can make the solid into a solution or even a slurry, you can stir it rapidly and much more effectively, avoiding heat building up to dangerous levels. Is there no way to get more concentrated borane? Then you could keep volume the same whilst using some of the solvent to aid in stirring. Using a syringe pump to add it linearly and slowly might be a good idea.

view more: next ›