[curiouscat]

We were running a Liq. phase sulphonation reaction in a mechanically stirred (500 rpm) 1L-flask so far but now are in the parameter optimization phase where we need to try a lot of different combinations of Reaction variables (dilution, pH etc.)

I'm wondering whether a orbital (or linear) shaker with, say, 10 vials or Conical Flasks might be a good way to speed up the experimental process? Any pitfalls? Or any other ideas or equipment suggestions are very much welcome.

How's the mixing in a orbital shaker versus a stirrer; any correspondence rules? I'm a little concerned because under certain conditions our's is a immiscible Liq-Liq reaction so not sure if a shaker would still be sufficient to mix.

Finally, is there a way to effectively cool a shaker? Some desired parameter levels need freezing mixture temperatures.

[fledarmus]

You might want to look at reaction blocks if you can test on smaller scales and if magnetic stirring is sufficient. Here are some that I like: http://chemglass.com/product_view.asp?pnr=CG-1991 but there are many other geometries available.

I've found magnetic stirring generally more effective than shaking for two-phase systems - orbital shakers are pretty poor for those. Unfortunately, neither is nearly as effective as mechanical stirring with the right paddles. As for cooling, many of the orbital shakers available now have built in liquid cooling systems which are very nice, but I've been able to get away with setting my reaction blocks in an ice bath and still have sufficient magnetism to stir them through the additional distance.

[BobfromNC]

Put the entire shaker in a cold room or freezer.    I used to do small arrays often, and scint. vials are good for them, or even 100 ml bottles, depending on the scale.  There are many reaction blocks out there, but a Weaton vial rack with 1, 2, or 5 dram vials works just fine, and many orbital shakers are strong enough to keep the reaction well mixed.   

[curiouscat]

Thanks for the tips! Here's one wacky idea; would it work: We have an under-worked lab centrifuge lying around. Is that an option for running reactions in? Or disaster? Any comments? Would the two Liq. layers segregate and not react much or would the high-g forces give better mixing?

[BobfromNC]

Lab centrifuge will not agitate the reaction, and will make it worse than nothing, most likely.  That is designed to separate components, not mix them.  Any sort of shaker, rotator, or stirrer would be better.