I will help you as much as I can
1. Wacker: What's the ideal length of a reflux column for this type of reaction? I've got a 400mm, would that work? What are the drawbacks/advantages to varried lengths available?
For a benzo wacker, any type of column would work. That is because you dont want to run it at a huge reflux, just very low. Of course if you need to buy a condenser, get it as long as you can, its always useful for refluxing. Anyway if you proceed to try MM nitromethane write-up, you will need a 600 mm length condenser because it refluxes so hard. Allinh type condensers are great for refluxing, Liebigs are for distillation. I found that running the wacker at around 60-65 is perfect which is just about the bp of the solvent, so it doesnt reflux hard, almost not at all.
2. It is said that a 2-neck RBF should be used. How about a simple RBF with a Claisen adapter? In which case which of the two necks should have the reflux column & which should have the addtion funnel? (I'm guessing the one directly overhead for the addition funnel - figured i'd ask to make sure)
No!!! You can use a Claisen instead of a 2 neck no problem but its the refluxing column that goes directly above your flask. The addition funnel is placed on the side adaptor.
I would suggest you get this book:
The organic Chem Lab survival Manual by Zubrick. Its essential for basic techniques, especially when your starting.
4. Finally, as far as vacuum sources go - I've seen a couple of "air condition" type pumps, putting out around 27-29" of vacuum. Can these be used for a reliable vacuum source? (seeing as the pump would have to run for quite a few hours at a time) What are some low-budget (but not totally bankrupt) alternatives?
You want a pump that pulls at least 27 inches, not anything below if you can. A lot of different pumps can be used, including a fridge compressor. HVAC pumps for air conditionning systems are great. Or just any vacuum pump make for labs and stuff. Your best bet would be an auction site, where u can find tons of pumps and you can make great bargains. My pump was bought of an auction site, cost me 50 bucks, pull about 29 inches. These pumps are made for continuous running and most have a thermal switch that turns the pump off if too hot. It's never happen to me, even after running the pump for 8 hours. The only drawback of such pumps: they can be real noisy
As for nitromethane, I cant help you, mine is 99.9% Nitro so I dont need distilling.
One last piece of advice. If you run MM benzo wacker, skip the saturated NaCL washes. Do 3 brine, 3 X 5% NaOH, then 2 water washes. Make sure you combine the water washes and put them back in the sep funnel to get some extrac DCM out.
Saturated NaCL is hard to separate from the DCM and you loose a lot of solvent and therefore product in the end.
Make sure you make the water washes after the NaOH. This is to make sure that you have no NaOh whatsoever left in the dcm. Other wise, you will loose some product that will polymerize when you try to distill it. I usually get about 125 grams of ketone that way. My last run afforded 154 grams so I can complain.
Hope this helped