[curiouscat]

I'm supposed to design an experimental rig to measure kinetics of a vapor phase rearrangement reaction.  I've formulated some basic ideas of how to go about this but would love comments or sugesstions.

The reaction itself is fairly straigtforward A B but happens in the gas phase at around 600 C and a vacuum of ~100 mmHg (abs). We might also test an option to co-feed either N2 or steam to kill side reactions. The reaction is fairly fast with residence times of ~0.5 sec. 

Both A and B are high boiling organic liquids. Analysis protocols are well established.

Any sugesstions about what sort of rig to use? One option is to use an electrically-heated thin, long pipe to carry the reaction. Should I do it in continuous mode or batch mode?

I'm also a bit lost as to how to dose A / N2 / H2O accurately at these small flow rates.

[discodermolide]

I'm supposed to design an experimental rig to measure kinetics of a vapor phase rearrangement reaction.  I've formulated some basic ideas of how to go about this but would love comments or sugesstions.

The reaction itself is fairly straigtforward A B but happens in the gas phase at around 600 C and a vacuum of ~100 mmHg (abs). We might also test an option to co-feed either N2 or steam to kill side reactions. The reaction is fairly fast with residence times of ~0.5 sec. 

Both A and B are high boiling organic liquids. Analysis protocols are well established.

Any sugesstions about what sort of rig to use? One option is to use an electrically-heated thin, long pipe to carry the reaction. Should I do it in continuous mode or batch mode?

I'm also a bit lost as to how to dose A / N2 / H2O accurately at these small flow rates.

Have a look at flash vacuum pyrolysis systems.
http://www.fkf.mpg.de/125007/Pyrolysis_Furnace

[curiouscat]

Thanks discodermolide! That's exactly what I want to do; but unfortunately the page is a bit lacking on how exactly one would design such a system. Any pointers where to look?

[discodermolide]

Thanks discodermolide! That's exactly what I want to do; but unfortunately the page is a bit lacking on how exactly one would design such a system. Any pointers where to look?

Just search google for flash vacuum pyrolysis, or go to the library at the Uni.
A lot of equipment may be obtainable from suppliers, perhaps you can get ideas from their catalogues. Many people by the basic stuff and add their own modifications to suit their particular needs.
I personally have never had experience with such equipment.

[curiouscat]

Following up, there's some practical problems we are facing:

(1) Should we use a metering pump for liq. A and then force it into a vaporizer? The trick here would be assuring that all A vaporizes.  Or is  there a good way to meter in pre-vaporized A. 

(2) Is it feasible to use a chilled water / brine condenser to quench or would a liq. N2 trap be ideal?

(3) What's a good way to deliver a precise metered N2 flow in the lab?

[discodermolide]

You can get efficient gas and liquid flowmeters which are very accurate.
You can vaporise A after the meter or , which may be better, before and pass vaporised A through the meter.
A liquid nitrogen trap I think is essential then you will catch everything.