ReactIR. Infrared spectroscopy revives in the age of NMR.

We have a brand new Mettler-Toledo ReactIR 15 sitting in my lab. It is rather simple to use- just dip the probe in your reaction mixture. It needs a little LN2 to chill the detector. The software is reasonable, bearing some resemblance to iControl of the RC1 sitting a few meters away.

The instrument is used to follow the progress of a reaction by monitoring the growth or extinction of IR absorptions. What is interesting for the user is that it is not necessary to identify any of the peaks in the course of an experiment. The software can integrate absorptions and plot their change over time. The fingerprint region of the IR spectrum is put to good use in that it is a fruitful region for numerous absorptions to appear.

The thing is still new to us, so we’re early in the learning curve. The probe in use has a wave number range from 2500 to  about 650 reciprocal centimeters. It is possible to detect up to 3000 wave numbers with a different probe. The probe is connected to the interferometer by a fibre optic cable comprised of a silver bromide optical pathway.

The thing is the size of a coffee maker and costs as much as a used helicopter. The ATR probe tip is small enough to be immersed in experiments at the scale of a scintillation vial or a 5 liter flask.

What it brings to the table is the ability to follow the progress of reactions in real time for process optimization. Pulling samples and trudging over to the NMR for in-process checks is tiresome and time consuming.

One limitation is the electrical classification. As with other electrical devices you have pay attention to the NFPA classification of the space it sits in. The ReactIR 15 is class 1, but not division 1. If the instrument must be used in this space, there are ways to fashion an enclosure to get around this, according to Mettler. Have a look at your computer as well. If your computer throws sparks and coal cinders, you may want to keep it away from that pool of pet ether on the floor.

About gaussling

Gaussling is a senior scientist in the chemical business. He occasionally breaks glassware and has been known to generate new forms of hazmats. Gaussling also digs aerospace, geology, and community theatre. View all posts by gaussling

5 responses to “ReactIR. Infrared spectroscopy revives in the age of NMR.

  • Joe Q.

    We considered buying one at our shop, but the price was too high, and the person advocating its purchase too much on the bad side of senior management to make it happen. (He was later “downsized”.)

    • gaussling

      Oops. It is a bit spendy, that is true. Perhaps someday a bit of competition will bring the cost below $100k. It would be nice to see Agilent get into it.

  • Slawomir

    Do you actually need Div 1? If the pet ether is present on the floor only in an upset you could probably look into Div 2.
    On the other hand if the explosive/flammable vapor is present during normal operations then you probably would consider Div 1.
    (All disclaimers apply!!! – I am not licensed in this area)

    About the price – what you pay is mostly the service. The instrument is perhaps 1/3rd of the price. The rest is the time that the application scientist is happy to spend with you on the project. I (happily) used quite a bit of their time, too.

    I am not sure if I would want to buy just the instrument from Agilent only to have it serviced by a discount servicing company. This is not Agilent’s fault, just the result of their size and popularity.

  • Hap

    I would think that the area between 3000-4000cm-1 would be sort of useful – acylations and alkenylations would have diagnostic peaks there. Though spending $1e5 for a kinetics machine and using it as a TLC plate seems like overkill.

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