We organic chemists have always liked the hydrogenation reaction. Take your compound up in a solvent, add a pinch of black catalyst powder, and put some hydrogen gas into the vessel. Come back a few hours later, filter off the catalyst, and there's your cleanly reduced compound, ready for the next step, often looking even better than it did before you ran the reaction.
For many decades, the standard ways to run these reactions have been to either take a balloon of hydrogen gas and attach it to the top of your round-bottom flask (as in this video clip), or run it on a "Parr shaker". That last piece of equipment has been with us, essentially unchanged, since the 1920s. It's simplicity itself: a thick-walled glass bottle for your reaction, a tube and stopper running into it (with a framework to hold it down under pressure), a hydrogen reservoir, and a motor to shake the bottle around. Its relentless dackadackadackadacka noise is one of the standard sounds of organic chemistry. These things are always off in separate hydrogenation rooms, and when you have several of them running in there at once the out-of-phase clatter makes sequential thought almost impossible. I wish that there were an audio file I could link to, but working organic chemists will all know the tune.
There are newer ways to run the reaction, and flow chemistry is the obvious choice. The "H-Cube" was an early entry into this space, and many of them are to be found around the chemistry world. Unfortunately, many of them are also found gathering dust. Uptake of the machine has been uneven, despite some obvious advantages. That's because the first-generation machine has some obvious disadvantages, too: you have to change the catalyst cartridge every time you want to try something different, because there's only one at a time. The cartridges themselves are not too large, so if your reaction isn't efficient enough, you can have a problem with not being able to run everything in one-time-through mode. And there's no liquid handling - you have to load your sample and collect it in whatever means you see fit. Various people have modified the machine over the years to get around these limitations, and the company now sells a machine incorporating many of these ideas. And there are competitors out there as well.
So here's my question for the chemical audience: has anyone had enough nerve to ditch the Parr shakers completely? I've heard of places that have done it, but when you inquire closely, you often find that there are still a couple around that do a disproportionate share of the hydrogenations. Are there any flow solutions that work well enough to get away with this? You'd think that there would be advantages to a walk-up instrument, if it were robust enough - put your starting solution in position A-3 on the rack, tell it what pressure and temperature you want, which catalyst to use, and add your run to the queue. Come back after lunch and there it is, eluted into another container, ready for you to pick up. NMR machines work this way, and so do microwave reactors. But do hydrogenators? Today, in the real world? Experiences with such things welcome in the comments. . .