Writing about: Group IV » Blog Archive » Tocil Wood
Tocil wood is lovely at the moment: all the bluebells are out and it’s an impressive sight. It’s very hard to capture the feel of these things – each flower is so small, it’s just a sea of blue…
The purpose of my trip to Brussels was actually to evaluate the performance of some of my compounds under a range of conditions, using a high-throughput reactor that our collaborator at BP/Solvay (now Innovene) have, called an Argonaut Endeavour
The endeavour is a nice piece of engineering, designed for high pressure, high temperature work, specifically “hydrogenations, carbonylations and polymerizations”. It allows you to run 8 reactions in parallel, under differing conditions. We ran 2 catalysts in each run, with the same set of 4 conditions for each, testing temperature dependence and hexene incorporation. The protocol we used involved pre-activating the catalyst with MAO before injection into the reactor, so it’s important whatever reacting the catalyst with MAO forms is stable for as long as it takes you to inject it into the reactor.
It is probably not realistic to test more than 2 catalysts in any given run, given this activation procedure, it’ll become difficult to keep things moving.
The biggest problem with this reactor is the design of the injector ports. BP have developed a way of injecting under an inert atmosphere, which is nice, but the reactor is clearly not designed for this type of operation. The injector ports are fiddly, delicate parts, and whatever you inject must pass through an extremely fine (0.5mm?) tube into the reactor [I believe that the fine diameter tubing is necessary to make it possible to inject against the pressure of the reactor].
The problem here is that if you inject aluminum alkyls such as MAO, once the inert atmosphere is removed, alumina forms on all the surfaces of the injector ports, requiring a complete strip-down of the injection system after each run. Further, it is easy for the narrow tubing to become blocked, either with alumina, or with polymer formed during the run. To unblock these tubes is a serious hassle, without guaranteed success. More to the point, occasionally an injector will block after the reactor is assembled; the first one knows about it is one is trying to inject the catalyst or solvent to start the run – in this situation it is impossible to unblock, and the result is that that vessel cannot be run.
During the run, the conditions within each reactor are monitored, and usually controlled well. On one occasion, the system failed to control the pressure of ethylene in a vessel to the required 10 bar, and allowed it to rise to the supply pressure of 15 bar; it is possible that the inlet valve had become blocked. In some further cases, the measured uptake of ethylene became negative. This must be an instrumentation issue. Basically, the uptake charts generated are probably more use as qualitative measures rather than quantitative. The really interesting data from the week’s work will be the final productivity numbers under these conditions, and the analyses of hexene incorporation and branching characteristics.
In one week, we conducted 56 separate polymerisation reactions, testing 12 catalysts under varying conditions. To do this work using Schlenk tests would probably have taken in the order of 2 months of solid work. There was some time overhead involved in shipping the chemicals to Brussels, and of course in the travel and time spend arranging incidentals to the trip, but nonetheless we collected a significant amount of information regarding our catalysts.
I just came back from a week in Brussels, working at the BP/Innovene/Solvay site – I’ll write about my work separately.
Due to some Seafood Expo, we were staying in a youth hostel in Anderlecht, called GĂ©nĂ©ration Europe – nice hostel, decent breakfasts, fairly rough area of town. A particular highlight was rolling up there in a BMW executive car! Last night spent in the Hilton Brussels – which was pretty much as expected for a 5 star business hotel. Excellent breakfasts.
Brussels is a great city if you want to eat out – there are so many nice restaurants, and many fit in the “decent, reasonably priced” category which is so hard to find in the UK. I especially enjoyed Le Paon Royal – an excellent bistro on the square by Église Sainte Cathérine. I had Chateaubriand with frites, which was excellent.
We also liked a noodle bar called Suki, on rue des Poissonners (near the Bourse). It’s a tiny place, but serves up really good noodles, rice, and pad thai – nice and cheap and very tasty.
The public transport system in Brussels is pretty good – a comprehensive network of trams and busses, which seemed to mostly run on time. The route to the site at which we were working was a mass of roadworks, which caused some delays (and shaken fists from the locals), but that was the exception rather than the rule. It is considered bad luck to have to wait more than 5 minutes for a bus during the daytime.
All up, a very enjoyable trip. More photos, as ever in my gallery