Labour Day has come and gone, unofficially marking the end of summer 2013 . At least we have photos.
Natalie of Picture it Chemistry fame then went for a jaunt to the Bristol Botanic Gardens, for a look at natural product chemistry in its native habitat. There’s a nice tie in to the carboniferous forests of the distant past, highlighting how even modern oil-based reagents still ultimately stem from plants/animals/bacteria.
And now it’s back to the lab. If I missed your contribution to the carnival (or you have strong opinions on the difference between a canyon and a gorge), please let me know.
 The number of people on campus has increased by an order of magnitude, and every morning is cooler than the last. According to the calendar autumn starts in three weeks, but this far north I’m calling it early.
I haven’t been around much, and it isn’t a new postdoc that’s keeping me from blogging. I’m afraid the problem is more insidious.
You see, it’s really pretty out. Hike all day and sleep under the stars levels of wonderful, and if I’m not in the mountains I’m at the botanical garden or the farmers’ market . I’m not the only one getting out and about, and there’s quite a few people that we haven’t heard much from lately .
Luckily though, there’s just as much chemistry outside the lab as in it. So I say it’s time to host a ChemTravelCarnival, both to showcase what we’ve been up to and talk about everyday/holiday chemistry.
The carnival will kick off August 26th, running until September 2nd, Labour day. I’ll post a mid-point summary on Friday the 30th, and a wrap-up on Tuesday the 3rd.
1. The theme is “chemistry outdoors.” Depending on your lifestyle this may mean climbing Kilimanjaro, visiting a foreign country, or laying on the grass watching the clouds; all are great.
2. The more photos the better, but they are by no means required. Anonymous bloggers, remember to strip exif data, especially if the photo comes from a camera phone. There are a few guides online, but contact me if you need help.
3. Recent vacations are good source material, and there’s nothing wrong with a travelogue. Please limit yourself to material from summer 2013 though.
So dust off that old 35mm, grab your old Eastern European phrasebook, put on your best Hawaiian shirt, and get out there!
*No blogging experience or website required. Neophytes, send your stuff to Brandon.Findlay at Zoho dot com and I’ll put it up here.*
 Well, aside from all the plagiarism.
I’ve penned a guest post over on the Chemistry Blog. Check it out!
There’ll be a new post going up here in an hour or so, once I get some photos ready.
I’ve been exploring the darker areas of Sigma-Aldrich’s website lately, and I just wanted to highlight their technical bulletins.
A lot of them contain just what you’d expect, rather dry physical properties of chemicals and labware (ie. AL-223, Description of Pyrex Glass), but there are a few real gems. My picks, in numerical order:
**AL-134 Handling Air-Sensitive Reagents
AL-143 Mineral Adsorbents, Filter Agents, and Drying Agents (HTML)
AL-230 Pressure Conversion Chart (handy)
**AL-134 is a really nice intro to dry technique, filled with pretty pictures and all the rest.
 Have you seen their web toolbox? http://www.sigmaaldrich.com/technical-service-home/web-tool-box.html I could spend a good hour just reading up on different ways to give mice cancer. http://www.sigmaaldrich.com/life-science/cell-biology/cancer-research/learning-center/carcinogen-selector.html
Here’s a bit of a tricky situation. Every now and then I have a product which is clean, crystalline, and highly hygroscopic. I definitely don’t want to make more work for myself, redissolving the beautiful crystals just to pass them through a flash column, but every time I try to do a simple filtration I get a gooey mess.
The best approach in my experience is to run an inverted filtration, drawing the solvent away from the crystals under inert atmosphere. It’s not a terribly common technique, but I’ve been playing around with it over the last little while and I think I’ve got a pretty robust system put together. If anyone has run into this problem in the past though, I’d love to hear about your solution.
The basic design is cribbed from the advanced practical organic chemistry book, with a couple of modifications to fit it in with my glassware. In essence, the longest needle I can find is inserted backwards through a rubber septum, then lowered into the mother liquor. I stuff a little ball of kimwipe into the leur lock to serve as a filter, and generally try to use a 16G needle (anything up to a 22G will work, but the flow rate is really slow). The sharp end of the needle fits through another septum into a three way valve, which is either connected to the vacuum source or vents to the open air. A standard RBF at the bottom of the three way valve collects the filtered solvent.
For air sensitive compounds you can forgo the vacuum line in favour of a nitrogen source. I’m using a two-necked RBF in the example below, so I just attached the line with rubber tubing, but you could also think of double-piercing the septa of your solution flask. The key is to have a direct line from the gas source; putting a bubbler in the middle of the chain prevents solvent flow.