Tuesday, July 14, 2015

Coincidences and Chicken Feathers

Coincidentally, I wrote just last week about how quickly the University of Illinois Alumni Association knew my new address. But yesterday, I got another piece of mail that also had not been forwarded, but instead had the new correct address. In this case, I was happy to see it, as it was from Patent Awards, announcing that a patent application of mine had issued. The company sells nice looking plaques for hanging on the wall with images of the first page of the issued patent. That's how it works in this country - the first time you find out about a patent issuing is not with an official government letter but when a company tries to sell you something. What was most shocking was that the patent had issued only last Tuesday. Was it possible that this company somehow in less than a week had seen the publication and also knew my new address? No, probably not. I looked at the file wrapper [*] on the USPTO Public PAIR website and saw that the notification for allowance was way back in early March, so they knew this was coming. Somehow they also knew my new address without me giving it to them, but I figure the Post Office probably sells that information.

The patent was from an application that I had filed back in 2012 when I was at Aspen Research. It involves the use of chicken feathers as a base for polymerizations. Chicken feathers are mostly a waste product that is largely ends up being buried. In the US alone, 4 - 5 billion pounds end up underground and so it represents a huge potential feedstock that is biobased and present around the world. That's at least 4 - 5 billion pounds of plastic that could be made, and more if the feathers are combined with other materials. We used to dream big and joke that the first 5 billions pounds would be free. After that:
Featherless chicken
"Eat more cowz!"
The feathers are about 90% keratin, a nasty crosslinked protein that, like most proteins, degrades upon heating before melting. The crosslinking is due to endless amounts of disulfide bonds. Attempts to plasticize them by solvating the disulfide bonds haven't worked out well in the past for a number of reasons. Being heavily involved in thiol-ene chemistry at the time, I was able to devise a scheme that worked with the disulfide bonds.

The Public PAIR website also showed that there was no office action - the patent sailed through unchallenged by the examiner. That's a first for me.

Coincidentally, I was just thinking about that chemistry yesterday before getting the letter. It's been a couple of years since I've worked with the stinky mercaptans, but it all came back when I read the latest installment of the Master Organic Chemistry blog on thiol reactions. James points out that mercaptans are analogous to alcohols in some ways (as would be expected), but not in others, particularly when undergoing oxidations. Alcohols are progressively oxidized to ketones/aldehydes and then carboxylic acids, while thiols are only oxidized to disulfides. I had never really given it much thought. Why aren't there -CSSH groups for instance? Apparently a C=S bond is rather unstable.

Update: As Joe Q. pointed out in the comments, dithiolcarboxylic acids (-CSSH) do in fact exist. A closer rereading of the James's post made it clear that thioketones and thiolaldehydes are what he was discussing, although they can be stabilized with an adjacent nitrogen or other functional groups, which was also mentioned by Joe Q.

[*] The file wrapper is an ancient term for all the paperwork associated with an patent application.

Previous Years

July 14, 2014 - A Novel Adhesive

July 14, 2010 - Chemistry and Music

July 14, 2010 - No RDA on BPA in the EU

July 14, 2008 - Accelerated Aging - Getting Bad Data Even Faster - 1st in a Series

July 14, 2008 - Playing the Building


Joe Q. said...

Dithiocarboxylic acids and their esters, thiocarbamates, etc. all do exist. Just not that stable to hydrolysis.

John said...

Thanks, I stand corrected. I'll make an update as soon as possible (I.e., NOT via my phone).

milkshake said...

By the way, how expensive are chicken feathers and pig bristles in ton quantities? You just gave me a brilliant idea for turning them into something of value.

John said...


Feathers are more or less free, but by the time you transport them, they can become very expensive given the low bulk density. i.e, build your factory next door to the chicken farm.

Pig bristles are already used for floor scrubbing pads, so they might have a non-zero value, but I can't say for sure.

milkhaken said...

you are right, chicken feather processing is bound to be messy, smelly and consume lots of water, so it would be worth building the plant right next to the meat processing facility.

Anonymous said...

Yes, it gives you something to do with all those naked chicks...