A step towards new nitrogen products | Hacker News Reader

A step towards new nitrogen products

news.yale.edu

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https://www.nature.com/articles/s41586-020-2565-5

The activation of abundant molecules such as hydrocarbons and atmospheric nitrogen (N2) remains a challenge because these molecules are often inert. The formation of carbon–nitrogen bonds from N2 typically has required reactive organic precursors that are incompatible with the reducing conditions that promote N2 reactivity1, which has prevented catalysis. Here we report a diketiminate-supported iron system that sequentially activates benzene and N2 to form aniline derivatives. The key to this coupling reaction is the partial silylation of a reduced iron–dinitrogen complex, followed by migration of a benzene-derived aryl group to the nitrogen. Further reduction releases N2-derived aniline, and the resulting iron species can re-enter the cyclic pathway. Specifically, we show that an easily prepared diketiminate iron bromide complex2 mediates the one-pot conversion of several petroleum-derived arenes into the corresponding silylated aniline derivatives, by using a mixture of sodium powder, crown ether, trimethylsilyl bromide and N2 as the nitrogen source. Numerous compounds along the cyclic pathway are isolated and crystallographically characterized, and their reactivity supports a mechanism for sequential hydrocarbon activation and N2 functionalization. This strategy couples nitrogen atoms from N2 with abundant hydrocarbons, and maps a route towards future catalytic systems.

It's "easily prepared", eh? Let's take a moment to appreciate the toxic, volatile, pyrophoric nature of this concoction:

"sodium powder, crown ether, trimethylsilyl bromide and N2"

Well, the N2 is probably fine.

The pyrophoric sodium powder might even be a good thing, because it will cause an inferno long before the crown ether has a chance to form explosive peroxides.

Yea, seriously. I love how nonchalant it sounded in the article, too. "They also treated the nitrogen with a silicon compound that allowed the nitrogen to combine with benzene."

I flinched when I got to "silicon" out of force of habit...

The reaction should be conducted in an oxygen-free, pure nitrogen atmosphere where those compounds should be safe to handle.

When it’s boiled to dryness, crown ether can produce peroxides that are unstable enough to explode on their own with shock or additional heat - no oxygen needed.

It’s a not-uncommon mistake to make in a synthetic lab.

My understanding is that evaporating solvent away doesn't form peroxides. Rather, as an ether ages, it can peroxidize. Removing the solvent concentrates the peroxides is all. Sure, it's a little tricky, but they're reporting results of chemistry research, which doesn't mean immediate real world application.

sounds like a classic In The Pipeline "Things I Won't Work With" [0] tale

[0] example: https://blogs.sciencemag.org/pipeline/archives/2010/02/23/th...

Sounds super easy

In a chemistry lab, it's not so tricky.

As far as I understand, the non-nitrogen atoms in the reaction are provided by benzene.

Fun fact: benzene is so important in chemistry that it has two unicode code points, ⌬ and ⏣.

Well, unicode doesn't have much to do with chemistry, or with importance. Those two symbols both long predate unicode (as you'd expect given the nature of unicode).

The reason for the second symbol is that the positioning of the double bonds within the ring is underdetermined (and indeed, doesn't really exist) -- they are in a state of indeterminate flux much like the bonds in a molecule of ozone. The circle explicitly acknowledges that we can't really identify particular bonds as being the double bonds.

>Those two symbols both long predate unicode (as you'd expect given the nature of unicode).

Yes, but notably they are not included in Unicode for compatibility with legacy character sets.

Are they included in Unicode for any reason? They're not textual and don't make any sense (they are actually ill-formed[1]) as independent glyphs.

[1] OK, they're not ill-formed if you really want to insert a miniature icon of a free benzene molecule into running text, but in chemistry you're mostly talking about benzene rings as a structural element in larger molecules, not molecular benzene.

One of the uses of aniline is hypergolic rockets although its pretty toxic stuff and as not used for large rockets anymore. Making test tube rockets with aniline, pretty interesting: https://www.youtube.com/watch?v=OszX18NLtrY

Catalytic nitrogen fixation is one of the holy grails for chemists, so papers that get within spitting distance often get a lot of attention.

This paper seems very interesting, but unless I’m mistaken it’s not catalytic and that’s a big caveat.

Apparently none of the components of the mix get used up except the nitrogen and the benzene. It may be not one-step catalytic, but this should not be a problem.

What am I missing?

Atmospheric nitrogen is a big source of environmental and human harm in the Low Countries. The nitrogen deposits are literally smothering what little nature is left.

It already led to a full-blown crisis in The Netherlands where construction sites were ordered to shut down. In Belgium, with the lack of effective national governance, the nitrogen problem is not being laying dormant.

This kind of innovation hopefully bodes well for Belgium which has both an abundance of nitrogen _and_ a pervasive petrochemical industry.

I think the article is talking about capturing inert N2 from atmosphere directly with benzene, not about nitrogen pollutants like NOx.

Atmospheric nitrogen sounds bad.

And the Netherlands has to contend with some serious dihydrogen monoxide issues, too.

> dihydrogen monoxide

I always wanted to know why this name was picked over "hydrogen hydroxide".

Because people know carbon monoxide is toxic and will quickly make the false association.

People know chlorine is toxic and salt is half chlorine... :/

I'm not sure if you are actually referring to nitrogen?

Nitrogen (N2) constitutes 78% of the air we breathe. It's an inert, nontoxic gas and one of the least hazardous gases around -- the primary hazard being that of asphyxiation in closed spaces at high concentrations (due to displacement of O2).

I'm not sure I follow that Belgium has an abundance of nitrogen. Every country in the world has an abundance of nitrogen - it's literally 78% of the air around us. To extract nitrogen, you pull air into a separation column and out comes N2. Any country in the world can do this. The two inputs are air and electricity (to power the compressor and other equipment).

There is a book which tells the story of fixing nitrogen from air and its a fanatic read:

https://www.goodreads.com/book/show/3269091-the-alchemy-of-a...

its non-fiction

I find it interesting that I initially interpreted the headline “New nitrogen products are in the air” as a story about pollution. I.e., new nitrogen products (pollutants) have been detected in the atmosphere.

I'm sure that was intentional. Effective clickbait.

I saw it more as a pun. Unfortunately given the terrible practice of clickbait we no longer have the inclination to give puns the benefit of doubt.

Ok, we've taken the nitrogen products out of the air in the title above.

Same reaction for me earlier, and I didn’t have the time to look into it and had it on my mind since then. Should the title have “[not about pollutants]”?

Ah well Nitrogen is the most abundant gas in the atmosphere so it's not by any stretch a pollutant.

N2 isn't a pollutant but many nitrogen compounds are major pollutants, and its not so far fetched to call something like NO2 a "nitrogen product"

Nitrous oxides are a by-product of fossil fuel combustion, and are a common and problematic pollutant.

> The discovery comes from a team of Yale chemists who found a way to combine atmospheric nitrogen with benzene to make a chemical compound called aniline, which is a precursor to materials used to make an assortment of synthetic products.

Ok, great. This is stated in a fairly neutral way. But one wonders if we are considering the negative effects of those synthetic products. That was the problem with plastics -- although revolutionary, there was a dearth of discourse about its negative effects, which we are feeling now.

Aniline is already a widely used industrial compound (used to make polyurethane). The novelty here is making it from atmospheric nitrogen.

Nitrogen also makes up 2.6% of the Martian atmosphere and Nitrogen gas will likely be an important feedstock for future Martian ISRU plans.

I'm not gonna lose any sleep over third world farmers realizing better crop yields using newly affordable fertilizer.

It's curious that plants haven't evolved to fix their own nitrogen, given their need for it and its abundance in the atmosphere

They have. Legumes are an important way to fix nitrogen (while simultaneously growing food!).

Why haven't ALL plants evolved to fix nitrogen? It's abundant in the air... and also in the ground. You don't manufacture your own vitamin C, but you could. But there's no need. Humans specifically evolved the inability to do so, where almost all animals can and do.

Symbiotic microorganisms fix nitrogen. Plants don't.

Symbiotic microorganisms digest food. Animals don't.

Wait, that makes no sense.

Symbiotic microorganisms are part of the macroorganism they live in.

Human teeth, saliva and stomach acid do a whole lot more to digest food than beans do to fix nitrogen.

Or do legumes chew the nitrogen before it gets to their roots?

Those products already exist. This is just a new route to them.

Sometimes it's bad to have more routes to something, for example when the end result is plastic.

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