Tag: chemistry

Mechanochemistry

This sounds very promising, both for refinery purposes as well as gas storage. Still not convinced that hydrogen is a good fuel though.

The team found a super-efficient way to mechanochemically trap and hold gases in powders, with potentially enormous and wide-ranging industrial implications. Mechanochemistry is a relatively recently coined term, referring to chemical reactions that are triggered by mechanical forces as opposed to heat, light, or electric potential differences. In this case, the mechanical force is supplied by ball milling – a low-energy grinding process in which a cylinder containing steel balls is rotated such that the balls roll up the side, then drop back down again, crushing and rolling over the material inside. This process could separate hydrocarbon gases out from crude oil using less than 10% of the energy that’s needed today. Distillation is responsible for 15% of global energy use.

The gas separation use case would be a pretty huge advance all by itself, but by storing gas securely in powders, the team believes it’s also unlocked a compelling way to store and transport hydrogen, which could play a key role in the coming clean energy transition. The powder can store a hydrogen weight percentage of 6.5%, which is 2x the current record.

2D Polymers

Using a novel polymerization process, MIT chemical engineers have created a new material that is stronger than steel and as light as plastic, and can be easily manufactured in large quantities. The new material is a 2D polymer that self-assembles into sheets, unlike all other polymers, which form 1D, spaghetti-like chains. Until now, scientists had believed it was impossible to induce polymers to form 2D sheets. Such a material could be used as a lightweight, durable coating for car parts or cell phones, or as a building material for bridges or other structures. “We don’t usually think of plastics as being something that you could use to support a building, but with this material, you can enable new things. It has very unusual properties and we’re very excited about that.” The new material’s elastic modulus — a measure of how much force it takes to deform a material — is 4-6x greater than that of bulletproof glass. Its yield strength, or how much force it takes to break the material, is 2x that of steel, even though the material has 15% the density of steel. An important aspect of these new polymers is that they are readily processable in solution, which will facilitate numerous new applications where high strength to weight ratio is important, such as new composite or diffusion barrier materials. Another key feature of 2DPA-1 is that it is impermeable to gases. While other polymers are made from coiled chains with gaps that allow gases to seep through, the new material is made from monomers that lock together like LEGOs, and molecules cannot get between them. “This could allow us to create ultrathin coatings that can completely prevent water or gases from getting through. This kind of barrier coating could be used to protect metal in cars and other vehicles, or steel structures.”

Unclear if more plastic use is helpful, but if the alternative is more concrete, that’s not great either. And if we’re extra lucky, it helps to prevent corrosion at scale, which would give all structures a much longer lifetime.

Multi Density Water

Water, the most commonplace of liquids, is also the strangest. It has at least 66 properties that differ from most liquids – high surface tension, high heat capacity, high melting and boiling points and low compressibility. 1 school of thought is that water is not a complicated liquid but ‘2 simple liquids with a complicated relationship’. For some, this statement contradicts the basic principles of physical chemistry; for others it explains just why water behaves in such an anomalous way. Researchers have been searching for this putative liquid–liquid phase transition ever since, and evidence has slowly accumulated that it really exists. New experiments now supply what seems to be a direct observation of such a transformation between liquid states of different density – not in pure water but in solutions of the sugar trehalose. Understanding how such supercold solutions behave could have implications for biology and cryopreservation – where damage to biological tissues by ice crystals must be avoided – as well as for the water-rich states that might exist in the atmospheres of gas giants. Liquids are structurally disordered, so it’s not immediately obvious how they can support 2 distinct structures with different densities. But that does seem to be possible for liquids in which some degree of directional bonding, such as hydrogen bonds between adjacent water molecules, makes distinct local structures possible.

Small Molecule Medicine

Unless you are old or chronically sick, it’s likely that the only drug you’ve ever taken that hasn’t been a small molecule is a vaccine. Indeed, drugs that aren’t small molecules are so strange and rare we usually don’t think of them as “drugs” but as a separate entity: vaccines, monoclonal antibodies, anabolic steroids.

But, like, the vast majority of molecules found in our body, and in all of organic life, are not classified as “small”. And the vast majority of the things doing something interesting are not really molecules, but more so fuzzy complexes of molecules (ribosomes, lysosomes, lipoproteins, membranes).

So why are virtually all drugs small molecules? Prima facie we’d expect most of them to be complexes made up of 10s to 1000s of very large molecules.

The answer lies in several things:

  • Easy to mass-produce
  • Simple to administer
  • Cheap to store
  • Homogenous in effect
  • Quick to act

Medicine is slowly undergoing the process of learning how to work with complex molecules. In parallel with normal medicine, I’d like to think that biohackers with the ability to custom order whatever they can dream of, will lead the way with self-experimentation. Figuring out the limits and benefits from individualized design and continuous monitoring. For now, this is mainly click-bait, people injecting a bioluminescence gene with CRISPR kinda stuff, but some of it isn’t. As an example, the guy from ThoughtEmporium self-designed a therapy to get rid of lactose intolerance (though the solution is not permanent, it lasts for a few months). 100s of other such people are engaging in similar experiments, and the more people do it, the more resources become available, the easier it will get, and the better the ROI. As this happens, social acceptance will follow and pharmaceutical companies will get more on the deal.

Haber-Bosch

50% of the nitrogen in our bodies came from the Haber–Bosch process. It’s in every protein and every strand of DNA. Ponder that — “50% of the nitrogen in your blood, your skin and hair, your proteins and DNA, is synthetic.” The Haber-Bosch process catalyzes the production of ammonia (NH3) from N2 and H2 gas. We need “fixed nitrogen”, available to our organic chemistries as atomic nitrogen. It is the limiting factor for the growth of all food. While nitrogen gas is about 80% of our atmosphere, not one atom of it is available for our use when tightly bound by the triple bond of N2 gas, the strongest chemical bond in nature. It is sequestered all around us. In nature, N2 is liberated to atomic nitrogen in small amounts by lightning strikes (it needs 1000°C) and slowly by nitrogen-fixing bacteria in the soil. Hager argues that if we reverted to relying on just those natural sources, 3b people would die of starvation in short order — our soils simply could not produce enough food for the mouths now on Earth. The Haber process consumes 4% of the world’s natural-gas production and 1.5% of the world’s energy supply.

2021-11-30: There’s a potential replacement:

The process is as clean as the electricity used to power it, and produces around 53 nanomoles of ammonia per second, at Faradaic efficiencies around 69%. The highest reported previous efficiencies for ammonia electrolysis sat around 60%, with the exception of 1 other lithium cycling approach that managed 88%, but required high temperatures of 450 °C. The team says it’s massively scalable, capable of operating either at industrial scale, or in extremely small on-site operations. “They can be as small as a thick iPad, and that could make a small amount of ammonia continuously to run a commercial greenhouse or hydroponics setup, for example.” This kind of distributed production model, as we explored looking at FuelPositive’s modular, container-sized ammonia production units, would have additional benefits in that it would eliminate the distribution and transport that contribute significantly to the financial and emissions costs of the current ammonia model.

2022-05-04: What happens when you think you can do without Haber-Bosch.
2022-07-22: The same team was able to improve ammonia electrolysis further, with 3x yield and nearly 100% energy efficiency.

We investigate the role of the electrolyte in this reaction and present a high-efficiency, robust process enabled by compact ionic layering in the electrode-electrolyte interfacial region. The interface is generated by a high-concentration imide-based lithium salt electrolyte, enabling stabilized ammonia yield rates of 150±20 nmol s-1 cm-2 and current-to-ammonia efficiency closely approaching 100%.

First New Blue in 200 years

for the first time in 2 centuries, a new shade of the celebrated color is available for artists — YInMn Blue. It’s named after its components — Yttrium, Indium, and Manganese — and its luminous, vivid pigment never fades, even if mixed with oil and water. Blue pigments, which date back 6000 years, have been traditionally toxic and prone to fading. That’s no longer the case with YInMn, which reflects heat and absorbs UV radiation, making it cooler and more durable than pigments like cobalt blue.

Medicinal chemists uplevel

Are medicinal chemists taking it too easy?

In medicinal chemistry, we have now reached a state where millions of building blocks have previously been engineered and can now be used in molecular design and synthesis. In addition to the increase in the number of new amines, boronic acids have been another fast-expanding reagent class since the introduction of the Suzuki coupling method. And if we can get our work done via such easy reactions – plenty of experience in doing the reactions, relatively easy purifications, existing scaleup expertise, and so on – then why shouldn’t we?

Automated Discovery

To what extent can scientific discovery be automated? Where are the areas where automation can make the biggest contribution to human efforts? These questions and a number of others are addressed in a very interesting 2-part review article on “Automated Discovery in the Chemical Sciences”. As the authors say, “The prospect of a robotic scientist has long been an object of curiosity, optimism, skepticism, and job-loss fear, depending on who is asked” I know that when I’ve written about such topics here, the comments and emails I receive cover all those viewpoints and more. Most of us are fine with having automated help for the “grunt work” of research – the autosamplers, image-processing and data-analysis software, the plate handlers and assay readers, etc. But the 2 things that really seem to set off uneasiness are (1) the idea that the output such machinery might be usefully fed into software that can then reach its own conclusions about the experimental outcomes, and (2) the enablement of discovery through “rapid random” mechanized experimental setups, which (to judge from the comments I’ve gotten) is regarded by a number of people as a lazy or even dishonorable way to do science.

RNA-DNA chimeras

Origin-of-Life Study Points to Chemical Chimeras, Not RNA

research is beginning to show that starting with the right kind of mess is not only more realistic, but more effective at generating the materials vital to life, while also doing away with problems that have plagued purer systems. “There are times when we have mixtures, rather than just the isolated reactants that people typically use, and we get better results”. When mixtures are taken into consideration, the emergence of life on Earth in some ways “is not as hard as we might think it is.” What if the chimeric instability was, instead, secretly beneficial and offered a more natural way to get to a world of pure RNA and pure DNA right out of the gate?

Because the nucleic acids with mixed backbones formed weaker 2-strand systems, they didn’t succumb to the strand separation problem that prevented replication for pure RNA. Moreover, during their replication process, the RNA-DNA chimeras preferentially synthesized strands of pure RNA and pure DNA rather than new chimeric molecules — and they produced more of those pure compounds than pure nucleic acid templates did.