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Do chemical reactions change when you charge the entire reaction vessel plus or minus $\pu{1 MV}$ or more? Is there a name for such chemistry?

I was looking at "electrochemistry" expecting to see a host of information on charged reactions (either statically or with a constant charge applied) but it all just appears to be focused on batteries, not so much on synthesizing novel materials.

aventurin
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CoryG
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    So what you want more precisely is high electric fields (V/m). This has some interesting facets. It is possible to generate massive fields (> 1 MV/m) by submitting a thin sample sandwiched between two electrodes to a very mundane single-digit voltage difference. Also, the kinds of electric fields which build up on the interface between electrodes and solvents (electric double layer may be relevant. I don't know much about these things, though. – Nicolau Saker Neto Oct 16 '17 at 10:23
  • It is also worth noting that a static electric charge on the outside of a vessel will make no difference to the electric field gradient inside the vessel. If you wanted to explore an effect, you need to create a field gradient and that means two electrodes at different potentials. – matt_black Oct 18 '17 at 19:34

5 Answers5

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Long story short, no, they don't.

Charging a vessel to 1 MV is not a big deal, if you look at it from the inside. To put things into perspective, imagine a vessel of about 10 cm across, which is kinda OK for a flask. Imagine it spherical to make the calculations easier.

  • Now, the capacitance of a sphere is $C=4\pi\varepsilon_0R$, which evaluates to 5.56 pF (yes, "p" stands for "pico").
  • So charging your vessel to 1 MV implies putting $5.56\;\mu\rm C$ of electric charge on it.
  • That's $3.48\cdot10^{13}$ extra electrons (or some negative or positive ions, that doesn't matter) ...
  • ... which may seem big until you compare it to the amount of water that would fit into the vessel: $1.75\cdot10^{25}$ molecules.

So it is like 1 electron per quite a few billions of molecules. That would not make much of an influence. The molecules will just sit there as usual, feeling nothing; most of them have never seen an electron in their entire lives, and have no idea that their vessel is being charged.

Things will change a great deal if you touch the vessel from the outside, but that's just ordinary electrochemistry which you seem to put out of scope of your question.

Ivan Neretin
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    Plus the charge will tend to accumulate on the outside of the vessel, not internally, if I remember my E&M correctly. – JAB Oct 16 '17 at 15:09
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    Yes, that too. Moreover, for the same reason of repulsion, they will tend to leave the vessel and fly away. – Ivan Neretin Oct 16 '17 at 15:21
  • What about with a much smaller reaction vessel - something on the order of a capillary tube. – CoryG Oct 16 '17 at 17:07
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    @CoryG if the container is open, you could do things like electrospraying. The drastically increased surface area it provides could change rates and such, but electrospraying megadalton-sized molecules (proteins) is surprisingly gentile to them. – Nick T Oct 16 '17 at 18:33
  • Cannot one in principle think of the reaction between two opposite charged walls? Like a dielectric layer. Whatever has electrical dipole align with the field and possibly this hinder the reaction (or affect the reaction). Plus effect like inhomogeneous concentration. Never thought of this. – Alchimista Oct 17 '17 at 12:22
  • @Alchimista You've just described an electrolytic cell. Such a thing surely does exist, and gives rise to an entire field of chemistry. – Ivan Neretin Oct 17 '17 at 12:27
  • @Ivan Neretin. I mean whatever you do in apolar solvent without ionic content. I thought it is implicit. – Alchimista Oct 17 '17 at 12:30
  • I said walls else I would have called them electrodes – Alchimista Oct 17 '17 at 12:31
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    @Alchimista When you apply voltage to the walls, they become electrodes, or at least try to. If that can't be done, they hardly influence anything. It is not that easy to align the dipoles. Related: https://chemistry.stackexchange.com/questions/60289/in-practice-do-polar-molecules-actually-align-in-an-electric-field/60297#60297 – Ivan Neretin Oct 17 '17 at 12:52
  • @Ivan Neretin I know this. I said in principle. You can think of a very strong field and I wounder if it could affect the reaction. For instance the kinetics. Statistically colliding molecules will have an orientation different that that without field. Assuming most of mechanisms, the reaction should slow down. It is now clearer? I am not thinking of getting totally different chemistry but some kinetical effects, and perhaps different "selectivity" if more than one product is expected. And again in principle. Surely we will never get perfectly aligned molecules, and more so in a liquid env... – Alchimista Oct 17 '17 at 13:02
  • @Alchimista OK, then I'll repeat the obvious for the benefit of others: yes, the alignment of molecules could theoretically result in some unusual chemistry, but it is impossible, because the required fields are too great and would cause a breakdown. – Ivan Neretin Oct 17 '17 at 13:27
  • This is far from repeating the obvious because 1) you did not even mentioned it in the previous comment and 2) there is nothing too great here.* The breakdown will be chemistry, and indeed a radical change :) No, I wasn't considering field able to strip apart a molecule. But you suggest an even drastic chemistry. Cheers. *tilting a dipole will hardly exceed splitting two charges – Alchimista Oct 17 '17 at 13:32
  • Well, I explained this in an earlier answer elsewhere, see the link in one of my comments. – Ivan Neretin Oct 17 '17 at 13:44
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    Also worth noting that a vessel with a large charge will still have a zero electric field gradient on the inside. So there will be no field for the molecules to feel. – matt_black Oct 18 '17 at 19:36
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If the static charge on your "reaction vessel" is as high as 1MV (megavolt), you may find that parts of your lab that you wouldn't otherwise consider to be your reaction vessel start to take part in the reaction.

If we suppose that your reaction vessel is made of "window glass", the dielectric strength is only about 10MV/m, and assuming that your vessel is the thickness of conventional glassware, a static discharge through your vessel is not out of the question. Such an event will definitely change the "chemistry" of your experiment significantly, as lightning bolts often do.

As far as terminology goes, I'm not sure if there's a name for the sub-discipline of chemistry dealing with chemical changes under high electric field strengths, but electrochemistry might still be pretty close to what you are looking for. Note that the field strengths typical in electrochemistry are usually on a much smaller scale than what you describe.

guenthmonstr
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I really like Ivan's answer above, but wanted to add one other perspective.

Static discharge is a significant possibility, and that might change the chemistry (e.g., redox events). If that doesn't happen, I'd argue that very little will happen because these fields are very common on the nanoscale.

Let's imagine we have ~1MV/m applied to the vessel. That works out to $1\times 10^6\; \mathrm{V/m}$. So about 1V per µm. Even if you have a much smaller reaction flask (10 cm maybe), that's 1V per 100 nm.

Consider the molecular scale. If I have a monocation separated 1.0 nm from a molecule, the molecule experiences ~1V/nm in vacuum. That would be $1\times 10^9\; \mathrm{V/m}$. Granted, in any reasonable environment, the dielectric constant of the solvent will decrease the field substantially, but even in water, the field would be ~$1\times 10^7\; \mathrm{V/m}$.

There's an atomic unit of electric field: $5.142 \times 10^{11}\; \mathrm{V/m}$. That corresponds to the interaction energy between a proton and an electron in a hydrogen atom.

Your fields are much lower than common ion-molecule interaction fields or proton-electron fields.

Geoff Hutchison
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  • I'll point out that you can get interesting interactions (polarization, induced dipole, molecular rotation/alignment, even electromechanical effects) at much lower voltages. – Geoff Hutchison Oct 18 '17 at 18:26
  • I'm wondering if the static discharge can effectively "steal" energy from a reaction and halting it or lowering yield. I'm thinking of a situation that would parallel this -- maybe sort of like discharging a capacitor or something if that makes sense. – Melanie Shebel Oct 18 '17 at 21:07
  • I heard that strength of molecular field was even used to test Standard Model, IIRC. – Mithoron Oct 18 '17 at 21:53
  • If you had 1MV on a capillary tube wouldn't that cause all the polar molecules to align radially though? That seems to influence proteins-driven pretty radically when you have hydrophobic portions of the molecule on the inside and hydrophobic portions on the outside. I can't claim to have experimented with it or read of any experiments with it, but wouldn't that alignment via electronegativity have a pretty radical effect on any polymers? – CoryG Oct 19 '17 at 15:17
  • @CoryG - I'd have to do some calculations, but electrochemistry demonstrates that screening occurs pretty rapidly. See, e.g. https://en.wikipedia.org/wiki/Double_layer_(surface_science) – Geoff Hutchison Oct 20 '17 at 00:39
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High electric fields can indeed influence chemistry.

E.g. the First Wien Effect describes how high electric fields ($10^7~ \pu{V~m^{-1}}$) increase the conductivity of electrolytes.

The Second Wien Effect can lead to an increased dissociation of weak electrolytes. There's some speculation that this non-linear effect may play a role in the conduction of electrical impulses in neurons where strong electric field exist at the membrane.

aventurin
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I thought about this too but knew it will work only in space so that the different charges would not be involved into a developing field. If you study idle or colder gasses, they show that negative ions become more stable because of lesser collisions. And the same for positive ions but that is kind of obvious even with collisions. I find this challenging opportunities when studying elektrochemistry (and it's influence of temperature differences which are also more easy to install in space). Think of all molecules sharing electron; one could think of a shortage that could become quite different in space if we could add or diminish charge in processes. My interest has come from discovering the non-existence of electrical repelling. When millions of volts can be stable just being enough isolated; then how could one say that electrons are repelled when charging such spheres??? Eric Dollard proposes the same in his youtube story: the history of energy synthesis (47th minute). Repelling is a postulate and never investigated. The definition of an electrical field is OK but repelling is being "explained" outside this definition. Make two big plates (1 m2) charged equal and have a probe charge in between them (equal charged) and nothing will happen (untill you approach the borders of the plates when charges outside of the plates get their influence. The electrometer is a fraud since the quality of our earth to attract any kind of different charge is being perfected by the earthed shielding and so explains the attracting forces on the blades. Fieldlines don't go to likewise charged items because there is no voltage difference and so no attraction and this last argument is the one from Eric Dollard and his website. If people only would understand this extremely dumm and simple mistake it could revolutionize electrochemistry perspectives for our future. Also get aware of the fact that all elements are elektro negative, meaning they attract electrons (there is no such quality as "electro positiveness!!). This together with the fact that it costs at least around 13 ev to loosen an electron out of it's bonded state and the notion that our earth would be on zero is a total misrepresentation of the truth !!!!

Kees de Vos
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    This is very convoluted and extremely confusing. Can you break it up into paragraphs and substantiate your claims via mainstream references, please? – jonsca Oct 17 '17 at 23:05
  • The problem is that it is very contrarian against main knowledge, so one should check this out. My "problem" is that I never did the official courses in chemistry or physics because of this huge misconception of repelling forces which is the beginning of both these mentioned sciences. Boy have I been right on this! Have a look on the site of Miles Mathis where he corrects numerous other mistakes. Mistakes I guessed to exist from off the beginning. I apologize for my style of cramming important facts and considerations; please ask what is wrong about them. – Kees de Vos Oct 19 '17 at 08:40
  • Mainstream references are important for answers on the site. Even if there were to be some truth to your claims, it's important for students to learn the fundamentals first. – jonsca Oct 19 '17 at 23:05
  • Jonsca, I fully understand and appreciate your attitude and I did mention Eric Dollard who had a lot of views on his enormous body of work on the history of electricity, but I cannot help that no one started thinking about his sole remark on that 47th minuit and I'm trying since almost 50 years. Everyone is stuck on mainstream knowledge and math can "correct" evils in understanding such that people lose track. As long as formula's make sence no one doubts the axioms. Have like 20 barmagnets organise themselves and repelling disappears. Counterintuitive but not to be found in scholarly books – Kees de Vos Oct 21 '17 at 07:12