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I am creating a carbon planet with seas of methanol on its surface, but I am not sure that this is possible.

It is predicted that carbon planets are depleted of water, since the available oxygen would be depleted by reacting with carbon to mainly form simple compounds such as carbon monoxide, carbon dioxide or carbonate ion. But would something similar happen with low molecular weight alcohols, such as methanol?

According to this work, methanol is formed in molecular clouds mainly in dust grains through the successive hydrogenation of carbon monoxide. And it is destroyed by reacting with the hydronium ion, one of the most abundant ions, produced from water.

I think that, due to the greater amount of carbon available and, therefore, of carbon monoxide, methanol would be more abundant in the medium and due to less amount of water, it would be less prone to dissociation. Considering this, it would be logical to think that a carbon planet with seas of methanol on its surface be possible.

But I am not an expert on this and I have not found papers on it, so I would like to hear suggestions. Is it possible a world like this or could methanol also end up like water?

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  • $\begingroup$ It's an interesting question as to whether carbon planets actually exist in the first place, even before you get to the question of what kind of oceans they can have! $\endgroup$ – mistertribs Aug 16 at 19:03
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Interstellar methanol clouds!

I read up on methanol, I was surprised to learn that methanol is one of the most common molecules in interstellar space!

https://web.archive.org/web/20110720152236/http://www.jodrellbank.manchester.ac.uk/news/2006/cloud/

Upgraded MERLIN spies cloud of alcohol spanning 288 billion miles

Astronomers based at Jodrell Bank Observatory have discovered a giant bridge of methyl alcohol, spanning approximately 288 billion miles, wrapped around a stellar nursery. The gas cloud could help our understanding of how the most massive stars in our galaxy are formed.

Where is it coming from? Apparently methanol formation in space is different from what happens in gaseous environments, and comes from hydrogen reduction of carbon monoxide.

https://www.researchgate.net/publication/248627944_Observational_constraints_on_the_formation_of_interstellar_methanol

The absence of13C depletion as compared to CO2ices pointsto a methanol formation from cold CO, possibly via hydrogenation of CO on grains... In addition, while the hot core componentshows a CH3OH/H2O gas-phase ratio similar to that in ice, this ratio is 60 times higherin the compact ridge component. This increase is accompanied by a decrease in thewater abundance, suggesting that water here is consumed in the formation of methanol in accordance with formation from mixed H2O/CH4ice.

Space is different! Back to the question: I can imagine that a rocky planet or a carbon planet in the vicinity of a colossal cloud of methanol might accumulate an environment largely made of this methanol, which then might condense into lakes according to pressure and temperature conditions. In fact, condensation of a methanol cloud like this might be your mechanism for building the carbon planet in the first place.

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I noticed you had a question about whether a carbon planet was possible earlier also. I don't remember the answer given, but what you're looking for is effectively a hydrocarbon cycle. For more real-world research on this matter, look up the moon Titan in our solar system - it's the only moon we know of with an atmosphere, and it has rivers and seas of hydrocarbons!

More specific to your question, keep in mind what conditions are needed not only for methanol to rain from the sky, but for it to exist in liquid form at all. In short, you need high pressure and low temperatures. On earth, pressure at sea level does increase when it rains, but not by THAT much - you probably don't feel like weak in the knees to the point of collapse when a slight drizzle breaks out. On this planet though, you might. It also often gets colder when it rains (see: Indian monsoons). Here, it either already was freezing (I'm assuming so at least in the regions where there are seas) or it becomes even colder than its already low temperatures when it rains. So how cold is this? Under our atmospheric conditions, methanol turns solid at -97.6 C and starts boiling at 67.2 C. To do some of your Titanic research for you: the average temperature on Titan is -179 C. Periodically though, it does seem to drizzle a little bit of methane, and there do seem to be seas on Titan made of liquid hydrocarbons.

So what weather effects cause such dramatic changes in temperature and pressure? Feel free to copy off of Titan. Otherwise, consider something I just made up: upper-atmosphere tornadoes. These tornadoes would not necessarily touch the ground, but contribute to the necessary pressure difference and temperature drop needed to support periodic rain. Long-lasting, sustained batches of these tornadoes could sustain seas underneath. I hope this is useful!

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It depends on what molecules are most stable/lowest energy in given environment. I am not a chemist, so can't say for sure, but methanol probably isn't, see Wikipedia:

It does not persist in either aerobic (oxygen-present) or anaerobic (oxygen-absent) environments. The half-life for methanol in groundwater is just one to seven days, while many common gasoline components have half-lives in the hundreds of days (such as benzene at 10–730 days).

Granted this is due to biological activity, but it indicates methanol is easy to react with overall.

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    $\begingroup$ That's right. Methanol degrades rapidly in the environment, but this is mainly due to the influence of microorganisms that use it as a growth substrate (biodegradation), but we are theorizing about a lifeless environment. In addition, methanol is the most stable alcohol: it does not decompose easily in an acidic medium at high temperatures. $\endgroup$ – URIZEN Aug 16 at 21:48

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