Hydrocarbons Deep Within Earth: New Computational Study Reveals How

Science Daily ^ | 17 Apr 11 | Staff

[thackney]

Crude oil molecules are not polymers.

That is a different molecular structure than that found in naturally occuring crude oil.

[Wonder Warthog]

"Crude oil molecules are not polymers."

But the subject is making long-chain hydrocarbons from methane, not making gasoline from asphalt. Where do you think the term "paraffin" comes from? The very high MW hydrocarbon fractions in crude oil resemble polymers quite closely.

"That is a different molecular structure than that found in naturally occurring crude oil."

I can guarantee you that the molecular structure of any saturated hydrocarbon is precisely the same as polyethylene. The only difference is chain length. And that holds true for both straight-chained and branched-chain hydrocarbons.

[thackney]

Asphaltenes are the same molecular structure as polyethylene?

Alkanes are not polymers. Alkenes are not polymers. Alkynes are not polymers. Cycloalkanes are not polymers. Alkadienes are not polymers.

Some of these can be used to form polymers but they do not exist as polymers in naturally occuring crude oil.

[Wonder Warthog]

"Asphaltenes are the same molecular structure as polyethylene?"

I'm not talking about "asphaltenes". I'm talking about the linear and branched alkanes, above about C20 and on out.

"Alkanes are not polymers. Alkenes are not polymers. Alkynes are not polymers. Cycloalkanes are not polymers. Alkadienes are not polymers.

Reread what I said. The MOLECULAR STRUCTURE of linear and branched alkanes are IDENTICAL to the MOLECULAR STRUCTURE of linear and branced polyethylene. You're arguing chemistry with a chemist. Trust me, I know more about this stuff than you do.

ALL of these compounds have the general form C(n)H(2n+2).

And in actual fact, in polymerization processes there are small quantities of shorter chain species formed that are IDENTICAL to the higher alkanes in crude oil. These are called "waxes", and are an undesirable side reaction to the polymerization process.

"Some of these can be used to form polymers but they do not exist as polymers in naturally occuring crude oil.

And I never said they did. The point I'm trying to get across is that there are mechanisms by which long chains can be synthesized from small molecules. Most of these involve catalysts. Some do not. The point of the article is that a similar "building-up" mechanism is possible naturally.

There's a lot more to hydrocarbon chemistry than just "cracking", whether that be purely thermal or catalytically assisted.

[SunkenCiv]

Thanks Red Badger. This is from a couple of weeks ago, and I think is a duplicate of another recent topic, but I'm pinging it anyway.

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[MetaThought]

I like the term “political peak oil”