MovieChat Forums > Back to the Future Part III (1990) Discussion > Back to the Future 3: Making Gasoline

Back to the Future 3: Making Gasoline

posted 7 years ago by TMC-4
2 replies | jump to latest

NOTE: If you're familiar with the movie, you can skip to the factual question under the ////////s

In the movie Back to the Future III, Marty inadvertently punctures the fuel line, spilling all the Delorean's gas into a bear's cave in September of 1885.

This is the main problem in getting Marty back to the future in this film, since the Delorean must reach 88 mph in order for the flux capacitor/time-circuits to do their thing (they still had a working Mr. Fusion to create the 1.21 gigawatts).

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In the film, they have less than a week to overcome this problem: How to get the Delorean up to 88 mph in a world where gasoline is rare, if non-existent.

Yet, petroleum was around.

How plausible might it have been, for someone with a PhD in chemistry, to obtain enough petroleum and convert it into gasoline so the Delorean can accelerate to the required 88 mph, in the wild west of mid-1885?*

[–] TxMike 7 years ago

Not plausible at all.

If you simply distil crude oil and capture the gasoline fraction it would have a very low octane rating, close to zero. Very nice for Jet fuel but not very good for modern high-compression car engines.

The engine of the DeLorean may be able to actually start on such low-octane fuel but if so it would run very poorly right before it blew itself up from excessing knock.

If Doc Brown had a PhD in Chemistry and if he had studied refining and fuel production, a very long shot at that, he would know that he could use the low-octane fuel along with proper catalysts, high-pressure reaction vessels, and a distillation column to make a small amount of high-octane fuel. He might be able to enlist the help of the local blacksmith to make the hardware but he still would not have a source for the catalysts required for the chemical reactions to convert low-octane saturates into high-octane aromatics and branched alkanes like isooctane.

Yes, I am a Chemist and my career was largely in the fuels business, mostly gasoline and jet fuels.

..*.. TxMike ..*..

[–] TMC-4 (19451) 6 years ago

https://www.quora.com/In-Back-to-the-Future-3-how-plausible-might-it-have-been-to-obtain-enough-petroleum-and-convert-it-into-gasoline-so-the-Delorean-can-accelerate-to-the-required-88-mph-in-the-wild-west-of-mid-1885

Early gasoline was first available in 1863. So by 1885, it could’ve been purchased commercially by Doc Brown. However it was not used widely at that time and it may have required a telegraph order and a wait for the shipment to arrive by train in a few days.

Doc could’ve synthesized his own gasoline by using ordinary heated coal, which would produce coal gas. Coal was widely available in towns across the U.S. in 1885. It would’ve only required a heating chamber, a still/reaction chamber, a catalyst and a great deal of caution to prevent the gasoline from igniting from the flame used during the distillation process. Adjustment of the octane rating could be accomplished by blending the finished gasoline with ordinary petroleum, in order to lower the flash point and flash speed of the mixture.

There are also ways to synthesize gasoline from methanol, which could be obtained by distilling wood byproducts.

While some of these methods weren’t invented by 1885, a scientist from 1985 should be well aware of these things…