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### Topic: Boctane  (Read 39836 times)

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#### Enthalpy

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##### Boctane
« on: August 13, 2011, 02:10:46 PM »
Hello you all!

Boctane is a synthetic rocket fuel designed to improve performance over kerosene.

Finally, I could find it to be bi-cyclobutane C4H7-C4H7, Smiles C1CCC1C2CCC2 (it's not bicyclo[3.3.0]octane aka octahydropentalene)
http://www.freepatentsonline.com/6415596.html
and hand-estimate its heat of formation to +35.4kJ/mol, not far from +55.1kJ/mol claimed there
At +35.4kJ/mol it would bring 4s more specific impulse than kerosene Rp-1 and 7s more than Jp10, combined with a higher density, and might be used by existing rocket stages, fine. As good as Syntin, probably cheaper.

First, would you know more: density, melting point, boiling point, flash point...?

And: how safe and cheap could it be to produce in hundreds of tons?

Thanks!

#### Enthalpy

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##### Re: Boctane
« Reply #8 on: August 22, 2011, 12:01:43 PM »

Is this too difficult?

Or is it too easy for you?

Wrong sub-forum, maybe... But I have no intention to become a chemist, so an answer obvious for everyone else would be fine to me!

#### fledarmus

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##### Re: Boctane
« Reply #9 on: August 22, 2011, 03:55:00 PM »
The only synthesis for spiro[3.3]heptane I have been able to find so far uses methylenecyclobutane for a starting material. Yields are pretty good, at close to ~80%, but the starting material is ~$100/gm and it uses a zirconium catalyst. I don't think it is practical for a multi-ton synthesis. #### Enthalpy • Chemist • Sr. Member • Posts: 3639 • Mole Snacks: +299/-57 ##### Re: Boctane « Reply #10 on: August 22, 2011, 05:55:37 PM » Thank you! Accordingly, Russian rocket builders didn't try to make spiro molecules - though spiroheptane would bring performance indeed. Too expensive even for a very-last stage. Boctane is to be Cyclobutyl-Cyclobutane C4H7-C4H7 (I try to attach a picture), which should be easier to produce. #### orgopete • Chemist • Sr. Member • Posts: 2636 • Mole Snacks: +213/-71 ##### Re: Boctane « Reply #11 on: August 24, 2011, 02:53:29 AM » No answer... Is this too difficult? Or is it too easy for you? Wrong sub-forum, maybe... But I have no intention to become a chemist, so an answer obvious for everyone else would be fine to me! The challenge is the landscape. It is virtually being assumed that the Russians, Europeans, and NASA don't know what they are doing. Don't they know that bicyclobutane is a superior and cheap rocket fuel that can be readily prepared in multi-ton quantities? From my experience, you are far more likely to be successful by utilizing something that has already been shown to work over something that even experts might predict should work but has never been demonstrated to work. Bicyclobutane is apparently a known compound based upon the patent previously cited. That seems a far better starting process than any thought of joining two cyclobutanes. My instinct is that any chemists here would suggest you can forget bicyclobutane as an alternate to kerosene on a cost basis if it is gives only a 2% improvement. However, I could be wrong. How was it prepared? No matter, let's try it based upon hypothetical economics. Let us assume that cyclobutane can be dimerized into bicyclobutane in a single step and in 100% yield. Let us further assume cyclobutane is commercially available in ton quantities at the same price as kerosene. All that is needed is to turn the crank and we're off. The cost to turn the crank on this process is$25/kg. That seems reasonable based upon my experience. If some of the other chemists with industrial experience can suggest another value, that is fine also. We had used a slightly higher value 15 years ago. This is where I got the $25/kg value from. http://greenchem.uoregon.edu/ACSGoingGreenSite/PDFs/20050315TuesPM/1336Cue.pdf My experience tells me you cannot couple cyclobutane, cyclobutane is going to be far more expensive than kerosene, the known route to bicyclobutane is going to be costly in processing steps, and I respect that if Russia gave up on their cyclopropyl rocket fuel when costs had to included in their rocket program, then virtually any other hydrocarbon would have a difficult time to compete with kerosene on a cost per payload basis. If the board were to apply the same standard to this topic, then not being a chemist would never be sufficient for not providing a shred of input. I doubt anyone thought cyclobutane could be dimerized. If cyclobutane is being asked to join together, give at least one other example or principle that would even suggest this to be a reasonable reaction. Once you do that, I think you will find a number of chemists will be happy to help you do a cost estimate from the raw material costs, reagents, reactions, and yields. I faced this challenge working in the agchem industry. If a farmer could buy weed control for$15/acre, then if you had a herbicide that you need to apply 1 lb/acre, you need to be able to make it for $7.50/lb in order to make a profit. That will limit you to very simple compounds. However, if you only needed 0.1 lb/acre, then you could be profitable if you could prepare it for$75/lb. There is no magic to know your compound has to be extremely potent in order to compete on a cost basis. Here, the competition is crude oil. You distill it a couple of times.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

#### Enthalpy

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##### Re: Boctane
« Reply #12 on: August 24, 2011, 07:24:17 AM »
Thanks for the input!

The aim isn't to be cheaper than kerosene, but more efficient. The added payload capacity is quite more than proportional to the fuel performance, and should be compared with launch charges, of which present kerosene costs are nothing.

Syntin, which contained three cyclopropane rings linked to an other, had been used. Excessive cost is suggested by one source without reference. It could just be that two professors knew how to produce it, and when Russia stopped paying their wages, one became a mammoth ivory smuggler and the other a Siberian tiger hunter. Anyway, isn't a string of C3 rings more difficult to produce than of C4?

As Atlas V plans to switch to Boctane, maybe it makes economical sense.

-----

So you consider the C4 ring will break open as soon as we near some halogen?

#### Enthalpy

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##### Re: Boctane
« Reply #13 on: September 01, 2011, 08:30:49 PM »

Heat of formation is +80cal/g (I estimated +77cal/g)
Density 828kg/m3. Viscosity 2.4cPs @+20°C.
Melt -54.5°C / Flash +20°C / Boil +134°C / Autoig +205°C / Decomp +430°C

#### Honclbrif

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##### Re: Boctane
« Reply #14 on: September 01, 2011, 09:50:13 PM »
I'm a chemist and not an economist, but given that we know:

1. The cost of kerosene
2. The cost of the increased payload which boctane will provide

It seems pretty easy to put a definite dollar value on how much boctane can cost and still be economical. Have you run these numbers yet?

Modification:

My reasoning is if you could double your payload with boctane, you could then charge up to double the price for kerosene for it and still count it as an economical fuel. So, can boctane be produced for double the price of kerosene?

Modification 2:

http://www.indexmundi.com/commodities/?commodity=jet-fuel, the cost of jet fuel (which as I understand it is basically kerosene) as of 8/30/2011 was about $1/kg. Assuming orgopete's estimate of$25/kg is reasonable, can boctane provide 25 times the performance?
« Last Edit: September 01, 2011, 10:22:59 PM by Honclbrif »
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