Hydrocarbon Gelling Agent
A highly accessible method of manufacturing a hydrocarbon fuel gelling agent
Background/Motivation
I built a prototype flamethrower with mediocre results. In order to improve the range and burn time of my flamethrower, I wanted to decrease turbulent flow of the fuel inside the fuel lines (promote laminar flow) and have a sort of neutral "filler" so that the fuel does not burn too fast. A fuel gelatinizer is an excellent way of doing this. The typical approach that amateurs will do is to simply use polystyrene, which produces a terrible, non-fluid gunk. The compound I present here creates a homogeneous mixture with controllable viscosity depending on the w/v% when incorporating the powder into fuel.
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Note: This compound is intended for research only. Do not use this for any other purpose. Please credit me and the patent authors if you decide to use this synthesis in your research!
Design Process
I began researching a well known fuel thickener, napalm to get some ideas for a compound that I can synthesize that's accessible to me. I came across a patent describing a fuel thickener consisting of aluminum soaps (aluminum salts of carboxylic acids). Several other patents used a mixture of other fatty acids (namely 2-ethylhexanoic acid). I attempted to get a hold of 2-ethylhexanoic acid through some chemistry suppliers to no avail. However, the general idea that a good fuel thickener is an aluminum salt of carboxylic acids is all I needed.
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Using what I gathered and an additional patent outlining a good procedure of producing an aluminum soap, I created a procedure that I can follow in my home lab. Unfortunately, oleic acid was the only suitable carboxylic acid that I could get a hold of through eBay.
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Through numerous trials, I have found that the addition of carrier particles (diatomaceous earth) is necessary for uniform gelling of fuel and for a very fine powder. These trials have also shown that finer powders are far more effective in gelling gasoline.
Procedure
Synthesis Instructions
1. Add a melted mixture of 50g oleic acid (or 25g oleic acid and 25g coconut oil fatty acids (napthenic, palmitic, ...) if available) to a 1000mL aqueous solution containing 37g sodium hydroxide. Addition of more sodium hydroxide may be necessary to have complete saponification. Stir until solution is opaque or thoroughly mixed.
2. Heat solution to 66 C and stir for 10 minutes
3. Add in 5g of activated carbon and continue stirring for 5 minutes
4. Filter the solution and cool the filtrate to room temperature
5. Add 10 grams of diatomaceous earth to the cooled filtrate
6. Dissolve 37 grams of aluminum sulfate (decaocta hydrate) in 100mL of water and slowly add to the filtrate solution. A white precipitate will form.
7. Filter the precipitate and add to a beaker containing 5 grams of diatomaceous earth and water. Stir and then filter the precipitate again.
8. Dry the precipitate in an oven at 50 C or air dry until moisture is no longer present. The dried product should be a uniform and fine powder when broken up
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Gelling Instructions
1. Take napalm mix and add ~25% by weight to a beaker containing gasoline. Stir until napalm is fully dissolved. Add more napalm mix if desired consistency is not obtained.
2. If napalm is not fully dissolved, heat the solution at 60 C and stir vigorously until desired consistency is obtained. Remove from heat if evaporation is excessive.
Resulting Compund
30% by Mass Combustion Test
Future Designs
I hope to get access to other carboxylic acids to test in the future
Materials
- Aluminum Sulfate
- Oleic Acid or other long carboxylic acids
- Sodium Hydroxide
- DI Water
- Activated Carbon
- Diatomaceous Earth