Sciencemadness Discussion Board - Binder issue =(

Binder issue =(

deadpool - 7-12-2015 at 19:09

Hello guys & pyrotechnic gods (or goddess). I have a binder issue. I've read a few post and thought I would give it a try, typically I ended up wasting a lot of product and created a sticky mess. My method was to use polybutene and methylricinoleate (also tried small amounts of oil). I created the methylricinoleate via esterification with methanol and caster oil. My product was a liquid, but once cooled turned into a sold mass. I don't know anything about this product and thought perhaps I made a mistake during the esterification process. I did use sodium hydroxide as the catalyst, which may have been a mistake. Can anyone confirm if this is the right product? Also am I also correct to assume that total inert materials shouldn't exceed 10% by weight? I have extreme difficulty getting 10% plasticizer/binder to mix that well.

DubaiAmateurRocketry - 7-12-2015 at 19:20

Umm, what is the majority of that mass?

deadpool - 7-12-2015 at 19:23

This was the product of the caster oil esterification, guess I should have been more clear on that sorry.

answering my own question, comments are welcome!

deadpool - 7-12-2015 at 19:51

It looks to me like the sodium hydroxide turned the castor oil into a fat

yup.. just googling showed me methyl ricinoleate is a liquid... dang it. Should have I just used an acid for the esterification? Guess I'll try it again.

Deathunter88 - 7-12-2015 at 21:21

Quote: Originally posted by deadpool

It looks to me like the sodium hydroxide turned the castor oil into a fat

yup.. just googling showed me methyl ricinoleate is a liquid... dang it. Should have I just used an acid for the esterification? Guess I'll try it again.

You used sodium hydroxide for an esterification?! No wonder you got such a weird product. Try the same procedure again but this time try using concentrated sulfuric acid instead of the sodium hydroxide.

NitreRat - 8-12-2015 at 00:33

Quote: Originally posted by Deathunter88

Quote: Originally posted by deadpool

It looks to me like the sodium hydroxide turned the castor oil into a fat

yup.. just googling showed me methyl ricinoleate is a liquid... dang it. Should have I just used an acid for the esterification? Guess I'll try it again.

Or better still, use sodium methoxide. Maybe even, the more easily made, magnesium methoxide, but I'm not sure about that one.

Microtek - 8-12-2015 at 01:42

What you have is likely the sodium soap of ricinoleic acid.

I think you should go back one more step; castor oil is a triglyceride, so you could either make a trans-esterification, or you could liberate the ricinoleic acid first (eg. by hydrolysis with hydroxide). Then after purifying the fatty acid you can do the esterification with methanol and sulfuric acid.

[Edited on 8-12-2015 by Microtek]

deadpool - 8-12-2015 at 10:54

Yea i was suppose to mix the methanol and sodium hydroxide to form sodium methoxide first, and I goobered on that part. Thanks guys for the help!

nux vomica - 8-12-2015 at 17:21

When I made some recently I used these ratios.
Mix 50ml castor oil 20ml methanol 0.3 grm potassium hydroxide together , stir and reflux at 100°c for 3 hours use a vertical condenser to stop methanol loss, after 3 hours dilute with h2o and seperate oil layer, dont over agitate oil and water mix or it will take days to seperate because it goes into an emulsion with the water.
Nux.

[Edited on 9-12-2015 by nux vomica]

More questions (feed my brain)

deadpool - 3-1-2016 at 21:12

Hello again,

I was wanting some clarification on the hydrolysis reaction that taking place (this laborious process isn't going to be use so don't flame me, I just want to learn).My current understanding is:

Castor oil is a triglyceride that is mainly comprised of ricinoleic acid. When water is added it the hydroxide anions will attack the triglyceride and break it down (saccharification?) to 3 x ricinoleic acid molecules.

My questions are: Is sodium/potassium hydroxide required or is it just a catalyst? If it is, how do you prevent the soapy salt forming? Lets assume that I wanted a high quality product and used the method provided by Microtek. From what I understand from this process I should mix castor oil & water (perhaps with hydroxide salt) and setup for fractional distillation to yield pure ricinoleic acid in receiving glass.

NeonPulse - 4-1-2016 at 18:11

The hydroxide is the catalyst, and by using only a tiny amount and keeping the temp fairly low 20-25c and you should be able to avoid the saponification of the oil. I'm not sure about distilling the oil though. In my experience just washing the oil with a little water to remove methanol any excess catalyst and glycerol formed is sufficient. By putting the product into a measuring cylinder and letting water run through this works for me while preventing too much loss if an emulsion formed with the water. Further methanol can just be warmed off and the oil dried over a dessicant if needed. The end result was the nice clear Kind of thin oil suitable for plastics.