Hypothesis:

Is 30% the correct amount to force the transesterfication reaction to completion with ethanol?

Or is a higher amount required?

Test conditions:

1 liter of new canola oil.

9g of KOH

300ml of pure ethanol.

I"ll have to get some pure ethanol from my methanol supplier here next week to try this out.

But my hunch is that it's going to take about 35% ethanol to keep the reaction from folding back on itself.

I'll post the results as soon as I can get some ethanol here, probably next week.

Spencnaz,

Since ethanol has a Molar mass of 46.06844(232) g/mol and methanol has a Molar mass of 32.04 g/mol you would need to use 1.44 times as much et as me to get the same molar concentration. So, 30% would be equivalent to 20.83% if the purity was the same between the 2. 31.7% would be more like it if you wanted to get to the same concentration as 22% methanol.

I can only help with the math though. Let me know what seems to work. The reaction could be different if other ways.

Yeah, that's what bothers me sometimes. The math will tell you one thing and then the actual results can be much higher or lower than that.

There can be a very discernible amount of uncertainty, especially when using WVO.

While it isn't "pure" ethanol, since I use E85 as a source of cheap anhydrous ethanol (So long as you use it the day you buy it, helps having an E85 pump fifteen minutes away), I haven't had any problems on a "lab" level with just the normal 22%.

This is, of course, adjusted for the 15% gasoline content of the liquid. 220mL/L adjusted for 85% purity results in needing 258.82mL of 85% purity alcohol to result in an actual 22% v/v ethanol content. I typically round up to a simple 260mL/L, giving me 22.1% v/v ethanol content.

So far, with either new or used (oil typically titrates under 2 for NaOH), I haven't managed to have a truly hard to wash liter or half liter batch, and the one emulsion produced during washing cleared itself overnight (used oil, titrating @ 2.1 NaOH). Typically it only takes two or three washes for the resultant product to produce clear wash water and dry easily.

There is some difficulty in dissolving the sodium hydroxide in the E85, solved by putting it in a sealed jar and letting it sit, occasionally walking by and shaking it up, or letting it sit overnight. I haven't tried KOH yet, not having a ready source or supply.

And you're not worried about the 15% gasoline that's in there?

By the end of that third wash, I can't smell it any more when I open up the jar. And since the smell of gasoline lingers long after any measurable quantity is gone, I figure it's either a trace amount remaining or it's not there at all. [edit]This is also why I'm interested in the distillation utilized in the GL style process, as that should cut down on the washes needed to fully remove the gasoline content. Recovered ethanol/gasoline would just go straight into the CIS-powered wagon, rather than trying to recover ethanol from that mixture.[/edit]

I probably should also have noted that I shake that test jar for a long time on an intermittent basis: shake five minutes, let it sit for five minutes. Shake five, sit five, cycle repeat for an hour. I'm probably doing the same basic principle as the people who are trying to go as low as they can with methanol.

And the gasoline chain in there isn't acting as a reaction inhibitor?

Not that I can tell. I don't think gasoline or any of its components are reactive with hydroxide, oil or alcohol, so it's in my view a bit like any particulates left in the oil: an uninvolved bystander just along for the ride through the pump and mixers.

Not being a chemist, organic or otherwise, I can't really say for sure that it's not doing anything. I can say I haven't really had many problems with separation, though that's probably more related to the use of "low" concentrations of ethanol than the gasoline. Just let the jar sit for an hour or two, overnight is better, and I have a nice glycerine-coloured layer down on the bottom of the jar.

How much catalyst are you using as a base amount?

I have found in the past that really badly converted biodiesel doesn't always emulsify in the wash, so if yours was REALLY off, maybe that wouldn't show up as an emulsion.

However, another possibility just suggested itself. I'm putting it into the 'how much ethanol' thread.

Would this reaction only fully complete then with reagent grade ethanol? That could prove even more spendy than the current methanol prices.

quote:

Originally posted by girl mark:
How much catalyst are you using as a base amount?

I've been running with a base NaOH quantity of seven grams.

I figure I'm getting at least some reaction, as I do get dropout after a not unreasonable (fast or slow) length of time.

Brand new in this forum.. and with this subject. I have some test using Méthanol - éthanol, NaOH - KOH and different mixing process.... and I have found out that all the test with ethanol are out, and the methanol work properly (glycerol different using NaOH and KOH, but fuel OK).
I need to product with éthanol (supply reason), any tips to help me understanding and solving this.
cheers

Nothing is lost, nothing is created, all is transformed

Read through past posts on this same section of the forum, folks are sucessfully using E85 methanol and have developed techniques (adding water mostly) to pretty much insure seperation.