New Methods #2. The Imisides Method

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

geewizztoo; 56.11 grams KOH in dry methanol produces about 18.015 grams of water, plus potassium methoxide

Thanks Wesley, now I get it, its just the ratio of molecular weights (sorry, I'm no chemist).
With the molecular weight of CaO, coincidentally being the same as KOH (56), I understand now why Dr Mark said that the dosage of CaO is 1:1 with the amount of KOH used.

From an economic standpoint, the price of CaO is roughly the same as KOH, so this would add a bit of extra expense. I'll have to try it out and see if the benefits are worth the extra cost and effort to settle the sludge out of the methoxide mixture. I can see why Dr Mark had second thoughts about this process having commercial value.

CaO will certainly react with FFAs (CaO is basic, and bases love to react with acids). Can't tell you the chemical equation though!

Thanks Andy

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

Just thought of another question:
Does some of the KOH dissolve in its own water and if so, does the CaO rob the water away from the KOH solution freeing it up to make more methoxide?

If not, is there any benefit in putting the CaO in the methanol first, to adsorb the water as it is being produced?

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: New Methods #2. The Imisides Method

Hi Geewizztoo
A few considerations.
Most KOH is 90% purity. The other 10% impurity is water. I assume this water will be removed with this process.
As far as disolving the KOH in methanol, in my research there is a big question mark as to how much is actually converted into potassium methoxide. Some "Experts" say not much methoxide is produced and mostly all you have is KOH disolved in methanol while others say much more methoxide is produced. Apparently water is the limiting factor as to how much methoxide is produced so by removing water with this procedure you should make more potassium methoxide.

Water is only produced when the KOH is actually converted into Potassium methoxide. I assume the 10% of water impurity in the KOH is released when it is disolved in the methanol.

So it appears the formula for making this methoxide is 15g KOH and 15g CaO mixed into 150ml of methanol for every litre of WVO being reacted.

I anxously await your test results.

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

Hi Tilly, thanks for your considerations.
I'm going to make up a few different concentrations and try them out this weekend. I'll do them side by side with control samples without CaO.
My particular area of curiosity is whether the dessicated methoxide (or KOH & MeOH solution) is more tolerant of wet WVO.
A lot of the oils I use have high moisture contents and I have to put in a bit of effort to dry it out before the biodiesel process.
If dessication by CaO has benefits in this area, it would save me a lot of time.
As I mentioned earlier, I was trying to dry the WVO directly with CaO, seems like I may have been barking up the wrong tree.

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: New Methods #2. The Imisides Method

A few more questions Mark,

When adding CaO to WVO, from your reply I assume that the CaO would preferentially react with any water present rather than the FFA?
If the WVO was overdosed with CaO such that the oil was fully dried, would the surplus CaO react with the FFA at all?

Do you know how to calculate the amount of water produced by dissolving a given amount of KOH in methanol?
(x grams KOH/litre MeOH = y grams water)

In your method #2 at the 'make biodiesel' stage, is the dried methoxide more tolerant of water suspended in WVO, ie damp oil? Or would wet oil negate any benefits and create the ususal glop?

Yes, CaO will react with water in your WVO to form Ca(OH)2, but it won't react with the FFA unless there is excess water present to allow the Ca(OH)2 to dissociate.

But I think the idea of dehydrating the WVO chemically is fraught with problems, largely because it is so viscous. As you've discovered, CaO takes forever to settle in oil. You could perhaps try a coarser dessicant like calcium chloride "drierite" but I have no experience with that myself. The best option would be a heavy, dry liquid, like conc. sulphuric acid, which would probably dehydrate your WVO nicely, but you seriously don't want to be messing with stuff like that for a whole lot of reasons. I think the best way to dehydrate wet oil is the heating and settling process, with the water being tapped off through a bottom draining valve.

It's impossible to calculate the amount of water produced by KOH and MeOH without knowing the equilibrium constant. However, since the whole point of my method is that the equilibrium is pulled to the right by the addition of CaO (and to completion if enough of it is added) you can do the calculation and Wesley has I think done it for you.

But it's virtually impossible to work out how much CaO you need to sop up this water for the simple reason that it's a solid. If you weighed out say 2kg of lime, the vast bulk of that mass is tied up inside the individual grains, and you never know how much is exposed to the liquid and is available to react with the water. I used about twice as much (by sight) lime as I did KOH and that seemed to dehydrate the process enough to get enough methoxide in solution to get the reaction to proceed at RT. If you wanted to get technical about it, you could dissolve the KOH, let it cool to RT and then add the lime and monitor the temperature - it should warm as the lime reacts with the water. In general terms when it stops getting warmer the rxn has gone to completion.

The dried methoxide solution would result in greater tolerance of oil in your WVO, but only because the total amount is less in the mix. That is, rather than having water present from both your WVO and methoxide solution, there would only be water from the WVO

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: New Methods #2. The Imisides Method

Just thought of another question:
Does some of the KOH dissolve in its own water and if so, does the CaO rob the water away from the KOH solution freeing it up to make more methoxide?

If not, is there any benefit in putting the CaO in the methanol first, to adsorb the water as it is being produced?

Technically yes it would, but it wouldn't alter the overall reaction process.

There is no reason why you can't add the lime before the KOH - before or after makes no difference. The only problem with adding the lime first is that you wouldn't know when the KOH had dissolved.

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: New Methods #2. The Imisides Method

Hi Geewizztoo
A few considerations.
Most KOH is 90% purity. The other 10% impurity is water. I assume this water will be removed with this process.
As far as disolving the KOH in methanol, in my research there is a big question mark as to how much is actually converted into potassium methoxide. Some "Experts" say not much methoxide is produced and mostly all you have is KOH disolved in methanol while others say much more methoxide is produced. Apparently water is the limiting factor as to how much methoxide is produced so by removing water with this procedure you should make more potassium methoxide.

Water is only produced when the KOH is actually converted into Potassium methoxide. I assume the 10% of water impurity in the KOH is released when it is disolved in the methanol.

So it appears the formula for making this methoxide is 15g KOH and 15g CaO mixed into 150ml of methanol for every litre of WVO being reacted.

I anxously await your test results.

That's right - you guys might want to have a look at this - it explains how chemical equilibria work - the very basis of this method:

Le Chatelier's Principle

BTW, there is a bloke named Murf who used to be on this forum who's been making his bio with this method for a couple of years now. If he could be contacted he might have some comments

[Dr Mark Senior Member Find all posts View Profile Close Dr Mark]

Re: New Methods #2. The Imisides Method

Comment about lime availability. Some of you are having difficulty getting some. The problem is that it's an industrial chemical with no common domestic use so it's hard to find a retail outlet that would sell it. I'd suggest the following:

1. Do an exhaustive ring around of cement factories in your area. You might be lucky and find someone.

2. Approach a local hardware shop that sell the hydrated lime. Since they would get the hy-lime from a cement factory, ask them if they can also get some quicklime

3. As a last resort, you could ring the UNIMIN factory in Lilydale VIC, and ask them to send some to you. If you got enough of it sent at once, it may be economical. It's not a DG, so there should be no special transport or storage considerations involved. When I bought it over the counter I think I paid $12 for a 20kg bag. From memory it was a 90% purity product, with most of the rest of it being MgO

[WesleyB Donating Member Find all posts View Profile Close WesleyB]

Re: New Methods #2. The Imisides Method

Dr. Mark; I've found Calcium Oxide powder available from Fisher Scientific in the USA, 500 grams for $49 (USA dollars). A problem is that since the terrorist attack here they've tightened the screws on letting people order chemicals, but I'll try. I'll try to make biodiesel starting with 190 proof ethanol, using your method.

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

OK Dr Mark, Tilley et al, here’s my report on my preliminary experiments with CaO over the weekend. These were just a few quick trials to ‘have a look’ and by no means are the results definitive.

Its a bit long to post directly, so I've attached it as a word document so that the hardy can work their way through it.

There are probably several ways to do this, but due to the highly alkaline nature of the reaction mixture, water washing is not one of them.

Dr Mark, you say that water washing is not appropriate for this method, can you expand on this?
For my small test samples I used the 5% pre wash method and it seemed to behave as normal.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: New Methods #2. The Imisides Method

Hi Geewizztoo,

Of course the shape of the Dr Pepper bottle has been scientifically optimised to produce biodiesel. However, in a pinch, a Berri bottle is an acceptable second choice.
Thank you for the test results.
Did you do any 3/27 testing?

A few observations.
With the formula calling for 14g KOH per litre of oil reacted, because you used 200ml methanol per litre of oil reacted you should pass the 3/27 test using the normal single stage method with oil titrating up to about 6KOH. By using oil titrating 4 KOH your first three batches should have been very high conversion with or without the CaO.

You felt your third batch reacted almost instantly mostly because additional heat and pressure was generated is my understanding. Whether the reaction is exothermic or endothermic seems to be in some doubt. Some sites say one and other sites say the other.
The one thing that is certain (as far as I can tell) is that if it is exothermic it does not generate much heat.
Another explanation for the increased heat and pressure might be that perhaps there was some undisolved KOH available and when you shook the bottle for the reaction the KOH dissolved.

Colour Difference
I assume batch 1, 2, and 3 came out of the same pot of heated WVO and were identical in that respect. If that is the case I can think of three things that will result in a difference in colour.
1. If you perform an acid stage the biodiesel will be darker in that sample.
2. The sample containing a lower conversion biodiesel will be darker.
3. The sample that has not had as much glycerine settled/washed out will be darker. The warmer the biodiesel the quicker the glycerine settles out.
1a. You did not do an acid stage so that leaves that out.
2a. By the amount of chemicals you used all three batches should be pretty much the same very high conversion.
3a. I would probably allow the three samples to settle over the next week or three and watch them lighten up as the glycerine settles. And then check if there is still a difference in colour.
3b. Or if you want quick results do a Dr Pepper wash and then dry and compare the colour.

Batch number 5 was another kettle of fish.
The oil titrated 14 and did not even separate using this latest "Foolproof titrationless" method. Déjà vu or what. That is exactly what happened when I tested the old "Foolproof Titrationless" method.

I am so disappointed that Mark did not perform any meaningful testing to support his claims for this procedure

Once again thank you for your time and information. If you perform any further testing I am sure everyone would love to hear your results

[timorcoco Donating Member Find all posts View Profile Close timorcoco]

Re: New Methods #2. The Imisides Method

The most appealing aspect of this method is the promise of less soap made due to less water formation at
meth and reaction stages .
perhaps a soap test would be in order - by titration or water mix
Have you done any checks Mark , and could you please explain further why you feel water wash of product is unsuitable.
maybe this method + woodchip drywash could be the go . . . . . .

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

Hi Tilley,

I find that although the Berri fruit juice bottle is not hydrodynamically optimised for rheological flow, it functions well as a Dr Pepper analog. And they're a lot more common in my recycling bin!

Firtsly;

So it appears the formula for making this methoxide is 15g KOH and 15g CaO mixed into 150ml of methanol for every litre of WVO being reacted.

I noted your comment a few days ago, but was puzzled where it came from - then I realised it was from Marks original post:

Methoxide solution:
Dissolve about 10% w/v KOH in methanol – for example, 2kg KOH in 20L MeOH.

Biodiesel manufacture.
Now just add the methoxide solution to the WVO in your normal quantities at room temperature. I generally use a mixing ratio of 100:15.

But I assumed the '2kg KOH in 10L MeOH' was just an example for demonstrating the maths as it opened with 'Dissolve about' so I went the the comment of 'add the methoxide solution to the WVO in your normal quantities'

Funny how things can be interpreted in different ways. Using only 150ml/L of MeOH would make more sense, as I it occured to me when I was doing the first three samples that these ratio's should easily produce high conversion bio with or without CaO.

Did you do any 3/27 testing?

In my haste, it completely slipped my mind to do some 3/27 testing, but the samples are stll sitting on the bench and I will do it when I get a moment. I'm confident no.s 1 to 3 will pass with flying colours.

Whether the reaction is exothermic or endothermic seems to be in some doubt. Some sites say one and other sites say the other.

Really? I haven't read any debate on this. In my experience its always exothermic. I have a digital thermometer on my equipment and it always indicates a 5 or 6C increase when the MeOH solution is added. In fact I use it as an indication of a good reaction.

Samples 1 to 3 were taken from the same pot of heated oil and reacted sequentially. My theory for no.3's accelerated reaction is this: I reckon there was residual heat in the electrically heated pan and as the level was depleted by the removal of samples 1 and 2, sample no.3 was a little warmer. I used a meat roasting probe thermometer, which is not very accurate as the increments are so course maybe +/-5C at best.

On the colour difference issue, yes you're right they have already evened out. It was a very hot day here yesterday (37C) and all three are already a nice crystal clear, amber colour.

Batch 5; Another kettle of fish.
I agree, but there's not that many homebrewers out there that would take on the challenge of +14 titration oils. To the method's credit, if I had started with 18g KOH in 200ml of MeOH then it might have worked first time. A standard single stage base reaction without CaO would stand no chance of being successful.

Adding CaO to the methanol is a messy business. Yes it settles, but when it does, the slurry doesn't cake at the bottom and any slight disturbance of the container sends the particles back into suspension, like one of those Christmas snow domes.

You'd also have to allow a bit extra liquid as you're going to lose a few litres in with the slurry. Then there's the issue of disposal. Where can you dump this highly caustic, methanol laced slurry?

As Mark said, this heterogeneous chemical (solid & doesn't dissolve) can only react through the surface area of each particle. So in my opinion, the methoxide would have to be kept churning for an extended period of time to be effective and allow the moisture to diffuse into the particle.

Dr Mark, do you know if; once the surface of the CaO particle is fully reacted with water, does this encapsulate it like a candy coated M&M and prevent the ingress of further water into the core or will it keep adsorbing water until its all converted into Ca(OH)2?

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: New Methods #2. The Imisides Method

Hi Geewhizztoo,

Hi Tilley,Firtsly;
I noted your comment a few days ago, but was puzzled where it came from - then I realised it was from Marks original post:
Methoxide solution:
Dissolve about 10% w/v KOH in methanol – for example, 2kg KOH in 20L MeOH. Biodiesel manufacture.
Now just add the methoxide solution to the WVO in your normal quantities at room temperature. I generally use a mixing ratio of 100:15. But I assumed the '2kg KOH in 10L MeOH' was just an example for demonstrating the maths as it opened with 'Dissolve about' so I went the the comment of 'add the methoxide solution to the WVO in your normal quantities'

Yes, the instructions and advice Mark gives changes from post to post.
The other thing you need to be aware of is that Mark has made it clear that he is not concerned about achieving a very high conversion fuel. This procedure is not about producing very high conversion biodiesel.

Funny how things can be interpreted in different ways. Using only 150ml/L of MeOH would make more sense, as I it occured to me when I was doing the first three samples that these ratio's should easily produce high conversion bio with or without CaO.

Yes, if all you are concerned with is achieving separation then 150ml methanol per litre is plenty for most WVO. Because Mark did not do any testing with high titration oil he was not aware of the problems high titrating oil presents.
I do a 2 stage reaction with the first stage at 140ml methanol and 8.5g KOH per litre of oil reacted and achieve great separation in the first stage. Of course my oil does not titrate anywhere near 14KOH

Batch 5; Another kettle of fish.
...To the method's credit, if I had started with 18g KOH in 200ml of MeOH then it might have worked first time.

It might have, but then again it might not have. And one of the great claims for this amazing new procedure is that no titration is required. And do not forget you used an extra 33.3% methanol over the formula requirement.You did not even achieve separation, never mind very high conversion biodiesel which is what almost everyone except Mark is talking about.

A standard single stage base reaction without CaO would stand no chance of being successful.

Just like this one was not.

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: New Methods #2. The Imisides Method

I do a 2 stage reaction with the first stage at 140ml methanol and 8.5g KOH per litre of oil reacted and achieve great separation in the first stage.

Yes, I use 'Neutrals' method too and have been very happy with it for titrations under 9 KOH. But I sometimes get a batch which goes beyond double digits, so then I have to switch over to the acid/base (A/B) method and it turns biomaking from a one day operation into two. If Mark's method was truly independant of titration then it would be a big time saver over the A/B method. Although the yields are always going to be lower than A/B. In my test sample #5 when I finally achieved separation, almost one third of it was by-product. I guess this is to be expected using 250ml of methanol, plus all the soap from neutralising the high levels of FFA.

More testing is required to see if the use of CaO has benefits for high titrating oils. If the CaO is capable of soaking up a high proportion of the water from the KOH/methanol solution, then the upper limits of titration might be raised from 8 or 9 to who knows? Dr Mark, is there any way of measuring the residual water content of the KOH/methanol solution?

Just found this website, and it indicates the adsorption rate of water in CaO is very slow. Looks like it could be several days to get up to the maximum 30% weight gain, however this is for dehumidifying air.

Desiccant Chart Comparisons - SorbentSystems.com