"Methacid" method

[Julian]

OK ... Think it's time to come out of the shadows and divulge one of the much speculated "secret" methods I've tried.

This is Paul's (Carrington's) idea so I take no credit for it's merit or otherwise.

I have to say at the outset that the process involves operations I consider potentially dangerous, and I'd recommend that it is not tried unless you are careful, knowledgeable of chemicals (especially acids) and use the required personal protection equipment.

I'm not putting myself forward as particularly careful and certainly not knowledgeable about chemistry, but I did seek third party advise from a friend who has a PhD in chemistry and survived to tell the tail.

The method is very similar to Paul's titrated acid wash method, except it uses no water.  Paul believes that there is a chance this method may prevent the formation of HMPEs.

The sequence is as follows ...

Process normally to a 3/27 pass, by whatever method you choose.

Allow Glycerol at least 8 hours to settle then drain.

(By draining the lower pipe work I managed to settle over 24hrs, draining several times)

Titrate to quantify acid requirement ... probably a bit of a mix with the pump before hand will collect glycerine off the processor walls and give a more representative result.  I believe a concentrated acid is required to eliminate as much water as possible.

Add acid to Methanol, the acid being circa 20% of Methanol quantity.

(This is the dangerous bit!  I used roughly double the Methanol quantity, believing it to be slightly less hazardous.  The reaction is highly exothermic and the acid should be added very slowly.  I did so using a pipette, but even then an audible fizzing and gluping was noticed if more than a few drops were added at one time.

Add "Methacid" to processor and mix, say 20 mins

(My plan was to introduce the "Methacid" via the venturi, but again I had concerns about this.  There were pockets where the "Methacid" could come into contact with copper and brass and not have a chance to get washed away by the bio.  So I decanted bio from the sample point and added small quantities of the "Methacid" to the bio and entrained that into the processor via the venturi and all went well)

Demeth the bio.

( I usually WBD, but as the bio had cooled to around 20°C, the glycerin had been removed and there's the school of thought that WBD can promote HMPEs, I decided to bubble the Methanol out.   So I added Coldflow, mixed and pumped out.)

Pump to settling tank.

(I bubbled for 24 hrs to remove Methanol)

Settle for X days as you see fit.

(After a week the bio was still cloudy, but gave the best 50/50 test I've ever seen.  A test with litmus paper showed a pH of around 7.  To remove the cloudiness I returned the bio to the processor and distilled out about 2 litres of Methanol ... unless for prolonged periods, bubbling is obviously only good at removing residual Methanol)



I've still to get a controller for the redundant freezer and run chilling tests, but I'll stick a sample in the kitchen freezer and report results.

I have to say that, having tried it, unless it returns startling results in the way of HMPE reduction, I'll not be trying the process again ... I found it rather scary!  That said, many thanks to Paul for hitting on another variation of the process, these things have to be tried, let's hope it has some effect on HMPEs ... watch this space!

[Head Womble]

The mixing sounds scary, I'm not doing another batch just yet but may well try this in conjunction with water washing.
I need to get some acid first though.

[Julian]

Be very careful Mark.  I couldn't bear it if any thing happened to you ... before you've returned my concrete mixer.

Unless it yields a reduction in HMPEs, there's little to be gained by this method and quite a lot to loose!  I recon Paul's titrated acid wash is much safer, works brilliantly and we've proved water washing reduces HMPEs (some claim it eradicates them).  If you haven't tried that yet it's well worth a go.

[nigelb]

Providing this method has some substance would it not be more prudent to add the acid directly into the methanol by having the tip of the pipette under the surface of the methanol instead of adding dropwise to the surface.

Nige

[Head Womble]

Julian, I've been doing the titrated water wash for a while now and getting on very well with it.
But I'm happy to to do some testing if we can move things forward even further.
I'm using brick cleaner (34% hydrochloric) for the water washing but will need some 99% stuff for these tests.

Nige, I'm thinking of rigging up a small funnel and some small bore air line pipe,
this way the acid could be added from a safe distance and the end of the pipe can be below the surface of the meths.


Would there be a benefit from making up a large batch, say 10 or 15 Liters, and decanting the required amount for each reaction.
The acid could be added a small amount at a time over a few days allowing the mix to cool and stabilise between doses.

[Chug]

It sounds like a lot of complication and feckin about to me, unless you can affect the structure of the chain length/carbon bonds to make shorter/bent chains then even with the best feedstock you are gonna get HMPE's when it gets near to, or drops below freezing.

[Julian]

The idea of immersing the pipette or tube in the Methanol, doesn't sound like a good one to me.

If there's even a remote chance of the Methanol migrating up the tube, the reaction might be quite violent.  I'm thinking about the issue of adding acid to water rather than the otherway round.

I know the acid is denser than Methanol but it's still a risk.  One time when cleaning up after a titrated acid wash, I ran water from the tap into a very small amount of conc Sulfuric, thinking it was Methanol, and the reaction was quite startling.  Luckily because it was running water from the tap, the volume quelled the reaction quite quickly, but it certainly taught me a lesson.

[Head Womble]

The idea of immersing the pipette or tube in the Methanol, doesn't sound like a good one to me.

If there's even a remote chance of the Methanol migrating up the tube, the reaction might be quite violent.  I'm thinking about the issue of adding acid to water rather than the otherway round.

I know the acid is denser than Methanol but it's still a risk.  One time when cleaning up after a titrated acid wash, I ran water from the tap into a very small amount of conc Sulfuric, thinking it was Methanol, and the reaction was quite startling.  Luckily because it was running water from the tap, the volume quelled the reaction quite quickly, but it certainly taught me a lesson.

Very good point Julian, if it did this with my idea it could spit acid out of the funnel.

But as long as the end of the pipe is above the meths level so it's drop feeds it should be ok, what do you think.

[Julian]

The idea of immersing the pipette or tube in the Methanol, doesn't sound like a good one to me.

If there's even a remote chance of the Methanol migrating up the tube, the reaction might be quite violent.  I'm thinking about the issue of adding acid to water rather than the otherway round.

I know the acid is denser than Methanol but it's still a risk.  One time when cleaning up after a titrated acid wash, I ran water from the tap into a very small amount of conc Sulfuric, thinking it was Methanol, and the reaction was quite startling.  Luckily because it was running water from the tap, the volume quelled the reaction quite quickly, but it certainly taught me a lesson.

Very good point Julian, if it did this with my idea it could spit acid out of the funnel.

But as long as the end of the pipe is above the meths level so it's drop feeds it should be ok, what do you think.

Just wish I'd paid more attention to Chemistry when at school!  I know what I did worked, you just need to take things easy and carefully.  I was using a 3ml pipette, adding two or three drops at a time and giving the flask a gentle mix to ensure the acid was dispersed.

I recon a small volume in a pipette is probably safer than the whole quantity in a funnel.  If anything goes wrong, the whole volume dumping into the methanol at one time wouldn't be good!

Keep it simple and take your time.

[Head Womble]

I never took any notice in chemistry either,
I know mixing acid and base wasn't good,
and phenolphthalein could give you serious runs,
but apart from that playing with bunson burners was fun.

[Julian]

Would there be a benefit from making up a large batch, say 10 or 15 Liters, and decanting the required amount for each reaction.
The acid could be added a small amount at a time over a few days allowing the mix to cool and stabilise between doses.

Sorry, missed this bit! I'd say no.  The concentration will vary batch to batch and it's nasty stuff to have hanging around.  Probably better to keep the acid in a comparatively small glass container in a safe place.

[photoman290]

Julian, I've been doing the titrated water wash for a while now and getting on very well with it.
But I'm happy to to do some testing if we can move things forward even further.
I'm using brick cleaner (34% hydrochloric) for the water washing but will need some 99% stuff for these tests.

Nige, I'm thinking of rigging up a small funnel and some small bore air line pipe,
this way the acid could be added from a safe distance and the end of the pipe can be below the surface of the meths.


Would there be a benefit from making up a large batch, say 10 or 15 Liters, and decanting the required amount for each reaction.
The acid could be added a small amount at a time over a few days allowing the mix to cool and stabilise between doses.

 34% is the highest concentration you can get with hydrochloric acid. any higher and it it is a gas, according to Wikipedia, just in case you thought i might know what i  am talking about.

[Head Womble]

Julian, I've been doing the titrated water wash for a while now and getting on very well with it.
But I'm happy to to do some testing if we can move things forward even further.
I'm using brick cleaner (34% hydrochloric) for the water washing but will need some 99% stuff for these tests.

Nige, I'm thinking of rigging up a small funnel and some small bore air line pipe,
this way the acid could be added from a safe distance and the end of the pipe can be below the surface of the meths.


Would there be a benefit from making up a large batch, say 10 or 15 Liters, and decanting the required amount for each reaction.
The acid could be added a small amount at a time over a few days allowing the mix to cool and stabilise between doses.

 34% is the highest concentration you can get with hydrochloric acid. any higher and it it is a gas, according to Wikipedia, just in case you thought i might know what i  am talking about.

That would explain why I get a vissable vapor gassing off when the container is opened,
it spooked me the first time I opened it.

[julesandtash]

The only problem I see with adding Conc sulphuric (or hydrochloric) acid to methanol as opposed to water is that the boiling point of the methanol is much lower (65C as opposed to 100C) so the mixture is more prone to boiling and therefore spitting everywhere (and liberating flammable vapour as opposed to steam)

I quite happily add 500ml of 96% sulphuric acid to 20 litres of water in a 25 litre carboy for my acid washes with no problem. I just measure the acid into a plastic jug (from the 25 litre carboy I received it in) and then slowly pour that (via a plastic funnel) into the top of the water container.
Then I swill out the jug with some cold water and pour that in as well.

I would be quite happy to do the same with methanol personally,  I just dont really see the point.

As it stands with the water method, after draining off the water from the washes you just need to dry the bio by your chosen means, liberating clouds of steam to the atmosphere (harmless) or condensing it into distilled water. Also the water is, depending on whether you have a meter or not, either free or very very cheap. Methanol is the best part of 50p per litre!

The method also means that any residual sodium sulphate (or the salt of whatever acid you happen to use) is washed out,

With the 'meth acid' process, you need to either drive off the methanol to the air (not very enviromentally friendly and potentially flammable) or condense it.
Also, you then need to settle the bio to let anything settle out (which hopefully the salts will but what if they dont?). That means an extra settling stage that is not needed with the water wash method.

Peronally, whilst I would be happy mixing the chemicals, I wont be trying this method as :
1. I am happy with the titrated water process
2. I have given away my condenser so could not condense the methanol and dont fancy wasting it to the air.
3. Dont have the room in my new layout for an extra settling tank of 300+ litre capacity

I am certainly not criticising Paul's work in any way, he really is a true pioneer and a gent for sharing his methods with us, I just dont think this is a particularly realistic process for home users.

[Carrington]

Hi all
A agree with all the comments about mixing the acid and meth and yes it does carry more hazards than the water wash.
The reason I used this way in the factory was so I could reclaim the meth and not have it contaminated with water. Also when going over to dry wash filter any sodium sulphate created is much easer to filter out or settle. This way I could go straight into filtering after de-meth and the filters would last many many times longer.
I look forward to see how this turns out but can understand why people may not choose to go down this route.

Paul