What does it mean when the test gives you cloudy methanol but no drop-out.?

3ml bio into 27ml methanol (it might have been 26.5ml of meth)..
I got cloudy methanol (yellowish tinge) and stayed cloudy forever but no drop-out seen after 5 hours. (1/2 hour inspections)

Bio was washed and dried..

does it have an oily layer on top?

quote:

Originally posted by RickDaTech:
does it have an oily layer on top?

Nope..nothing.. just a bit cloudy..

Murphy,

My guess is you have about 100% conversion of available triglycerides (TG) to biodiesel (BD), monoglycerides (MG) and diglycerides(DG).

TG are not soluble in methanol, so no drop out indicates no free TG.

DG and MG are somewhat soluble in methanol, so cloudiness would indicate presence of DG and MG.

This means pretty good, but not quite, ASTM standard B100, BD.

Wait a few days, the test vial now has an overwhelming amount of methanol to DG and MG. The DG and MG will convert to BD given enough reaction time at such a large ratio of methanol to DG and MG.

Enbio, please check your private messages.

quote:

Originally posted by producer:
Murphy,

My guess is you have about 100% conversion of available triglycerides (TG) to biodiesel (BD), monoglycerides (MG) and diglycerides(DG).

TG are not soluble in methanol, so no drop out indicates no free TG.

DG and MG are somewhat soluble in methanol, so cloudiness would indicate presence of DG and MG.

This means pretty good, but not quite, ASTM standard B100, BD.

Wait a few days, the test vial now has an overwhelming amount of methanol to DG and MG. The DG and MG will convert to BD given enough reaction time at such a large ratio of methanol to DG and MG.

Producer,
Thanks.. Does this mean the cloudiness should go away as the conversion takes place (slowly)?

I've dont the Jan Warnqvist test on other batches.. What is strange is the instructions say "Dislove exactly 3ml into 27ml".. I've done some experiementing and have dissolved the 3ml into just 20ml of methanol and still got crystal clear results.. (albeit a bit yellowish).

I started with 27, then to 25, then to 20ml and when the results where all the same, I began to question the validity of the test.. I guess I just dont understand it completely but you just answered a few questions for me..

Please correct me if I am wrong but as I understand it, No glycrides means perfect conversion ? The more glycerides, the more problems with the test results? Different glycerides produce different problems within the test?

If this is the case, I might know why..
I'm on my 3rd bag of KOH now... This time, the bag had clumps in it.. (Flakes that stuck together).. I had one clump that was twice the size of a baseball!!! Yup.. But being an hour drive from the chemical supplier, I decided to just use the loose flakes that still looked good.. While scooping the stuff out, I do occasionally get small clumps that are the size of grapes..Not many.. Maybe 3 or 4 per 2000 grams used.. I just mix them in and dont worry about it.. perhaps I should start adding an extra 200grams to my batches just to make up for the clumps?

Thanks for all your answers..

Murphy,

I have run many of these tests. Many results have been "cloudy with no drop out". I usually keep the test bottles (sealed) around for a couple weeks or more. The "cloudy - no drop out" samples always cleared up in several days to a week or so.

The original write-up of the test by Warnqvist called for 50 ml of BD in 450 ml of methanol, for a 1:9 ratio. The smaller amounts i.e. 3 ml BD, 5 ml BD, etc. are an attempt to preserve the original ratio, while saving on the amount of methanol. I use 5 to 45 because it is very easy to draw 5 ml of sample into a plastic BD syringe.

If you reduce the amount of methanol per the amount of BD, then you are providing less solvent for the same amount of BD. The lower the amount of solvent that remains clear with no drop out means you have very high conversion BD. The results based on 9:1 can, somewhat, be compared with others who do the test with the same ratio.

Indeed, no glycerides would indicate perfect conversion.

In my testing, everytime I get a "cloudy - no drop out" result can usually be traced back to not enough catalyst available at the end of the reaction.

Producer,
Ever get one of those Eureka!! moments..? I just had one because of your explanation.

Thanks,

I guess it is indeed those grape sized clumps. I probably get 100 to 200 grams of them per 2000 grams of KOH I use.. That would explain the cloudyness.. Sounds to me like I'm just on the lower edge of perfect conversion and am there because of those stupid clumps of KOH in the bag..
I think next reaction I do I'll just add an extra 200 grams of good stuff on top of the clumps and see if that makes up for it..

Thanks VERY much.. I highly appreciate your response..

Why not just mash the clumps up?

quote:

Originally posted by fabricator:
Why not just mash the clumps up?

I think the reason the clumps form is due to moisture in the bag somehow. Once moisture enters the KOH flake, it sets it off somehow and ruins it.

While I am not 100% positive about this, I've read on this forum where someone had some clumped up stuff and everyone said it was no good.

I think there is a big difference between a few flakes sticking together and a clump where the flakes have melded and merged into a solid mass.

quote:

Originally posted by steved:
hi murphy, some people mix the lye with water before they use it. i am not sure water messes it up. every bag i have bought has had clumps in it. they break up easy enough.

Mixing it with water to make biodiesel??? HUH???

I can understand mixing it to make soap..

Please correct me if I am wrong but I thought the conc aqueous method involved purchasing the liquid form of NaOH.. Am I to understand these guys are just mixing it with water themselves?

quote:

Why not just mash the clumps up?

You will be wanting to discern between simple aggregating of your pure KOH versus a clumping effect facilitated by moisture where you will be producing a carbonate molecule (can't remember which one) which has lost its ability to perform as a catalyst. The latter requires some air as well as moisture.

Glenn