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The Methoxide Mixing
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BioDiesel Class 101

Class # 4 - Methoxide

    Reasonable caution is advised when mixing methoxide because you will be handling caustic chemicals. Provided you follow common sense guidelines and use due care you should be safe. Because potentially hazardous fumes can be present, please mix methoxide outdoors with adequate ventilation & wear proper chemical protective "PPE or "Personal Protective Equipment" outerwear. Most of these can be purchased locally or online or improvised. Use a Rubber or plastic apron preferably with sleeves, Full face shield, Rubber gloves with cuffs folded to the outside and rubber boots should be worn. An assistant with a charged water hose should be nearby in case of spillage to wash off your skin. Chemical filter masks are not effective with methanol so do this outside & use forced ventilation such as a fan if possible.

    Methanol (wood alcohol) is mixed with Lye to form Methoxide the chemical used to convert WVO into the BioDiesel Methyl Ester that we desire. Methoxide when combined with heated WVO and mixed for an hour will combine to form Methyl Ester BioDiesel. Be sure to read our PGB book so you know all the details.

    When Lye is mixed with Methanol (alcohol) it creates heat and forms Methoxide. The Lye normally comes in bead or flake form & is contained in a plastic sack. You need to keep the lye in a SEALED container right after cutting open the plastic bag it comes in because it will quickly begin absorbing moisture right out of the air. We suggest sealing it up in a clean 5 gallon plastic pail that you have put a GAMMA SEAL BUCKET LID onto. Google the internet for a GAMMA LID, they work very well for this. Once the Gamma Lid is firmly attached to your 5 gallon plastic bucket, slowly and carefully empty the entire 50LB sack of Lye into the bucket & after wiping off the sealing ring screw on the airtight lid to seal it up. Use a dust mask & DO NOT breathee ANY LYE DUST. be sure to wash yourself thoroughly afterwards.

    Using the amount of Lye that the Titration indicates, we mix it with the optimum amount of Methanol (read our PGB book for details) vol/vol with the WVO to be processed.

    In our previous example we were processing 40 gallons of WVO so as an example if we desired to use 22.5% methanol as vol/vol with this WVO, we would need 9 gallons of Methanol alcohol.

    So we hypothetically combine 9 gallons of Methanol with the required amount of Sodium Hydroxide. Don't worry much about a gram here or there. +/- a few grams either way isn't going to make much difference provided you are making a 40 gallon batch.

    Caution: Caution should be exercised when mixing Methoxide because it contains alcohol (a highly flammable liquid) and caustic Lye (Sodium Hydroxide). When combined, they form Methoxide which takes on the characteristics of both which means Methoxide is flammable, caustic and can be absorbed through the skin. You should not breathe the fumes so always use adequate outdoor ventilation when mixing these two chemicals. If splashed onto the skin, Methoxide can give you a nasty chemical burn so whenever handling Methoxide, be safe and always use a plastic chemical apron with sleeves, good chemical resistant gloves, a full face shield (not simply goggles) & rubber boots. Have a charged water hose nearby in case of spills or splashes. Note: Our ABP book Here details how to build a sealed Methoxide mixer to eliminate potential exposure.

    The chemical reaction of combining these two chemicals produces exothermic heat, be careful regarding the order you combine them in so that the reaction does not get out of control and boil over. The exothermic reaction temperature may be near 120F degrees and Methanol alcohol boils around 140F so combine them slowly. Always mix the Lye into the Alcohol, never the other way around. Do not just dump the Lye into the alcohol in one huge dump, instead try to spread it around. Mixing the Alcohol into the Lye can cause an uncontrolled exothermic heat reaction which can boil out violently & splash you in the face. If you do not have a container large enough for 9 gallons + head space for mixing, use two smaller 5 or 6 gallon containers.

    If you mix Methoxide in a plastic container, it must be made of heavy duty thick plastic and be able to withstand at least 120F degrees, when sealed plus it needs to be able to hold a moderate amount of pressure, be both air & liquid tight. Making Methoxide outside is always highly recommended.

    Never mix Methoxide with or in anything made of Aluminum since Lye rapidly eats Aluminum. We use a 5 gallon plain steel paint pail with a steel lid that we purchased for a few bucks from our local paint store. You should always mix Methoxide outside & have good ventilation to prevent fume build up.  Methods of mixing can include the use of a drill operated mixing paddle if your very cautious of fumes, spillage & sparks when mixing to prevent sloshing it around. You can use a heavy duty plastic carboy container if desired. Although not needed, the 5 gallon steel mixing pail we use has a spigot which we plumbed in near the bottom of it for easy & safe emptying into our Methoxide holding pails. We mix Methoxide in the steel mixing container through the bung hole in the lid & then drain it out the spigot and into a 5 gallon steel closed top drums which we keep well capped (formerly an Isopropanol alcohol containers) for short term storage (under an hour) until use. We wear our PPE (personal protective equipment) and periodically rock these containers back & forth to help the contents mix while we monitor the temperature. When they start to cool down we know the reaction between the Alcohol & Lye is complete & the Methoxide is ready to use. Do not make your Methoxide more than a few hours in advance because keeping it air tight is difficult. Air and moisture infiltration can cause it to severely degrade.

And you thought we forgot.....

  1. List the Methoxide hazardous that you need to be aware of?

  2. Since Methoxide is hazardous, what should you wear to protect yourself?

  3. What does PPE stand for anyway?

  4. Should Methoxide be mixed outside & why?

  5. What should be charged & ready?

  6. How hot does Methoxide get when mixing?

  7. Does it matter if the Lye gets put into the Methanol or the other way around & why?

  8. What does the Methoxide do to skin nerves if contact is made?

  9. What happens to Methoxide if it is left exposed to the air?


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Last modified: 11/26/16