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New Methods #2. The Imisides Method

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  • g'day everyone,
    For some reason, when I edited my above post answering murf's question a flag appeared that said it was flagged for spam and would need approval. I wonder if this one will post?

    PS it seems this one posted. I wonder if this edit will also post. If it does I will re-post my above post.
    tillyfromparadise
    Senior Member
    Last edited by tillyfromparadise; 30 March 2022, 03:41 PM.

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    • Hi Murf,
      I typically use 10g KOH per litre WVO. That would save you 1/3 the cost of your KOH. Apparently, the
      CaO removes about 15% of the methanol from the methoxide . That is the same as throwing 30 litres of methanol away from every 200 litres drum you buy.
      I am sorry to hear you went to the expense of buying 10 years worth of CaO. How much CaO did you buy? I see Mark recommends 20kg of cement powder for every 180 of methanol. Do you use that much CaO?
      It takes a minute or so to do a titration and very minimal brain power. Even I can titrate.
      How long does it take for you to mix the CaO into the methoxide and then drain it off after a few days of settling?

      Tilly
      PS- As I recall, the amount of KOH was increased from 15g to 20g after I performed some testing that showed 15g KOH was not enough for some high titration oil. Good to see you are not using high titration oil.

      Comment


      • Tilly; You are in error . Adding calcium oxide to methoxide solution does not remove methanol from it . Calcium Oxide bonds with one water molecule to produce calcium di-hydroxide . One calcium oxide molecule removes one water molecule from solution and the calcium hydroxide solid settles out , removing water from the methoxide solution . This pushes the reaction of sodium hydroxide with anhydrous methanol to the right , which increases the concentration of methoxide .

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        • Hi Wesley,
          Mark reported needing to add extra methanol because some was removed with the Cement powder after it settled out. That is not CaO and this was my error.

          Water and CaO results in calcium dihydroxide which is a solid. CaO is also a solid.
          Is it your thought that when the CaO and methanol are mixed together the methanol does not "wet" the CaO?
          Do you think that when the CaO settles to the bottom there will be a "dry" powder bottom layer consisting of a mixture of CaO and calcium dihydroxide and no methanol? Do you think that after you pour the methoxide off, the remaining layer of CaO and calcium dihydroxide will be a dry powder and contain no methanol?
          Have you tried it?
          tillyfromparadise
          Senior Member
          Last edited by tillyfromparadise; 1 April 2022, 06:09 PM.

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          • You are right Tilly . Removing the methoxide solution from the solid calcium di-hydroxide leaves a solid with some methanol solution on it . In a small quantity using vacuum filtration and paper filter paper might not be practical . I expect methoxide solution might decompose the filter paper . I used calcium oxide - methoxide solution once or twice at room temperature with stirring . Based on the quick color change , the reaction rate appeared to me to be faster . I used virgin corn oil in that experiment . I've moved to a new residence and I'm not sure I could find my lab notebook I used on this experiment . A drawback to using calcium oxide is the production of calcium soaps in the biodiesel which is difficult to remove .

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