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Thread: Making triacetin from glycerol

  1. #1
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    Making triacetin from glycerol

    Last August an Irish gentleman mentioned making triacetin from the glycerine byproduct from biodiesel production. I decided to make some triacetin. The Chinese make thousands of tons of it for domestic use and export. It is good for use as a fuel additive, as a food additive in cosmetics and drugs. It is something that could give cash value to waste glycerine from biodiesel production. So, Put 51.3 grams glycerine 125 ml glacial acetic acid and 0.9ml concentrated sulfuric acid into a 500 ml round bottom boiling flask. Heated repeatedly for a long time (days), gradually increasing the temperature. Then refluxed for about 8 hours, then distilled off about 24ml with a still head thermometer temperature of 101-103 degrees centigrade. Poured 125 ml more glacial acetic acid into the 500 ml flask. 5 days later began heating at 5 PM then reluxing about 8 hours then distilled off 64 ml distillate at a still head thermometer temperature of 107 degrees centigrade. At that time there was a noticeable colour change from colourless to yellow-brown. Poured 125 ml more glacial acetic acid into the 500 ml still pot. Heated up gradually, refluxed for an hour then distilled off 145 milliliters of distillate with a still head thermometer temperature of 112-118 degrees centigrade. Towards the end of the distillation my hot vegetable oil bath under the still pot was 168 degrees centigrade, so with my set up, rather than turn it up , I extracted the still pot contents with 100 milliliters saturated aqueous sodium chloride (table salt) solution. Then extracted with 100 milliliters of distilled water in a separatory funnel. The product was transluscent. I dried with 17 grams anhydrous sodium sulfate (this might have been unnecessary). Decanted the clear transparent yellow liquid off the drying agent to get 113.2 grams, 102 milliliters of what is probably triacetin. This is the first time I made it. It could be done quicker than I did it (months). A problem is purifing the glycerine byproduct from biodiesel production enough to make acceptably pure triacetin. The purity of starting chemicals I used was Pharmacy grade glycerol, Concentrated sulfuric acid 95-98%, Glacial acetic acid 100.0% (so it says on the label). I'm not going to spend the money to have the local analytical lab test the product with IR spectroscopy or gas chromatography.

  2. #2
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    Re: Making triacetin from glycerol

    Hi Wesley,

    I find how you have written the above post nearly impossible to read. Often you have very interesting things to say, but I sometimes find it very hard to read.
    Using paragraphs and breaks at strategic points would make it much more readable

    I think the following organization of your above post is much easier to read.

    " Last August an Irish gentleman mentioned making triacetin from the glycerine byproduct from biodiesel production. I decided to make some triacetin.
    The Chinese make thousands of tons of it for domestic use and export. It is good for use as a fuel additive, as a food additive in cosmetics and drugs.
    It is something that could give cash value to waste glycerine from biodiesel production.

    So, Put 51.3 grams glycerine 125 ml glacial acetic acid and 0.9ml concentrated sulfuric acid into a 500 ml round bottom boiling flask. Heated repeatedly for a long time (days), gradually increasing the temperature. Then refluxed for about 8 hours, then distilled off about 24ml with a still head thermometer temperature of 101-103 degrees centigrade.
    Poured 125 ml more glacial acetic acid into the 500 ml flask.

    5 days later began heating at 5 PM then reluxing about 8 hours- then distilled off 64 ml distillate at a still head thermometer temperature of 107 degrees centigrade.
    At that time there was a noticeable colour change from colourless to yellow-brown.
    Poured 125 ml more glacial acetic acid into the 500 ml still pot. Heated up gradually, refluxed for an hour then distilled off 145 milliliters of distillate with a still head thermometer temperature of 112-118 degrees centigrade.
    Towards the end of the distillation my hot vegetable oil bath under the still pot was 168 degrees centigrade, so with my set up, rather than turn it up , I extracted the still pot contents with 100 milliliters saturated aqueous sodium chloride (table salt) solution. Then extracted with 100 milliliters of distilled water in a separatory funnel.
    The product was transluscent.

    I dried with 17 grams anhydrous sodium sulfate (this might have been unnecessary). Decanted the clear transparent yellow liquid off the drying agent to get 113.2 grams, 102 milliliters of what is probably triacetin.
    This is the first time I made it. It could be done quicker than I did it (months).

    A problem is purifing the glycerine byproduct from biodiesel production enough to make acceptably pure triacetin.
    The purity of starting chemicals I used was Pharmacy grade glycerol, Concentrated sulfuric acid 95-98%, Glacial acetic acid 100.0% (so it says on the label).
    I'm not going to spend the money to have the local analytical lab test the product with IR spectroscopy or gas chromatography."
    Last edited by tillyfromparadise; 7th November 2013 at 04:52 PM.

  3. #3
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    Re: Making triacetin from glycerol

    Thank you for arranging the writing better. I probably can't pass university english class. Here they had "engineer's english" but I didn't take that either. You ever see one of those short women univeristy english teachers that try to ruin the large male students? I had one of those once. But I got along just fine with my chemistry professors. I figured on paper that about 30 milliliters of water was produced in the Fischer esterification of the 51.3 grams of glycerine with the reaction with glacial acetic acid. I found several recent patents dealing with this subject. It is a relatively new thing making glycerol triacetate from biodiesel byproduct. Thanks

  4. #4
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    Re: Making triacetin from glycerol

    On 5/17/13 poured 118 ml glycerine into a 1 litre round bottom boiling flask, added 289.3 ml glacial acetic acid. Swirled to mix the liquids. Next, poured 3.4 ml concentrated sulfuric acid into the flask without stirring. The sulfuric acid sank to the bottom of the flask. Initially the temperature of the reactants was about 20 degrees centigrade. About 1-2 minutes later, when I looked at the thermometer immersed in the reaction liquid the thermometer read 34 degrees centigrade. The reaction is exothermic. I read a news story that here in Chicago in the USA some chemical plant workers improperly added sulfuric acid to glycerine and the building blew up. This reaction should be done with caution if you decide to do it. Part of the proceedure is boiling acid in a container. Thanks

  5. #5
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    Re: Making triacetin from glycerol

    Seems like a long winded aproach to something I wouldn't use.
    What can it be used for and how many tonnes do you need to make before your Lab makes some money from it ?

    Good luck. I too had to re read it several times before I got the picture of how hard you had to work on the end product.
    But if you have a byproduct that you need to get rid of like we all do then maybe you are on to something really good.

    Again thanks for posting an imformative read, it is good to see someone trying for different solutions to our problems.

    Michael
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  6. #6
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    Re: Making triacetin from glycerol

    Reading the listing for "Glycerol Triacetate" on Wikipedia online gives a good description of what it can be used for.

    But, triacetin can be used as an antiknock agent in gasoline and to improve cold and viscosity properties of biodiesel.

    It also can be used as: a cigarette additive, for its humectant function, as a casting liquor, as an excipient in pharmaceutical products.

    I found online that glycerol triacetate 99%, 3 KG costs $102.95 on one site. Elsewhere a metric ton costs about $2000.

    When I requested information from the USA government about restrictions on making and selling perfume, they sent me about 100 pages of regulations related to the safety and purity of putting something on the skin of a person.

    Maybe there are similar restrictions on the purity of triacetin in Australia related to requirements of purity for use in pharmaceuticals. I haven't calculated how much it costs to make large quantities on a long term basis. That would involve buying barrels of glacial acetic acid. I just bought about 2.5 litres of glacial acetic acid 100.0%, for about $80. It uses an unwanted waste product to make something worth money.
    Last edited by Tim-HJ61; 8th November 2013 at 10:38 PM. Reason: Mod edit - Layout - PLEASE USE PARAGRAPHS

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