I was using Calcium Oxide as catalyst, Jatropha oil as raw material. After 15hours, the result i got is this.. makes few times edi, but keep obtain the liquid on the top part.. and i mix with water, the top part will cause emulsion and residue at bottom layer.
Welcome to the forum.
My guess is that it is methanol on top of the oil.
I have never heard of using Calcium Oxide as catalyst.
Why did you use Calcium Oxide as catalyst?
If that is a result of a shake up test any excess methanol would be mixed with the water layer in which case it wouldn't be at the top and the bottom.
It looks more like emulsified monoglycerides at the bottom.
Did you do a conversion test at all.
Becoz my research by using waste material (clamshell) as source of CaO to produce biodiesel..
No.. i didnt, which means this is incomplete reaction or the catalyst is not good enough to favor the reaction?
I m very sceptical about using Cao to catalyse the reaction.
I have looked it up and apparently there has been some research on this but still...
Noone I have ever talked to has used the method.
Did you achieve any separation of glycerine to the bottom of the reactor during the initial reaction?
Erm.. i start from the acid pretreatment first by using H2SO4 and then proceed to CaO catalyst.
The glycerine i didnt bother it becoz since it juz byproduct.. does it affect the result?
The presence of glycerine is important to the total reaction.
I am trying to understand what you have done.
Please describe in great detail in stepwise manner what you did and what happened including things such as:
I understand you did an acid esterification as your first stage.
Did glycerine appear?
If it did appear, when did the glycerine appear, after the acid stage or after the Cao stage?
Did you remove the glycerine?
What did the oil originally titrate before the acid stage?
What did it titrate after the acid stage?
What amount of H2SO4 and methanol per litre of WVO did you use in the first stage.
Did you drain the "bottoms" after the acid stage?
ETCThis message has been edited. Last edited by: Tilly,
For the acid stage, only 0.25mL H2SO4 used and 16mL methanol in 50mL oil. After the reaction, i juz remove the methanol part and wash with hot water only and then proceed to the next stage.
Sorry for making trouble for you >_<
Tilly, Have a look at this ORIGINAL ARTICLE
Modification of egg shell and its application in biodiesel production.
Jim, what is the ORIGINAL ARTICLE?
Questions: 1) Without the original article it is difficult to understand some of the thinking.
For instance, acid pretreatment is only required when there are substantial free fatty acids which should not be the case for virgin jatropha oil, correct??
2) The neutralization of the sulfuric acid using calcium oxide should form calcium sulfate (CaH2SO4) which is practically insoluble in water, most certainly completely insoluble in methanol and most probably accounts for the white precipitate. For that matter CaO is white crystalline solid itself.
3) I don't have a really good explanation for the floating precipitate except you might imagine that some of the calcium sulfate has become coated with a film of oil and entrained air due to the shaking and so floats.
4) Is there any evidence that Calcium Oxide is a strong enough base to deprotonate methanol and form the calcium methoxide? In the case of sodium hydroxide the sodium hydroxide dissolves into the methanol by forming the Na cation (Na+) and hydroxide anion (-OH) then the hydroxide anion deprotonates the methanol to form water (HOH) and methoxide (-O-CH3) which proceeds to attack the triglyceride. What would be the mechanism by which the CaO would even dissolve in the methanol?
Just some questions.
Instead of -hydroxide (sodium, potassium), can i use carbonate as base catalyst? like sodium carbonate.. or other base else..
Performance of calcium oxide as a heterogeneous catalyst in biodiesel production: A review
The main drawback of using eggshells or mollusk shells is the huge amount of energy required to process that calcium carbonate into CaO. That's basically what a limestone kiln does to make cement.
The NaOH is not the expensive reagent, the methanol is.
Sorry Rick, I thought I had given the link to the article, John has picked it up. Jim.
Thanks, Tilly for your citation about the preparation of the catalyst. I couldn't access the article John referenced due to the lack of access. The article Tilly cites indicates that it is important to properly prepare the egg shell CaO in order to more than double the surface area of the catalyst and increase it's activity from 9.8 to 12.2-15. Even then it requires 5% by weight to get the 67% conversion. If a liter of oil weighs 950 grams then you need 50 grams per liter to get the 5%. That's 10-fold that required for NaOH.
And as you say the energy cost just to prepare the catalyst is substantial although we don't really know how much energy it takes to make NaOH or KOH.
Chin might take his CaO and heat it in a hot kitchen oven for a couple of hours to see if it improves performance. The thing with egg shell is that raw egg shells may be a combination of calcium hydroxides & calcium oxides intermixed with an organic matrix which when heated to high temperatures (600-900 degrees) loses the organic matrix leaving a high surface area active surface. This contrast with CaO powder which while it may have a relatively high surface area still consists of essentially solid particles with no interior active surfaces upon which to catalyse the reaction.
Just some thoughts.
i used the calcinated CaO and also calcinated clamshell but not working..
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