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Esplosivo
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| Quote: |
2) Some specific condition is needed for the reaction to proceed (some gastric fluid maybe).
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In the intestine emulsifying agents are present to help facilitate the action of the enzyme, but these are not essential. Such emuslifying agents are
sodium taurocholate and sodium glycocholate. These are nothing but emulsifying agents, and therefore some form of neutal detergent which does not
denaturate the enzyme could be used in your case. This is just to help you in case you would like to try the process again.
Theory guides, experiment decides.
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Bio
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You might look at your temperature and try to regulate it at the pigs internal temperature. Some enzymes are heat sensitive as has already,
mentioned. 45 C maybe too hot. Human Brain proteins degrade above 105 F.
Just a thought I had.
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Esplosivo
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I mentioned the fact that the immobilised enzyme has a higher stability to temperature and can therefore operate very efficiently at a temperature of
45 deg celcius, therefore faster rates of reactions are obtained than with the 'free' enzyme. In fact the 'free' enzyme denatures
at such a temperature, and has an optimum temperature equal or similar to that of the internal body temp, i.e. approx 33 deg celcius.
Theory guides, experiment decides.
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Tacho
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I have exposed my mix to a wide range of temperatures (all below the denaturating temp. for the protein). NOTHING happen. Has anybody actually seen
lipase (or pancreatin) in action? What should I expect to see?
Should I contact the public health department and acuse the company of selling garbage?
Edit:
BTW,
CaOH does not work as catalyst, neither does sodium bissulfate, powdered zinc, urushibara nickel, oxalic acid nor caolin. Why caolin? I found
somewhere that certain clays would work as catalyst for this tranesterification, so, who knows, I could get lucky.
Damm. Sodium Bissulfate should have worked. It replaces sulfuric acid so many times...
[Edited on 29-9-2004 by Tacho]
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Bio
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Lipase will form a "sludge" that lies on the bottom or the top depending on the specific gravity. Some times there is a color somtimes
not.
ooops sorry about missing the temperature reference.
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robertd
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Diglycerides to biodiesel?..looking for help
Hello,
Pardon my lack of background/knowledge in chemistry. I have been working with transesterfying waste fryer oils into biodiesel, and having reasonable
success. Now I have found myself with access to quite a bit of by-product from a vegetable oil processing facility that I am wondering if it may be
applicable for biodiesel production.
Typically biodiesel is derived from triglycerides, converted via a reaction with a catalyst (typically sodium meth oxide), into methyl esters (with
glycerol as by product).
This by-product is primarily diglycerides.
Can diglycerides also be converted to methyl esters? If so, should I expect a substantial yield reduction?
Like I said, my chemistry background is minimal at best. My current yields are a function of free fatty acid content...the lower the ffa, the higher
the yield per catalyst (or the more catalyst required for reaction).
Any assistance would be greatly appreciated.
-Rob
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trilobite
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The transesterification proceeds stepwise
triglyceride + methanol --> diglyceride + fatty acid methyl ester
diglyceride + methanol --> monoglyceride + fatty acid methyl ester
monoglyceride + methanol --> glycerol + fatty acid methyl ester
It should make no difference if a diglyceride is used instead of a triglyceride. Yields will be lower in the sense that the fatty acid content of
diglycerides is lower compared to triglycerides, or in other words, more glycerol is produced per weight of the starting material and less methyl
ester.
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chemoleo
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I merged your questions into the existing thread.
This should answer your questions, and of course trilobite is correct in his answers
As to your yield - of course if the free fatty acid content is high, then this can't be transesterified with the existing methods, as you can
only transesterify the fatty acids that are already esterified to glycerol.
For the esterification of free fatty acids with methanol you need harsher conditions, than just methanol and catalytic amounts of sodium hydroxide.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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JohnWW
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In the case of triglyceride vegetable oils which are liquid at ordinary temperatures, and do not have to be melted to use, it should be possible to
use them unaltered as a substitute for diesel, without converting them to e.g. methyl esters by reaction with sodium ethoxide (which is relatively
costly to do, and poses the question of what to do with the glycerol). I believe this is already done.
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Tacho
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I’m attaching a wonderful work done by Adam Kahn about biodiesel’s chemistry. It’s very comprehensive.
I wonder why thermal cracking is not a more widely used method for producing fuels from triglycerides. The gas produced can fuel the cracking process,
the lighter fractions substitute gasoline, and the heavier fractions substitute diesel. It was used in large scale in china during some war.
Before someone points that the burning of the gas produce CO2, remember that producing and refining the alcohol for transesterification requires a lot
of energy. Thermal cracking also can use the most dirty and inpure triglyceride available.
Attachment: Adam_Khan_Thesis.pdf (425kB)
This file has been downloaded 2604 times
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chemoleo
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JohnWW, just in case you don't know, glycerol is a bulk product in the pharmaceutical/cosmetic industry. It certainly won't ever go to
waste. Industrially it is distilled off after fat hydrolysis.
Additionally, it's been mentioned before that just plain oils can be used for diesel motors etc- but this is clearly not applicable to more
sophisticated motors. Hence biodiesel.
The 'ethoxide' is not particularly costly, because all that is needed is (m)ethanol and NaOH as a catalyst. Both are bulk chemicals.
Nonetheless, of course this production scheme cannot, at this point, compete with the existing production of fossile fuels. Sadly.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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JohnWW
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Of course. Compared to use of raw liquid vegetable oils instead of diesel, production of liquid methyl or ethyl esters of the fatty acids requires at
least three reaction steps, which add to the costs: the synthesis of the methyl or ethyl alcohol e.g. by distillation of wood or from natural gas or
fermentation and distillation from simple carbohydrates, the production of the sodium methoxide or ethoxide by reaction with concentrated NaOH, and
then the use of this to convert the fatty acid triglycerides to methyl or ethyl esters.
As for the glycerol byproduct, while it has uses in pharmaceutical products and foodstuffs, and as antifreeze, if large amounts of biodiesel were ever
produced through diesel becoming unobtainable or too expensive, there could be a surplus of it beyond what the pharmaceuticals and foodstuffs etc.
industries can use.
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sathor
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Glycerol
hi, i know that in the saponification reaction glycerol is obtained but i don't know how to diference it and extract it...
and the amounts that i need to use
thanks
Edit by chemoleo: Are you still wondering how? SEARCH next time before you post!
[Edited on 24-2-2005 by chemoleo]
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Pyridinium
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| Quote: | Originally posted by Esplosivo
has an optimum temperature equal or similar to that of the internal body temp, i.e. approx 33 deg celcius. |
Am I missing something here? I believe the internal body temp is 37 C, and I think a normal pig's may even be high as 39.
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DDTea
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At my school, the shuttle buses all burn bio-diesel. It's funny because their exhaust is so dirty 
Off topic, but I figured it could be appreciated here.
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
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sparkgap
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Where I currently live, the price of one liter of gasoline is enough to buy three liters of Coca-Cola.  Good thing the government here is now researching into cost-effective alternatives for fossil fuels. Then again,
I'm still of the opinion that people should not own more than two motor vehicles...
Samosa: is the smoke black or brown? I'd tend to think their biodiesel was improperly processed...
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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Nerro
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Could there be a way to change some steps in the oxidative phosphorilation so that an excess of fatty acids is produced? and perhaps the bacteria
could produce the esters with ethanol they themselves form in anaerobic respiration too! that would be very interesting!
#261501 +(11351)- [X]
the \"bishop\" came to our church today
he was a fucken impostor
never once moved diagonally
courtesy of bash
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MadHatter
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Biodiesel
The university where I work is going over to a partial biodiesel substitute. We'll be
using an 80/20, diesel/biodiesel mix. There'll be some modifications to our vehicles.
The rubber hoses used in the fuel lines will be replaced with something on the order of
Viton.
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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joeflsts
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| Quote: | Originally posted by MadHatter
The university where I work is going over to a partial biodiesel substitute. We'll be
using an 80/20, diesel/biodiesel mix. There'll be some modifications to our vehicles.
The rubber hoses used in the fuel lines will be replaced with something on the order of
Viton. |
Our building maintenance manager has been using 100% bio for over two years. One time this winter he had to add some traditional diesel due to very
cold weather. He has determined that his cost per gallon is about $1.65.
Joe
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Nerro
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Biodiesel that solidified
Yesterday I've prepared my first ever batch of biodiesel by letting an excess of slightly alkaline (NaOH in EtOH) alcohol react with some vegetable
oil. I gave it a good shake in a glass stoppered bottle and then left it to stand for a while in the sun. When I checked back a few hours later there
was a nice separation between two obviously different layers, one slightly brown bottom layer of "biodiesel" and one layer of nicely transparant
glycerol. I seperated the layers using a sep. funnel and put the "biodiesel" in a jar to experiment with it later. But when I opened the jar today the
"biodiesel" had solidified completely into a gel that was not unlike vaseline in appearance but rather like "acidified waterglass" in the way it felt
and sort of crumbled when I pushed my finger into it. It dissolved very well in a little nafta but doesn't burn very well at all.
Does anyone have similar experiences with biodiesel? And would the results have been significantly different had I used MeOH in stead of EtOH? Did I
use the wrong kind of vegetable oil?
Any info on the subject would be greatly appreciated.
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The_Davster
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The bottom layer is glycerin, the upper is your biodiesel.
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Cloner
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Etoh is possible they say. Never did it myself though, and it should be more difficult to get it right. One of the problems is water. You definitely
want to use dry alcohol for transesterification.
The substance you have gotten likely contains soap.
[Edited on 7-5-2006 by Cloner]
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froot
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After succsessfully making biodiesel from methanol, I've been looking around for the ethanol method, ethanol being easier to make/acquire than
methanol this side of town. At the moment I'm looking for the possabilities/optimised method making ethanol from sugar and yeast with minimal water.
Here is a link I'm about to get stuck into.
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Of necessity, this honor is generally bestowed posthumously. - www.darwinawards.com |
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triphenylphosphineoxide
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| Quote: | Originally posted by MadHatter
The university where I work is going over to a partial biodiesel substitute. We'll be
using an 80/20, diesel/biodiesel mix. There'll be some modifications to our vehicles.
The rubber hoses used in the fuel lines will be replaced with something on the order of
Viton. |
Replacing fuel lines and fittings may be neccessary when burning ethyl-esters. Incomplete combustion(or hydrolysis if fuel is some how wetted) can
result in ethanol being formed. Ethanol is great for drying out rubber and its older substitutes, unfortunately cracked fuel lines are not fun.
Methanol is not as effiecient at destroying the fuel lines.
Although methanol is a wee bit harder to make and the methoxide vapours are more volatile, representing something of a hazard, The methyl esters are
the only way to go in older engines.
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kazaa81
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I've basified some ethanol with NaOH, then added 1/5 of volume of vegetable oil.
I've shaken until a somewhat like small droplets formed and the entire solution became of the same color.
But then, after 2 days, still nothing happened.
On the bottom there is a yellow layer, but it's still the oil I've added and, on the top there is still the basified ethanol.
My ethanol is common store buyed, dyed pink, quite pure, used for non-food purposes.
NaOH is technical grade 98-99%. The oil I've used I think it's not the bad thing in the reaction...it's olive oil.
Why does the reaction not happen? I don't see what's wrong.
Thanks
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