Dear Christian, well first of all thank you very much for all the information, really good. To the Crest contact: The person in charge for further questions is :Allison White: [EMAIL PROTECTED] she is able to answer your questions about formal matters. Also a look onto the website might help: http://www.lboro.ac.uk/crest/MSC/index.htm As I know is there no possibility to get it funded, otherwise I would have tried it, but try it your own, it is perhaps worth.
So far. Much lick and the best. Regards, Andreas. -----Original Message----- From: William Clark [mailto:[EMAIL PROTECTED] Sent: 10 July 2002 01:13 To: biofuel@yahoogroups.com Subject: Re: [biofuel] (anhydrous) S.M. and glycerol protonisation, titration, Her is a link for MSDS on anhydrous S.M.. http://www.alkalimetals.com/MSDS/SODIUM%20METHOXIDE%20MSDS.htm Does anyone know anything about this substance? Bill C. ----- Original Message ----- From: "Christian" <[EMAIL PROTECTED]> To: <biofuel@yahoogroups.com> Sent: Tuesday, July 09, 2002 11:46 AM Subject: Re: [biofuel] (anhydrous) S.M. and glycerol protonisation, titration, > Hi Andreas. I doubt I«ll be able t answer all your questions but I«ll see if > I can help a bit. > > > > My name is Andreas Jansen, student for Environmental Management in > > The Netherlands, however since a year taking part at the MSc for > > Renewable Energy Systems Technology at Crest in Loughborough, UK. My > > dissertation started 4 weeks ago and is about the topic "biodiesel". > > Therefore I have to optimise a small-scale prototype installation > > running on used cooking oil for a company, which is just three years > > in business, not having much experience yet, which makes the work and > > support for me sometimes rather difficult. > > For this I read lot of abstracts, however my chemical background is > > not so very strong, still for some understanding sufficient. However > > there are some topics where I struggle with and cannot find an answer > > to: > > > > 1. When considering Sodium Hydroxide as catalyst for alkaline > > based transesterification I wonder about the following things: A > > reaction mechanism tells me, that the methanol and sodium hydroxide > > form S.M. and water. S.M. catalyses the transesterification and at > > the end the H+-ion from the previous formed water is deprotonated by > > the diglyceride-ion (or later mono-glyceride- or even later glycerol- > > ion) to form a fully alcohol group and finally glycerol. My concern > > is whether this combination of H+-ion and (di)glyceride-ion is > > necessary to occur or whether in the glycerol-layer after separation > > also (di)glyceride-ions may be found if not all (di)glyceride-ions > > have had combined with the H+-ions from the water? A catalyst should > > be found back at the end (if not saponified), that is what a catalyst > > defines, or? Therefore only glycerol but no (di)glyceride-ions should > > be found? > > Furthermore, if now assumed that anhydrous S.M. powder as catalyst is > > used, would that (under the assumption that H+-ions must react with a > > (di)glyceride-ions to form the glycerol) mean, that water must be > > deprotonated and if water is initially present in the oil this water > > would be removed, thus lowering the saponification reaction between > > f.f.a., water and Na+-ions?? That would be quite a benefit to > > consider buying S.M. powder instead of producing S.M. self by mixing > > Me-OH and NaOH! > > > > I was unaware of the fact you could buy dehydrated S.M. This would be a > great improvement, as it would reduce the ammount of water in the > transesterification. The term catalyst must be carefully used here. From > what I recover, the catalyst will be somewhat consumed hence disrupting its > own definition. Even more complex solid catalysts used in complex industries > (as pharmaceutical), often patented salts like Titanium tetraalcoxides and > so, will probably serve for 20 or so reactions. The end product may always > have rmains of mono- & di- glycerides, as 100% efficiency is not possible. > > > 2. When doing previous the reaction a titration to determine the > > degree of f.f.a. I take 1 ml oil and dissolve it in 10 ml iso- > > propanol. pH meter and litmus-pH-paper give different results during > > titration and the indicator (phenolphthalein) is not behaving like > > expected. It first tends only very, very light purple but remains > > like this, only if ~0,5 ml more NaOH solution is added (than at a pH > > of 10) it is turning totally purple. I thought a indicator colours or > > does not but the very light purple colour which stays and does not > > disappears after stirring more confuses me a lot? > > Concerning the difference in pH meter and paper I think to trust the > > meter, but if the oil is not dissolved good it might form a film > > around the measuring electrode and therefore diminishing the > > measurement? > > Right. Remember you still have a polar & non-polar mix (or rather an > emulsion). I used phenolpthalein and after the first supposed > neutralization, some more minutes of mixing turned it clear again. It«s a > hard-to-do titration. If you«re doing research for the company, maybe a gas > chromatogram would best analyse your oil and BD. that would answer your > qustions on mono- & di- glycerides, and your questions on FFA content. > > Might elevated T or adding more iso-propanol help in > > this case to prevent this film, without diminishing the reading in > > other respects? > > > > I think increasing temp is not adviseable here (I can«t remember well, but > something in my head sais it leads in those conditions to more degradation > of the oil and a higher FFA reading). Try thorough mixing and read the > result after a couple of minutes. > It might be useful (though a bit unorthhodox) to colour print a scale of 10 > pink marks, from light phenolphtalein pink to dark phenolpthalein pink. Then > you could maybe mark (for each volume of added base) the colour of the > solution after the initial addition, and its colour after 1, 3 and 7 > minutes. This is thinking out loud, but sometimes the changes in colour are > so suttle that a printed scale might help build a curve or something easier > to interpret your results. > I realised that at first, adding NaOH turned the solution pink and after > some minutes it turned back to transparent. But after some more additions, > it whent pink and then returned not to transparent, but to a very light > pink. This was past the correct titration ammount, so I had to redo the > experiment and take the readings for the "back to transparent" volume of > base. > > > 3. When doing the reaction I thought to add the S.M. and > > methanol already early when the T is still quite low while heating > > the reactor tank, rather than adding it only if the reaction heat is > > reached. That consideration just to save energy and time. However, > > when the ratio of saponification rate to the transesterification at > > lower T is higher than at higher T it should not be done to avoid too > > much soap formation. Could you give a short statement? > > > > Assuming you have used anhydrous methanol and dry oil, saponification will > occur due to the presence of NaOH and the water from the S.M. formation, > making the glycerides exchange their ast H for a Na (I know that«s not what > you asked). Now anhydrous S.M. would reduce soap formation. > Anyhow, I know people who have considered performing the reaction at room > temp for a longer period. I always thought that the equilibrium reaction > would take forever at that temp. However, this guy is a Chemical engineer, > and I he argued the reaction could be performed at room temp with good > yields. I don«t know if he somehow separated unracted oils and centrifuged > the S.M. to add it again in the mixture, thus retrieveing BD as it formed > (and pushing the reaction towards products side). > However I do not know the saponification & transesterification rates at > different temperatures. > > > > > > > > One personal question, if I might: > > I was looking for a funded PhD in the renewable energies field. I am a > recenly graduated environmental engineer, and an EEC member (French > passport). Do you know if the MSc for Renewable Energy Systems Technology at > Crest (Loughborough, UK.) is funded for EEC members? > > Could you help me finding out the entry requirements, maybe a course program > or at least the email of someone in charge of the addmitance for > environmental MSc & PH.D.s? > > I«d really appreciate that. > > Best wishes, > > Christian > > > > > > > > > > Biofuel at Journey to Forever: > > http://journeytoforever.org/biofuel.html > > > > Biofuels list archives: > > http://archive.nnytech.net/ > > > > Please do NOT send "unsubscribe" messages to the list address. > > To unsubscribe, send an email to: > > [EMAIL PROTECTED] > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > > > > > ____________________________________________________________________________ __ > mensaje enviado desde http://www.iespana.es > emails (pop)-paginas web (espacio ilimitado)-agenda-favoritos (bookmarks)-foros -Chat > > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://archive.nnytech.net/ > > Please do NOT send "unsubscribe" messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > Yahoo! Groups Sponsor ADVERTISEMENT Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. 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