Bob, Good thing that isn't the route I will be taking with the IPA.
Andy On Fri, 14 Jan 2005 11:46:40 -0600, bob allen <[EMAIL PROTECTED]> wrote: > hello Kieth, Andy, et al, > > Why base catalyzed transesterifcation works well with Methanol but not > so well with most other alcohol. (another little chemistry lesson). > > Among common alkyl alcohols such as Methanol (MeOH) Ethanol (EtOH), > isopropanol (iPrOH) and higher homologs, only MeOH has a pKa lower > than water. > > MeOH 15.5 > HOH 15.7 > EtOH 16.0 > iPrOH 16.7 > > What this means is that when you mix NaOH or KOH with Methanol, > equilibrium favors formation of the Methoxide ion -OMe : > > MeOH + KOH --> K+ + - OMe + HOH > > but for the others the Hydroxide ion is favored: > > iPrOH + KOH <--- K+ + -OiPR + HOH > > Only when the right side of the equation is favored, is a > significant concentration of the alcoxide present. It is the alcoxide > which accomplishes transesterifcation. When the left side is favored, > significant hydroxide is present. Hydroxide causes significant > saponification. The left side of the equation is favored for all > alcohols whose pKa is higher than water. > > There are tricks to shift the equilibrium (Le Chatelier's Principle) but > it gets more difficult, expensive or both. > > > Keith Addison wrote: > > > Hello Andy > > > >> I am helping a friend setup a reactor and he has 4 55 gallon drums of > >> IPA. He has little time so it is slow going, but I will let you know > >> how it goes. Since the it has the higher boiling point we will run at > >> a higher temperatures. > >> > >> I am interested in trying the BIOX reaction as well but want to make > >> sure that the reactor is air tight first. > > > > > > :-) I'd suggest you check on whether the process is watertight before > > you start bothering about the reactor. (It ain't!) Rather thoroughly > > discussed here previously, a few times. I think calling it "the BIOX > > reaction" might be somethinbg of a misnomer, for one thing. > > > > See: > > > > http://infoarchive.net/sgroup/biofuel/35434/ > > > > http://infoarchive.net/sgroup/BIOFUEL/35449/ > > > > Check the links in those posts. > > > > Best wishes > > > > Keith > > > > > > > >> Andy > >> > >> > >> On Fri, 14 Jan 2005 09:12:26 -0300, Andres Yver <[EMAIL PROTECTED]> wrote: > >> > On Thursday, January 13, 2005, at 05:50 AM, Jan Warnqvist wrote: > >> > > >> > > Hello there ! > >> > > Is there anyone who has experience in isopropyl alcohol or its > >> esters > >> > > as fuel components ? > >> > > Jan Warnqvist > >> > > >> > > >> > Here's a pdf out of Iowa State University: > >> > > >> > www.me.iastate.edu/biodiesel/Technical%20Papers/Wang%20Intro.pdf > >> > > >> > The production of isopropyl esters and their effects on a diesel > >> engine > >> > > >> > "The scope of this research was to improve the cold weather properties > >> > of neat biodiesel > >> > by investigating the manufacture of isopropyl esters from soybean oil > >> > and yellow grease. > >> > Isopropyl esters have a lower crystallization temperature compared to > >> > methyl esters from the same source material." > >> > > >> > www.me.iastate.edu/biodiesel/Technical%20Papers/ > >> > Wang%20Equip%20Analysis%20Results.pdf > >> > > >> > Optimizing the Transesterification Process for Isopropyl Esters > >> > > >> > "Producing isopropyl esters requires the use of isopropyl alcohol as > >> > opposed to methyl > >> > esters, which utilize methanol, or ethyl esters, which use ethanol. > >> > Commonly, most biodiesel > >> > consists of methyl esters and methanol is used since it is cheap and > >> > widely available. > >> > Methanol is priced between $.04-.24/lb [14] and is the fourth largest > >> > organic chemical in the U.S. in terms of volume. Isopropanol, on the > >> > other hand, is priced between $.20 - .34/lb [14], which makes it more > >> > expensive to make isopropyl esters. However, the yield for isopropyl > >> > esters is about 10% more than methyl esters because of the heavier > >> > molecular weight. So, this partially compensates for the increased > >> > cost." > >> > > >> > hth, > >> > andres yver > > > > > > _______________________________________________ > > Biofuel mailing list > > [EMAIL PROTECTED] > > http://wwia.org/mailman/listinfo.cgi/biofuel > > > > Biofuel at Journey to Forever: > > http://journeytoforever.org/biofuel.html > > > > Biofuel archives at Infoarchive.net (searchable): > > http://infoarchive.net/sgroup/biofuel/ > > > > > -- > ------------------------------------------------------------------ > Bob Allen,http://ozarker.org/bob > ------------------------------------------------------------------ > ----------------------------------------------------------------- > The modern conservative is engaged in one of Man's oldest exercises > in moral philosophy; that is, the search for a superior moral > justification for selfishness JKG > -------------------------------------------------------------------- > > --- > [This E-mail scanned for viruses by Declude Virus] > > _______________________________________________ > Biofuel mailing list > [EMAIL PROTECTED] > http://wwia.org/mailman/listinfo.cgi/biofuel > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuel archives at Infoarchive.net (searchable): > http://infoarchive.net/sgroup/biofuel/ > _______________________________________________ Biofuel mailing list [EMAIL PROTECTED] http://wwia.org/mailman/listinfo.cgi/biofuel Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuel archives at Infoarchive.net (searchable): http://infoarchive.net/sgroup/biofuel/
