Stearic Acid → Palmitic Acid

Participants

Reaction Steps

Fatty acid methyl esters were tested for cold temperature performance as detailed above. The chart below shows the effect of adding long chain saturated fatty acids to C18:1 methyl ester (methyl octadecenoate). Pure C18:1 methyl ester is liquid at −20° C. but addition of C18:0 methyl octadecanoate) raises the observed pour point to as high as +5° C. with as little as 2% C18:0 present in the mixture; at 1% C18:0 the pour point of the mixture is 0° C. Similarly, C16 mixtures with C18:1 dramatically raises the pour point. A mixture of 9% (v/v) C16 methyl ester (methyl hexadecanoate) with 91% C18:1 was solid at −5° C. As little as 3% C16:0 resulted in a solid at −15° C. C14:0 methyl ester (methyl tetradecanoate) at concentrations as low as 1% resulted in a solid at −20° C., and 30% C14:0 was solid at −10° C. Mixtures with C12:0 (methyl dodecanoate) presented an interesting and unexpected result. At levels of C12 between 1% and 5% the mixtures were solid at −20° C., but between 6% and 20% C12 mixtures with C18:1 remained liquid at −20° C. Accordingly, the presence of C12:0 in a biodiesel at 6-20%; or more preferably at 6-10%, has surprising beneficial effects on cold flow properties. Thus, while the longer chain saturated FAMEs significantly raised the pour point of mixtures with C18:1, C14 had a much smaller effect and C12 had almost no effect at concentrations up to 20% (v/v).

Provenance & Evidence