Polyols from triglycerides

For the purposes of making polyols from these triglycerides, oils which contain a high level of unsaturation are desirable. Oils such as soy, canola, and sunflower are acceptable due to relatively low levels of saturated fatty acids, while feedstocks such as palm oil are considered unusable without further purification or refinement due to high levels of saturated fatty acids. Table 1 outlines the composition of several oils (3). 

Petrovic, Z.S. W. Zhang I. Javni. Structure and properties of polyurethanes prepared from triglyceride polyols by ozonolysis. Biomacromolecules 2005b, 6, 713—719. 

PetrovicZS, Zhang W, Javni I. 2005. Structure and Properties of Polyurethanes Prepared from Triglyceride Polyols by Ozonolysis. Biomacromolecules 6(2) 713-719. 

Ideally, two moles of polyol react with one mole of triglyceride to form three moles of monoester. In reaUty, the reaction reaches an equiUbrium, whereby some amount of di- and tri-esters and neat polyol, including glycerol and the added polyol, coexist in the reaction mixture. The compositions of the alcoholysis products at equiUbrium from soya oil and glycerol (1 2 mole ratio), and soya oil and monopentaerythritol have been reported (33) as follows ... 

Thus, glycerol, the most important starter for the synthesis of polyether polyols for flexible PU foams and for polyether for rigid foams is produced by the hydrolysis of natural triglycerides (esters of glycerol with fatty acids with C6 to C22 carbon atoms), from vegetable or animal resources (reaction 17.1) [1]. Large quantities of glycerol appear in bio-diesel production, by transesterification of natural oils with methanol. 

Alkyds are made with oil contents varying from 30 to 80%. It is more accurate to refer to fatty acid content rather than oil content because the oil has ceased to exist as such after it has been reacted into the alkyd. It has been suggested that the fatty acids in 100 parts of theoretically completely esterified alkyd be calculated to triglyceride and used to define (in percent) the "oil length" or extent of oil modification. This method is of questionable value because the advent of new polyols and the increasing use of mixtures of the same to achieve special properties make it quite impossible to calculate the quantity of fatty acid ester. 

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