I have not been able to get rational values for "P" (the mole per cent sorbitol) by inputting the numerical values on the right side of the equation. For example, Lf for Sorbitol is ≈ 1.353 J/mol (or ≈ 0.001775 cal/g , etc.); R is 8.31447 J/K/mol ; To is ≈ 370.15 K (or ≈ 97 C); Tf is ≈ 306.15 °K (or ≈ 33 °C) when mixed with choline chloride; M is 182.17 g / mol.
Walter C. McCrone (1957), [Interscience Publishers, Inc., NY] provides the attached equation (from page 157) as better than his more simple equation he shows on page 156.
Help with this problem could speed our development of more durable dental composite restorative materials in comparison with current materials, which we invented many years ago.