Study on Production of High-monoester Sucrose Fatty Acid Esters by Improved Metallic Salt Method and Alcoholic Separation

Abstract Crude sucrose fatty acid esters made by solvent-free process are purified by an improved metallic salt method and alcoholic separation. It is found that purified sucrose fatty acid esters can be obtained only by the use of calcium chloride in an amount stoichiometrically equivalent to the amount of the potassium stearate to be removed or in a slight excess amount. Among other soaps, potassium stearate is removed more easily from the crude sucrose fatty acid esters, which shows that potassium stearate is the most suitable soap for the solvent-free synthesis of sucrose fatty acid esters. In addition, it is also found that pure sucrose fatty acid esters can be quantitatively separated into two fractions, one with high-monoester content, and the other with low-monoester content. Sucrose fatty acid esters with a wide range of HLB can be obtained by mixing the two parts in varied proportions. An equilibrium relationship between the distribution of sucrose fatty acid esters with a high HLB in liquid phase and sucrose esters with a low HLB in the precipitate is studied and a triangle graph and equations are given. According to the triangular graph and the equations, the yield of the two fractions can be predicted.