Synthesis Of Rosin-Sucrose Ester With Solvent-free Method

With the growth of the world's energy demand, petrochemical materials are inshort supply and the prices are rising. Coupled with the enhanced of environmentalawareness, surfactants industry will move toward renewable natural chemicals andnew materials with low prices. Rosin and sugar are abundant renewable resources inChina, and both of them are easily biodegradable. The three-ring phenanthrene skeleton in molecules of rosin is hydrophilic and hydrophilic groups can be introducedthrough the carboxyl groups in the resin acids of rosin, so rosin can be used as rawmaterial to synthesize surfactants. Sucrose is polyol with excellent hydrophilic ability.Therefore, nonionic surfactants can be prepared from rosin and sucrose ifesterification can take place between rosin and sucrose under some conditions. Thesynthesis of modified rosin sucrose esters meets the need of green chemistry andsustainable development.Hydrogenated rosin is a dominant varieties of modified rosin with good antioxygenic activity. In order to provide an intermediate used in synthesizing hydrogenated rosin sucrose esters, hydrogenated rosin methyl esters were prepared byesterification of hydrogenated rosin with (DMF)₂ (CH₃)₂ SO₄. The optimum conditions were found by orthogonal test as follows: reaction temperature 45℃, reactiontime is 3 h, n_DMF:n_LiOH:n_{Dimethyl sulfate}:n_{Hydrogenated rosin}=12.2:1.1:1.2:1. The esterified rateamounted to 92.1% under the above optimum conditions. Meanwhile, the exchangechromatography was used to purify the prepared crude hydrogenated rosin methylesters by the removal of the unreacted resin acids in the hydrogenated rosin. Themolecular structures in the hydrogenated rosin methyl esters were not changed afterthe column chromatography, The product was characterized by IR. GC detectionshowed that there was no detectable residues dimethyl sulfate in the product, so therefined hydrogenated rosin methyl esters can be used as the intermediate tosynthesize.Hydrogenated rosin sucrose esters were synthesized by transesterificationreaction of the hydrogenated rosin methyl esters with sucrose under solvent-free condition, in the presence of soap as emulsifier and K₂CO₃ as catalyst. Some influence factors such as reaction temperature, usage of emulsifier, reaction pressure andusage of catalyst were investigated. The target product was analyzed and characterizedby TLC, IR methods. The analysis result showed that hydrogenated rosin sucrosemono-ester is the main ingredients of the target product. Product has good emulsifying capacity, CMC=0.8×10^-2mol/L, corresponding surfacetension is45.0mN/m, thecloud point is not observed. The product has excellent compatibility with non-ionicsurfactant and anionic surfactant. That hydrogenated rosin sucrose esters havesatisfying surface activity.