Synthesis And Properties Of Epoxidized Propylene Glycol Monoesters Of Corn Oil Fatty Acids

Volatile organic compounds (VOCs) are one of the biggest problems facing the coatings and paint industry. Particularly, in waterborne coatings, one of the biggest sources of VOCs emissions is the film forming assistant. Therefore, development of VOC-free latex paint coalescing agents have been paid a great attention. In this wok, the preparation of corn methyl esters, synthesis and epoxidation of propylene glycol monoesters of corn oil fatty acids and the properties as a latex paint coalescing agent were studied.Corn methyl esters were prepared firstly with corn oil and methanol as raw materials and sodium hydroxide as a catalyst. The influences of the molar ratios of the raw materials, reaction time, catalyst amount and reaction temperature on the yield of the products were studied. The experimental results showed that the yield of the corn methyl esters could reach 95.6 % when the reaction temperature was 60 oC, the reaction time was 1h, the molar ratio of methanol to corn oil was 6:1, and the amount of catalyst was 1.0 wt. % of the corn oil.Propylene glycol monoesters of the corn oil fatty acids were synthesized by transesterifying corn methyl esters obtained from the first step with 1, 2-propanediol in the presence of zinc acetate. Structure of the product was characterized with IR and MS. The effects of the reaction temperature, reaction time, molar ratios of the raw materials and the catalyst amount on the reaction were studied. The experimental results showed that the yield of propylene glycol monoesters of corn oil fatty acids could reach 97.5 % when the reaction temperature was within the range of 180 oC -190 oC, the reaction time was 1h, the molar ratio of 1, 2-propanediol to corn methyl esters was 3:1, and the amount of catalyst was 0.20 wt. % of the corn methyl esters.The epoxidation of the propylene glycol monoesters of the corn oil fatty acids was investigated. The density, viscosity and iodine value of the synthesized products were measured and the film forming properties were studied. The results showed that the product with density of 0.93 g/cm3, viscosity of 33.5 mPa?s, iodine value of 90.8 iodine/100g has favorable film forming properties.