Study On Synthesis Of Waste Oil-based Polyol Esters

As a major consumer of edible oil,China produces up to 5 million tons of waste oil per year.The large amount of toxins and carcinogens contained in these waste oils are extremely harmful to the human body.At present,the synthetic process for producing biodiesel from waste oil is relatively mature.Biodiesel is a renewable resource,but biodiesel has a high synthetic cost and cannot completely replace petroleum diesel.The application has limitations,so this study will explore the further development and utilization of biodiesel and the implementation of the route.In this study,the waste oil is used as raw material,refined,and transesterified with methanol to form fatty acid methyl ester.Then,the transesterification reaction was carried out directly with the polyol represented by glycerin and starch under the action of a base catalyst.The monoglyceride and fatty acid starch ester were synthesized respectively,and the structure and properties of monoglyceride and starch ester were studied.(1)Preparation of fatty acid methyl esters using waste oil as raw material.The suitable reaction conditions were determined by orthogonal experiment: the molar ratio of alcohol to oil was 6:1,the amount of catalyst was 0.6w% of the mass of the oil,the reaction temperature was 63?,and the reaction time was 60 min.After the experiment,the biodiesel yield was 93.98%,and the purity was 99.97%.The structure was determined by FT-IR,and the components were analyzed by GC-MS,and the oil quality was tested to provide a basis for subsequent work.(2)Preparation of a monoglyceride using fatty acid methyl ester and glycerin as raw materials.The effect of reaction conditions on monoglyceride yield was investigated.The suitable reaction conditions were as follows: the molar ratio of fatty acid methyl ester to glycerol was 1:1,lithium hydroxide was used as catalyst,and the dosage was 0.5w% of the total amount of reactants.The reaction temperature was 185? and the reaction time was 4h.After the experiment,the monoglyceride yield was 91.56%.The HLB value and solubility were measured to determine that the monoglyceride was a water-in-oil surfactant.(3)The corn starch is amorphized,and then excess fatty acid methyl ester is added to prepare fatty acid starch ester.The effects of reaction conditions on DS of starch hydroxy groups were investigated.The suitable reaction conditions were as follows: the molar ratio of starch glucosyl unit to fatty acid methyl ester was 1:4,with lithium hydroxide as the main catalyst,and the mass fraction was 6w% of starch,p-toluenesulfonic acid as a cocatalyst,3w% of starch,the reaction temperature was 150? and the reaction time was 6h,the hydroxyl DS of fatty acid starch ester is 0.0611.The structure of product was characterized by FT-IR and XRD,the properties of starch esters such as viscosity,transparency,coagulation,hydrophilic lipophilicity and emulsifying properties were studied.