Research On Green Synthetic Process Of Bio-based Plasticizer

As an additive in polymers,plasticizers play an important function,mainly reducing the glass transition temperature(Tg)and changing their properties to make the material more flexible and ductile.Phthalate esters are plasticizers with the largest market share,but studies have found that they are potentially harmful to human health.Therefore,green and environmentally friendly biobased plasticizers have become a research focus.In this thesis,the green synthesis process of two bio-based plasticizers of 2,5-furandicarboxylate diisooctyl and isosorbide dicaprylate was developed,and a new plasticizer was designed and synthesized based on pentaerythritol.The plasticization performance test was carried out separately.This research constructed a green process for the synthesis of bio-based plasticizer 2,5-furandicarboxylate diisooctyl ester from biomass derivatives:Firstly,5-hydroxymethylfurfural oxidase HMFO and its mutant HMFO(V367R-W466F)was expressed in an E.coli expression system.The crude enzyme solution expressing enzyme activity was used to oxidize 5hydroxymethylfurfural(HMF),and the wild-type HMFO produced almost no 2,5-furandicarboxylic acid(FDCA).The mutant HMFO(V367R-W466F)mainly produced FDCA,and the concentration reached 267.72 mg/L after 5 hours of reaction.Then the green catalyst ionic liquid catalyzed the reaction of FDCA and isooctyl alcohol to produce 2,5-furandicarboxylic acid diisooctyl.The study found that 1-butanesulfonic acid-3-methylimidazole hydrogensulfate([BSO3HMIm][HSO4])has the best catalytic effect,and the optimal reaction conditions were as follows:the amount of ionic liquid was 5%(w/w),acid:alcohol=1:5(mol:mol),the reaction temperature was 140℃.The highest esterification rate reached 97.72%,and finally the product with a purity of 99.05%was obtained through separation and purification.This study used isosorbide and caprylic anhydride as substrates to synthesize isosorbide dicaprylate through ionic liquid.And 1-pentyl-3methylimidazole chloride salt([PnMIm]Cl)was selected as the ionic liquid with the best catalytic effect.And the optimal reaction conditions were as follows:the molar ratio of caprylic anhydride to isosorbide was 2.2:1,the reaction temperature was 100℃.Finally the relative content of diester was up to 52.60%,and the purity of product was 98.50%.This research has designed and synthesized a plasticizer with new structure-pentaerythritol tetra(furan-2-carboxylic acid)ester,which used the more active furoyl chloride to react with pentaerythritol.A preliminary smallscale study was conducted.Finally,a product with a purity of 98.12%was obtained,and the structure of the sample was identified.This research synthesized FDCA from biomass derivative HMF through enzyme catalysis.In this study,ionic liquid was selected as a catalyst to catalyze the synthesis of dioctyl 2,5-furandicarboxylate and developed a green environmental route for the synthesis of bio-based plasticizers from biomass derivatives.This research used ionic liquid to catalyze isosorbide and caprylic anhydride to synthesize isosorbide ester plasticizer.The amount of ionic liquid was small,only 0.5%of the mass of the substrate.Compared with previous studies,the reaction time was shortened by nearly 6 times,and the relative content of diester was increased by nearly 7%.In this study,a plasticizer with a new structure-pentaerythritol tetrakis(furan-2-carboxylic acid)ester was designed,and the test showed that it has good plasticizing properties.