Jun Fu,Dezhang Ren,Lu Li,Yunjie Liu,Fangming Jin,Zhibao Huo
An efficient conversion of dimethyl phthalate (DMP) to phthalide (PHT) over CuO in aqueous media was investigated. Among the catalysts we tested, various metals or metal oxides were effective for the conversion of DMP to PHT in water, and CuO showed excellent catalytic activity and gave the best result. The PHT yield of 85% was achieved when Zn acted as a reductant. Mechanism study for the conversion of DMP suggested that an intermediate 2-hydroxymethyl benzoic acid was produced in the process. The present study provides a useful route for the production of PHT from DMP.
Xiaojie Shao,Peng Zhao,Zishang Tian,Ning Zhang,Hongliang Wang,Xuekuan Li,Xiaojing Cui,Xianglin Hou,Tiansheng Deng
ABSTRACT The continuous consumption of fossil resources and the resulting environmental pollution problems make the synthesis of polymers from renewable resources more and more attractive. Herein, a bio-based epoxy curing agent, 3,6-epoxide hexahydrophthalic anhydride (EHPA), was synthesized successfully from renewable furan and maleic anhydride by combining Diels-Alder and hydrogenation reactions and can cure diglycidyl ether of bisphenol A (DGEBA) to produce a sustainable thermosetting resin (EEP). Tensile properties and dynamic mechanical analysis show that EEP is a high-strength, high-toughness, and high-modulus material, showing higher glass transition temperature (201°C), tensile strength (104.51 MPa), and storage modulus (4.14 GPa) than those of epoxy thermosets (MEP) cured with the petroleum-based methyl tetrahydrophthalic anhydride (MeTHPA). Besides its high performance, EEP can be degraded via the cleavage of its ester bonds at mild conditions (150°C, 5 wt.% NaOH aqueous solution), making it an environmentally friendly alternative to petroleum-based epoxy resins. Our results provide a way to synthesize bio-based curing agents to fabricate high-performance and degradable epoxy resin polymers that are expected to be applied in the aerospace fields.
The solid–liquid equilibria (SLE) in the ternary system of 2-methyl-1,4-naphthoquinone (2-MNQ) + phthalic anhydride (PA) + 1,4-dioxane were determined experimentally by using the isothermal dissolution equilibriam method within temperatures 283.15, 293.15, and 303.15 K, respectively. The ternary phase diagram could be helpful in the separation of 2-MNQ and PA. On the basis of the experimental data on solubilities the phase diagrams of the system were plotted. Two pure solid phases were formed at 283.15, 293.15 and 303.15 K, including pure PA and pure 2-MNQ, which were confirmed and determined by Schreinemakers’ wet residue method. The phase diagram at 283.15 K is similar to those at 293.15 and 303.15 K and the crystalline regions of 2-MNQ and PA decrease with increasing temperature. NRTL and Wilson model were employed to correlate and calculate the solubility data for the ternary system. A comparison between the two models shows that the NRTL model agrees better with the experimental data than those with the Wilson model. In addition, the densities of equilibrium liquid phase were obtained at the corresponding temperatures versus composition in the system.
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