Efficient biofuel production by MTV-UiO-66 based catalysts

Two series of MTV-MOFs, MTV-UiO-66(COOH)2 and MTV-UiO-66(OH)2 are synthesized in a modulated synthesis approach yielding highly defected MTV-MOFs structures. Active sites are provided in the structure through the functionalized linkers, and the defected clusters. These active sites serve as the drive for the catalytic activity of the MTV-UiO-66 structures in the esterification reaction of butyric acid with butanol for butyl butyrate production. [Display omitted] •Two series of MTV-UiO-66 structures were synthesized and fully characterized.•Linkers were homogeneously incorporated in the framework in three different ratios.•The designed MTV-MOFs were employed as efficient catalysts for biofuel production.•A weighted linear regression model was used to predict the conversion rates. In this study, highly defected and functionalized metal-organic framework (MOF) structures are developed and exploited as catalysts for an esterification reaction for biofuel production. Two systems of multivariate UiO-66 series, namely MTV-UiO-66(COOH)2 and MTV-UiO-66(OH)2 incorporating dicarboxylate and dihydroxy groups, respectively, along with the single component structures, are thus explored for butyl butyrate production. Ratios of functionalized linkers to terephthalic acid are varied and a modulation synthesis approach is employed allowing for high levels of structural defects. The synthesized MOF structures are fully characterized using Powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), proton nuclear magnetic resonance (1H NMR), Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM), and the results confirmed the homogeneous incorporation of the functionalized linkers in the structures. The combination of multivariate approach along with modulation synthesis yields structures with catalytic activity higher than those of highly defective fully functionalized structures and close to the homogeneous conventional catalyst used in esterification reactions. Moreover, the ratio of functionalized linkers to terephthalic acid is shown to be very important since not all MTV-UiO-66 performed better than the single-component structure which can be attributed to a combination of factors related to the density of active sites and their accessibility. The most active MTV-UiO-66(OH)2 member, incorporating 52% of functionalized linkers, a defects number of 1.9, and a surface area of 761 m2/g, yielded 92% conversion to butyl butyrate, compared to 95% for H2SO4