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MOF-5 (metal-organic frameworks-5) have been synthesized using solvothermal method in which reaction mixtures of zinc nitrate hexahydrate and 1,4-benzenedicarboxylic acid (BDC) in dimethylformamide (DMF) were heated at various heating temperatures and times in order to observe the influence of heating temperature and time on crystallinity and morphology of the obtained MOF-5. The heating temperatures used were 105, 120 and 140 °C, respectively with heating times of 12–144 h. Determination of the best reaction conditionswas based on the observation of phase purity and crystal morphology of MOF-5 using XRD and SEM. The characterization results showed that MOF-5 crystals with a higher crystallinity were obtained when the reaction mixtures were heated at 105 °C for 144 h, 120 °C for 24 h or 140 °C for 12 h. The maximum weight of MOF-5 crystal was generated from reaction mixture heated at 120 °C for 72 h.

UiO-66 solids have been synthesized using solvothermal method in which reaction mixtures of zirconium tetrachloride (ZrCl 4) and 1,4-benzenedicarboxylic acid (BDC) in N-N'-dimethylformamide (DMF) were heated at 140 °C for 6, 12, 24, 36, 48, 72 and 144 hours, respectively. The weight of reaction products, in the form white powder, increased with the increase in heating time up to 72 hours, then decreased. Characterization results using XRD showed that the diffractogram of the solid obtained at heating time of 6 h had the same pattern to that of reported UiO-66, characterized by a main peak with a high intensity at 2θ of 7.3°, as well as other characteristic peaks with lower intensity at 2θ of 8.4°; 25.6° and 30.6°. The longer the heating time (12 and 24 h), the lower the intensity of the main peak. When the reaction mixtures were heated for 36 h or longer, the obtained solid diffractograms showed that the main peak intensity at 2θ of 7.3° was lower than the second peak, and new peaks appeared at 2θ of 13.8°; 15.8° and 17.5°. SEM micrographs showed that the solid synthesized for 6 h was in the form of clusters of square morphology, whereas solids synthesized for 72 h showed needle-like surface morphology.

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