Ti(IV) doping: An effective strategy to boost Lewis acidic performance of ZnO catalyst in fluorescein dye synthesis

Heterogeneously Catalyzed Pechmann Condensation Employing the Tailored Zn0.925Ti0.075O NPs: Synthesis of Coumarin

“…The reaction pathway for the synthesis of coumarin through Pechmann condensation is represented in Scheme 1, and the mechanism for the reaction is assumed to be the same as proposed by using Zn 0.925 Ti 0.075 O NPs as a Lewis acid. 40 Initially, reaction proceeds with the nucleophilic attack of the hydroxyl group of phloroglucinol on the activated EAA, resulting in the formation of the intermediate and byproduct ethanol. The formed intermediate rapidly undergoes cyclization through Lewis acid-catalyzed intramolecular condensation and followed by dehydration which yields 5,7-dihydroxy-4-methyl-2 H -chromen-2-one.…”

“…We have reported the catalyst Zn 1– x Ti x O NPs for the synthesis of fluorescein via the Friedel-craft’s acylation approach. 40 The textural properties of Zn 1– x Ti x O NPs show high surface area and Lewis acidity characterized by Brunauer–Emmett–Teller surface area measurements and pyridine Fourier transform infrared spectra. Further, roughly spherical morphology of Zn 1– x Ti x O NPs was confirmed by scanning electron microscopy.…”

TiO2–ZnO composites fabricated via sonication assisted with gelatin for potential use in Rhodamine B degradation

“…The crystallite size for ZnO wurtzite was estimated taking the most intense peak (101), while the peak (110) was used for the TiO2 rutile phase. The crystallite size of the wurtzite ZnO (D(w)) exhibits a decrease with the addition of more TiO2 [30], while a reverse trend is shown by the rutile phase crystallite size (D*(R)). From the XRD findings, a successful synthesis of nanocomposites comprising of rutile TiO2 and wurtzite ZnO can be confirmed.…”

Insight on TiO2-ZnO Photocomposite Competence Fabricated via Sonication Assisted with Gelatin for Rhodamine B Degradation

“…The crystallite size for ZnO wurtzite was estimated taking the most intense peak (101), while the peak (110) was used for the TiO2 rutile phase. The crystallite size of the wurtzite ZnO (D(w)) exhibits a decrease with the addition of more TiO2 [30], while a The micro-strain is estimated via the expression [31] and the stress σ(GPa) in the crystallite's plane [32] are computed 5) (6where c and cbulk are the measured lattice parameter and the strain-free lattice parameter of ZnO (5.2061 Å) respectively. The Zn -O bond length (L) was calculated using the equation: 7where The tabulated values (Table 1) of the d-spacing, a, c, V and L reveal a decrease with the increment of titanium in the nanocomposites.…”

“…The Zn -O bond length (L) was calculated using the equation: 7where The tabulated values (Table 1) of the d-spacing, a, c, V and L reveal a decrease with the increment of titanium in the nanocomposites. This may attributed to the substitution of larger radius Zn 2+ (74 pm) by the smaller radius Ti 4+ (68 pm) [30]. The stress (ϭ) in the nanocomposites can be estimated by the strain model ϭ (Gpa) = -233*(c0c)/c0, where c and c0 are the lattice constants calculated from XRD data the lattice constant of the pure ZnO (0.5206 nm) respectively [33].…”