A spectroscopic study of calcium aluminate gels obtained from aluminium sec-butoxide chelated with ethyl acetoacetate in various ratios

4+ cages in which oxide anions are entrapped. Recent studies have revealed that the outstanding characteristics appear by exchanging the free oxide anions in the cages by various other anion species. In the present report, in order to enhance the oxidative catalytic activity of C12A7 by the encaged oxygen radicals, we synthesized C12A7 fine powders with high-specific surface area by solgel method and subsequent ball-milling. Aluminum secbutoxide, calcium nitrate tetrahydrate, absolute ethanol, 1 M hydrochloric acid, and ethyl 3-oxobutanate were used as raw materials. The obtained precursor solution was dried at 100°C for 24 h, and the product obtained was annealed at 900°C in O 2 atmosphere. Planetary ball milling was subsequently applied to the C12A7 powders. The XRD measurements revealed that the synthesized sample was a single phase C12A7. The BET specific surface area of the ground samples was 48.9 m 2 /g (24 h ground) and 17.3 m 2 /g (36 h ground) for those prepared by solgel method and by solid state reaction, respectively. The possibility was thus demonstrated on the synthesis of C12A7 fine powders with higher specific surface area by solgel method and subsequent planetary ball-milling.

show abstract

“…Aluminum sec-butoxide [Al(OBu s ) 3 14) Absolute ethanol was used as a solvent. 1 M hydrochloric acid (HCl, Kanto Chem.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of 12CaO 7Al2O3 powders with high specific surface area by sol-gel and ball-milling method

Ozawa

Sakamoto

Wakiya

et al. 2011

J. Ceram. Soc. Japan

View full text Add to dashboard Cite

show abstract

“…Butoxy groups are more susceptible to hydrolysis than acetoacetate groups, 11 but, judging by the presence of Ti-O-C stretching at 1125 cm -1 , and having in mind the established presence of alkoxy groups even in sample 0/1 (without the chelating agent), the fact that some of the alkoxy groups remained unhydrolyzed is definite. This is a consequence of efficient retardation of the hydrolysis-condensation process with the chelation agent, as well as mild experimental conditions since the hydrolysis was accomplished by exposing the samples to atmospheric moisture.…”

Section: Resultsmentioning

confidence: 99%

Sol-Gel Preparation of Nanocrystalline Titania Photocatalyst for Water Treatment Using N-Butoxide Modified With Ethyl Acetoacetate in Various Amounts

Kurajica¹,

Minga²,

Mužina³

2017

ECB

Self Cite

View full text Add to dashboard Cite

Sols prepared by chelation of titanium n-butoxide, Ti(OC4H9)4, with ethyl acetoacetate, C6H10O3, in various ratios were slowly hydrolyzed, and the obtained gels were investigated using Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The gels were thermally treated at 350 °C, and the products were investigated using X-ray diffraction, N2 gas adsorption-desorption isotherms and diffuse reflectance UV-Vis spectroscopy. Photocatalytic activity assessment was obtained through degradation process of methylene blue under UV light. From the results obtained, the relationships between gel structure and titania crystallite size, specific surface area, bandgap, and photocatalytic activity, as the most relevant parameters, were discussed. The alkoxide modification affected the gel structure, as well as the properties of the final material. However, the sample prepared from unmodified Ti-n-butoxide yielded the most favorable properties.

show abstract

“…Therefore, while the keto tautomer shows methylene protons signal at 3.45 ppm (K3), the enolic tautomer at this position has a single proton, whose signal appears at 4.8-5.1 ppm (E3). [10,22] In such manner the two tautomers are easy to discern and thereof it is clearly possible to monitor the extent of the chelation on behalf of the enolic-EAA content.…”

Section: Methodsmentioning

confidence: 99%

“…[9] EAA shows characteristic movement of weakly bonded hydrogen, thereof EAA resides in equilibrium between enol A and keto from, which is known as keto-enol tautomerism (Figure 1). [10] In the enolic tautomer a reactive hydroxy group, capable of becoming a bidentate monocharged enolate ligand is present and can substitute an alkoxy group in the metal alkoxide. As a consequence, a six membered chelate ring may be formed, consequently increasing the hydrolytic stability of the alkoxide (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, a six membered chelate ring may be formed, consequently increasing the hydrolytic stability of the alkoxide (Figure 1). [10] Normally, the keto-enol equilibrium heavily favours the keto form, yet the chelate formation will shift the keto-enol equilibrium towards the enolic form. [9,11] As for the sol-gel process, the main issue is the control of the hydrolysis and condensation processes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts

Kurajica

Mali

Mandić

et al. 2019

Croat. chem. acta (Online)

View full text Add to dashboard Cite

Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using β-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and β-ketoester or β-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.

show abstract

A spectroscopic study of calcium aluminate gels obtained from aluminium sec-butoxide chelated with ethyl acetoacetate in various ratios

Cited by 18 publications

References 29 publications

Fabrication of 12CaO 7Al2O3 powders with high specific surface area by sol-gel and ball-milling method

Fabrication of 12CaO 7Al2O3 powders with high specific surface area by sol-gel and ball-milling method

Sol-Gel Preparation of Nanocrystalline Titania Photocatalyst for Water Treatment Using N-Butoxide Modified With Ethyl Acetoacetate in Various Amounts

Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts

Contact Info

Product

Resources

About