Aluminium ethoxide

Aluminium triethoxide (also aluminium ethoxide) is an metallo-organic compound with the empirical formula Al(OC₂H₅)₃. It is a moisture-sensitive white powder.^[2]

Aluminium ethoxide

Names
Other names Aluminium ethoxide Triethoxyaluminum
Identifiers
CAS Number	555-75-9^Y
3D model (JSmol)	Interactive image
ChemSpider	21171290
ECHA InfoCard	100.008.279
PubChem CID	16685041
UNII	S34F5V33DX^Y
CompTox Dashboard (EPA)	DTXSID7027203
InChI InChI=1S/3C2H5O.Al/c3*1-2-3;/h3*2H2,1H3;/q3*-1;+3 Key: JPUHCPXFQIXLMW-UHFFFAOYSA-N InChI=1/3C2H5O.Al/c3*1-2-3;/h3*2H2,1H3;/q3*-1;+3/rC6H15AlO3/c1-4-8-7(9-5-2)10-6-3/h4-6H2,1-3H3 Key: JPUHCPXFQIXLMW-MHHMYNCNAZ
SMILES CCO[Al](OCC)OCC
Properties
Chemical formula	C6H15AlO3
Molar mass	162.165 g·mol^−1
Appearance	White powder
Density	1.142 g/cm^3
Melting point	140 °C (284 °F; 413 K)
Boiling point	320 °C (608 °F; 593 K)
Solubility in water	reacts violently
Solubility	slightly soluble in xylene, chlorobenzene
Hazards
GHS labelling:
Pictograms	^[1]
Signal word	Danger^[1]
Hazard statements	H228, H314^[1]
Precautionary statements	P210, P280, P305+P351+P338, P310^[1]
Flash point	210 °C (410 °F; 483 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Properties

 

Structure of aluminium isopropoxide indicates the tendency of aluminium alkoxides to form aggregates.

Aluminium triethoxide is slightly soluble in hot dimethyl benzene, chlorobenzene and other high boiling point non-polar solvents.^[3] It hydrolyzes to aluminium hydroxide and ethanol:

Al(OEt)₃ + 3 H₂O → Al(OH)₃ + 3 HOEt

Although the structure of aluminium triethoxide has not been established by X-ray crystallography, the related aluminium isopropoxide has a tetrameric structure as verified by NMR spectroscopy and X-ray crystallography. The species is described by the formula Al[(μ-O-i-Pr)₂Al(O-i-Pr)₂]₃.^[4][5] The unique central Al is octahedral, and three other Al centers adopt tetrahedral geometry. A

Applications

Aluminium triethoxide is used as a reducing agent for aldehydes and ketones, and is also used as a polymerization catalyst. Aluminium triethoxide is mainly used in Sol-Gel Process preparation of high purity aluminium sesquioxide, which is a polymerization agent. At the same time, it is used as a reducing reagent, for example, carbonyl compounds that restore to alcohol.^{[clarification needed]}

Synthesis

Aluminium triethoxide is produced by treating an aluminium amalgam with anhydrous alcohol. The aluminium is often activated with iodine or by amalgamation to accelerate the reaction.^[6][2]

Aluminium triethoxide has been evaluated as a catalyst for the synthesis of esters and carbonates.^[7]

References

1. "Aluminum Ethoxide". American Elements. Retrieved 2019-07-15.
2. H. J. Becher (1963). "Aluminum Ethoxide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 834.
3. "Aluminium ethoxide". The Merck Index. Royal Society of Chemistry.
4. Folting, K.; Streib, W. E.; Caulton, K. G.; Poncelet, O.; Hubert-Pfalzgraf, L. G. (1991). "Characterization of aluminum isopropoxide and aluminosiloxanes". Polyhedron. 10 (14): 1639–46. doi:10.1016/S0277-5387(00)83775-4.
5. Turova, N. Y.; Kozunov, V. A.; Yanovskii, A. I.; Bokii, N. G.; Struchkov, Yu T.; Tarnopolskii, B. L. (1979). "Physico-chemical and structural investigation of aluminium isopropoxide." J. Inorg. Nucl. Chem. 41(1): 5-11, doi:10.1016/0022-1902(79)80384-X.
6. Wilhoit, R. C.; Burton, J. R.; Kuo, Fu-tien; Huang, Sui-Rong; Viquesnel, A. (1 December 1962). "Properties of aluminium ethoxide". Journal of Inorganic and Nuclear Chemistry. 24 (7): 851–861. doi:10.1016/0022-1902(62)80106-7. ISSN 0022-1902.
7. North, Michael; Young, Carl (2 November 2011). "Reducing the Cost of Production of Bimetallic Aluminium Catalysts for the Synthesis of Cyclic Carbonates". ChemSusChem. 4 (11): 1685–1693. doi:10.1002/cssc.201100239. PMID 22045591.