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Diethylaluminium chloride

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Diethylaluminium chloride
Structural formula of diethylaluminium chloride
Names
IUPAC name Chlorodiethylalumane
Other names Chlorodiethylaluminium
Identifiers
CAS Number
3D model (JSmol)
Beilstein Reference 4123259
ChemSpider
ECHA InfoCard 100.002.253 Edit this at Wikidata
EC Number
  • 202-477-2
PubChem CID
RTECS number
  • BD0558000
UNII
UN number 3394
CompTox Dashboard (EPA)
InChI
  • InChI=1S/2C2H5.Al.ClH/c2*1-2;;/h2*1H2,2H3;;1H/q;;+1;/p-1Key: YNLAOSYQHBDIKW-UHFFFAOYSA-M
SMILES
  • CC(Cl)CC
Properties
Chemical formula C8H20Al2Cl2
Molar mass 241.11 g·mol
Appearance Colorless liquid
Density 0.96 g/cm
Melting point −74 °C (−101 °F; 199 K)
Boiling point 125 to 126 °C (257 to 259 °F; 398 to 399 K) at 50 mmHg
Solubility in water Reacts
Vapor pressure 3 mmHg (at 60 °C)
Hazards
GHS labelling:
Pictograms GHS02: FlammableGHS05: Corrosive
Signal word Danger
Hazard statements H225, H250, H260, H261, H314
Precautionary statements P210, P222, P223, P231+P232, P233, P240, P241, P242, P243, P260, P264, P280, P301+P330+P331, P302+P334, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P335+P334, P363, P370+P378, P402+P404, P403+P235, P405, P422, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3 4 2W
Flash point −18 °C (0 °F; 255 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references
Chemical compound

Diethylaluminium chloride, abbreviated DEAC, is an organoaluminium compound. Although often given the chemical formula (C2H5)2AlCl, it exists as a dimer, 2 It is a precursor to Ziegler-Natta catalysts employed for the production of polyolefins. The compound is also a Lewis acid, useful in organic synthesis. The compound is a colorless waxy solid, but is usually handled as a solution in hydrocarbon solvents. It is highly reactive, even pyrophoric.

Structure and bonding

Compounds of the empirical formula AlR2Cl (R = alkyl, aryl) usually exist as dimers with the formula (R2Al)2(μ-Cl)2. The bridging ligands (indicated by "μ-") are halides, not the organic substituents. The aluminium adopts a tetrahedral geometry. Each Al(III) center follows the octet rule. In contrast, triethylaluminium and trimethylaluminium feature bridging alkyl groups and these compounds violate the octet rule.

Production

Diethylaluminium chloride can be produced from ethylaluminium sesquichloride, (C2H5)3Al2Cl3, by reduction with sodium:

2 (C2H5)3Al2Cl3 + 3 Na → 3 (C2H5)2AlCl + Al + 3 NaCl

It is also obtained from the reaction of triethylaluminium with hydrochloric acid:

(C2H5)3Al + HCl → (C2H5)2AlCl + C2H6

Reproportionation reactions can also be used:

2 (C2H5)3Al + AlCl3 → 3 (C2H5)2AlCl
(C2H5)3Al2Cl3 + (C2H5)3Al → 3 (C2H5)2AlCl

Uses

Diethylaluminium chloride and other organoaluminium compounds are used in combination with transition metal compounds as Ziegler–Natta catalysts for the polymerization of various alkenes.

As a Lewis acid, diethylaluminium chloride also has uses in organic synthesis. For example, it is used to catalyze the Diels–Alder and ene reactions. Alternatively, it can react as a nucleophile or a proton scavenger.

Safety

Diethylaluminium chloride is not only flammable but pyrophoric.

References

  • Hu, Y. J.; Jiang, H. L.; Wang, H. H., "Preparation of highly branched polyethylene with acenaphthenediimine nickel chloride/diethylaluminum chloride catalyst". Chinese Journal of Polymer Science 2006, 24 (5), 483–488.
  • Yao, Y. M.; Qi, G. Z.; Shen, Q.; Hu, J. Y.; Lin, Y. H., "Reactivity and structural characterization of divalent samarium aryloxide with diethylaluminum chloride". Chinese Science Bulletin 2003, 48 (20), 2164–2167.
  1. ^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 4–40. ISBN 978-1138561632.
  2. ^ Snider, Barry B. (2001). "Diethylaluminum Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd165. ISBN 0-471-93623-5.
  3. Brendhaugen, Kristen; Haaland, Arne; Novak, David P.; Østvold, Terje; Bjørseth, Alf; Powell, D. L. (1974). "The Molecular Structure of Dimethylaluminium Chloride Dimer, [(CH3)2AlCl]2 Redetermined by Gas Phase Electron Diffraction". Acta Chemica Scandinavica. 28a: 45–47. doi:10.3891/acta.chem.scand.28a-0045.
  4. McMahon, C. Niamh; Francis, Julie A.; Barron, Andrew R. (1997). "Molecular Atructure of 2". Journal of Chemical Crystallography. 27 (3): 191–194. doi:10.1007/BF02575988. S2CID 195242291.
  5. Krause, Michael J.; Orlandi, Frank; Saurage, Alfred T.; Zietz, Joseph R. (2000), "Aluminum Compounds, Organic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, pp. 592–593, doi:10.1002/14356007.a01_543, ISBN 978-3-527-30673-2
  6. Fisch, A. G. (2000). "Ziegler–Natta Catalysts". Kirk-Othmer Encyclopedia of Chemical Technology. Wiley. pp. 1–22. doi:10.1002/0471238961.2609050703050303.a01.pub2. ISBN 978-0-471-48494-3. S2CID 213111515.

External links

Aluminium compounds
Al(I)
Organoaluminium(I) compoundsAl(C5(CH3)5)
Al(II)
Al(III)
Alums
Organoaluminium(III) compounds
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