Diethylaluminium chloride

Diethylaluminium chloride, abbreviated DEAC, is an organoaluminium compound. Although usually given the chemical formula (C2H5)2AlCl, it exists as a dimer, [(C2H5)2AlCl]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.[2]

Diethylaluminium chloride
Structural formula of diethylaluminium chloride
Names
IUPAC name
Chlorodiethylalumane
Other names
Chlorodiethylaluminium
Identifiers
3D model (JSmol)
4123259
ChemSpider
ECHA InfoCard 100.002.253
EC Number
  • 202-477-2
RTECS number
  • BD0558000
UNII
UN number 3394
  • InChI=1S/2C2H5.Al.ClH/c2*1-2;;/h2*1H2,2H3;;1H/q;;+1;/p-1 checkY
    Key: YNLAOSYQHBDIKW-UHFFFAOYSA-M checkY
  • CC[Al](Cl)CC
Properties
C4H10AlCl
Molar mass 120.56 g·mol−1
Appearance Colorless liquid[1]
Density 0.96 g/cm3[1]
Melting point −74 °C (−101 °F; 199 K)[1]
Boiling point 125 to 126 °C (257 to 259 °F; 398 to 399 K) at 50 mmHg
Reacts[1]
Vapor pressure 3 mmHg (at 60 °C)
Hazards
GHS labelling:
GHS02: FlammableGHS05: Corrosive
Danger
H225, H250, H260, H261, H314
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 diamond
3
4
2
W
Flash point −18 °C (0 °F; 255 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Structure

Compounds of the empirical formula AlR2Cl (R = alkyl, aryl) exist as dimers with the formula (R2Al)2(μ-Cl)2. The aluminium adopts a tetrahedral geometry.[3][4]

Production

Diethylaluminium chloride can be produced from ethylaluminium sesquichloride, (C2H5)3Al2Cl3, by reduction with sodium:[5]

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.[6]

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.[2]

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.; Ramazanov, Ilfir R.; Dzhemilev, Usein M. (2009). "Ethylaluminum Dichloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.re044.pub2. ISBN 978-0471936237.
  3. Brendhaugen, Kristen; Haaland, Arne; Novak, David P.; Østvold, Terje; Bjørseth, Alf; Powell, D. L. (1974). "The Molecular Structure of Dimethylaluminium Chloride Dimer, [(CH3)2Al Cl]8, 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 structure of [(t Bu)2Al(μ-Cl)]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.
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