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 Edit this at Wikidata
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
C8H20Al2Cl2
Molar mass 241.11 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 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
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).

Diethylaluminium chloride, abbreviated DEAC, is an organoaluminium compound. Although often 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]

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.[3][4] 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:[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

  1. ^ a b c d John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 4–40. ISBN 978-1138561632.
  2. ^ a b 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 [(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.

External links

Aluminium compounds
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