Ethyl aluminum dichloride

Chemical Designations - Synonyms Aluminum ethyl dichloride EADC Chemical Formula CjHjAICIj. 

ETHYLAMINUM DICHLORIDE EADC, Aluminum Ethyl Dichloride Flammable Liquid 3 3 3 W... 

Group I-III metal aUcyl components are essential to the formation of active centers [239, 240]. Blue complexes of di cyclopentadienyl titanium dichloride with aluminum diethyl chloride or with aluminum ethyl dichloride were some of the early known soluble catalysts [257, 258] ... 

Ethylaluminum Dichloride — (i) Chemical Designations — Anonyms Aluminum ethyl dichloride EADC Chenucal Formula CjHjAICIj (ii) Observable Characteristics — Physical State (as normally shipped) Liquid Color Colorless to light amber yellow Odor Not pertinent (iii) Physical and Chemical Properties — Physical State at 15 X and 1 atm. Solid Molecular... 

Using a solution process, the choice of catalyst system is determined, among other things, by the nature of the third monomer and factors such as the width of the mol wt distribution to be realised in the product. A number of articles review the induence of catalyst systems on the stmctural features of the products obtained (3,5—7). The catalyst comprises two main components first, a transition-metal haHde, such as TiCl, VCl, VOCl, etc, of which VOCl is the most widely used second, a metal alkyl component such as (C2H )2A1C1 diethylalurninum chloride, or monoethyl aluminum dichloride, (C2H )AlCl2, or most commonly a mixture of the two, ie, ethyl aluminum sesquichloride, [(C2H )2Al2Cl2]. 

Addition. Addition reactions of ethylene have considerable importance and lead to the production of ethylene dichloride, ethylene dibromide, and ethyl chloride by halogenation—hydrohalogenation ethylbenzene, ethyltoluene, and aluminum alkyls by alkylation a-olefms by oligomerization ethanol by hydration and propionaldehyde by hydroformylation. 

Ethyl aluminum dichloride (EADC) is used in the rnanufacmre of certain catalysts for making LDPE. Occasionally, the batch operation involving the catalyst production results in an off-spec lot. This off-spec lot is washed from the reactor (impregantor) with water and hexane, and must be sent to a waste disposal facility. The facility treats this waste in a hydrolysis reaction (i.e., with water and mild agitation). If the reaction is exothermic, what are the potential air pollution and fire problems associated with the waste treatment ... 

Ethyl aluminum dichloride can catalyze the intramolecular cycloaddition of dienones 1 giving polycyclic cyclobutanes 2 in good yields.21 The effect of temperature and catalyst is important in determining the extent of [2 + 2] cycloadducts and ene-type products formed. 

Long (81) showed that the complex from biscyclopentadienyltitanium dichloride and methylaluminum chloride or a simply derived product from it, was an active ethylene polymerization catalyst. There have been a number of attempts to determine the exact nature of initiation in polyethylene. However, by any techniques available until now, it has not been possible to determine the actual ionic nature of the active catalyst which polymerizes ethylene. Karapinka and Carrick (82) studied the polymerization of ethylene with biscyclopentadienyltitanium dichloride and various alkylaluminum compounds. They found that the alkyl group exchanged so readily between the aluminum and titanium, that the location of the initiating site could not be determined. All that could be concluded was that an ethyl group initiated the polymerization more easily than the phenyl. 

Breslow and Newburg (125) studied the reaction of biscyclopenta-dienyltitanium dichloride and alkyl aluminums. They postulated that the reduction of the metal occured through an intermediate dialkylation which rapidly eliminated olefin and alkane. Bawn (126) has found that the reaction of cobalt acetylaeetonate and triethylaluminum gives disproportionation to ethane and ethylene at the beginning and dimerization of the ethyl group to butane at the end. 

Soluble catalysts, such as diethyl aluminum chloride and ethyl aluminum dichloride, also affect the stereoregularity of the polymer chains. The tendency for the formation of stereoregular polymers is decreased as the size of the alkyl group is increased. Typical structures of these polymers are shown below ... 

An alternate route to formation of alkyl monolayers is via Lewis acid catalyzed reactions of alkenes with the hydrogen terminated surface. In this approach, a catalyst such as ethyl aluminum dichloride is used to mediate the hydrosilylation reaction of an alkene (or alkyne), resulting in the same type of product as in the case of the photochemical or thermal reactions. This type of reaction is well known based on molecular organosilane chemistry and has also been used successfully to alkylate porous silicon [31]. Although this route has been shown to work on H/Si(lll), the resulting monolayers are found to have lower coverages than those achieved using the photochemical or thermal approach [29], Another concern with this approach is the possibility of trace metal residues from the catalyst that could adversely affect the electronic properties of these surfaces (even when present at levels below the detection limit of most common surface analysis techniques). 

The ethyl aluminum dichloride-catalyzed synthesis of (7 )-(+)-cyclohex-3-enecarboxylic acid, using galvinoxyl to inhibit polymerization, has been successfully scaled up to the kilogram level.106 An improved synthesis of the chiral auxiliary, /V-acryloylbornane-10,2-sultam, was also described together with a recycle protocol. 

The ethyl aluminum dichloride-catalyzed Michael alkylations of some indoles with N-(diphcnylmethylcnc)-a,()-didehydroamino acid esters allowed successful short synthesis of the tryptophan derivative and the 1,1-diphenyl-p-carboline derivatives, as well as compounds 253 and 252 (Scheme 55) [ 178]. 

Figure 1. Dependence of complex stability (i.e., polymer yield) on reaction temperature Propylene, 50 grams acrylonitrile, 2 grams ethyl-aluminum dichloride, 50 mmoles toluene, 30 ml. reaction time, 30 min.

Ethyl aluminum dichloride mediates a formal [5 + 2] cycloaddition of complex (164) and (166) with enol silyl ethers to produce the highly strained seven-membered rings (165) and (167) respectively (Schemes 239 -240). Excellent stereoselectivity is observed in both cases. A related double alkylation affords complexed seven-membered rings via a formal [4 - - 3] cycloaddition. Incorporation of fluorine is observed using boron trifluoride etherate (Scheme 241). 

Alkyl halides are widely used as cocatalysts in combination with aluminum alkyl halides or aluminum halide Lewis acids. Tlie reaction scheme in Fig. 9-2 illustrates the complicated equilibria which may affect the initiation process. Each carbenium ion can initiate polymerization or remove an ethyl group from the counterion to produce a saturated hydrocarbon, REt, and a new more acidic Lewis acid. The propagating macrocarbenium ions can also terminate by the same process to produce ethyl-capped polymers and new Lewis acids. Thus, even though the initiator is ostensibly dielhylaluminum chloride there may be major contributions to the polymerization from ethyl aluminum dichloride or aluminum chloride. 

The optimum catalyst for the reaction of 175 and cyclopentadiene was generated in-situ from one equivalent of the diol and two equivalents of ethyl aluminum dichloride. Presumably this generates a Lewis acid with two dichloroalkoxy aluminum groups per molecule of catalyst. The catalyst generated from diol 181 and one equivalent of diethylaluminum chloride is not very active, possibly because here the catalyst is a di-alkoxy aluminum chloride. The highest induction was observed for a catalyst generated from the diamino substituted diol 187, which was prepared from tartaric acid. 

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