Aluminum dichloride

Trimethyl aluminum and propylene oxide form a mixture of 2-methyl-1-propanol and 2-butanol (105). Triethyl aluminum yields products of 2-methyl-1-butanol and 2-pentanol (106). The ratio of products is determined by the ratio of reactants. Hydrolysis of the products of methyl aluminum dichloride and propylene oxide results ia 2-methylpropeae and 2-butene, with elimination of methane (105). Numerous other nucleophilic (107) and electrophilic (108) reactions of propylene oxide have been described ia the Hterature. 

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]. 

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 ... 

Controlled alkylation of phosphorus oxychloride may also be accomplished using a modification of this approach. Reaction of alkyl-aluminum dichloride with phosphorus oxychloride generates the aluminum chloride complex of the alkylphosphonodichlori-date,54 which may be isolated as the simple compound or directly used in reaction to generate other derivatives of the alkylphospho-nic acid. 

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. 

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.

GL-Trimethylsilyl-oi, -enones.ls These useful Michael acceptors (2) can be prepared by rearrangement of l-(trimethylsilyl)-2-propynyl trimethylsilyl ethers (1) with methyl-aluminum dichloride. 

Fig. 14. Molecular structure of dimeric vinylsilyloxy-aluminum dichloride [(CH2=CHSiH2)OAlCl2]2 [34]...

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 alkyrlaluminums were obtained from Texas Alkyls Inc. and purified by vacuum distillation in nitrogen atmosphere. B.P. °C/mm Hg MCaAl 60768.5 EtjAl 977100 Et AlCl 125-126750mm MejAlCl 847200. Prior to distillation the dialkylaluminum chlorides were stirred over dry sodium chloride at 80° C for 2 hrs. to remove alkyl-aluminum dichlorides. The distilled dialkylaluminum chlorides were stored over sodium chloride to prevent the accumulation of the dihalide. 

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. 

A Lewis acid prepared from (-)-menthol and ethyl aluminum dichloride has also been examined as a catalyst for the ene reaction [62], As would be expected, this catalyst is apparently faster than the dialkoxy methyl aluminum catalyst 98 and results in 75 % yield of the homoallylic alcohol 305 with 10 mol % catalyst at -78 °C. It is sur-... 

Dioctylamine 1120-48-5 Ethyl Aluminum Dichloride 563-43-9 Ferric Nitrate 10421-48-4... 

Lactic Acid 5394-83-2 Camphoric Acid 563-43-9 Ethyl Aluminum Dichloride... 

Figure 3 Simplified flow chart for the conventional aluminum dichloride process using DCE (1,2 dichloroethane) as solvent...

Potential Lewis acidic species for this transformation are aluminum(III) chloride, ethyl-aluminum dichloride or methylaluminum sesquichloride. Reaction with this last reagent is found to occur less rapidly although the resulting yields of product are maximized. A number of common Lewis acids are unsuitable for this transformation, e.g., boron trifluoride diethyl ether complex, zinc chloride, and this may be attributed to preferential interaction of the Lewis acid with the allylstannane component. 

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