Alkylaluminum halide

So far it has not been possible to determine the distribution of the third monomer units in molecular chains. Yet it is possible to follow the rate of third monomer incorporation in polymerization so as to estimate the heterogeneity of its distribution in the whole polymer. We have previously reported the marked difference in incorporation of DCFD in polymerization with V(acac)3 Et2AlCl and Vc q-Et3Al2Cl -ETGA (3). Figure 8 shows that V. in combination with various alkylaluminum halides and VOCL -Et.Al.Cl are not noticeably different in influencing the incor-pola. uluu of DCED during EEDM polymerization. Thus, difference in... 

Aluminum(III) complexes are amongst the most common Lewis acids. In particular, aluminum halide species (e.g., A1C13, AlBr3) are commercially available and are widely used for various reactions. Other types of Lewis acid such as aluminum alkoxides, alkylaluminum halides, and trialkylaluminum species are also used for many kinds of Lewis-acid-mediated reactions. 

AICI3 is a moisture-sensitive and strong Lewis acid. It is a first choice for Friedel-Crafts-type reactions, which provide numerous important transformations in laboratory and industry. It can also be applied to the transformation of alkenes to ketones via alkylaluminum halides.303 Hydrozirconation of an olefin and subsequent transmetalation from zirconium to aluminum gives the corresponding alkylaluminum dichloride, and the subsequent acetylation by acetyl chloride affords the corresponding ketone in high yield (Scheme 66). 

B,) Treatment of an organo- or a hydrido-nickel(II) compound with a Lewis acid. Organometallic compounds, such as alkylaluminum halides, which have Lewis acid properties, can also be used. 

Dialkylaluminum halides, alkylaluminum dihalides, and alkylaluminum sesquihalides will be referred to henceforth as alkylaluminum halides. ... 

Not only phosphines or phosphites but also phosphoric acid trisdialkyl-amides (40), sulfoxides (41), etc. have been used as electron donors in the preparation of the catalyst. In addition, the catalytic activity of tetra-methylcyclobutadienenickel dichloride and alkylaluminum halides has been studied in detail (42, 43). 

The primary (7, 47) and most commonly used organonickel compounds have been the dimeric 7r-allyl- (or substituted Tr-allyl-) nickel halides (1) (Scheme 1) or their monophosphine adducts (2) in the presence of Lewis acids such as aluminum halides or alkylaluminum halides (4, 48-53). The... 

There can be little doubt that the active species involved in most or even all of the various combinations described in Section II is HNi(L)Y (see below), because the different catalysts prepared by activating the nickel with Lewis acids have been shown to produce, under comparable conditions, dimers and codimers which have not only identical structures but identical compositions. On modification of these catalysts by phosphines, the composition of dimers and codimers changes in a characteristic manner independent of both the method of preparation and the nickel compound (2, 4, 7, 16, 17, 26, 29, 42, 47, 76). Similar catalysts are formed when organometallic or zero-valent nickel complexes are activated with strong Lewis acids other than aluminum halides or alkylaluminum halides, e.g., BFS. 

Less clear is the sequence which leads to the formation of the active species in the case of catalysts prepared from zero-valent nickel complexes and aluminum halides or alkylaluminum halides (method C2). The catalytic properties of these systems, however—in particular, the influence of phosphines (76)—leaves no doubt that the active species is also of the HNiY type discussed above. In this connection, a recent electron spin resonance report that nickel(I) species are formed in the reaction of COD2Ni with AlBr3 (83 ), and the disproportionation of Ni(I) to Ni(II) and Ni(0) in the presence of Lewis acids (69) should be mentioned. 

Ene catalyst.1 FeCl3 is superior to ZnBr2 or alkylaluminum halides as a catalyst for ene cyclization of the chiral 1,7-diene 1, the Knoevenagel adduct from citronellal and dimethyl malonate. Thermal cyclization provides the 1,2-trans-substituted... 

VDC polymer degradation and, 25 717 2-Alkyl-alcohols. See Guerbet alcohols Alkylalkanolamines, 2 140 Alkylaluminum compounds, 2 285 Alkylaluminum halides, 2 358 Alkylaluminum reagents, in triorganotin preparation, 24 815-816 Alkyl amino acids, protonated, 17 780 Alkylaminomethanols, 12 112 AT-Alkyl amino propionates, 24 148... 

The low-pressure polymerization of olefins using Ziegler-Natta catalysts, i.e., mixtures of compounds of transition groups IV to VI of the periodic table of the elements together with organometallic compounds of groups I to III is widely applied. Such catalysts, consist of titanium alkyl compounds and aluminum alkyl compounds or alkylaluminum halides. 

Hie study of effects of the catalyst components also help clarify the ionic factors in the steric control of isotactic polyvinylethers. Dall Asta and Bassi (15) studied the polymerization of butylvinylether with various alkylaluminum halides. They found that diethylaluminum chloride and ethylaluminum dichloride were the most effective catalysts for the production of isotactic polymer. Ethylaluminum dibromide and ethoxyaluminum dichloride were of questionable effectiveness, while diethylaluminum fluoride was completely ineffective. 

Fig. 3 shows the catalysts in relative qualitative position in the chart of ionicities. The alkylaluminum halides and titanium halides are placed according to their electrophilic or cationic polymerization strength. The exact quantitative positions relative to Bawn s and Ledwith s representation of ionic freedom have not been established. 

Lithium diallylcuprate, 11 Lithium dibutylcuprate, 61 Lithium dimethylcuprate, 63, 258 Sakurai reaction Alkylaluminum halides, 5 Allyltrimethylsilane, 11, 305 Titanium(IV) chloride, 304 with other organometallic agents (IS, 2S) -2-Amino-3-methoxy-1 -pheny 1-1-propanol, 17... 

Lithium butyldimethylzincate, 221 Lithium sec-butyldimethylzincate, 221 Organolithium reagents, 94 Organotitanium reagents, 213 Palladium(II) chloride, 234 Titanium(III) chloride-Diisobutylalu-minum hydride, 303 Tributyltin chloride, 315 Tributyl(trimethylsilyl)tin, 212 3-Trimethylsilyl-l, 2-butadiene, 305 Zinc-copper couple, 348 Intramolecular conjugate additions Alkylaluminum halides, 5 Potassium t-butoxide, 252 Tetrabutylammonium fluoride, 11 Titanium(IV) chloride, 304 Zirconium(IV) propoxide, 352 Miscellaneous reactions 2-(Phenylseleno)acrylonitrile, 244 9-(Phenylseleno)-9-borabicyclo[3.3.1]-nonane, 245 Quina alkaloids, 264 Tributyltin hydride, 316 Conjugate reduction (see Reduction reactions)... 

General considerations, 281 Intramolecular Alkylaluminum halides, 5 Dicarbonylcyclopentadienylcobalt, 96 Meldrum s acid, 172 Specific reactions 2-Acetoxy-l, 3-butadiene, 71... 

Grignard reagents, 138 Methyl acrylate, 183 Cyclohexanols by other routes Alkylaluminum halides, 5 Tin(II) trifluoromethanesulfonate, 301... 

Seven-membered rings Iodine-Mercury(II) oxide, 149 Potassium /-butoxide, 252 Eight-membered rings Alkylaluminum halides, 5 Medium to large rings Tributyltin hydride, 316 Bicyclic [6,6] ring systems... 

Alkylaluminum halides, 5 Palladium catalysts, 230 2,4,4,6-Tetrabromo-2,5-cyclohexadi-enone,285... 

Diels-Alder catalysts Alkylaluminum halides, 5, 173 Boron trifluoride etherate, 43 Diethylaluminum chloride, 173 Dimethylaluminum chloride, 5 Sodium dodecyl sulfate, 281 Titanium(IV) chloride-Diethylaluminum chloride, 309... 

Tricarbonyl(naphthalene)chromium, 19 Tungsten carbonyl, 49 Metal-containing compounds Aluminum Compounds Alkylaluminum halides, 5, 25, 44, 173, 306... 

Alkylaluminum halides have been investigated as catalysts in the benzalaniline-diazomethane addition.342 Reaction occurs at — 78°C in the presence of diethylaluminum chloride to yield the triazoline adduct diethyl-aluminum iodide, however, leads only to an aziridine. 

Upon completion of the reaction the reaction mixture was treated with a diluent which is a nonsolvent for PVC. Suitable diluents included aliphatic or aromatic hydrocarbons such as hexane, heptane, or benzene or compounds containing an active hydrogen atom such as acetic acid or a lower alkanol such as methanol or ethanol. Methanol was the preferred diluent by virtue of its miscibility with the preferred reaction medium (chlorobenzene), its ability to react readily with and deactivate an aluminum alkyl or alkylaluminum halide, and its low boiling point and water solubility. 

---