Aluminum oxyhalide

The reaction of aluminum halides with a variety of oxides at elevated temperatures yields the aluminum oxyhalides, AlOX (equation 34). These compounds are insoluble, moisture-sensitive compounds that have an interesting layered structure. The aluminum atoms have tetrahedral coordination by three oxygen atoms and one halide atom. The oxygen atoms of the tetrahedra are shared between three aluminum atoms, providing a puckered AlO layer. The halide atoms cap the tetrahedra, half of them above and half of them below the AlO layer in an alternating fashion. The hydrate of AlOCl is used as an antiperspirant. 

Just as in the isomerization of 124a, aluminum oxyhalides are effective in the isomerization of 123a (eq 15). 

Hypothesis A. Aluminum halide reacts with oxygen to yield aluminum oxyhalide and halogen. The latter reacts with the alkanes to form alkyl halides and hydrogen halide. 

Ziegler-Natta Catalysts (Heterogeneous). These systems consist of a combination of a transition metal compound from groups IV to VIII and an organometallic compound of a group I—III metal.23 The transition metal compound is called the catalyst and the organometallic compound the cocatalyst. Typically the catalyst is a halide or oxyhalide of titanium, chromium, vanadium, zirconium, or molybdenum. The cocatalyst is often an alkyl, aryl, or halide of aluminum, lithium, zinc, tin, cadmium, magnesium, or beryllium.24 One of the most important catalyst systems is the titanium trihalides or tetra-halides combined with a trialkylaluminum compound. 

Most commonly, the catalyst component consists of halides or oxyhalides of titanium, vanadium, chromium, molybdenum, or zirconium, and the cocatalyst component often consists of an alkyl, aryl, or hydride of metals such as aluminum, lithium, zinc, tin, cadmium, beryllium, and magnesium. The catalyst systems may be heterogeneous (some titanium-based systems) or soluble (most vanadium-containing species). Perhaps the best known systems are those derived from TiCl4 or TiCls and an aluminum trialkyl. 

US EPA Method 326.0 allows the combination of suppressed conductivity detection and postcolumn derivatization for UV absorbance detection, as schematically depicted in Figure 8.45. A volume of sample (225 pL) is introduced into an ion chromatography system. After separation and eluent suppression, standard anions and oxyhalide ions are measured using conductivity detection. The suppressed effluent from the conductivity detector is then combined with an acidic solution of potassium iodide (0.26 mol/L) containing a catalytic amoimt of ammonium molybdate tetrahydrate (43 pmol/L). The mixture is heated in the knitted reaction coil to 80 °C to facilitate complete reaction. The formed triiodide is measured by its UV absorption at 352 nm. Because KI is photosensitive, the KI/Mo PCR solution develops a light yellow color with time, even when stored under helium. Therefore, the PCR reservoir has to be protected from light by covering it with aluminum foil and should be pressimzed with helium. Under... 

One of the ways to dispose of chemicals that are reactive with water is hydrolysis, that is, the reaction with water under controlled conditions. Inorganic chemicals that can be treated by hydrolysis include metals that react with water metal carbides, hydrides, amides, alkoxides, and halides and nonmetal oxyhalides and sulfides. An example of a waste chemical treated by hydrolysis is the reaction with water of sodium aluminum hydride (used as a reducing agent in organic chemical reactions) ... 

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