Potassium aluminum isopropoxides

Abundant evidence has been gathered to show that pure alumina, prepared either from aluminum isopropoxide or aluminum nitrate and ammonia and calcined at 600-800°, has intrinsic acidic sites. Several physical methods have been used to study the acidity of alumina. Titration with butylamine (33), dioxane (34), and aqueous potassium hydroxide (35) as well as chemisorption of gaseous ammonia (35), trimethylamine (36), or pyridine (37) gave apparent acidity values which approximated those of silica-alumina. On the other hand, the indicator method for testing the acidity of solids as developed by Walling (3S) showed no indication of even weak acids (39, 40). 

The study of the product distribution from the isomerization of 3,3-dimethylbutene proved useful for evaluating the strength of the acid centers in aluminas (36). Pure alumina from aluminum isopropoxide which was calcined at 700° showed optimum activity. Heating at higher temperatures decreased the number of acid sites as well as their acid strength. Aluminas obtained from potassium or sodium aluminate contained alkali in amounts of 0.08 to 0.65%, depending on the way of precipitation and on the number of washings. 

Pure alumina catalyst prepared either by hydrolysis of aluminum isopropoxide or by precipitation of aluminum nitrate with ammonia, and calcined at 600-800°, contains intrinsic acidic and basic sites, which participate in the dehydration of alcohols. The acidic sites are not of equal strength and the relatively strong sites can be neutralized by incorporating as little as 0.1 % by weight of sodium or potassium ions or by passing ammonia or organic bases, such as pyridine or piperidine, over the alumina. 

Codeine sulfate trihydrate Ammonium hydroxide Aluminum isopropoxide Potassium sodium tartrate tetrahydrate Palladium on carbon... 

Ignition on contact with furfuryl alcohol powdered metals (e.g., magnesium iron) wood. Violent reaction with aluminum isopropoxide -f- heavy metal salts charcoal coal dimethylphenylphosphine hydrogen selenide lithium tetrahydroaluminate metals (e.g., potassium, sodium, lithium) metal oxides (e.g., cobalt oxide, iron oxide, lead oxide, lead hydroxide, manganese oxide, mercur oxide, nickel oxide) metal salts (e.g., calcium permanganate) methanol + phosphoric acid 4-methyl-2,4,6-triazatricyclo [5.2.2.0 ] undeca-8-ene-3,5-dione + potassium hydroxide a-phenylselenoketones phosphorus phosphorus (V) oxide tin(II) chloride unsaturated organic compounds. 

Oppenauer Aluminum r-butoxide. Aluminum isopropoxide. 1,4-Benzoquinone. Cyclohexanone. Potassium r-butoxide. 

Using aluminum isopropoxide as the reducing agent under thermodynamically controlled conditions (84.5 °C, 22 h), 2-(l-cyclohexenyl)butanone is converted to the more stable tram-2-(l-cyclohexenyl)cyclobutanol whereas the d.v-alcohol (80%) is obtained using the sterically more demanding boron reagent, potassium [hydrido-tris(l-methylpropyl)boranate]142. 

Fragmentation of an epoxy mesylate. The key step in a synthesis of the sesquiterpene lactone saussurea lactone (4) involved fragmentation of the epoxy mesylate (I), obtained from -santonin by several steps. When treated with aluminum isopropoxide in boiling toluene (N2, 72 hours), 1 is converted mainly into 3. The minor product (2) is the only product when the fragmentation is quenched after 12 hours. Other bases such as potassium r-butoxide, LDA, and... 

Reactions with Oxiranes, Oxetanes, and Aziridines. Lewis acids, lanthanide salts, and titanium tetraisopropoxide or aluminum isopropoxide catalyze the reactions of cyanotri-methylsilane with oxiranes, oxetanes, and aziridines, yielding ring-opened products. The nature of the products and the regio-selectivity of the reaction are primarily dependent on the nature of the Lewis acid, the substitution pattern in the substrate, and the reaction conditions. Monosubstituted oxiranes undergo regiospe-cific cleavage to form 3-(trimethylsiloxy)nitriles when refluxed with a slight excess of cyanotrimethylsilane in the presence of a catalytic amount of potassium cyanide-18-crown-6 complex (eqs 8-10). The addition of cyanide occurs exclusively at the least-substituted carbon. 

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