Aluminum complexes carboxylates

Aluminum salts of carboxylic acids, aluminum carboxylates, may occur as aluminum tricarboxylates (normal aluminum carboxylates), Al(OOCR)2 monohydroxy (monobasic) aluminum dicarboxylates, (RCOO)2Al(OH) and dihydroxy (dibasic) aluminum monocarboxylates, RCOOAl(OH)2. Aluminum carboxylates are used in three general areas textiles, gelling, and pharmaceuticals. Derivatives of low molecular weight carboxyUc acids have been mainly associated with textile appHcations those of fatty carboxyUc acids are associated with gelling salts and more complex carboxylates find appHcations in pharmaceuticals. 

Aluminum Salts of More Complex Carboxylic Acids... 

A very extensive investigation of the reaction of pyridine and lithium aluminum hydride has been made by Lansbury and Peterson.60-82 These authors found that an aged solution of LAH in pyridine possessed unusual and selective reductive properties. Ketones and aldehydes were reduced while carboxylic acids were not, and diaryl ketones were reduced more readily than dialkyl ketones. These distinctive properties were found to result from a dihydropyridine-aluminum complex formed by the reaction of LAH and pyridine. 

Existence of carboxylate-Al(ni)-OH dimers has been inferred from a large number of very careful potentiometric studies of aluminum complexation by organic acids (e g., oxalic acid—Sjoberg and Ohman 1985 lactic acid—Marklund and Ohman 1990 phthalic acid— Hedlund et al. 1987a carbonic acid—Hedlund et al. 1987b). None of these postulated dimeric structures have been yet confirmed by X-ray structural study of... 

In addition, as mentioned above, the polymer-supported complexes possess the bidentate carboxylate group, and the metal-oxygen bonds in these complexes are rich in covalency. For Ziegler-Natta catalysts, one of the requirements for the formation of the active center is the alkylation of the metal ions by exchange between the alkyl group in alkyl aluminum and carboxylate. The covalency of the metal-oxygen bond in the support complex makes this exchange reaction easier. 

Dihydro-5-oxo-1-(4-sulfophenyl)-4-((4-sulfophenyl) azo)-1 H-pyrazole-3-carboxylic acid aluminum complex. See Pigment yellow 100... 

Synonyms Aluminum indigo carmine Certolake tartrazine Certolake tartrazol yellow Cl 19140 1 Cl 19140 aluminum lake Cl pigment yellow 100 4,5-Dihydro-5-oxo-1-(4-sulfophenyl)-4-((4-sulfophenyl) azo)-1 H-pyrazole-3-carboxylic acid aluminum complex FD C Yellow No. 5 aluminum lake Food yellow 4 aluminum lake Yellow lake T Empirical C16H9AIN4O9... 

High aluminum concentrations in carboxylic acid/silicate dissolution experiments have been interpreted in terms of formation of organic anion-aluminum complexes (Surdam et al. 1984 Surdam and MacGowan 1987 ... 

Because hydride ion is a base as well as a nucleophile, the actual nucleophilic acyl substitution step takes place on the carboxylate ion rather than on the free carboxylic acid and gives a high-energy dianion intermediate. In this intermediate, the two oxygens are undoubtedly complexed to a Lewis acidic aluminum species. Thus, the reaction is relatively difficult, and acid reductions require higher temperatures and extended reaction times. 

Good non-colored negative charging CCAs have been obtained by making non-colored analogues of the 2 1 chromium complex azo dyes. This is achieved by making the metal complex of an aromatic ortho-hydroxy carboxylic acid. Typical examples are the chromium, aluminum, and zinc complexes of di-tert-butyl salicylic acid, e.g., BONTRON E-8136 41 (53) and BON-acid36,41,42 e.g., BONTRON E-82 (54). 

The reduction of free acids to alcohols became practical only after the advent of complex hydrides. Lithium aluminum hydride reduces carboxylic acids to alcohols in ether solution very rapidly in an exothermic reaction. Because of the presence of acidic hydrogen in the carboxylic acid an additional equivalent of lithium aluminum hydride is needed beyond the amount required for the reduction. The stoichiometric ratio is 4 mol of the acid to 3 mol of lithium aluminum hydride (Equation 12, p. 18). Trimethylacetic add was reduced to neopentyl alcohol in 92% yield, and stearic acid to 1-octadecanol in 91% yield. Dicarboxylic sebacic acid was reduced to 1,10-decanedioI even if less than the needed amount of lithiiun aluminum hydride was used [968]. 

Reduction of aromatic carboxylic acids to alcohols can be achieved by hydrides and complex hydrides, e.g. lithium aluminum hydride 968], sodium aluminum hydride [55] and sodium bis 2-methoxyethoxy)aluminum hydride [544, 969, 970], and with borane (diborane) [976] prepared from sodium borohydride and boron trifluoride etherate [971, 977] or aluminum chloride [755, 975] in diglyme. Sodium borohydride alone does not reduce free carboxylic acids. Anthranilic acid was reduced to the corresponding alcohol by electroreduction in sulfuric acid at 20-30° in 69-78% yield [979],... 

Cationic polymerization of alkylene oxides generally produces low molecular weight polymers, although some work [26] seems to indicate that this difficulty can be overcome by the presence of an alcohol (Fig. 1.3). Higher molecular weight polyethylene oxides can be prepared by a coordinated nucleophilic mechanism that employs such catalysts as alkoxides, oxides, carbonates, and carboxylates, or chelates of alkaline earth metals (Fig. 1.4). An aluminum-porphyrin complex is claimed to generate immortal polymers from alkylene oxides that are totally free from termination reaction [27]. 

While high polymers of /3-lactones can also be formed by cationic polymerization, most of the commercial production seems to be by the anionic route. Carboxylate salts such as sodium acetate or benzoate are commonly the initiators, but other nucleophiles, such as triethylamine, betaine, potassium f-butoxide, aluminum and zinc alkoxides, various metal oxides and tris(dimethylamino)benzylphosphonium chloride (the anion of which is the initiator), are of value. Addition of crown ethers to complex the counter cation increases the rate of reaction. When the reaction is carried out in inert but somewhat polar organic solvents, such as THF or ethyk acetate, or without solvent, chain propagation is very fast and proceeds without transfer reactions. 

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