Carboxylate alkylation

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

Many Cu(I) compounds have polymeric structures with weak Cu—Cu bonds that are bridged by atoms or groups. These include Cu(I) carboxylates, alkyls and aryls, alkoxides and (CuXL) complexes (X = halide, L = ligand). In Cu(I) compounds Cu has a filled 3d shell, 3d , that does not participate in metal-metal bonding, so the extent of metal-metal bonding in these compounds is questionable. Calculations show that the metal-metal bonding is at best weak . These compounds arise from the same syntheses as would be used to prepare the monomer, and so they are not considered further here. 

Cobalt, Co3+ 6, octahedral O-Carboxylate, Alkyl group transfer in... 

A role for a collagenase, presumably fibroblast-type collagenase, in bone resorption has been indicated by studies employing the Searle A-carboxyl alkyl synthetic collagenase inhibitor CI-1 (compound (197) in Table 8.18) and its less potent stereoisomer CI-2 (compound (198) in Table 8.18) [207]. Cultured embryonic mouse calvaria treated with parathyroid hormone exhibit loss of calcium and show pronounced collagen resorption. CI-1 inhibited the collagen resorption in a dose-dependent manner at significantly lower concentrations than CI-2, but had only a small effect on calcium loss. This inhibitory effect was reversible and not due to inhibitor cytotoxicity. 

Especially for large-scale work, esters, may be more safely and efficiently prepared by reaction of carboxylate salts with alkyl halides or tosylates. Carboxylate anions are not very reactive nucleophiles so the best results are obtained in polar aprotic solvents54 or with crown ether catalysts.55 The reactivity for the salts is Na+ < K+ < Rb+ < Cs+. Cesium carboxylates are especially useful in polar aprotic solvents. The enhanced reactivity of the cesium salts is due both to high solubility and to the absence of ion pairing with the anion.56 Acetone has been found to be a good solvent for reaction of carboxylate anions with alkyl iodides.57 Cesium fluoride in DMF is another useful combination.58 Carboxylate alkylation procedures have been particularly advantageous for preparation of hindered esters that can be relatively difficult to prepare by the acid-catalyzed esterification method (Fischer esterification) which will be discussed in Section... 

Sections F and G of Scheme 3.2 give some specific examples of ester synthesis by the reaction of carboxylic acids with diazomethane and by carboxylate alkylation. 

Some of the amphipathic species that have been used in the investigation of reverse micelles are capable of dissociation under suitable conditions. Metal carboxylates, alkyl aryl sulfonates, sulfosuccinates, and alkyl ammonium salts are examples of compounds with a high degree of ionic character. Coulomb s law describes the force between two charges qK and q2 separated by a distance r in a medium of relative dielectric constant er... 

Keywords sodium carboxylate, halide, layered double hydroxide, carboxylate alkylation, microwave irradiation... 

The numerous substitution reactions lay in the background of the application of metal alkoxides in inorganic and metal-organic synthesis (preparation of halides, hydrides, sulfides, carboxylates, alkyl derivatives, certain classes of coordination compounds, etc.). One advantage of their application is the formation of only alcohols as by-products ... 

Scheme 20 Synthesis of heteroleptic tetramethylaluminate complexes via [carboxylate] [alkyl] exchange (top) or [alkyl] - [carboxylate] exchange (bottom, tetramethylaluminate route ) [147,148]...

Scheme 22 [Carboxylate]- -[alkyl] exchange a mechanistic scenario of the formation of differently alkylated lanthanide carboxylate complexes (except for Ij, and I2 all Ln complexes were completely characterized ArR = C6H2R 3-2,4,6 or C6H3R 2-2,6) [148]...

Te-alkyl arene- 7>-carboxylate alkyl aroyl tellurium... 

In 1962, Wieland and Vogeler [83] found the aminolysis of carboxylic alkyl ester in a melt with imidazole to be a good method for peptide bond construction. 

Surfactants used in the polymerization are water-soluble, halogenated surfactants. They are in particular fluorinated surfactant such as ammonium, substituted ammonium, quarternary ammonium, or alkali metal salts of perfluorinated or partially fluorinated alkyl carboxylates, monoalkyl phosphate esters, alkyl ether or polyether carboxylates, alkyl sulfonates, and alkyl sulfates. 

Polyoxyethylenated (POE) Fatty Alcohol Carboxylates (Alkyl Ether Carbox-ylates), R0(CH2CH20)xCH2C00M (x = 4, usually) Products of the reaction of the terminal OH group of an alcohol ethoxylate (AE) with sodium monochlor-oacetate. Less basic than soaps of comparable chain length, ascribed to the ether oxygen atom adjacent to the carboxylate group in the molecule. 

Both anionic and cationic type long-chain reagents are widely used in flotation as collectors. These include carboxylates, alkyl sulfonates, alkyl sulfates, alkyl amines and ehelating agents. Most minerals, except sulfides, require long-ehain eolleetors for their flotation. The behavior of long-chain collectors in solution is determined by the properties of the polar heads and hydrophobic tails and their resultant solvent power. 

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