Carboxylates acid salts

A selection of important anionic surfactants is displayed in table C2.3.1. Carboxylic acid salts or tire soaps are tire best known anionic surfactants. These materials were originally derived from animal fats by saponification. The ionized carboxyl group provides tire anionic charge. Examples witlr hydrocarbon chains of fewer tlran ten carbon atoms are too soluble and tliose witlr chains longer tlran 20 carbon atoms are too insoluble to be useful in aqueous applications. They may be prepared witlr cations otlrer tlran sodium. 

II II, 1st 1920 152-194 Carboxylic Acids Salts and Derivatives. Formic acid, 8. Acetic acid, 96. 

A tertiary amine such as triethylamine is then added to the isocyanate-terminated prepolymer (containing carboxylic acid groups). The tertiary amine reacts with the pendant carboxylic acid groups, forming a carboxylic acid salt. The presence of this salt, together with adequate stirring, allows the dispersion of the prepolymer in water by the so-called melt dispersion process [57]. 

The two-component waterborne urethanes are similar in nature to the one-component waterborne urethanes. In fact, many one-component PUD s may benefit from the addition of a crosslinker. The two-component urethanes may have higher levels of carboxylic acid salt stabilizer built into the backbone than is actually needed to stabilize the urethane in water. As a result, if these two-component urethane dispersions were to be used as one-component adhesives by themselves (without crosslinker), they would show very poor moisture resistance. When these two-component urethane dispersions are used in conjunction with the crosslinkers listed in Fig. 8, the crosslinkers will react with the carboxylic pendant groups built into the urethane, as previously shown in the one-component waterborne urethane section. This accomplishes two tasks at the same time (1) when the crosslinker reacts with the carboxylic acid salt, it eliminates much of the hydrophilicity associated with urethane dispersion, and (2) it crosslinks the dispersion, which imparts solvent and moisture resistance to the urethane adhesive (see phase V in Fig. 5). As a result of crosslinking, the physical properties may be modified. For example, the results may be an increase in tensile properties and a decrease in elongation. Depending upon the level of crosslinking, the dispersion may lose the ability to be repositionable. (Many of the one-component PUD s may... 

Vinyl acetates are also fluormated by mixtures contammg both acyl hy-pofluorite and perfluoroalkyl hypofluorite, obtained from fluorinatton of the carboxylic acid salts [16 19] (equations 20 and 21)... 

Electrolysis of carboxylic acid salts m solution causes decaboxyladve coupling similar to Kolbe reaction. Thus, eleclrolysis of 3,3,3-trifluoro-2-trifluoromethyl-propanoic acid in die presence of some of its potassium salt gives the corresponding fluoroalkane in a satisfactory yield [7d] (equation 67). 

The carbanionic species thus formed is protonated to give the final product 3. The use of an alkoxide as base leads to formation of a carboxylic ester as rearrangement product use of a hydroxide will lead to formation of a carboxylic acid salt ... 

Saponification (Section 21.6) An old term for the base-induced hydrolysis of an ester to yield a carboxylic acid salt. 

An adhesive tape for photographic films can be made by using a coating containing a water- or alkali-soluble polymer and ether carboxylate [211]. A light-sensitive resin composition with ether carboxylic acid salt for flexographic plate material shows an improved flexibility and solvent resistance [212]. 

Unsymmetrical as well as symmetrical anhydrides are often prepared by the treatment of an acyl halide with a carboxylic acid salt. The compound C0CI2 has been used as a catalyst. If a metallic salt is used, Na , K , or Ag are the most common cations, but more often pyridine or another tertiary amine is added to the free acid and the salt thus formed is treated with the acyl halide. Mixed formic anhydrides are prepared from sodium formate and an aryl halide, by use of a solid-phase copolymer of pyridine-l-oxide. Symmetrical anhydrides can be prepared by reaction of the acyl halide with aqueous NaOH or NaHCOa under phase-transfer conditions, or with sodium bicarbonate with ultrasound. 

Anhydrides can be formed from certain carboxylic acid salts for example, by treatment of trimethylammonium carboxylates with phosgene ... 

The Conversion of Carboxylic Acid Salts to Ketones With Organometallic Compounds... 

Reaction between aryl halides and carboxylic acid salts... 

Acylation of carboxylic acid salts followed by cleavage... 

Alternatively, esterification of carboxylic acid can be carried out in aqueous media by reacting carboxylic acid salts with alkyl halides through nucleophilic substitutions (Eq. 9.10).20 The reaction rate of alkyl halides with alkali metal salts of carboxylic acids to give esters increases with the increasing concentration of catalyst, halide, and solvent polarity and is reduced by water. Various thymyl ethers and esters can be synthesized by the reactions of thymol with alkyl halides and acid chlorides, respectively, in aqueous medium under microwave irradiation (Eq. 9.11).21 Such an esterification reaction of poly(methacrylic acid) can be performed readily with alkyl halides using DBU in aqueous solutions, although the rate of the reaction decreases with increasing water content.22... 

Anionic Carboxylic acid salts Sulfuric acid ester salts Good detergency Good wetting agents Generally water-soluble Electrolyte-tolerant Electrolyte-sensitive... 

Various carboxylic acid salts have also been reported. Gallardo35 produced the maleate salt of neomycin which, it was claimed, improved the aqueous stability of the antibiotic. A practically tasteless compound, the citrate salt,has been described by Szyszka3 . Neomycin mandelate has been claimed to be particularly useful in the treatment of urogenital infections3 while the di-hydroxy-dinaphthylmethane-dicarboxylate4(3 and the pamoate salts43,67,68 have a low intestinal absorption and are thus effective treatments for intestinal infections. 

Not all neomycin salts, however, possess advantages such as a reduced toxicity. In fact, the orotic acid(1,2,3,6-tetrahydro-2,6-dioxo-4-pyrimidine carboxylic acid) salt was reported to have a greater toxicity than neomycin itself74f75. some uncertainty of this fact is apparent as other authors have reported the two compounds to be of a similar toxicity 6. The salt of neomycin with usnic acid(an antibacterial substance found in lichens) has been reported to have less antibacterial activity than the neomycin used in the preparation of the salt. 

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