Sodium carboxylate-carboxylic acid system

The Sodium Carboxylate/Carboxylic Acid System. This system has been investigated using IR and showing the extremely... 

One feature of this oxidation system is that it can selectively oxidize primary alcohols in preference to secondary alcohols, as illustrated by Entry 2 in Scheme 12.5. The reagent can also be used to oxidize primary alcohols to carboxylic acids by a subsequent oxidation with sodium chlorite.34 Entry 3 shows the selective oxidation of a primary alcohol in a carbohydrate to a carboxylic acid without affecting the secondary alcohol group. Entry 5 is a large-scale preparation that uses NaC102 in conjunction with bleach as the stoichiometric oxidant. 

Available information on DEHPA indicates an effect of salt concentration similar to that shown for the carboxylic acids [17]. Figure 7.11 indicates a significant difference between sodium and ammonium salts and solutions containing sodium and ammonium hydroxides. Moreover, below about 5 wt% salt concentration, the solubility becomes uneconomic. However, all the data given in Fig. 7.11 are for alkaline systems. For acid systems... 

An enolate anion generated from a carboxylic acid derivative may be used in the same sorts of nucleophilic reactions that we have seen with aldehyde and ketone systems. It should be noted, however, that the base used to generate the enolate anion must be chosen carefully. If sodium hydroxide were used, then hydrolysis of the carboxylic derivative to the acid (see Section 7.9.2) would compete with enolate anion formation. However, the problem is avoided by using the same base, e.g. ethoxide, as is present in the ester... 

Taylor and Flood could show that polystyrene-bound phenylselenic acid in the presence of TBHP can catalyze the oxidation of benzylic alcohols to ketones or aldehydes in a biphasic system (polymer-TBHP/alcohol in CCI4) in good yields (69-100%) (Scheme 117) °. No overoxidation of aldehydes to carboxylic acids was observed and unactivated allylic alcohols or aliphatic alcohols were unreactive under these conditions. In 1999, Berkessel and Sklorz presented a manganese-catalyzed method for the oxidation of primary and secondary alcohols to the corresponding carboxylic acids and ketones (Scheme 118). The authors employed the Mn-tmtacn complex (Mn/168a) in the presence of sodium ascorbate as very efficient cocatalyst and 30% H2O2 as oxidant to oxidize 1-butanol to butyric acid and 2-pentanol to 2-pentanone in yields of 90% and 97%, respectively. This catalytic system shows very good catalytic activity, as can be seen from the fact that for the oxidation of 2-pentanol as little as 0.03% of the catalyst is necessary to obtain the ketone in excellent yield. 

The dibenzopyranone ring system may be viewed as a chromone with an additional fused benzene ring and thus generally related to the antiasthmatic mediator release inhibitor cromolyn (see Chapter 11). Two dibenzopyranones have in fact been investigated for this indication in the clinic. Friedel-Crafts cyclization of the substituted cresyloxybenzoic acid (2-1) in sulfuric acid leads to the dibenzopyranone (2-2). The methyl group is then oxidized to a carboxylic acid by means of chromic acid. The acid is then converted to its sodium salt, xanoxate sodium (2-3) [2]. 

Hand in hand with this research on finding a suitable carboxylic acid chemical for cross-linker has been the search for an economical catalyst system. The catalyst found to be most effective for the esterification reaction was sodium hypophosphite (NaH PO. This material was also costly and out of range for the textile industry. Because weak bases function as catalyst, a range of bases has been explored, including the sodium salts of acids such as malic acid. 

Walther et al. improved the Na0Ph/C02 system by tuning the role of the solvent, such that the carboxylation of acetone was carried out selectively by sodium phenoxide with N-methyl-caprolactam under 0.1 MPa C02 to afford 3-ketoglutaric acid in 65% yield [34]. The same authors reported the conversion of acetyl-naphthalene (acetonaphthone) to acetyl-naphthalene carboxylic acid with 84% yield, and of cyclohexanone to cyclohexane-2,6-dicarboxylic acid in 56% yield. 

The head groups of these surfactant molecules are negatively charged. The most widely used anionic surfactants are those containing carboxylate groups, such as soaps, sulfonate, and sulfate ions Soaps, which are salts of weak carboxylic acids, are formed by the hydrolysis of fats (triglycerides) by sodium hydroxide. Sulfonates, such as sodium docusate and decane sulfonate, have been widel used in pharmaceutical systems. The most popular alkyl sulfate is sodium lauryl sulfate, which is... 

G. W. Gribble, Sodium Borohydride in Carboxylic Acid Media A Phenomenal Reduction System, Chem. Soc. Rev. 1998, 27, 395-404. 

A reversed-phase HPLC post-column ion-pair extraction system was developed by Kim and Stewart [71, 72] for the analysis of carboxylic acid drugs and their salts (sodium formate, sodium acetate, 3-bromopropionic acid, 6-aminocaproic acid, 11-bromoundecanoic acid, 1-heptanesulfonic acid, / -n i t rophcny 1 acetic acid, sodium benzoate, sodium salicylate, valproic acid, probenecid, naproxen, ketoprofen, ibuprofen, mefenamic acid, flufenamic acid, and cefuroxime sodium) using a-(3,4-dimethoxy-phenyl)-4,-trimethylammoniummethylcinnamonitrile methosulfate... 

---