Sodium carboxylic acids

ZINC BROMIDE (7699-45-8) BrjZn Noncombustible solid. An acidic material. Violent reaction with alkali metals, including metallic sodium, carboxylic acid inorganic oxoacids potassium. Incompatible with bases, amines, amides, inorganic hydroxides. Store above 32°F/0°C. 

Carboxylates s. Copper carboxylates, Sodium -Carboxylic acid amid... s. a. Amid... 

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. 

Conversion of a sodium salt of a carboxylic acid into the free acid e.g., if R-SO H represents the cation exchange resin ... 

When the phenol contains a carboxylic acid group, e.g., m- or p-hydroxy-benzoic acid, the acetylated derivative will of course remain in solution as the sodium salt, but is precipitated when the solution is subsequently acidified. Salicylic acid, however, cannot be acetylated under these conditions. 

Sodium benzoate,—Burns with great difficulty, and after prolonged heating leaves a white infusible residue of NajCOj. Scrape this residue into a test-tube, and test for carbonate in the usual way. Typical of alkali salts of carboxylic acids. 

Solubility in sodium carbonate solution. See Section 5 (p. 330), and also Test 2 for carboxylic acids (p. 347). 

Since the silver salts of the carboxylic acids are usually soluble in dilute nitric acid, they must be prepared by treating an aqueous solution of a neutral salt of the acid (and not the free acid itself) with silver nitrate solution. It is not practicable to attempt to neutralise the acid with sodium or potassium hydroxide solution, because the least excess of alkali would subsequently cause the white silver salt to be contaminated with brown silver oxide. The general method used therefore to obtain a neutral solution j to dissolve the acid in a small excess of ammonia solution, and then to boil the solution until all free... 

The molecular weight of many carboxylic acids which arc freely soluble in cold water (i.e., chiefly the aliphatic acids) can readily be obtained by titrating a known weight of the acids in aqueous solution with standard sodium or potassium hydroxide solution, using phenolphthalein as an indicator. To avoid the use of unduly large quantities of the acid, it is advisable to use Mj2 caustic alkali solution, and in order to obtain a sharp end>point, this alkali solution... 

Nitroethane may be similarly obtained from sodium a chloropropionate. This is a general reaction for a chloro carboxylic acids, but in practice only monochloroacetic acid and a chloropropionic acid are readily available. 

Phenylglycine-o-carboxylic acid. In a 750 ml. round-bottomed flask, fitted with a reflux condenser, place 14 g. of anthranilic acid (Section IV,170), 10 g. of chloroacetic acid, 20 g. of anhydrous sodium carbonate and 200 ml. of water. Reflux the mixture for. 3 hours, then pour into a beaker, cool, render shghtly acid with concentrated hy dro-chloric acid, and allow to stand overnight. Filter off the crude acid and wash it with water. Recrystalhse from hot water with the aid of a little decolourising carbon, and dry the acid at 100°. The yield of phenyl-glycine-o-carboxyhc acid, m.p. 208°, is 12 g. 

Dilute sodium hydroxide solution. Carboxylic acids (RCOOH), sulphonic acids (RSO3H), phenols (ArOH), thiophenols (ArSH), mer-captans (RSH), imides (RCONHCOR), aryl sulphonamides (AxSOjNHj), arylsulphonyl derivatives of primary amines (AxSOjNHR), oximes (RCH=NOH), primary and secondary nitro compounds (RCH=NOOH and RjC=NOOH-oci forms), and some enols (e.g., of 1 3-diketones... 

The less hindered f/ans-olefins may be obtained by reduction with lithium or sodium metal in liquid ammonia or amine solvents (Birch reduction). This reagent, however, attacks most polar functional groups (except for carboxylic acids R.E.A. Dear, 1963 J. Fried, 1968), and their protection is necessary (see section 2.6). 

The intramolecular reaction oF allcenes with various O and N functional groups offers useful synthetic methods for heterocycles[13,14,166]. The reaction of unsaturated carboxylic acids affords lactones by either exo- or endo-cyclization depending on the positions of the double bond. The reaction of sodium salts of the 3-alkenoic acid 143 and 4-alkenoic acid 144 with Li2PdCl4 affords mostly five-membcrcd lactones in 30-40% yields[167]. Both 5-hexe-noic acid (145) and 4-hexenoic acid (146) are converted to five- or six-mem-bered lactones depending on the solvents and bases[168]. Conjugated 2,4-pentadienoic acid (147) is cyclized with Li2PdCl4 to give 2-pyrone (148) in water[i69]. 

Benzoic acid and naphthoic acid are formed by the oxidative carbonylation by use of Pd(OAc)2 in AcOH. t-Bu02H and allyl chloride are used as reoxidants. Addition of phenanthroline gives a favorable effect[360], Furan and thiophene are also carbonylated selectively at the 2-position[361,362]. fndole-3-carboxylic acid is prepared by the carboxylation of 1-acetylindole using Pd(OAc)2 and peroxodisulfate (Na2S208)[362aj. Benzoic acid derivatives are obtained by the reaction of benzene derivatives with sodium palladium mal-onate in refluxing AcOH[363]. 

Solvent Effects on the Rate of Substitution by the S 2 Mechanism Polar solvents are required m typical bimolecular substitutions because ionic substances such as the sodium and potassium salts cited earlier m Table 8 1 are not sufficiently soluble m nonpolar solvents to give a high enough concentration of the nucleophile to allow the reaction to occur at a rapid rate Other than the requirement that the solvent be polar enough to dis solve ionic compounds however the effect of solvent polarity on the rate of 8 2 reactions IS small What is most important is whether or not the polar solvent is protic or aprotic Water (HOH) alcohols (ROH) and carboxylic acids (RCO2H) are classified as polar protic solvents they all have OH groups that allow them to form hydrogen bonds... 

Sodium borohydride is not nearly as potent a hydride donor as lithium aluminum hydride and does not reduce carboxylic acids... 

In the presence of strong bases such as sodium hydroxide carboxylic acids are neutral ized rapidly and quantitatively... 

Metal carboxylates are ionic and when the molecular weight isn t too high the sodium and potassium salts of carboxylic acids are soluble m water Carboxylic acids therefore may be extracted from ether solutions into aqueous sodium or potassium hydroxide... 

The solubility behavior of salts of carboxylic acids having 12—18 carbons is unusual and can be illustrated by considering sodium stearate (sodium octadecanoate) As seen by the structural formula of its sodium salt... 

The formation of micelles and their properties are responsible for the cleansing action of soaps Water that contains sodium stearate removes grease by enclosing it m the hydrocarbon like interior of the micelles The grease is washed away with the water not because it dissolves m the water but because it dissolves m the micelles that are dis persed m the water Sodium stearate is an example of a soap sodium and potassium salts of other C12-C1S unbranched carboxylic acids possess similar properties... 

These equations tell us that the reverse process proton transfer from acids to bicarbon ate to form carbon dioxide will be favorable when of the acid exceeds 4 3 X 10 (pK, < 6 4) Among compounds containing carbon hydrogen and oxygen only car boxylic acids are acidic enough to meet this requirement They dissolve m aqueous sodium bicarbonate with the evolution of carbon dioxide This behavior is the basis of a qualitative test for carboxylic acids... 

Potassium and sodium salts of long chain carboxylic acids form micelles that dissolve grease (Section 19 5) and have cleansing properties The carboxylic acids obtained by saponification of fats are called fatty acids... 

It IS possible to use only one molar equivalent of amine m these reactions if some other base such as sodium hydroxide is present m the reaction mixture to react with the hydro gen chloride or carboxylic acid that is formed This is a useful procedure m those cases m which the amine is a valuable one or is available only m small quantities... 

On shaking an ether solution of a phenol and a carboxylic acid with dilute sodium bicar bonate the carboxylic acid is converted quantitatively to its sodium salt and extracted into the aqueous phase The phenol remains m the ether phase... 

With pA a s of approximately 10 phenols are stronger acids than alcohols but weaker than carboxylic acids They are converted quantitatively to phenoxide anions on treatment with aqueous sodium hydroxide... 

Soaps (Section 19 5) Cleansing substances obtained by the hydrolysis of fats m aqueous base Soaps are sodium or potassium salts of unbranched carboxylic acids having 12-18 carbon atoms... 

Chemically, fluoroacetic acid behaves like a typical carboxylic acid, although its acidity is higher K — 2.2 x 10 ) than the average (9). It can be prepared from the commercially available sodium salt by distillation from sulfuric acid (10). 

The anti-inflammatory agent Oxapro2in, 2-(4,5-diphenyl-2-oxa2ole)propionic acid mono aluminum and dihydroxyalurninum salts, is made by reaction of the sodium salt with aluminum sulfate under controlled conditions (96). Again, the aluminum salts of many carboxylic acid based dmgs are less irritating, ulcerous, and/or toxic, and have a more pleasant taste than their parent acids. 

Isoquinoline can be reduced quantitatively over platinum in acidic media to a mixture of i j -decahydroisoquinoline [2744-08-3] and /n j -decahydroisoquinoline [2744-09-4] (32). Hydrogenation with platinum oxide in strong acid, but under mild conditions, selectively reduces the benzene ring and leads to a 90% yield of 5,6,7,8-tetrahydroisoquinoline [36556-06-6] (32,33). Sodium hydride, in dipolar aprotic solvents like hexamethylphosphoric triamide, reduces isoquinoline in quantitative yield to the sodium adduct [81045-34-3] (25) (152). The adduct reacts with acid chlorides or anhydrides to give N-acyl derivatives which are converted to 4-substituted 1,2-dihydroisoquinolines. Sodium borohydride and carboxylic acids combine to provide a one-step reduction—alkylation (35). Sodium cyanoborohydride reduces isoquinoline under similar conditions without N-alkylation to give... 

Carboxylic Acid Group. Sorbic acid undergoes the normal acid reactions forming salts, esters, amides, and acid chlorides. Industrially, the most important compound is the potassium salt because of stabiUty and high water solubiUty. Sodium sorbate [7757-81-5] (E,E form [42788-83-0]) is less stable and not commercially available. The calcium salt [7492-55-9] which has limited solubiUty, has use in packaging (qv) materials. 

Whereas the carboxylic acid is shown for many of these compounds, the majority of the commercial penicillins are sodium salts. Penicillin G is available as the calcium salt [973-53-5] C gH N20 S d/s Ca, and as the potassium salt [113-98-4] C2gH2yN20 S K. 

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