Acid and its Derivatives

The development of a satisfactory DHA synthesis has been hampered by the problems of over-oxidation and also by the limited stability of DHA in aqueous solution. T o date, DHA has been obtained only as a viscous syrup or amorphous solid. A convenient preparative method involves oxidation by molecular oxygen using a catalyst of activated charcoal dispersed in aqueous ethanol. The DHA product is reasonably stable at low temperature (— 10 C). A dimeric form of DHA, bisdehydroascorbic acid (or BDHA), is also known. This substance is isolatable in crystalline form and may be obtained from DHA by dissolving the latter in nitromethane, boiling the solution and 

The stable dimer BDHA dissociates in aqueous solution to DHA but is not, in fact, particularly water soluble. 

---

Folic acid and its derivatives (mostly the tri-and heptaglutamyl peptides) are widespread in nature. It is a specific growth ctor for certain micro-organisms, but in animals the intestinal bacteria provide the small quantities needed for growth. The coenzyme forms are actually... 

It is the parent substance of a group of compounds which includes cytosine, thymine and uracil, which are constituents of nucleic acids and barbituric acid and its derivatives, which are important medicinally. 

Thermal electrocyclizations of perhalogenated 1,3-butadienes yield perhalogenated cyclobutenes which can be solvolysed to 3,4-dihydroxy-3-cydobutene-l,2-dione ( squaric acid") and its derivatives (G. Maahs, 1966 H. Knorr, 1978 A.H. Schmidt, 1978). Double CO extrusion from fused cyclobutenediones has been used to produce cycloalkynes, e.g., benzyne from benzocyclobutenedione by irradiation in an argon matrix (O.L. Chapman, 1973) and cyc/o-Ci8, cyclo-Cn, etc. by laser desorption mass spectroscopy of appropriate precursors (see section 4.9.8). 

Several excellent review articles (28—31) cover the chemistry of the acid and its derivatives in great detail. Trifluoromethanesulfonic acid is available from the 3M Co. as Fluorochemical Acid FC-24 the lithium salt is available as Fluorochemical Specialties FC-122, FC-123, and FC-124 (32). 

Physical Properties. Pure, anhydrous lactic acid is a white, crystalline soHd with a low melting poiat. However, it is difficult to prepare the pure anhydrous form of lactic acid generally, it is available as a dilute or concentrated aqueous solution. The properties of lactic acid and its derivatives have been reviewed (6). A few important physical and thermodynamic properties from this reference are summarized ia Table 1. 

Many of the physical properties are not affected by the optical composition, with the important exception of the melting poiat of the crystalline acid, which is estimated to be 52.7—52.8°C for either optically pure isomer, whereas the reported melting poiat of the racemic mixture ranges from 17 to 33°C (6). The boiling poiat of anhydrous lactic acid has been reported by several authors it was primarily obtained duriag fractionation of lactic acid from its self-esterification product, the dimer lactoyUactic acid [26811-96-1]. The difference between the boiling poiats of racemic and optically active isomers of lactic acid is probably very small (6). The uv spectra of lactic acid and dilactide [95-96-5] which is the cycHc anhydride from two lactic acid molecules, as expected show no chromophores at wavelengths above 250 nm, and lactic acid and dilactide have extinction coefficients of 28 and 111 at 215 nm and 225 nm, respectively (9,10). The iafrared spectra of lactic acid and its derivatives have been extensively studied and a summary is available (6). 

Uses. Currentiy, the principal use of lactic acid is in food and food-related applications, which in the United States accounts for approximately 85% of the demand. The rest ( 15%) of the uses are for nonfood industrial applications. The expected advent of the production of low cost lactic acid in high volume can open new applications for lactic acid and its derivatives, because it is a versatile molecule that can be converted to a wide range of industrial chemicals or polymer feedstocks (1,6,20). 

Naphthenic acids have been the topic of numerous studies extending over many years. Originally recovered from the petroleum distillates to minimise corrosion of refinery equipment, they have found wide use as articles of commerce in metal naphthenates and other derivatives. A comprehensive overview of the uses of naphthenic acid and its derivatives can be found in References 1 and 2. A review of the extensive research on carboxyUc acids in petroleum conducted up to 1955 is available (3), as is a more recent review of purification, identification, and uses of naphthenic acid (4). 

Free thiocyanic acid [463-56-9] HSCN, can be isolated from its salts, but is not an article of commerce because of its instabiHty, although dilute solutions can be stored briefly. Commercial derivatives of thiocyanic acid are principally ammonium, sodium, and potassium thiocyanates, as weU as several organic thiocyanates. The chemistry and biochemistry of thiocyanic acid and its derivatives have been reviewed extensively (372—374). 

A. A. Newman, ed.. Chemistry andPiochemisty ofThioyanic Acid and Its Derivatives, Academic Press, Inc., New York, 1975. 

Nicotinyl alcohol (3-pyridinylcarbinol, 3-pyridinemethanol) (27) has use as an antilipemic and peripheral vasodilator. It is available from either the reductions of nicotinic acid esters or preferably, the reduction of the nitrile to the amine followed by dia2otation and nucleophilic displacement. It is frequently adininistered in the form of the tartrate (Eig. 7). Nicotinic acid is frequently used as a salt in conjunction with basic dmgs such as the peripheral vasodilator xanthinol niacinate (28). Nicotinic acid and its derivatives have widespread use as antihyperlipidemic agents and peripheral vasodilators (1). 

A process to convert butenes to acetic acid has been developed by Farbenfabriken Bayer AG (137) and could be of particular interest to Europe and Japan where butylenes have only fuel value. In this process a butane—butylene stream from which butadiene and isobutylene have been removed reacts with acetic acid in the presence of acid ion-exchange resin at 100—120°C and 1500—2000 kPa (about 15—20 atm) (see Acetic acid and its derivatives, acetic acid). Both butenes react to yield j -butyl acetate which is then oxidized at about 200°C and 6 MPa (about 60 atm) without catalyst to yield acetic acid. 

Acetaldehyde Cyanohydrin. This cyanohydrin, commonly known as lactonitnle, is soluble in water and alcohol, but insoluble in diethyl ether and carbon disulfide. Lactonitnle is used chiefly to manufacture lactic acid and its derivatives, primarily ethyl lactate. Lactonitnle [78-97-7] is manufactured from equimolar amounts of acetaldehyde and hydrogen cyanide containing 1.5% of 20% NaOH at —10 20 ° C. The product is stabili2ed with sulfuric acid (28). Sulfuric acid hydroly2es the nitrile to give a mixture of lactic acid [598-82-3] and ammonium bisulfate. 

Acetone Cyanohydrin. This cyanohydrin, also known as a-hydroxyisobutyronitnle and 2-methyUactonitrile [75-86-5], is very soluble in water, diethyl ether, and alcohol, but only slightly soluble in carbon disulfide or petroleum ether. Acetone cyanohydrin is the most important commercial cyanohydrin as it offers the principal commercial route to methacrylic acid and its derivatives, mainly methyl methacrylate [80-62-6] (see Methacrylic acid AND derivatives). The principal U.S. manufacturers are Rohm and Haas Co., Du Pont, CyRo Industries, and BP Chemicals. Production of acetone cyanohydrin in 1989 was 582,000 metric tons (30). 

Anthraquinone-l-sulfonic acid and Its Derivatives. Anthraquinone-l-sulfonic acid [82-49-5] (16) has become less competitive than 1-nitroanthraquinone as the intermediate for 1-aminoanthraquinone. However, it still has a great importance as an intermediate for manufacturing vat dyes via 1-chloroanthraquinone. 

The influence of NH., and CO, on the chromatographic behaviour of benzoic acid and its derivatives (o-, m-, p-hydroxybenzoic, nitrobenzoic, aminobenzoic, chlorobenzoic acids) was studied. The work was carried out by means of upgoing TLC on Sorbfil plates. Isopropanol- and ethyl acetate-containing water-organic eluents were used as mobile phases in the absence or presence of gaseous modifiers in the MP. The novel modification of TLC has been found to separate benzoic acids with different values of their dissociation constants more effectively than water-organic mobile phases. 

Acetic Acid and Its Derivatives, edited by Victor H. Agreda and Joseph R. Zoeller... 

The Fiesselmann reaction has been extensively used with p-halovinyl esters, ketones,aldehydes and nitriles as reaction partners for thioglycolic acid and its derivatives. This reaction with P-halovinyl aldehydes has been extensively explored as a result of the availability of P-chloro-a,P-unsaturated aldehydes via the Vilsmeier... 

Polymalatase may be useful for the tayloring of /3-poly(malic acid) and its derivatives, and for analytical purposes. If the hydrolase is arrested at points of polymer branches or covalently/physically attached ligands, the hydrolase can be used in studies analogous to those known for DNA and exonucleases. 

In order to obtain information regarding the composition of these degradation products, aqueous extracts of the lead soaps of the linseed oil fatty acids were analysed, mainly by chromatography. The extracts contained formic acid 46%, azelaic acid 9% and pelargonic acid and its derivatives 27%, the remaining 18% consisting of a mixture of acetic, propionic, butyric, suberic, pimelic and adipic acids. It was shown that whereas the salts of formic acid were corrosive, those of azelaic and pelargonic acid were very efficient inhibitors. 

Phosphonic acid and its derivatives Various alcohols and diacids 40,166... 

Maleate chemistry has proved to be an enduring mainstay of many water treatment formulations, primarily as non-phosphate-containing calcium carbonate scale inhibitors. For most water treatment applications, polymaleic acid and its derivatives offer a good alternative to phosphonate chemistries, when required. 

Cationic polymerization of cyclosiloxanes is well known but used much less frequently than anionic reactions. The most widely used catalysts include sulfuric acid and its derivatives, alkyl and aryl sulfonic acids and trifluoroacetic acid1 2,1221. Due to their ease of removal, in industrial applications acid catalysts are generally employed on supports such as bentonite clay or Fuller s earth. 

Malonic acid and its derivatives, which would give four-membered cyclic anhydrides, do not give this reaction when heated but undergo decarboxylation (12-38) instead. 

Figure 14-8. Phosphatidic acid and its derivatives. The 0 shown shaded in phosphatidic acid is substituted by the substituents shown to form in (A) 3-phosphatidylcholine, (B) 3-phosphatidylethanolamine,...

---