Higher carboxyhc acids

Fluotinated higher carboxyHc acids, Perfluoroalkanesulfonic acids,... 

Primary and secondary alkyl halides may be converted to the next higher carboxyhc acid by a two-step synthetic sequence involving the preparation and hydrolysis of nitriles. Nitriles, also known as alkyl cyanides, are prepared by nucleophilic substitution. 

Formic acid exhibits many of the typical chemical properties of the aHphatic carboxyHc acids, eg, esterification and amidation, but, as is common for the first member of an homologous series, there are distinctive differences in properties between formic acid and its higher homologues. The smaller inductive effect of hydrogen in comparison to an alkyl group leads, for example, to formic acid = 3.74) being a considerably stronger acid than acetic acid... 

The Guerbet reaction can be used to obtain higher alcohols 2-propyl-1-heptanol [10042-59-8] from 1-pentanol condensation and 6-methyl-4-nonanol from 2-pentanol (80—83). Condensations with alkah phenolates as the base, instead of copper catalyst, produce lower amounts of carboxyhc acids and requke lower reaction temperatures (82,83). The crossed Guerbet reaction of 1-pentanol with methanol in the presence of sodium methoxide catalyst afforded 2-heptanol in selectivities of about 75% (84). 

The extraction of metal ions depends on the chelating ability of 8-hydroxyquinoline. Modification of the stmcture can improve its properties, eg, higher solubility in organic solvents (91). The extraction of nickel, cobalt, copper, and zinc from acid sulfates has been accompHshed using 8-hydroxyquinohne in an immiscible solvent (92). In the presence of oximes, halo-substituted 8-hydroxyquinolines have been used to recover copper and zinc from aqueous solutions (93). Dilute solutions of heavy metals such as mercury, ca dmium, copper, lead, and zinc can be purified using quinoline-8-carboxyhc acid adsorbed on various substrates (94). 

Polyester polyols are based on saturated aHphatic or aromatic carboxyHc acids and diols or mixtures of diols. The carboxyHc acid of choice is adipic acid (qv) because of its favorable cost/performance ratio. For elastomers, linear polyester polyols of ca 2000 mol wt are preferred. Branched polyester polyols, formulated from higher functional glycols, are used for foam and coatings appHcations. Phthalates and terephthalates are also used. 

In addition to copolymerisation, polyethylenes terrninated as ketones, alcohols, and carboxyHc acids with molecular weights as high as 700 daltons are now available. The products offer the same chemical functionaHty as common fatty alcohols and acids, but are higher melting and harder. Similar to the fatty alcohols and acids, derivatives such as ethoxylates, esters, and amides also are available as higher melting versions of the fatty derivatives. 

Worldwide capacity for production of higher aHphatic carboxyHc acids (predominantiy C8—C18), commonly called fatty acids, is about 3.5 million metric tons, with an additional 400,000 metric tons because of start-up over the next 1—2 years, mostiy in southeast Asia. Worldwide production of these higher (and linear) fatty acids in 1988 was estimated at 2.6 million metric tons, with annual growth estimated at 2—3% (8). U.S. production of these C8—C18 linear acids, including tall oil (9), was reported to be approximately 660,000 metric tons, a figure that would appear to be understated. The use of these fatty acids covets many consumer product and industrial appHcations and historically has correlated well with the GNP in the United States. 

Reduction of Carboxylic Acids to Alcohols. In addition to the nonsupported catalysts mentioned for the hydrogenation of amides to amines, mthenium and rhenium on alumina can be used to reduce carboxyHc acids to alcohols. The conditions for this reduction are somewhat more severe than for most other hydrogenation reactions and require higher temperatures, >150° C, and pressures, >5 MPa (725 psi) (55). Various solvents can be used including water. 

The Arndt-Eistert synthesis allows for the conversion of carboxyhc acids 1 into the next higher homolog 4. This reaction sequence is considered to be the best method for the extension of a carbon chain by one carbon atom in cases where a carboxylic acid is available. 

IG and added in the free energy of solvation in DMSO computed with PCM at HF/6-31-l-G(d,p). The lowest energy TS is for the carboxyhc-acid-catalyzed enamine route (Scheme 6.8 D). This barrier is 10.7 kcal mol smaller than that for the barrier without proline acting as a catalyst. The transition state for the enaminium-catalyzed route (Scheme 6.8 B) is 29.0 kcal mol higher than the TS for Scheme 6.8 D. All attempts to locate a TS for the nucleophilic substitution route (Scheme 6.8 A) failed. However, the carbinolamine intermediate that proceeds the TS on path A lies 12.7 kcal mol above the TS for Scheme 6.8... 

Polycarboxylic Acids. Carboxylic acids have been found to bind strongly to actinide ions. The primary binding mode for the carboxyhc acids is bidentate. The affinity of the low-valent actinides with these ligands increases with the density of the hgand, for example, ethy lenediaminetetraacetate (EDTA) > acetate. For An" +, the EDTA ligand is hexadentate with a twist conformation. Diethylenetriaminepentaacetate (DTPA) has an even higher affinity for both An + and An + ions. 

The films plasticized with AA-based polyesters also showed much higher levels of polyester enrichment at the surface than films plasticized with DMA-based polyesters, which indicates better miscibihty between PVC and polyesters containing methyl ester end-groups. Stronger interactions between plasticizer and matrix and less attractive interactions with water make methyl ester end-groups less inchned to be extracted by aqueous media than species with carboxyhc acid end-groups. Methyl ester end-groups also have a stabi-... 

Treatment of these samples with SF4 gas to convert the carboxyhc acids produced in the weathering process into carbonyl fluorides showed [2, 11] that the acids are actually a mixture of aliphatic and aromatic acids (Figure 18.12). Aromatic acid species are by far die predominant ones, however. The origin of these acids will be discussed below in conjunction with the overall mechanisms of photodegradation. Aliphatic acid species were detected by GC/MS in the artificial device exposure of PECT [11]. Note that the PECT copolymer produced more aromatic acids with the same exposure as PET but that the aliphatic acid production was several times higher for the PECT copolymer. The photo-oxidation of the co-glycol must be the reason for this difference. 

Similar to the interactions of low-molecular-weight carboxyhc acids with hair, the interactions of low-molecular-weight organic bases involve more than simply the back-titration of conjugate acids. Barnett [128] has described the interaction of mono-, di-, and triethanol amines at 25% concentration and higher with human hair (see Table 5-20). The reactions of these species with hair involve extensive swelling and ultimately lead to decomposition and disintegration of the hair. 

Monolayers with much higher coverage were reported to form from the fi-aminocyclodextrin derivative containing only one disulphide-terminated alkane chain attached to the amino group of the 6-deoxyaminoglucose unit. These layers were shown to bind naphthalenesulphonic acids" ". A similar monolayer selectively binds a trans-azobenzene derivative" " . /3-Cyclodextrin modified layers also show selective transport of ferrocene carboxyhc acid and hydroxyquinone. The selective transport can be controlled by blocking the /3-cyciodextrin cavities with some guest molecules such as cyclohexanol, borneol and ursodeoxycholic acid . ... 

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