Aliphatic Monocarboxylic Acids

Compared to aliphatic monocarboxylic acids, aliphatic dicarboxylic acids exhibit a slightly higher affinity toward carbonate-selective stationary phases. The retention behavior of aliphatic dicarboxylic acids such as succinic acid, malonic acid, and oxalic acid is very similar to that of nitrate and sulfate. In contrast to monocarboxylic acids, the retention of aliphatic dicarboxylic acids... 

This is achieved by treatment with aliphatic monocarboxylic acid. 

Such a dispersant formulation for dispersing oil contains a mixture of a sorbitan monoester of an aliphatic monocarboxylic acid, a polyoxyethylene adduct of a sorbitant monoester of an aliphatic monocarboxylic acid, a water-dispersible salt of a dialkyl sulfosuccinate, a polyoxyethylene adduct of a sorbitan triester or a sorbital hexaester of an aliphatic monocarboxylic acid, and a propylene glycol ether as solvent [311,312]. 

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

Fatty acids are long chain aliphatic monocarboxylic acids. 

The major structural units of naturally occurring forms of both simple and complex lipids are the aliphatic, long chain monocarboxylic acids. These are of great importance because of their contribution to the physical and chemical characteristics of the compounds of which they are constituents. In the investigation of the structure of a lipid it may be necessary to determine not only the identity and amount of any fatty acids present but also their position within the molecule. 

You can use analogies to put adipic acid in its right place. Acetic acid is the most important aliphatic monocarboxylic acid adipic is the most important aliphatic dicarboxylic acid. (You remember, of course, that carboxylic is the contraction for carbonyl and hydroxyl, -C-O and -OH, or together, -COOH. Right ) Also, adipic acid is to Nylon 66 what cumene is to phenol. About 95% of the adipic acid ends up as Nylon 66, which is used for tire cord, fibers, and engineering plastics. 

The naphthenic acids in crude oil are primarily monocarboxylic acids possessing an alkylated, cyclopentane single-ring structure. Fused ring, branched aliphatic and dicarboxylic acid compounds are also found in lower numbers. Most species contain 10 carbon atoms, but 20-carbon-atom species have been identified. 

Aliphatic Acids The molecular ion peak of a straight-chain monocarboxylic acid is weak but usually discernible. The most characteristic (sometimes the base) peak is m/z 60 resulting from the McLafferty rearrangement. Branching at the a carbon enhances this cleavage. 

Aliphatic and cycloaliphatic monocarboxylic acids react with sulfur tetrafluoride to give, in general, 1,1,1-trifluoroalkanes as the main products together with considerable amounts of bis(l,1-difluoroalkyl) ethers. Yields of the ethers are related to the nature of the acid and to the reaction conditions. The optimum conditions for the formation of the ethers are dependent on the stability of the ethers towards protolytic cleavage in highly acidic reaction media and on the reactivity of the acids towards sulfur tetrafluoride. 

Esters. The monoisobutyrate ester of 2,2,4-trimethyl- 1,3-pentanediol is prepared from isobutyraldehyde in a Tishchenko reaction (58,59). Diesters, such as trimethylpentane dipelargonate (2,2,4-trimethylpentane 1,3-dinonanoate), are prepared by the reaction of 2 mol of the monocarboxylic acid with 1 mol of the glycol at 150—200°C (60,61). The lower aliphatic carboxylic acid diesters of trimethylpentanediol undergo pyrolysis to the corresponding ester of 2,2,4-trimethyl-3-penten- l-ol (62). These unsaturated esters reportedly can be epoxidized by peroxyacetic acid (63). 

The best preventive measure against racemization in critical synthetic steps (e.g. fragment condensation, see p. 239) is to use glycine (which is achiral) or proline (no azlactone) as the activated carboxylic acid component. The next best choice is an aliphatic monoamino monocarboxylic acid, especially with large alkyl substituents (valine, leucine). Aromatic amino acids (phenylalanine, tyrosine, tryptophan) and those having electronegative substituents in the /7-position (serine, threonine, cysteine) are, on the other hand, most prone to racemization. Reaction conditions that inhibit azlactone formation and racemization are non-polar solvents, a minimum amount of base, and low temperature. If all precautions are taken, one still has to reckon with an average inversion of 1 % per condensation reaction. This means, for example, that a synthetic hectapeptide contains only 0.99100 x 100% = 37% of the fully correct diastereomer (see p. 233 f.). 

The formation of olefines, in the electrolysis of aliphatic monocarboxylic acids, depends, perhaps, not upon an oxidation, process,... 

Fatty Acids and Fatty Alcohols Fatty acids are traditionally meant as aliphatic unbranched monocarboxylic acids, either saturated or unsaturated, but with a chain length of 4 to 28 carbon atoms. Sometimes even shorter acyclic aliphatic carboxylic acids like acetic acid are named fatty acids, although they are not found in oils and fats [19]. 

Fatty acids are aliphatic monocarboxylic acids, many of which occur as esters of glycerin (glycerides) in natural fats and oils. For example, acetic, butyric, propionic, lauric,... 

Aliphatic monocarboxylic acids and their esters generally display a weak but noticeable molecular-ion peak. 

Eatty acids are aliphatic monocarboxylic acids. Over 1000 fatty acids are known with different chain length, positions. 

There are few reports on the use of homogeneous catalysts. H4Ru4(CO)b(PBu3)4 has been used to catalyze the hydrogenation of aliphatic monocarboxylic acids to produce primary alcohols at 180-200 °C and 130 atm. Generally, yields of the primary alcohols were low due to poor conversions (1-44%) and concomitant formation of esters. 

A survey undertaken by Lawless et al (1974) identified 17 dicarboxylic acids (Figure 1) in Murchison including 15 saturated and two unsaturated aliphatic compounds. As with monocarboxylic acids, complete structural diversity was observed. Cronin et al (1993) examined the distribution of hydroxymonocarboxylic acids. 

Aliphatic monocarboxylic acids, C12 to C20. principally palmitic and stearic. 

A successful technique applied for the analysis of humin and humic acids was the pyrolysis with on line methylation followed by GC/MS analysis [6,9]. In one such study [9] humin deashed by treatment with HCI and FIF was pyrolysed and compared to humic acid obtained from the same soil, showing that humin contains larger amounts of carbohydrates and aliphatic compounds. This type of study also revealed the presence in the humin and humic acid pyrolysates of monocarboxylic acids with up to 32 carbon atoms, dicarboxylic acids, methoxymonocarboxylic acids with up to 26 carbon atoms, triterpenoid acids, etc. These compounds were not reported in other studies (e g. [2]) where the chromatographic separation did not allow the detection of compounds difficult to elute due to their high boiling point and polarity. 

The term lipids in this entry is restricted to esters and amides of the long-chain aliphatic monocarboxylic acids, the fatty acids, and to their biosynthetically or functionally related compounds. The most abundant lipids are the esters of fatty acids with glycerol (1,2,3-trihydroxypropane), denoted as glycerolipids. Lipids are classified according to the number of hydrolytic products per mole. Simple (or neutral) lipids release two types of products (e.g., fatty acids and glycerol). 

Figure 6.- Total Ion Chromatogram of the thermal degradative products obtained after pyrolysis of the HA isolated from the Konin (Poland) brown coal in the presence ot TMAH. Key labels for aromatic compunds are (9) 4-memoxybenzenecarboxylic acid methyl ester, (14) benzenedicarboxylic acid dimethyl ester, (16) 3,4-dimelhoxybenzenecarboxylic acid methyl ester, (17) 3,4-dimethoxybenzeneacetic acid methyl ester, (18) 4-medioxycinnamic acid methyl ester, (19) 3,4,5-trimethoxy-l-ethylbenzene. Key labels for aliphatic compounds are (Cn) monocarboxylic acid methyl esters, (Cn l) unsaturated monocarboxylic acid methyl esters, (Cn) dicarboxylic acid dimethyl esters.

The list of acids isolated from aqueous extracts of the shale is given for comparison. These acids were identified in the water extracts from raw Aleksinac shale as well as from bitumen-free shale, i.e., before and after the extraction of the bitumen (21). Mass spectrometric identifications of various isomers were based on comparison of the relative intensities of molecular ions and their corresponding base peak ions. The compounds extracted with water from the bitumen-free shale were very similar to the compounds isolated from the raw shale. The findings suggest that the acids were present as salts in both instances. In the aqueous extracts aromatic and dicarboxylic acids predominated, while aliphatic monocarboxylic acids were absent. Comparison of the chemical nature of water extractable acids with the acids obtained from the bitumen of the same shale showed a similarity in the type and range of aromatic and saturated unbranched dicarboxylic acids. 

A sufficient separation of all these compounds, therefore, is only achieved by using two AS4 columns in series. However, the separation of the two stereoisomers, maleic acid and fumaric acid, is much easier. It is obtained under standard conditions and is shown in Fig. 3-87. In contrast to monocarboxylic acids, the retention of aliphatic dicarboxylic acids increases with decreasing pK value. The corresponding data are summarized in Table 3-20. This finding is explained by the charge-stabilizing effect exerted by the +1-effect of the methylene groups which decreases from succinic acid to oxalic acid ... 

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