Carboxylic aliphatic

In order to elucidate the mechanism of adhesion of ionomer-carboxylate cements, Wilson and his coworkers have carried out several studies on the adsorption of carboxylates - aliphatic, aromatic and polymeric-on hydroxyapatite (Skinner et al., 1986 Scott, Jackson Wilson, 1990 Ellis et al., 1990). 

The 13C NMR study utilized cross polarization-magic angle spinning (CP-MAS) with spin counting. The elemental and functional group analyses provided input for a series of analytical constraints calculations that yield an absolute upper limit for the amount of aromatic carbon and most probable estimates of both aromatic and non-carboxyl aliphatic carbon in each sample. Spin counting experiments demonstrate that less than 50% of the... 

In conclusion, DOM in water is a complex mixture of degraded moderate-sized biomolecules. As degradation proceeds in the aquatic environment, carbohydrates and lignin degradation products disappear within days to a few years. Only the carboxylated aliphatic alicyclic component persists for thousands of years in the marine environment (35) or in isolated lake environments like Big Soda Lake, Nevada. 

As a model experiment to see the effect of orthoesters in reducing the content of terminal carboxyl, aliphatic long-chain dicarboxylic acid and a large excess of various additives reacted in biphenyl at 250°C, and the rate constants of the pseudo-first-order reaction were compared. The reaction rate constant decreases in the order of tetraphenyl... 

Experimental J(C-C) values are available for some 13C-carboxyl aliphatic carboxylic acids. (51) /(C0-C) varies between 54-4 and 59-2 Hz. The authors conclude that factors other than ring strain are important in giving rise to this variation in /(C0-C). 7(C0-C) values in the C=C-C-C02H fragment (52) also fall within the range of values given above. 

Fatty acids are known by several names volatile fatty acids from Ci to C5, fatty acids from Cg to C24, long-chain fatty acids from C25 to C40, and very long chain fatty acids above C40. One can also find other names in the chemical nomenclature. The correct name for this group of carboxylic aliphatic acids (with or without any additional functions) is simply. 

In common with the other humic substances, many of the properties of HA are due to the nature of its functional groups. These include carboxyl, aliphatic and aromatic hydroxyl, carbonyl and amide groups which can be readily detected by infrared spectroscopy. The results obtained by chemical methods of functional group analysis are often difficult to interpret and may be contradictory. This in part is due to the presence of similar functional groups in the non-humic components ("impurities ) which are extracted along with the humic substances. 

Kolbe reaction The pre >aration of saturated or unsaturated hydrocarbons by the electrolysis of solutions of the alkali salts of aliphatic carboxylic acids. Thus, ethanoic acid gives ethane,... 

Hofmann s amine synthesis can be applied to both aliphatic and aromatic carboxylic acid amides, benzamide, C HsCONH, thus giving aniline, C4H5NH,. 

When an aromatic compound having an aliphatic side chain is subjected to oxidation, fission of the side chain occurs between the first and second carbon atoms from the benzene ring, the first carbon atom thus becoming part of a carboxyl ( -COOH) group. For example ... 

A) Amino-aliphatic carboxylic acids. Glycine, tyrosine cystine. ... 

The aliphatic acids are all soluble in cold water. The aromatic acids are very sparingly soluble in cold water, but readily soluble in boiling water. Phthalic acid, having two carboxyl groups, is more soluble than the other aromatic acids in cold water. 

A) AMINO-ALIPHATIC CARBOXYLIC ACIDS. Glycine, tyrosine, cystine. 

Amino Aliphatic Carboxylic Acids. 3,5-Dinitrobenzoyl derivatives (p. 381), Benzoyl derivatives (p. 382), Sulphonyl derivatives (p. 382). 

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... 

ACID ANHYDRIDES OF ALIPHATIC CARBOXYLIC ACIDS Acid anhydrides of monobasic aliphatic acids may be prepared —... 

The conversion of an aliphatic carboxylic acid into the a-bromo- (or a-chloro ) acid by treatment with bromine (or chlorine) in the presence of a catal3rtic amount of phosphorus tribromide (or trichloride) or of red phosphorus is known as the Hell-Volhard-Zelinsky reaction. The procedure probably involves the intermediate formation of the acyl halide, since it is known that halogens react more rapidly with acyl haUdes than with the acids themselves ... 

Aromatic carboxylic acids are usually crystalline sohds, bum with a smoky flame, and are generally sparingly soluble in water. They may be detected and characterised as already described under Aliphatic Carboxylic Acids (Section 111,85). 

When an alkyl aryl ketone is heated with yellow ammonium polysulphide solution at an elevated temperature, an aryl substituted aliphatic acid amide is foimed the product actually isolated is the amide of the ci-aryl carboxylic acid together with a smaller amount of the corresponding ammonium salt of the oarboxylio acid. Thus acetophenone affords phenylacetamide (50 per cent.) and ammonium phenylacetate (13 per cent.) ... 

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