Carboxylic acids 334 INDEX

Physical Data Index 4H-Azepine-2-carboxylic acid... 

For acrylate polymers with higher levels of carboxylic acids, THF can be modified by the addition of acids such as acetic, phosphoric, or trifluoroacetic. Levels as high as 10% acetic acid are considered acceptable by most manufacturers for their styrene/DVB columns. If such a modified mobile phase is used, it may need to be premixed rather than generated using a dynamic mixing HPLC pump because on-line mixing often leads to much noisier baselines, particularly when using a refractive index detector. 

Eor amine-containing polymers, DMF is often a good choice of solvent. DMF can also be a good choice for polymers of higher carboxylic acid content. However, DMF does present some experimental difficulties. It must be run at an elevated temperature, typically 60°C, because of its viscosity. Also, because most polymers have a much lower refractive index response in DMF, the signal-to-noise ratio for a polymer in this solvent is diminished versus the same ratio for common acrylates in THF. 

Entries where the oxidation state of a metal has been specified occur after all the entries for the unspecified oxidation state, and the same or similar entries may occur under both types of heading. Thus cyanide appears under Chromium complexes, Chromium(O) complexes, Chromium(I) complexes, etc. More specific entries, such as Chromium, hexacyano-, may also occur. Similar ligands may also occur in different entries. Thus a carboxylic acid-metal complex may occur under Carboxylic acid complexes, under entries for specific carboxylic acids, and under the specific metal. Coordination complexes may also be listed in the Cumulative Formula Index. 

In an alternate synthesis, the formation of thermoplastic vulcanizate (TPV) is accomplished with two polymers, wherein one polymer is grafted with a carboxylic acid anhydride, which then is reacted with an aminosilane, which reacts with the acid anhydride and then cross-links with moismre. The vulcanizates exhibit good mechanical properties and lower melt-flow index than the starting polymers. 

How to Use the Book to Locate Examples of the Preparation of Protection of Monofunctional Compounds. Examples of the preparation of one functional group from another are found in the monofunctional index on p. x, which lists the corresponding section and page. Sections that contain examples of the reactions of a functional group are found in the horizontal rows of this index. Section 1 gives examples of the reactions of alkynes that form new alkynes Section 16 gives reactions of alkynes that form carboxylic acids and Section 31 gives reactions of alkynes that form alcohols. 

Examples of alkylation, dealkylation, homologation, isomerization, and transposition are found in Sections 1,17,33, and so on, lying close to a diagonal of the index. These sections correspond to such topics as the preparation of alkynes from alkynes carboxylic acids from carboxylic acids and... 

Examples of the protection of alkynes, carboxylic acids, alcohols, phenols, aldehydes, amides, amines, esters, ketones, and alkenes are also indexed on p. xvii. Section (designated with an A 15A, 30A, etc.) with protecting group reactions are located at the end of pertinent chapters. 

Oxidative damage to membrane polyunsaturated fatty acids leads to the formation of numerous lipid peroxidation products, some of which can be measured as index of oxidative stress, including hydrocarbons, aldehydes, alcohols, ketones, and short carboxylic acids. 

These oxidations suffer from the fact that the high selectivities are only observed at low conversions (<7%). At higher conversions, the carboxylic acid products leach the transition metals out of the zeolite framework into solution where the selectivity index is much lower [63]. As these reactions proceed, the 3 -I- oxidation states of the metal ions return to their 2 -I- states, accompanied by their characteristic color change. In the case of MnAlPO-18, the spent catalyst (Mn ) was washed with methanol and reactivated in dry air at 550°C and successfully recycled (Mn Mn ) twice without appreciable loss of activity [64]. 

The Surlyn A ionomers (E. I. du Pont de Nemours Co.) are believed to be derived from copolymers of ethylene with minor amounts of methacrylic acid which are treated subsequently, so that substantial amounts of the carboxylic acid are converted to the sodium or other metal carboxylate. Resins similar to the one studied in this work contain about 10 weight % methacrylic acid. The ash (sodium carbonate) indicates about 40% neutralization. This resin, which contains 0.05% Santo-white Powder (Monsanto Chemical Co.), a phenolic antioxidant, is of medium molecular weight—i.e., probably corresponding to an ethylene homopolymer with a melt flow index around 20 (17). The molecular weight distribution is broad (17). 

Many carboxylic acids exist in the free state as hydrogen-bonded dimers with an oxygen-oxygen separation (between oxygens linked to the same carbon atom) close to 220 pm. Replacement of these hydrogens by two metal atoms results in the close approach of the two metal atoms.28 Much of the interest in these dinuclear paddlewheel systems has been generated by a need to understand the nature of these metal-metal interactions. The natural desire of chemists is to use formal bond orders as an index of this interaction and much has been published to this end. However, there are growing indications that such a formal concept is not entirely appropriate for such systems.29... 

Table V is also an index to Table I it classifies the compounds according to the functional groups they contain. One frequently wants to examine data on carbonyl compounds, on unsaturated or halogenated ketones, or another more or less specific class of substances, and the purpose of Table V is to simplify searches of this sort. Pyruvic acid appears in Table V both among the ketones and among the carboxylic acids, and Inspection of either group would quickly reveal any closely related compound that appears in this volume.

The dielectric constant varies with coal rank (Chatterjee and Misra, 1989). The theorem that the dielectric constant is equal to the square of the refractive index (which is valid for nonconducting, nonpolar substances) holds only for coal at the minimum dielectric constant. The decreasing value of dielectric constant with rank may be due to the loss of polar functional groups (such as hydroxyl or carboxylic acid functions), but the role of the presence of polarizable electrons (associated with condensed aromatic systems) is not fully known. It also appears that the presence of intrinsic water in coal has a strong influence on the dielectric properties (Chatterjee and Misra, 1989). 

Examination of the molecular formula C14H2602 reveals that the compound has an index of hydrogen deficiency of 2. Because we are told that the compound is a carboxylic acid, one of these elements of unsaturation must be a carbon-oxygen double bond. The other must be a carbon-carbon double bond because the compound undergoes cleavage on ozonolysis. Examining the products of ozonol-ysis serves to locate the position of the double bond. 

The experimental verification of the theoretical predictions for reversible and quasi-reversible behavior can be seen in Fig. 7.49, where the Qsw — E index curves (symbols) are plotted corresponding to the di-electronic reduction of the system Anthraquinone-2-carboxylic acid (2-AQCA) 10 pM in HCIO4 1.0 M. These curves have been obtained for different values of the square wave pulse amplitude and for two values of the pulse time length t 5 (reversible, Fig. 7.49a, b) and 0.5 ms (quasi-reversible, Fig. 7.49c, d). 

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