Amination methods, comparison

In the following examples, a primary analytieal test method was used to measure HALS 3 coneentrations in LLDPE natural and color coneentrate. The primary method utilized in this evaluation was a total base titration of the extracted hindered amine. A comparison of the ex-peeted values, primary analytical results and NIR measured values are presented in Tables 3 4. 

Diazotization involves drawing a known volume of atmospheric air through an absorbent solution, hydrolyzing the isocyanate to amine, diazotization and coupling this amine, and comparison of colour formation with a range of standards. The method varies in detail with the specific isocyanate being determined. 

The use of microwave irradiation for this reaction, compared to conventional thermal heating, was investigated. Chloroform used as solvent under the conventional heating did only allow a temperature of 60 °C and a direct comparison between the two methods is therefore somewhat unfair imder these circumstances. Nevertheless, the microwave-assisted method is attractive and proved useful for both primary and secondary amines resulting in highly substituted pyrazolo ring-fused pyridones 40 in 68-86% yields within only 10 min. 

As a result of Eq. (11) we are able to calculate the chemical potential of any molecule X in any liquid system S, relative to the chemical potential in a conductor, i.e. at the North Pole. Hence, COSMO-RS provides us with a vehicle that allows us to bring any molecule from its Uquid state island to the North Pole and from there to any other liquid state, e.g. to aqueous solution. Thus, given a liquid, or a reasonable estimate of AGjis of a soUd, COSMO-RS is able to predict the solubility of the compound in any solvent, not only in water. The accuracy of the predicted AG of transfer of molecules between different Uquid states is roughly 0.3 log units (RMSE) [19, 22] with the exception of amine systems, for which larger errors occur [16, 19]. Quantitative comparisons with other methods will be presented later in this article. 

Aliphatic amides possess more strong a-C—H bonds in comparison with amines. This is the result of the carbonyl group influence on the stabilization of the formed a-amidoalkyl radical formed from amide in the reaction with the peroxyl radical. This influence is not so strong as that of the amine group. The values of the a-C—H bond in a few amides were estimated recently by the IPM method [4] and are given here. 

The comparison of the rate constants of these reactions with BDE of N—H bonds proves that the higher the BDE, the lower rate the constant. The rate constants of the reaction of amine with hydroperoxide calculated by the IPM method are listed in Table 15.18. The parameters of these reactions are given in Table 15.18. The values of activation energies for all reactions of the type... 

Mah, G., Reilly, R. M., Wong, G. L. and Houle, S. A comparison of three methods to determine the radiochemical purity of 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO). Nucl. Med. Commun. 10 733-740,1989. 

It seems reasonable that polyester cyclics could be prepared by an extension of the /wendo-high-dilution [17] chemistry used for the preparation of cyclic carbonate oligomers [18, 19] however, such proved not to be the case. Brunelle et al. showed that the reaction of terephthaloyl chloride (TPC) with diols such as 1,4-butanediol did not occur quickly enough to prevent concentration of acid chlorides from building up during condensation [14]. Even slow addition of equimolar amounts of TPC and butanediol to an amine base (triethylamine, pyridine or dimethylaminopyridine) under anhydrous conditions did not form cyclic oligomers. (The products were identified by comparison to authentic materials isolated from commercial PBT by the method of Wick and Zeitler [9].)... 

A comparison of extraction methods for primary aromatic amines including 1,4-phenylenediamine, 2,4-diaminotoluene, benzidine, 4,4 -methylenebis (2-chloroanilme), 3,3 -dimethylbenzidine, and 3,3 -dichlorobenzidine from solid matrices was conducted. Supercritical fluid extraction (SEE) was evaluated and compared with the classical method, sonication extraction (Oost-dyk et al., 1993). 

Figure 2.8, is generated, presenting peaks correspondent to functional groups, such as epoxide, primary and secondary amines, and hydroxyl. The values of the absorption bands for these groups can be found in the papers referenced earlier. The basic principle of all these methods is the comparison between the spectrum of reference substances and spectra of the reactants and products of a curing reaction subjected to radiation. A qualitative and quantitative identification of the components is then possible. 

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