Reactivity characteristics

Iron Blue. There are three common varieties of iron blue MUoti, Chinese, and Pmssian (they are sometimes caUed toning blues). The three types differ chiefly in color, ease of dispersion, and reactivity characteristics. MUori blues are the easiest to disperse and are the least reactive. They are reddest in mass tone (plum colored) in tints, they ate intense and intermediate in redness between the Chinese and Pmssian varieties. Both the Chinese and Pmssian blues are jet in mass tone, but Pmssian blue is considerably redder and less intense in tint than Chinese blue. Because of their jet mass tones, both are used to shade blacks. Pmssian blues are the hardest to disperse and are somewhat more reactive than Chinese blues. 

This numbering system is especially useful since all the reactivity characteristics summarized above can be recognized just from the name of the compound. Resonance activation of the leaving group (Le) for alkoxylation or alkylamination has the following observed characteristics (Section IV, A, 2) ... 

The relation 381 > 382 > 383 is arrived at by an extension of the observed reactivity characteristics to triazanaphthalenes. The poorly activating 4-Le-8-aza relation in 385 and the greater inductive... 

Covalent addition of solvent or of nucleophile prior to substitution will alter the reactivity characteristics of the substrate. Covalent addition of nucleophile after substitution will affect the kinetics in a way similar to the formation of 389. Covalent hydration and additions are especially likely to occur in bicyclic azines. (cf. Section IV,B,3,b).ii>i o>i i i4... 

As a result, we could open the door to a new frontier in indole chemistry. Various 1-hydroxyindoles (4a), l-hydroxytryptophans(la), 1-hydroxytryptamines (lb), and their derivatives have been given birth for the first time. As predicted, 1-hydroxytryptophan and 1-hydroxytryptamine derivatives are found to undergo previously unknown nucleophilic substitution reactions. In addition, we have been uncovering many interesting reactivities characteristic of 1-hydroxyindole structures. From the synthetic point of view, useful building blocks for indole alkaloids, hither to inaccessible by the well-known electrophilic reactions in indole chemistry, have now become readily available. Many biologically interesting compounds have been prepared as well. 

As noted in the previous review (99H1157), we proposed a working hypothesis that 1-hydroxyindoles are classified into two groups from the point of reactivity characteristics toward 85% HCOOH (Scheme 34). Thus, type 1 compounds 227... 

In this section, the emphasis is on carbocation reactions that modify the carbon skeleton, including carbon-carbon bond formation, rearrangements, and fragmentation reactions. The fundamental structural and reactivity characteristics of carbocations toward nucleophilic substitution were explored in Chapter 4 of Part A. 

During the course of related work, we identified the extent to which such metal clusters can take up CO through coordination reactions. The work not only shed light on the details of the coordination reactions, but also provided insight into the electronic and reactive characteristics of the metal clusters themselves. The useful-... 

Only a relatively few reactive systems (Table 7.1) have met these requirements sufficiently well to become commercially established in a significant segment of the market for reactive dyes. In addition to these important types, several others have been marketed [3,11] as alternative ranges that have failed to maintain a foothold in the marketplace, or as individual members of established ranges where they show reactivity characteristics similar to one of the more important systems. Many of these systems of relatively minor significance are listed in Table 7.2. 

If chemical-specific information is not available, the consequences may be able to be predicted by methods using compatibility groups, or chemicals with similar chemical structures that are expected to have similar chemical reactivity characteristics. One computerized tool that uses this approach is the Chemical Reactivity Worksheet made available by the U.S. National Oceanic and Atmospheric Administration (NOAA 2002). This program has over 6000 chemicals, mixtures, and solutions included in its database. It also predicts chemical reaction consequences of combining two materials at a time (e.g., "Heat generation by chemical reaction, may cause pressurization"). Examples from the Chemical Reactivity Worksheet are shown in Section 4.2. It is critical that all chemicals be positively identified to have a complete evaluation of all potential incompatibilities. 

The configurational stability of chiral allenylmetal reagents depends to a large extent on the nature of the metal substituent. The mechanism of the racemization process has not been studied in detail, but two reasonable pathways can be proposed, based on known reactivity characteristics of these compounds. The first entails reversible intermolecular SE- rearrangement to the propargylic isomer. This process could proceed by a pure syn or anti pathway, in which case no racemization would take place. However, the occurrence of both pathways would result in racemization (Scheme 9.5). 

There is a paucity of experimental data regarding the transport and partitioning of disulfoton in air. Given the vapor pressure of 1.8x10 mm Hg at 20 °C (Melnikov 1971), disulfoton should exist almost entirely, in the vapor phase in the atmosphere (Eisenreich et al. 1981). Because of low particle diameter, the removal rate by dry deposition is low for compounds that exist in the vapor phase in the atmosphere (Schroeder et al. 1987) therefore, depending on its reactivity characteristics, vapor-phase disulfoton may travel long distances in the air. The solubility of 25 mg/L (Sanborn et al. 1977) ensures that at least partial removal of atmospheric disulfoton will occur by wet deposition. 

Extraction by supercritical fluids, in particular carbon dioxide and propane, is currently being investigated as a means of controlling the size and shape of particles for inhalation. Supercritical fluids are liquids above their critical pressure and temperature [28]. Under these conditions the molecules exhibit the flow, polarity, and solvency properties common of liquids but have the diffusivities and reactivities characteristic of gases. 

Abstraction of H2+ from 3-methylanisole, generated in a flowing afterglow triple quadrupole apparatus, gives the radical anion (18). This species undergoes electron transfer to F2 followed by attack of fluoride ion at the methoxy methyl group to give the distonic carbene ion Carbene (19) displays reactivity characteristic... 

Scheme 18) [72]. It is interesting to note that this MCR involving 5-aminotetrazole was unsuccessful and only the starting materials were reisolated from the reaction mixture. An explanation for this unreactivity could be the decrease in nucleophilicity comparing 3-amino-l,2,4-triazole and 2-aminobenzimidazole with 5-aminotetrazole. The same observations regarding the reactivity characteristics for these aminoazoles have already been reported before [73]. 

The fundamental structural and reactivity characteristics of carbocations, especially toward nucleophilic substitution, were introduced in Chapter 5 of Part A. 

The curing process of epoxies is mainly dependent on the reactivity characteristics, the structure, and the functional group of resin [61,65], The basic chemical reactions, catalyzed by hydroxyl group (OH), between the epoxide group and the curing agent are [194] ... 

A second major type of reactor involves thermal destruction of the calcium carbide. At about 1,S00°F, both calcium carbide and acetylene are thermally oxidized. Therefore, a system such as a rotary kiln could be used for thermal destruction of the reactivity characteristics. The additional benefit of thermal destruction is that it will also effectively deal with potential sulfide reactivity problems. Large chunks of metals often included in the desulfurization slag will tend to be a problem for many types of thermal units. Concern over air emissions and cost are other hurdles to the use of thermal systems for calcium carbide desulfurization slag. 

The fractional abundances of excited states in ion beams have been determined by making use of their different reactivity characteristics. Three methods have been employed, and these are described using 0+ ions as an example. 

It appears to the reviewer that the compensation effect has been incompletely exploited as a method of making quantitative comparisons of catalytic activity in different systems. The parameters B and e provide a more generalized measure of the reactivity characteristic of a series of related reactions (22)... 

It should be evident that radicals play a very important role within the realm of organofluorine chemistry. Fluorine substituents impart unique reactivity characteristics to free radical intermediates, and knowledge of how to generate and utilize such species is very important for those synthetic chemists who wish to incorporate fluorinated alkyl groups into organic substrates. It has been attempted in this review to provide a strategic overview of all aspects of organo-fluorine radical chemistry, with the hope that readers with an interest in the field will able to get their basic questions answered as well as be stimulated to dig deeper into specific aspects of the subject via the detailed references which have been provided. 

Significant efforts have been made to assemble teratogenic data basses with peer-reviewed evaluations (ref. 1). New avenues for the SAR studies have been opened, such as quantitative methods for structural superposition of molecules and for superposition of their reactivity characteristics (ref. 2). Emphasis has been placed on the electrostatic properties of the molecules, such as the molecular electrostatic potential, the electric fields, and the polarizability terms calculated from perturbation expansions (ref. 2). Computer-assisted multivariate SAR which deals with many variables simultaneously has been advanced (ref. 3). 

What are the characteristics of aromaticity What are the chemical reactivity characteristics of aromatic compounds ... 

As mentioned above, practical applications of the Klopman relationship (Equation 6.50) often require further simplifications, particularly in cases where the relevant MO properties are known only for one of the two reaction partners. The latter is the typical situation in QSAR investigations that aim to elucidate the impact of molecular reactivity characteristics on the toxic potential of chemical agents. While the Coulomb interaction term can be reduced to calculate net atomic charges (see above), a possible candidate to replace the orbital interaction term of Equation 6.50 by a one-molecule property is Fukui s delocalizability, as was pointed out over 35 years ago (Cammarata, 1968 Cammarata and Rogers, 1971). 

Predictive hazard evaluation procedures may be required when new and different processes, designs, equipment, or procedures are being contemplated. The Dow Fire and Explosion Index provides a direct method to estimate the risks in a chemical process based upon flammability and reactivity characteristics of the chemicals, general process hazards (as exothermic reactions, indoor storage of flammable liquids, etc.) and special hazards (as operation above the flash point, operation above the auto-ignition point, quantity of flammable liquid, etc.). Proper description of this index is best found in the 57-page Dows Fire and Explosion Index, Hazard Classification Guide, 5 th ed., AIChE, New York, 1981. 

The HSs and other aquatic and soil organic compounds interact with other components of the environmental system. Various kinds of clay organic intercalation compounds have been described, which are able to initiate unique photochemical reactivities characteristic of their specific molecular arrangements these differ considerably from solution photochemistry [18]. 

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