Available for addition

This forms individual hydrogen atoms adsorbed to the surface of the metal. These hydrogen atoms are now available for addition across the alkene. The addition reaction begins when the alkene coordinates with the metal surface ... 

Remember from Chapter 6 that energy is released when a bond forms. Consequently, atoms that form covalent bonds tend to use all their valence s and p orbitals to make as many bonds as possible. We might expect the S p -hybridized aluminum atom to form a fourth bond with its unused 3 p orbital. A fourth bond does not form in A1 (C2 115)3 because the carbon atoms bonded to aluminum have neither orbitals nor electrons available for additional bond formation. The potential to form a fourth bond makes triethylaluminum a very reactive molecule. 

Chuck seemed almost like a humanoid computer without enough batchprocessing tasks in his queue and available for additional programming. It was not difficult to interest Chuck in our volunteer testing program. 

The interconversion of aldoses and the respective 2-ketoses in alkaline solution may be somewhat more complex than originally supposed, as it has been reported that a partial transfer of hydrogen from C-2 of the aldose to C-l of the corresponding ketose occurs during the reaction.29 This observation is not inconsistent with isomerizations that involve 1,2-enediol intermediates. The transfer could occur as a result of a rapid conversion in which some of the protons originally at C-2 of the aldose molecules are retained by the solvent cage that surrounds the intermediate 1,2-enediol, and are, therefore, available for addition to C-l of the resulting ketose. It should be noted that other interpretations, such as hydride-transfer mechanisms, are also possible. 

The allenic ether (204) cyclizes to spiro compounds in the presence of potassium r-butoxide and dicyclohexano-18-crown-6. Acid hydrolysis yields the dihydrofuranone (205). The new carbonyl compound l-oxaspiro[4,4]nonan-4-one can be subjected to another spiroannela-tion sequence. The carbonyl group in (206) has two faces available for addition of a nucleophilic species. Only one product is formed, a cyclopentyl[3]helixane (207). One can in principle continue this reiterative reaction (Scheme 53) (B-81MI31200). 

Data is also available for addition reactions of electrophilic radicals, CH(CN)2, and so-called ambiphilic radicals, CH(C02Et)2 and CH2C02-/-Bu, which derive their electrophilic character from n-delocalization of the carbon-centered radical onto electron-attracting substituents [108-111], and for which the enthalpy of the addition process rather than the polar nature of the radicals may be the primary rate-determining factor [112,113]. 

There is little rate data available for addition and abstraction reactions involving higher alpha-olefins. Where such data are available, they have usually been obtained from lower temperature studies (12,13,14), However, the available information indicates that addition should be competitive with abstraction in the temperature range of this study. For example, Steacie s data for ethyl radical reactions with 1-hexene and 1-heptene indicate that at 525°C, the addition rate would be about seven-tenths of the abstraction rate. For dodecene, one would expect this ratio to decrease because of the increase in abstractable hydrogen, but addition should still be a significant pathway. For methyl radicals and H atoms, available data (13,14) indicate that addition is somewhat faster relative to abstraction. 

A more ingenious route involves the dehydrobromination of ester 1 in a benzene solution containing a catalytic amount of ethanol and using sodium hydride as base. The ethoxide ion, being a stronger base in benzene than in ethanol, deprotonates the substrate and is converted to ethanol. As a result much less ethoxide is available for addition to the triple bond, thus affording the ethyl phenylpropiolate and the ethyl P-ethoxycinnamate in ca. 56% and 27% yield, respectively . 

For broader bandpass filters, neodymium glass filters are available for additional wavelength calibration in the visible region. Special NIST reference materials referred to as SRM (standard reference materials) numbers are available for calibration and verification from the National Institute of Standards and Technology. Information about these standards can be accessed directly from the Internet (http //www.i-nist. gov/itl/ div898 / index.html). 

Jimenez-Gonzalez, 2000, 2003a). This methodology is transparent, well documented, and extremely flexible. Modular Gate-to-Gate (GTG) LCIs for materials can be used to construct chemical trees from an advanced material back to the cradle, and the inventories rolled-up to obtain a Cradle-to-Gate (CTG) LCI. Its utility was demonstrated for a typical, commercially successful GSK API (Curzons et al., 2001). These GTG LCI data were also available for additional analysis that led to the development of the FLA SC tool (Curzons et al., 1999). 

A further advantage of this modern technique is the non-destructive nature of the IR-detection. This makes the out-flow available for additional detection techniques such as FID or MSD, or fraction collection of interesting substances [25-27],... 

This section provides a brief overview of the PAH remediation technologies available. For additional information on each process mentioned in this section, readers are encouraged to refer to other encyclopedia entries as well as established texts. ° ... 

At present there is considerable interest in studying various topics relating to or deriving from solid-state polymerization. This has come about because of interesting and potentially useful properties of several polymers formed by lattice-controlled processes and because of the natural desire to increase the number of systems available for additional study. The experimental results alluded to have been achieved in the last several years, and it is now appropriate to take stock of these activities to understand how and why they have come to their present state and also to see how they might be given greater breadth and depth. 

A short time after the demise of this initial network a similar one was begun by the U.S. Public Health Service (PHS) in 1960. This network was maintained until 1966 with management responsibilities eventually falling upon the National Center for Atmospheric Research (NCAR) ( ). No national network was operated after the closing of the PHS/NCAR stations in the 1960 s although several isolated measurement programs were carried out in various parts of the country An excellent summary of sampling activities in North America is available for additional information (13). 

It is a measure of the availability for additional electron density on the ath atom. 

Bp2pyr, in which each pyrazolyl ring is functionalized with a pyrazin-2-yl group at the C2 position, is a potentially chelating tetradentate ligand with two externally directed N atoms available for additional... 

Addition of an organomagnesium to a compound containing a carbon—carbon multiple bond provides a method of forming a new carbon—carbon bond and producing a new organomagnesium available for additional reactions ... 

After a vesicle and its target membrane have fused, the SNARE complexes must dissociate to make the individual SNARE proteins available for additional fusion events. Be-... 

Only two types of positions are available for addition to p-xylene. The adducts are represented in Fig. le) and f). In each of these positions, different interactions are possible the ones characteristic of addition at C, for the 1-OH adduct, and the one... 

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