Chemical multiple

Conversion of a compound to a larger chemical multiple of itself... 

Chemical Multiplicity Number of Assignment Shift (ppm) Protons... 

Table 11 presents chemical multiplicity studies for which criterion 1 (stereospecific addition) was almost exclusively used to demonstrate the spin state of the cycloalkenecarbenes. 

Mutually unambiguous correspondence between initial analytes and derivatives must be assured. The optimal case is 1 —> 1, but some examples of type 1 2 are known (e.g., when the derivatives of enantiomers form a pair of diastereomers, O-atkyl ethers of oximes exist in syn and anti isomers, etc.). All processes that lead to further uncertainty (chemical multiplication of analytical signals) [e.g., 1 A (A > 3) must be excluded]. 

As discussed earlier, when the human body is exposed to toxic chemicals, multiple responses are induced. These responses are summarized in Table 4.9. 

Allergic to everything Allergic toxemia Autointoxication Candida hypersensitivity syndrome Cerebral allergy Chemical acquired immunodeficiency syndrome Chemical hypersensitivity disease Chemical multiple sensitivity Chemical-induced immune dysregulation Ecological illness Environmental illness or disease Environmental somatization disorder... 

The membrane-coated fiber technique has overcome these experimental difficulties. A membrane material coated onto a fiber is used as the absorption membrane to determine the membrane/solvent partition coefficients of chemicals. Multiple membrane/solvent systems can be calibrated with the probe compounds with known solute descriptors as follows. The partition coeffidrait of each probe compound in a given membrane/solvent system log is detmmined experimentally by the membrane-coated fiber technique. The log value of each probe compound is scaled to the solute descriptors of the compound with the LEER equation (Equation 5.1, where log SP = log K ). A LEER equation matrix is generated from all of the probe compounds (Equation 5.2). The system coefficients of each membrane/solvent system can be obtained by multiple linear regression analysis of the LEER equation matrix. 

Substitution reactions of resolved metal complexes can occur with retention or with inversion. Commonly, some activity is lost because of racemization. Since the late 1960s there have been developments in metal complexes containing chiral ligands which react catalytically in hi y enantioselective organic reactions. Small amounts of the chiral complexes can produce much larger amounts of products of high enantiomeric purity. This is referred to as chemical multiplication of chirality. 

The major problem still facing the viable recycle of plastic wastes is their chemical multiplicity several different pol5rmers are present in plastic wastes and many of them are mutually incompatible, making the reprocessing of them, as a whole, practically impossible. On the other hand, the separation of the individual plastics is extremely expensive and must consequently be simplified as much as possible. Therefore, many separation methods currently used, such as for instance flotation, cannot provide the individual components but only fractions which may contain several different polymers. Such heterogeneous mixtures are often scarcely compatible, giving rise to processability and quality problems. 

Noyori R. Centenary lecture. Chemical multiplication of chirality science and applications. Chem. Soc. Rev. 1989 18 187-208. 

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