4-methyl- 346 COMPOUND INDEX

Aluminium triethyl may he prepared in a similar manner to the methyl compound. Aluminium triethyi is a liquid, B.pt. 194° C. when distilled in hydrogen it does not solidify at —18° C. It is decomposed with explosive violence by water with iodine it yields ethyl iodide and iodine derivatives. At 234° C. the vapour density is 4 5 (theory 8 9), the refractive index ha ing the value hb 1-480 at 6-5° C. 

As follows from Table I (see Section VII Index of Tables), the yields in 4-acetylenyl compounds depend both on the reaction time and on the structure of the aromatic and acyclic components (molecular polarity). If more than one equivalent of diazomethane is used, N-methylation of pyrazole occurs. 

With more than 30 million organic compounds now known and thousands more being created daily, naming them all is a real problem. Part of the problem is due to the sheer complexity of organic structures, but part is also due to the fact that chemical names have more than one purpose. For Chemical Abstracts Service (CAS), which catalogs and indexes the worldwide chemical literature, each compound must have only one correct name. It would be chaos if half the entries for CH3B1 were indexed under "M" for methyl bromide and half under "B" for bromomethane. Furthermore, a CAS name must be strictly systematic so that it can be assigned and interpreted by computers common names are not allowed. 

Detectability may be a significant problem with homologous series of unsaturated compounds, particularly //-alkanes. For these compounds, refractive index detection or evaporative light-scattering, both of which are described elsewhere in the book, may be of use. Indirect photometry is a useful detection scheme for compounds that do not absorb in the UV. Acetone, methylethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, and acetophenone are added to an acetonitrile/water mobile phase, generating a negative vacancy peak when the nonchro-mophoric analyte emerges and a positive peak if the ketone is adsorbed and displaced.70 Dodecyl, tetradecyl, cetyl, and stearyl alcohols also have been derivatized with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole and the derivatives separated on Zorbax ODS in a mobile phase of methanol and 2-propanol.71... 

Methyl- and 3-ethylsydnone have been used as aprotic solvents for electrolytes <2000MI20, 2002MI334>, whereas 3-phenylsydnone has been employed as a filter for recording the absorption spectra and refractive indexes of polymer films containing other mesoionic compounds <2002MI2290>. 

A number of researchers have also used a proposed ASTM test mixture, benzaldehyde, acetophenone, methyl benzoate, dimethyl terphtha-late, benzyl alcohol, and benzene to demonstrate separation on a column [98]. However the first four compounds are from the same interaction group and should behave in the same way on changing conditions. The first three have almost constant indices (respectively 760, 800, and 890) so that in effect they create an index scale with constant differences against which the last two compounds can be compared [96,99]. 

Individually indexed compounds are f Butanethiol, 1712 f 2-Butanethiol, 1713 Dodecanethiol, 3567 f Ethanethiol, 0933 f Methanethiol, 0489 f 2-Methylbutane-2-thiol, 2023 f 3-Methylbutanethiol, 2024 f 2-Methylpropanethiol, 1715 f 2-Methyl-2-propanethiol, 1716... 

Many alkyl nitrites are thermally unstable and may readily decompose or explode on heating [1], Methyl nitrite explodes more violently than ethyl nitrite [2], Lower alkyl nitrites have been known to decompose and burst the container, even in refrigerated storage [3], Individually indexed compounds are f Butyl nitrite, 1658 f fert-Butyl nitrite, 1659... 

An index is included at the end of the book which lists potential sources or origins for the contaminant of concern of interest. The index also includes compounds for which degradation products are known, e.g., the presence of 1,1-dichloroethane at a site may be indicative of a release containing 1,1,1-trichloroethane (where 1,1-dichloroethane is present as an impnrity) or it may be a degradation product of 1,1,1-trichloroethane. Therefore, under the 1,1-dichloroethane entry, the reader is directed to the chemical profile 1,1,1-trichloroethane. Moreover, the index inclndes compounds which occur as additives to various products, e.g., acrolein nsually contains hydroqninone to prevent polymerization. Many commercial prodncts released into the enviromnent may contain other compounds present as impurities, e.g., 1,4-dioxane may contain the impurities acetic acid, 2-methyl-1,3-dioxolane, and bis(2-chloroethyl) ether. 

A further aid in the location of the solvents and their exact specification is the Chemical Abstracts (CAS) Registry Number, shown in the second column. The Chemical Abstracts name may be the same as the commonly used one or may differ from it considerably, so that it is not always easy to find the solvents in these Chemical Substance Indexes of the Chemical Abstracts. Eor instance, benzene, methyl is a fairly transparent name for toluene, and methanol, phenyl a slightly less one for benzyl alcohol, but one has to become familiar with the systematics of Chemical Abstracts nomenclature in order to search for diethyl ether or any other more complicated compound. It is expected that with all this information available in table Al the solvents listed are definitely specified and readily found in the Abstracts and other compilation of information and data. 

The formulas for compounds described in volume 34 are entered in alphabetical order. They represent the total composition of the compounds, e.g., BF24KC38H21 for potassium tetra-3,5-bis(trifluoro-methyl)phenylborate. The elements in the formulas are arranged in alphabetical order, with carbon and hydrogen listed last. All formulas are permuted on the symbols other than carbon and hydrogen representing organic groups in coordination compounds. Thus potassium tetra-3,5-bis(trifluoro-methyl)phenylborate can be found under B, F, and K in this index. 

BMIs and maleimide-terminated prepolymers have been considered for systems with improved Fire, Smoke and Toxicity properties. Of particular interest are phosphorous-containing bismaleimides because they provide high Limiting Oxigen Index (LOI) values (30). 3,3 -bis(maleimidophenyl) methyl phosphine oxide is such a compound (Fig. 7). 

Its Acetone Compound ceMed 3,3,6,6,9,9-Hexa-methyl-1,2,4,5-tetroxonane in CA 5th Decennial Formula Index),(CH3)2C-CH2.CH2------C(CH3)2 ... 

Figured.1.4 An FID chromatogram of concentrated extract of the same Concord grape essence shown Figure G1.1.3, drawn to display the data on a linear retention index scale. By simply comparing the index of a peak with the data listed in the flavornet, the odorants that have similar retention indices can be determined. Notice how large the methyl anthranilate peak is, but still no convincing peak for p-damascenone, even though both compounds have the same odor activity (intensity).

NMR mass chromatogram corresponds to a one-dimensional UV or refractive index chromatogram. The second peak consists of methyl methacrylate and ethyl acrylate, which is evident from the different chemical shifts provided from the on-line experiment. A clear differentiation is available from the chemical shift of the methyl group of both compounds. The chemical shift at 1.9 ppm indicates the methyl group at the double bond of methyl methacrylate, whereas the signal at 1.22 ppm is from the terminal methyl group of ethyl acrylate. Thus, the second dimension of the SFC-NMR run, provided by the H chemical shifts, enables the separation of co-eluting compounds. 

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