INDEX methyl derivatives

CAS 68609-96-1 EINECS/ELINCS 271-845-2 Synonyms Alkyl (C8, CIO) glycidyl ether C8-10 glycidyl ether Octyidecyl glycidyl ether Oxirane, mono ((C8-10-alkyloxy) methyl derivs. Classification Nonaromatic ether Definition Glycidyl ether of C8-10 alcohols Properties Dens. 0.900 ref. index 1.4420 Toxicology Irritant sensitizer possible mutagen TSCA listed Uses Reactive epoxy diluent functional monomer modifier for coatings. 

Number of compound Name Abbrev. Retention index of methyl derivative Retention index of trimethylsilyl derivative ... 

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... 

Fig. 18 RP-HPLC of methylesters derived from three different fish oil sources sardine (A), menhaden (B), and cod liver (C). Identified fatty acid methyl esters in order of their elution 1. C20 5o 3 2. C14 0 3. C16 lw9 4. C22 6o>3 5. C18 2a>6 6. C16 0 7. C18 1 >9. BHT is eluted right after the void volume remaining peaks have not been positively identified. Mobile phase acetonitrile/THF/water (9 5 11) at 2.0 ml/min stationary phase WHATMAN ODS-3 RAC II (100 X 4.6-mm ID) detection, refractive index at ambient temperature.

The Battelle group found that photoisomerization of various indigo derivatives could be used to record holograms which had low (<0.2%) scattering efficiencies (36). Their refractive-index data yield nQ = 2.9 x 10 cm for an N,N -dibenzoylindigo derivative. These systems were reversible. The quantum yields of isomerization were much lower in poly(methyl methacrylate) or polystyrene than in fluid solution, in accord with arguments presented earlier. Concentration quenching was also observed in solution. 

In this system, amphetamine, 3,4-methylenedioxyamphetamine (MDA) and the A-methyl and A-ethyl analogues of the drugs were derivatized, with 4-chloroamphetamine being used as the internal standard. For powders, solutions were prepared at concentrations of 1 mgml in methanol and a 100 til aliquot blown dry under nitrogen. To the residue was added 50 p.1 of 0.5 M KOH and 500 p,l of toluene. The mixture was then shaken for 30 s and centrifuged, after which the toluene layer was recovered and HFBA (5 til) added. The excess reagent was neutralized with 500 p,l of 10% NaHCOs and an aliquot (1 ttl) analysed by GC-MS. Each of the amphetamines and the A-alkylated derivatives could be separated and identified on the basis of retention index and mass spectral data. 

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. 

The same types of A-acyl-O-alkyl derivatives can also be used for GC analysis of the simplest oligopeptides (at least dipeptides and tripeptides). Other, obsolete, recommendations on the GC analysis of these compounds include various sequences for their reduction by LiAlH4 into polyaminoalcohols, followed by N-acylation or per-methylation and, finally, silylation of OH groups. For example, A-TFA dipeptide Phe-Phe after reduction and silylation gives the compound (III) with a retention index of 2390 on semistandard-phase Dexsil-300. 

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