P-ethylaniline

Fig. 5.5. GC separation of TFA derivatives of arylamines. Peak 1 = solvent (CH2CI2) 2 = N-methyl-aniline 3 = N,N-dimethylaniline 4 = N-ethylaniline 5 = N-methyl-o-toluidine 6 = N-methyl-m-toluidine 7 = N-methyl-p-toluidine 8 = o-toluidine 9 = o-ethylaniline 10 = aniline 11 = 2,5-dimethyl-aniline 12 = 2,6-dimethylaniline 13 = 2,4-dimethylaniline 14 = m- toluidine 15 = p-toluidine 16 = 2,3-dimethylamline 17 = 3,5-dimethylaniline 18 = m-ethylaniline 19 = p-ethylaniline 20 = 3,4-dimethylaniline. Conditions stainless-steel column, 18 ft. X 0.125 in. O.D., 9.5% Apiezon L + 3.6% Carbowax 20M on Aeropack 30 (80—100 mesh) helium flow-rate, 100 ml/min column temperature, 152°C. (Reproduced from Anal. Chem., 39 (1967) 1188, by courtesy of the American Chemical Society.)...

In recent years, several tests have been developed to characterize the silanophilic properties of RP phases. These tests are usually based on the behavior of the phases towards basic substances, as, for example, in the case of the EngeUiardt test, whereby acidic, neutral, and basic compounds are used. As a measure of the silanophilicity, one uses either the elution of a base compared to phenol (an earlier elution than phenol indicates a low silanophilicity of the phase) or the asymmetry factor of p-ethylaniline in a methanol/water eluent Recent results show that a classification by these criteria can only be quite rough silanophilic / hydro-phobic . 

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