Packed column gas chromatography

The product may be analyzed by use of a gas chromatography column packed with either LAC-728 (diethylene glycol succinate) or Carbowax 20M suspended on Chromosorb P. Using a 2.5-m. LAC-728 column heated to 100°, the submitters found retention times of 9.4 and 13.0 minutes for cyclohexyl methyl ketone and cyclohexyldimethylcarbinol. Less than 1% of the carbinol by-product was present. 

The various fractions of the forerun were analyzed employing a gas chromatography column packed with silicone gum, No. XE-60, suspended on Chromosorb P and heated to 248°. The components found (with the retention times indicated) were benzyl bromide (9.0 minutes), 2-methylcyclohexanone (5.3 minutes), and, in some cases, bibenzyl (22.6 minutes). The bibenzyl, formed by reaction of the benzyl bromide with the excess methyllithium, was identified from the infrared spectrum of a sample collected from the gas chromatograph. 

The progress of this reaction may be followed by quenching aliquots of the reaction solution in acidic aqueous ammonium sulfate followed by extraction with ether and analysis of the ethereal extract by gas chromatography. With 1.2-m. gas chromatography column packed with silicone fluid. No. 710, on Chromosorb P and heated to 215°, the retention times of naphthalene and 1-bromonaphthalene were 1.9 minutes and 6.7 minutes, respectively. The submitters employed a 30-cm. gas chromatography column packed with Porpak P for this analysis. 

On a 2-m- gas chromatography column packed with 10% Apiezon L and heated to 100°, the retention times for N,N-dimethylcyclohexylamine and cyclohexanol are 15 and 4 minutes, respectively. The composition of this forerun is 80-85% of the amine and 20-15% of the alcohol. 

On a gas chromatography column, packed with Apiezon M suspended on Chromosorb P and heated to 70°, the product exhibits a single peak with a retention time of 23.2 minutes. The sample exhibits infrared absorption (CCI4 solution) at 3100, 3030, 2985, 1440, 1340, and 1235 cm. with n.m.r. singlets (CCI4 solution) at 3.45 (CHaBr) and 0.90 p.p.m. (cyclopropyl CHj). The mass spectrum of the sample has abundant fragment peaks at m/e 149, 147, 67, 41, and 39. 

The product was analyzed with a 2-m. gas chromatography column packed with Carbowax 20M suspended on... 

The product may be analyzed by using a gas chromatography column packed with 20% SF-96 suspended on Chromo-sorb WAW, 5 ft. by 0.25 in., operated at 140°. Using a helium flow rate of 60 ml. per minute the submitters found a retention time of 3.5 minutes. 

Benzene was passed at various temperatures through a gas chromatography column packed with silica gel and the following specific retention volumes (extrapolated to zero sample size) were measured ... 

A gas chromatography column packed with Apiezon L suspended on Chromosorb P was employed for this analysis. In a typical analysis at 140° the retention times were A1,9-octalin, 46.2 minutes A910-octalin, 49.2 minutes. The n.m.r. spectrum (CC14 solution at 60 mHz.) of this mixture exhibits a multiplet at S 0.8-2.6 (aliphatic CH) with a weak, partially resolved multiplet at <5 5.25 (vinyl CH of A1,9-octalin). 

The product exhibits a single peak (retention time 5.7 minutes) on a 4-m. gas chromatography column packed with silicone fluid QF on Chromosorb P and heated to 191°. This material has the following spectral characteristics i.r. (CCI4) 1675 (conjugated C==0) and 1623 cm. (conjugated C=C) ... 

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