Ucon LB Research Articles

Comparison of methods for prediction of the retention data of aromatic hydrocarbons on UCON LB 550X and on polydimethylsiloxane

A detailed statistical analysis is presented for comparing the validity of selected literature-recommended equations with the unified retention index concept for calculating the retention indexes of alkylbenzenes on UCON LB 550X and naphthalenes on polydimethylsiloxane. Comparison with literature sources shows that the unified retention index provides the smallest residual error for a set of aromatic hydrocarbons.

Structure-retention correlations of hydrocarbons in GLC and GSC alkenylbenzenes

For the study of relationships between retention behaviour and molecular structure in GLC and GSC the retention indices of alkenylbenzenes with 2–6 carbon atoms in a straight or branched side chain and of isotopological alkylbenzenes were determined on capillary columns coated with OV-1 and Ucon LB and on a micropacked column filled with graphitized thermal carbon black. From the values obtained index differences corresponding to the increments of the double bond in the side chain were derived. These differences depend significantly on the structure of the side chain and of the position of the double bond.

Structure-retention correlations of hydrocarbons in gas-liquid and gas-solid chromatography. Cycloalkenes and cycloalkadienes

The retention indices of cycloalkenes and cycloalkadienes with C6–C13 rings are determined by gas-liquid chromatography (GLC) on glass capillary columns coated with OV-1 and Ucon LB 550X and by gas-solid chromatography (GSC) on a microcolumn packed with uncoated graphitized thermal carbon black (GTCB). Structure — retention correlations are derived on using index differences such as HOV, HGTCB and ΔI values, considering the differences in the stereochemistry of these compounds. It is shown that the combined application of index increments obtained in GLC and GSC provides more detailed structure informations. The value of the retention index units agree with the most stable conformations of the alicyclic compounds. The high value for the energy equivalent to an index unit (ΔGI.U.=4.18kJ/mol) confirmes that graphitized thermal carbon black causes much stronger dispersive interactions than any nonpolar liquid phase.

Molekülstruktur und retentionsverhalten : XII. Zur retention von alkylnaphthalinen bei der gasverteilungs- und gas-adsorptions-chromatographie

Molecular structure and retention behaviour. XII. Refention behaviour of alkylnaphthalenes by gas-liquid and by gas-solid chromatography The retention indices of 1-alkyl- and 2-alkylnaphthalenes, of isomeric dimethylnaphthalenes, of some trimethylnaphthalenes and methylazulenes have been determined by gas—liquid chromatography (GLC) on glass capillaries of different polarity (methylsilicone OV-1, Ucon LB 550 X and Ucon 50 HB 280 X polar) and by gas—solid chromatography (GSC) on graphitized thermal carbon black, respectively. The retention within homologous series of straight chain 1-alkyl- and 2-alkylnaphthalenes, of isomeric butylnaphthalenes and dimethylnaphthalenes is discussed by means of homomorphic factors and index differences and compared with corresponding values of alkylbenzenes. The different retention behaviour of the isomeric dimethylnaphthalenes by GLC and by GSC can be described by an incremental approach.

Molekülstruktur und retentionsverhalten : VIII. Zum gaschromatographischen retentionsverhalten von dicyclopentadienderivaten

Molecular structure and retention behaviour. VIII. Gas chromatographic retention behaviour of dicyclopentadiene derivatives The retention indices of exo—endo isomeric dicyclopentadienes, dihydrodicyclopentadienes and tetrahydrodicyclopentadienes have been determined by gas—liquid chromatography (GLC) on glass capillaries coated with squalane, Ucon LB 550X and Ucon 50HB 280 X polar, and by gas—solid chromatography on graphitized thermal carbon black. The influence of exo- and endo-configuration of the carbon skeleton and of the position of the double bond on retention is discussed by means of homomorphic factors and index differences. In the same manner the relationships between retention and configuration of the carbon skeleton and of the substituent are elucidated from the retention indices of 9-hydroxy-, 9-acetoxy-, 9-ketodihydrocyclopentadienes and substituted tetrahydrodicyclopentadienes, respectively, obtained by GLC on capillary columns with different polarity.

Gas chromatography separation of naphthalene and biphenyl homologues on capillary columns

Experimental conditions were investigated that would permit an optimal separation of methyl-, ethyl- and dimethylnaphthalenes, biphenyl, diphenylmethane, methylbiphenyls and acenaphthene to be obtained. Retention times were determined on efficient capillary columns prepared with the following stationary phases: SP 400 Reoplex 400, Amine 220, p 2 P′-azoxyphenetole, Bentone 34 mixed with didecyl phthalate and UconLB 550 X mixed with tris(cyanoethoxy)propane, and on a composite capillary column consisting of the last two columns, i. e, Bentone 34 and didecyl phthalate plus Ucon LB 550 X and tris(cyanoethoxy)propane. The complete separation of all the naphthalenes was obtained only on thbe last-mentioned composite column.

Manufacture of glass open-tubular columns by dehydration of the surface

Methods are described for the preparation and coating of glass open-tubular columns. By dehydration of the inner surface during the drawing operation, an oxide-type glass surface can be obtained which is completely wettable by non-polar and most polar liquid phases without further treatment. For coating the columns, a modified dynamic method was used. Squalane and OV-101 were used as non-polar phases and Ucon LB, Carbowax 20M and OV-17 as polar phases. Our procedure resulted in open-tubular columns of high efficiency, having a thin uniform film (0.03–0.1 μm) and possessing 3000–10 000 theoretical plates per metre. In order to decrease the phase ratio, small-diameter columns (0.1–0.15 mm) were used. Several of these columns have been in routine daily use for nearly 1 year without any decline in efficiency.

Chlorophosphonation of 1-Choropropane and 1-Chlorobutane

Chlorophosphonation of 1-chloropropane and 1-chlorobutane was carried under condition of the reactant ratio of 1 : 5 of the chloride to PCl3, with oxygen gas flow rate of 200 ml/min at-150°C, for 3 hrs.The reaction products were analyzed by GLC using a 3 m ×3 mm φ column, packed with Ucon LB 550 X, with nitrogen gas carrier.In the case reaction of 1-chloropropane, the products obtained were as follows, 1-chloro-1- (13.7%), 1-chloro-2- (43.6%), 1-chloro-3-dichlorophosphinylpropane (32.7%), and 1-chloro-2-dichlorophosphinyloxypropane (10.0%).In the case reaction of 1-chlorobutane, the products obtained were as follows 1-chloro-1- (7.9%), 1-chloro-2- (17.0%), 1-chloro-3- (38.6%), 1-chloro-4- (23.1%), 3-chloro-1-dichlorophosphi-nylbutane (3.1%), and 1-chloro-2-dichlorophosphinyloxybutane (10.3%).The mechanisms of the formations of dichiorophosphinyloxyalkane and the chlorine-migrated isomers were discussed.

Chlorophosphonation of Methyl Carboxylates

Chlorophosphonations of some methyl carboxylates were carried out under the condition ; 1 : 5 of the mole ratio of methyl carboxylate to PCl3, 200 ml/min of the flow rate of oxygen, -15-0°C and 3 hrs. The products were esterified with ethanol, and the diethyl esters were used for G.L.C. analysis, using a 3 m × 3 mmφ, Ucon LB 550 X column. The G.L.C. peaks of the products were identified by the comparision of their retention times with those of the peaks of authentic samples synthesized by other methods independently. Isomer distributions were calculated from the area ratios of the G.L.C. peaks. The relative reactivities of C-H bonds of the methylene group to the C-H bond of the terminal methyl group as reference standard, are shown in the following Table.

Chlorophosphonation of Methyl Alkyl Ether

Chlorophosphonations of methyl n-alkyl ethers with the alkyl chain of C3-C6 were carried out in the condition of the reactant ratio of 1 : 5 of the ether to PCl3, with oxygen gas flow rate of 100ml/min, and at -15-0°C, for 3 hrs.The distributions of the product isomers were determined by GLC using Ucon LB 550X column, 3m×3mmφ with nitrogen gas carrier.The relative reactivities of the C-H bond of the ether to the terminal methyl of the alkyl group (R) are shown in the following Table.1-Methoxy-1-dichlorophosphinylalkane could'nt be obtained.

Chlorophosphonation of Acid Chloride

Chlorophosphonation of some acid chlorides was carried out under the condition of the mole ratio of acid chloride to PCl3 1 : 5, the flow rate of oxygen 200ml/min, the temperature -2010°C, and the reaction time for 3hrs. The compositions of the products, esterified with ethanol, were identified by GLC (Ucon LB 550 X, 203226°C, N2 gas carrier) in comparision with authentic samples synthesized by other methods. The product distribution (mol%) in chlorophosphonation of acid chlorides is as follows.

Chlorophosphonation of α-Olefins

Chlorophosphonation of α-olefins was carried out. The product mixtures were esterified with ethanol and analyzed by GLC, using 3m×3mm φ, Ucon LB 550 X column, and identified by the comparison to authentic samples synthesized by other methods.In paralell to the substitution of dichlorophosphinyl group in methylene C-H, an addition of chlorine and dichlorophosphinyl group to the double bond of α-olefin occurred. Substitution at the allylic methylene group scarcely occurred in comparison with the substituton in other methylene groups.Chlorophosphonation of saturated hydrocarbon was inhibited completely by addition of a small amount of sulfur or iodine. However the reaction of α-olefin or the mixture of α-olefin with saturated hydrocarbon did'nt be inhibited in the similar manner and the chlorophosphonated products were obtained in tolerable yields. This might be attributed to the intermediate formation of allylic hydroperoxide, which plays a role in the initiation of the radical reactions.

Chlorophosphonation of n-Alkyl Acetate

Chlorophosphonations of n-alkyl acetates (CH3COOR; R=C3C8) were carried out and the products were analyzed with GLC, using 3m×3mmφ, Ucon LB 550X column, and identified by comparing their retention times with those of authentic samples synthesized by other methods. The compositions of the products were determined. The results were expressed with relative reactivities per hydrogen at methylene groups to the terminal methyl group as standard, as shown in Table. The substitution of dichlorophosphinyl group on the acetyl group did'nt occur.

Gaschromatographische trennung stellungsisomerer aliphatischer sulfonsäuren und sulfocarbonsäuren in form ihrer methylester

The quantitative estimation, by gas chromatography, of the theoretically possible sulphonic acid stereoisomers of some paraffin hydrocarbons (via their methyl esters) and some sulphocarboxylic acids (via their dimethyl esters) is described. The analysis is carried out on packed columns ((filling: Resoflex or Silicone oil 550 on firebrick) and on capillary columns filled with Ucon LB 500 X or Apiezon M as the stationary phase. The gas chromatogram from the first column gives direct results, whereas correction factors obtained by running a test mixture of known composition must be applied to results obtained from the capillary column.

Techniques for Studying the Mechanism of Higher Alcohol Formation by Yeasts

Procedures developed for research investigations of the mechanisms of formation of higher aliphatic alcohols or fusel oil components during alcoholic fermentation are described. Fermentations of 20 per cent glucose solutions by resting cells of mutant strains of <i>Saccharomyces cerevisiae</i>, lacking the normal ability to synthesize one or more particular amino acids, were used. The higher alcohol fraction was quantitatively concentrated by one or two procedures, fractional distillation coupled with ether extraction or close fractional distillation alone. The fraction was analyzed by gas chromatography on a 6 ft x ¼ in. column containing Ucon LB 385 as the stationary active phase operated with helium carrier gas at 100°C. The separation of active and isoamyl alcohols required a second column with glycerol packing and used at 75°C. The individual alcohols produced in fermentations of radioactive carbon-14 intermediates were separated by gas chromatography. Sufficient amount (about 0.5 mg) were obtained by condensation of the effluents from a peak from a single injection onto the column to permit radioactive counting by liquid scintillation. The procedures are illustrated by reporting the results of an experiment in which glucose was fermented by a valine-, isoleucine-dependent mutant in the presence of α-aminobutyric acids, 1-C-14 and 2-C-14, as a source of α-ketobutyric acid. Of the higher alcohols the mutant produces only n-propanol and n-butanol. Both were labeled by the 2-C-14 acid, but neither by the 1-C-14 acid, since the carbon in the number one position is lost by decarboxylation when the α-keto acid is utilized by yeast to form an alcohol according to the Ehrlich scheme.