Liquid-Solid and Capillary Gas-Liquid Chromatography of Internal Olefin Isomers.

Chapman, L. R.; Kuemmel, D. F.

doi:10.1021/ac60231a046

Cited by 33 publications

(17 citation statements)

References 5 publications

(4 reference statements)

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“…The diazoketones la [6] and 2a were prepared from the 2-norbornene-7-syn-and 7-anti-carboxylic acids (lb, 2b) of known configuration [7]: the 1:3 mixture of the methyl esters [7] was separated by chromatography [8] and hydrolysed. 2b was hydrogenated to 5b [9].…”

Section: Discussionmentioning

confidence: 99%

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π‐Participation in Diazoketone Hydrolysis II; Exo‐endo Cyclization Ratio in the Hydrolyses of 7‐syn‐ and 5‐endo‐Diazoacetyl‐2‐norbornene

Malherbe

Dahn

1977

Helvetica Chimica Acta

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SummaryThe rate of the acid-catalysed hydrolysis of 7-syn-diazoacetyl-2-norbornene (la) is enhanced relative to that of the saturated analogue 5a by a factor of 835. In contrast to the behaviour of other primary diazoketones, the substitution step is no longer rate-determining (mechanism A -2), but so much accelerated that the preceding proton transfer becomes the slow step (mechanism A-SE2, demonstrated by a solvent isotope effect kH/kD = 1.76). Product analysis shows 100% cyclization; the product formation is explained in terms of brexyl and brendyl type carbenium ions (or ion pairs). -5-endo-Diazoacetyl-2-norbornene (3a) shows very slight acceleration, and forms only 27% cyclization products (identical to those formed from la). Thus, in spite of the absence of steric hindrance by hydrogen atoms, the exo-endo rate ratio for anchimeric assistance is 3 lo3.Acid-catalysed hydrolysis of primary diazoketones follows the A -2 mechanism, rapid preequilibrium protonation forming a diazonium ion, followed by ratedetermining substitution [2] by a nucleophile. As the diazonium group is very sensitive, a weak nucleophile, for instance H 2 0 [3], is sufficient.H' , rapid R-CO-CHN, FR-CO-CHZNZ H20 ,R-CO-CH,OH+ N2+ H+ rate-det.A double bond in 5,6-position relative to the diazomethyl group can compete with a weak external nucleophile and form cyclic products [l] [4] [5]. The neighbouring group participation can furthermore result in a rate enhancement; we found this particularly with methylated cyclic olefins: 4-diazoacetyl-1,2-dimethylcyclopent-1-ene is hydrolysed about ten times more rapidly than diazoacetylcyclopentane [5]. We now present the results of a study of the hydrolyses of compounds in which the diazoacetyl group is kept in a rigid framework; 7-syndiazoacetyl-2-norbornene (la) and its anti isomer (2a), 5-endo-diazoacetyl-2-norbornene (3a) and its exo isomer (4a) have been compared with the saturated analogues 7-diazoacetyl-and 2-endo-diazoacetyl-norbornanes (5 a, 6 a).

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Section: Discussionmentioning

confidence: 99%

“…spectrum indicates syn: anti= 1:3. The mixture, (4.0 g) was separated on a column of SiO2 pretreated with AgN03 [8], eluted with ethedpetrol ether 1:2. Pure 2d (2.23 g) and pure Id (0.84 g) (GC.)…”

Section: Experimental Partmentioning

confidence: 99%

π‐Participation in Diazoketone Hydrolysis II; Exo‐endo Cyclization Ratio in the Hydrolyses of 7‐syn‐ and 5‐endo‐Diazoacetyl‐2‐norbornene

Malherbe

Dahn

1977

Helvetica Chimica Acta

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“…The gas chromatographic analyses were performed on 150 ft • 0.01 in. capillary column coated with polyphenyl ether, a method described by Chapman and Kuemmel (16). The composition was determined based on weights of fractions obtained by TLC.…”

Section: Discussionmentioning

confidence: 99%

The effect of process conditions on positional and geometric isomerization during partial hydrogenation of trilinolein with copper catalyst

Kirschner

Lowrey

1970

J Americ Oil Chem Soc

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The effects of some process conditions on isomer distributions during the partial hydrogenation of trilinolein with a copper type catalyst were studied. Modest effects on diene isomer distributions were noted by changes in temperature. Pressure and catalyst concentration, however, had little or no effect on diene isomer distributions over the range studied. Distribution of monoene isomers appeared to be insensitive to process conditions and extent of the reaction and suggests an equilibrium reaction. Very small amounts of saturates, if any, were formed during the reactions. The data support a conjugation then hydrogenation mechanism for hydrogenation of glyceryl dienoates with copper catalysts.

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“…stream at 180-200°C for 8 hr following distillation. The isomerized olefins were analyzed according to the method given in the literature (4). The trans/cis ratio was 2.7 and the distribution of the double bond position was as follows: 1-{2.2%}, 2-(16.9%), 3-(17.0%}, 4-plus 5-{34.5%} and 6-plus 7-{27.9%).…”

Section: Methodsmentioning

confidence: 99%

NMR study on sulfonation of internal olefins

Yoshimura

Endo

Hashimoto

1991

J Americ Oil Chem Soc

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Terminal olefins can be converted into the corresponding sulfonates by sulfonation with SO3 followed by hydrolysis, the products are used as detergent ingredients. Although internal olefins were also expected to be good feed stocks, it was difficult to convert them into the corresponding sulfonates with as good of a yield as that of terminal olefins under the same synthesis conditions. Our studies have been carried out in order to clarify the reason for poorer conversion of the internal olefins. It was found by a nuclear magnetic resonance spectroscopic study that the major components of the sulfonated intermediate of internal olefins were /~-sultones, the amounts of which were usually very small in sulfonated terminal olefins. A portion of these/3-sultones was desulfonated, depending on temperature, to the original olefins and the corresponding sulfate salts during alkaline hydrolysis. The prevention of desulfonation of the ~sultones in the hydrolysis process was one of the most important aspects for the production of internal olefin sulfonates.Finally, by keeping the hydrolysis temperature below 35°C, the conversion of internal olefins into sulfonates was achieved with the same yield as that of conventional terminal olefins.KEY WORDS: a~Olefin, a~olefin sulfonate, alkenesulfonate, AOS, f~ sultone, carbyl sulfate, desulfonation, y-sultone, hydroxyalkanesulfonate, internal olefin sulfonate.

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Liquid-Solid and Capillary Gas-Liquid Chromatography of Internal Olefin Isomers.

Abstract: The addition of graphite powder to the fused sample was necessary to improve sparking characteristics. Europium oxide was chosen as an internal standard chiefly because it was not likely to be encountered in samples.

Cited by 33 publications

References 5 publications

π‐Participation in Diazoketone Hydrolysis II; Exo‐endo Cyclization Ratio in the Hydrolyses of 7‐syn‐ and 5‐endo‐Diazoacetyl‐2‐norbornene

π‐Participation in Diazoketone Hydrolysis II; Exo‐endo Cyclization Ratio in the Hydrolyses of 7‐syn‐ and 5‐endo‐Diazoacetyl‐2‐norbornene

The effect of process conditions on positional and geometric isomerization during partial hydrogenation of trilinolein with copper catalyst

NMR study on sulfonation of internal olefins

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