Notes

Vahrman, M.; Lloyd, Douglas R.; McDougall, Ronald H.; Cady, G. H.; Emeléus, H. J.; Tittle, B.; Brown, Ivor John Carnegie; Martin-Smith, M.

doi:10.1039/jr9600004135

Cited by 4 publications

(2 citation statements)

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“…Higher reaction temperatures are known to increase acyl migration (Martin, 1953). When boric acid hydrolysis (Hartman, 1959) of 1,2-isopropylidene-3-behenoyl-ín-glycerol was attempted, the hydrolysis did not proceed, and the starting material was quantitatively recovered. However, the long-chain 1,2-isopropylidene-3-acyl-jn-glycerols (I, = 16,18, 20, and 22) were successfully hydrolyzed by applying the compounds to silicic acid and exposing them to hydrogen chloride gas at -75 °C for about 5-10 min.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and polymorphism of 3-acyl-sn-glycerols

et al. 1985

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3-Acyl-sn-glycerols with even-numbered saturated fatty acyl chains from decanoate to lignocerate were synthesized. Successful hydrolysis of the long acyl chain intermediate 1,2-isopropylidene-3-acyl-sn-glycerols from stearate to lignocerate was accomplished by applying the compounds to silica gel and exposing them to hydrogen chloride gas at -75 degrees C. The purity of the compounds was checked by boric acid impregnated thin-layer chromatography, 13C NMR, and reverse-phase high-pressure liquid chromatography. Differential scanning calorimetry and X-ray diffraction techniques were used to study the polymorphism of the compounds. In the beta phase obtained from solvent of crystallization, the acyl chain packing was in a two-dimensional oblique lattice with specific chain-chain interactions with a tilt angle of 55.4 degrees from the bilayer plane. The thickness of the region containing two glycerol head groups was 12.7 A. The phase transition enthalpy of melting for the beta phase was 1.06 kcal/mol of CH2. On being cooled these compounds crystallized reversibly to an unstable alpha phase, which on being further cooled underwent a second crystallization to a beta or beta' phase. The thermodynamic parameters and long spacings of these compounds in both beta and alpha phases were linear, indicating isostructural packing in each phase. The enthalpy of the melting transition of the alpha phase was 0.69 kcal/mol of CH2. In this phase, the chains were packed in a hexagonal lattice with nonspecific chain-chain interactions. The thickness of the head-group region (12.2 A) and the tilt angle (55 degrees) of the acyl chains in the alpha phase were very similar to those in the beta phase.

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Section: Methodsmentioning

confidence: 99%

Synthesis and polymorphism of 3-acyl-sn-glycerols

et al. 1985

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“…By no means are all the liquid molecules in coal held in pores as these have been defined hitherto in coal chemistry. 30 The molecules could be more easily extracted when the macromolecular matrix has been swollen by a solvent. 31 In the present work presoaking was done to provide sufficient time for the solvents to be completely admitted into the micropores and to attain maximum imbibitions to the macromolecular matrix of coal.…”

Section: Effect Of Pre-soakingmentioning

confidence: 99%

Depolymerization Study of Pakistani Lignite Coal Influence of Pre‐treatments on Product Slate

Ahmad

Khan

Shakirullah

et al. 2004

J Chinese Chemical Soc

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Influence of pretreatments, i.e., demineralization and pre‐soaking in some solvents on the yields of liquefied products obtained from hydro‐depolymerization of Pakistani coal in a pool of hydrogen has been discussed. Results of hydrogenation experiments demonstrated that demineralizing the coal sample prior to liquefaction caused the yields to decrease compared with the virgin coal samples. The contribution of mineral matter of coal has been evaluated by comparing the yields of liquid products of virgin and leached samples. Increase in the yields obtained from the hydrogenation experiments of swollen coal samples was not satisfactorily significant.

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Solvent extraction study of a whole, low‐temperature tar

Ahmed

Vahrman

1966

J. Appl. Chem.

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A low-temperature tar was sub-divided, entirely by solvent extraction, into the following fractions: crude phenols and bases; hydrocarbons of different types-aliphatic, hydroaromatic and aromatic; and a neutral, oxygen-containing aromatic fraction. The three hydrocarbon materials and the last-named were obtained from the neutral tar oil (light petroleum-soluble) by a series of partition extractions with the solvent pair, furfural/light petroleum, petroleum, using definite ratios of tar/solvents. These four fractions corresponded closely to those previously obtained by adsorption chromatography.

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Cited by 4 publications

References 0 publications

Synthesis and polymorphism of 3-acyl-sn-glycerols

Synthesis and polymorphism of 3-acyl-sn-glycerols

Depolymerization Study of Pakistani Lignite Coal Influence of Pre‐treatments on Product Slate

Solvent extraction study of a whole, low‐temperature tar

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