Organic solid

1 Organic Solids. - NMR has been used to study the molecular 

The stereolabile helical enantiomers of dimesityl sulfoxide and sulfone have been characterized by C CPMAS NMR, which show that the helical enantiomers are stable in the crystalline state. 

A study of the tautomerism of dehydroacetic acid, using C CPMAS and other techniques, has showed that this compound exists as the 3-acetyl-4-hydroxy-6-methyl-2/f-pyran-2-one in the solid state. 

Two polymorphic forms of cw-cinnamic acid have been characterized using 3C CPMAS NMR.  

The 3-alkyl, benzyl and phenyl derivatives of l-(2-hydroxy-4-bromophenyl)-3-methyl-4-imidazolin-2-one have been studied by solid-state C CPMAS NMR. The differences in chemical shifts A = 5(liquid) — 8(solid) are significant for aromatic carbons C3 ( — 2.9 ppm), C4 (3.6 ppm) and C5 (—3.9 ppm) and C7 (—1.5 ppm), which are adjacent to N1-C4, and are subject to the largest changes of the environment during reorientation of the imidazolin-2-one moiety. 

Solvent molecules of water and acetone trapped in calix[4]hydroquinone supramolecular nanotubes have been studied by solid state and fast MAS NMR and DFT calculations. It has been shown that both water and acetone molecules occupy well-defined average positions, but undergo fast reorientation motions during which their protons interchange their positions. 

The nature of the phase transitions and proton-deuteron dynamics in the crystals of 9-hydroxyphenalenone derivatives have been investigated by means of solid state NMR spectroscopy. It was found that the antiferroelectric ordering of deuterons along the hydrogen bonds in 5-methyl-9-deuterioxyphenalenone and 5-bromo-9-deuterioxyphenalenone occurs below the phase transition temperatures at 44 K and 34 K, respectively. The microscopic origin of the incommensurate modulation in 5-bromo-9-deuterioxyphenalenone below 34 K was attributed to slight rotational displacements, which are fixed at commensurate angles below the lock-in transition at 22 K. 

The dehydration of a thiamine hydrochloride (vitamin Bi) hydrate, commonly referred to as the monohydrate, was investigated by solid state NMR and X-ray diffraction. The hydrate was classified as a nonstoichiometric solvate since the water content depends on the water vapor pressure of the surrounding atmos- 

Evidence for reorientation of imidazolium rings in imidazolium methylsulfon-ate has been demonstrated using sohd state NMR. This material is a model system for new proton-conducting materials based on imidazole. Two advanced NMR methods, including and recoupled polarisation transfer 

Attempts have also been made to design one-dimensional organic superconductors based on donor-acceptor interaction (Bechgaard Jerome, 1982). For this purpose it 

Typically foods, feedstuffs, leaves, plants, biological solids, tissue, polymers, etc. Prior to solubilisation these types of sample generally require destruction via wet digestion or ashing in a muffle furnace. A typical procedure featuring a nitric/perchloric acid mixture is reproduced below. 

Electronic processes in crystalline organic solids have been described extensively by Pope and Swenberg (1982). Here we summarize the results of studies on the electronic properties of the solid phase of some of the liquids which were discussed in the preceding chapters. 

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The theory of the action of drying agents has been considered in Section 1,20. We are now concerned with the practical methods for the removal of water from organic solids and liquids and from solutions of... 

G. Tsoucaris, in G. R. Deskaju, ed.. Organic Solid State Chemisty, Elsevier, Amsterdam, 1987, p. 207. 

G. I. Stegeman and W. TormeUas, E/ectrica/, Optical, and Magnetic Properties of Organic Solid State Materials, Materials Research Society, Pittsburgh, 1994, pp. 397-412. 

TABLE 2-197 Specific Heats of Organic Solids Continued)... 

Heat-transfer coefficients in steam-tube dryers range from 30 to 85 J/(m s K). Coefficients will increasewith increasing steam temperature because of increased heat transfer by radiation. In units carrying saturated steam at 420 to 450 K, the heat flux UAT will range from 6300 J/(m s) for difficult-to-diy and organic solids and to 1890 to 3790 J/(m s) for finely divided inorganic materials. The effect of steam pressure on heat-transfer rates up to 8.6 X 10 Pa is illustrated in Fig. 12-71. 

Organic Solids A few organic compounds decompose before melting, mostly nitrogen compounds azides, diazo compounds, and nitramines. The processes are exothermic, classed as explosions, and may follow an autocatalytic law. Temperature ranges of decomposition are mostly 100 to 200°C (212 to 392°F). Only spotty results have been obtained, with no coherent pattern. The decomposition of malonic acid has been measured for both the solid and the supercooled liquid. The first-order specific rates at 126.3°C (259.3°F) were 0.00025/min for solid and 0.00207 for liquid, a ratio of 8 at II0.8°C (23I.4°F), the values were 0.000021 and 0.00047, a ratio of 39. The decomposition of oxalic acid (m.p. I89°C) obeyed a zero-order law at 130 to I70°C (266 to 338°F). 

One of the most widely applicable and most commonly used methods of purification of liquids or low melting solids (especially of organic chemicals) is fractional distillation at atmospheric, or some lower, pressure. Almost without exception, this method can be assumed to be suitable for all organic liquids and most of the low-melting organic solids. For this reason it has been possible in Chapter 4 to omit many procedures for purification of organic chemicals when only a simple fractional distillation is involved - the suitability of such a procedure is implied from the boiling point. 

MLVSS Mixed Liquor Volatile Suspended Solids - the volume of organic solids that can evaporate at relatively low temperatures (550 C) from the mixed liquor of an aeration tank. This volatile portion is used as a measure or indication of microorganisms present. Volatile substances can also be partially removed by air stripping. 

R. Saito, M. Fujita, G, Dresselhaus, and M. S. Dresselhaus, In Electrical, Optical and Magnetic Properties of Organic Solid State Materials, MRS Symposia Proceedings, Boston. Edited by L. Y. Chiang, A. F. Garito, and D. J. Sandman, vol, 247, p. 333, Pittsburgh, PA, Materials Research Society Press (1992),... 

High-Resolution Solid-State NMR Study of Reversible 1,5-Proton Shifts in Organic Solids [90MRC(S)29] NMR of Pyrazoles ... 

Several techniques are usually employed to induce crystallization from saturated solutions of organic solids. The introduction of seed crystals will invariably work, although with new compounds such crystals are not available. Seeding with crystals of a... 

Professor of Physics Professor of Materials Institute for Polymers and Organic Solids University of California, Santa Barbara and... 

M. Bcrggren, A. Dodabalapur, R. E. Slusher, Organic solid-state lasers with imprinted gratings on plastic substrates, Appl. Phys. Leu. 1998, 72, 410. 

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