Crystalline Acetone Research Articles

In Situ Measure of Intrinsic Bond Strength in Crystalline Structures: Local Vibrational Mode Theory for Periodic Systems.

The local vibrational mode analysis developed by Konkoli and Cremer has been successfully applied to characterize the intrinsic bond strength via local bond stretching force constants in molecular systems. A wealth of new insights into covalent bonding and weak chemical interactions ranging from hydrogen, halogen, pnicogen, and chalcogen to tetrel bonding has been obtained. In this work we extend the local vibrational mode analysis to periodic systems, i.e. crystals, allowing for the first time a quantitative in situ measure of bond strength in the extended systems of one, two, and three dimensions. We present the study of one-dimensional polyacetylene and hydrogen fluoride chains and two-dimensional layers of graphene, water, and melamine-cyanurate as well as three-dimensional ice I h and crystalline acetone. Besides serving as a new powerful tool for the analysis of bonding in crystals, a systematic comparison of the intrinsic bond strength in periodic systems and that in isolated molecules becomes possible, providing new details into structure and bonding changes upon crystallization. The potential application for the analysis of solid-state vibrational spectra will be discussed.

IR spectra and properties of solid acetone, an interstellar and cometary molecule

Mid-infrared spectra of amorphous and crystalline acetone are presented along with measurements of the refractive index and density for both forms of the compound. Infrared band strengths are reported for the first time for amorphous and crystalline acetone, along with IR optical constants. Vapor pressures and a sublimation enthalpy for crystalline acetone also are reported. Positions of 13C-labeled acetone are measured. Band strengths are compared to gas-phase values and to the results of a density-functional calculation. A 73% error in previous work is identified and corrected.

Energetic Derivatives of 4, 4′,5, 5′‐Tetranitro‐2, 2′‐bisimidazole (TNBI)

Abstract4, 4′,5, 5′‐Tetranitro‐2, 2′‐bisimidazole (TNBI) was synthesized by nitration of bisimidazole (BI) and recrystallized from acetone to form a crystalline acetone adduct. Its ammonium salt (1) was obtained by the reaction with gaseous ammonia. In order to explore new explosives or propellants several energetic nitrogen‐rich 2:1 salts such as the hydroxylammonium (3), guanidinium (4), aminoguanidinium (5), diaminoguanidinium (6) and triaminoguanidinium 7 4, 4′,5, 5′‐tetranitro‐2, 2′‐bisimidazolate were prepared by facile metathesis reactions. In addition, methylated 1, 1′‐dimethyl‐4, 4′,5, 5′‐tetranitro‐2, 2′‐bisimidazole (Me2TNBI, 8) was synthesized by the reaction of 2 and dimethyl sulfate. Metal salts of TNBI can also be easily synthesized by using the corresponding metal bases. This was proven by the synthesis of pyrotechnically relevant dipotassium 4, 4′,5, 5′‐tetranitro‐2, 2′‐bisimidazolate (2), which is a brilliant burning component e.g. in near‐infrared flares. All compounds were characterized by single crystal X‐ray diffraction, NMR and vibrational spectroscopy, elemental analysis and DSC. The sensitivities were determined by BAM methods (drophammer and friction tester). The heats of formation were calculated using CBS‐4M electronic enthalpies and the atomization method. With these values and mostly the X‐ray densities different detonation parameters were computed by the EXPLO5 computer code. Due to the great thermal stability and calculated energetic properties, especially guanidinium salt 4 could be served as a HNS replacement.

Molecular dynamics in crystalline acetone studied by dielectric spectroscopy and neutron diffraction

Dielectric spectroscopy and neutron diffraction experiments in acetone have been performed in order to clarify the dynamical behavior and the structural changes associated to the unsolved thermal transition that takes place in the solid state around 130 K. The combination of dielectric experiments with neutron diffraction reveals the existence of a dielectric process in the stable crystalline phase of acetone. The evolution with temperature of the dielectric process, within the temperature range where the peak of the heat capacity was reported, supports that the transition is not of order–disorder type. The origin of the dielectric dispersion has been assigned to structural defects in the orthorhombic crystal phase of acetone.

Structure of the acetone liquid/vapor interface

The structure of the liquid/vapor interface of acetone is investigated theoretically by molecular dynamics simulation and experimentally by infrared-visible sum frequency vibrational spectroscopy. The simulation yields the molecular orientational distribution at the liquid surface. In conjunction with the ab initio calculation, the sum-frequency vibrational spectra for the interface is then computed, allowing a direct comparison to the measured spectra. As the calculation agrees well with the experiment, we can conclude that the molecules at the liquid surface are polar ordered, with one of the methyl groups pointing away from the bulk and the molecular plane perpendicular to the surface. This orientation is similar to that of molecules in the layer planes of crystalline acetone. Together with the appreciable surface tension of acetone, it suggests that the acetone liquid surface has a more ordered structure than the bulk and is more or less crystal-like.

Purification of Dirithromycin. Impurity Reduction and Polymorph Manipulation

The manufacture of dirithromycin [9S(R)-9-deoxo-11-deoxy-9,11-[imino[2-(2-methoxyethoxy)ethylidene]oxy]erythromycin] from commercially available erythromycin A results in a drug substance containing impurities at the level of several percent. A five-step plan for the development of a commercial-scale recrystallization procedure is presented. A purification system for dirithromycin which utilizes the crystalline acetone solvate and exemplifies this plan is described. Physical characterization data for this solvate are included. The solubility of the acetone solvate in water−acetone mixtures is at a maximum at a ratio of 1:9 v/v and exhibits a parabolic relationship with temperature such that, in a solvent composition of 2:1, its solubility is at a minimum at 40 °C. The adduct of erythromycylamine and acetone was found to exist in solution as an equilibrium between the tetrahydro-1,3-oxazine and imine forms.

Librational spectra of pure and CCl4 diluted acetone measured by inelastic neutron scattering

Inelastic neutron scattering spectra of matrix-isolated and bulk acetone are reported. Acetone in frozen CCl4 solutions shows a doubly split transition at 122 and 140 cm−1, which is assigned to the methyl torsions of isolated individual molecules. In bulk acetone four peaks in the region of torsional transitions between 100 and 184 cm−1 can be distinguished from low-lying phonons at 34, 51 and 70 cm−1. The torsions are tentatively assigned to the methyl groups of coupled dimers of equivalent molecules in crystalline acetone. After co-condensation with argon and evaporation of the rare gas a highly perturbed metastable acetone solid is observed.-All assignments are based on the isotopic shifts observed in CD3COCD3. It is shown that the observed positions and splittings of the librations in bulk acetone are then consistent with the librations in bulk acetone are then consistent with the occurence of just one single tunnel transition at 96 MHz reported in [1].

Out-of-plane vibrations of acetone oxime-Do and -D6

The Raman and polarized i.r. spectra of crystalline acetone oxime-d 6 (AD-d 6 ) were recorded and used for a complete assignment of the fundamental vibrations. Experimental evidence is presented for the assignment of the 650 cm −1 infrared absorption band of AO-d 0 and -d 6 crystals to a hot transition of the OH out-of-plane bending vibration. A simplified force field is proposed for the out-of-plane vibrations of the molecule.

On the vibrational assignment and structure of crystalline acetone oxime

On the vibrational assignment and structure of crystalline acetone oxime

Vibrational spectra and structure of nitrogen containing molecules—III. Acetone azine and acetone azine- d12

The i.r. spectra of (CH 3) 2CNNC(CH 3) 2 and (CD 3) 2CNNC(CD 3) 2 have been studied from 4000 to 300 cm −1 in all three physical states. Absorption spectra for the polycrystalline samples were also obtained down to 33 cm −1. Raman spectra for liquid and crystalline acetone azine and acetone azine- d 12 were recorded between 4000 and 100 cm −1. Since mutual exclusion was observed for the i.r. and Raman bands assigned to the skeletal modes of acetone azine, the spectral data have been interpreted in terms of C 2 h molecular symmetry. An assignment of the fundamental vibrations is based upon the observed isotopic shift ratios, depolarization measurements, relative band intensities and positions. The methyl torsional modes were assigned to bands at 235 and 215 cm −1, respectively, in the Raman spectrum of crystalline acetone azine. The frequencies associated with the CN and NN stretching modes of acetone azine suggest the π electrons may not be localized and this observation is consistent with the bond orders for the CN (1.9) and NN (1.5) groups calculated from simple molecular orbital theory. The results of the present study are compared with the data recently reported for tetramethylhydrazine and tetramethyltetrazine.

ChemInform Abstract: POLARIZED INFRARED SPECTRUM OF CRYSTALLINE ACETONE

Chemischer InformationsdienstVolume 6, Issue 13 Physical Organic Chemistry ChemInform Abstract: POLARIZED INFRARED SPECTRUM OF CRYSTALLINE ACETONE P. F. KRAUSE, P. F. KRAUSESearch for more papers by this authorB. G. GLAGOLA, B. G. GLAGOLASearch for more papers by this authorJ. E. KATON, J. E. KATONSearch for more papers by this author P. F. KRAUSE, P. F. KRAUSESearch for more papers by this authorB. G. GLAGOLA, B. G. GLAGOLASearch for more papers by this authorJ. E. KATON, J. E. KATONSearch for more papers by this author First published: April 1, 1975 https://doi.org/10.1002/chin.197513057AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume6, Issue13April 1, 1975 RelatedInformation

Polarized infrared spectrum of crystalline acetone

Through the use of oriented polycrystals, the polarized infrared spectrum of crystalline acetone has been investigated. The results have been satisfactorily used to deduce both site and possible factor group symmetries. In addition, the oriented gas model has been used as a means of classifying vibrations according to the various molecular symmetry species, thereby clarifying the vibrational assignments of three low frequency modes. This has been accomplished through the use of experimentally determined cosine-squared ratios of the pertinent symmetry species.

Electronic-Relaxation Processes in Acetone

The emission properties of acetone and acetone-d6 have been studied in order to investigate the mechanisms for relaxation of electronic excitation. The results are summarized in Fig. 2 and Table I. The phosphorescence lifetime of acetone at 77°K in ether—IPA glass was 4×10−4 sec and the quantum yield for phosphorescence was ΦP=0.03±0.01. Deuteration of the acetone increased the phosphorescence lifetime to 1×10−3 sec and the quantum yield to ΦP=0.08±0.02. The phosphorescence of acetone was found to be quenched by the addition of pentene−2 to the rigid solution, but the fluorescence was unaffected. From the quenching data it is concluded that the excited-singlet→excited-triplet intersystem-crossing quantum yield is ΦIC=1.0±0.1, independent of temperature between 298° and 77°K. The intersystem-crossing rate constant is kIC=4×107 sec−1 and is not affected by deuteration. The excited triplet state is populated with nearly unit efficiency upon excitation of acetone to its lowest singlet state, and therefore the low phosphorescence yield, even in acetone-d6, indicates that radiationless transitions from the triplet state to the ground state are primarily responsible for determining the lifetime of the lowest triplet state. A medium effect on the acetone phosphorescence lifetime at 77°K was observed; it was found to vary from 3×10−4 in glycerine solutions to 1×10−3 sec in crystalline acetone. The triplet-state lifetime in crystalline acetone decreased only slightly upon increasing the temperature to just below the melting point of crystalline acetone, but in the case of glycerine solutions, the triplet-state lifetime decreased by at least a factor of 10 in raising the temperature from 77° to 200°K, even though the glycerine remained quite solid. The fluorescence quantum yield in liquid solutions was found to be independent of solvent at 25°C. The lifetime of the lowest (n, π*) singlet state of acetone is primarily determined by intersystem crossing to the lower-lying excited triplet state and is therefore τS=2.5×10−8 sec. The quantum yield for acetone fluorescence at room temperature was found to be ΦF=0.01±0.003. No deuterium effect on ΦF was observed and therefore it may be concluded that either there is no deuterium effect on the rate of internal conversion from the excited singlet state to the ground state, or, what is more likely, that internal conversion is much slower than intersystem crossing which is not affected by deuteration. The fluorescence spectra of acetone and acetone-d6 were found to be identical under all conditions, as were the phosphorescence spectra of acetone and acetone-d6. The phosphorescence was found to be polarized perpendicular to the lowest singlet—singlet absorption, consistent with theoretical predictions.