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The study describes the solid state behaviour, and the thermal and structural features of four monosolvates of cinacalcet hydrochloride with acetic acid, chloroform, 1,4-dioxane, and tetrachloromethane, and summarises the transformation and production pathways of the seven crystal forms of this promising drug compound (calcimimetic). The solvates were identified and characterised by hot-stage microscopy, differential scanning calorimetry, thermogravimetric analysis, FT-infrared and Raman spectroscopy, powder diffractometry, and the structure of the acetic acid solvate was determined by single crystal X-ray diffraction. All solvates are unstable when removed from the mother liquor and desolvate to form II. To our knowledge, phase pure samples of this metastable but kinetically stable form are only obtainable viadesolvation of one of the solvates.Thermoanalytical data and a conformation and packing analysis of the acetic acid solvate and the polymorphs indicate that the desolvation is a destructive process forming an isotropic intermediate state with high molecular mobility. Therefore the desolvation process results in the kinetic form II, which is structurally less similar to the solvate than the thermodynamically stable form III°. The study demonstrates that in spite of strong structural similarities between a solvate and a polymorph we can obtain a polymorph with less structural resemblance to the solvent adduct if the structure collapses during the desolvation process. [ABSTRACT FROM AUTHOR]

The 1 : 1 complex of styrene with acetylene has been studied by mass selective low- and high-resolution UV resonance-enhanced two-photon ionisation (R2PI) spectroscopy combined with genetic-algorithm-based computer-aided fit of the spectra with partial rotational resolution, and high level ab initio quantum chemistry calculations. Two stable conformeric geometries of the 1 : 1 complex of styrene and acetylene have been theoretically found: one with acetylene binding to styrene as a proton donor, and one with acetylene acting as a proton acceptor. From the analysis of the vibronic structure of the S1← S0 spectrum and the fit of the highly resolved spectrum of the 000 origin band of the complex it is shown that the favoured conformation is the one in which acetylene binds to the benzene ring of styrene through formation of a non-conventional hydrogen bond of C–H⋯π type with no marked change of the transition moment orientation of styrene. The styrene moiety remains planar and the acetylene molecule is tilted by a small angle of 4° relative to the C6 symmetry axis of the benzene ring, most likely due to the reduced symmetry of the benzene ring π electrons rather than to a direct interaction with the vinyl group. [ABSTRACT FROM AUTHOR]

This paper discusses the drying processes of four different designs of household clothes tumbler dryer using electric power input. The relative advantages and disadvantages and the energy analyses of the dryers are presented. A parametric study was conducted to assess the effects of different variables on energy efficiency and specific moisture extraction rate. It is shown that the conventional tumbler dryer technology can be improved significantly by the use of heat-recovery heat exchangers. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Attempts to co-crystallise 3-arylbutanoic acid derivatives with isonicotinamide have led to co-crystals and novel polymorphs of the isonicotinamide co-former appearing under similar crystallisation conditions. [ABSTRACT FROM AUTHOR]