Crystallization melt type

Two different types of crystals were obtained by cooling crystallization of qulzalofop-ethyl dissolved In ethyl alcohol at room temperature. As shown In Photograph 1, one type consists of plate-llke crystal of 20-50 jum In size and another one Is halrllke crystal of 1-2 pm In short axis size. As shown In Figure 1, different X-ray patterns were obtained for the two crystals. Melting points and heats of fusion were also measured for the two crystal types by DTA and DSC, which are listed In Table I. These results Indicate that the different shapes of the two crystal types are related to differences In crystal lattice. 

Molecular rotation In a normal crystal every atom occupies a precise mean position, about which it vibrates to a degree depending on the temperature molecules or polyatomic ions have precisely defined orientations as well as precise mean positions. When such a crystal is heated, the amplitude of the thermal vibrations of the atoms increases with the temperature until a point is reached at which the regular structure breaks down, that is, the crystal melts. But in a few types of crystal it appears that notation of molecules or polyatomic... 

Observed correlation between compound formation mode (congruent vs. incongruent melting) against crystal structure type of AB2 compounds. The underlined compounds are suspect either with the liquidus curve determination or the crystal structure type. 

Although phase diagrams show the existence of ABr,, AB.,, and ABn compounds, congruent-melting type compounds belonging to these stoichiometries are relatively few in number and their crystal structures are poorly characterized. Thus, no correlation can be made between them. 

The melting temperatures for the thirty-one elements, whose inelastic neutron scattering data are available, were calculated and compared against the observed melting temperatures as shown in Table 1. In this calculation, the thirty-one elements are sorted into three groups according to their crystal structure type. Different correction factor, A,... 

In 200 ml of methanol was dissolved 20.0 g of 5- l-hydroxy-2-[N-benzyl-2-(2-methoxyphenoxy)ethylamino]ethyl -2-methyl-benzenesulfonamide. After adding thereto 20 ml of ethanol containing about 10% hydrogen chloride and 1.0 g of 10% palladium charcoal, the mixture was shaken in hydrogen gas stream. When the absorption of hydrogen stopped, the catalyst was filtered away and the filtrate was distilled off under reduced pressure. The residue was dissolved in 100 ml of ethanol while it was hot and the solution was allowed to stand overnight in ice chamber, whereby 12.8 g of the a-type crystals of 5- 1-hydroxy-2-[2-(2-methoxyphenoxy)ethylamino]ethyl>-2-methylbenzenesulfonamide were obtained as the colorless crystals, melting point 169°-171°C. 

Most of the poly(etherketone-carborane)s so far prepared are non-crystalline and thus readily soluble in organic solvents such as chloroform or NMP, from which tough, coherent films and coatings can be obtained by solvent evaporation. However, we have found two polymers of this type, both derivatives of p-carborane, which display significant levels of crystallinity.8 Thus, the semi-aliphatic polymer derived from bis(4-phenoxyphenyl)-p-carborane (3) and hexadecanedioic acid (6) undergoes solvent-induced crystallisation on contact with NMP, and then shows a crystal melting point of 122 °C. 

Raman spectral-band frequencies for poly (thietane) as a crystallized melt annealed at 62° satisfy the rules for a longitudinal acoustic-mode frequency for deducing thickness. The morphology and physical properties of isoprene thietane block copolymers have been studied. Potential energies have been calculated for helical- and glide-type conformations of poly (thietane), and the conformations of the homopolymer have been calculated. ... 

Wissbrun earlier observed a very long relaxation time and high elasticity for anisotropic melts of aromatic polyesters, as well as several other types of flow anomalies. Unfortunately, in most of these earlier studies, the rheological behavior of liquid crystal melts of polymers could not be directly compared with that of the isotropic phase of the same polymers because of their high clearing temperatures. 

In order to model the flow behavior of molten silicate suspensions such as magmas and slags, the rheological behavior must be known as a function of the concentration of suspended crystals, melt composition, and external conditions. We have determined the viscosity and crystallization sequence for a Kilauea Iki basalt between 1250°C and 1149°C at 100 kPa total pressure and f02 corresponding to the quartz-fayalite-magnetite buffer in an iron-saturated Pt30Rh rotating cup. viscometer of the Couette type. The apparent viscosity varies from 9 to 879 Pa.s. The concentration of suspended crystals varies from 18 volume percent at 1250°C to 59 volume percent at 1149 C. The molten silicate suspension shows power-law behavior ... 

We may wonder what happens at molecular level when ice, a crystal, melts and becomes a liquid, hi most hquids the correlations of positions and orientations of constituent molecules rapidly fall off when the distance between them increases. Furthermore, correlations between nearby molecules display rapid fluctuations that make the hquid a fluid. Most of these hquids, however, consist of molecules that mainly interact via weak Van der Waals forces, which are, at room temperature, much less directional than H-bonds, the only molecular interactions established by H2O molecules in liquid water. The fnst idea that usually comes to mind is then that a relatively great proportion of H-bonds are broken in liquid water, so that HjO molecules may gain some independence, making these correlations fall off rapidly with distance. Experiments teU us that the proportion of broken H-bonds is much too small in hquid water to be at the origin of its fluidity. We rapidly examine the fnst type of such experiments, thermodynamics, and describe in more detail a more informative type of experiment IR spectroscopy, from which will emerge an image of the H-bond network of hquid water... 

White powder, compact or loose depending on the method of preparation. M.p. 3050°C, b.p. 4400°C d 9.87. Crystal structure type Cl (fluorite type). Almost insoluble in acids when calcined at high temperatures, although readily decomposed in bisulfate melts or by evaporation with cone. H3SO4. In contrast to TiO3 and ZrOg, does not form salts with basic oxides and is therefore insoluble in molten NaOH or NagCOg. The oxide prepared by calcination of the oxalate at 500°C may be dissolved by peptization with dilute hydrochloric acid. 

Bronze-colored powder. M.p. 2950°C d 5.21. Somewhat dissociated at the melting point. Crystal structure type B1 (NaCl type). This structure holds for a wide range of compositions (TiNi.o-TiNo.4). Veiy good electrical conductor. 

During crystallization of type II melts with 5-30 wt% of PI, initially a homogeneous solid / -solution is formed (enriched PE), which becomes unstable... 

The polymer was produced by heating of dichloranhydride of tere-phthaloyl-bis( -oxybenzoic) acid, l,l,3,3-tetramethylene-l,3-bis-(3-hydroxypropyl)-bis-siloxane and triethylamine in ratio 1 1 2, respectively in environment of chloroform in argon atmosphere. The studied were the fibers obtained by mechanical extrusion from liquid-crystal melt when heating initial sample. The polymer s characteristic stmcture was of smectic type with folding location of molecules within layers. 

---