Physicochemical properties crystallinity

Several physicochemical properties of dietary fiber contribute to its physiological role. Water-holding capacity, ion-exchange capacity, solution viscosity, density, and molecular kiteractions are characteristics determined by the chemical stmcture of the component polysaccharides, thek crystallinity, and surface area. 

Physicochemical Properties White crystalline powder, granular, or tablets... 

Physicochemical Properties White crystalline solid powder or granular, ion- toxic and odorless ... 

Chemical development Proof of structure and configuration are required as part of the information on chemical development. The methods used at batch release should be validated to guarantee the identity and purity of the substance. It should be established whether a drug produced as a racemate is a true racemate or a conglomerate by investigating physical parameters such as melting point, solubility and crystal properties. The physicochemical properties of the drug substance should be characterized, e.g. crystallinity, polymorphism and rate of dissolution. 

Chromium zeolites are recognised to possess, at least at the laboratory scale, notable catalytic properties like in ethylene polymerization, oxidation of hydrocarbons, cracking of cumene, disproportionation of n-heptane, and thermolysis of H20 [ 1 ]. Several factors may have an effect on the catalytic activity of the chromium catalysts, such as the oxidation state, the structure (amorphous or crystalline, mono/di-chromate or polychromates, oxides, etc.) and the interaction of the chromium species with the support which depends essentially on the catalysts preparation method. They are ruled principally by several parameters such as the metal loading, the support characteristics, and the nature of the post-treatment (calcination, reduction, etc.). The nature of metal precursor is a parameter which can affect the predominance of chromium species in zeolite. In the case of solid-state exchange, the exchange process initially takes place at the solid- solid interface between the precursor salt and zeolite grains, and the success of the exchange depends on the type of interactions developed [2]. The aim of this work is to study the effect of the chromium precursor on the physicochemical properties of chromium loaded ZSM-5 catalysts and their catalytic performance in ethylene ammoxidation to acetonitrile. 

Food materials (ingredients or whole systems) can be composed of matter in one, two, or all three physical states solid (crystalline or amorphous or a combination of both), liquid, and gas. The crystalline state is an equilibrium solid state, whereas the amorphous glassy state is nonequilibrium solid state. The main transitions that occur between the physical states of materials of importance to foods are summarized by Roos and Karel (1991) and Roos (2002). The most important parameters affecting the physical state of foods, as well as their physicochemical properties and transition temperatures, are temperature, time, and water content (Slade and Levine, 1988 Roos, 1995). Pressure is not included in this list, as food materials usually exist under constant pressure conditions. 

Abstract Layered double hydroxides (LDHs) comprise au extensive class of materials that are very easy to synthesize in the laboratory, albeit not always as pure phases. In this chapter, we review the wide variety of methods that are available for the synthesis of LDHs and focus on the way in which the physicochemical properties of the materials (such as phase piuity, crystallinity and surface area) vary with synthesis method. The flexibility of the different methods is also discussed some methods can be used to synthesize LDHs containing a wide range of constituent cations and anions, whilst others are more limited in scope. In some cases, the potential for scale-up of a method to produce larger quantities of material is also noted. 

The most commonly employed crystalline materials for liquid adsorptive separations are zeolite-based structured materials. Depending on the specific components and their structural framework, crystalline materials can be zeoUtes (silica, alumina), silicalite (silica) or AlPO-based molecular sieves (alumina, phosphoms oxide). Faujasites (X, Y) and other zeolites (A, ZSM-5, beta, mordenite, etc.) are the most popular materials. This is due to their narrow pore size distribution and the ability to tune or adjust their physicochemical properties, particularly their acidic-basic properties, by the ion exchange of cations, changing the Si02/Al203 ratio and varying the water content. These techniques are described and discussed in Chapter 2. By adjusting the properties almost an infinite number of zeolite materials and desorbent combinations can be studied. 

The physicochemical properties of explosives are fundamentally equivalent to those of propellants. Explosives are also made of energetic materials such as nitropolymers and composite materials composed of crystalline particles and polymeric materials. TNT, RDX, and HMX are typical energetic crystalline materials used as explosives. Furthermore, when ammonium nitrate (AN) particles are mixed with an oil, an energetic explosive named ANFO (ammonium nitrate fuel oil) is formed. AN with water is also an explosive, named slurry explosive, used in industrial and civil engineering. A difference between the materials used as explosives and propellants is not readily evident. Propellants can be detonated when they are subjected to excess heat energy or mechanical shock. Explosives can be deflagrated steadily without a detonation wave when they are gently heated without mechanical shock. 

Table 10.7 shows the physicochemical properties of the crystalHne materials used as oxidizers. Potassium and sodium are combined with nitrate or perchlorate to form stabilized crystalline oxidizers. Metal oxides are formed as their combustion products. On the other hand, ammonium ions are combined with nitrate or perchlorate to form stabilized crystalline oxidizers such as NH4NO3 and NH4CIO4 without metal atoms. When these oxidizers are decomposed, no solid products are formed. As discussed in Section 10.1.1, for the oxidizers used for propulsion, such as in propellants for rockets and guns, the molecular mass of the combustion products needs to be as low as possible. 

Hydrocarbon polymers (HCP) are used not only as fuel components but also as binders of crystalline oxidizers and metal powders in the formulation of pyrolants, similar to composite propellants and plastic-bonded explosives. There are many types of HCP, the physicochemical properties of which are dependent on their molecular structures. The viscosity, molecular mass, and functionality of the poly-... 

Tables 5.1 and 5.2 hst the main physicochemical properties of the modified zeolite characterized by a series of analyzing methods. XRF, XRD, and Al NMR results listed in Table 5.1 showed that with the increasing intensity of CP treatment, nonframework aluminum was ranoved gradually with httle influence on zeohte framework (unit cell size (UCS) changed little), thus the relative crystallinity increased. The removal of nonframework aluminum can also be verified by the FT-IR results shown in Figure 5.1, in which it can be seen that after CP treatment the intensity of the small peak at wave number 3660-3690 cm characterizing nonframework hydroxyl groups decreased step by step.

In diffuse reflection spectroscopy, the spectrometer beam is reflected from, scattered by, or transmitted through the sample, whereas the diffusely scattered light is reflected back and directed to the detector. The other part of the electromagnetic radiation is absorbed or scattered by the sample [124,125]. Changes in band shapes or intensity as well as signal shifts can be affected by morphological and physicochemical properties of the sample or combinations thereof (e.g., chemical absorptions, particle size, refractive index, surface area, crystallinity, porosity, pore size, hardness, and packing density [126]). Therefore, NIR diffuse reflection spectra can be interpreted in dependence of various physical parameters [127]. 

Since the energetics of nitropolymer propellants composed of NC-NG or NC-TMETN are limited due to the limited concentration of oxidizer fragments, some crystalline particles are mixed within these propellants in order to increase the thermodynamic energy or specific impulse. The resulting class of propellants is termed composite-modified double-base (CMDB) propellants . The physicochemical properties of CMDB propellants are intermediate between those of composite and double-base propellants, and these systems are widely used because of their great potential to produce a high specific impulse and their flexibility of burning rate. 

Given the complexity that arises from the multitude of interacting variables associated with DPI systems, there are very few excipients that have been incorporated into DPI formulations. Examples of commonly marketed products are listed in Table 2. Lactose has many benefits including a well-established safety profile, low cost, and wide availability. Physicochemical properties of lactose are also relatively desirable from a DPI formulation standpoint smooth surfaces, crystalline, and moderate flow properties. However, lactose may not be suitable for some active... 

It is important to characterize the physicochemical properties of the suspensions well, so that the PK data can be interpreted appropriately. Typical characterization of the drug substance includes purity, residual solvents, aqueous solubility pro Lie (pH 2, FaSSIF), crystallinity (XRPD/DSC), particle size, pl and logP. For solution formulations at various stages of discovery studies, dose analysis is essential, and for efLcacy assessment and toxicology studies, chemical stability for the... 

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