Physical Characteristics 3, Chemical Properties

The process of lyophilization is affected by the vial s dimensions, physical characteristics, chemical properties, and interactions with both the drug product contained and the chamber shelf on which the vial rests. The text that follows will detail various key characteristics that can be either an advantage or disadvantage to the lyophilization process. 

Crude oils present a wide variety of physical and chemical properties. Among the more important characteristics are the following ... 

The glass-ceramic phase assemblage, ie, the types of crystals and the proportion of crystals to glass, is responsible for many of the physical and chemical properties, such as thermal and electrical characteristics, chemical durabiUty, elastic modulus, and hardness. In many cases these properties are additive for example, a phase assemblage comprising high and low expansion crystals has a bulk thermal expansion proportional to the amounts of each of these crystals. 

Preparation and Properties of Organophosphines. AUphatic phosphines can be gases, volatile Hquids, or oils. Aromatic phosphines frequentiy are crystalline, although many are oils. Some physical properties are Hsted in Table 14. The most characteristic chemical properties of phosphines include their susceptabiUty to oxidation and their nucleophilicity. The most common derivatives of the phosphines include halophosphines, phosphine oxides, metal complexes of phosphines, and phosphonium salts. Phosphines are also raw materials in the preparation of derivatives, ie, derivatives of the isomers phosphinic acid, HP(OH)2, and phosphonous acid, H2P(=0)0H. 

Additional Selection Factors. System characteristics and physical and chemical properties can be principal considerations in reactor... 

On the macroscopic scale, two coal classifications have been used humic or banded coals and sapropeflc or nonbanded coals. Stratification in the banded coals, which result from plant parts, is quite obvious the nonbanded coals, which derive from algal materials and spores, are much more uniform. The physical and chemical properties of the different layers in a piece of coal or a seam can vary significantly. Therefore the relative amounts of the layers are important in determining the overall characteristics of the mined product. Coal petrography has been widely appHed in cokemaking and is important in coal hquefaction programs. 

Alumina is used because it is relatively inert and provides the high surface area needed to efftciendy disperse the expensive active catalytic components. However, no one alumina phase possesses the thermal, physical, and chemical properties ideal for the perfect activated coating layer. A great deal of research has been carried out in search of modifications that can make one or more of the alumina crystalline phases more suitable. Eor instance, components such as ceria, baria, lanthana, or 2irconia are added to enhance the thermal characteristics of the alumina. Eigure 6 shows the thermal performance of an alumina-activated coating material. 

Contaminant characteristics (e.g., physical and chemical properties, concentration, particrrlate shape and size distribrrtion [in the case of particrrlates], chemical reactivity, corrosivity, abrasiveness, and toxicity)... 

Engineering factors include (a) contaminant characteristics such as physical and chemical properties - concentration, particulate shape, size distribution, chemical reactivity, corrosivity, abrasiveness, and toxicity (b) gas stream characteristics such as volume flow rate, dust loading, temperature, pressure, humidity, composition, viscosity, density, reactivity, combustibility, corrosivity, and toxicity and (c) design and performance characteristics of the control system such as pressure drop, reliability, dependability, compliance with utility and maintenance requirements, and temperature limitations, as well as size, weight, and fractional efficiency curves for particulates and mass transfer or contaminant destruction capability for gases or vapors. 

Observable Characteristics - Physical State (as normally shipped) Liquid Color Colorless to slight yellow Odor Extremely sharp - lachrymator piercing and disagreeable extremely Physical and Chemical Properties - Physical State at 15 °C and 1 atm. Liquid Molecular Weight 56.1 Boiling Point at 1 atm. 127, 53, 326 Freezing Point -125, -87, 186 Critical Temperature 489, 254, 527 Critical Pressure 737, 50.0, 5.08 Specific Gravity 0.843 at 20 °C (liquid) Vcq>or (Gas) Density 1.94 Ratio of Specific Heats of Vapor (Gas) 1.1487 Latent Heat of Vaporization 216, 120, 5.02 Heat of Combustion -12500, -6950, -290 Heat of Decomposition Not pertinent. 

Observable Characteristics -Slfatc (as normally shipped) Solid Color White Odor None. Physical and Chemical Properties - Physical State at IS T7 and I atm. Solid Molecular Weight 142.11 Boiling Point at I atm. Not pertinent (decomposes at 70°C) Freezing Point Not pertinent (decomposes at 70°C) Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.50 at 18.5°C (solid) Vapor (Gas) Density Not pertinent Ratio of Specific Heats afVqtor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Data not available Heat of Decomposition Not pertinent. 

Chemical Designations - Synonyms No common synonyms Chemical Formula Ba(N03)2. Observable Characteristics - Physical State (as normally shipped) Solid Color White Odor. None. Physical and Chemical Properties - Physical State at 15 XIand 1 atm. Solid Molecular Weight ... 

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