Insoluble Constituents

The high-molecular-weight constituents of coal are much more difficult to define than the low-molecular-weight constituents insofar as they (1) are difficult, if not impossible, to extract with solvents and (2) cannot be distilled, either individually or as various compound classes, from coal without the onset of thermal decomposition to low-molecular-weight fragments or, as is often the case, to a carbonaceous residue (Davidson, 1980). 

As a result of these studies, it has been possible to derive data that contribute to the knowledge of the higher-molecular-weight constituents of coal but the methods are often criticized because of the repeated attanpts by investigators to treat the data too literally and, thus, define coal in terms of a molecular structure. This, of course, leaves the whole area represented by these investigations open to extranely severe criticism and debate as to the usefulness of the exercise. 

Nevertheless, such investigations must not be wholly rejected and discredited and are actually praiseworthy insofar as they provide valuable information about the structural types present in coal. But the danger lies in attempting to present the data in terms of an average structure. 

As a side note, throughout this chapter, the term structure of coal will be employed to indicate the structure of the higher-molecular-weight species, in fact the macromolecular part, of coal to the exclusion of those lower-molecular-weight materials that can be extracted according to the methods outlined in the preceding section. 

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Graphitic Corrosion Graphitic corrosion usually involves gray cast iron in which metalhc iron is converted into corrosion products, leaving a residue of intact graphite mixed with iron-corrosion products and other insoluble constituents of cast iron. 

Scaling—the formation of thick corrosion products as layers on a metal surface in piping systems it is usually the deposition of water-insoluble constituents on a metal surface. 

Microbial insecticides are very complex materials in their final formulation, because they are produced by fermentation of a variety of natural products. For growth, the bacteria must be provided with a source of carbon, nitrogen, and mineral salts. Sufficient nutrient is provided to take the strain of choice through its life cycle to complete sporulation with concomitant parasporal body formation. Certain crystalliferous bacilli require sources of preformed vitamins and/or amino acids for growth. Media for growing these bacilli may vary from completely soluble, defined formulations, usable for bench scale work, to rich media containing insoluble constituents for production situations (10,27). Complex natural materials such as cottonseed, soybean, and fish meal are commonly used. In fact, one such commercial production method (25) is based on use of a semisolid medium, a bran, which becomes part of the final product. 

Liquid water, including its soluble and insoluble constituents, is transferred from the oceans to the atmosphere when air bubbles in the water rise to the surface. These bubbles form from air trapped by breaking waves, "whitecaps." As the bubbles burst at the surface, water droplets are injected into the atmosphere. These water droplets are small enough to remain airborne for several hours. Whitecaps begin to form in winds common over the oceans, and a significant amount of seasalt made airborne in this way is transported to the continents and deposited in coastal areas. 

We recognize today a remarkable measure of truth in these early interpretations. Across the channel, however, Weber vigorously denounced the view that the insoluble constituent is in any way related to vulcanization, saying, in part The extent to which the fact of the existence of an insoluble constituent in India rubber has inspired the imagination of our French colleagues is truly astonishing. ... 

Vacuoles. Vacuoles have been identified in young bacteria. They are cavities in the protoplasm and contain a fluid known as cell sap. As the cells approach maturity, some of the water-soluble reserve food materials manufactured by the cell dissolve in the vacuoles. Insoluble constituents precipitate out as cytoplasmic inclusion bodies. 

In the following example, a solid consisting of a soluble constituent A and an insoluble constituent B is considered. Leaching is carried out with a pure solvent S and a solution is produced containing a mass a of A, per unit mass of S and the total mass of A in solution is P. It will be assumed that the quantity of solvent removed in the underflow from each of the thickeners is the same, and that this is independent of the concentration of the solution in that thickener. It will be assumed that unit mass of the insoluble material B removes a mass s of solvent S in association with it. Perfect mixing in each thickener will be assumed and any adsorption of solute on the surface of the insoluble solid will be neglected. In a given thickener, therefore, the ratio of solute to solvent will be the same in the underflow as in the overflow. 

Thus, one test (ASTM D893) covers the determination of pentane- and toluene-insoluble constituents in used lubricating oils using pentane dilution and centrifugation as the method of separation. The other test (ASTM D4055) uses pentane dilution followed by membrane filtration to remove insoluble constituents larger than 0.8 p,m. 

In procedure A, a sample is mixed with pentane and centrifuged, after which the resid or asphalt solution is decanted and the precipitate is washed twice with pentane, dried, and weighed. For toluene-insoluble constituents, a separate sample of the resid or asphalt is mixed with pentane and centrifuged. The precipitate is washed twice with pentane, once with toluene-alcohol solution, and once with toluene. The insoluble material is then dried and weighed. In procedure B, procedure A is followed except that instead of pentane, a pentane-coagulant solution is used. 

Figure 4. Foam properties and content of insoluble constituents related to pH and percentage of glandless cottonseed flour in aqueous suspensions...

The purification of tetryl aims at removing by-products such as tetranitro derivative (VII), substances insoluble in benzene and the spent acid occluded by the crystals. The product is washed with cold water and then treated with hot water. This brings about the conversion of compound (VII) to (VIII)—the latter is soluble in hot water. The tetryl is then dissolved in benzene and insoluble constituents removed by filtration. The resulting solution is washed with water until it is completely free from acid. Alternatively, tetryl may be dissolved in acetone, precipitated with water, and finally deacidified. 

In the first instance, the roots of planta may take up all substances in solution without selection. But this action is not one of simple imbibition as in the case of sponges. Liebig-, in a recent memoir, maintains that the spongioles, in obtaining their supply of saline matter, exert a real decomposing action on certain Ill-defined compounds, which the saline mattar forms with the. insoluble constituents of the soil, Those substances which are conveyed to planta in solution are retained in greater or less quantity, or are entirely rejected when not fit For assimilation. 

In the shape of agricultural produce of a field, the entire amount of those constituents which have become ingredients of plants is removed from the soil. After a series of years, and a corresponding number of harvests, the fertility of the soil or field diminishes. The change which is found to have taken place in the composition of the soil after harvest, is the probable cause of its diminished or lost fertility. By means of solid and liquid manure, or the excreta of men and animals, the loBt or diminished fertility of the land is restored. Solid or farmyard manure consists of decayed vegetal and animal matters, which contain a certain proportion of the constituents of the soil. The excrements of men and animals represent the ashes of the food consumed, and which has been derived from the supposed soil. The urine contains the soluble, the solid excrete the insoluble constituents of the soil derived from the crops used as food, and reaped from the soil. By adding these to the soil, it recovers those constituents which have been removed from it in the crops. 

Another method, not specifically described as an asphaltene separation method, is designed to remove pentane- or heptane-insoluble constituents by membrane filtration (ASTM D-4055). In the method, a sample of oil is mixed with pentane in a volumetric flask, and the oil solution is filtered through a 0.8-p.m membrane filter. The flask, funnel, and filter are washed with pentane to completely transfer any particulate matter onto the filter, after which the filter (with the particulate matter) is dried and weighed to give the pentane-insoluble constituents as a percent by weight of the sample. Particulate matter in the extracts can also be determined by membrane filtration (ASTM D-2276 ASTM D-5452 ASTM D-6217 IP 415). 

The ceramic approach which appears the best to date because of versatility of composition as well as fire-retardancy is illustrated by the formulation which follows. In future modifications of the recipe, the sodium silicate will be replaced by an insoluble constituent, such as a silicone. 

N aqueous ammonia are added to the mixture. The insoluble constituents are filtered off and washed ion-free with diethyl ether and water. The filter cake is dried and there is obtained l-(p-methoxybenzoyl)-2-pyrrolidinone having a melting point of 119.5°-120.5°C. 

Let us consider vapor-liquid (or vapor-solid) equilibria for binary mixtures. For the sake of simplicity it will be assumed that all gases are ideal. In addition to the vapors of each component of the condensed phase, the gas will be assumed to contain a completely insoluble constituent, the partial pressure p of which may be adjusted so that the total pressure of the system, p, assumes a prescribed value. Therefore, C = 3, P = 2, and, according to equation (51), F = 3. Let us study the dependence of the equilibrium vapor pressures of the two soluble species p and P2 on their respective mass fractions in the condensed phase X and X2 at constant temperature and at constant total pressure. Since it is thus agreed that T and p are fixed, only one remaining variable [say X ( = l — "2)] is at our disposal p, P2 and the total vapor pressure p = p + p2 will depend only on X. ... 

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