Pitch solubility

Examples of polymers which form anisotropic polymer melts iaclude petroleum pitches, polyesters, polyethers, polyphosphaziaes, a-poly- -xyljlene, and polysdoxanes. Synthesis goals iaclude the iacorporation of a Hquid crystal-like entity iato the maia chaia of the polymer to iacrease the strength and thermal stabiHty of the materials that are formed from the Hquid crystal precursor, the locking ia of Hquid crystalline properties of the fluid iato the soHd phase, and the production of extended chain polymers that are soluble ia organic solvents rather than sulfuric acid. 

The resin is fairly soluble in aleohol, ether and chloroform and is decomposed by nitric acid. It becomes thermoplastic at temperatures above 150°C and decomposes at a temperature rather below 300°C, yielding an oil of amber and leaving a residue known as amber colophony or amber pitch. 

Coal-tar pitches generally soften around 110°C, are about 70 wl% soluble in toluene and 12 wt% insoluble m quinoline. Excessive amounts of primary qumohne insolubles (QI) would contribute to increased carbon yield, but such a pitch may not wet coke well and could hinder the penetration of pitch into the coke voids. 

Table 4 summarizes the yield of soluble pitch for the hydrogenation experiments. Hydrogenation of WVGS 13407 at 350°C increased the pilch yield from about 66 to 84 wt% Although the incremental yield between untreated and hydrogenated coal is only 18 wt%, there were significant differences m the properties of the pitches in terms of their carbonization behavior. 

Hydi ogenation of WVGS 13421 at 350°C, on the other hand, increased the pitch yield from about 35 wt% for the untreated coal to 62 wt%. Hydrogenations at 400 and 450°C produced more than double the quantity of soluble material over that of the unhydrogenated coal. Although the yield of products obtained at 400... 

Elemental analysis was performed on various coals, pitches, and blends. Table 7 reports the elemental composition of products from WVGS 13407. Compared to the raw coal, the NMP-soluble extract (EXT) contams essentially the same amount of carbon, though there is slightly more hydrogen as mdicated by a... 

Only a limited number of coal-denved pitches were examined by H NMR because of their low solubility in solvents commonly used m conventional proton magnetic resonance. Table 12 reports the distribution of hydrogen for three of the pitches. Unlike coal-tar pitches, which typically have over 85% of the hydrogen bonded to aromatic carbon, the matenals listed in Table 12 are characterized by a high content of aliphatic hydrogen. 

Table 11. Charactenstics of NMP-soluble pitches from WVGS 13421...

Coal tar pitch volatiles measurement of particulates and cyclohexane soluble material in air Lab method using filters and gravimetric analysis 68... 

Coal tar pitch volatiles, see Particulate polycyclic aromatic hydrocarbons (PPAH), as benzene solubles Cobalt metal, dust and fume (as Co)... 

Mutant YE-2 of Rhizobium meliloti excretes a mixture of soluble polysaccharides that include a complex succinoglycan having a branched octasaccharide repeat as well as a simple galactoglucan (22) having a linear disaccharide repeat.102 In contrast to the case of the succinoglycan, oriented fibers of the potassium salt of 22 have yielded good X-ray data and its three-dimensional structure has been established.39 The polymer forms a two-fold helix of pitch... 

C A pitch insoluble in benzene but soluble in benzene/ ethanol azeotrope 40 Consists almost entirely of aromatic fragments attached to phenol by methylene bridges. These fragments are larger than in fraction B as they contain polyaromatic groups. It has more oxygen functional groups than B. 

Figure 1. Liquefaction yields vs. maximum fluidities in the fused state of coal (%), solvent (SRC pitch benzene soluble) (O), pyrene ((B), no solvent. Coal.sol-vent ratio = 1 3 reaction temperature = 390°C(8).

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