Phenol from coal pyrolysis products

Sources of Raw Materials. Coal tar results from the pyrolysis of coal (qv) and is obtained chiefly as a by-product in the manufacture of coke for the steel industry (see Coal, carbonization). Products recovered from the fractional distillation of coal tar have been the traditional organic raw material for the dye industry. Among the most important are ben2ene (qv), toluene (qv), xylene naphthalene (qv), anthracene, acenaphthene, pyrene, pyridine (qv), carba2ole, phenol (qv), and cresol (see also Alkylphenols Anthraquinone Xylenes and ethylbenzenes). 

Lignin-derived compounds have been observed in pyrolysis products of low rank coals and associate woody tissue FI- 61. Mycke and Michaelis [2] isolated lignin-derived methoxyphenols from a Miocene coal by catalytic hydrogenolysis. Sigleo [S] reported the presence of phenolic compounds derived from iteration of lignin in pyrolysis products of silicified woody tissue as old as Triassic age. However,... 

The phenol, the cresol isomers, and the dimethylphenols, major pyrolysis products in e Moscow wood sample, are probably also derived frt>m lignin precursors that have been altered through coalification reactions. Hatcher [fr] have shown that an increase is observed in the relative proportion of phenols and cresols as rank of coaHfred wood samples increases to subbituminous coal. Comparing the distribution of pyrolysis products from the Moscow wood to that of other coalified wood samples of Hatcher allows us to deduce that the... 

A whole family of polymers is derived from formaldehyde polyacetal (polymethylene oxide), phenol-formaldehyde, urea-formaldehyde and melamine-formaldehyde. It is interesting to note that the other components (phenol, urea and melamine) are also products of coal pyrolysis. 

The pyrolysis and combustion products from RTEmp fluid were given in Tables 8 and 9, respectively. The highest-yield pyrolysis products were cyclopentadiene, benzene, and toluene, while the highest-yield combustion products were benzene, phenol, and acetic acid. While these types of products are moderately toxic, they are by no means unique to this fluid. Many of these products have been detected in this laboratory as decomposition products from maple wood. In fact, most if not all of the compounds shown in Tables 8 and 9 have been detected from a variety of combustion sources, such as coal combustion, waste incinerationj coal/refuse combustion, and automobile and truck engine exhaust ... 

Because the coal is brought rapidly to reaction temperature and the pyrolysis products are exposed to the full temperature, the Winkler reactor produces no tars or phenols, and very little methane. A typical gas composition from bituminous coal is (dry and sulfur-free) ... 

Carbon molecular sieves, or carbogoric sieves are amorphous materials made by pyrolyz-ing coal, coconut shells, pitch, phenol-formaldehyde resin, or other polymers. EKslocations of aromatic microdomains in a glassy matrix give their porosity. Pores are slit-shaped. Pore structure is controlled by the temperature of the pyrolysis. Pore widths range from 3 A to 10 A. Acarbogenic sieve made from polyfurfuryl alcohol and combined with silica-alumina was selective for monomethylamine production from methanol and ammonia [54]. 

The properties of manufactured graphites are determined by the microstructure of the carbonaceous mesophase which is formed during pyrolysis, usually between the temperatures of 370 C and 500°C. The characteristics of the final product can be measured in a qualitative way by examination of the mesophase micro-structure. Several coal liquid asphaltene and petroleum pitch samples have been screened in this way to determine their suitability as precursors for graphite materials. The physical and chemical properties of the mesophase formed from the samples and their pyrolyses residues were studied(1). It was found that the phenolic oxygen present either in the precursor or by addition during heat treatment suppresses mesophase formation by crosslinking and preventing the development of fluidity(2J>... 

Carbon fibers can be produced from a wide variety of precursors in the range from natural materials to various thermoplastic and thermosetting precursors Materials, such as Polyacrylonitrile (PAN), mesophase pitch, petroleum, coal pitches, phenolic resins, polyvinylidene chloride (PVDC), rayon (viscose), etc. [42-43], About 90% of world s total carbon fiber productions are polyacrylonitrile (PAN)-based. To make carbon fibers from PAN precursor, PAN-based fibers are generally subjected to four pyrolysis processes, namely oxidation stabilization, carbonization and graphitiza-tion or activation they will be explained in following sections later [43]. 

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