5. Coke-chemical phenols

During thermal processing of coals, the main components of coke-chemical phenol (CCP) mixtures are different mono- and diatomic phenols, where compositions are dependent on coalfield (Table 2).

Table 2 demonstrates the essential differentiations in mono- and diatomic phenol proportions in different storage reservoirs. These proportions play very important role to produce effective inhibitors from CCP. It is experimentally established that the optimal proportion is <2:1.

As an example, the composition of phenols from storage reservoir No. 2 is given in Table 3.

According to Table 3, diatomic phenols are predominantly presented with pyrocatechine and his gemologists, as well as with insignificant amount of resorcin and its derivatives and with minor amount of methyl and dimethyl hydroquinone.

That is why the first alternative to increase the inhibiting activity of CCP is the fractionating of the phenol mixture for the purpose of isolating diatomic phenols from monoatomic ones. During fractionating, the distillate of diatomic phenols, the so-called "pyrocatechine fraction"


Table 2. Comparative composition of CCP from different storage reservoirs.

It is found that guaiacol and syringol derivatives in non-polar media do not reveal their inhibiting activities, so the hydrogen atom of phenol hydroxyl group forms the hydrogen binding with oxygen atom of neighboring (in ortho-position) methoxyl group, which prevents

Component Component composition, %

Phenol 3.5 Crezols 13.9 Xylenols 15.4 Guaiacol 7.1 4-Methylguaiacol 5.3 4-Ethylguaiacol 4.2 4-Propylguaiacol 2.1 Eugenol 1.4 Pyrocatechine 5.7 Methylpyrocatechine 1.6 1,3-Dimethyl ether of 5-methylpyrogallol 12.7 1,3-Dimethyl ether of 5-ethylpyrogallol 10.3 1,3-Dimethyl ether of 5-propylpyrogallol 6.5

310 Phenolic Compounds - Natural Sources, Importance and Applications

During thermal processing of coals, the main components of coke-chemical phenol (CCP) mixtures are different mono- and diatomic phenols, where compositions are dependent on

Table 2 demonstrates the essential differentiations in mono- and diatomic phenol proportions in different storage reservoirs. These proportions play very important role to produce effective inhibitors from CCP. It is experimentally established that the optimal proportion is

the phenoxyl radical formation:

Table 1. Composition of phenols for pyrolysis of wood.

5. Coke-chemical phenols

coalfield (Table 2).

<2:1.


Table 3. Component composition of phenol mixture in storage reservoir No. 2.

(PCF), has been isolated. The fraction is analyzed and tested as polymerization inhibitor of industrial condensates for EP-300 utility of Angarsk Polymer Plant (APP) of "ROSNEFT" Joint-Stock Company, Irkutsk region, Russia [4]. Inhibiting activities of PCF and other inhibitors have been tested in accordance with the standard protocol of 8489-85 RU State Standard. The industrial samples of liquid pyrolysis products (pyrocondensates) of straight-run distillation of gasoline and hydrocarbon gases have been used as investigation objects.

The estimation of their inhibiting activities has been modeled under very closed conditions, or even under more hard conditions, than that for real-system "column-boiler" at the rectification process of pyrolysis semi-products, where the example is chosen from pyrocondensate of typical utility of "Ethylene/propylene-300" of APP, where production is benzene produced by hydrodealkylation.

Laboratory experiment on modeling polymer formation has included the following:

(1) Initiation of polymer formation in pyrocondensate by temperature impact with the addition of investigated inhibitor.

For this purpose, pyrocondensate of 100 cm<sup>3</sup> was loaded into a metal autoclave, and the inhibitor was added (or not added in blank experiment); the autoclave was sealed hermetically and placed into a preliminary heated thermostat at 130°C for 1 h.

(2) The amounts of the polymer formed products were detected by RU State Standard 8489-85 by the equipment "POS-77M."

Effectiveness of inhibiting was estimated in accordance with the formula:

$$\text{Effectiveness} = \frac{\text{C}\_{\text{blank}} - \text{C}\_{\text{ribub}}}{\text{C}\_{\text{blank}}} 100\% \tag{6}$$

where Cinhib and Cblank are the amounts of experimental resins in pyrocondensates in inhibit and blank experiments, correspondingly.
