8. Phenols modification by phenol formaldehyde condensation

During the process of novolak polycondensation, the phenols become insoluble in water, but phenol formaldehyde resins (PFRs) have a good solubility in organic solvents, for example, in alcohols. The first step of phenol transformation is the chemical modification of SCCP without their preliminary fractionating to synthesize FFR with the view of obtaining inhibitor having the highest activity.

Indeed, the standard novolak PFR from monoatomic phenols has demonstrated inhibiting effect of 30%, when it is tested as phenol inhibitor at 0.03% mass consumption. Novolak polycondensate, obtained from summarized coke-chemical phenols (SCCP, No. 4., Table 2), demonstrates ~67% effect at the same consumption [5]. Unmodified SCCPs show 24% effect at the consumption of 0.03% mass (Figure 2).

Figure 2. Dependency of inhibit effect on the consumption of PFR (1) and SCCP(2).

The obtained PCF preparation was introduced into EP-300 production unit of Angarsk Polymer Plant of Petrochemical Company "ROSNEFT" and was employed for 2 years up to its run-

Table 6. Effectiveness of inhibiting polymer formations for EP-300 pyrocondensates at the inhibitor consumption of

No. Inhibitors Practical yields of resins, mg/100 sm<sup>3</sup> Effect of inhibiting, %

1 Blank experiment 233 – 2 Initial overall CCP 177 24 3 PCF fraction 77.6 66.7 4 PFR on the basis of CCP 76.4 67.2 5 CCP, modified with oxidized coupling 64.8 72.2 6 5-Methyl resorcin (from resorcin fraction)—0.009% 78.8 66.2 7 Ionol 139.8 40.0 8 TBPC 75.0 67.8

314 Phenolic Compounds - Natural Sources, Importance and Applications

The problem of utilization of CCP without the stage of power cost-based phenol vacuum fractionating has been arisen. But the problem is not unequivocal: its main disadvantages, for example, good water solubility and unpleasant organoleptic properties are not removed by this way of utilization, and in addition to that, the major part of overall (summarized) phenols

7. Increase inhibiting properties of phenols by chemical modification

That is why new methods of utilization of summarized CCP (SCCP) have been elaborated to

Analysis of literary sources reveals some ways to decrease water solubility of phenols, they are

During the process of novolak polycondensation, the phenols become insoluble in water, but phenol formaldehyde resins (PFRs) have a good solubility in organic solvents, for example, in alcohols. The first step of phenol transformation is the chemical modification of SCCP without their preliminary fractionating to synthesize FFR with the view of obtaining inhibitor having

(1) Phenol formaldehyde condensation (PFC) under acid catalysis (by novolak method)

8. Phenols modification by phenol formaldehyde condensation

(more than 2/3 of total amount) is not found in any application.

avoid the stage of preliminary power cost-based fractionating.

out in the company stocks.

0.025 %.

as follows:

(2) Phenol alkylation

the highest activity.

(3) Oxidative cross-linking of phenols

It must be accentuated that PFR, synthesized from separate fractions of monoatomic phenols obtained from summarized phenols, or diatomic phenols are worse than for PFR, produced from non-fractionated phenols, where inhibiting effects are 30–35%, at the same as above consumption of 0.03% mass. This fact is the witness of synergism of the mixtures of monoatomic and diatomic phenols after their phenol formaldehyde polycondensation. The effect is found by us early [6] during inhibiting the thermo-polymerization process of styrene with ionol and TBPC inhibitors. The inhibiting factors of the resins obtained from phenols of different stock reservoirs are quite different (Table 7).


Table 7. Comparative effect of PFR produced from phenols of different stock reservoirs at the consumption of 0.03% mass.

The results of Table 7 support the considerable inhibiting effect of synthesized novolak resins that depends on the ratios of mono- and diatomic phenols in the initial mixtures. Indeed, the increase of monoatomic phenol amounts leads to the decrease in inhibiting effect, and just the reverse, it leads to increasing this effect at the increasing diatomic phenol amounts (reservoir No. 2).

However, it should be noted that inhibiting activity of synthesized PFR from SCCP is fundamentally dependent on molecular mass (viscosity) of the resin taken.

Dependency of the inhibiting effectiveness from viscosity of PFR at the consumption of 0.03 % mass is as follows:


According to these dates, the resins having viscosity in the rage of 135 s (Viscosimeter VZ-4) are the most effective. There is dependence between amounts of residual phenols in synthetic tar-water and viscosity of the resin. For example, in the best point (74.7%) the amount of nonreacted phenols on water phase reached almost 5% of their load, and all the phenols are presented by monoatomic isomers.
