Alternatives to Phenols

Abundant byproducts of the Coalite process were also low temperature tars, containing cresylic acids (cresols the products were referred to as meta cresol and cresylic acid). With the sudden increase in the price of phenol around 1937, and further rises in 1938, both as a result of demand from the plastics industry (despite a general downturn in trade), it was suggested that Low Temperature Carbonisation Ltd. investigate catalysts suited to condensations of cresylic acids (as an alternative to phenol) with formaldehyde. Certainly there was a greater dependence in Britain on cresylics than was the case in the United States, because of their availability from coal-based processes. In the meantime Monsanto, which manufactured coal tar cresols (as did Yorkshire Tar Distillers), was considering the erection of a second British synthetic phenol plant. 

Hydrocarbon resins from petroleum are commonly used as a less expensive alternative to phenolic tackifying resins. These resins are commonly used in the tire industry however, they do not impart aged tack as good as phenolic tackifier resins. 

Hydrocarbon tackifiers are used as a less expensive but lower performing alternative to phenolic tackifiers. 

This reaction, applicable only to the preparation of hydroxy-aldehydee, is alternative to the Gattermann aldehyde reaction (or the Adams modification of it) given under 4. The yields are usually smaller, but a large quantity of the phenol may be recovered. The following mechanism is consistent with the known facts ... 

In the 1960—1980 period, the use of more economical synthetic isopropyl- and /-butylphenols as alternatives to cresols was developed (98,99). Commercial triaryl phosphates such as FMC s Kronitex 100 and Ak2o s Phosflex 31P and 41B are based on partially isopropylated or /-butylated phenol. The relative volatihties and oxidative stabiUties of these phosphates have been compared the /-butylphenyl phosphates are the most oxidatively stable of the alkylphenyl phosphates (100). 

A popular alternative to the step utili2ing chromogen is to substitute -hydroxyben2enesulfonate for phenol in the reaction with the pyridine nucleotide ... 

Aqueous dispersions are alternatives to solutions of Hquid and soHd resins. They are usuaUy offered in 50% soHds and may contain thickeners and cosolvents as stabilizers and to promote coalescence. Both heat-reactive (resole) and nonheat-reactive (novolak) systems exist that contain unsubstituted or substituted phenols or mixtures. A related technology produces large, stable particles that can be isolated as discrete particles (44). In aqueous dispersion, the resin stmcture is designed to produce a hydrophobic polymer, which is stabilized in water by an interfacial agent. 

Vinyl acetate-ethyl acetate Close-hoihng Phenol, aromatics Alternative to simple distillation... 

Me3SiCHN2, MeOH, benzene, 20°. This reagent does not react with phenols This is a safe alternative to the use of diazomethane. A detailed, large-scale preparation of this useful reagent has been described. ... 

An alternative to cyclohexanones from phenols involves ring saturation to the alcohol, followed by oxidation 14). 

Photoaddhion of electron donor olefins such as vinyl ethers and stilbene to variously methyl and halogeno-substituted 1,4-benzoquinones resulted in the formation of dihydrobenzofurans via a dienone-phenol rearrangement of the primary product spirooxetanes <96H(43)619>. High-temperature water seems to be an alternative to use of acid catalysts or organic solvents by the cyclization of allyl phenyl ethers to dihydrobenzofurans <96JOC7355>. 

This phenol synthesis complements the analogous reaction (see below) from arylthallium ditrifluoroacetates (147). Although yields are only moderate, the procedure represents a viable conversion of aryl Grignard reagents to phenols. It is a practical method, however, only when the diarylthallium trifluoroacetate precursor is formed via the Grignard route the alternative synthesis via symmetrization of arylthallium ditrifluoroacetates is obviously circuitous, since the latter compounds may be converted directly to phenols. 

As an alternative, successive monooxygenation of benzene to phenol, catechol, and 1,2,3-trihydroxybenzene may be accomplished by the toluene 4-monooxygenase of Pseudomonas mendocina strain JKRl and the 3-monooxygenase of Ralstonia Pseudomonas) pickettii strain PKOl (Taoetal. 2004). 

Hydroxylamines Reducing phenolic discoloration alternative to traditional phenolic AO based stabilisation... 

There are several chemical compounds found in the waste waters of a wide variety of industries that must be removed because of the danger they represent to human health. Among the major classes of contaminants, several aromatic molecules, including phenols and aromatic amines, have been reported. Enzymatic treatment has been proposed by many researchers as an alternative to conventional methods. In this respect, PX has the ability to coprecipitate certain difficult-to-remove contaminants by inducing the formation of mixed polymers that behave similarly to the polymeric products of easily removable contaminants. Thus, several types of PX, including HRP C, LiP, and a number of other PXs from different sources, have been used for treatment of aqueous aromatic contaminants and decolorization of dyes. Thus, LiP was shown to mineralize a variety of recalcitrant aromatic compounds and to oxidize a number of polycyclic aromatic and phenolic compounds. Furthermore, MnP and a microbial PX from Coprinus macrorhizus have also been observed to catalyze the oxidation of several monoaromatic phenols and aromatic dyes (Hamid and Khalil-ur-Rehman 2009). 

Triaryl esters can be prepared by a variety of methods. For example, by allowing 3 mol. of the phenol to react with 1 mol. of phosphorus oxychloride for several hours. Organic bases such as aniline, dimethylaniline and pyridine have been used to neutralize the hydrogen chloride formed in the reaction.3 Alternatively, the phenols may be converted into the sodium phenoxides4 and then allowed to react with phosphorus oxychloride. 

An alternative route to phenolate-like EGBs is through the cathodic reduction of quinonemethides, (36), [82, 83]. The advantage of these PBs is that they are reduced at modest potentials, which allow EGB formation to take place in situ, and they are ultimately converted into phenols that are easily reoxidized to (36) either by air or by anodic oxidation (60-70% yield) [82]. The radical anion (36a) is expected to have basicity similar to that of (35) , whereas the pK of the conjugate acid of the dianion formed by further reduction can be assumed close to that of triphenylmethane, 30.6. 

Activity Measurements in Solution. The 2 -chloro, 4 -nitrophenyl / -D-glycosides offer an attractive alternative to classical reductometric methods. The substrate is sufficiently stable (pH 5.5, 50°C) and the favorable absorption characteristics of the liberated phenol (pK = 5.5, a/9000 M 1cm 1, pH 5.5 cm 16000 at pH 6.5) allow sensitive, continuous measurements. Kinetic parameters for some of these substrates and enzymes were determined K values were in the mM range for the lactoside (CBH I, EG I, EGD) and were at least 10 times lower for the cellobioside turnover numbers ranged from 1 (CBH I, cellobioside) to 300 min-1 (EG D, cellobioside) (25°C). 

The catalytic oxidation of liquid hydrocarbons with air or oxygen. Since oxygen is not very soluble in the liquid, while the hydrocarbon could well be present in high concentration we could end up in extreme 1 (excess of B). The removal of dissolved organics from industrial waste water by catalytic oxidation as an alternative to biooxidation. Here oxygen is not very soluble in water, but the organic waste is also present in low concentration. It is therefore not clear in what regime the kinetics lie. The catalytic oxidation of phenol is an example of such an operation. 

Predicting the toxicity of oil-shale industry waste-water by its phenolic composition. ATLA (Alternatives to laboratory animals/published by Fund for the replacement of animals in medical experiments), 27, 359-366. 

Chen (29) found that the amount of sulfuric acid directly determines the hardening time in the acid condensation of spent sulfite liquors used in plywood and veneers. However, in general the adhesives based purely on acid condensed lignins have often been found to be an uneconomic and qualitatively inferior alternative to adhesives based on synthetic polymers and phenol or lignin-formaldehyde resins. 

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