P-alkylphenol

Nickel also has been used as a dye site in polyolefin polymers, particularly fibers. When a nickel compound, eg, the stearate or bis(p-alkylphenol) monosulfide, is incorporated in the polyolefin melt which is subsequently extmded and processed as a fiber, it complexes with certain dyes upon solution treatment to yield bright fast-colored fibers which are useful in carpeting and other appHcations (189). Nickel stearate complexing of disperse mordant dyes has been studied (190). 

The enzyme p-ethylphenol methylene hydroxylase (EPMH), which is very similar to PCMH, can also be obtained from a special Pseudomonas putida strain. This enzyme catalyzes the oxidation of p-alkylphenols with alkyl chains from C2 to C8 to the optically active p-hydroxybenzylic alcohols. We used this enzyme in the same way as PCMH for continuous electroenzymatie oxidation of p-ethylphenol in the electrochemical enzyme membrane reactor with PEG-ferrocene 3 (MW 20 000) as high molecular weight water soluble mediator. During a five day experiment using a 16 mM concentration of p-ethylphenol, we obtained a turnover of the starting material of more than 90% to yield the (f )-l-(4 -hydroxyphenyl)ethanol with 93% optical purity and 99% enantiomeric excess (glc at a j -CD-phase) (Figure 14). The (S)-enantiomer was obtained by electroenzymatie oxidation using PCMH as production enzyme. 

The less strained 15-membered ring bases (mucronine-A, -B, -C) provide a characteristic maximum, resulting from the styrylamine portion, at 273 nm similar to the N-styrylamides. The dihydro derivatives show maxima at 227, 276, and 283 nm, typical of p-alkylphenol ethers. 

A number of investigations on the synergistic effect of a second extractant, such as amines and oximes, on the extraction of metal carboxylates have been carried out. The utilized synergists include 8-hydroxyquinoline-2-aldoxime for Zr(IV) and Hf(IV) (122,123), various amines (25), Lix 63 (27) and nonylphenol (28) for Cu(II), dialkylphos-phoric acids for Hf(IV) (44), rhodamine B for Be(IE) (102), trioctylphos-phine oxide for U(VI) (69, 77), p-alkylphenol for Cs(I) (1), collidine for Zr(IV) and Sc(IEI) (62), and nonchelating oximes for Ni(II) and Co(II) (103). Mareva et al. (77) have successfully utilized a salicylic acid-trioctylphosphine oxide mixture for the separation of uranium from rare earths, thorium, zirconium, and iron. 

The enzymatic polymerization proceeded even in a biphasic system consisting of two mutually immiscible phases (isooctane and water).23 In the polymerization of p-alkylphenols in this system, the molecular weight increased as a function of the carbon number of the alkyl group. 

Various other p-alkylphenols have been studied in one-pot procedures. However, the yields of calixarenes are generally lower than with 1, and individual compounds often can be isolated only by chromatography. Table 1 gives a survey. As a rule of thumb it may be concluded that calixarene formation is favoured for those alkylphenols, where a tertiary carbon is attached to the p-position. Calixarenes p-substituted by electron-withdrawing residues have not been obtained by one-pot syntheses starting with the single phenol, while p-benzyloxy- and p-phenylphenol were used with some success. 

A prototype of this procedure was first published in 1941 by Zinke and Ziegler, although the unambiguous identity of the product was not established until some years later. A few other p-alkylcalix[4]arenes have been prepared by this procedure, but for practical purposes it appears to be restricted to p-alkylphenols in which the p-alkyl group is highly branched at the position adjacent to the phenyl ring. Thus, p-tert-pentylcalix[4]arene and p-(l,l,3,3-tetramethylbutyl)calix[4]arene are among the few other phenols that yield a tractable product in reasonable yield. 

Flo. 2. Correlation of cracking of p-alkylphenols over aluminum fluoroborate-alumina catalyst at 400° (2S) by the Taft equation. 

Alkyl-p-benzoguiaones. Oxidation of p-alkylphenols (1) with this salt in the presence of perchloric acid results in 2-alkyl-l,4-benzoquinones (2) in 65-70% yield (three examples). ... 

Since 1950 100 ppm Ethylene oxide/propylene oxide copolymers, p-alkylphenol formaldehyde resins with ethylene/propylene oxides modifications... 

Since 1976 10 to 30 ppm Oxalkylated, cyclic p-alkylphenol formaldehyde resins, and complex modifications... 

Resins based on para-substituted phenols can be either one-step or two-step, but they cannot cure to a thermoset state. In the manufacture of phenolic resins, smaller quantities of acetaldehyde and furfuraldehyde are used in addition to formaldehyde. Furthermore, resorcinol, bisphenol A, and p-alkylphenols are employed, in addition to phenol, when special properties are desired. Formaldehyde concentrations of 37-50 weight % in aqueous solutions are most commonly employed. The catalysts most frequently used are acids such as oxalic, hydrochloric, sulfuric, p-toluenesul-fonic, and phosphoric and bases such as sodium, calcium, and barium hydroxide. In the weakly acidic range metal carboxylates are employed. Thermoset phenolic resins are employed as structural adhesives for laminating and bonding applications. Para-alkyl-substituted resins are employed as tackifiers in contact adhesives, pressure-sensitive adhesives, and hot-melt adhesives. 

Using heat-reactive p-alkylphenolic resins or ortho-ortho resole resins in aromatic solvent and a polymeric isocyanate in the presence of a small amount of tertiary amine, a rapidly curing adhesive system of good overlap shear for both wood and aluminum can be obtained. The best metal and wood adhesive is based on p-cresol or a straight phenolic ortho-ortho resole in combination with a polymeric aromatic isocyanate such as PAPI or Mondur MRS." ... 

Further reduction of the hydroxyketones leads to the formation of o- or p-alkylphenols, respectively. 

The reaction is conducted in a solvent glacial acetic acid, heptane, etc.). saturated with dry hydrogen chloride. The initial mesitylene diols are produced by the reaction of p-alkylphenols with two moles of formaldehyde in the presence of alkaline agents [NaOH, Na2C03, Ca(OH)2,etc.], which serve as catalysts of the reaction [205-212]. 

Phenolic-modified alkyds are made by heating the alkyd with a low molecular weight resole phenolic resin based on p-alkylphenols. Presumably, the methylol groups on the phenols react with some of the imsatmated groups of the alkyd to form chroman structures. The resins give harder films with improved water and chemical resistance as compared to the immodified alkyd. 

On this basis, calix[4]arene 1, thiacalix[4]arene 2, cahx[4]resorcinarene 3, and calix[4]pirogallolarene 4 (Scheme 4.1), which are cyclocondensation products of p-alkylphenols with formaldehyde or sulfur in alkaline medium and of acid-catalyzed reaction of resorcinol or pyrogallol with aldehydes, are used as basic blocks for the construction of host molecules. 

The simplest p-alkylphenol is p-cresol (35), which has a methyl substituent. One of the first detailed studies of the HRP-catalyzed oxidation of p-cresol was reported in 1976 [51]. Recently, a detailed in situ NMR analysis revealed details of the coupling mechanism of the p-cresol polymerization. NMR and H- H gCOSY 2D NMR analysis suggested that ortho-ortho coupling (43) is the dominant coupling mechanism at the initial stage of the polymerization. The consumption of dimer accelerated only after the complete conversion of the monomer in the reaction mixture. After a reaction time of about 75 min, the formation of Pummerer s ketone (44) was observed. These ketonic species are formed from ortho-para-coupled dimers by intramolecular Michael addition. They are probably not able to participate in the further polymerization process and remain as side products (Scheme 9) [76]. Experiments with 4-propylphenol have revealed that the formation of Pummerer s ketone may be suppressed at lower temperatures [112]. 

With the use of tin chloride, p-alkylphenol is used to make phenol disulfide accelerator. 

Alkylphenol Oxidation. 1,4-Quinone methides can be obtained by the reaction of p-alkylphenols with Ag20. These reactive compounds may undergo subsequent transformations, for example, a Lewis acid promoted cyclization (eq 5). 1,2-Quinone methides can also be formed by Ag20 oxidation of appropriately substituted phenols eqs 6 and 7). ... 

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