Phenols =* alkyl benzenes

D. G. Rea. Private communication. IR association of phenols, phenol-alkyl-benzenes. 

Alkylation. Benzene and phenol feedstocks are readily alkylated under Friedel-Crafts conditions to prepare extensive families of alkylated aromatics. These materials generally are intermediates in the production of surfactants or detergents such as linear alkylbenzenesulfonate (LABS) and alkylphenolethoxylate (APE). Other uses include the production of antioxidants, plasticizers, and lube additives. 

It has become clear that benzoate occupies a central position in the anaerobic degradation of both phenols and alkylated arenes such as toluene and xylenes, and that carboxylation, hydroxylation, and reductive dehydroxylation are important reactions for phenols that are discussed in Part 4 of this chapter. The simplest examples include alkylated benzenes, products from the carboxylation of napthalene and phenanthrene (Zhang and Young 1997), the decarboxylation of o-, m-, and p-phthalate under denitrifying conditions (Nozawa and Maruyama 1988), and the metabolism of phenols and anilines by carboxylation. Further illustrative examples include the following ... 

Phenol, 13 747-756, 757. See also Phenols alkylation, 2 196—197 analytical methods for, 18 753—754 antimicrobial used in cosmetics, 7 831t from benzene, 3 620 from benzoic acid oxidation, 3 631 binary azeotrope with benzaldehyde, 3 591t... 

A wide range of anionic surfactants (Fig. 23) has been classified into groups, including alkyl benzene sulfonates (ABS), linear alkyl benzene sulfonates (LAS), alcohol sulfates (AS), alcohol ether sulfates (AES), alkyl phenol ether sulfates (APES), fatty acid amide ether sulfates (FAES), alpha-olefin sulfates (AOS), paraffin sulfonates, alpha sulfonated fatty acids and esters, sulfonated fatty acids and esters, mono- and di-ester sulfosuccinates, sulfosuccinamates, petroleum sulfonates, phosphate esters, and ligno-sulfonates. Of the anionic surfactants, ABS and LAS continue to be the major products of anionic surfactants [314, 324]. Anionic surfactants have been extensively monitored and characterized in various environmental matrices [34,35,45,325-329]. 

Ethylbenzene is to styrene what cumene is to phenol. The only reason you want to make ethylbenzene is so you can malce styrene. Its destiny is tied to styrene consumption. Most ethylbenzene (EB) is made by alkylating benzene with ethylene, as shown in Figure 8—1. 

Alkyl- benzene Methyl- benzene Methyl- phenol Methyl- naphthalene aiSc... 

The number of isomers of alkylated aromatics is enormous. Lower members of alkylated benzenes such as xylenes are well resolved and detected by FID and MS. Increased alkylation causes an increase in the number of isomers. In the case of both alkylated phenols and aromatics various isomers are existing in a continuous pattern. The lower alkylation gives few well resolved isomers. The higher alkylation gives a large number of isomers but in smaller concentrations. 

The conventional resinsulfonic acids such as sulfonated polystyrenes (Dowex-50, Amberlite IR-112, and Permutit Q) are of moderate acidity with limited thermal stability. Therefore, they can be used only to catalyze alkylation of relatively reactive aromatic compounds (like phenol) with alkenes, alcohols, and alkyl halides. Nafion-H, however, has been found to be a suitable superacid catalyst in the 110-190°C temperature range to alkylate benzene with ethylene (vide infra) 16 Furthermore, various solid acid catalysts (ZSM-5, zeolite /3, MCM-22) are applied in industrial ethylbenzene technologies in the vapor phase.177... 

Other detergent alkylates which are gaining acceptance are benzene alkylated by pentamer and phenol alkylated by polypropylene, of which trimer is the preferred polymer. The pentadecylbenzene alkylate is sulfo-nated, while the nonylphenol alkylate is further reacted with ethylene oxide, the latter product going into the production of liquid non-ionic detergents. 

Cumene or isopropylbenzene, diisopropylbenzene, and secondary butyl-benzene, although produced in smaller quantities than some of the other petrochemical alkylates, are very important petroleum refining products. Cumene is further reacted by oxidation to form cumene hydroperoxide, which is converted to phenol and acetone it is produced by alkylating benzene with propylene catalyzed by either solid or liquid phosphoric acid. Secondary butylbenzene is made by alkylating benzene with normal butylene using the same catalysts. Diisopropylbenzene is made by reacting cumene with propylene over solid phosphoric acid or aluminum chloride catalyst. 

Friedel-Crafts type reactions of strongly deactivated arenes have been the subject of several recent studies indicating involvement of superelectrophilic intermediates. Numerous electrophilic aromatic substitution reactions only work with activated or electron-rich arenes, such as phenols, alkylated arenes, or aryl ethers.5 Since these reactions involve weak electrophiles, aromatic compounds such as benzene, chlorobenzene, or nitrobenzene, either do not react, or give only low yields of products. For example, electrophilic alkylthioalkylation generally works well only with phenolic substrates.6 This can be understood by considering the resonance stabilization of the involved thioalkylcarbenium ion and the delocalization of the electrophilic center (eq 4). With the use of excess Fewis acid, however, the electrophilic reactivity of the alkylthiocarbenium ion can be... 

There was a much larger variation between pyrolysis products volatile fractions for the exinites and vitrinites. The sporinite yielded mostly normal alkanes and alkenes up to approximately C19 with C16 being the most abundant product. The very low molecular weight hydrocarbons such as methane and ethane were not analyzed. Also, benzene and phenol derivatives were found as minor products. The vitrinite products were dominated by aromatics such as alkyl benzenes, alkylnaphthalenes, phenols, and naphthols. The smaller alkane/alkenes were also found. These results are most consistent with what was found in pyrolysis MS of sporinites and vitrinites (5,7). 

Allylphenols and derivatives with substituents in the allyl group can, be prepared by direct C-alkylation of the sodium salt of the phenol in benzene solution.16 This method is not as good for the preparation of allylphenols themselves as the one involving preparation of the allyl ether followed by rearrangement, because a mixture of several products is obtained in C-alkylation. Thus the alkylation of p-cresol in benzene with sodium and allyl bromide yields 20% of allyl 4-methylphenyl ether, 8% of allyl 2-allyl-4-methylphenyl ether, 40% of 2-allyl-4-methyl-phenol, and 15% of 2,6-diallyl-4-methylphenol.16 The rearrangement of allyl 4-methylphenyl ether, however, yields 2-allyl-4-methylphenol in practically quantitative yield, and the ether is easily obtained. 

The extent of C-alkylation as a side reaction in etherification varies about 1% of allyl 2-allylphenyl ether is formed when phenol is used in the acetone and potassium carbonate method with allyl bromide with cinnamyl bromide or 7,7-dimethylallyl bromide the extent of C-alkylar tion is greater.16 A complicated mixture of C- and O-alkylation products results from the treatment of phenol with 4-bromo-2-hexene and 4-chloro-2-hexene. 9 4-Hexenylresordnol has been obtained in about 40% yield from the reaction of l-bromo-2-hexene, resorcinol, and potassium carbonate in boiling acetone.99 An appreciable amount of C-alkylation occurs when 2,6-dimethyIphenol is treated with allyl bromide and sodium ethoxide in ethanol.70 Since, in general, the ampunt of C-alkylation is greatly increased by carrying out the alkylation on the sodium salt of the phenol in benzene,16 this method is unsuitable for the preparar tion of allyl aryl ethers. 

Although significant improvements have been made in the synthesis of phenol from benzene, the practical utility of direct radical hydroxylation of substituted arenes remains very low. A mixture of ortho-, meta- and para-substituted phenols is typically formed. Alkyl substituents are subject to radical H-atom abstraction, giving benzyl alcohol, benzaldehyde, and benzoic acid in addition to the mixture of cresols. Hydroxylation of phenylacetic acid leads to decarboxylation and gives benzyl alcohol along with phenolic products [2], A mixture of naphthols is produced in radical oxidations of naphthalene, in addition to diols and hydroxyketones [19]. 

I2 is a very weak electrophile. It is just reactive enough to attack the para position of aniline. Phenol ethers are attacked by iodine only in the presence of silver(I) salts (—> Agl + I3 ). Benzene and alkyl benzenes react with I2 only when the iodine is activated still more strongly by oxidation with iodic or nitric acid. 

Cumene (Phenol). Cumene has become the second largest chemical use for benzene. It is produced by alkylating benzene with propylene at elevated temperature and pressure in the presence of a solid acid catalyst. The U.S. production was more than 6.9 billion lb in 1999. Of this, about 96 percent then was converted to phenol. 

Buchet JP. 1988. Determination of phenol and its glucurono- and sulfoconjugates in urine by gas chromatography. In Fishbein L, O Neill JK, eds. Environmental carcinogens method of analysis and exposure measurement Vol. 10—benzene and alkylated benzene. IARC Scientific Publications No. 85. Lyon, France World Health Organization, International Agency for Research on Cancer, 281-286. 

Intramolecular phenol alkylation. Phenols of type 1,3, and 4 when treated with ethylmagnesium bromide in benzene at reflux undergo intramolecular alkylation. These reactions are thought to proceed via o-quinone methide intermediates such as b formulated for the case of 1. These cyclizations fail with NaH or n -butyllithium as... 

In early phenol alkylation studies 61), we noticed that alkylation of phenol with ethylene occurred at 204°C, a temperature much higher than that required for ethylation of the much less nucleophilic benzene nucleus (121°C) under similar conditions. Superficially, at least, this appears to violate the classical laws of electrophilic substitution (24). Closer examination of this system 62, 64), however, showed that phenol, at moderately low temperatures, was specifically adsorbed at sites active for alkylation, thus hindering adsorption of ethylene at these same sites, and preventing generation of the electrophile necessary for attack on the phenyl nucleus. That is, alkylation by a Rideal-type mechanism see Scheme 5) cannot occur until temperatures high enough to desorb phenol from the active sites—and allow ethylene to compete for adsorption— are obtained. In such systems, alkylation can be facilitated by imposition of pressure (in the case of ethylene), or use of more polar or higher... 

Aryl amine intermediates for azo and triphenylmethane dyes, as well as a number of vat dye (anthraquinone) intermediates, are made from compounds such as benzene, alkyl benzenes (toluene and higher homologues), phenol and naphthalene. A limited number of reactions are used to produce the most important dye intermediates, including nitration, reduction, halogenation, sulfonation, /V-alkylation, /V-acylation and alkali fusion33,34. 

The ARALEX process can also be used to extract detergents from aqueous solutions containing actinides for example, contaminated laundry solutions. Detergents from all three classes (anionics such as alkyl sulfates and alkyl benzene sulfonates cationics such as N-benzyl-N-alkyl dimethyl ammonium chloride and nonionics such as polyoxyethylenated alkyl phenols) are... 

In principle, there should not be surface diffusion for nonretained compoimds. On the other hand, the mobile phase is adsorbed at the liquid-solid interface and its properties in this monolayer cannot be the same as those of the bulk solvent. This explains why the limit of the sruface diffusion coefficient when the equilibrium constant tends toward zero is smaller than Dm (Eq. 5.81). Finally, Miyabe has shown that there is a linear free energy relationship between the equilibrium constant of retention and the sruface diffusion coefficient [119]. This has led to the development of a procedure for the derivation of a first approximation of the sruface diffusion coefficient. However, data are available only for alkyl-benzenes and alkyl-phenols at this time. 

This coefficient is the stun of the contributions of pore and surface diffusion. The pore diffusivity can be derived from known correlations (see Chapter 5, subsection 5.2.6, e.g., those of Mackie and Meares [89], Satterfield [90], or Brenner and Gaydos [91]). Therefore, this procedme gives the surface diffusion coefficient. It has been used by Miyabe to derive estimates of the surface diffusion coefficients for alkyl benzenes and alkyl phenols on columns packed with Cjg silica [86,92,93] and on monolithic silica columns [93,94]. They were used by Hong et al. to measure the surface diffusion of rubrene on Symmetry Cig [95]. 

Alkyl phenols have been synthesized by several approaches, including alkylation (CH3-, C2H5-, C3H7-, C4H9-) of a phenol, hydroxylation of an alkyl benzene, dehydrogenation of an alkyl cyclohexanol etc. 

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