P-Methylphenol

Fig. 1. A single step perturbation fails for the mutation of p-methylphenol to p-methoxyphenol because no configuration with a cavity large enough to accommodate the methoxy group is sampled in a simulation of p-methylphenol in water.

The hydrolysis of p bromotoluene with aqueous sodium hydroxide at 300°C yields m methylphenol and p methylphenol in a 5 4 ratio What is the meta—para ratio for the same reac tion carried out on p chlorotoluene" ... 

If t he directing effects of the two groups oppose each other, the more powerful activating group has the dominant influence, but mixtures of products often result. For example, bromination of p-methylphenol yields primarily 2-bromo-4-methylphenol because —OH is a more powerful activator than -CH3. 

Would you expect p-methylphenol to be more acidic or less acidic than unsubstituted phenol Explain. (See Problem 16.74.)... 

The food preservative BHT is prepared by Friedel-Crafts alkylation of p-methylphenol (p-cresol) wnth 2-methyIpropene in the presence of acid BHA is prepared similarly by alkylation of p-methoxyphenok... 

Synonyms AI3-00150 BRN 1305151 CCRIS 647 4-Cresol p-Cresol p-Cresylic acid EINECS 203-398-6 FEMA No. 2337 l-Hydroxy-4-methylbenzene p-Hydroxytoluene 4-Hydroxytoluene p-Kresol l-Methyl-4-hydroxybenzene 4-Methylhydroxybenzene p-Methyl-hydroxybenzene p-Methylphenol NSC 3696 4-Oxytoluene p-Oxytoluene Paracresol Paramethylphenol RCRA waste number U052 4-Toluol p-Toluol p-Tolyl alcohol UN 2076. 

The aryne intermediate from p-iodotoluene can undergo addition of hydroxide ion at the position meta to the methyl group or para to it. The two isomeric phenols are m- and p-methylphenol. 

In the second case, we have the same nonpolar side-chain, but differing polar functions, say p-methylphenol and p-toluidine. We want the phenolic and anilinic functions toward the column, and, therefore, you would select a normal phase column. The nonpolar solvent attracts the aromatic methyl substituents, correctly orienting the molecules for separation. 

To recover the p-xylene, the ether is evaporated and the p-xylene distilled. In the case of p-toluidine and p-methylphenol, once the product is liberated from the corresponding salt, it is extracted from the water by ether. The ether is then evaporated and the desired product is distilled. The order of extraction—acid first, then base—can be reversed. 

Figure 6 Polymer-induced pseudo-chromatographic effect in NMR diffusometry using polyvinylpyrrolidone (PVP) of an MW of 10,000 in deuterated chloroform. Regular DOSY (left) and chrom-NMR (right) on a mixture of benzylalcohol, p-methylphenol and p-xylene mixture. Adapted with permission from Ref. 24. Copyright 2009 American Chemical Society.

Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are antioxidants that are added to foods and many other organic materials to inhibit decomposition caused by reactions with oxygen. Perhaps you have seen these compounds listed among the ingredients on your cereal box at breakfast. (The mechanism of operation for these antioxidants is described in Section 21.8.) Both of these compounds are prepared by Friedel-Crafts alkylation reactions. BHT is synthesized by the reaction of p-methylphenol with 2-methylpropene in the presence of an acid catalyst. 

Phenols are less acidic than carboxylic acids, with values of pKa around 10. Phenols are depro-tonated by (and therefore soluble in) solutions of sodium hydroxide but not by solutions of sodium bicarbonate. Explain how you would use extractions to isolate the three pure compounds from a mixture of p-cresol (p-methylphenol), cyclohexanone, and benzoic acid. 

BUTYLATED H T)ROXYTOLUENE BUTYLHYDRO-XYTOLUENE CAO 1 CAO 3 CATALIN CAO-3 CHEMANOX 11 DBMP DBPC (technical grade) DIBUTYLATED HYDROXYTOLUENE 2,6-DI-tert-BUTYL-p-CRESOL (OSHA, ACGIH) 2,6-DI-tert-BUTYL-1-HYDROXY-4-METHYLBENZENE 3,5-DI-tert-BUTYL-4-HYDROXYTOLUENE 2,6-DI-terc,BUTYL-p-KRESOL (CZECH) 2,6-DI-tert-BUTYL-p-METHYLPHENOL 2,6-DI-tert-BUTYL-4-METHYLPHENOL FEMANo. 2184 4-HYDROXY-3,5-DI-tert-BUTYLTOLUENE IMPRUVOL... 

SYNS 4-CRESOL p-CRESYLIC acid l-HYDROXY-4-METHYLBENZENE p-HYDROXYTOLUENE 4-HYDROXYTOLUENE p-KRESOL D l-METHYL-4-HYDROXYBENZENE p-METHYLPHENOL 4-METHYLPHENOL p-OXYTOLUENE PARAMETHYL PHENOL RCRA WASTE NUMBER U052 p-TOLUOL p-TOLYL ALCOHOL... 

Show the mechanism of the reaction of p-methylphenol with 2-methylpropene and H3P04 catalyst to yield the food additive BHT. 

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