Aromatic compounds isopropylbenzene

Thus cumene [98-82-8] (1-methylethylbenzene, 2-phenylpropane, isopropylbenzene), is a substituted aromatic compound ia the benzene (qv),... 

Aromatic compounds such as benzene react with alkyl chlorides in Ihe presence of AlCl i catalyst to yield alkylbenzenes. The reaction occurs through a carbocation intermediate, formed by reaction of the alkyl chloride with AICI3 (R—Cl + A1CI 1 - U+ + AICl4 ). How can you explain the observaiion that reaction of benzene with 1-chloropropane yields isopropylbenzene as the major product ... 

The radiolysis of other aromatic compounds is not understood with any more certainty than that of benzene and is sometimes complicated by additional sites for reaction. The reader is referred to the following publications toluene, Cooper and Thomas S , Weiss and Collins ethylbenzene, Hentz and Burton isopropylbenzene, Hentz , Sworski et t-butylbenzene, Sworski et stilbenes, Caldwell et... 

The partial oxidation of polyalkylated aromatic compounds is also observed. o-Xylene is oxidized to o-toluic acid by heating with ozone and oxygen at 115-120 °C in the presence of cobalt acetate in acetic acid (yield 77%) [68] or by refluxing with dilute nitric acid (1 2) (yield 53-55%) [463]. In p-cymene (p-isopropylbenzene), the isopropyl group is oxidized in preference to the methyl group to give a 51% yield of p-toluic acid on refluxing with dilute nitric acid (1 36) [464]. On the contrary, biochemical oxidation with Nocardia strain 107-332 converts p-cymene into p-isopropylbenzoic acid [1071]. 

For alkylation of aromatic compounds with olefins, alcohols and alkyl halogenids, acidic zeolite catalysts may also be applied as it shown decads ago [1]. Alkylation of benzene with propene over acid catalysts yields isopropylbenzene (cumene) accompanied by formation of n-propylbenzene, di-isopropylbenzenes and propene oligomers as main by-products. 

Some of the factors controlling orientation and reactivity in metallation of aromatic compounds have been discussed83 in the light of reactions of alkyl-sodiums and -potassiums with isopropylbenzene. 

The following aromatic compounds have been detected by GLC in small amounts in Evernia prunastri (L.) Ach. benzene, toluene, isopropylbenzene, m-ethyltoluene, mesitylene, 1,2,3-trimethylbenzene, isobutylbenzene, bro-mobenzene, l,2-dimethyl-3-ethylbenzene, 1-chloro-2,4-dimethoxy-6-methylbenzene, a,p-dimethylstyrene, naphthalene, bis-(p-tolyl)-1,2-ethane, phenol, 2-chloro-3-methoxy-5-methylphenol, phthalic acid and N,N-dimethyl-p-toluenesulfonamide (Gavin and Tabacchi 1975), and a,a-dimethylstyrene,... 

Alkylation. Friedel-Crafts alkylation (qv) of benzene with ethylene or propylene to produce ethylbenzene [100-41 -4], CgH10, or isopropylbenzene [98-82-8], C9H12 (cumene) is readily accomplished in the liquid or vapor phase with various catalysts such as BF3 (22), aluminum chloride, or supported polyphosphoric acid. The oldest method of alkylation employs the liquid-phase reaction of benzene with anhydrous aluminum chloride and ethylene (23). Ethylbenzene is produced commercially almost entirely for styrene manufacture. Cumene [98-82-8] is catalytically oxidized to cumene hydroperoxide, which is used to manufacture phenol and acetone. Benzene is also alkylated with C1Q—C20 linear alkenes to produce linear alkyl aromatics. Sulfonation of these compounds produces linear alkane sulfonates (LAS) which are used as biodegradable deteigents. 

In distinct contrast to the faujasites, the intermediate-pore zeolites ZSM-5 and ZSM-11 exhibited a marked preference for n-paraffins relative to aromatics. As can be seen from Table II, both H-ZSM-5 and H-ZSM-11 preferentially sorbed n-nonane from mixtures of nonane and p-xylene dissolved in an inert, non-sorbable solvent, 1,3,5-tri-isopropylbenzene. Selectivity factors greater than 40 were observed, despite the fact that both compounds were readily sorbed when higher zeolite/sorbate ratios were used. Highly selective sorption of n-heptane relative to naphthalene, and n-tetradecane relative to 1-phenyloctane, was also observed with H-ZSM-5. 

This sensor did not respond to the selected compounds as predicted, and in the first appraisal of data no significant relationship was found for the set of hydrocarbons tested. The biosensor response could be better explained for the set of aromatic hydrocarbons, insofar as these were more similar to isopropylbenzene. The data were remodeled, resulting in an improved regression model ... 

Carbonium ions can be generated at a variety of oxidation levels. The alkyl carbocation can be generated from alkyl halides by reaction with a Lewis acid (RCl + AICI3) or by protonation of alcohols or alkenes. The reaction of an alkyl halide and aluminium trichloride with an aromatic ring is known as the Friedel-Crafts alkylation. The order of stability of a carbocation is tertiary > secondary > primary. Since many alkylation processes are slower than rearrangements, a secondary or tertiary carbocation may be formed before aromatic substitution occurs. Alkylation of benzene with 1-chloropropane in the presence of aluminium trichloride at 35 °C for 5 hours gave a 2 3 mixture of n- and isopropylbenzene (Scheme 4.5). Since the alkylbenzenes such as toluene and the xylenes (dimethylbenzenes) are more electron rich than benzene itself, it is difficult to prevent polysubsiitution and consequently mixtures of polyalkylated benzenes may be obtained. On the other hand, nitro compounds are sufficiently deactivated for the reaction to be unsuccessful. 

Among the classes of compounds in crude oil, the alkanes, cycloalkanes, and aromatic fractions contain compounds that are volatile and are described in more detail in this chapter. The NSO compounds, resins and asphaltenes, and organometalhc compounds are nonvolatile and, in general, are less mobile in the environment. A discussion of these compounds is beyond the scope of this chapter. Examples of some of the volatile hydrocarbons present in cmde oil for the major compound classes are shown in Figure 6. Benzene, toluene, xylenes, ethylbenzene, isopropylbenzene, naphthalene, methyl- and dimethyl-naphthalenes are among the most important volatile aromatic hydrocarbons, because they are widely used and, once released into the environment, their mobility and toxicity make them a significant environmental threat (Merian and Zander, 1982). The occurrence of these compounds in the environment is almost exclusively anthropogenic, with the exception of natural hydrocarbon seeps. 

EC>8-EC16, using EPA RfDs (all the same value) for two compounds (cumene [isopropylbenzene] and naphthalene) as a surrogate and an RfC for C9 aromatics (hi-flash aromatic naphtha). 

Aromatic EC>9-EC16 Fraction. Studies measuring the rate and extent of absorption in humans or animals following inhalation exposure to naphthalene or the monomethyl naphthalenes were not available, but observations of systemic health effects in humans and animals provide qualitative evidence of absorption of these indicator compounds (ATSDR 1995e). Studies of humans following inhalation exposure to isopropylbenzene (cumene) indicated a retention percentage of about 50%... 

Aromatic EC>9-EC16 Fraction. Data regarding the rate and extent of dermally administered isopropylbenzene (cumene), naphthalene, or monomethyl naphthalenes were restricted to observations of systemic effects in humans and animals following dermal exposure to these compounds (ATSDR 1995e EPA 1987a, 1997b). 

Tr he stability of aromatic hydrocarbons to radiation has been cited so frequently in the literature that it has come to be accepted (5, 6) as a characteristic of aromaticity, a consequence of electron delocalization. These conclusions are based on the results of irradiations in the liquid phase. That they may not apply to the isolated aromatic molecule, however, is suggested by the few reported studies of the radiolysis of aromatic hydrocarbons in the vapor phase. Such studies have thus far been limited to two compounds—benzene (8, 10, 11) and isopropylbenzene (cumene) (9), and differences in the character of the radiation or the conditions of irradiation preclude a simple assessment of the effect of phase on these systems. 

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