Isopropyl-p-xylene

GLC analysis of reaction mixture from miniscale alkylation of p-xylene with 1-bromopropane. Numbers in parentheses are retention times in minutes and peak areas, respectively. Peak 1 solvent peak 2 p-xylene (1.7, 14417) peak 3 isopropyl-p-xylene (1.8, 71721) peak 4 n-propyl-p-xylene (2.0, 229275). Column and conditions 0.25-mm X 25-m AT-1 with 100% dimethylsiloxane as stationary phase flowrate 1.2 mL/min temperature 185 °C. 

Consider the spectral data for isopropyl-p-xylene (Figs. 15.10 and 15.11). 

Quantity Benzene Toluene Isopropyl- benzene Ethyl- benzene P- Xylene m- o-Xylene Xylene Tetra- line... 

Make determinations in triplicate on the flash point of standard p-xylene and of standard isopropyl alcohol which meet specifications set forth in Appendix A2. Average these values for each compound. If the difference between the values for these two compounds is less than 15 F (8.5 C) or more than 27 F (l6 C), repeat the determinations or obtain fresh standards (Note 7)... 

More recent work applying modem analytic techniques for reliable identification of products revealed that the product distribution was almost independent of the temperature (the normal isopropyl ratio was 34 66 at — 18°C, and 30 70 at 80°C).116 In contrast, alkylation of p-xylene exhibited strong temperature-dependent regioselectivity117 [Eq. (5.24)] due to obvious isomerization equilibria ... 

In a typical experiment, two solutions were prepared A - contained 0.3g p-xylene, 0.3g l,3-di(tri-fluoromethylbenzene, and 11.4g 1,3,5-tri-isopropyl-benzene B - contained l.Og n-nonane, l.Og mesitylene and 6.0g 1,3,5-tri-isopropylbenzene. 3.0g of solution A was added to l.Og H-ZSM-5 at room temperature the sorption of p-xylerie was monitored over a period of several hours by gas chromatography. When the sorption had reached a constant value, 0.6g of solution B was added. The resulting desorption of p-xylene and the adsorption of n-nonane was monitored by gas chromatography. In these experiments, the 1,3-di(trifluoro-methyl)benzene and mesitylene behaved exclusively as non-sorbing internal standards. 

The preferential adsorption behavior of poly(vinylpyrrolidone) (PVP) in binary solvent containing aromatic components has been also studied [110]. In this case, it was concerned with the influence of the chemical structure of different binary solvents in the preferential adsorption of this polymer. 2 - propanol - cumene, 2 -propanol - mesitylene, 2 - propanol - p-xylene, 2 - propanol - ethylbenzene and 2 - propanol - toluene. Figure 1.15 shows the variation of X with the solvent composition. In both cases aromatic components are adsorbed in the range 0 to 40%, but the amount of adsorbed molecules is rather different for the two isomers. This result could be explained in terms of steric hindrance due to the isopropyl groups of cumene, which would be reflected in the lower X value. 

Hydroxylation of benzene to phenol using hydrogen peroxide in the presence of heteropoly compounds was observed in this study. Other aromatic hydrocarbons that were used as substrates were toluene, ethylbenzene, o,p-xylene and isopropyl benzene under homogeneous conditions. Both side chain oxidation and ring hydroxylation were observed in presence of hydrogen peroxide. For example, toluene gave benzyl alcohol, benzaldehyde, o,p-cresols in presence of hydrogen peroxide, whereas benzaldehyde and benzyl alcohol were observed in presence of t-BuOOH. 

P-17 - Highly selective isopropylation of xylenes catalyzed by zeolite Beta... 

Heating the solution of A,A-di(isopropyl)ethylamine, the iridium catalyst 8.111 and t-butylethylene (hydrogen acceptor) at 90 °C in p-xylene for 5 h, for example, yields vinyl A,A-dipropylamine with a 98 % yield, as shown in Eq. (8.33) [153]. 

FIGURE 7 Generic solvent-exchange method, direct injection GC/FID. From bottom to top blank injection and GC volatiles test solution. Peaks I, methanol 2, n-pentane 3, ethanol 4, acetone 5 isopropyl alcohol 6, acetonitrile 7, methyl acetate 8, methylene chloride 9 methyl tertiary butyl ether 10, n-hexane 11, propanol 12, methyl ethyl ketone 13, ethyl acetate 14, sec-butanol 15, tetrahydrofuran 16, cyclohexane 17, hexamethyidisiloxane 18, benzene 19, n-heptane 20, butyl alcohol 21, 1,4-dioxane 22, methyl isobutyl ketone 23, pyridine 24, toluene 25, isobutyl acetate 26, n-butyl acetate 27, p-xylene 28, dimethylacetamide 29, solvent impurities. 

Vapor-phase alkylation of benzene, toluene, 0-, m-, p-xylenes and fluorobenzene with alkyl halides was studied with Nafion-H as a catalyst.Conversion of as high as 87% (based on isopropyl halide) was obtained at 353 K from a 5 2 mixture of benzene tmd the chloride. The catalyst showed no deactivation. Alkylation ability follows the order RF > RCl > RBr and secondary > primary. The only product obtained in the alkylation of toluene with propyl chloride was cymenes (isopropyltoluenes) no propyl-toluenes were detected. This indicates the intermediacy of the isopropyl cation in the alkylation reaction. 

From the relative roles of the primary and tertiary radicals which are statistically formed on p-cymene, the termination constant of p-cymene should lie between that of cumene and that of toluene or xylene. Experimentally, this interpretation can be easily checked (12) by comparing the oxidation of p-cymene diluted by benzene with aromatic hydrocarbon mixtures having equal concentrations of methyl and isopropyl groups in comparable mixtures (Table V). 

A solution of 19.4 g N-2,4-dimethylphenyl-N -methylformamidine and 0.3 g p-toluenesulphonic acid in 195 ml dry xylene was refluxed under anhydrous conditions for 48 h, causing the evolution of methylamine. The xylene was distilled off under reduced pressure to give l,5-di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triaza-penta-l,4-diene, melting point 88°-89°C (crystallized twice from isopropyl). 

Further Reduction to a Hydrocarbon. In the reduction of benzo-phenone with aluminum ethoxide the formation of 7% of diphenyl-methane was observed. When benzohydrol was treated with aluminum ethoxide under the same conditions, 28% reduction to diphenylmethane occurred.12 In these reactions acetic acid, rather than acetaldehyde,-was formed from the ethoxide. Aluminum isopropoxide does not give this type of undesirable reaction with this reagent, pure benzohydrol is easily obtained in 100% yield from benzophenone.6 37 However, one case of reduction of a ketone to the hydrocarbon has been observed with aluminum isopropoxide.17 When 9, 9-dimethylanthrone-10 (XU) was reduced in xylene solution, rather than in isopropyl alcohol, to avoid formation of the ether (see p. 190), the hydrocarbon XUII was formed in 65% yield. The reduction in either xylene or isopropyl alcohol was very slow, requiring two days for completion. 

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]. 

Xylene, diglyme, and trifluoroborane-diethyl etherate are purified as in Sec. Al. Tripropylborane of b.p. 159o11 used in this preparation consists of a mixture of 93 % tripropylborane and ca. 7% isopropyl-dipropylborane.14... 

Off-white fine powder with a tendency to form easily friable aggregates slight musty odor. Softening begins at 108-117, melting starts at 113-122 and is completed at 144-153. Soly (g/100 ml) at 25 acetone 18.2. DMSO 23.8, distilled water 0.13 (p-isomer), 0.22 (m-isomer), n-heptane 0.04, isopropyl alcohol 14.4, methanol 24.4, methylene chloride 30.0, toluene 3.9. Soly (g/100 g) at 25 xylene < 5, DMF 30. Partition coefficient in n-octanol/water 35 (p-isomer), 66 (m-isomer). LDM In rats, rabbits (mg/kg) > 5000, 4500 orally, > 2000, > 2000 dermally (Hedlund, Anderson). 

Nitric acid and nitrogen oxides are assuming new significance as oxidizing agents. Toluic acids may be made by the nitric acid oxidation of xylenes p-toluic acid is obtained from oxidation of p-cymene through the oxidation of the isopropyl group. Nitric acid in the presence of sulfuric acid and a... 

Properties Wax sol. in hot alcohol, carbon disulfide, chloroform, ether, benzene, petrol, ether, isopropyl ether, naphtha, pyridine, toluene, xylene, turpentine insol. in water sp.gr. 0.975-0.984 m.p. 50-56 C acid no. 6-20 iodine no. 4-15 sapon. no. 210-237 flash pt. > 200 C ref. index 1.450-1.4560 (60 C) dielec, const. 3.1-3.2 Kotamite [IMERYS]... 

Xincure ITX-2. See 2-Isopropyl thioxanthone Xincure MBP. See 4-Methoxybenzophenone Xincure MBZ. See 4-Methylbenzophenone Xincure PBZ. See p-Phenylbenzophenone Xincure TMBZ. See 2,4,6-T ri methyl benzophenone Xinsorb BP-4. See Benzophenone-4 Xinsorb UV-1. See Ethoxycarbonylphenyl)-N -methyl-N -phenylformamidine Xinsorb UV-9. See Benzophenone-3 Xinsorb UV-A. See Acetanisole Xinsorb UV-P. See Drometrizole X-Link 2833, X-Link 2893, X-Link 5627. See Vinyl acrylic copolymer XLPE. See Polyethylene, crosslinked XO White. See Calcium monocarbonate XP-36P. See Sodium hexametaphosphate X-Pand R . See Food starch, modified XPE. See Polyethylene, crosslinked XPS. See Polystyrene, expandable XSA 80, XSA 90, XSA 95, XSA. See Xylene sulfonic acid... 

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