W Propylbenzene

This contains only a small proportion of unsaturated compoundsthese are easily removed by three washings with one tenth of the volume of concentrated sulphuric acid (compare Section III,7, Note 2). The resulting pure w-propylbenzene boils at 158-159°. 

After a few minutes, the bulk of the water layer is removed by a siphon and the clear ethereal solution decanted, so far as possible, into a 2-1. flask. The remaining mixture is filtered through a glass-wool plug into a separatory funnel, and after removal of the aqueous portion, the remaining ethereal solution is added to that in the flask. An efficient fractionating column is attached, and the ether distilled on the water bath the residue is then fractionated and collected as pure w-propylbenzene boiling at 154-158°. The yield is 133-156 g. (55-65 per cent of the theoretical amount). 

Figure 12 Cross-sections of CA host channels sliced parallel to the direction of the channel (carbon and hydrogen atoms are represented by gray and white, respectively) with arrays of included guest molecules (hydrogen atoms are omitted for clarity, and carbon and oxygen atoms are represented by open and filled circles, respectively), (a) toluene, (b) w-propylbenzene, (c) n-butylbenzene, (d) w-hexylbenzene, (e) p-xylene, and (f) methyl methacrylate.

Problem 12.17 Describe simple chemical tests (if any) that would distinguish between (a) w-propylbenzene and i -chlorotoluene (b) benzene and toluene ... 

Reactions of toluene, ethylbenzene, and w-propylbenzene with ions having recombination energies ranging from 9.26 eV (NO ) to 15.58 eV (NJ) were studied at 300 K in a selected ion flow tube (SIFT) yielding information regarding the role of electronic energy in these reactions. These... 

Alkylation with compounds containing more than two carbon atoms almost always gives products containing branched chains thus with benzene w-propyl chloride gives isopropylbenzene and not w-propylbenzene. The occasional exceptions — alkylation without isomerization — occur when the reaction takes place at low temperatures or involves long-chain alkyl groups.537,538... 

The relative content in the catalysates of the products of partial and complete isopropylbenzene dealkylation is illustrated by the experiment with 20 % Ni-AUOs at 465° 25 atmospheres and 0.8 space velocity. In this case the catalysate contained 32% benzene, 20.2% toluene, and 12.8% ethylbenzene. Besides this main reaction, other conversions also take place under these conditions namely, hydrogenation of the benzene ring to the hexamethylene cycle, contraction of the latter to a five-membered ring, hydrogenolysis of the five-membered ring with the formation of alkanes, partial isomerization of isopropylbenzene to w-propylbenzene and methyla-tion of the benzene nucleus by methylene radicals arising from partial decomposition of the cyclanes. 

Molecular rearrangements involving hydride, H , and alkyl, R, shifts become possible when a carbocation or a polarized cation-like complex is an intermediate in a reaction. Thus, the aluminum chloride-promoted reaction of 1-bromopropane with benzene gives w-propylbenzene (1) and isopropylbenzene (2) in a ratio of about 1 2 (Eq. 15.10). As shown in Scheme 15.1, the formation of 2 is explained by a 1,2-hydride rearrangement of the primary carbocation-like complex 3 to produce the secondary carbocation 4. The formation of comparable amounts of 1 and 2 in the reaction means that the rate of addition of 3 to benzene followed by deprotonation to give 1 must be competitive with that for isomerization of 3 to the secondary ion 4, which is the precursor of 2. In mathematical terms, fc2[ ][C6H6] must be similar to since these expressions measure the rates of formation of 1 and 2, respectively. 

Figure 1.11 Plot of the logarltha of the adjusted retention tine against the reciprocal of coluan tesperature for two honologous series of n-alkane and n-alkylbensenes (and ortho-xylene) on a 2 seter 20% (H/H) colunn of tetrahutylaanoniua 4-toluenesulfonate coated onto Chronosorb (W-AH). Solute identification, 1 decane, 2 - undecane, 3 - dodecane, 4 trideceme, 5 tetradecane, 6 -pentadecane, 7 > benzene, 8 - toluene, 9 - ethylbenzene, 10 -propylbenzene, 11 - ortho-xylene, and 12 - butylbenzene.

Ir(III) complexes can also be used to catalyze the hydroarylation of olefins [5, 6], The catalyst precursors (acac-0,0)2Ir(Ph)(L) (L= pyridine or H20) and [Ir(w-acac-0,0,C3)(acac-0,0)(acac-C3)]2 have been reported and are depicted in Scheme 3, with representative catalytic reactions. Among these catalyst precursors, (acac-0,0)2Ir(Ph)(H20) has been demonstrated to be the most active system [5], The lin-ear-to-branched ratios observed for Ir(III) catalyzed reactions of a-olefins are remarkably similar to those obtained using TpRu(CO)(NCMe)(Ph). For example, hydrophenylation of propene using 11 r (a-acac- O, O,C ) (acac-O, O) (acac-C3) ]2 as catalyst produces a 1.6 1 ratio of linear propylbenzene to cumene (identical to the ratio observed using the Ru(II) catalyst). Similar to the TpRu(CO)(NCMe)(R) catalysts, the regioselectivity of hydroarylation of ethylene that incorporates monoalkyl arenes produces meta- and para-disubstituted alkyl arenes in approximately 2 1 ratio without observation of ortho-disubstituted products. 

W.L. Backes at the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, is studying the toxicological significance of the metabolism in rats and rabbits of alkylbenzenes (including toluene, xylenes, ethylbenzene, and />propylbenzene), which are major constituents of gasoline. Specifically, the identification of changes in the metabolic fate of the alkylbenzenes due to their prior administration, the effects of age, sex, and strain differences, the effects of exposure time and exposure to hydrocarbon mixtures, and the effect of hydrocarbon... 

Similar trends of increasing heat of adsorption with C-number are seen for the iso-alkanes. For H-ZSM-5 their adsorption is less favoured than for the -alkanes whereas they are more favoured in the large-pore solids. This results from steric hindrance in the ZSM-5. As a more marked consequence of the steric features, the packing of the iso-alkanes is much less efficient than of the w-alkanes in H-ZSM-5, so that the uptake of iso-butane is only around one half of that of -butane. This ratio is much closer to 1 in large-pore mordenite (0.85) and H-Y (1). Still larger steric effects were noticed for the adsorption of bulky alkylbenzenes on H-ZSM-5, where initial heats of adsorption of isopropyl- and -butyl-benzene are much lower (50 and lOkJmol, respectively) than those observed for ethyl- and -propylbenzene ca. 80kJmol ). ... 

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