W-Propyl benzene

The dehydrocyclization of alkylaromatics was first described more than four decades ago. In 1936 Moldavskii and Kamusher reported the formation of naphthalene from u-butylbenzene on chromia at 475°C (7, 2). In 1945 Herington and Rideal reported the formation of indene from w-propyl-benzene over chromia-alumina (3). Platinum-containing catalysts were first used for these reactions in 1956 by Kazanskii and co-workers 4-6). 

A large number of other compounds have now been studied including 1-butenebenzyl bromide and allyl bromide substituted benzyl bromides 02 w-propyl benzene 9 6 w-butyl benzene 297 cumene, -butyl benzene and / -cymene and bromobenzene. The work is continuing. 

The fact that n- butyl benzene call be prepared in reasonable yield by the action of sodium upon a mixture of bromobenzene and w-butyl bromide can be partly explained on the assumption that n- butyl bromide reacts with phenyl-sodium more rapidly than does bromobeuzene. It is interesting to note that n-butylbenzene can be prepared either from benzylsodium and w-propyl bromide or from phenylsodium and n-butyl bromide (Section VI,29). 

The ketones are readily prepared, for example, acetophenone from benzene, acetyl chloride (or acetic anhydride) and aluminium chloride by the Friedel and Crafts reaction ethyl benzyl ketones by passing a mixture of phenylacetic acid and propionic acid over thoria at 450° and w-propyl- p-phenylethylketone by circulating a mixture of hydrocinnamio acid and n-butyrio acid over thoria (for further details, see under Aromatic Ketones, Sections IV,136, IV,137 and IV,141). 

M-Butylbenzene has been prepared by the action of sodium (a) on benzyl chloride or bromide and w-propyl bromide without diluents,1 or (b) on n butyl bromide and bromobenzene without a solvent2 or in benzene 3 by a Clemmensen reduction of ra-butyr-ophenone 4 and by the action of benzylmagnesium chloride on M-propyl />-toluenesulfonate.5 Other procedures do not appear to be of preparative value. 

Off-gas analyses were done by mass spectrometry and reactor effluent samples were analyzed by glc. Most of the glc work was done with an 8-foot 1/4-inch OD column containing 10% SE-30 on acid washed Chromsorb W. However, the separation of n-propyl-benzene from cumene had to be done with a dual 3/16-inch copper column consisting of a 12-foot section having 10% Bentone 34 and 10% Dow Corning silicone gum 550 on 60-80 mesh acid washed Chromsorb W and a 6-foot section containing 20% Apiezon L on 60-80 mesh acid washed Chromsorb P. 

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... 

Under the given conditions the main reaction of n-butylbenzene is the partial or complete hydrogenolysis of the side chain to form n-propyl-benzene, ethylbenzene, toluene, and benzene. In addition hydrogenation of the benzene ring, contraction of the hexamethylene cycle to a five-membered one, hydrogen cleavage of the latter, formation of xylenes, methylpropylbenzenes, and diethylbenzenes, and dehydrocyclization of the side chain of w-butylbenzene to naphthalene are also observed. 

W (2 -Met hyl -1-propenyl )benzene 4-(2-Met hyl propenyl )morphol I ne 2-(2-Met hyl propoxy)et hanol Met hyl propyl ami ne 1-Met hyl-2-propyl benzene 1-Met hyl -3-propyl benzene 1-Met hyl -4-propyl benzene c/si-Met hyl-2-propyl cycl opent ane... 

Draw the structures of (a) w-butylbenzene, (b) (3-phenyl-1-propyl) benzene, (c) cyclopentyl benzene, and (d) 2,5,-diphenyldecane. 

Mixtures of Benzene with Alcohols.—Benzene is much more easily obtained in quantity than hexane, and behaves in a somewhat similar manner. The lower alcohols are miscible with benzene in all proportions but while methyl, ethyl, isopropyl, w-propyl, tertiary butyl and isobutyl alcohols form mixtures of maximum vapour pressure with that hydrocarbon, isoamyl alcohol does not, and it is practically certain that no alcohol of higher boiling point would form such a mixture. 

FIGURE 5.21 High-speed isothermal separation of a 20-component mixture using a pressure-tunable column ensemble. The plots of band position versus time were obtained from the retention factors for the mixture components on the two separate colimms along with the column dimensions and the inlet, outlet and junction point pressures. A window diagram was used to determine the junction point pressure for the complete separation of the first 14 components. Compounds are 1, n-pentane 2, methyl alcohol 3, 2,2-dimethylbntane 4, 1,1,1-trichloroethane 5, cyclopentane 6, w-hexane 7, w-propyl alcohol 8, cyclohexane 9, benzene 10, n-heptane 11, l,2-dichloropropane 12, toluene 13, n-bntyl alcohol 14, w-octane 15, 2-hexyl alcohol 16, n-pentyl alcohol 17, ethylbenzene 18, m-xylene 19, w-nonane 20, o-xylene. 

Cp == concentration (%w/w) of n-propyl benzene as determined on the squalane column. 

The /5o-propyl benzene radical (Ar ) is formed in reaction azodiiso-butyronitrile (ADEN) with ArH (1) of which in the presence of oxygen it is formed peroxy radical ArOO (2). Continuation of considerably-chain oxidation proceeds in reaction ArOO with ArH (3) with a reaction constant kj (according to Ref [A]k =. 15 I mol c ) inhibition - in reaction ArOO with antioxidant InOH (4) with a reaction constant k. Specific reaction rate value (k ) defined from dependence A [02]/[ArH] = -kjk An (1-t X T ) where, [ArH] - concentration ArH (7.18 mol l ), A [O2] - the quantity turned sour-sort, entered reaction with ArH. The season of inhibition of oxidation ArH oxygen with antioxidant participation (x) and value of stopping of chain (f) at constant speed initiation (W. = 1.5x10 mol H s ) defined a gasometric method (Fig. 1). 

The crystal of 2 OPr recrystallized from EtOH/H20 solution, and the mixed crystal of the same ethyl and propyl cinnamate derivatives (2 OEt and 2 OPr), on photoirradiation for 2h at room temperature with a 500 W super-high-pressure Hg lamp, afforded the highly strained tricyclic [2.2] paracyclophane (2 OEt-2 OPr-cyclo) crystal quantitatively (Maekawa et ai, 1991b). A crystal structure analysis was carried out of a single crystal of the complex of 2 OEt-2 OPr-cyclo with HFIP (recrystallization solvent) in a 1 2 molar ratio. Fig. 13 shows the molecular structure of 2 OEt-2 OPr-cyclo viewed along the phenylene planes. The short non-bonded distances and deformation of the benzene rings, as seen in Fig. 13, are common to those of [2.2] paracyclophanes, as previously reported (Hope et ai, 1972a,b). 

Di- -propyl-6,6 -biguaiacol (IV) was oxidized under the same standard conditions. The degradation products were isolated and determined quantitatively by practically the same procedures as mentioned above. The isolated 2-hydroxy-3-methoxy-5-w-propylbenzoic acid (VI) recrystallized from benzene-w-hexane (m.p., 119°-120.5°C.), was identified by elemental analysis and by mixed melting point with an authentic sample. Elemental analysis calculated C, 62.85% H, 6.72% found C, 62.64% H, 6.80%. 

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