N Butylbenzene

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

The n-butylbenzene contains some unsaturated hydrocarbons these can be removed by repeated shaking with small quantities of concentrated sulphuric acid (see Section III,7,No[Pg.512]

Ethylbenzene. Prepare a suspension of phenyl-sodium from 23 g. of sodium wire, 200 ml. of light petroleum (b.p. 40-60°) and 56 3 g. (50 9 ml.) of chlorobenzene as described above for p-Toluic acid. Add 43 -5 g. (30 ml.) of ethyl bromide during 30-45 minutes at 30° and stir the mixture for a further hour. Add water slowly to decompose the excess of sodium and work up the product as detailed for n-Butylbenzene. The yield of ethylbenzene, b.p. 135-136°, is 23 g. 

For concentrated polystyrene solutions (c>c ) in n-butylbenzene, Graessley and co-workers [36] observed that the shift factor hconc depends on the number of entanglements per macromolecule E. 

For concentrated solutions of polystyrene in n-butylbenzene, Graessley [40] has shown that the reduced viscosity r red Cnred=(r ( y)- rls)/(rlo rls)) can be represented on a master curve if it is plotted versus the reduced shear rate (3 ((3= y/ ycnt= y-A0). For semi-dilute solutions a perfect master curve is obtained if (3 is plotted versus a slope corrected for reduced viscosity, T corp as shown in Fig. 16. 

HS-GC methods have equally been used for chromatographic analysis of residual volatile substances in PS [219]. In particular, various methods have been described for the determination of styrene monomer in PS by solution headspace analysis [204,220]. Residual styrene monomer in PS granules can be determined in about 100 min in DMF solution using n-butylbenzene as an internal standard for this monomer solid headspace sampling is considerably less suitable as over 20 h are required to reach equilibrium [204]. Shanks [221] has determined residual styrene and butadiene in polymers with an analytical sensitivity of 0.05 to 5 ppm by SHS analysis of polymer solutions. The method development for determination of residual styrene monomer in PS samples and of residual solvent (toluene) in a printed laminated plastic film by HS-GC was illustrated [207], Less volatile monomers such as styrene (b.p. 145 °C) and 2-ethylhexyl acrylate (b.p. 214 °C) may not be determined using headspace techniques with the same sensitivities realised for more volatile monomers. Steichen [216] has reported a 600-fold increase in headspace sensitivity for the analysis of residual 2-ethylhexyl acrylate by adding water to the solution in dimethylacetamide. 

The NMR spectrum of the spent solvent from E10 is shown in Figure 3. Tetralin and naphthalene absorption peaks are evident in this spectrum, and the peaks at positions 1, 2 and 3 are due to decal ins and in part to methylindan and n-butylbenzene. Methyl in-dan and n-butylbenzene were detected and analyzed by GC-MS. In Figure 3, the large difference in amplitude between the Har Hx and Hj absorptions of Tetralin show that protium was incorporated to a greater degree into the position than into the other positions. The spectrum also shows that the H absorption of the naphthalene in the spent solvent is much more intense than the absorption. 

Ring closure between an adjacent pair of aromatic substituents is also possible an example is the formation of indan from l-methyl-2-ethyl-benzene 11,109). In fact, Csicsery 109) found that the rate of cyclization of l-methyl-2-ethylbenzene to indan over platinum was somewhat faster than that of n-butylbenzene to methylindan, indicating that kinetically there is nothing to be gained by having ring closure at an aromatic carbon... 

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