On the preparation of some hydrocarbons of the mixed aliphatic‐aromatic or aliphatic‐alicyclic type containing 22 to 38 C‐atoms

Abstract

The properties of hydrocarbons containing a long aliphatic chain in which aromatic or alicyclic rings occur as, substituents. are of importance for the examination of high-boiling petroleum fractions and products obtained from them, such as lubricating oils. Of the hydrocarbons described in this paper dicetylbenzene has not been described in the literature: the remaining products have already been prepared by other investigators: except for octadecylbenzene and for cetylbenzene, the statements of the earlier authors do not guarantee that the desired hydrocarbon was obtained in the pure state.The degree of purity of the preparations obtained by us is not easy to Idetermine. As these hydrocarbons can only be distilled at a low pressure, a purification of the final product by ver)r sharp fractional distillation is not possible. In some cases the purity could not be checked by determination of a cooling curve, owing to the. very low rate of crystallization. A reasonable degree of purity of the final products could only be guaranteed, therefore, by using pure starting materials and by purifying the synthesized intermediate products as thoroughly as possible.The properties of the cetylbenzene and octadecylbenzene prepared by us are in good agreement with the statements of some earlier authors. Our preparations of the hydrocarbons IV, V I and VII no doubt have a much higher degree of purity than the preparations obtained by earlier authors. In this paper we give the refractive indices for 1 = 5876 and the specifics gravities. In a subsequent paper we intend to publish the refractive indices at other wave lengths and to. discuss the refractometric constants. An attempt to prepare dicetylbenzene by applying the W ii r t z reaction to a mixture of p-dibromobenzene and cetyl iodide was not successful, as dicetyl (C,,H,,) was formed almost exclusively. W e therefore prepared l-cetyl-

Solid−Liquid Equilibria under High Pressure of Nine Puren-Alkylbenzenes

“…Table 3 presents the deviations between the melting temperatures measured in this study at atmospheric pressure and those previously reported in the literature. 21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] No data have been found about 1-phenylundecane, 1-phenyltridecane, and 1-phenylpentadecane. A high disparity can be noticed among the different results for some compounds, e.g., a gap greater than 30 K between the extreme melting temperatures reported for 1-phenylhexadecane.…”

“…There are two explanations for this phenomenon. First, some results are quite dated, and in the past, solid-liquid transitions were often measured on cooling rather -0.3 phenylC 18 302 27 5.9 270.6 21 -0.9 303 33 4.9 phenylC 14 282 24 7.1 306 34 1.9 282.8 25 6.3 308 28,35 -0.1 phenylC 16 280.0 26 19.5 309 36-39 -1.1 295 27 4.5 310 40 -2.1 298 28 1.5 phenylC 19 298.2 41 4.4 300 29,30 -0.5 302. than on heating, involving an underestimation of the melting temperatures particularly for compounds like n-alkylbenzenes for which subcooling is important. Second, as mentioned above, almost all studied compounds present a metastable solid phase, the melting temperature of which is lower than the one of the stable phase.…”

“…In this study, the melting temperatures of nine n-alkylbenzenes between 1-phenylundecane and 1-phenylnonadecane have been measured as a function of pressure in the (0.1 to 100) MPa range. Most of these compounds have already been studied at atmospheric pressure by several authors, [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] but a review of the related results has shown their inaccuracy or inconsistency. The aim of this study is to clarify those results by proposing more reliable values.…”

Perturbation of Cope's Rearrangement: 1,3,5-Triphenylhexa-l,5-diene. Chameleonic or Centauric Transition Region?

“…This stabilization is substantially greater than that expected of either the 1,3-diphenyl moiety (−8.1 kcal mol -1 ) or the 5-phenyl moiety (−6.8 kcal mol -1 ) working alone in a C 2h chameleonic domain (Figure ). Here, too, there is a possibly significant shortfall from the full centauric expectation of their sum, −14.9 kcal mol -1 , based on the two stabilizing groups working optimally and independently 2 Specific Rate Constants and Derived Activation Parameters for the Reversible Rearrangement of 1,3,5-Triphenylhexa-1,5-diene-6- 13 C in Benzene- d 6 T , °C k 1 × 10 6 s -1 a 121.2 ± 0.1 1.73 ± 0.01 132.0 ± 0.1 4.65 ± 0.06 144.6 ± 0.1 13.33 ± 0.10 152.1 ± 0.1 24.61 ± 0.11 164.8 ± 0.1 64.81 ± 0.31Arrhenius parameters E a = 28.49 ± 0.09 kcal mol -1 log A = 10.03 ± 0.09 Eyring parameters b Δ H ⧧ = 27.7 ± 0.09 kcal mol -1 Δ S ⧧ = −15.4 ± 0.3 kcal mol -1 K -1 a Calculated by linear regression of the standard expression for reversible first-order reactions.…”