1,2-diphenylethane

Gas chromatography on a 200 cm. by 0.6 cm. column packed with 10% Apiezon L on Chromosorb W (AW, DMCS) using a flame-detector instrument, at a 40 ml./minute helium carrier gas flow rate, gives a trace peak at 9.9 minutes (diphenylmethane), a major peak at 11.7 minutes (1,1-diphenylethane), and a trace peak at 15.4 minutes (1.1-diphenylethanol) when the oven is held at 190° for 10 minutes and then programmed at 10°/minute to 290°. 

In addition to the present method, other procedures have been reported for the synthesis of 1,1-diphenylethane.5-7... 

A possible mechanism of oxidation of methylene groups to carbonyl groups involves autoxidation (oxidation by molecular oxygen) at the benzylic position. Autoxidation of arylalkanes is a facile reaction with low activation energies for example, 6.0 kcal/mole for 1,1-diphenylethane and 13.3 kcal/mole for toluene. ... 

But the same 1, 1-diphenylethylene when reacted in the presence of fluorohectorite gives oxidized products, 1, 1-diphenylethane and benzophenone. 

N 15.47% crysts (from acet ac), mp 157° was prepd by addg 1,1-diphenylethane to nitric acid (d 1-35) St coned sulfuric acid at 30—35° (Ref 6). No expl props were reported... 

Analogous methyl azidoformate forms with norbornene a thermal unstable triazoline.251 The decomposition products are 40% aziridine and 55% imide. Furthermore it has been observed that the rate of nitrogen evolution of the triazoline from methyl azidoformate increases threefold when triglyme and 20-fold when dimethyl sulfoxide are substituted for 1,1-diphenylethane as solvents. This fact supports a betaine intermediate in the thermal decomposition reaction. The triazoline from 2,4-dinitrophenyl azide and norbornene could just be isolated, but from picryl azide only the aziridine was obtained.252-254 Nevertheless, the high negative value of the activation entropy (—33.4 eu) indicates a similar cyclic transition state for both reactions. 

In highly dilute mixtures of bibenzyl in tetralin (llj), (one part bibenzyl in 200-1000 parts tetralin) 1,1-diphenylethane is formed at a rate independent of dilution and roughly one-sixth of the rate found in pure bibenzyl. This implies that free-radical concentrations are independent of the concentration of free-radical initiators in sufficiently pure tetralin. 

When treated with a mixture of Ph3Bi and /-BuOOH in CCI4 or toluene, dibenzyl is oxidized to benzil (Equation (100)). The active oxidant is assumed to be an 02-eoordinated bismuthane complex (Ph3Bi-02).169 Triphenylmethane and 1,1-diphenylethane are oxidized by this complex to the corresponding hydroperoxides. 

The transalkylation and isomerization reactions can be satisfactorily explained by the Streitwieser mechanism( ). This mechanism proposes a 1,1-diphenylethane-type intermediate. For example, para-diethylbenzene. (Figure 3) Such an intermolecular mechanism is consistent with the experimental data and does not require the assumption of a sequence of intramolecular 1,2 shifts. The decay of the polyethylbenzenes towards equilibrium is consecutive and not concurrent. The catalyst seems to be associated with the most basic center and when it reaches steady-state, the catalyst transfers to the next most basic one. There is also a concurrent intramolecular isomerization such as 1,2,4 triethylbenzene going to 1,3,5 triethylbenzene. There is hence a movement towards isomer equilibrium as well as product equilibrium. 

Commercially, the best way to prepare 1,1-DPE is probably to react styrene and benzene with one another and then to dehydrogenate the resulting 1,1-diphenylethane to 1,1-diphenylethylene. This has been developed to the pilot plant stage in BASF [7]. 

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