CHEMISTRY

Academician A. V. TOPCHIEV and V. L. VAISER

HYDROGENATION OF CERTAIN UNSYMMETRICAL DIARYLETHANES

In studies ((^{1-5})) on the alkylation with acetylene of toluene, isopropylbenzene, diisopropylbenzene, phenol, cresol, and (\beta)-naphthol using the catalyst (\mathrm{H_3PO_4 \cdot BF_3}), individual compounds were obtained—diarylethanes of the general formula

[
\mathrm{Ar{-}CH{-}Ar}
]
[
\phantom{\mathrm{Ar{-}}}\big|
]
[
\mathrm{CH_3}
]

or oxydiarylethanes

[
\mathrm{HO{-}Ar{-}CH{-}Ar{-}OH}
]
[
\phantom{\mathrm{HO{-}Ar{-}}}\big|
]
[
\mathrm{CH_3}.
]

We subjected these compounds to hydrogenation in an apparatus of the Musaev—Gal’pern system at elevated temperatures and pressure, with an industrial catalyst, Ni on kieselguhr.

Hydrogenation of ethylideneditolyl (EDT)

[
\mathrm{H_3C{-}\langle C_6H_4\rangle{-}CH{-}\langle C_6H_4\rangle{-}CH_3}
]
[
\phantom{\mathrm{H_3C{-}\langle C_6H_4\rangle{-}}}\big|
]
[
\mathrm{CH_3}
]

Into the autoclave were placed 20 g of EDT and 5 g of catalyst; the temperature was (250—300^\circ) and the pressure (100—150) atm.

After 8 hours the product was drained from the autoclave, filtered, washed with alkali and water, dried with calcium chloride, and distilled under vacuum. A clear oily liquid was obtained, b.p. (108—110^\circ/2) mm, (d_4^{20}\ 0.8502), (n_D^{20}\ 1.4800). Molecular weight found 216; calculated for (\mathrm{C_{16}H_{30}}) 222. (MR_D) found 72.8, calculated 71.7.

The compound may be identified as 1,1-(4,4-dimethyl)di-cyclohexylethane

[
\mathrm{H_3C{-}\langle C_6H_{10}\rangle{-}CH{-}\langle C_6H_{10}\rangle{-}CH_3}
]
[
\phantom{\mathrm{H_3C{-}\langle C_6H_{10}\rangle{-}}}\big|
]
[
\mathrm{CH_3}
]

Hydrogenation of ethylidenediisopropylbenzene

[
\mathrm{u{-}C_3H_7{-}\langle C_6H_4\rangle{-}CH{-}\langle C_6H_4\rangle{-}u{-}C_3H_7}
]
[
\phantom{\mathrm{u{-}C_3H_7{-}\langle C_6H_4\rangle{-}}}\big|
]
[
\mathrm{CH_3}
]

It was carried out under conditions analogous to the hydrogenation of EDT. The product obtained was an oily clear liquid, b.p. (160—162^\circ/4) mm, (d_4^{20}\ 0.8989), (n_D^{20}\ 1.4898). Viscosity at (50^\circ) 20.4 cs, at (100^\circ) 3.9 cs. Molecular weight found 275; 279; calculated for (\mathrm{C_{20}H_{38}}) 278. (MR_D) found 90.0; calculated 90.2.

The compound may be identified as 1,1-(4,4′-diisopropyl)dicyclohexylethane

[
\ce{n-C3H7-[cyclohexyl(H)]-CH(CH3)-[cyclohexyl(H)]-n-C3H7}
]

Hydrogenation of ethylidenediisopropylbenzene

[
\ce{n-C3H7-C6H3(n-C3H7)-CH(CH3)-C6H3(n-C3H7)-n-C3H7}
]

As a result of hydrogenation under conditions analogous to the preceding ones, a product was obtained—a clear viscous liquid, b.p. (177\text{–}179^\circ/1) mm, (n_D^{20}) 1.4980. Molecular weight found 356; calculated for (\ce{C26H50}) 362.

The compound may be identified as 1,1-(2,2′,4,4′-tetraisopropyl)dicyclohexylethane

[
\ce{n-C3H7-[cyclohexyl(H)(n-C3H7)]-CH(CH3)-[cyclohexyl(H)(n-C3H7)]-n-C3H7}
]

Hydrogenation of phenol alkylate

[
\ce{HO-C6H4-CH(CH3)-C6H4-OH}
]

It was carried out at a temperature of (280^\circ), pressure of 100 atm, with Ni on kieselguhr catalyst in an amount of 20% of the alkylate; the solvent was (n)-heptane. Hydrogenation was continued for 10 hours until a negative test for the formalite reaction was obtained. The purified product—the hydrogenate—was a clear viscous liquid: (n_D^{20}) 1.5065, (d_4^{20}) 1.007, b.p. (160\text{–}165^\circ/6) mm. Molecular weight found 236; 232; calculated for (\ce{C14H26O2}) 226.

(MR_D) found 66.5; calculated 65.5. The compound may be identified as 1,1-(4,4′-dioxy)dicyclohexylethane

[
\ce{HO-[cyclohexyl(H)]-CH(CH3)-[cyclohexyl(H)]-OH}
]

Hydrogenation of ethylidene-di-(o)-cresol

[
\ce{HO-C6H3(CH3)-CH(CH3)-C6H3(CH3)-OH}
]

was carried out in the same way as for the phenol alkylate. A clear viscous liquid was obtained. B.p. (160\text{–}165^\circ/3) mm, (n_D^{20}) 1.4815, (d_4^{20}) 0.9620. Molecular weight found 260; calculated for (\ce{C16H30O2}) 254. (MR_D) found 75.5; calculated 74.8.

The compound may be identified as 1,1-(4,4′-dioxy-3,3′-dimethyl)dicyclohexylethane

[
\ce{HO-[cyclohexyl(H)(CH3)]-CH(CH3)-[cyclohexyl(H)(CH3)]-OH}
]

Hydrogenation of β-Naphthol Alkylate

Hydrogenation was carried out under conditions analogous to the preceding ones. A transparent viscous liquid was obtained. B.p. 178–179°/1 mm, (n_D^{20}) 1.5151, (d_4^{20}) 0.9800. Molecular weight: found 308; 302; calculated for (\mathrm{C}{22}\mathrm{H}), 304. (MR_D): found 92.5; calculated 91.6.}\mathrm{O

The resulting hydrocompound may be identified as di(tetrahydronaphtho)pyran:

The hydrocompounds obtained for the first time by this method may serve as a basis for an in-depth theoretical and practical study of the hydrogenation reaction of diarylethanes.

Moscow Petroleum Institute
named after I. M. Gubkin

Received
29 V 1958

References

1. V. L. Vaiser, DAN, 87, No. 4 (1952).
2. V. L. Vaiser, A. M. Polikarpova, DAN, 84, No. 1 (1952).
3. V. L. Vaiser, DAN, 103, No. 5 (1955).
4. V. L. Vaiser, A. M. Polikarpova, DAN, 108, No. 3 (1956).
5. V. L. Vaiser, DAN, 115, No. 1 (1957).