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 \(\mathrm{C}_{22}\mathrm{H}_{24}\mathrm{O}\), 304. \(MR_D\): found 92.5; calculated 91.6.

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).