CS239665B1 - Process for the preparation of a mixture of allylbenzene and 3-fanylpropanal - Google Patents

Abstract

The invention relates to the preparation of a mixture of allylbenzene and 3-phenylpropanal by catalytic decomposition of 4-phenyl-1,3-dioxane over catalysts based on ash at a temperature of 240 to 300 C. 3-Phenylpropanal is used in the perfumery and pharmaceutical industries. Allylbenzene is an intermediate for the production of a number of pharmaceutical preparations.

Description

The invention relates to a process for the preparation of a mixture of allylbenzene and 3-phenylpropanal. 3-Phenylpropanal is mainly used in the perfumery and pharmaceutical industries. Allylbenzene finds use as an intermediate for the synthesis of pharmaceutical preparations.

Allylbenzene is produced predominantly by the Friedel-Crafte reaction from benzene and allyl alcohol, as described, for example, in Huson and Sager, J. Amer. Chem. Soc. 1957 (1926), Simons and Arohen, J. Amer. Chem. Soc. 1521 (1939), Kenna and Sowy in J. Amer. Chem.

Soc. £ 2, 470 (1937), or by reaction of phenylmagnesium bromide and alkyl bromide as described by Ochiasi Masahito and Arimoto Masao in Tetrahedron Lett. 22, 4491 (1981).

These reactions are difficult, result in a large amount of solid waste, and are also demanding on equipment. Hydroformylation of styrene, for example according to French patent 2,015,475, results in a mixture of 6 and 6-phenylpropanals, reap. of the corresponding alcohols, requires work at high pressure and uses expensive catalysts.

The disadvantages of the processes described above for the production of allylbenzene and 3-phenylpropanal are virtually eliminated by the process according to the invention, which consists in subjecting 4-phenyl-1,3-dioxane to catalytic cleavage on copper, zinc, alumina and aluminum oxide catalysts. or mixtures thereof at 240-300 ° C. The production of allylbenzene and 3-phenylpropanal directly from 4-phenyl-1,3-dioxane has the advantage that it is one-stage. The 3-phenylpropanal is isolated from the mixture by distillation.

The invention is illustrated by the following Examples.

Example l

The reactor consisted of a glass tube (7 x 450 mm) placed in an air jacket heated by an electric spiral. The temperature was controlled by the Fe-Ko control thermocouple with the Term 80 controller, a specific thermocouple (also Fe-Ko) was placed on the reactor wall at the center of the catalyst bed. The temperature varied within + 1 ° C.

A layer of glass beads was placed over the catalyst bed to evaporate and preheat 4-phenyl-1,3-dioxane. This was injected into the reactor by a linear feeder. Prior to this, catalyst reduction was performed at 220 ° C, not for 1 hour with the mixtures. 90% nitrogen and 10% hydrogen, then 1 hour with a mixture of 80% nitrogen and 20% hydrogen and finally 1 hour with pure hydrogen at a total gas flow rate of 240 ml / min.

Thereafter, the temperature was raised to 260 ° C over 15 minutes at which the catalyst was reduced for 30 minutes. Then, 4-phenyl-1,3-dioxane was started and by spraying usually a flow rate

0.9375 ml / hr. The reaction mixture was collected in a freezer. After the regime had stabilized, samples were taken and analyzed by gas chromatography.

Using a Leuna 1950 catalyst containing CuO, ZnO and AljOj, a 4-phenyl-1,3-dioxane cleavage at 260 ° C and a W / F (2.88) (βχ ^ τ / δρΐ) / · ¹¹ cleavage was obtained, containing 42.9 wt. % unreacted 4-phenyl-1,3-dioxane, 25.9 wt. 3-phenyl-propenel,

8.3 wt. % Of 3-phenyl-1-propanol and 22.9 wt. allylbenzene.

Example 2

Under the same conditions as in Example 1, a BASF-Ϊ1154 catalyst containing a currency (catalyst composition not reported by the manufacturer) was used for the cleavage. The reaction mixture contained 48.7 wt. % unreacted 4-phenyl-1,3-dioxane, 20 wt. % 3-phenylpropanal, 9.4 wt.

3-phenyl-1-propanol and 21.9 wt. allylbenzene.

Example 3

Under the same conditions as in Example 1, cleavage catalyst (Meines de Melle) was used for cleavage. The reaction mixture contained 52.8 wt. % unreacted 4-phenyl-1,3-dioxane, 22.5 wt. 3-phenylpropanal, 5 wt. % 3-phenyl-1-propanol, 3.5 wt. % allylbenzene and 16.2 wt. styrene.

Example 1 a d 4

Under the same conditions as in Example 1, a Harshaw Cu 0203 catalyst containing 80 wt. CuO and 20 wt. CrgO-j. The yield of allylbenzene was 61% by weight, 10% by weight. % Of 3-phenylpropanal and 28 wt. 3-phenylpropanol.

Example 5

Under the same conditions as in Example 1 was used for the cleavage of BASF catalyst - 0 to 31, consisting of CuO, ZnO, ALJO ^ i ^{< 'r} 2 ° 3 * allylbenzene obtained in 99% wt. 0.5 wt. 3-phenylpropanal and 0.5% 3-phenylpropanol.

Claims (1)

P S E I N OF THE INVENTION Process for the preparation of a mixture of allylbenzene and 3-phenylpropenel, characterized in that 4-phenyl-1,3-dioxane is subjected to catalytic cleavage on catalysts based on cuprous, zinc, alumina and chromium or mixtures thereof at a temperature of 240-300 °. C.