JPS6239135B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing cyclohexadiene. Specifically, the present invention relates to improvement of a catalyst for producing 1,3-cyclohexadiene from cyclohexene oxide. 1,3-Cyclohexadiene is a very useful compound as a compound having a plurality of substituents on a six-membered carbon ring and as a synthetic intermediate for the Diers-Alder reaction. 1,3-Cyclohexadiene is the dehydrohalogenation of 1,3-dihalogencyclohexane, 2-
Deacetic acid of cyclohexenyl acetate, 1,4-
It is known that it can be produced by methods such as dehydration of cyclohexanediol, but these methods have drawbacks such as the production of many by-products and the difficulty in obtaining raw materials, so none of these methods can be called industrial production methods. On the other hand, the present inventors previously reported that 1,3-cyclohexadiene is produced when cyclohexene oxide is brought into contact with alumina, titania, zirconia, etc. in the gas phase. [Biurethane of the Chemical Society of Japan
(Refer to Bull.Chem.Soc.Japan) Volume 49, Page 563, 1976]. However, even this method was still insufficient in that the conversion rate of cyclohexene oxide was low. In view of these circumstances, the present inventors conducted extensive research aimed at improving catalysts for producing 1,3-cyclohexadiene from cyclohexene oxide, and arrived at the present invention. That is, the gist of the present invention resides in a method for producing 1,3-cyclohexadiene, which is characterized in that cyclohexene oxide is brought into contact with silica-titania or silica-titania-magnesia in a liquid phase. The present invention will be explained in detail below. In the method of the present invention, silica-titania or silica-titania-magnesia is used as a catalyst.
Of course, there is no harm in using both together. Silica-titania and silica-titania-magnesia produced by known methods can be used. Silica-titania can be produced, for example, by coprecipitation from a solution of ethyl orthosilicate and titanium tetrachloride, followed by firing. Silica-titania-magnesia can be produced, for example, by kneading and firing the silica-titania and magnesium hydroxide. The atomic ratio of silicon to titanium in silica-titania is usually 5-95:5-95. The atomic ratio of silicon, titanium, and magnesium in silica-titania-magnesia is usually 5 to 5.
The ratio is 90:5 to 90:5 to 90. The contact between cyclohexene oxide and the catalyst is usually carried out at 50 to 250°C, preferably 70 to 150°C.
At this time, an inert solvent such as benzene, toluene,
Hydrocarbons such as xylene may also be present. The reaction can be carried out either continuously or batchwise. In the case of a batch method, cyclohexene oxide, a catalyst in an amount of 0.01 to 1 times the weight of cyclohexene oxide, and an inert solvent as necessary may be placed in a reactor, and the reaction may be carried out at the above-mentioned temperature with stirring. The reaction time varies depending on the reaction conditions and desired reaction rate, but is usually 0.2 to 10 hours. The reaction is preferably carried out in such a way that the produced water is continuously distilled off. Separation of 1,3-cyclohexadiene from the reaction product is carried out by conventional methods. That is, if necessary, after removing the catalyst by filtration or centrifugation, 1,3-cyclohexadiene can be separated by distillation. According to the method of the present invention, the conversion rate of cyclohexene oxide is very high and the yield of the target product is also good. Also, the reaction conditions are mild and the amount of undesirable by-products is low. In addition, since the reaction can be carried out using a liquid phase batch method, in the case of relatively small-scale production,
Particularly advantageous. EXAMPLES The present invention will be explained in more detail with reference to Examples and Reference Examples below, but the present invention is not limited by the Examples unless it exceeds the gist thereof. Reference Example 1 Production of silica-titania catalyst Equimolar water of ethyl orthosilicate (104.7 g, 0.5 mol) and titanium tetrachloride (95.3 g, 0.5 mol) 3
81.2 ml of 28% ammonia water was added to the solution to precipitate. After aging the reaction on a water bath for 1 h,
The precipitate was collected by filtration, washed with distilled water until no chlorine ions were detected, dried at 100℃ for 20 hours,
Calcined at ℃. Reference Example 2 Production of silica-titania-magnesia catalyst 100 g of silica-titania produced in Reference Example 1 and 41.7 g of magnesium hydroxide were kneaded with an appropriate amount of water for 2 hours, dried at 120°C for 1 hour, and kneaded at 500°C. Fired. Magnesium hydroxide was prepared in the same manner as in Reference Example 1 by hydrolyzing magnesium chloride with dilute ammonia water, washing, and drying. Reference Example 3 Manufacture of Catalyst of Comparative Example (i) Silica-Alumina Catalyst Commercially available silica-alumina [Al ₂ O ₃ content: 15% by weight] was calcined at 500°C. (ii) Lithium perchlorate catalyst Commercially available LiClO ₄ .3H ₂ O was dried at 120°C for 3 days. (iii) Silica-sulfuric acid catalyst 10g of granular silica gel was dissolved in 0.5M sulfuric acid aqueous solution12
ml, dried and calcined at 150°C. (iv) Iron sulfate () and Etzkel sulfate catalyst The respective heptahydrate salts were calcined at 500°C or 350°C. (v) Solid phosphoric acid catalyst A commercially available solid phosphoric acid catalyst was calcined at 300°C. (vi) Titania-zirconia catalyst An aqueous solution containing equimolar amounts of titanium tetrachloride and zirconium oxide dichloride and an excess amount of urea is heated on a boiling water bath, the precipitate is filtered,
The titanic acid-zirconium hydroxide [H ₄ TiO ₄ −Zr(OH) ₄ ] obtained by washing with distilled water until no chlorine ions are detected and drying at 110°C,
Pyrolyzed at 500℃. (vii) Alumina catalyst Four types of commercially available alumina catalysts were calcined at 500℃,
They were labeled A to D, respectively. All catalysts are ground to less than 100 mesh;
Heat treatment was performed in the air for 3 hours. Examples 1 to 2 and Comparative Examples 1 to 11 As cyclohexene oxide, a commercially available product was used as it was, and as toluene, a commercially available product was used, which had been distilled after adding metallic sodium in advance. The reaction consists of 0.5 ml of cyclohexene oxide, 2.5
ml of toluene and the amount of catalyst shown in Table 1 were placed in a reaction vessel equipped with a magnetic stirrer and heated to 108°C. After the reaction time shown in Table 1 had elapsed, a portion was taken out and the product was analyzed by gas chromatography. Table 1 shows the results.
It was shown to. 【table】

Claims (1)

[Claims] 1. A method for producing 1,3-cyclohexadiene, which comprises contacting cyclohexene oxide with silica-titania or silica-titania-magnesia in a liquid phase.