JPH0237919B2 - KAPURORAKUTON NOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new method for producing caprolactone (6- or ε-caprolactone), and more specifically, the production of caprolactone by reacting adipaldehyde acid with hydrogen in the gas phase in the presence of a catalyst containing copper as an essential component. It is about the method. Caprolactone is a useful substance as a raw material for polymers and an intermediate in organic synthesis, but the conventionally widely used production method is the so-called BayerVilliger reaction, in which cyclohexanone is reacted with an organic peracid such as peracetic acid. be. However, this method has the following drawbacks.
In other words, the peracid used as a raw material is dangerous, difficult to handle, and expensive, and it must be used in large quantities for this reaction.As a result, a large amount of carboxylic acid derived from the peracid is produced as a by-product. There was also the disadvantage of being born alive. Therefore, there has been a strong desire to develop a new method for producing caprolactone that does not have these drawbacks. In view of the above circumstances, the present inventors have conducted intensive studies and found that when adipaldehyde acid, which is easily obtained by oxygen oxidation of cyclohexanone, is reacted with hydrogen in the gas phase in the presence of a catalyst containing copper as an essential component, It was discovered that the hydrogenation reaction and cyclization reaction proceed simultaneously in the step, producing caprolactone in good yield, and the method of the present invention was achieved. That is, the method of the present invention consists in a novel method for producing caprolactone that uses only cyclohexanone, oxygen, and hydrogen as raw materials, does not require the peracid of the conventional method, and does not produce a large amount of carboxylic acid as a by-product. The present invention will be explained in detail below. The catalyst used in the method of the invention contains copper as an essential element. The starting material that provides the copper component in the catalyst can be selected from among many types. For example, copper nitrate, copper oxide, copper chloride,
Copper hydroxide etc. can be used. However, when copper is used alone, there are problems such as excessive reduction of the catalyst, deactivation due to sintering, etc., and a decrease in selectivity due to an increase in low-boiling decomposition products.
More preferably, it is used as a multi-component catalyst of copper and other elements. Elements that can be combined with copper include, for example, magnesium as an element of the periodic table group,
Calcium, barium, zinc, cadmium, etc.
Group elements include aluminum, rare earth elements, etc.
Group elements include silicon, germanium, tin, lead,
Titanium, zirconium, hafnium, vanadium, niobium, tantalum, antimony, bismuth as group V elements, chromium, molybdenum, tungsten as group elements, manganese, rhenium as group elements, iron, cobalt, etc. as group elements However, chromium, manganese, barium,
Zinc etc. are preferred. The ratio of copper to other elements is preferably 1:0.02 to 1.5 in atomic ratio. By using these elements in combination, the yield of caprolactone is improved and the life of the catalyst is extended. Although the catalyst exhibits excellent activity without a carrier, it can also be used supported on a suitable carrier. That is, it can be formulated to contain 10% to 90% of the total active ingredient. As the carrier, diatomaceous earth, pumice, alumina, silica, titania, etc. can be used. The catalyst can also be used after being pretreated with hydrogen before the reaction. However, the catalyst undergoes pretreatment with hydrogen or reduction during the reaction, and in some cases becomes partially in the state of metallic copper, and although the activity remains, the yield of the desired product, caprolactone, decreases. Although the true valence state of copper during the reaction is unknown, it is preferable to avoid catalysts with compositions that apparently produce a large amount of metallic copper. The reaction is preferably carried out in the gas phase to avoid copper elution. The reaction temperature is suitably 150 to 400°C, more preferably 200 to 300°C. Normal pressure is sufficient for the reaction pressure, but the reaction can also be carried out under slightly reduced pressure or increased pressure. The partial pressure of hydrogen during the reaction is important not only for being consumed by the reaction but also for maintaining the activity of the catalyst, and is preferably maintained at about 0.05 to 3 atm. The coexistence of water vapor during the reaction has the effect of improving the yield and maintaining the activity of the catalyst. The amount of water vapor added is preferably about 0.5 to 200 moles, more preferably about 3 to 50 moles, based on adipaldehyde acid. The space velocity of gas is 100 ~
It is carried out at about 10,000 hr ^-1 , more preferably about 500 to 5,000 hr ^-1 . The reaction product is cooled and collected, and caprolactone is recovered by known methods such as distillation and extraction.
Incidentally, 6-hydroxycaproic acid, which is a ring-opening product, and its oligomer by-product are usually observed, but these can be converted into caprolactone by a known method. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Incidentally, the conversion rate of adipaldehyde acid, the selectivity of 6-caprolactone, the selectivity of 6-hydroxycaproic acid and its oligomer, and the yield of 6-caprolactone are defined by the following formula.

[Table] Example 1 [Preparation of catalyst] 16 to 24 meshes of γ-alumina (manufactured by Rhône-Poulenc, SCM250) was impregnated and supported with a copper nitrate aqueous solution, and the copper content was prepared to be 10% by weight. Thereafter, it was calcined in air at 500°C for 3 hours, and further reduced in a hydrogen stream at 160°C for 3 hours to prepare a catalyst. [Reaction] Fill a reaction tube with 1.8 ml of the catalyst prepared by the above method, and add a mixed gas of adipaldehyde acid, water vapor, and hydrogen (volume composition ratio = 1.6:32:664) at a space velocity of 1.8 ml.
It was supplied to the reaction tube at 2000 hr ^-1 and the reaction was carried out at 280°C. When the liquid phase obtained by cooling and collecting the product one hour after the start of the reaction was quantitatively analyzed by gas chromatography, the yield of 6-caprolactone was found to be
It was 3.3%. Example 2 Copper-chromium commercially available catalyst, JGC N201 (atomic ratio;
Fill a reaction tube with 1.8 ml of copper:chromium:manganese=1:1.27:0.08 (manufactured by JGC Chemical Co., Ltd.), perform hydrogen reduction at 160°C for 3 hours, and then add adipaldehyde under the same conditions as in Example 1. A mixed gas of acid-steam-hydrogen was supplied to carry out the reaction. The reaction results 2 hours after the start of the reaction were as follows. Conversion rate of adipaldehyde acid 100% Selectivity of 6-caprolactone 60.5% Selectivity of 6-hydroxycaproic acid and its oligomer 4.3% Examples 3 to 5 Examples except that the catalysts shown in Table 1 below were used. A reaction similar to 2 was conducted under the same conditions. The results are shown in Table-1.

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Claims (1)

[Claims] 1. A method for producing caprolactone, which comprises reacting adipaldehyde acid with hydrogen in the gas phase in the presence of a catalyst containing copper as an essential component.