JP3089026B2 - Regeneration method of allyl acetate production catalyst - Google Patents

Description

The present invention relates to a method for regenerating a palladium-supported catalyst, and particularly to a method for producing allyl acetate from propylene, acetic acid and oxygen in the gas phase using a palladium-supported catalyst. And a method for regenerating a palladium-supported catalyst having reduced activity during use.

[Conventional technology]

Methods for producing allyl acetate by reacting propylene, oxygen and acetic acid in the gas phase using a palladium catalyst are known (for example, JP-B-44-29046, JP-B-47-12335,
JP-B-47-38415, JP-B-48-10761, JP-B-50-5685
etc〕. These methods use palladium as the main catalyst and at least one of alkali metals or alkaline earth metals and at least one of gold, copper, molybdenum, cadmium, lead, vanadium, bismuth, chromium, tungsten, manganese, iron, ruthenium and rhenium. Using metal as co-catalyst,
These catalyst components, usually alumina, silica, activated carbon,
It is carried out using a catalyst prepared by being supported on pumice, titanium oxide or the like.

However, such a catalytic reaction generally has a problem in that the activity gradually decreases as the reaction time becomes longer, and the amount of allyl acetate produced decreases.

[Problem to be solved by the present invention]

In the above-mentioned production method, a catalyst in which palladium is supported as a main catalyst on the above-described carrier is used, but the catalytic activity of the palladium-supported catalyst gradually decreases with the reaction time as the reaction continues for a long time, and Since the selectivity of allyl acetate also decreases, the yield of allyl acetate decreases. In view of the above circumstances, the present inventors have aimed to provide an effective and simple method for regenerating a catalyst in the production of allyl acetate.

[Means and Actions for Solving the Problems]

The present inventors have conducted intensive studies to provide a method for effectively regenerating a palladium-supported catalyst used for producing allyl acetate from propylene, acetic acid, and oxygen by a gas phase reaction. The palladium-supported catalyst used is washed in pure water or a solvent consisting of an organic solvent having a boiling point of 70 ° C. or more and a carbon number of 6 or less under normal pressure, and then dried, and then, if necessary, an alkali metal or alkaline earth. The present inventors have found that a catalyst whose activity has been reduced by supporting a metal acetate is regenerated and completed the present invention.

 Hereinafter, the present invention will be described in detail.

In the present invention, first, the palladium-supported catalyst used in the method for producing allyl acetate by reacting allyl acetate in the gas phase from propylene, acetic acid, and oxygen is washed with an appropriate solution.

The solvent used for washing is preferably a solvent capable of removing the Hartz covering the surface of palladium, the resinized material, and the alkali metal and alkaline earth metal acetate without any change in the form of palladium. Or an organic solvent having a boiling point of 70 ° C. or more and having 6 or less carbon atoms, for example, acetic acid, organic acids such as propionic acid, or ethyl acetate;
Esters such as butyl acetate and isopropyl acetate and alcohols such as ethanol, propanol, isopropyl alcohol and butanol are used, and washing with pure water is particularly preferable.

As a washing method, there are a distribution method in which a column is filled with a catalyst and a solution is passed through the column for washing, and a batch method in which a solution and a catalyst are put in a beaker and the mixture is stirred and washed.

As the temperature for performing the washing, there is an effect at 5 ° C to 70 ° C,
Particularly, washing at 15 to 40 ° C is preferred. If the temperature is lower than 5 ° C., the cleaning effect on the catalyst surface is insufficient, and if the temperature exceeds 70 ° C., the form of palladium is probably deteriorated.
The increase in the active surface of palladium metal, which is determined by measuring the amount of chemisorption, is small, and the activity recovery is low. On the other hand, if the temperature exceeds 70 ° C., operation is disadvantageous.

Next, after drying the washed catalyst, an alkali metal or alkaline earth metal acetate is supported, and further dried. In this case, the supported amount is preferably 1 to 30% by weight, particularly preferably 5 to 15% by weight. As the alkali metal or alkaline earth metal to be supported, salts such as sodium, potassium, rubidium, cesium, calcium, strontium, barium and the like are usually used.

Hot air drying, vacuum drying, natural drying, and the like are generally used as methods for drying the washed catalyst and drying after supporting an alkali metal or alkaline earth metal acetate.

In the method of the present invention, when propylene, acetic acid and oxygen are reacted to produce allyl acetate, the reaction temperature is
It is practically advantageous that the temperature is 100 to 200 ° C, preferably 140 to 170 ° C. It is practically advantageous that the reaction pressure is from normal pressure to 30 atm from the viewpoint of equipment, but more preferably from 2 to 10 atm.
Atmospheric pressure.

The gas supplied to the reaction system is substantially propylene,
Acetic acid, oxygen and diluent gases. Propylene is 5 to 50% by volume, preferably 10 to 10% by volume, based on the total amount of the supplied gas.
Acetic acid in an amount of 5 to 20% by volume, preferably 6 to 10% by volume, and oxygen in an amount of 40% by volume.
To 15% by volume, preferably 5 to 10% by volume, respectively. In addition, the reaction may be performed in the presence of an appropriate amount of water from the viewpoint of extending the catalyst life.

〔Example〕

 Hereinafter, the present invention will be further described with reference to examples.

Example 1 200 ml of the catalyst used in the reaction was placed in a beaker, 200 ml of pure water was added thereto, and the mixture was stirred and washed at room temperature. This is repeated three times, the catalyst water is drained, and hot air drying is performed at 110 ° C. for 20 hours using a dryer. Next, 3 g of potassium acetate is taken, converted into an aqueous solution, and then supported by impregnating the above-mentioned dry catalyst. This is dried with a hot air drier at 110 ° C. for 4 hours to obtain a regenerated catalyst. This catalyst was charged into a reaction tube and propylene 30
%, Oxygen 7%, acetic acid 10.0%, nitrogen 53.0%
The reaction was carried out under the conditions of a reaction pressure of 5 kg / cm ² G and a reaction temperature of 160 ° C. The results are shown in Table 1.

Example 2 A catalyst was regenerated in the same manner as in Example 1 except that ethyl acetate was used instead of water, and an allyl acetate synthesis reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1.

Example 3 A catalyst was regenerated in the same manner as in Example 1 except that acetic acid was used instead of water, and an allyl acetate synthesis reaction was performed under the same conditions as in Example 1. The results are shown in Table 1.

Example 4 A catalyst was regenerated in the same manner as in Example 1 except that the temperature of water was changed to 5 ° C., and an allyl acetate synthesis reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1.

Example 5 A catalyst was regenerated in the same manner as in Example 1 except that the temperature of water was changed to 70 ° C., and an allyl acetate synthesis reaction was carried out under the same conditions as in Example 1. The results are shown in Table 1.

Example 6 The catalyst was regenerated in the same manner as in Example 1 except that rubidium acetate was used instead of potassium acetate, and an allyl acetate synthesis reaction was performed under the same conditions as in Example 1. The results are shown in Table 1.

Example 7 The catalyst was regenerated in the same manner as in Example 1 except that strontium acetate was used instead of potassium acetate, and an allyl acetate synthesis reaction was performed under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 1 After the catalyst used for the reaction was once dried, an allyl acetate synthesis reaction was performed under the same conditions as in Example 1. The results are shown in Table 1.

[Effect of the Invention] According to the method for regenerating a palladium-supported catalyst of the present invention, the palladium catalyst used for the production of allyl acetate can be effectively regenerated, and a highly active catalyst can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Hiroshi Nishino, Inventor 2 Oita, Oita City, Oita Prefecture Showa Denko KK Oita Factory (56) References JP-A-51-119693 (JP, A) JP-A Heihei 2-160048 (JP, A) JP 42-20480 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 21/00-38/00 C07C 69/155

Claims (2)

(57) [Claims] 1. A reaction for obtaining allyl acetate by reacting acetic acid, propylene and oxygen in the gas phase using a palladium-supported catalyst, wherein the catalyst used in the reaction has a boiling point of 70 ° C. or higher under water or normal pressure and A method for regenerating an allyl acetate production catalyst, comprising washing with an organic solvent having 6 or less carbon atoms. 2. The method according to claim 1, wherein the washed catalyst is loaded with an alkali metal or alkaline earth metal acetate.