JP2852950B2 - Regeneration method of olefin hydration catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to an important alcohol as various chemical raw materials,
The present invention relates to a method for regenerating a catalyst when produced by hydration of an olefin.

(Prior art) When hydration of an olefin is performed in a liquid phase using zeolite as a catalyst, the activity of the catalyst gradually decreases as the reaction progresses. As a method for regenerating the catalyst whose activity has been reduced, a method of regenerating in the liquid phase using an oxidizing agent such as hydrogen peroxide, ozone, an organic peracid, or nitric acid (see JP-A-61-234945), a zeolite Is exchanged with an alkali metal ion in advance, and then contacted with a gas containing molecular oxygen at 200 to 600 ° C., and the alkali metal ion is removed by re-exchange (see JP-A-61-234946). Etc. have been proposed.

(Problems to be Solved by the Invention) Among the prior arts, the regeneration method using hydrogen peroxide, ozone, etc. in the method using an oxidizing agent in the liquid phase, when the activity of the catalyst is certainly small, Although the method is effective at a high rate, it is difficult to completely restore the activity when the activity is significantly reduced. Such a drawback is particularly problematic when the catalyst is used in a completely mixed slurry system and is periodically extracted at a certain ratio and regenerated, because there is always a certain ratio of the catalyst remaining without being regenerated for a long period of time.

In addition, the method of exchanging with alkali metal ions in advance and then contacting with molecular oxygen involves a long regeneration step, and further includes a liquid phase treatment and a gas phase treatment. There was an extremely complicated problem.

(Means for Solving the Problems) The present inventors have conducted intensive studies on a method capable of realizing a high regeneration rate even in the regeneration of a catalyst whose activity is significantly reduced, and as a result, the catalyst is brought into contact with an oxidizing agent in a conventional liquid phase. After regeneration, they have found that the activity can be almost completely recovered by contact with an aqueous solution of an inorganic alkali and further contact with an inorganic acid, thereby completing the present invention.

That is, in the present invention, in regenerating the zeolite catalyst subjected to the olefin hydration reaction in the liquid phase, after contacting the zeolite with the oxidizing agent in the liquid phase, and then contact with an aqueous inorganic alkali solution, furthermore, with the inorganic acid This is a method for regenerating an olefin hydration catalyst, characterized in that the catalyst is connected.

The cause of the decrease in zeolite activity in this reaction system is not clearly understood, and it is not clear why the alkali aqueous treatment is effective. However, the following may be considered.

In the hydration reaction of an olefin in a liquid phase, an acid-type zeolite is usually used, but on an acid catalyst,
An olefin polymerization reaction and a side reaction such as formation of ether, which is a successive product of the produced alcohol, also occur at the same time. These high-boiling products cause pores of the zeolite to be clogged and cause a decrease in activity. It is considered that the regeneration with the oxidizing agent in the liquid phase removes this high-boiling substance by oxidation. On the other hand, when a catalyst that has been used for a long period of time and is significantly deteriorated is treated with an oxidizing agent, the activity may not be completely recovered even though organic substances on the zeolite are almost completely removed. In this case, probably because the reaction system is in the presence of high-temperature water, if it is used for a long period of time, elimination of aluminum from the zeolite crystal lattice will occur, and the active sites will decrease. And, it is considered that the treatment with the aqueous solution of the inorganic alkali returns aluminum remaining in the zeolite to the crystal lattice.
Further, it is considered that the contact with the inorganic acid ion-exchanges the zeolite which has been made alkaline by the alkali treatment into the acid form.

The type of the oxidizing agent in the present invention is not particularly limited as long as it is generally used for an oxidation reaction of an organic compound. Examples of the oxidizing agent include hydrogen peroxide, ozone, an organic peracid, lead tetraacetate, and iodine. Acids, permanganic acid, nitric acid, nitrous acid, nitrogen oxides and the like. Among them, preferred are hydrogen peroxide and ozone, and particularly preferred is hydrogen peroxide.

The amount of these oxidizing agents is not particularly defined because it varies depending on the level of deterioration of the catalyst, but is usually in the range of 0.05 to 50 kg, preferably 0.1 to 20 kg, more preferably 0.2 to 10 kg per kg of the catalyst. is there.

The temperature at the time of contact with the oxidizing agent in the present invention is not particularly limited as long as the liquid state is maintained, but a relatively high temperature is desirable from the viewpoint of the processing speed, usually 0 to 200 ° C., preferably 20 to 200 ° C. It is in the range of 150 ° C, more preferably 50-100 ° C. The pH of the liquid phase at the time of contact with the oxidizing agent varies depending on the type of the oxidizing agent to be used and is not particularly limited. It is performed in the range.

In the present invention, after being brought into contact with the oxidizing agent in the liquid phase, it may be washed with water or may be brought into direct contact with the next aqueous inorganic alkali solution.

The inorganic alkali aqueous solution used in the present invention is not particularly limited as long as it is an aqueous solution of an alkaline inorganic salt, and examples thereof include an aqueous solution of an alkali metal hydroxide, an alkali metal carbonate, and an alkali metal hydrogencarbonate. . Of these, alkali metal hydroxides are preferred, and sodium hydroxide is particularly preferred.

The amount of the inorganic salt in the aqueous inorganic alkali solution is in the range of 0.1 to 10 equivalents, preferably 0.5 to 5 equivalents per kg of the catalyst,
It is more preferably in the range of 1.0 to 3.0 equivalents. Particularly when an aqueous sodium hydroxide solution is used, the amount of sodium hydroxide is 0.5 to 5 mol, preferably 0.8 to 3 mol per kg of the catalyst.
Mol, more preferably in the range of 1 to 2 mol. If the amount of the inorganic salt is less than 0.1 equivalent, the regenerating effect is low, and if it is more than 10 equivalents, the alkalinity is too strong and crystal breakage due to dissolution of zeolite becomes remarkable.

The amount of the aqueous alkali solution is not particularly limited as long as the amount of the inorganic salt falls within the range described above, but is usually in the range of 1 to 100 kg, preferably 2 to 50 kg, more preferably 3 to 30 kg per kg of the catalyst. It is.

The temperature at the time of contact with the aqueous alkali solution is not particularly limited as long as the liquid phase is maintained, but is usually in the range of 0 to 200 ° C, preferably 10 to 150 ° C, and more preferably 20 to 100 ° C.

In the present invention, after contacting with an alkaline aqueous solution,
Washing with water or contact with an inorganic acid may be directly added.

The inorganic acid in the present invention includes many acids. For example, nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, heteropoly acid and the like can be mentioned. Among them, nitric acid and sulfuric acid are preferable, and nitric acid is particularly preferable.

The amount of the inorganic acid in the present invention is not particularly limited as long as the system becomes acidic, but is usually in the range of 1 to 30 equivalents per kg of the catalyst, preferably 2 to 20 equivalents, more preferably 5 to 20 equivalents.
It is in the range of ~ 15 equivalents.

The temperature at the time of contact with the inorganic acid is usually in the range of 0 to 150 ° C, preferably 10 to 120 ° C, more preferably 20 to 100 ° C.

The embodiment of each treatment of the present invention is not particularly limited, and includes, for example, a fixed bed circulation system, a fixed bed circulation system, a batch system in a slurry state, and the like, and a batch system in a slurry state is preferable. .

The regeneration method of the present invention is effective for a catalyst whose activity has been reduced by an olefin hydration reaction in a liquid phase. The olefin mentioned here includes, for example, chain olefins such as ethylene, propylene, and butene, and cyclic olefins such as cyclopentene, cyclohexene, and cyclooctene.
Among them, the regeneration method of the present invention is particularly effective in the case of cyclohexene.

The zeolite to be regenerated in the present invention is different depending on the type of reaction.
5, ZSM-8, ZSM-11, ZSM-12, ZSM-20, ZSM-35, Z
SM-48 and the like. Among them, ZSM-5 is particularly effective for the regeneration method of the present invention.

(Effect of the Invention) By using the regeneration method of the present invention, it is possible to almost completely regenerate a catalyst whose activity has been reduced by an olefin hydration reaction in a liquid phase. This is very advantageous for industrial implementation.

(Example) Next, the present invention will be described with an example.

Reference Example 1 Water glass (Na ₂ O 8.9% by weight, SiO ₂ 28.9% by weight, H ₂ O 6
(2.2% by weight) 0.39 kg of NaOH and 30 kg of H ₂ O were added to 79.5 kg to obtain a uniform solution. This solution was charged into a 600 autoclave, and while stirring, 225 kg of H ₂ O was added to Al ₂ (SO ₄ ) ₃ · 18H ₂ O
An aqueous solution in which 6 kg and 4.5 kg of concentrated sulfuric acid were dissolved was pumped in at room temperature for 1 hour. Thereafter, the temperature was increased to 170 ° C., and crystallization was performed for 10 hours under stirring conditions of 100 rpm. After that, the synthetic slurry was extracted, and a part thereof was filtered and washed.
X-ray diffraction analysis after drying at 4 ° C for 4 hours, crystallinity
35% ZSM-5.

To 158 kg of the slurry obtained here, 86 kg of water glass, NaO
Add 0.42 kg of H, 33 kg of H ₂ O and add 240 kg of H ₂ O to A
An aqueous solution in which 6.3 kg of l ₂ (SO ₄ ) ₃ · 18H ₂ O and 4.5 kg of concentrated sulfuric acid were dissolved was fed in with a pump for 1 hour while stirring at 100 rpm. Thereafter, the temperature was increased to 150 ° C., and crystallization was performed for 30 hours while stirring at 100 rpm. The resulting slurry 400
Was concentrated to 25% by weight using a rotary filter manufactured by Kotobuki Giken Kogyo Co., Ltd., and then subjected to displacement washing at a constant slurry concentration until the pH of the filtrate reached 10.5.

25 kg of 63% by weight nitric acid and H ₂ O were added to the obtained slurry.
137 kg was added, ion exchange was performed at 50 ° C. for 4 hours, and then concentration was performed with a rotary filter to 30% by weight, and replacement washing was performed at a constant slurry concentration until the pH of the filtrate reached 4.5.

 Thus, an H-type ZSM-5 slurry was obtained.

Reference Example 2 Using the H-type ZSM-5 slurry obtained in Reference Example 1 as a catalyst, a hydration reaction of cyclohexene was performed under the following conditions.

Reaction part oil / slurry volume ratio = 10/90 Slurry concentration: 30% by weight Cyclohexene feed rate: 1.7 [g-cyclohexene / g
−cat · hr] Reaction temperature: 120 ° C. Pressure: 6 kg / cm ² (N ₂ pressurized) Reactor: 4 SUS 304 autoclave (with internal settler at the top of the reaction section) Stirring speed: 200 rpm The slurry was supplied in a pulsed manner so that the slurry concentration was constant.

The concentration of cyclohexanol in the oil at the outlet of the reactor immediately after the start of the reaction was 12.5% by weight, but after continuous operation for 3000 hours, the concentration of cyclohexanol was reduced to 7.0% by weight.

Example 1 The regeneration of the catalyst operated for 3000 hours in Reference Example 2 was performed in the following procedure.

After 300 cc of the slurry was withdrawn from the reactor and the oil and the slurry were separated, the slurry phase was heated in a glass vessel to strip the dissolved oil. By this operation, 250 g of a deteriorated catalyst slurry having a concentration of 35% by weight was obtained.

125 g of 35% by weight hydrogen peroxide solution
Was added dropwise over 2 hours with a pump at 80 ° C. under stirring conditions. After completion of the dropwise addition, stirring was continued at 80 ° C. for another 2 hours, and after confirming that there was no residual hydrogen peroxide, the liquid phase oxidizing agent treatment was terminated. An aqueous solution in which 5.6 g of NaOH was dissolved in 50 g of water was added to this slurry, and an alkaline aqueous solution treatment was performed with stirring at 80 ° C. for 4 hours. At this time, the amount of NaOH per 1 kg of the catalyst was 1.6 mol.

Next, 74.3% by weight of nitric acid 74.3% was added to the obtained slurry.
g was added and the mixture was subjected to an inorganic acid treatment at 90 ° C. for 4 hours with stirring. At this time, the amount of nitric acid (in terms of pure product) per 1 kg of the catalyst was 9 equivalents. The nitric acid slurry was filtered under reduced pressure through a Nutsche filter, and then washed with water until the filtrate pH reached 5.0, to obtain a regenerated catalyst cake having a water content of 38% by weight.

Using this regenerated catalyst, a cyclohexene hydration reaction was carried out in the same SUS 304 autoclave under the same conditions as in Reference Example 2.

As a result, the concentration of cyclohexanol in the oil at the outlet of the reactor immediately after the start of the reaction was 12.6% by weight, and the activity was completely restored.

Comparative Example 1 The slurry after the hydrogen peroxide treatment of Example 1 was filtered under reduced pressure with a Nutsche, and washed with water to obtain a regenerated catalyst cake having a water content of 40% by weight.

Using this regenerated catalyst, a cyclohexene hydration reaction was carried out in the same SUS 304 autoclave under the same conditions as in Reference Example 2.

As a result, the concentration of cyclohexanol in the oil at the outlet of the reactor immediately after the start of the reaction was 11.7% by weight, and had not recovered to the original level.

Example 2 The regeneration of the catalyst operated for 3000 hours in Reference Example 2 was performed in the following procedure.

After extracting 300 cc of the slurry from the reactor and separating the oil and the slurry, the slurry phase was heated in a glass container to perform oil stripping.

Thereafter, using an ozone generator (model 0-3-2) manufactured by Japan Ozone Co., Ltd., an air flow rate of 10 N / hr and an applied voltage of 100 V
The ozone-containing gas generated in
C. for 5 hours.

After the obtained slurry was filtered and washed with water, 140 g of the cake (water content: 40% by weight) was added to an aqueous solution obtained by dissolving 6.7 g of NaOH in 150 g of water, and treated with an aqueous alkaline solution at 90 ° C. for 8 hours under stirring. .

At this time, the amount of NaOH per 1 kg of the catalyst was 1.99 mol. The resulting slurry was filtered, washed with 1 water,
200 g of nitric acid having a concentration of 30% by weight was added, and an inorganic acid treatment was performed under stirring at 90 ° C. for 5 hours.

At this time, the amount of nitric acid (converted to pure product) per 1 kg of catalyst is 12.
Mole.

After the slurry was filtered under reduced pressure with a nutsche, the pH of the filtrate was
Was reduced to 4.8 to obtain a regenerated catalyst cake.

Using this regenerated catalyst, a cyclohexene hydration reaction was carried out in the same SUS 304 autoclave under the same conditions as in Reference Example 2.

As a result, the concentration of cyclohexanol in the oil at the outlet of the reactor immediately after the start of the reaction was 12.5% by weight.

Comparative Example 2 The slurry after the ozone treatment in Example 2 was filtered under reduced pressure with Nutsche, and washed with water to obtain a regenerated catalyst cake having a water content of 38% by weight.

Using this regenerated catalyst, a cyclohexene hydration reaction was carried out in the same SUS 304 autoclave under the same conditions as in Reference Example 2.

As a result, the concentration of cyclohexanol in the oil phase at the outlet of the reactor immediately after the start of the reaction was 11.5% by weight.

Reference Example 3 Using the H-form ZSM-5 slurry obtained in Reference Example 1 as a catalyst, hydration of propylene was carried out under the following conditions.

Dilute the H-ZSM-5 slurry to a concentration of 5% by weight,
The autoclave No. 1 was charged with 420 g, and 95 g of propylene was further charged and reacted with stirring at 250 ° C. for 20 hours. After the reaction, unreacted propylene was removed, and the catalyst was separated by filtration. The concentration of isopropanol in the filtrate was measured, and as a result, it was 9% by weight.

The same experiment was repeated 20 times using the recovered catalyst. As a result, the concentration of isopropanol in the filtrate of the twentieth reaction was 3% by weight.

Example 3 The catalyst after performing the reaction 20 times in Reference Example 3 was regenerated by the following procedure.

A slurry was prepared by adding 100 g of water to 52 g of the deteriorated catalyst cake (water content: 40% by weight).
The mixture was dropped with a dropping funnel over 2 hours under a stirring condition at ° C.
Thereafter, the mixture was filtered and washed with water, added to a solution of 1.2 g of NaOH dissolved in 100 g of water, and treated with an aqueous solution of an inorganic alkali at 70 ° C. for 4 hours under stirring. Thereafter, the mixture was filtered, washed with water, added to 100 cc of 1N sulfuric acid, and subjected to an inorganic acid treatment under stirring at 50 ° C. for 4 hours.

After the obtained slurry was filtered, the filtrate was washed with water until the pH of the filtrate became 5.0 to obtain a regenerated catalyst cake having a water content of 38% by weight.

Using this regenerated catalyst, a hydration reaction of propylene was performed under the same conditions as in Reference Example 3.

As a result, the isopropanol concentration in the filtrate after the reaction was
It was 8.9% by weight.

Comparative Example 3 After the hydrogen peroxide treatment of Example 3, hydration of propylene was carried out under the same conditions as in Reference Example 3, using the cake washed with filtered water.

As a result, the isopropanol concentration in the filtrate after the reaction was
7.7% by weight.

Claims (3)

(57) [Claims] In regenerating a zeolite catalyst subjected to an olefin hydration reaction in a liquid phase, the zeolite is brought into contact with an oxidizing agent in a liquid phase, then with an aqueous inorganic alkali solution, and further with an inorganic acid. A method for regenerating an olefin hydration catalyst. 2. The method according to claim 1, wherein the oxidizing agent is hydrogen peroxide. 3. The method for regenerating an olefin hydration catalyst according to claim 1, wherein the aqueous inorganic alkali solution is an aqueous solution of an alkali metal hydroxide.