JPH03224633A - Method for regenerating catalyst for hydration of olefin - Google Patents

Abstract

PURPOSE:To regenerate a zeolite catalyst at a high rate of regeneration by bringing the catalyst having reduced catalytic activity into successive contact with an oxidizing agent in a liq. phase, an aq. soln. of an inorg. alkali and an inorg. acid. CONSTITUTION:L-zeolite, ZSM-5 or other zeolite catalyst having reduced catalytic activity after use in the hydration reaction of olefin in a liq. phase is brought into successive contact with an oxidizing agent such as hydrogen peroxide or ozone in a liq. phase, an aq. soln. of an alkaline inorg. salt such as the hydroxide or carbonate of an alkali metal and an inorg. acid. By this contact, the zeolite catalyst is regenerated at a high rate of regeneration. The pref. amt. of the oxidizing agent used is about 0.1-20kg per 1kg of the catalyst and the pref. amt. of the inorg. salt in the aq. alkali soln. is about 0.5-5equiv. per 1kg of the catalyst. The inorg. acid is preferably nitric acid, sulfuric acid, hydrochloric acid or phosphoric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for regenerating a catalyst when producing alcohol, which is important as a raw material for various chemicals, by hydration of an olefin.

(Prior Art) When a hydration reaction of olefin is carried out in a liquid phase using zeolite as a catalyst, the activity of the catalyst gradually decreases as the reaction progresses. A method for regenerating a catalyst whose activity has decreased is a method of regenerating it in a liquid phase using an oxidizing agent such as hydrogen peroxide, ozone, organic peracid, or nitric acid (Japanese Patent Laid-Open No. 61-234945
zeolite is exchanged with alkali metal ions in advance and then exchanged with a gas containing molecular oxygen for 200~
A method has been proposed in which the alkali metal ions are removed by re-exchange after contact at 600°C (see Japanese Patent Laid-Open No. 61-234946).

(Problems to be Solved by the Invention) Among the conventional techniques, the regeneration method using hydrogen peroxide, ozone, etc., which is a method using an oxidizing agent in the liquid phase, is true if the reduction in catalyst activity is small. Although this method has a high rate and is effective, it has been difficult to completely restore the activity when the activity has significantly decreased.

These drawbacks arise when the catalyst is used in a completely mixed slurry system and is periodically withdrawn and regenerated at a certain rate.
This is particularly problematic because there is always a certain proportion of catalyst that remains unregenerated for a long period of time.

In addition, the method of exchanging with alkali metal ions in advance and then contacting with molecular oxygen requires a long regeneration process;
Since it involves liquid-phase treatment and gas-phase treatment, it involves operations such as drying and baking, which poses the problem of extremely complicated operations.

(Means for Solving the Problems) The present inventors have conducted intensive studies on a method that can achieve a high regeneration rate even in the regeneration of catalysts whose activity has significantly decreased. After regeneration, the inventors have discovered that the activity can be almost completely restored by contacting with an aqueous inorganic alkaline solution and then with an inorganic acid, and have completed the present invention.

That is, in regenerating a zeolite catalyst that has been subjected to an olefin hydration reaction in a liquid phase, the present invention involves contacting the zeolite with an oxidizing agent in the liquid phase, then contacting it with an aqueous inorganic alkali solution, and then contacting the zeolite with an inorganic acid. This is a method for regenerating an olefin hydration catalyst, which is characterized by contacting the catalyst.

The cause of the decrease in zeolite activity in this reaction system is not clearly understood, so it is not clear why alkaline aqueous solution treatment is effective, but the following may be considered.

In the hydration reaction of olefins in the liquid phase, usually
An acid type zeolite is used, but on an acid catalyst, the polymerization reaction of olefins and the side reactions that produce ether, etc., which are subsequent products of the produced alcohol, occur simultaneously. These high boiling products clog the pores of the zeolite and cause a decrease in activity. It is thought that regeneration using an oxidizing agent in the liquid phase removes these high-boiling substances by oxidation.

On the other hand, when a catalyst that has been used for a long time and has significantly deteriorated is treated with an oxidizing agent, the activity may not be completely recovered even though most of the organic matter on the zeolite has been removed. In this case, it is probably because the reaction system is in the presence of high-temperature water, and when used for a long period of time, aluminum is desorbed from the crystal lattice of the zeolite, resulting in a decrease in the number of active sites. The inorganic alkaline aqueous solution treatment is thought to function to return the aluminum remaining in the zeolite to the crystal lattice.

Further, contact with an inorganic acid is thought to cause ion exchange of the zeolite, which has become alkaline through alkali treatment, into an acid form.

The type of oxidizing agent used in the present invention is not particularly limited as long as it is commonly used in the oxidation reaction of organic compounds, but examples include hydrogen peroxide, ozone, organic peracid, lead tetraacetate, and periodic acid. Examples include acids, permanganic acid, nitric acid, nitrous acid, nitrogen oxides, and the like.

Preferred among these are hydrogen peroxide and ozone;
Particularly preferred is hydrogen peroxide.

The amount of these oxidizing agents varies depending on the level of deterioration of the catalyst and is not particularly specified, but is usually 0.05 to 50 kg per 1 kg of catalyst, preferably 0.05 to 50 kg per 1 kg of catalyst.
It is in the range of 1 to 20 kg, more preferably 0.2 to 10 kg.

The temperature during contact with the oxidizing agent in the present invention is not particularly limited as long as the liquid state is maintained, but from the viewpoint of processing speed, a relatively high temperature is desirable, usually 0 to 200°C, preferably 20°C. 150°C1, more preferably 50-10
It is in the range of 0°C. In addition, the pH of the liquid phase when brought into contact with an oxidizing agent varies depending on the type of oxidizing agent used and is not particularly stipulated, but since the decomposition of the oxidizing agent is significant on the alkaline side, it is usually pH 3 to 7. It is carried out within the range of

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

The inorganic alkaline 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 include aqueous solutions of alkali metal hydroxides, alkali metal carbonates, alkali metal hydrogen carbonates, etc. . Among them, preferred are alkali metal hydroxides, and particularly preferred is sodium hydroxide.

The amount of inorganic salt in the inorganic alkaline aqueous solution is in the range of 11 to 10 equivalents of O per 1 - of catalyst, preferably 0.5 to 5
equivalent, more preferably in the range of 1.0 to 3.0 equivalent. In particular, when using an aqueous sodium hydroxide solution, the amount of sodium hydroxide is 0.5 to 5 mol per kg of catalyst,
The amount is preferably 0.8 to 3 mol, more preferably 1 to 2 mol. If the amount of this inorganic salt is less than 0.1 equivalent, the regeneration effect will be low, and if it is more than 10 equivalents, the alkalinity will be too strong and crystal destruction due to zeolite dissolution will be significant.

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

There is no particular restriction on the temperature when contacting with the alkaline aqueous solution as long as the liquid state is maintained, but it is usually 0 to 200°C.
Preferably 10-150°C1, more preferably 20-150°C
The range is 100°C.

In the present invention, after contacting with an aqueous alkaline solution, washing with water may be performed, or an inorganic acid may be directly added and brought into contact.

The inorganic acid in the present invention includes many acids.

Examples include nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, heteropolyacid, etc. Among them, nitric acid and sulfuric acid are preferred,
Particularly preferred is nitric acid.

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

The temperature during contact with the inorganic acid is usually 0" to 150°C, preferably 10 to 120°C, more preferably 20 to 1
It is in the range of 00°C.

The embodiment of each treatment of the present invention is not particularly limited, and examples thereof include a fixed bed distribution method, a fixed bed circulation method, a batch method in a slurry state, etc., but a batch method in a slurry state is preferable. .

The regeneration method of the present invention is effective for catalysts whose activity has decreased due to the olefin hydration reaction in the liquid phase. The olefins mentioned here include, for example, chain olefins such as ethylene, propylene, butene, cyclopentene, cyclohexene,
Examples include cyclic olefins such as cyclooctene. Among these, the regeneration method of the present invention is particularly effective in the case of cyclohexene.

The zeolite regenerated in the present invention varies depending on the type of reaction, but for example, faujasite, L-type zeolite, ferrierite, offretite, erionite, zeolite beta, mordenite, ZSM-4, ZS
M-5, ZSM-8, ZSM-11, ZSM-12, Z
Examples include SM-20, ZSM-35, and ZSM-48. Among them, the regeneration method of the present invention is particularly effective for ZSM-
It is 5.

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

(Example) Next, the present invention will be explained with examples.

Reference Example 1 Water glass (Nazo 8.9% by weight, 5iOz28.
9% by weight, tho62.2% by weight) 79.5kg of N
39 kg of a0HO and 30 kg of H, o were added to obtain a homogeneous solution. 600 yen of this solution! Pour into the autoclave, stir, and heat! 0225kg and 80z (SO
4) An aqueous solution containing 188.06 kg of s and 4.5 kg of concentrated sulfuric acid was pumped in at room temperature for 1 hour. Then increase the temperature to 170″C and run at 1100rpm.
Crystallization was carried out for 10 hours under stirring conditions. After that, the synthetic slurry was taken out, a part was filtered and washed, and heated at 120°C for 4 hours.
As a result of X-ray diffraction analysis after drying for a period of time, the crystallinity is 35%.
It was ZSM-5.

To 158 kg of the slurry obtained here, 86 kg of water glass was added.
g, NaOH0.42kg, and more II! 033
kg, and then convert it to Hz0240kg and 80z (S
Oa) s ・188206.3 kg and concentrated sulfuric acid 4.5
An aqueous solution in which 1.0 kg was dissolved was pumped in for 1 hour while stirring at 1100 rpm. Then increase the temperature to 150°
C., and crystallization was carried out for 30 hours while stirring at 1100 rpm. The resulting slurry was 400! ! , was concentrated to 25% by weight using a rotary filter manufactured by Kotobuki Giken Kogyo Co., Ltd., and then displacement washing was performed at a constant slurry concentration until the pH of the filtrate reached 10.5.

25 kg of nitric acid with a concentration of 63% was added to the resulting slurry.
and 820,137 kg were added, ion exchanged at 50°C for 4 hours, and then filtered to 30% by weight using a rotary filter.
The pH of the filtrate is 4.5 at a constant slurry concentration.
Displacement cleaning was performed until the

In this way, 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 carried out 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 crab 6 kg/cffl (Nz Pressure) Reactor: 4 l2StlS 304 autoclave (with internal settler at the top of the reaction part) Stirring rotation speed: 20Or
pm Water was supplied in pulses so that the slurry concentration remained constant.

Immediately after the start of the reaction, the cyclohexanol concentration in the reactor outlet oil was 1265% by weight, but after that, it was 3000% by weight.
After continuous operation for hours, the cyclohexanol concentration was 7.
．． It decreased to 0% by weight.

Example 1 The catalyst that had been operated for 3000 hours in Reference Example 2 was regenerated according to the following procedure.

After withdrawing 300 cc of slurry from the reactor and separating the oil and slurry, the slurry phase was heated in a glass vessel to strip off the dissolved oil. Through this operation, 250 g of degraded catalyst slurry having a concentration of 35% by weight was obtained.

To this slurry, add 125% hydrogen peroxide solution with a concentration of 35% by weight.
g was added dropwise using a pump over 2 hours under stirring conditions at 80°C. After the dropwise addition was completed, 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 completed. Add Na01l to this slurry5. 6
Add an aqueous solution of g dissolved in 50 g of water, and heat at 80°C for 4 hours.
Alkaline aqueous solution treatment was performed while stirring for hours. At this time, the amount of Naotl per 1 kg of catalyst was 1.6 mol.

Next, the obtained slurry was added with nitrate M74 at a concentration of 61% by weight.
．． 3 g was added thereto and treated with an inorganic acid while stirring at 90° C. for 4 hours. The amount of nitric acid (purity equivalent) per 1 kg of catalyst at this time is g equivalent.

This nitric acid slurry was filtered under reduced pressure using a Nutsche filter, and then washed with water until the pH of the filtrate reached 5.0 to obtain a cake of regenerated catalyst with a water content of 38% by weight.

A hydration reaction of cyclohexene was carried out under the same conditions as in Reference Example 2 in 11 SUS 304 autoclaves using the regenerated catalyst of No. 2.

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

Comparative Example 1 The slurry treated with hydrogen peroxide in Example 1 was filtered under reduced pressure using a Nutsche filter, and washed with water No. 21 to obtain a cake of regenerated catalyst having a water content of 40% by weight.

Using this regenerated catalyst, hydration reaction of cyclohexene was carried out under the same conditions as in Reference Example 2 in 11 SOS 304 autoclaves.

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

Example 2 The catalyst that had been operated for 3000 hours in Reference Example 2 was regenerated using the following procedure.

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

Then, using an ozone generator (model 0-3-2) manufactured by Nippon Ozone Co., Ltd., ozone-containing gas was generated at an air flow rate of 10 Nff/hr and an applied voltage of 100 cm, and was poured into the slurry at 80°C for 15 hours. supplied.

After filtering and washing the obtained slurry with water, 140 g of cake (
water content: 40% by weight), 6.7g of NaOH, and 150g of water.
In addition to the aqueous solution dissolved in , an alkaline aqueous solution treatment was performed under stirring conditions at 90° C. for 18 hours.

At this time, the amount of Na0HO per 1 kg of catalyst was 1. 9
It was 9 moles. The resulting slurry was filtered and washed with water from Step 12, and then 200 g of nitric acid with a concentration of 30% by weight was added.
Inorganic acid treatment was performed under stirring conditions at 0°C for 5 hours.

At this time, the amount of nitric acid (purity equivalent) per 1 kg of catalyst was 121 mol.

After filtering this slurry under reduced pressure using Nutsche, the pH of the filtrate was
A cake of regenerated catalyst was obtained by washing with water until the pH value reached 4.8.

Using this regenerated catalyst, hydration reaction of cyclohexene was carried out under the same conditions as in Reference Example 2 in 11 SO5304 autoclaves.

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

Comparative Example 2 The slurry after the ozone treatment of Example 2 was filtered under reduced pressure using a Nutsche filter, and washed with water of No. 21 to obtain a regenerated catalyst cake with a water content of 38% by weight.

Using this regenerated catalyst, hydration reaction of cyclohexene was carried out under the same conditions as in Reference Example 2 in a 1ffi SO5304 autoclave.

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-type ZSM-5 slurry obtained in Reference Example 1 as a catalyst, a propylene hydration reaction was carried out under the following conditions.

H-ZSM-5 slurry was diluted to a concentration of 5% by weight,
17! Add 420g to an autoclave, add 95g of propylene, and heat at 250°C for 2 hours without stirring.
The reaction was allowed to proceed for 0 hours. After the reaction, unreacted propylene was removed, the catalyst was filtered off, and the concentration of isopropanol in the filtrate was measured and found to be 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 20th reaction was 3% by weight.

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

100 g of water to 52 g of degraded catalyst cake (water content 40% by weight)
After adding g to slurry, 35% hydrogen peroxide solution 6
0 g was added dropwise using a dropping funnel over 2 hours under stirring conditions at 80°C. After that, it was filtered, washed with water, and 1.2 g of N
Add aOH to a solution of 100 g of water and heat to 70°C.
An inorganic alkali aqueous solution treatment was carried out under stirring conditions for 4 hours. Thereafter, it was filtered, washed with water, and treated with an inorganic acid in addition to 100 cc of IN sulfuric acid at 50° C. for 4 hours under stirring conditions.

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

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

As a result, the concentration of isopropanol in the filtrate after the reaction was 8
．． It was 9% by weight.

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

As a result, the concentration of isopropanol in the filtrate after the reaction was 7.
．． It was 7% by weight.

(1 other person)

Claims (3)

[Claims] (1) In regenerating the zeolite catalyst subjected to the olefin hydration reaction in the liquid phase, the zeolite is brought into contact with an oxidizing agent in the liquid phase, then brought into contact with an aqueous inorganic alkali solution, and then brought into contact with an inorganic acid. A method for regenerating an olefin hydration catalyst, characterized by: (2) The method for regenerating an olefin hydration catalyst 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.