JPH03114536A - Regeneration of titanosilicate catalyst - Google Patents

Abstract

PURPOSE:To regenerate a catalyst extremely effectively by a method wherein a deteriorated catalyst is baked at a predetermined temp. in the presence of an oxygen-containing gas or washed with a solvent at a temp. higher than that at the time of epoxidation. CONSTITUTION:An epoxide is produced from olefin and hydrogen peroxide using a crystalline titanosilicate catalyst. The catalyst which has been deteriorated during this time is baked at a temp. of 400-500 deg.C in the presence of a gas contg. 5-99vol.% of oxygen and an inert gas for the balance. It may alternatively be regenerated at a temp. higher by 5-150 deg.C than at the time of epoxidation by washing with a solvent such as water, ketone and alcohol. The catalyst is thus regenerated efficiently and economically and made usable for an extended period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for industrially producing epoxides from olefins, hydrogen peroxide, and crystalline titanosilicate catalysts. More specifically, the present invention relates to a method for efficiently regenerating a catalyst so that it can be used for an epoxidation reaction over a long period of time.

[Conventional technology]

Various methods are known for producing epoxides from olefins and hydrogen peroxide in the presence of catalysts. Among them, the method using a type of crystalline titanosilicate called TS-1 as a catalyst described in JP-A No. 59-51273 uses a heterogeneous reaction system, so it is easy to separate the catalyst and the product epoxide. This is an industrially excellent method.

However, when the above method was tested by the present inventors, it was found that it could not be operated for a long period of time due to severe deterioration of catalyst activity, and therefore could not be an economical process. In order to make the process economically viable, it is considered essential to regenerate the titanosilicate catalyst whose activity has deteriorated and use it in the epoxidation reaction many times to increase the epoxide production per unit catalyst. .

As a method for regenerating the titanosilicate catalyst whose activity has deteriorated, it is calcined in air at 550°C (G, Perego
, et al, + Proc, 7th Inter
n, ZeoliteConfer, +1986.
Tokyo, p. 827) is known.

On the other hand, when titanosilicate is exposed to temperatures higher than 500°C, titanium in crystal lattice positions is removed (B,
Kraushaar-Czarnetki, et a.
l,, Catal.

Lett, 2, 43 (19B9)).

Therefore, implementation of the above-described method is not preferred as it results in destruction of the titanosilicate.

[Problem to be solved by the invention]

The object of the present invention is to combine an olefin, hydrogen peroxide, and
An object of the present invention is to provide a method for regenerating a catalyst that has deteriorated during use in a reaction for producing an epoxide from a crystalline titanosilicate catalyst.

[Means to solve the problem]

The inventors of the present invention have intensively studied methods for regenerating titanosilicate catalysts, and as a result, have found two extremely effective methods and have completed the present invention.

The first method is to sinter the catalyst in an atmosphere of oxygen-containing gas. The firing temperature is 400-500°C. The oxygen-containing gas contains 5 to 99 vol% oxygen and the remainder is an inert gas, preferably air. If the calcination temperature exceeds 500°C, the titanosilicate catalyst will be destroyed, and if the calcination temperature is lower than 400°C, the catalyst will not be regenerated sufficiently.

The second method is to wash the catalyst with an appropriate solvent. In this case, the treatment temperature in particular has an important influence on the regeneration effect. To the extent that the solvent used does not decompose, the temperature should be slightly lower than that during the epoxidation reaction (5 to 150℃, preferably 5 to 120℃).
℃) It is particularly effective to carry out at high temperature, usually 0 to 2
It is carried out at 00°C, preferably 40 to 180°C, and a pressure of 1 to 100 atm.

The cleaning solvent used in the present invention dissolves ordinary organic substances and has a carbon number not very large (preferably 9 or less).
selected from the group consisting of water, alcohols, ketones, hydrocarbons, halogenated hydrocarbons, esters, nitriles, and acids.

Suitable alcohols include methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1-butanol, 2-butanonyl, allyl alcohol, and ethylene glycol.

Suitable ketones include acetone, 2-butanone, 2-methylbutanone, 2-pentanone, 3-pentanone, 2-methyl-4-pentanone, and cyclohexanone.

Suitable hydrocarbons include propane, 1-butene, 2-butene, isoprene, benzene, toluene, xylene, and trimethylbenzene.

Examples of halogenated hydrocarbons include dichloromethane chloroform, carbon tetrachloride, 1.1-dichloroethane, 1.2-
dichloroethane, 1,1.1-) dichloroethane, 1
, 1.2-) dichloroethane, 1.1.1.2-tetrachloroethane, Ll, 2.2-tetrachloroethane,
Allyl chloride, dibromomethane and chlorobenzene are preferred.

As the ester, methyl formate, methyl acetate, ethyl acetate, butyl acetate, and ethyl propionate are preferred, and as the nitrile, acetonitrile is preferred.

As the acid, formic acid, acetic acid, and propionic acid are suitable.

When the epoxidation reaction is carried out in a fixed bed or continuous stirred tank,
The catalyst is washed with a solvent by supplying a washing solvent to the reactor instead of the epoxidation reaction raw material.

When the epoxidation reaction is carried out batchwise, the catalyst is washed with a solvent after the reaction, after the solution is extracted as a supernatant.
This is carried out by adding a washing solvent to the reactor, stirring it, and drawing out the supernatant liquid again.

Whether to employ calcination or solvent washing is determined by the type of reactor after considering economic efficiency. It is also possible to use both together.

The present invention is applied when the compositional formula is xTioz (1-
x) An olefin epoxidation catalyst containing a crystalline titanosilicate represented by SiO (0.0001<x<0.5, preferably 0.001<x<0.05) as an active ingredient.

In synthesizing titanosilicate, first, a reaction mixture consisting of a silica source, a titanium source, a nitrogen-containing compound, and water is prepared. The silica source is tetraalkoxy silicon or colloidal silica. The titanium source is tetraalkoxytitanium or titanium tetrachloride. The nitrogen-containing compound is a tetraalkylammonium ion, preferably tetrapropylammonium hydroxide or tetrabutylammonium hydroxide. Further, as the nitrogen-containing compound, triethanolamine, jetanolamine, piperidine, or NH2(CHz)-NHK (where n is 1 to 9) is used.

The molar ratio of the reactants is S i Ox/T i Oz = 10-50H, O/S
tO, -10 to 100 nitrogen-containing compound/S i Oz-0, 05 to 1.

The above reaction mixture was heated in an autoclave for 100 to 22 hours.
Hold at 0°C for 2-1000 hours. Next, take out the solid matter, dry it, and then store it in the air at 400-500°C for 1 to 30 minutes.
Bake for 100 hours.

By the method described above, titanosilicate having various crystal forms can be synthesized. Tables 1.3 and 2.4 respectively show the X-ray diffraction spectra (C
u- and α) show the main patterns of the infrared absorption spectrum.

01±0゜ 2 440～ 460 In Tables 1 to 4, vs = very strong S two strong m = medium W-weak represents.

The epoxidation reaction of the present invention is carried out using an olefin, hydrogen peroxide, and a titanosilicate catalyst in the presence or absence of a solvent at 0 to 150°C and 1 to 100 atmospheres.

As the olefin, ethylene, propylene, 1-butene, 2-butene, 1-hexene, 1-octene, isobutyne, 1,3-butadiene, isoprene, cyclohexene, allyl chloride or allyl alcohol are used.

Hydrogen peroxide is 1 to 95 wt%, preferably 5 to 60 wt%
% aqueous solution. As a solvent, water, methanol, 2-
Propanol, 2-methyl-2-propanol, acetone, acetonitrile, acetic acid, propionic acid or mixtures of some of these are used.

〔Example〕

Preparation of titanosilicate catalyst 34.2 g of tetraethoxy silicon (164 mmol) and 1.9 tetraisopropoxy titanium (6.4 mmol) were added to a 200 ml flask under a nitrogen atmosphere. While stirring, 38.9 g of 20-25% aqueous tetrapropylammonium hydroxide solution was gradually added dropwise.

By stirring at 90°C for 3 hours, ethanol
0rnfl was distilled off. The contents were transferred to a titanium autoclave, and 81% water was added. Under self-generated pressure, 17
Heated at 5°C for 7 hours. After cooling, remove the contents and
The supernatant liquid was removed by centrifugation, water was added, and after stirring, centrifugation was performed again, and the precipitate was taken out, dried at 110°C for 4 hours, and then calcined at 500°C for 5 hours. The X-ray diffraction spectrum of the product was as shown in Table 1, and was consistent with the titanosilicate described in JP-A-56-96720. Scanning electron micrograph shows that the average particle size is 0.
．． It was 3 μm.

Ta.

Examples and comparative examples of the present invention are shown below, but these do not necessarily indicate the optimum conditions for catalyst regeneration, and the present invention is not limited thereto. In addition, Comparative Example 1 and Example 1.2 were carried out using the same catalyst,
Comparative Example 3 and Examples 4-7 were conducted continuously without taking out the catalyst from the reaction tube.

Comparative Example 1 A 30 rnl flask equipped with a condenser tube was charged with powdered 0.0 rnl.
4g titanosilicate, 12g methanol, 4g
of allyl chloride (52.3 mmol, 3.2 g of 30wt
% aqueous hydrogen peroxide solution (28.2 mmol) was added in this order. This suspension was stirred at 40°C for 3 hours. After cooling,
The flask was centrifuged and the supernatant liquid was collected.

Add the same amount of methanol, allyl chloride, and
Hydrogen peroxide was added and the same operation as above was repeated. The product was analyzed by gas chromatography. Table 5 shows the results.

Example 1 The epoxidation reaction was repeated several times as in Comparative Example 1, and when the shrimp chlorohydrin yield reached 40.5%,
Add 12g of methanol to the flask containing the deteriorated catalyst.
was added and stirred at 75°C for 1 hour to perform washing. After cooling, the flask was centrifuged and the supernatant liquid was removed. After repeated washing, the epoxidation reaction was performed again in the same manner. As shown in Table 5, it can be seen that the catalyst activity was slightly recovered.

Example 2 The catalyst used in Example 1 was taken out of the flask and calcined in air at 480°C for 3 hours. The catalyst was taken out and the epoxidation reaction was performed again in the same manner.

As shown in Table 5, it can be seen that the catalyst activity has been recovered.

Comparative Example 2 In this comparative example, when the treatment temperature during catalyst regeneration is low,
This is an example of a case where it may have the opposite effect. Comparative example 1
Repeat the same operation until the epichlorohydrin yield is 5.
When the concentration reached 3.9%, the same treatment as in Example 1 was carried out at 40° C. using acetone as a cleaning solvent instead of methanol. Epichlorohydrin yield is 46.0%
Met.

Example 3 The same operation as in Comparative Example 1 was performed except that 1-hexene was used instead of allyl chloride and the reaction temperature was changed to 63°C. The yield of 1,2-epoxyhexene was 30.2%. This operation was repeated several times, and when the yield of 1,2-epoxyhexene reached 19.1%, the catalyst was taken out from the flask and calcined in air at 500°C for 3 hours.

When the epoxidation reaction was carried out again in the same manner, 1.2
-The yield of epoxyhexene was 30.4%.

Comparative Example 3 2.1 g of colloidal silica (Snowtex UP manufactured by Nissan Chemical, containing 20 to 21 wt% of 5iOz) and 2.
．． 27g of titanosilicate was mixed, dried, and
After firing at 00°C, the mixture was pulverized to obtain a fine powder of 120 mesh or more. Take 0.78 g of this and add diluent Celite (1
, 4 g) and packed into a glass reaction tube with an inner diameter of 8 mm. Note that the internal volume of the catalyst layer was 3.8 ml.

A mixture of allyl chloride, hydrogen peroxide (30 wt% aqueous solution), methanol, and ammonia (0.5 wt% aqueous solution) (
Weight ratio = 40:32: 120: 1: Molar ratio = 5
2.3:28.2:374.5:0.1) to 0.29mA! /n+in was continuously supplied to the reaction tube. The reaction tube was immersed in a water bath at 55°C, and a resistance was attached so that the pressure at the outlet of the reaction tube was 4 to 14 kg/cfflG. The product was cooled with ice water and analyzed by gas chromatography. The epichlorohydrin yield when steady state was reached was 82.8%, as shown in Table 6.

Example 4 While continuing Comparative Example 3, when the epichlorohydrin yield decreased to 58.0%, methanol was supplied to the reaction tube instead of the raw material liquid at the same flow rate.

The reaction tube was immersed in a 70°C water bath for 3 hours. After cooling, an epoxidation reaction was carried out in the same manner as in Comparative Example 3, and the epichlorohydrin yield was 73.0%, indicating that the catalytic activity had been slightly recovered.

Example 5 This example shows that higher treatment temperatures in solvent cleaning of degraded catalysts are more effective.

While continuing Example 4, the epichlorohydrin yield was 6.
When the temperature decreased by 6.7%, the reaction tube, in which methanol was supplied at the same flow rate instead of the raw material solution, was immersed in a water bath at 85°C for 3 hours. After cooling, an epoxidation reaction was carried out in the same manner as in Comparative Example 3, and the epichlorohydrin yield was 83.1%.

Example 6 While continuing Example 5, the epichlorohydrin yield was 6.
When the concentration decreased to 4.3%, a 1:1 (weight ratio) solution of acetone and 2-methyl-4-pentanone was supplied to the reaction tube at the same flow rate instead of the raw material liquid.

The reaction tube was immersed in an 85°C water bath for 3 hours. After cooling, an epoxidation reaction was carried out in the same manner as in Comparative Example 3, and the epichlorohydrin yield was 81.6%.

Example 7 While continuing Example 6, the epichlorohydrin yield was 5.
When the concentration decreased to 8.4%, benzene was flowed into the reaction tube at the same flow rate instead of the raw material liquid. The reaction tube was immersed in an 85°C water bath for 3 hours. After cooling, an epoxidation reaction was carried out in the same manner as in Comparative Example 3, and the epichlorohydrin yield was 85.8%.

Table 5 Epichlorohydrin Yield (%) Table Epichlorohydrin Yield (%) [Effects of the Invention] As shown in the Examples, if the titanosilicate catalyst is regenerated many times by the method of the present invention, it will be Can be used for a long time.

Claims (9)

[Claims] (1) In a reaction for producing an epoxide from an olefin, hydrogen peroxide, and a crystalline titanosilicate catalyst, the degraded catalyst is heated for 40 minutes in the presence of an oxygen-containing gas.
A method for regenerating a titanosilicate catalyst, characterized in that the titanosilicate catalyst is regenerated by firing at 0 to 500°C or by washing with a solvent at a temperature 5 to 150°C higher than that during the epoxidation reaction. 2. The method of claim 1, wherein the solvent is selected from the group consisting of water, alcohols, ketones, hydrocarbons, halogenated hydrocarbons, esters, nitriles, and acids. (3) The alcohol is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol, 1-butanol, 2-butanol, allyl alcohol, and ethylene glycol. The method according to claim 2. (4) The ketone is selected from the group consisting of acetone, 2-butanone, 2-methylbutanone, 2-pentanone, 3-pentanone, 2-methyl-4-pentanone, and cyclohexanone. the method of. 5. The method of claim 2, wherein the hydrocarbon is selected from the group consisting of propane, 1-butene, 2-butene, isoprene, benzene, toluene, xylene, and trimethylbenzene. (6) The halogenated hydrocarbon is dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2
-dichloroethane, 1,1,1-trichloroethane, 1
, 1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane,
3. The method of claim 2, wherein the compound is selected from the group consisting of dibromomethane, allyl chloride, and chlorobenzene. 7. The method of claim 2, wherein the ester is selected from the group consisting of methyl formate, methyl acetate, ethyl acetate, butyl acetate, and ethyl propionate. (8) The method according to claim 2, wherein the nitrile is acetonitrile. 9. The method of claim 2, wherein the acid is selected from the group consisting of formic acid, acetic acid, and propionic acid.