KR900004926B1 - Method for preparing epichlorohydrins - Google Patents

Abstract

A epichlorohydrin prepn. comprises reacting 2-alkyl allyl chloride contg. C1-3 alkyl, with an alkyl hydroperoxide in the presence of a catalyst having Ti atoms bound to a SiO2 carrier via O atoms and having 3-6 silanol gps per 2nm2 of the carrier. The catalyst is heat teated at 100-250 deg.C. The alkyl hydroperoxide is pref. e.g. cumene hydroperoxide. The 2-alkylallyl chloride is (meth) allyl chloride. The heat treatment is effected in a non reducing gas atmos. The epichlorohydrin is prepd at low temp. in high yield and selectively.

Description

Process for producing epichlorohydrin

1 is an infrared absorption spectral analysis chart showing a state in which a silanol group on a catalyst carrier in the present invention adsorbs aryl chloride as a reaction material.

In the figure, CAT indicates the absorbance of the catalyst before adsorbing the aryl chloride, 5 Torr indicates the absorbance of the catalyst which adsorbed the aryl chloride under the condition of 5 Torr, and 260 Torr of the catalyst adsorbed the aryl chloride under the condition of 260 Torr. Display absorbance.

The present invention relates to a method for producing epichlorohydrin from arylchlorides and alkylhydro peroxides.

The chlorohydrin method, the chlorination method of aryl alcohol, and the peroxide method are known as a manufacturing technique of epichlorohydrin.

The chlorohydrin method has a high chlorine source unit by using aryl chloride as a raw material and chlorohydrin as an oxidant, and the raw material of the aryl alcohol method is expensive. As the peroxide method, a method using tert-butyl hydroperoxide, ethylbenzene hydroperoxide, cumene hydroperoxydi, hydrogen peroxide, peracid and the like is known. In addition, as a method of using a homogeneous catalyst, Japanese special public service 48-19609, Japanese special service 45-17649, Tr.Mo sk, khim.Tekhno.Inst., 74-19-20 (1973), are known. In this method, the catalyst is dissolved in the reaction product and the recovery is complicated. In addition, West German Patent No. 2,334,315, US Patent No. 4,021,454, Journal Oak Catalesis, and the like are described for the synthesis of epichlorohydrin by epoxidation of propylene or aryl chloride with an alkyl hydride with peroxide in the presence of a solid catalyst. J. Catalysis) 31 438 (1973).

In these documents, the silica gel is impregnated with titanium tetrachloride, and the reaction is carried out using a catalyst calcined at 500 ° C or higher, preferably 800 ° C.

In these documents, tertbutyl hydroperoxide which is stable to hydroperoxide is used, and 2,6-di-tert-butyl-4-methylphenol is added and reacted as a stabilizer, and the epichlorohydrin selectivity is 73% (hydr Peroxide, but the selectivity is 55% when ethylbenzene hydroperoxide is used and the selectivity is only 8% when cumene hydroperoxide is used. Therefore, it is difficult to industrially produce epichlorohydrin by these methods.

In the presence of a heterogeneous solid catalyst, without adding an antioxidant using tertbutylhydroperoxide, ethylbenzenehydroperoxide, cumenehydroperoxide or cyclohexylhydroperoxide which is economically advantageous as alkylhydroperoxide, It is not known to epoxidize arylchlorides to obtain epichlorohydrin at high selectivity.

In the aryl chlorides, it is described in the above document that the reactivity of the double competition is remarkably low due to the electron narrowing of the chlorine atom, the epoxidation reaction becomes difficult, and ends with the unnecessary decomposition of the hydroperoxide.

MEANS TO SOLVE THE PROBLEM In order to solve the said problem, the present inventors earnestly examined and discovered that the objective of this invention is achieved by using the catalyst which has a titanium atom and a silanol group on a silicon dioxide carrier, and completed this invention.

That is, the present invention relates to a titanium atom bonded to a silicon dioxide carrier via an oxygen atom, and in the presence of a catalyst having at least one square nanometer silanol group on the same carrier, arylchlorides and alkylhydroperoxides; It is a method for producing epichlorohydrin by the reaction of.

In the present invention, aryl chlorides mean aryl chloride or 2-alkylaryl chloride in which hydrogen at the second position of aryl chloride is substituted with an alkyl group.

In the present invention, alkylhydroperoxide means cumenehydroperoxide, ethylbenzenehydroperoxide, tert-butylhydroperoxide or cyclohexylhydroperoxide.

Therefore, in the present invention, epichlorohydrin means epichlorohydrin or 2-alkyl epichlorohydrin, and the aryl chlorides described above become corresponding epichlorohydrins, respectively.

The catalyst in the present invention is one having a titanium atom bonded through an oxygen atom on a silicon dioxide carrier and a silanol group on the same carrier. Generally, a titanium halide, an alkoxy titanium, a carbonyl compound of titanium, or the like is used. It is obtained by contacting a surface silanol group with a branched silica hydrogel and then heating at a low temperature necessary for remaining the silanol group in an atmosphere of a non-reducing gas or an oxidizing gas. Alternatively, the surface of the carrier silanol may be partially etherified with alcohols or esterified with acids, and after supporting the titanium compound, the silanol group may be regenerated on the surface by removing the ether group or ester group, As another method, the titanium compound is supported after carbohydrate from a silica carrier in advance and the surface is changed to a siloxane bond, and then hydrated by steam treatment or the like, and the required number of silanol groups may be provided.

Here, silica hydrogel can be used in various processes such as precipitation from sodium silicate, decomposition of silicate, combustion of ethyl silicate, etc., but has silanol groups on the surface and a specific surface area of 1 m ² / g or more, preferably 100 m ² / g or more, pore diameter is 50 kPa or more, preferably 100 kPa or more, pore volume is 0.01 ml / g or more, preferably 0.1 ml / g or more, and the number of silanol groups on the surface is 1 mm ² (1 square nanometer) = 10 ^-18 m ² ) per one, preferably at least three.

As a titanium compound, a liquid thing is easy to use, titanium tetrachloride, alkoxy titanium, etc. are used, It can be made to impregnate these directly, or can dilute and impregnate in solvents, such as hydrocarbons and alcohols.

When supporting, the titanium compound is contacted with silica gel in an inert gas atmosphere, and then the solvent is heated and removed under normal or reduced pressure, followed by non-reducing gas such as nitrogen, alcon, carbon dioxide, or oxygen-containing gas, For example, the catalyst may be prepared by heating at a temperature of 100 ° C. or more and 500 ° C. or less, preferably 120 ° C. or more and 250 ° C. or less in an atmosphere such as air.

The time required for heat treatment is sufficient in the range of 0.5 to 10 hours, and usually 1 to 5 hours.

The tartan concentration in the catalyst obtained by the above method is 0.01 to 20 atoms (nm ² , preferably 0.5 to 9 atoms (nm ² ), which is 0.47 wt% / g on a carrier having a specific surface area of 100 m ² / g. Titanium is bound to silicon atoms via oxygen atoms, while hydroperoxides are coordinated to tartan atoms to activate them.

On the other hand, aryl chlorides have low reactivity of double bonds and low selectivity to epoxide because of the strong electronegativity of chlorine atoms. For example, in the case of epoxylation of arylchloride, the use of ethylbenzene hydroperoxide gives epichlorohydrin at 55% selectivity and only epichlorohydr at 8% selectivity in cumenehydroperoxide.

However, by using the catalyst of the present invention, it has been found that aryl chlorides are adsorbed on the surface of a suitable silanol group, thereby reacting at high selectivity and high selectivity. These epoxidation reactions occur at very low temperatures, and it is considered that arylchlorides adsorbed on the silanol groups and hydroperoxides serving titanium react with each other.

On the other hand, in a catalyst which is usually titanium-supported on silicon dioxide showing activity for epoxidation of prolene and calcined at a high temperature of about 800 ° C., only a low selectivity as mentioned above is given to epoxidation of aryl chlorides.

This work is evident by comparing the adsorption amounts of arylchloride with catalysts having various concentrations of silanol groups.

The result of the comparison with respect to the silica hydrogel carrier which has various silanol group concentration is shown below.

The carrier has a specific surface area of 370 m ² / g, average pore diameter of 140 kPa, adsorption conditions of adsorption temperature of 25 ° C., and adsorption pressure of 6 Torr. The SiOH radicals of the carrier were measured by thermogravimetric analysis TG / KTA and determined by the amount of heat loss.

The adsorption of aryl chloride to silanol is evident by the infrared spectrum of the adsorption state, which is shown in FIG. That is, as apparent from the relationship between the adsorption of aryl chloride to the T-20 catalyst and the infrared absorption spectrum of the SiOH group, the absorption attributed to Si-OH of 3500 to 3800 cm ^-1 changes according to the adsorption of aryl chloride. It can be seen that.

In the present invention, the reaction of reacting the alkylhydroperoxide with the aryl chlorides in the presence of a catalyst having a titanium and silanol group on the silicon dioxide carrier can be carried out by diluting with a solvent as necessary. Suitable solvents include those as unreacted raw materials for the production of hydroperoxides such as ethyl benzene and cumene, hydroperoxides such as combustion-based alkyl compounds, methylphenylcarbinol, dimethylphenylcarbinol, cyclohexanol or tert-butanol. It may be produced with oxide. The concentration of the hydroperoxide is not particularly limited, but 5 to 90% is usually used.

It is preferable that the ratio of aryl chlorides to hydroperoxide is excessive, and the yield improves by using 2 mol or more, more preferably 5 mol or more of aryl chlorides with respect to 1 mol of hydroperoxides normally. However, even if the molar ratio of acryl chlorides is raised too much, the yield reaches a limit, so economically, 50 moles or less is justified.

The reaction can be carried out in a batch reaction or a continuous reaction.

The catalyst can be used either in a suspended state or in a fixed bed state. The usage-amount of a catalyst is 0.01 weight% or more with respect to hydroperoxide, Preferably it is 0.05-30 weight%. Reaction temperature is 0-250 degreeC normally, Preferably it is 20-150 degreeC. If it is lower than 0 ° C, the reaction is slow, and if it exceeds 250 ° C, hydroperoxy decomposition occurs selectively. There is no restriction | limiting in particular in reaction pressure, What is necessary is just a condition which can maintain a reaction system in a liquid phase.

EXAMPLE

Hereinafter, embodiments of the present invention will be described in detail.

[Preparation of Catalyst]

2170 g of a 30% aqueous solution of JIS No. 3 soda silicate was mixed at 25 ° C. with 27% sulfur content, and reacted at pH 1.5 for 1.5 hours to obtain a silica sol, and then left to stand for 1.5 hours to gel. The gel was washed with ammonia hydrogen at PH 10.5 at 80 ° C., followed by repeated washing with water to remove Na content up to 0.05%. The gel was dried overnight at 150 ° C. to obtain silica hydrogel having a particle diameter of 30 to 120 mesh.

The silica hydrogel had a surface area of 300 M ² / g, an average pore diameter of 140 GPa, and the number of silanol groups on the surface was 6.0 particles / nm ^{2 as} a result of thermogravimetric analysis.

60 g of this silica hydrogel was added to a mixture of 120 ml of ethanol and 2.38 g of titanium tetrachloride, stirred for 30 minutes, impregnated with silica gel, and ethanol was distilled off under normal pressure, and then dried under reduced pressure at 100 ° C. and 3 Torr for 1 hour.

This had 0.42 atoms / nm ² of titanium supported on the surface of the carrier.

The catalyst prepared by the above method was used as it is or used by heating and baking for 2 hours at a predetermined temperature in an air stream. Firing temperature and surface silanol group temperature are as follows.

Example 1

12.0 g of one of the above catalysts, 128.5 g of aryl chlorides, and 30.5 g of cumene solution of 40% cumene hydroperoxide were added to a 300 ml stainless steel autoclave, and the mixture was reacted at 80 ° C for 5 hours.

Residual hydroperoxide concentration of the reaction mass was determined by iodine titration, cumene hydroperoxide conversion was calculated, and epichlorohydrin yield was calculated based on the analysis results by gas chromatography of the reaction mass.

Table 2 shows the results of the above reactions being performed on each of the catalysts A, B, C, and D.

Comparative Example 1

Reaction was performed about each of said catalysts E and F by the method similar to Example 1. The results are shown in Table 1.

TABLE 1

Example 2

12.0 g of one of the catalysts, 60 g of aryl chlorides, and 48 g of an ethylbenzene solution of butylbenzenehydroperoxide were added to a 200 ml stainless steel oatclave and reacted at 90 DEG C for 4 hours. The same analysis was conducted to find the conversion of ethylbenzene hydroperoxide and the yield of epichlorohydrin. The above reaction was performed for each of the catalysts A, B, and D. The results are shown in Table 2.

Comparative Example 2

The reaction was carried out for each of the catalysts E and F in the same manner as in Example 2. The results are shown in Table 2.

TABLE 2

Example 3

12.0 g of catalyst B, 120 g of aryl chloride, and 15 g of tert butanol solution of tert butylhydroperoxide were added to a 200 ml stainless steel oatclave and reacted at 80 DEG C for 4 hours, and epoxidation of aryl chloride was carried out. It was done. The results are shown in Table 3.

Comparative Example 3

In the same manner as in Example 3, the reaction results using the catalyst E are shown in Table 3.

TABLE 3

Example 4

12.0 g of catalyst B, 120 g of 2-methylaryl chloride, and 30 g of cumene solution of 40% cumene hydroperoxide were added to a 300 ml stainless steel autoclave, and the reaction pressure was 1.5 kg / cm ² at 80 ° C for 5 hours. It reacted in G. The results are shown in Table 4.

[Comparative Example 4]

In the same manner as in Example 4, the reaction results using the catalyst E are shown in Table 4.

TABLE 4

Example 5

12.0 g of catalyst B, 120 g of aryl chlorides and 120 g of a cyclohexane solution of 10% cyclohexyl hydroperoxide were added to a 300 ml stainless steel oatclave, and the mixture was reacted at 100 ° C for 6 hours. The results are shown in Table 5.

[Comparative Example 5]

In the same manner as in Example 5, the reaction results using the catalyst E are shown in Table 5.

TABLE 5

Example 6

12 g of catalyst B, 120 g of aryl chloride, and 30 g of cumene solution of 40% cumene hydroperoxide were added to a 300 ml four-necked flask, and reacted at 40 ° C. for 10 hours at atmospheric pressure.

When the reaction mass was analyzed, the cumene hydroperoxide conversion rate was 93% and epichlorohydrin yield 69%.

According to the method of the present invention, epichlorohydrin can be produced from arylchlorides at low temperature with high conversion and selectivity by using an industrially available alkylhydroperoxide as an oxidizing agent. The prize is very valuable.

Claims (4)

In the presence of a titanium atom bonded to a silicon dioxide carrier via an oxygen atom, and a catalyst having 1/1 square nanometer or more of silanol groups on the same carrier, epitaxial reaction is carried out by reaction of arylchlorides with alkylhydroperoxides. Method for producing chlorohydrins. The method for producing epichlorohydrin according to claim 1, wherein the catalyst is a catalyst which has been subjected to a catalytic treatment of a silica gel e titanium compound and then heated at 100 to 500 ° C. under a non-reducing gas atmosphere. The method for producing epichlorohydrin according to claim 1, wherein the catalyst has a titanium concentration of 0.01 to 20 atoms / square nanometer. The method for producing epichlorohydrin according to claim 1, wherein the alkylhydroperoxide is cumene hydroperoxide, ethylbenzenehydroperoxide, tert-butylhydroperoxide or cyclohexylhydroperoxide.

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