KR20020074578A - Method for Preparing 2,2’-bis(4-hydroxycyclohexyl)propane - Google Patents

Abstract

PURPOSE: Provided is a method for producing a hydrogenated bisphenol A, which can maximally inhibit the generation of byproduct resulting from dehydration, and which can be easily applied to continuous reaction using a fixed bed reactor and thus can economically produce the hydrogenated bisphenol A. CONSTITUTION: The method, which comprises hydrogenating a bisphenol-A(4,4'-dihydroxydiphenylpropane) to produce a hydrogenated bisphenol-A(2,2-bis(4-hydroxycyclohexyl)propane), is characterized in that bisphenol A, which is dissolved in solvent in the presence of catalyst, is catalytically hydrogenated. The catalyst is formed by supporting ruthenium on silica carrier having acid strength of 10% or less. The acid strength of catalyst is defined as the conversion of 2-propanol when 1 g of the catalyst is introduced into a fixed bed reactor, and gas consisting of 5 vol% of 2-propanol and 95 vol% of helium is reacted in the reactor by passing through the reactor at a rate of 50 ml/minute(based on helium flow rate).

Description

Method for preparing hydrogenated bisphenol-A {Method for Preparing 2,2′-bis (4-hydroxycyclohexyl) propane}

The present invention relates to a process for preparing hydrogenated bisphenol-A. More specifically, the present invention provides a method for producing high yield hydrogenated bisphenol-A by catalytic hydrogenation of bisphenol-A in the presence of a ruthenium-supported catalyst on a silica support having an acid activity index of 10% or less. It is about.

Hydrogenated bisphenol-A, ie 2,2-bis (4-hydroxycyclohexyl) propane, is a useful material as a raw material for polymer polymerization. For example, the polyester resin produced by polycondensing hydrogenated bisphenol-A with dibasic acids such as phthalic acid and maleic acid has excellent heat resistance and moisture resistance. In addition, the epoxy resin prepared by reacting hydrogenated bisphenol-A with epichlorohydrin has excellent electrical properties and does not contain aromatic rings, and thus has low yellowing, so that it can be used where weather resistance is required. It has the advantage of excellent operability.

The addition of hydrogen to the aromatic rings of bisphenol-A using metal supported catalysts to produce hydrogenated bisphenol-A has been studied by several researchers for decades, mainly using improved metal supported catalysts or specific reactions. It is reported that the use of a solvent can improve the hydrogenated bisphenol-A yield and / or reaction rate.

As the catalyst used in the above-mentioned hydrogenation reaction, as is generally known, a Group VIII metal such as palladium, platinum, nickel, ruthenium, etc. is used. In some cases, the metal itself is used as a catalyst, but most of them are economical. The metal is used by being dispersed / supported on a support. At this time, the support serves to disperse the metal widely by using a large surface area and to improve physical properties such as thermal and mechanical stability that are difficult to obtain only with the metal. Examples of materials generally used for this purpose include silica, alumina, silica-alukina, Zeolite, activated carbon and the like.

As mentioned above, examples of the prior art using metal catalysts in bisphenol-A catalytic hydrogenation are as follows:

Japanese Patent Laid-Open No. 61-260034 uses 10 to 100% by weight of alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide as a reaction accelerator in the presence of a Raney-nickel catalyst. A method of hydrogenating bisphenol-A is disclosed. In the invention, the hydrogen pressure was in the range of 40 to 60 kg / cm 2, and the hydrogenation reaction temperature was in the range of 120 to 220 ° C.

Japanese Patent Application Laid-Open No. 53-119854 prepares 4,4'-isopropyridenecyclohexanol in high purity using Raney-nickel containing at least one metal selected from the group consisting of iron, chromium and lead as a catalyst. A method of doing this is disclosed.

On the other hand, US Patent No. 4,885,409 discloses a process for hydrogenating bisphenol by using a palladium-supported activated carbon catalyst, a bulk reaction or a reaction in a solvent, wherein the content of the trans-trans isomer in the product is 55 It is stated to be at least% by weight and the reaction selectivity is at least 99% by weight.

Similarly, Japanese Patent Laid-Open No. 45-35300 uses a catalyst carrying rhodium on a support, and Japanese Patent Laid-Open No. 53-119855 uses a ruthenium-supported activated carbon catalyst and 4,4'- in the presence of isobutanol or isopropanol. A method for preparing isopropyridanecyclohexanol is disclosed.

In addition, Japanese Patent Laid-Open No. 6-9461 discloses a method of hydrogenating bisphenols such as bisphenol-A using a ruthenium catalyst in a C ₄ or higher secondary alcohol (eg, octanol) solvent. Ruthenium is supported on alumina, silica, titania, etc. and used as a catalyst. U.S. Pat.No. 5,936,126 discloses an active metal that reacts an organic compound using at least one of ruthenium or a bond of ruthenium with Group IB, Group B and Group B metals on a support, wherein the support is activated carbon, silicon carbide, Alumina, silica, titania, zirconia, magnesium oxide, zinc oxide and the like are used, the average pore diameter is at least 50 nm, the BET surface area is 30 m 2 / g or less, and the amount of the active metal is 0.01 to the total weight of the catalyst. A point having a range of 30% by weight is disclosed. U.S. Patent No. 5,942,645 also describes a process for hydrogenating aromatic compounds using a ruthenium supported catalyst, wherein activated carbon, silicon carbide, alumina, silica, titania with an average pore diameter of at least 0.1 μm and a surface area of 15 m 2 / g or less , Macroporous supports such as zirconia, magnesium oxide, and zinc oxide are used.

Most recently, a process has been proposed for reacting a compound having an aromatic ring with hydrogen in the presence of a noble metal Raney catalyst comprising at least 50% by weight of ruthenium as active ingredient of the catalyst as disclosed in US Pat. No. 6,018,048.

On the other hand, in the BPA contact hydrogenation reaction, BPA may be reacted as it is without using a solvent, but in most cases, it is reacted in the presence of a solvent. In this connection, as described in Japanese Patent No. 6-09461, there is also a claim that the reaction rate is improved when using an alcohol solvent having a C ₈ or higher as compared to the case where an alcohol having a low carbon number is used.

However, despite many researches on the hydrogenation reaction of BPA, the development of steadily related technologies until recently is a testament to the fact that there are still many shortcomings in the industrial use of these technologies, and the prior art is described in the specification. According to the results of reproducing experiments, it was confirmed that in most cases, it is difficult to obtain high economic results in consideration of the price of the catalyst, the reaction yield of hydrogenated bisphenol-A, the operation time, and the like. There was a limit.

In particular, the inventors of the present invention conducted a study to investigate the cause of the decrease in the yield of the hydrogenated bisphenol-A reaction. As a result, when the hydrogenation reaction of the bisphenol-A is carried out using a metal supported catalyst, During the hydrogenation reaction, one or two of the two hydroxyl functional groups contained in the hydrogenated bisphenol-A were dehydrated to produce an undesirable substance, which was found to be related to the acid strength of the catalyst support itself. That is, as the acid strength of the catalyst support increases, dehydration reaction is promoted during the hydrogenation reaction, thereby lowering the reaction yield of hydrogenated bisphenol-A.

Dehydration is one of the typical acid catalyzed reactions (the chemistry of catalytic hydrocarbon conversions, Herman Pines, Academic press, 2-3 pages, 1981). It is well known that most of the supports used in the prior art for supporting metals, such as alumina and silica-alumina except activated carbon and silica, also have a catalytic function as a solid acid (introduction to catalysts, transfer agents, Hallymwon, p260). , 1992). Therefore, the use of these solid acids as a support causes a dehydration reaction of the hydrogenated bisphenol-A due to the acid function during the hydrogenation reaction. Therefore, in the BPA hydrogenation reaction, in order to suppress the dehydration reaction and to increase the yield of hydrogenated bisphenol-A, it is important to select a support having a weak acid strength and carry the group VIII metal thereto. However, in the prior art, no example was found to identify the importance of the acid strength of the support itself and the direct cause of the side reactions.

In contrast, the present inventors use weakly acidic silica having an acid strength index of 10% or less as a catalyst support having high mechanical strength, withstanding high temperature firing, easy regeneration and easy to apply to commercial processes, and a catalyst carrying ruthenium thereon. When the bisphenol-A catalytic hydrogenation reaction is used, side reactions such as dehydration can be suppressed as much as possible, thereby producing hydrogenated bisphenol-A with high efficiency and high yield.

Accordingly, an object of the present invention is to provide a method for producing hydrogenated bisphenol-A with high efficiency and high yield by reducing the dehydration reaction due to the acid function of the support during the hydrogenation reaction.

Another object of the present invention is to provide a method for economically producing hydrogenated bisphenol-A by hydrogenating bisphenol-A in a relatively simple manner.

In order to achieve the above object, the method for producing 2,2-bis (4-hydroxycyclohexyl) propane according to the present invention is dissolved in a solvent in the presence of a catalyst having ruthenium supported on a silica support having an acid strength index of 10% or less. Catalytically hydrogenating 4,4'-dihydroxydiphenylpropane, wherein the acid strength index is charged with 1 g of catalyst in a fixed bed reactor and 5 vol% of 2-propanol and 95 vol at a temperature of 250 ° C. A gas consisting of% helium is defined as the conversion rate of 2-propanol when reacted with a rate of 50 ml per minute based on the helium flow rate.

The above and other objects of the present invention can be achieved by the following description.

The support used in the present invention is a silica adjusted to an acid strength index of 10% or less, and has an acid strength index of 10 such as pyrogenic silica, which is known under the trade names of natural silica, synthetic silica, silica gel, aerosil, and carbosil. If it is less than%, it can be used as a support without any restriction. In the case where silica contains a small amount of impurities such as aluminum or zirconium, the acid strength is greatly increased. Therefore, the silica having an acid strength index of less than 10% must be used to suppress the dehydration reaction during the hydrogenation reaction. At this time, it is preferable that the surface area of a silica is 50-500 m <2> / g.

In order to numerically express the acid strength of a solid acid, various methods have been proposed but are not generally applicable in all cases. U.S. Patent 5,773,677 uses the following method to quantify the acid strength of a metal supported catalyst support. That is, when 1 g of catalyst is placed in a fixed bed reactor and reacted with a gas of 5 vol% 2-propanol and 95 vol% helium at a temperature of 250 ° C. at a rate of 50 ml / min based on the helium flow rate, 2- The conversion rate of propanol defines the acid strength index. In the above patent, the above-mentioned method is used as a measure for selectively using a support having particularly strong acid strength, but according to the results of the inventors' experiment, since the reaction temperature is high at 250 ° C, most solid acids including alumina are used. The acid strength index of the support is 100%, making it difficult to distinguish a solid acid having a strong acid strength. In addition, in the case of a basic support, 2-propanol may be converted to acetone and the like, so that the acid strength index may be about 40%. For the catalyst requiring a strong acid strength, the above-described acid strength measuring method may not be suitable. . However, pure silica supports and some activated carbons show very low activity of the support itself with an acid strength index of less than 10% even when using the aforementioned method. In the present invention, since the low activity support is used to reduce the side reactions during the hydrogenation reaction, the acid strength index evaluation method described in US Pat. No. 5,773,677 is suitable for selecting a support having low acid strength. The above method is applied to evaluate the mountain strength index. In the case of the catalytic hydrogenation reaction of bisphenol-A known in the prior art, all of the aluminas and the like used as a support had an acid strength index of 90% or more evaluated by the aforementioned method. There are many side reactions due to dehydration during the hydrogenation of A. Among the supports having a low acid strength index of 10% or less, the activated carbon used in the related art has a weak mechanical strength compared to silica or alumina as the main component of carbon, and burns in a high temperature oxygen atmosphere. In particular, it is difficult to apply the catalyst which has been calcined to be removed or deactivated by high temperature calcining, and thus it is difficult to apply to a continuous reaction using a fixed bed reactor.

The ruthenium catalyst used in the present invention is prepared by dissolving ruthenium in a salt state in water and then supporting it on silica according to a method generally known in the art. The catalyst carrying the ruthenium salt as described above is calcined at 300 to 600 ° C. in air to be decomposed and stored, and is preferably used after reduction to a temperature of 100 to 500 ° C. in a reducing agent atmosphere such as hydrogen before the hydrogenation reaction. Do. Ruthenium salts that can be used to prepare the catalyst of the present invention include ruthenium chloride, ruthenium nitrosyl nitrate, ruthenium acetylacetonate, and the like, but are not necessarily limited to the salt form. . As described above, the content of ruthenium supported on the silica support is preferably 0.1 to 20% by weight based on the total weight of the catalyst, and the shape of the catalyst is not particularly limited.

Using the catalyst prepared as described above, the process for hydrogenating bisphenol-A is as follows:

First, the amount of the supported ruthenium catalyst is sufficient if the weight ratio of the metal ruthenium to the raw material bisphenol-A is in the range of about 0.01 to 0.5% by weight in the case of the batch reaction, and at the weight space velocity of the bisphenol-A in the case of the continuous reaction. The range of about 0.01-5 h <^-1> is suitable. The amount of catalyst used and the weight space velocity depend on the economics of the reaction. In the case of batch reaction, if the amount of the catalyst is too small, the time required for the completion of the reaction is long. The cost of the catalyst increases, resulting in lower economic efficiency. In the case of the continuous reaction, if the weight space velocity is too fast, the conversion is not performed, and if the weight space velocity is too slow, there is a problem in that economic efficiency is lowered due to an increase in operating cost.

Since bisphenol-A exists in a solid state at room temperature, it is preferable to dissolve bisphenol-A in an appropriate solvent in order to increase the fluidity of the reactants, increase the transport convenience, and improve the reaction efficiency, especially when using a continuous reactor. As the solvent used for this purpose, for example, alcohols and acetates can be used, and the solvent is used in an amount of about 0.5 to 20 times the weight of the bisphenol-A as a raw material.

The temperature of the hydrogenation reaction carried out in the present invention is preferably about 50 to 250 ℃, the reaction pressure is preferably adjusted in the range of 5 to 150 kg / cm 2. In addition, the ratio of the amount of bisphenol-A reacted to hydrogen is 6: 1 to 600: 1 on a molar basis, preferably 6: 1 to 30: 1.

On the other hand, the hydrogenation process of the present invention can be carried out by a continuous or batch. However, continuous reaction using a tubular fixed bed reactor is particularly preferable in view of overall operating costs, reaction efficiency, and the like. Continuous reactions using tubular fixed bed reactors are used by shaping the catalyst in an appropriate size, in particular in the form of pellets, depending on the length and diameter of the reactor. Such fixed bed reactor designs are commonly known in the art. On the other hand, in the case of a batch reaction, it is preferable to use a catalyst in powder form.

The present invention may be further embodied by the following examples, which illustrate the present invention and are not intended to limit the protection scope of the present invention.

Example 1

After filling a 1 mm by weight ruthenium-supported silica catalyst, which was formed into pellets of 3 mm size as a catalyst, into a tubular reactor made of stainless steel with a capacity of 80 cc with a diameter of 10 mm, hydrogen was fed at a rate of 20 cc / min and 400 It heated up to ° C and performed reduction. After the reduction, the amount of hydrogen was adjusted to 6 times the moles of bisphenol-A added, and the temperature and the reaction pressure of the reactor were maintained at 150 ° C. and 100 kg / cm 2, respectively. Then, the reaction was started while adding the reaction raw materials at a weight space velocity of 2h ^-1 . As a reaction raw material, 20 wt% of bisphenol-A dissolved in 2-propanol was used, and the reaction product was analyzed by gas chromatography with a flame ionization detector. As a result of the analysis, the average conversion of bisphenol-A was 100% for 40 hours after the reaction, and the average selectivity of hydrogenated bisphenol-A was 96%. In addition, there was no activity deterioration even when the reaction was continued for up to 500 hours.

Examples 2 to 3

A catalyst was prepared by crushing a silica support having an acid strength index of 10% or less to 100 mesh and 120 mesh sizes, respectively, and then carrying ruthenium such that ruthenium became 1% by weight of the total catalyst weight. 10 g of BPA, 40 g of 2-propanol and 0.5 g of the catalyst were added to an 80-cc autoclave reactor, and reacted for 2 hours with stirring at a reaction temperature of 180 ° C. and a reaction pressure of 40 kg / cm 2. The reaction product was analyzed by gas chromatography with a flame ionization detector, and the results of the reaction experiment according to the acid strength index of each silica support are summarized in Table 1 below.

Comparative Examples 1 to 3

The reaction was carried out in the same manner as in Example 1, except that the catalyst prepared by supporting ruthenium to be 1% by weight on different supports having an acid strength index of 10% or more was used. The results are summarized in Table 1 below.

Comparative Example 4

The catalyst was prepared by crushing alumina (product name: SA3177), Norton's commercial product, to a size of 100/120 mesh and carrying ruthenium so that ruthenium became 2% by weight of the total catalyst weight. 10 g of BPA, 40 g of 2-propanol, and 0.5 g of the catalyst were added to an 80-cc autoclave reactor, and the mixture was reacted for 2 hours under stirring at a reaction temperature of 180 ° C. and a reaction pressure of 40 kg / cm 2. The reaction product was analyzed by gas chromatography with a flame ionization detector, and the results of the reaction experiment according to the acid strength of each catalyst support are shown in Table 1 below.

Support Mountain Century Index (%) Reaction yield (%) Example 2 Silica A 2.3 95.5 Example 3 Silica B 1.9 95.8 Comparative Example 1 Silica C 95.1 87.2 Comparative Example 2 SA 3177 100 83.5 Comparative Example 3 SA 6273 100 82.2 Comparative Example 4 SA 3177 100 84.2

As can be seen from the results of Examples 1 and Table, in the case of a catalyst having ruthenium supported on a support whose acid strength index was adjusted to 10% or less as in Examples 1 to 3, ruthenium was supported on a support having a higher acid strength index than this. It was found that the reaction yield was significantly improved compared to the catalyst. In particular, according to the results of Comparative Example 1, it was confirmed that even when silica was used as a support, an improvement in reaction yield could not be obtained unless the acid intensity index was adjusted to 10% or less.

As described above, in the case of producing the hydrogenated bisphenol-A according to the present invention it is possible to suppress the side reactions generated by the dehydration reaction to the maximum, and in particular, because it can be easily applied to the continuous reaction using a fixed bed reactor economically It has the advantage of producing hydrogenated bisphenol-A.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (7)

In a method for producing hydrogenated bisphenol-A (2,2-bis (4-hydroxycyclohexyl) propane) by hydrogenating bisphenol-A (4,4'-dihydroxydiphenylpropane), the acid strength index is Catalytic hydrogenation of bisphenol-A dissolved in a solvent in the presence of a ruthenium-supported catalyst on a silica support of 10% or less, wherein the acid strength index is charged with 1 g of catalyst in a fixed bed reactor and 5 volumes at a temperature of 250 ° C. 2,2-bis (4), characterized by the conversion rate of 2-propanol when a gas consisting of% 2-propanol and 95 volume% helium is passed at a rate of 50 ml / min based on the helium flow rate. Method for preparing hydroxycyclohexyl) propane. The 2,2-bis (4-hydroxycyclohexyl) according to claim 1, wherein the silica is selected from the group consisting of natural silica, synthetic silica and pyrogenic silica, and has a surface area of 50 to 500 m 2 / g. ) Propane manufacturing method. The method of claim 1, wherein the ruthenium content in the catalyst is 0.1 to 20% by weight based on the total weight of the catalyst. The 2,2-bis (4-hydride) according to claim 1, wherein when the hydrogenation reaction is a batch reaction, the weight ratio of the metal ruthenium to bisphenol-A used as a raw material is in the range of 0.01 to 0.5 wt%. Process for the preparation of oxycyclohexyl) propane. 2. The 2,2-bis (4-hydroxycyclo) according to claim 1, wherein the weight space velocity of bisphenol-A used as a raw material is 0.01 to 5 h ^-1 when the hydrogenation reaction is a continuous reaction. Hexyl) Propane. 2. The 2,2-bis (4-hydroxycyclohexyl) propane according to claim 1, wherein the solvent is an alcohol or an acetate and is used in an amount of 0.5 to 20 times by weight of bisphenol-A. Manufacturing method. The method for preparing 2,2-bis (4-hydroxycyclohexyl) propane according to claim 1, wherein the ratio of the amount of bisphenol-A to hydrogen is 6: 1 to 600: 1 on a molar basis. .