Title of Invention

"PROCESS FOR PRODUCING BISPHENOL A "

Abstract

In the present invention, there is provided a process for producing bisphenol A according to the present invention includes a reaction step of flowing a raw phenol material and a raw acetone material through a vertical type fixed bed reactor filled with an ion exchange resin catalyst to obtain a bisphenol A-containing reaction solution, wherein when an absolute value of a temperature difference (AT) between the reaction solution located at any position of a portion of an ion exchange resin catalyst layer formed in the reactor which portion extends from an outlet of the ion exchange resin catalyst layer up to 2 0% of a height of the catalyst layer, and the reaction solution located in an outlet of the vertical type fixed bed reactor, is 1.0° to 5.0C, at least a part of the ion exchange resin catalyst is fluidized. By the above process, it can be attained to stably produce bisphenol A for a long period of time while being free from local deterioration of a catalyst by eliminating occurrence of channeling of a reaction solution flowing through an ion exchange resin catalyst filled in a reactor.

Full Text

SPECIFICATION PROCESS FOR PRODUCING BISPHENOL A AND VERTICAL TYPE FIXED BED REACTOR TECHINCAL FIELD The present invention relates to a process for producing bisphenol A and a vertical type fixed bed reactor, and more particularly, to a process for producing bisphenol A which is capable of eliminating channeling of a reaction solution flowing through an ion exchange resin catalyst filled in a reactor, preventing local deterioration of the catalyst, and stably producing the bisphenol A product for a long period of time, and a vertical type fixed bed reactor used therein. RELATED ARTS Bisphenol A has been usually produced by reacting phenol and acetone with each other in the presence of an acidic catalyst. As the acidic catalyst, there is generally used a sulfonic acid-type cation exchange resin from the standpoints of a high reaction rate and a good selectivity thereof. The reaction is usually conducted in a continuous manner by flowing a raw phenol material and a raw acetone material in a down-flow through a vertical type fixed bed reactor filled with the sulfonic acid-type cation exchange resin catalyst. After the reaction is conducted for a predetermined period of time, an operation of the reactor was stopped to wash the deteriorated catalyst or replace the catalyst with a new one. The sulfonic acid-type cation exchange resin catalyst is deteriorated by various factors, and, therefore, various measures have been studied to solve the problems. For example, there are known the method of controlling a concentration of methanol contained in the raw acetone material which causes deterioration of the catalyst, to not more than a predetermined level (e.g., refer to Japanese Patent Application Laid-open (KOKAI) No. 2005-162742), the method of removing impurities causing deterioration of a catalyst from a mother liquor obtained by removing low-boiling components from a reaction solution and then subjecting the solution to crystallization and separation treatments, upon reusing the mother liquor (e.g., refer to Japanese Patent Publication (KOKOKU) No. 49-48319 (1974) and Japanese Patent Application Laid-open (KOKAI) Nos. 1-230538 (1989) and 5-331088 (1993)). However, even in these methods, the sulfonic acid-type cation exchange resin catalyst used therein tends to be inevitably deteriorated upon the reaction, resulting in a poor conversion of acetone. SUMMARY OF THE INVENTION SUBJECT TO BE SOLVED BY THE INVENTION As a result of the present inventors' studies on deterioration of the catalyst and poor acetone conversion, it becomes apparent that channeling of the reaction solution is caused in the catalyst layer, whereby the condition of the reaction solution flowing through the catalyst layer is gradually changed. More specifically, it becomes apparent that the reaction solution flowing through the catalyst layer is not uniformly flowed through a whole portion of the catalyst layer in the reactor, but flow paths that the reaction solution flows more easily are formed and the flow rate of such paths is increased to form so-called channeling. For this reason, a large load is applied to the catalyst being present in and around the flow path undergoing a large flow rate of the reaction solution, resulting in accelerated deterioration of the catalyst. Further, the accelerated deterioration of the catalyst being present in and around the flow path undergoing a large flow rate of the reaction solution leads to increase in flow rate of the reaction solution having a low acetone conversion at such a portion, so that the acetone conversion of the reaction solution flowing through a whole part of the catalyst layer also tends to be lowered. Therefore, it becomes apparent that unless such a basic problem that the catalyst is locally deteriorated due to channeling of the reaction solution flowing through the catalyst layer, is eliminated, the above conventional problems such as deterioration of the catalyst and poor acetone conversion cannot be solved. The present invention has been made to solve the above conventional problems. An object of the present invention is to provide a process for stably producing bisphenol A for a long period of time which is free from local deterioration of a catalyst by eliminating occurrence of channeling of a reaction solution flowing through an ion exchange resin catalyst filled in a reactor, as well as a vertical type fixed bed reactor used therein. MEANS FOR SOLVING THE SUBJECT As a result of the present inventors' earnest study for solving the above conventional problems, it has been found (1) that under a stable condition at an initial stage of the reaction, there is substantially no difference between a temperature of a reaction solution located at any position of a portion of an ion exchange resin catalyst layer which portion extends from an outlet of the ion exchange resin catalyst layer up to 20% of a height of the catalyst layer, and a temperature of the reaction solution located in an outlet of a reactor; (2) that when a flow rate of the reaction solution flowing through a specific flow path is increased or decreased owing to occurrence of channeling of the reaction solution in the catalyst layer, a temperature of the reaction solution located at a portion of the catalyst layer where the channeling is caused, is decreased or increased as compared to a temperature of the reaction solution located at the outlet of the reactor; and (3) that when an absolute value of a temperature difference between the reaction solution located at the flow path where the flow rate of the reaction solution is large and the reaction solution located in the outlet of the reactor is not less than a predetermined value, occurrence of channeling of the reaction solution through the catalyst layer can be avoided and the catalyst can be prevented from suffering from local deterioration by allowing at least a part of the ion exchange resin catalyst to be fluidized. The present invention has been attained on the basis of the above findings. That is, to accomplish the aims, in a first aspect of the present invention, there is provided a process for producing bisphenol A comprising a reaction step of flowing a raw phenol material and a raw acetone material through a vertical type fixed bed reactor filled with an ion exchange resin catalyst to obtain a bisphenol A-containing reaction solution, in which when an absolute value of a temperature difference (AT) between temperature of the reaction solution located at any position of a portion of an ion exchange resin catalyst layer formed in the reactor which portion extends from an outlet of the ion exchange resin catalyst layer up to 20% of a height of the catalyst layer, and temperature of the reaction solution located in an outlet of the vertical type fixed bed reactor, is 1.0 to 5.0°C, at least a part of the ion exchange resin catalyst is fluidized. In a second aspect of the present invention, there is provided a vertical type fixed bed reactor filled with an ion exchange resin catalyst, which has such an ability that a temperature of a reaction solution is measurable at least two positions of a portion of an ion exchange resin catalyst layer formed therein which portion extends from an outlet of the ion exchange resin catalyst layer up to 2 0% of a height of the catalyst layer. EFFECT OF THE INVENTION In the process for producing bisphenol A according to the present invention, channeling of a reaction solution flowing through an ion exchange resin catalyst filled in a reactor can be prevented, so that the catalyst can be prevented from suffering from local deterioration, thereby enabling bisphenol A to be stably produced for a long period of time. BRIEF DESCRIPTION OF THE DRAWING Fig. 1 is an explanatory view of a vertical type fixed bed reactor used in Example 1 of the present invention. EXPLANATION OF REFERENCE NUMERALS 1: Reactor; 2: Heat-insulating material; 3: Catalyst supporting member; 4: Catalyst layer; 5: Thermocouple; 6: Thermocouple; 7: Pump; 51: Measuring point 0; 52: Measuring point 1; 52: Measuring point 2 PREFERRED EMBODIMENT FOR CARRYING OUT THE INVENTION The present invention is described in detail hereinunder. The following descriptions are merely concerned with a typical example of preferred embodiments of the present invention, and it is therefore not intended to limit the scope of the present invention thereto. The process for producing bisphenol A according to the present invention include at least a reaction step of flowing a raw phenol material and a raw acetone material through a vertical type fixed bed reactor filled with an ion exchange resin catalyst to obtain a bisphenol A-containing reaction solution. In the reaction step of the present invention, there is used a vertical type fixed bed reactor filled with an ion exchange resin as a catalyst. A raw phenol material and a raw acetone material fed to the vertical type fixed bed reactor are reacted with each other under such a condition that phenol is used in a stoichiometrically excessive amount relative to acetone. The molar ratio of phenol to acetone (phenol/acetone) is usually 3 to 30 and preferably 5 to 20. The liquid hourly space velocity of a mixture of the raw materials fed to the reactor is usually 0.2 to 50/h; the reaction temperature is usually 30 to 120°C, preferably 55 to 100°C; and the reaction pressure is usually from normal pressure to 600 kPa. The above raw phenol material means a raw material containing phenol as a main component. The content of phenol in the raw phenol material is usually not less than 50% by weight, preferably not less than 70% by weight and more preferably not less than 80% by weight. Pure phenol may be used as the raw phenol material of the present invention. The raw phenol material may also contain, in addition to phenol, other compounds such as bisphenol A, a 2,4-isomer of bisphenol A, chroman, trisphenol, isopropenyl phenol and cyclic dimers thereof. Also, a mother liquor separated in a recovery step of recovering bisphenol A, a reaction solution treated in an impurity treating step, etc., may be recycled individually directly or in the form of a mixed solution thereof. The above raw acetone material means a raw material containing acetone as a main component. The content of acetone in the raw acetone material is usually not less than 50% by weight, preferably not less than 70% by weight, more preferably not less than 90% by weight and still more preferably not less than 95% by weight. Pure acetone may be used as the raw acetone material of the present invention. The raw acetone material may also contain impurities such as water. Acetone separated and recovered in an acetone recycling step may be recycled directly or in the form of a mixed solution thereof with pure acetone. The ion exchange resin as the catalyst is preferably a strong acid cation exchange resin such as sulfonic acid-type cation exchange resin. The catalyst may be usually used together with a co-catalyst such as a sulfur-containing compound. In this case, there may be adopted the method of feeding a sulfur-containing compound such as hydrogen sulfide and an alkyl thiol together with the raw phenol material or the raw acetone material (method 1), or the method of using an ion exchange resin to which a sulfur-containing compound is previously bonded, as the catalyst (method 2). Examples of the alkyl thiol used in the method 1 may include methane thiol, ethane thiol and propane thiol. In the method 2, there is preferably used a strong acid cation exchange resin partially modified with the sulfur-containing amine compound. Examples of the sulfur-containing amine compound may include 2-(4-pyridyl)ethane thiol, 2-mercaptoethyl amine, 3-mercaptopropyl amine, N,N-dimethyl-3-mercaptopropyl amine, N,N-di-n-butyl-4-mercaptobutyl amine and 2,2-dimethyl thiazoline which are generally used as a co-catalyst for synthesis of bisphenol A. There is more preferably used such an ion exchange resin catalyst in which usually 2 to 30 mol% and preferably 5 to 20 mol% of an acid group in the acid ion exchange material (sulfonic acid group in the case of the sulfonic acid type ion exchange resin) is modified with the sulfur-containing amine compound. As described in the above second aspect of the present invention, the vertical type fixed bed reactor used in the process for producing bisphenol A according to the present invention is characterized by having such an ability that a temperature of the reaction solution is measurable at least two positions of a portion of the ion exchange resin catalyst layer formed therein which portion extends from an outlet of the ion exchange resin catalyst layer (a most downstream portion thereof in the case of a down-flow) up to 20% of a height of the catalyst layer. In the present invention, the term "outlet of the ion exchange resin catalyst layer" means a portion where the reaction solution passed through the catalyst layer is discharged. For example, in case of the following Example 1, "outlet of the ion exchange resin catalyst layer" is a contacting surface of catalyst supporting member (reference numeral 3 in Fig. 1) and catalyst layer (reference numeral 4 in Fig. 1). Examples of the temperature-measuring apparatus used in the reactor may include a thermocouple thermometer, etc. The temperature-measuring positions of the reaction solution fed, for example, in case of a down-flow is preferably two positions including a central portion of the catalyst layer and a downstream-side portion of a catalyst layer-supporting member, and more preferably such positions including the central portion of the catalyst layer, surrounding portions of the central portion of the catalyst layer, a conduit portion disposed on a downstream side of the catalyst layer-supporting member, etc. Further, the temperature of the reaction solution is preferably measured not only at positions in a horizontal direction of the catalyst layer, but also at plural positions in a height direction of the catalyst layer, since it can be recognized by the measurement that the change in temperature of the reaction solution in a flow direction thereof does not show a simple increase. However, the thermometer is preferably disposed in the catalyst layer so as not to cause channeling therein. Meanwhile, the vertical type fixed bed reactor of the present invention serves for measuring the change in temperature of the reaction solution in the catalyst layer as described above and, therefore, is preferably a heat-insulating type reactor. Under the condition capable of conducting the above temperature measurement, the raw phenol material and the raw acetone material are flowed through the vertical type fixed bed reactor filled with the ion exchange resin catalyst, thereby obtaining a bisphenol A-containing reaction solution. At an initial stable stage of the reaction, there occurs substantially no difference between the temperature of the reaction solution located at any position of a portion of the ion exchange resin catalyst layer which portion extends from an outlet of the ion exchange resin catalyst layer up to 20% of a height of the catalyst layer, and the temperature of the reaction solution located at an outlet of the reactor. However, with the elapse of the operation time, channeling of the reaction solution is caused in the catalyst layer, so that a load applied to the catalyst located in and around the flow path where a flow rate of the reaction solution is large, is increased. For this reason, the activity of the catalyst located in such a portion is deteriorated, and the temperature thereof is lowered as compared to that in a portion of the reaction solution other than the above large flow rate portion. Also, in the portion where the flow rate of the reaction solution is low, since a load applied to the catalyst is small, the activity of the catalyst becomes high, so that the temperature of the reaction solution is increased. In the production process of the present invention, when an absolute value of a temperature difference (AT) between the reaction solution located at any position of a portion of the ion exchange resin catalyst layer formed in the reactor which portion extends from an outlet of the ion exchange resin catalyst layer up to 20% of a height of the catalyst layer, and the reaction solution located in an outlet of the vertical type fixed bed reactor, is 1.0 to 5.0°C, at least a part of the ion exchange resin catalyst is fluidized. With the fluidization of a part of the ion exchange resin catalyst, the reaction solution is prevented from suffering from channeling in the catalyst layer, so that before the catalyst is deteriorated, the load applied to the catalyst is returned to a stable condition at an initial stage of the reaction, resulting in prolonged life of the catalyst. To fluidize at least a part of the ion exchange resin catalyst when the absolute value of a temperature difference (AT) being less than 1.0°C, of course, is possible. However, it is possible to prevent the deterioration of catalyst under ordinary operation condition by fluidizing at least a part of the ion exchange resin catalyst when the absolute value of temperature difference (AT) being less than 1.0°C, and further, frequent fluidizations of at least a part of the ion exchange resin catalyst are not preferable in view of stable operation and production efficiency. To fluidize at least a part of the ion exchange resin catalyst when the absolute value of temperature difference (AT) being more than 5.0°C, although some recovery effect of conversion of acetone may be expected, the catalyst already has been deteriorated and it is difficult to sufficiently recover the catalyst activity compared with the production efficiency at the initial stage of operation. Preferable range of the above absolute value of temperature difference (AT) is 1.5 to 4.0°C. The method of fluidizing a part of the ion exchange resin catalyst is not particularly limited. For example, there may be used the method of feeding a liquid in an up-flow through the down-flow vertical type fixed bed reactor (reverse washing method), the method of fluidizing the catalyst layer by a mechanical means, e.g., by using a stirrer or an apparatus capable of applying vibration to the catalyst layer, etc. Among these methods, the reverse washing method is preferred because this method allows the catalyst layer as a whole to be uniformly fluidized without installation of any additional equipment. The liquid to be fed in an up-flow through the vertical type fixed bed reactor is not particularly limited, and there may be used any liquids capable of fluidizing the catalyst such as water and phenol. Among these liquids, preferred are the raw phenol material and pure phenol. Fig. 1 shows a reactor used in the below-mentioned Example 1 and a flow diagram therethrough. An example of the above reverse washing method is explained by referring to Fig. 1. Under a normal operation mode, valves 81 and 82 are opened and valves 83 and 84 are closed, whereby a raw phenol material and a raw acetone material are fed to a reactor 1 through lines 91 and 92 using a pump 7. In the reactor 1, a catalyst layer 4 having a height 1 is formed on a catalyst supporting member 3. The raw reactant materials are flowed in a down-flow through the reactor, and the resultant reaction solution is then fed to the next step through a line 93 and a valve 82. Upon conducting the reverse washing procedure, the valves 81 and 82 are closed and the valves 83 and 84 are opened, whereby the raw phenol material solely is fed in an up-flow to the reactor 1 through lines 91 and 94 using the pump 7. The raw phenol material fed in an up-flow serves for washing the catalyst layer 4 and then is discharged outside through a line 95 and the valve 84. Upon the reverse washing, the catalyst layer is fluidized, so that the channeling formed in the catalyst layer upon the reaction is eliminated, and the reaction system is returned to the initial condition where the catalyst is uniformly filled in the reactor. The flow rate of the reaction solution is usually controlled to not less than a minimum fluidization velocity and not more than 12 0% of the minimum fluidization velocity. The reverse washing of the catalyst layer is preferably continued until the amount of the liquid flowed through the catalyst layer is not less than 0.5 times the amount of the catalyst. In this case, it is preferable that the fluidization velocity is selected from such a velocity that the reverse washed catalyst is not flowed out from the top of reactor to the outside of reactor. The minimum fluidization velocity may be determined by the method of calculating the velocity from specific gravity values of the liquid and the ion exchange resin, particle size and weight of the ion exchange resin, etc., or by the method of actually conducting experiments. After the reverse washing, the valves are change-over, thereby starting feed of the raw reactant materials and restarting the reaction thereof. In the process for producing bisphenol A according to the present invention, respective steps to be conducted subsequent to the above reaction step are not particularly limited, and may include, for example, conventionally known steps. Examples of the steps to be conducted subsequent to the reaction step may include a low-boiling component separation step of separating a reaction mixture obtained in the reaction step into a bisphenol A-containing component and a low-boiling component containing unreacted acetone, a crystallization step of crystallizing bisphenol A in the form of an adduct with phenol thereof from the bisphenol A-containing component to obtain a slurry thereof, a recovery step of separating the slurry obtained in the above crystallization step into crystals of bisphenol A/phenol adduct and a mother liquor to recover bisphenol A/phenol adduct, an impurity treating step of subjecting the thus separated mother liquor to alkali heat treatment and then to distillation to separate the mother liquor into a light weight component and a heavy weight component, and subjecting the thus separated light weight component to re-bonding reaction treatment, and an acetone recycling step of separating and recovering the unreacted acetone from the low-boiling component obtained in the low-boiling component separation step, and recycling the recovered unreacted acetone to the reaction step. EXAMPLES The present invention is described in more detail by the following examples. However, these examples are only illustrative and not intended to limit the scope of the present invention. Example 1: In Example 1, there was used the vertical type fixed bed reactor shown in Fig. 1. The reactor 1 having a radius of 2.8 m on a bottom thereof was filled with a sulfonic acid type cation exchange resin catalyst in which 15% of a sulfonic acid group thereof was modified with 2-(4- pyridyl)ethane thiol, so as to form a catalyst layer having a height 1 of 3.25 m (amount of the catalyst filled: 80 m3). In the catalyst layer, two thermocouple thermometers 5 were disposed at respective two positions both located at a distance r of 250 cm from an outer periphery of the reactor in a horizontal direction of the catalyst layer, and which were also located in a height direction of the catalyst layer, 15 cm from the lowest face of the catalyst layer (5% of a height of the catalyst layer from the lowest face thereof; measuring point 1 represented by reference numeral 52 in Fig. 1) and 47 cm from the lowest face of the catalyst layer (14% of a height of the catalyst layer from the lowest face thereof; measuring point 2 represented by reference numeral 53 in Fig. 1), respectively, as shown in Fig. 1. Further, an additional thermocouple thermometer 6 was disposed near an outlet of the reactor (measuring point 0 represented by reference numeral 51). As shown in Fig. 1, in the vertical type fixed bed reactor 1, a flow direction of the reaction solution therethrough was reversible by changing-over valves 81 to 84, and a minimum fluidization feed rate was 13.5 t/h. A mixed raw material containing a raw phenol material composed of 87% by weight of phenol and 13% by weight of other compounds (including bisphenol A and isomers thereof) and a raw acetone material having an acetone purity of 99.7% which were supplied at rates of 55 t/hr and 1.7 t/hr, respectively, was fed at 55°C from an upper portion of the reactor in a down-flow, and a continuous reaction therebetween was initiated under heat insulating conditions. It was confirmed that after the elapse of 10 hr from initiation of the reaction (time at which the reaction was stabilized), the conversion of acetone was 99.5%. At that time, the temperatures at the measuring points 1 and 2 both were 72.0°C, and the temperature at the outlet of the reactor (measuring point 0) was 72.0°C, i.e., the temperatures at these measuring points were identical to each other. After the elapse of 12 months from initiation of operation of the reactor, the temperatures at the measuring points 1 and 2 both were 72.9°C, and the temperature at the outlet of the reactor (measuring point 0) was 69.9°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 3.0°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 3.0°C. At that time, the conversion of acetone was 87.5%. Then, the valves 81 and 82 were closed and the valves 83 and 84 were opened, and the raw phenol material solely was fed in an up-flow at a temperature of 63.0°C and a flow rate of 15 t/hr for 3 hr to the reactor 1 through the lines 91 and 94 using the pump 7, thereby fluidizing the catalyst layer. Thereafter, feed of the raw reactant materials was restarted to initiate the reaction in a down-flow manner. After the elapse of 10 hr from initiation of the reaction, the temperatures at the measuring points 1 and 2 and at the outlet of the reactor (measuring point 0) all were 71.1°C, i.e., were identical to each other. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 0.0°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 0.0°C. At that time, the conversion of acetone was 94.5%. Thereafter, the operation of the reactor was continued, and after the elapse of 24 months from the first initiation of the reaction, the conversion of acetone was 82.0%. Comparative Example 1: The same procedure as defined in Example 1 was conducted except that after the elapse of 12 months from initiation of the operation, the reactor was further continuously operated without stopping the reaction and conducting the fluidization procedure. After the elapse of 24 months from the first initiation of the reaction, the temperatures at the measuring points 1 and 2 both were 71.9°C, and the temperature at the outlet of the reactor (measuring point 0) was 65.9°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 6.0°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 6.0°C. At that time, the conversion of acetone was 64.0%. Then, in the same manner as in Example 1, after the feed of the raw reactant materials was stopped and the flow direction of the solution was reversed, the raw phenol material solely was fed in an up-flow at a flow rate of 15 t/hr for 3 hr to the reactor, thereby fluidizing the catalyst layer at a reaction temperature of 69.0°C. Thereafter, the feed of the raw reactant materials was restarted to initiate the reaction in a down-flow manner. After the elapse of 10 hr from initiation of the reaction, the temperatures at the measuring points 1 and 2 both were 68.3°C and the temperature at the outlet of the reactor (measuring point 0) was 67.4°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 0.9°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 0.9°C. At that time, the conversion of acetone was 72.5%. Example 2: In Example 2, there was used a reactor having the same basic structure as that of the vertical type fixed bed reactor shown in Fig. 1. The reactor 1 having a radius of 3.3 m on a bottom thereof was filled with a sulfonic acid type cation exchange resin catalyst in which 15% of a sulfonic acid group was modified with 2-(4-pyridyl)ethane thiol, so as to form a catalyst layer having a height 1 of 3.2 m (amount of the catalyst filled: 110 m3). In the catalyst layer, two thermocouple thermometers 5 were disposed at respective two positions both located at a distance r of 300 cm from an outer periphery of the reactor in a horizontal direction of the catalyst layer which were also located in a height direction of the catalyst layer, 15 cm from the lowest face of the catalyst layer (5% of a height of the catalyst layer from the lowest face thereof; measuring point 1 represented by reference numeral 52 in Fig. 1) and 47 cm from the lowest face of the catalyst layer (14% of a height of the catalyst layer from the lowest face thereof; measuring point 2 represented by reference numeral 53 in Fig. 1), respectively. In the vertical type fixed bed reactor 1, a flow direction of the reaction solution therethrough was reversible by changing-over valves 81 to 84, and a minimum fluidization feed rate was 18.8 t/h. A mixed raw material containing the same raw phenol material and the same raw acetone material as used in Example 1 which were supplied at feed rates of 100 t/hr and 3.5 t/hr, respectively, was fed at 60.0°C from an upper portion of the reactor in a down-flow, and a continuous reaction therebetween was initiated under heat insulating conditions. It was confirmed that after the elapse of 10 hr from initiation of the reaction (time at which the reaction was stabilized), the conversion of acetone was 98.0%. At that time, the temperatures at the measuring points 1 and 2 and the temperature at the outlet of the reactor (measuring point 0) all were 78.7°C, i.e., the temperatures at these measuring points were identical to each other. After the elapse of 9 months from initiation of operation of the reactor, the temperatures at the measuring points 1 and 2 both were 74.6°C, and the temperature at the outlet of the reactor (measuring point 0) was 76.6°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 2.0°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 2.0°C. At that time, the conversion of acetone was 87.0%. Then, the valves 81 and 82 were closed and the valves 83 and 84 were opened, and the raw phenol material solely was fed in an up-flow at a temperature of 67.0°C and a flow rate of 20 t/hr for 3 hr to the reactor 1 through the lines 91 and 94 using the pump 7, thereby fluidizing the catalyst layer. Thereafter, feed of the raw reactant materials was restarted to initiate the reaction in a down-flow manner. After the elapse of 10 hr from initiation of the reaction, the temperatures at the measuring points 1 and 2 and at the outlet of the reactor (measuring point 0) all were 78.2°C, i.e., were identical to each other. At that time, the conversion of acetone was 95.5%. Thereafter, the operation of the reactor was continued, and after the elapse of 18 months from the first initiation of the reaction, the conversion of acetone was 81.5%. Comparative Example 2: The same procedure as defined in Example 2 was conducted except that after the elapse of 9 months from initiation of the operation, the reactor was continuously operated without stopping the reaction and conducting the fluidization procedure. After the elapse of 18 months from the first initiation of the reaction, the temperatures at the measuring points 1 and 2 both were 66.8°C, and the temperature at the outlet of the reactor (measuring point 0) was 72.4°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 5.6°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 5.6°C. At that time, the conversion of acetone was 61.0%. Then, in the same manner as defined in Example 1, the valves 81 and 82 were closed and the valves 83 and 84 were opened, and the raw phenol material solely was fed in an up-flow at a temperature of 65.0°C and a flow rate of 20 t/hr for 3 hr to the reactor 1 through the lines 91 and 94 using the pump 7, thereby fluidizing the catalyst layer. Thereafter, feed of the raw reactant materials was restarted to initiate the reaction in a down-flow manner. After the elapse of 10 hr from initiation of the reaction, the temperatures at the measuring points 1 and 2 both were 72.7°C, and the temperature at the outlet of the reactor (measuring point 0) was 73.5°C. That is, an absolute value of the temperature difference between the measuring points 1 and 0 was 0.8°C, whereas an absolute value of the temperature difference between the measuring points 2 and 0 was 0.8°C. At that time, the conversion of acetone was 70.5%. The timing of fluidization of catalyst layer, AT, conversion of acetone and operation time in the above Examples and Comparative Examples are collectively shown in Table 1. Table 1 (Table Removed) Although the present invention is described above with respect to embodiments which are considered to be most practical and preferable at the present time, the present invention is not limited to these embodiments, and various changes and modifications will be appropriately made within the scope of claims and a whole of a specification of this application unless departing from the subject matter and concept of the present invention, and it should be construed that the changes and modifications are involved within a technical range of the present invention. The present invention is based on Japanese Patent Application No. 2005-335795 filed on November 21, 2 005 and the whole content thereof can be incorporated by reference. WHAT IS CLAIMED IS; 1. A process for producing bisphenol A comprising a reaction step of flowing a raw phenol material and a raw acetone material through a vertical type fixed bed reactor filled with an ion exchange resin catalyst to obtain a bisphenol A-containing reaction solution, in which when an absolute value of a temperature difference (AT) between the reaction solution located at any position of a portion of an ion exchange resin catalyst layer formed in the reactor which portion extends from an outlet of the ion exchange resin catalyst layer up to 2 0% of a height of the catalyst layer, and the reaction solution located in an outlet of the vertical type fixed bed reactor, is 1.0 to 5.0°C, at least a part of the ion exchange resin catalyst is fluidized. 2. A process according to claim 1, wherein the ion exchange resin catalyst is fluidized by feeding a liquid in an up-flow through the vertical type fixed bed reactor. 3. A vertical type fixed bed reactor filled with an ion exchange resin catalyst, which has such an ability that a temperature of a reaction solution is measurable at least two positions of a portion of an ion exchange resin catalyst layer formed therein which portion extends from an outlet of the ion exchange resin catalyst layer up to 2 0% of a height of the catalyst layer. 4. A process according to claim 1 or 2, which is substantially as hereinbefore described with reference to any one of the foregoing examples and the accompanying drawing. 5. A vertical type fixed bed reactor according to claim 3, which is substantially as hereinbefore described with reference to any one of the foregoing examples and the accompanying drawing. 6. Bisphenol a produced according to the process of claim 1 or 2.

Documents:

4257-delnp-2008-abstract.pdf

4257-delnp-2008-Claims-(07-01-2014).pdf

4257-delnp-2008-claims.pdf

4257-delnp-2008-Correspondence Others-(02-05-2014).pdf

4257-delnp-2008-Correspondence Others-(07-01-2014).pdf

4257-delnp-2008-Correspondence Others-(10-10-2014).pdf

4257-delnp-2008-Correspondence Others-(19-11-2014).pdf

4257-delnp-2008-Correspondence Others-(22-10-2014).pdf

4257-delnp-2008-Correspondence-Others (09-11-2009).pdf

4257-delnp-2008-correspondence-others.pdf

4257-delnp-2008-description (complete).pdf

4257-delnp-2008-drawings.pdf

4257-delnp-2008-English-Translation-(19-11-2014).pdf

4257-delnp-2008-form-1.pdf

4257-delnp-2008-Form-18 (09-11-2009).pdf

4257-delnp-2008-Form-2-(07-01-2014).pdf

4257-delnp-2008-form-2.pdf

4257-delnp-2008-Form-3-(07-01-2014).pdf

4257-delnp-2008-form-3.pdf

4257-delnp-2008-form-5.pdf

4257-delnp-2008-GPA-(07-01-2014).pdf

4257-delnp-2008-GPA-(22-10-2014).pdf

4257-delnp-2008-pct-210.pdf

4257-delnp-2008-pct-301.pdf

4257-delnp-2008-pct-304.pdf

4257-delnp-2008-pct-308.pdf

4257-delnp-2008-Petition-137-(07-01-2014).pdf