Method for improving adamantane yield

Abstract

The invention relates to a method for improving the yield of adamantane, which comprises the following steps: carrying out rapid high-temperature reaction on mixed oil phase liquid generated after adamantane is separated in adamantane production in the presence of anhydrous aluminum trichloride and hydrogen chloride gas by adopting a special tubular reactor, so that a side reaction isomerization product in the mixed oil phase liquid is partially converted into adamantane; then separating out adamantane crystals through low-temperature cooling, and separating the crystals; the catalyst anhydrous aluminum trichloride particles and the hydrogen chloride gas exist in a reaction system at the same time, and are indispensable; the reaction temperature is 110 DEG C to 120 DEG C; the reaction time is 5-8 minutes; the method further improves the yield of the target product adamantane by 4-7%.

Description

Technical Field

[0001] The present invention relates to a method for reducing side reaction products and improving the yield of target product adamantane in the production process of synthesizing adamantane by isomerization reaction using tetrahydrodicyclopentadiene as a starting material Background Art

[0002] Adamantane is a cyclic tetrahedral alkane containing 10 carbon atoms and 16 hydrogen atoms. Its basic structure is chair-shaped cyclohexane. It is a highly symmetrical and very stable compound that can further react to produce a variety of derivative compounds. It has a wide range of applications in medicine, functional materials, electronic chemicals and other fields. At present, the large-scale production of adamantane products is mainly synthesized by isomerization reaction in the presence of anhydrous aluminum chloride using tetrahydrodicyclopentadiene as the starting material. In the traditional synthesis process, only 30% to 50% of the isomerization reaction of tetrahydrodicyclopentadiene becomes the target product adamantane, and the remaining starting materials generate difficult-to-treat polymerization tar due to polymerization side reactions, which brings about the environmental problem of difficult to handle production waste. After we adopt the improved "two-step one-cycle" method (CN200810045391) production process, the conversion yield of the target product adamantane is significantly improved, especially no polymerization tar is produced in the production process, and the starting raw material tetrahydrodicyclopentadiene is converted into the target product adamantane, and the rest is a mixed oil phase liquid of side reaction products and unreacted starting raw materials. The mixed oil phase liquid remaining after the reaction can be directly used as an extraction solvent for adamantane crystallization, or recycled as a fuel oil raw material and other uses.

[0003] In the practice of producing adamantane by the "two-step one-cycle" method, we observed that although there are several side reaction products produced in the production process, one of them always occupies the majority. The amount of this side reaction product usually accounts for 55% to 70% of the residual mixed oil phase liquid after the reaction, which is converted to 8% to 15% of the total conversion amount of the starting raw materials. On the component detection chromatogram, the peak position of the side reaction product is between the peak positions of the starting raw material tetrahydrodicyclopentadiene and the target product adamantane and is closer to the adamantane peak. Through the detection and analysis of the molecular structure of the side reaction product, the type and number of atoms in its molecule are the same as those of adamantane, but the ring structure is different. It is judged that the side reaction product is another isomerization product of tetrahydrodicyclopentadiene that undergoes disproportionation during the isomerization process to adamantane (hereinafter referred to as X isomerization byproduct).

[0004] Obviously, if the generation of X isomerization by-product is reduced during the isomerization reaction of adamantane, the yield of the target product adamantane can be increased accordingly. However, through multiple optimization and adjustment of the process parameters of the "two-step one-cycle" adamantane synthesis process, we observed that this X isomerization by-product is always difficult to reduce by controlling the isomerization reaction process conditions. In research practice, we found that when anhydrous aluminum chloride and hydrogen chloride are present at the same time, the X isomerization by-product will further isomerize and convert into adamantane at a high temperature higher than the usual reaction temperature of adamantane production. However, at high temperatures, the mixed oil phase liquid will also undergo polymerization side reactions to generate more colloids. Inspired by the above phenomenon, we considered changing our thinking and adopting a solution approach of subjecting the by-products of adamantane production to additional reaction treatment. Summary of the invention

[0005] The object of the present invention is to provide a method for reducing X isomerization by-products and improving the yield of target product adamantane in the production of adamantane synthesized by isomerization reaction using tetrahydrodicyclopentadiene as a starting material.

[0006] The object of the present invention is achieved in that:

[0007] According to the "two-step one-cycle method" synthesis process (CN200810045391), the scaled production of adamantane products is carried out by isomerization reaction in the presence of anhydrous aluminum chloride using tetrahydrodicyclopentadiene as the starting material. After the synthesis reaction operation is completed, the reaction system is composed of three phases of materials: target product adamantane crystals (solid phase), mixed oil phase liquid (liquid phase) in which saturated adamantane, side reaction impurities and unreacted starting materials are dissolved, and waste catalyst bottom material (liquid phase). Among them, the main component in the mixed oil phase liquid is the X isomerization byproduct. The present invention performs a second isomerization reaction on the X isomerization byproduct to convert it into adamantane.

[0008] The present invention adopts the following solution to reduce the X isomerization byproduct and correspondingly increase the yield of the target product adamantane:

[0009] 1. After the isomerization reaction of adamantane production is completed and the adamantane crystals and the mixed oil phase liquid are separated from the waste catalyst bottom material, the mixed oil phase liquid is further cooled to allow the adamantane dissolved therein to crystallize and separate as much as possible.

[0010] The cooling temperature of the mixed oil phase liquid is ≤-5°C. Under this low temperature condition, most of the adamantane dissolved in the mixed oil phase liquid is crystallized and precipitated. Continuing to lower the temperature has little effect on reducing the solubility of adamantane.

[0011] In the mixed oil phase liquid after low temperature separation and crystallization, the content of adamantane accounts for 2% to 3%, the content of unreacted starting raw material tetrahydrodicyclopentadiene accounts for 3% to 5%, the content of X isomerization by-product accounts for 55% to 70%, and the rest is other side reaction impurities.

[0012] 2. Using the mixed oil phase liquid whose main component is the X isomerization by-product from which the adamantane crystals have been separated as a raw material, a rapid high-temperature reaction is carried out in the presence of anhydrous aluminum chloride and hydrogen chloride, so that the X isomerization by-product in the mixed oil phase liquid is further isomerized into adamantane, while also preventing excessive polymerization side reactions from occurring due to excessive high-temperature time.

[0013] The mixed oil phase liquid after the reaction is cooled to allow the newly converted adamantane to crystallize and be separated and recovered.

[0014] The reaction heating temperature of the mixed oil phase liquid is 100°C to 130°C, preferably 110°C to 120°C, and the heating reaction time is 3 to 10 minutes, preferably 5 to 8 minutes. The cooling crystallization temperature of the oil phase liquid after the reaction is ≤-5°C.

[0015] In order to meet the conditions of rapid high temperature, short time reaction and the coexistence of anhydrous aluminum chloride and hydrogen chloride in the reaction system, we designed and used a special reactor in actual operation:

[0016] The main body of the special reactor is made of acid-resistant material and is a long tube type. There is a jacket layer outside the reaction tube, and the heating medium is passed through the jacket layer. The reaction tube is a reaction space, the tube diameter is 100mm~150mm, the tube length is 2m~3m, the top of the reaction tube is provided with a liquid inlet and an emptying port, and the bottom of the reaction tube is provided with a gas feed port and a liquid outlet. A filter is provided at the lower part of the reaction tube, and a catalyst filler is filled on the filter in the reaction tube. The catalyst filler is composed of small ceramic rings and anhydrous aluminum chloride particles, wherein the ceramic rings and aluminum chloride particles each occupy about 1 / 2 of the space in the reaction tube. The filling method can be to mix the ceramic rings and aluminum chloride particles and then load them, or the ceramic rings and aluminum chloride particles can be loaded alternately in thin layers.

[0017] The reaction tube is placed vertically, and a rapid liquid preheater is provided before the top, and a cooling tube is provided after the bottom of the reaction tube. During operation, hydrogen chloride gas is introduced from the bottom of the reaction tube, and a micro-pressure (0.01MPa-0.05MPa) hydrogen chloride atmosphere is formed in the reaction tube. The mixed oil phase liquid is quickly heated by the preheater and pumped into the top of the reaction tube, flows through the reaction tube and contacts with the catalyst filling material to react, then flows out from the bottom of the reaction tube and is cooled by the cooling tube and collected.

[0018] In actual reaction operation, the liquid temperature of the mixed oil phase liquid is controlled at 110° C. to 120° C. when passing through the preheater and the reaction tube, and the residence time of the mixed oil phase liquid in the reactor is controlled at 5 to 8 minutes.

[0019] Through many experimental investigations, it is known that the further isomerization of the isomerized byproduct X into adamantane can only be carried out effectively in the presence of anhydrous aluminum chloride and sufficient hydrogen chloride. Both are indispensable.

[0020] The experiment also found that further isomerization reaction must occur at a higher temperature. When the temperature is below about 95°C, the further isomerization reaction rate is very slow. When the temperature is higher, the further isomerization reaction rate is faster, but at the same time, the rate of generating colloids by polymerization side reactions also becomes faster, even exceeding the isomerization reaction. As the colloids of polymerization side reactions increase, the yield of isomerization reaction products (adamantane) will decrease accordingly. Through repeated experimental investigations, it was determined that controlling the reaction temperature in the range of 100°C to 130°C can achieve better final isomerization reaction effects. In actual operation, it is better to control the reaction temperature in the range of 110°C to 120°C. In this temperature range, both a better isomerization reaction rate can be obtained and the polymerization side reaction rate can be partially limited.

[0021] The experiment also found that as the reaction time increases, the amount of side reaction polymer colloids generated increases rapidly. Through repeated experimental investigations, it was determined that the reaction time should be controlled within 3 to 10 minutes. In actual operation, it is usually best to control it within 5 to 8 minutes. During this reaction time period, a relatively good yield of the isomerization reactant (adamantane) can be obtained.

[0022] According to the method of the present application, the mixed oil phase liquid produced in the production of adamantane is used as a raw material for further isomerization reaction, and 50% to 60% of the X isomerization by-product in the mixed oil phase liquid can be converted into adamantane, thereby increasing the yield of tetrahydrodicyclopentadiene, the starting raw material for the production of adamantane, to adamantane by 4% to 7% on the original basis.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] By adding the technology of the present invention to the existing process of synthesizing adamantane using tetrahydrodicyclopentadiene as the starting material according to the "two-step one-cycle method", the yield of the target product adamantane can be further increased by 4% to 7%. DETAILED DESCRIPTION

[0025] The object of the present invention is achieved in that:

[0026] 1. After the isomerization reaction of adamantane production is completed and the adamantane crystals and the mixed oil phase liquid are separated from the waste catalyst bottom material, the mixed oil phase liquid is first placed at ≤-5°C for further cooling to allow the adamantane dissolved therein to crystallize and separate as much as possible.

[0027] In the mixed oil phase liquid after low temperature separation and crystallization, the content of adamantane accounts for 2% to 3%, the content of unreacted starting raw material tetrahydrodicyclopentadiene accounts for 3% to 5%, the content of X isomerization by-product accounts for 55% to 70%, and the rest is other side reaction impurities.

[0028] 2. The mixed oil phase liquid whose main component is the X isomerization by-product separated from the adamantane crystals is used as a raw material, and a rapid high-temperature reaction is carried out in the presence of anhydrous aluminum chloride and hydrogen chloride, so that the X isomerization by-product in the mixed oil phase liquid is further isomerized into adamantane, and the high-temperature reaction time is also controlled to prevent the mixed oil phase liquid from being at high temperature for too long and causing excessive polymerization side reactions.

[0029] The mixed oil phase liquid after the reaction is cooled at ≤-5°C to allow the newly converted adamantane to crystallize and be separated and recovered.

[0030] The reaction heating temperature of the mixed oil phase liquid is 100°C to 130°C, preferably 110°C to 120°C, and the heating reaction time is 3 to 10 minutes, preferably 5 to 8 minutes.

[0031] 3. In order to meet the conditions of rapidly raising the temperature, controlling the reaction in a short time and maintaining the simultaneous presence of anhydrous aluminum chloride and hydrogen chloride in the reaction system, a special reactor was designed and used in the actual operation:

[0032] The main body of the special reactor is made of acid-resistant material and is a long tube type. There is a jacket layer outside the reaction tube, and a heating medium is passed through the jacket layer. The reaction tube is a reaction space. The tube diameter is 100mm-150mm, and the tube length is 2m-3m. The top of the reaction tube is provided with a liquid inlet and an emptying port, and the bottom of the reaction tube is provided with a gas feed port and a liquid outlet. A filter is provided at the lower part of the reaction tube, and a catalyst filler is filled on the filter in the reaction tube. The catalyst filler is composed of small ceramic rings and anhydrous aluminum chloride particles, wherein the ceramic rings and the aluminum chloride particles each occupy about 1 / 2 of the space in the reaction tube; the filling method can be to mix the ceramic rings and the aluminum chloride particles and then load them, or to alternately load the ceramic rings and the aluminum chloride particles in thin layers;

[0033] The reaction tube is placed vertically, and a rapid liquid preheater is arranged before the top, and a cooling tube is arranged after the bottom of the reaction tube. During operation, hydrogen chloride gas is introduced from the bottom of the reaction tube, and a hydrogen chloride atmosphere with a micro-pressure of 0.01MPa to 0.05MPa is formed in the reaction tube. The mixed oil phase liquid is quickly heated by the heater and then pumped into the top of the reaction tube, flows through the reaction tube and contacts with the catalyst filling material to react, and then flows out from the bottom of the reaction tube and is collected after being cooled by the cooling tube.

[0034] Example

[0035] The mixed oil phase liquid produced in the large-scale production process of adamantane was taken and cooled in a -5°C to -10°C refrigerator overnight. The adamantane crystals were separated by filtration while cold, and the residual filtrate content was detected to be: 3.9% tetrahydrodicyclopentadiene, 2.7% adamantane, 63.2% X-isomerization by-products, and the rest were other side reaction impurities.

[0036] Take 6000g of the mixed oil phase liquid filtrate, pump it into a pre-heated special reactor, keep the hydrogen chloride gas pressure in the reaction tube within the range of 0.01MPa to 0.05Mpa, control the temperature of the mixed oil phase liquid material in the reaction tube to be 115℃±2℃, let the mixed oil phase liquid flow out from the bottom of the reaction tube after 5 to 8 minutes from the top of the reaction tube, and flow through the cooling tube (cooled with normal temperature cooling water outside the tube) and then enter the collection bottle. Put the collection bottle containing the reacted mixed oil phase liquid in a refrigerator at -5℃ to -10℃ to cool overnight, and filter and separate the precipitated adamantane crystals while it is cold.

[0037] 5713 g of the mixed oil phase liquid (including mixed crystals) after the reaction was collected (there was still accumulated material in the reaction tube). After cooling and separating the crystals, 1702 g of crude crystals and 3984 g of filtrate were obtained (there was loss during the suction filtration operation).

[0038] The purity of adamantane in the crude crystals was 95.2%, which was converted into 1621 g of pure adamantane crystals. Most of the adamantane collected was generated by the conversion of X isomerization byproducts, and a small part was generated by the isomerization of tetrahydrodicyclopentadiene.

[0039] The components of the filtrate sampled and tested were: 0.4% tetrahydrodicyclopentadiene, 2.3% adamantane, 27.7% X-isomerization by-product, and the rest were other side reaction impurities.

Claims

1. A method for improving the yield of adamantane, wherein the large-scale production of adamantane products is synthesized by isomerization reaction in the presence of anhydrous aluminum chloride using tetrahydrodicyclopentadiene as a starting material, wherein the starting material tetrahydrodicyclopentadiene is converted into the target product adamantane, and the rest is a mixed oil phase liquid of side reaction products and unreacted starting materials, wherein: The following steps are involved: 1) After the isomerization reaction is completed, the adamantane crystals and the mixed oil phase liquid are separated from the waste catalyst bottom material, and the mixed oil phase liquid is further cooled to allow the adamantane dissolved therein to crystallize and separate as much as possible; The cooling temperature of the mixed oil phase liquid is ≤-5°C. Under this low temperature condition, most of the adamantane dissolved in the mixed oil phase liquid is crystallized and precipitated. In the mixed oil phase liquid after separation and crystallization, the adamantane content accounts for 2% to 3%, the unreacted starting raw material tetrahydrodicyclopentadiene content accounts for 3% to 5%, the X isomerization by-product accounts for 55% to 70%, and the rest is other side reaction impurities. 2) Using the mixed oil phase liquid whose main component is the X isomerization byproduct from which the adamantane crystals have been separated as a raw material, a rapid high-temperature reaction is carried out in the presence of anhydrous aluminum chloride and hydrogen chloride, so that the X isomerization byproduct in the mixed oil phase liquid is further isomerized into adamantane, while also preventing excessive polymerization side reactions from occurring due to excessive high-temperature time; The mixed oil phase liquid after the reaction is cooled to allow the newly converted adamantane to crystallize and be separated and recovered; The reaction heating temperature of the mixed oil phase liquid is 100°C to 130°C, preferably 110°C to 120°C, the heating reaction time is 3 to 10 minutes, preferably 5 to 8 minutes; the cooling crystallization temperature of the oil phase liquid after the reaction is ≤-5°C.

2. A method for improving the yield of adamantane according to claim 1, characterized in that: In order to meet the conditions of rapid high temperature, short time reaction and the coexistence of anhydrous aluminum chloride and hydrogen chloride in the reaction system, a special reactor was designed and used in actual operation: the main body of the special reactor is made of acid-resistant material, and is a long tube type. There is a jacket layer outside the reaction tube, and the heating medium is passed through the jacket layer. The reaction tube is a reaction space, the tube diameter is 100mm-150mm, and the tube length is 2m-3m. The top of the reaction tube is provided with a liquid inlet and an emptying port, the bottom of the reaction tube is provided with a gas feed port and a liquid outlet, and a filter is provided at the lower part of the reaction tube. The filter in the reaction tube is filled with catalyst filling material, and the catalyst filling material is composed of small ceramic rings and anhydrous aluminum chloride particles, wherein the ceramic rings and the aluminum chloride particles each occupy about 1 / 2 of the space in the reaction tube; the filling method can be to mix the ceramic rings and the aluminum chloride particles and then load them, or to alternately load the ceramic rings and the aluminum chloride particles in thin layers; The reaction tube is placed vertically, and a rapid liquid preheater is arranged before the top, and a cooling tube is arranged after the bottom of the reaction tube. During operation, hydrogen chloride gas is introduced from the bottom of the reaction tube, and a hydrogen chloride atmosphere with a micro-pressure of 0.01MPa to 0.05MPa is formed in the reaction tube. The mixed oil phase liquid is quickly heated by the heater and then pumped into the top of the reaction tube, flows through the reaction tube and contacts with the catalyst filling material to react, and then flows out from the bottom of the reaction tube and is cooled by the cooling tube before being collected. In actual reaction operation, the liquid temperature of the mixed oil phase liquid is controlled at 110° C. to 120° C. when passing through the preheater and the reaction tube, and the residence time of the mixed oil phase liquid in the reactor is controlled at 5 to 8 minutes.

3. A method for improving the yield of adamantane according to claim 1, characterized in that: By using the mixed oil phase liquid produced in the production of adamantane as a raw material for further isomerization reaction, 50% to 60% of the X isomerization by-product in the mixed oil phase liquid can be converted into adamantane, thereby increasing the yield of converting tetrahydrodicyclopentadiene, the starting raw material for the production of adamantane, into adamantane by 4% to 7% on the original basis.