A cyclopentadiene selective hydrogenation by the production method of the cyclopentene

Technical Field

The invention relates to a selective hydrogenation production of the cyclopentene derivative of the method.

Background Art

Cyclopentene is an important fine chemical raw materials, can be used for preparing cyclopentanol, cyclopentanone, glutaraldehyde, bromo cyclopentane, chlorocyclopentane such high value added product, but also is poly cyclic olefin polymer of the main raw material.

At present, cyclopentene mainly through the cyclopentadiene selective hydrogenation is prepared by the method. Cyclopentadiene is mainly from the ethylene cracking by-product carbon five fraction. In the room temperature due to, cyclopentadiene is easy to auto-polymerization reaction produce a relatively more stable dicyclopentadiene, therefore industrial cyclopentadiene usually to dimer form to store. When in use, only the double-cyclopentadiene conventional atmospheric distillation, collecting tower top temperature in the 40 - 44 °C fraction, can get cyclopentadiene.

Cyclopentadiene molecule contains two reactive double bond, in typical under hydrogenation conditions, first a double bond is to produce the cyclopentene, generation of the double bond in the molecule of the cyclopentene, will also be the occurrence of further hydrogenation reaction to produce the cyclopentane. The cyclopentadiene produces cyclopentene reaction activation energy compared to link pentene hydrogenation reaction activation energy generating cyclopentane slightly low, therefore only at a relatively low temperature reaction, can be more advantageously enables the reaction to stay at the stage of generating cyclopentene.

Cyclopentadiene hydrogenation according to the reactor pattern can be divided into kettle type intermittent hydrogenation process and fixed bed continuous hydrogenation process. For example CN1417179, CN1462734 and CN102728386, respectively discloses a tank reactor of the cyclopentadiene intermittent hydrogenation process. The intermittent hydrogenation process the catalyst powder or small particles, the presence of the catalyst and the problem of separation of the product is not easy, is not suitable for large-scale continuous production.

Cyclopentadiene fixed bed hydrogenation process according to the reaction conditions may be divided into a gas-phase hydrogenation process and liquid phase hydrogenation process. Literature (natural gas and chemical industry, 2012,37, 20) And documentation (Hebei University of technology journal, 2011,40, 40) Respectively reporting a cyclopentadiene gas-phase hydrogenation of cyclopentene of the method, the reaction temperature is usually higher than 100 °C, because the reaction temperature is relatively high, to the detriment of the control cyclopentene further hydrogenation reaction generating cyclopentane reaction, generation of the cyclopentane is bound to increase the follow-up to the load of the separation process. In addition, gas-phase hydrogenation process required by the relatively large volume of the reactor, the equipment investment costs are relatively high.

Cyclopentadiene fixed bed liquid phase hydrogenation is the preferred technical proposal of the field. For example, US3994986, CN1011877 and documentation (petrochemical technology and application, 2009, 27, 218), respectively discloses a supported palladium catalyst of cyclopentadiene fixed bed hydrogenation production of the cyclopentene method, because the noble metal Pd of the expensive price, the existing technical proposal the presence of a catalyst the deficiency of the high cost.

Content of the invention

The existing cyclopentadiene fixed bed liquid phase hydrogenation of the present technology, the invention provides a method using a non-noble metal catalyst of the cyclopentadiene selective hydrogenation by the production method of the cyclopentene.

The invention relates to a selective hydrogenation production by the cyclopentadiene cyclopentene method, comprises the following steps:

(1) Containing cyclopentadiene raw material mixed with a solvent after the hydrogenation reaction as the raw material, and then is mixed with hydrogen after is filled continuously through the selective hydrogenation catalyst fixed bed reactor; wherein the selective hydrogenation catalyst is composed of active component amorphous nickel phosphide, alumina carriers and a helps the medicinal preparation cerium, the catalyst in the XRD spectrum of Ni-free₂ P or Ni₁₂ P₅ The diffraction peak, in the final catalyst, the active component of nickel in the amorphous nickel phosphide the weight content of the metallic nickel meter, of the total weight of the catalyst 10 - 15%, phosphorus and nickel in a molar ratio of 2.0 - 2.4: 1, helps the medicinal preparation cerium and nickel in a molar ratio of 0.01 - 0.05: 1, and the rest is carrier;

(2) Step (1) hydrogenation product into the 1st after separating the hydrogen out of the rectification column, the bottom of the column separation of the impurity, the overhead of the rectification column and feeding is extracted as the 2nd;

(3) Step (2) into the top of the rectifying tower distillate 1st 2nd rectifying tower, the bottom of the column cyclopentene product, the light component is extracted as circulating solvent, returning to step (1) for recycling.

The method of the invention step (1) in, selective hydrogenation catalyst preparation method is as follows:

(1) Preparing an acidic nickel salt water solution, then adding dibasic phosphate, adjuvant-containing X salts and citric acid, the molar ratio of phosphorus to nickel/2.5 - 3.0, X/nickel molar ratio of 0.01 - 0.05: 1, citric acid/nickel molar ratio of 1.0 - 2.0: 1, to obtain solution A, to the obtained solution is added in the A metering of alumina or aluminum hydroxide, form the slurry B, then slowly evaporated moisture, forming adhesive C;

(2) Step (1) obtained in the continuous flow of adhesive C is placed under an inert gas atmosphere, the temperature to 250 - 350 °C lower, and the temperature processing 5 - 10 hours, so that the adhesive in the citric acid decomposition reaction, to obtain catalyst precursor D;

(3) Step (2) in the obtained catalyst precursor D molding, forming catalyst after drying, to obtain forming catalyst precursor E;

(4) In the step (3) is received in the shaped catalyst precursor E in hydrogen atmosphere to reduction, reduction temperature is 300 - 400 °C, reduction time is 1 - 10 h, to be catalyst after reduction, cooling to room temperature, to oxygen concentration is 0.5 - 1.0% at room temperature of the catalyst carried on the passivation 0.5 - 1 h, obtained hydrogenation catalyst selectivity.

The method of the invention step (1) in, the solvent by mass fraction is 10 - 80% of a ethyl ether and 20 - 90% of the ether composition. As the method of the invention further preferably, the step (1) in the solvent by the mass fraction is 20 - 80% of a ethyl ether and 20 - 80% of the ether composition.

The method of the invention step (1) in, the cyclopentadiene-containing raw materials from the dicyclopentadiene cracking or methyl cyclopentadiene dimer of cracking, wherein the cyclopentadiene or methyl cyclopentadiene mass fraction of 98% or more.

The method of the invention step (1) in, in the hydrogenation reaction of the raw materials, cyclopentadiene mass fraction of 1 - 25%, preferably 10 - 25%.

The method of the invention step (1) in, the reaction conditions: reactor inlet temperature is 20 - 60 °C, the reaction pressure is 0.5 - 1.1 mpa, quality airspeed for 1 - 4 h^-1 , Hydrogen with cyclopentadiene in a molar ratio of 1.1 - 2.0; preferably the reactor inlet temperature is 40 - 60 °C, the reaction pressure is 0.9 - 1.1 mpa, quality airspeed is 2 - 4 h^-1 , Hydrogen with cyclopentadiene in a molar ratio of 1.1 - 1.3.

The method of the invention step (2) in the sump temperature is 215 - 255 °C, tower-top temperature is 60 - 85 °C, top of the tower pressure is 0.50 - 0.65 mpa.

The method of the invention step (2) in, the theoretical plate number of the rectification column and 1st is 10 - 20 block. As a further preferred method of the invention, the 1st theoretical plate number of the rectification column for 15 block, 1st rectifying tower can be arranged in the tray, and can also be filled with the filler.

The method of the invention step (3) in, the sump temperature is 95 - 120 °C, tower-top temperature is 55 - 80 °C, top of the tower pressure is 0.45 - 0.70 mpa,

The method of the invention step (3) in, the 2nd theoretical plate number of the rectification column is 60 - 70 block. As the method of the invention further preferably, the 2nd theoretical plate number of the rectification column and is 65 block, 2nd rectifying tower can be arranged in the tray, and can also be filled with the filler.

Cyclopentadiene to produce the ring pentene and cyclopentene hydrogenation generating cyclopentane are strong exothermal reaction, a typical liquid-phase hydrogenation under the conditions, the reaction heat of the two are higher than the 100 kJ/mol, releasing the heat of the latter greater. It is believed that, if the reaction temperature is higher than 120 °C, cyclopentene hydrogenation generating cyclopentane will obviously accelerate the reaction speed, resulted in a decline in the cyclopentene selectivity, it on the one hand because of the cyclopentane and cyclopentene close boiling point products, will affect the cyclopentene product quality and increase the difficulty in separating the follow-up of the product. Therefore, removal of the heat of the reaction and control the reaction at a relatively low temperature, will be high selectively production and separation and purification of the cyclopentene key.

The key of this invention one of the active components is the introduction of the amorphous nickel phosphide, alumina carrier and helps the medicinal preparation cerium form a non-noble metal selective hydrogenation catalyst. With the existing technical scheme adopted in the Pd compared with the noble metal catalyst, catalyst of this invention has the advantages of low cost, the advantages of high selectivity of the cyclopentene.

In addition, another aspect of the invention one of the keys to the invention is characterized in that the solvent of the composition by a ethyl ether and ethyl ether. A diethyl ether in the invention adopted by the boiling point of the reaction under the pressure of the 79.0 - 87.9 °C. The present invention under the conditions adopted in the reaction, cyclopentadiene hydrogenating exothermic end connected to the ether gasification, dimethyl ether of the latent heat of vaporization to control the temperature of the catalyst bed. By adjusting the content of the solvent in a ether, the catalyst bed temperature can be stably controlled in the 80 - 90 °C, ensures this invention adopts the selective hydrogenation catalyst to give full play to its own excellent catalytic performance, the cyclopentane by-product selective control in 0.5% the following.

Because this invention adopts the solvent consists of a ethyl ether and ethyl ether composition, the two under the atmospheric pressure is lower than the boiling point of the cyclopentadiene raw materials and cyclopentene product, which makes the product of the separation process is greatly simplified. Compared with the prior art, the method of the invention saves the solvent separation step, the solvent and unreacted cyclopentadiene raw materials common to 2nd light component extracted of the rectification column, can be used as the circulation solvent of the present invention, on the other hand can also be the unreacted cyclopentadiene raw material back to the hydrogenation reactor to continue the reaction. After to be device reaches the steady state, solvent and a part of the unreacted cyclopentadiene raw materials in the device cycle, can improve the fresh raw materials in the conversion of the cyclopentadiene, and does not need to supplement the fresh solvent.

Description of drawings

Figure 1 schematic view for the procedure of this invention.

Figure 1 in, 1 - raw material storage tank, 2 - pump, 3 - hydrogenation reactor, 4 - gas-liquid separator, 5 - pump, 6 - 1st rectifying tower, 7 - 2nd rectifying tower.

Figure 1 in the 101 - 111 to logistics, wherein 101 - cyclopentadiene-containing raw materials, 102 - fresh solvent, 103 - hydrogenation reaction material, 104 - hydrogen, 105 - hydrogenation reaction effluent, 106 - circulating hydrogen, 107 - 1st for the rectification column, 108 - recombinant sub-impurity, 109 - 2nd the rectification column, 110 - cyclopentene product, 111 - circulating solvent.

Figure 2 is the XRD spectrum of this invention adopts the selective hydrogenation catalyst.

Mode of execution

The following combined with photos and embodiment of the invention for further description. The following is only the invention preferred specific embodiments, but the scope of protection of the present invention is not limited to this, any familiar with this technical field technical personnel can easily think of the change or replacement, should cover the protection range of this Patent.

As shown in Figure 1 containing cyclopentadiene raw material (101) with fresh solvent (102) and circulating solvent (111) in the raw material storage tank 1 and mixing, a hydrogenation reaction material (103); regulating the flow of material, so that the hydrogenation in the materials of the cyclopentadiene mass fraction of 10 - 25%, solvent in a ether mass fraction of 20 - 80%; hydrogenation reaction material (103) through with hydrogen (104) enters into the hydrogenation reactor 2, in under the action of the selective hydrogenation catalyst, the reactor inlet temperature is 40 - 60 °C, the reaction pressure is 0.9 - 1.1 mpa, quality airspeed is 2 - 4 h^-1 , Hydrogen with cyclopentadiene in a molar ratio of 1.1 - 1.3 of the conditions, the occurrence of the cyclopentadiene selective hydrogenation reaction; generating hydrogenation reaction effluent (105) in the gas-liquid separation tank 4 in the gas-liquid separation, separating the hydrogen out (106) can be recycled; separating the liquid phase hydrogenation product as the 1st rectifying tower 6 feed (107), the sump temperature is 215 - 255 °C, tower-top temperature is 60 - 85 °C, top of the tower pressure is 0.50 - 0.65 mpa under the condition of the operation, the bottom of the column separation of impurity (108); 2nd 1st rectifying tower overhead of the rectification column as a feed (109), the sump temperature is 95 - 120 °C, tower-top temperature is 55 - 80 °C, top of the tower pressure is 0.45 - 0.70 mpa under the condition of the operation, the bottom of the column cyclopentene product (110), an overhead light component as circulating solvent (111), back to the raw material storage tank 1 for recycling.

The following further description of the embodiment of the combined effect of the present invention.

Embodiment 1 - 4

Catalyst preparation step (1)

According to table 1 is shown the weight weighing six water nickel nitrate by adding 500 ml deionized water, then adding 0.05 mol/L nitric acid to adjust the pH value to 2 - 3, and then according to the table 1 shown in added weight dibasic phosphate, six water cerous nitrate, citric acid monohydrate, then stirring at room temperature 1 hour, respectively to obtain solution A1 - A4.

Table 1

To the solution are A1 - A4 is added in aluminum hydroxide 77 g, 72 g, 67 g and 78 g, disperse in solution, to respectively obtain the slurry B1 - B4, then the resulting slurry into the rotary evaporator in 85 °C under moisture of evaporation to dryness, then the 120 °C dried under 24 hours, to obtain the adhesive C1 - C4.

Catalyst preparation step (2)

The adhesive C1 - C4 is arranged in the tube-type heating furnace, in a continuous flow of N₂ In the atmosphere, for 250 - 300 °C lower processing 3 - 10 hours, so that the adhesive in the citric acid decomposition reaction, to reach the required processing time, the temperature is reduced to room temperature (25 °C) taken out, to respectively obtain the catalyst precursor D1 - D4. Processing conditions shown in table 2.

Table 2

Catalyst preparation step (3)

The catalyst precursor D1 - D4 with a proper amount of nitric acid, water, mixed kneading, extrusion molding. After extrusion, the resulting extrudate prior to drying them at room temperature 24 hours, then 120 °C drying 24 hours, respectively to obtain forming catalyst precursor E1 - E4.

Catalyst preparation step (4)

According to table 3 the conditions set forth in, the formed catalyst precursor E1 - E4 are respectively arranged in the tube-type heating furnace, in a continuous flow of H₂ In the atmosphere, in the 350 - 400 °C reduction under the 5 - 10 hours. After the needed reduction time, the temperature is reduced to room temperature (25 °C), then in order to oxygen volume concentration is 0.75% of O₂ /N₂ The passivation is mad rightly catalyst passivation 0.8 hours, to obtain the final step activating catalyst F1 - F4.

Table 3

The X-ray diffraction (XRD) to the step activating catalyst F1 - F4 to carry on the characterization, the results show that catalyst on nickel phosphide in an amorphous state. Figure 2 is the XRD spectrum of F1 - F4 of the catalyst.

The inductively coupled plasma (ICP) emission spectrum for determining the step activating catalyst composition. Loading Ni Ni metal weight to weight percent of the total catalyst, the content of P to P/Ni content respectively and Ce, Ce/Ni molar ratio. F1 catalyst: Ni content 10.12%, P/Ni=2.35, Ce/Ni=0.01; F2 catalyst: Ni content 12.51%, P/Ni=2.24, Ce/Ni=0.03; F3 catalyst: Ni content 14.96%, P/Ni=2.06, Ce/Ni=0.05; F4 catalyst: Ni content 10.23%, P/Ni=2.14, Ce/Ni=0.02.

Examples 5 - 9

Each embodiment of the invention for the purpose of cyclopentadiene-containing raw materials from the dicyclopentadiene cracking, wherein the cyclopentadiene mass fraction of 98%, the rest is dicyclopentadiene.

Each embodiment of the invention adopts the process flow as shown in Figure 1. Table 4 lists of each embodiment of the hydrogenation reaction of the raw material (103) composition.

Table 4

Table 5 lists the embodiments of the present invention the hydrogenation reactor operating conditions.

Table 5

In order to illustrate the effect of the method, the one-way conversion of cyclopentadiene, cyclopentene one-way selective cyclopentane and one-way selective presentation of the method of the invention has the beneficial role of cyclopentadiene of the selective hydrogenation.

Table 6 lists each embodiment of the invention cyclopentadiene selective hydrogenation of the one-way reaction results. The method of the invention by controlling the solvent in the mass fraction of methyl ethyl ether, methyl ethyl ether in the reaction of the invention under the conditions of the reaction of the absorbing cyclopentadiene hydrogenating the heat of gasification, the use of a ethyl ether of the latent heat of vaporization to control the catalyst bed temperature, so that the hydrogenation reaction is maintained at a relatively low temperature. As shown in table 6 as shown, the method of the invention can make the hydrogenation reactor outlet temperature control in the 80 - 90 °C, is conducive to this invention adopts the selective hydrogenation catalyst to give full play to its own excellent catalytic performance, will therefore be cyclopentadiene depth to produce the one-way selective control in the cyclopentane of 0.5% the following, obtain higher product selectivity of the cyclopentene.

Table 6

Table 7 lists each embodiment of the invention a hydrogenation product of the separation and refining process conditions, the process flow as shown in Figure 1. 1st theoretical plate number of the rectification column for 15 block, 2nd theoretical plate number of the rectification column and is 65 block. Each embodiment of the invention adopts the rectifying tower can be provided with a distillation column plate, can also be filled with the filler. Plate-type tower and filler tower and are well known to the technical personnel in the field of technical content. Embodiments of the present invention adopting a filling tower, the filler used for metal Powell ring packing.

Table 7

Table 8 lists the cyclopentene product (110) and circulating solvent (111) composition. The method of the invention after the throwing device reaches the steady state, does not need to add fresh solvent. Table 9 shown, another object of the invention is beneficial effect, unreacted circulating solvent returned to the hydrogenation reactor to continue to reaction, the total conversion of cyclopentadiene can be improved to 99% or more, cyclopentene to raise the total yield of products is 97% or more.

Table 8

Table 9