阅读说明：本技术 一种全氟烷基碘的制备方法 (Preparation method of perfluoroalkyl iodide ) 是由 张立亭 李坤 于 2021-01-27 设计创作，主要内容包括：本发明属于化工及医药中间体制备领域,具体涉及一种相对单组分全氟烷基碘的制备方法。具体过程为：将自制固定着床催化剂位于反应器4/5～7/8处,气相上翻搅拌翼位于反应器1/2～2/3处,抽真空、高纯氮气置换,再抽空,压入原料F(CF-2CF-2)-nI,加热,维持原料自身压力,开启气相上翻搅拌翼,通入四氟乙烯,保压反应,降温后把物料导入精馏系统,脱除原料,得到产物。本发明采用自制固定着床催化剂,四氟乙烯与原料接触反应时间短,减少产物与四氟乙烯的再次反应；充分利用原料与产物自身汽化分压,提高原料与四氟乙烯接触概率、降低产物与四氟乙烯接触概率,获得85～95%相对单组分全氟烷基碘化物。(The invention belongs to the field of chemical industry and pharmaceutical intermediate preparation, and particularly relates to a preparation method of a relative single-component perfluoroalkyl iodide. The specific process is as follows: the self-made fixed-bed catalyst is positioned at 4/5-7/8, the gas-phase upturning stirring wings are positioned at 1/2-2/3, the reactor is vacuumized, replaced by high-purity nitrogen, evacuated and pressed with a raw material F (CF) 2 CF 2 ) n Heating, maintaining the pressure of the raw materials, turning on a gas-phase upturning stirring wing, introducing tetrafluoroethylene, maintaining the pressure for reaction, cooling, introducing the materials into a rectification system, and removing the raw materials to obtain a product. The self-made fixed-bed catalyst is adopted, the contact reaction time of the tetrafluoroethylene and the raw materials is short, and the secondary reaction of the product and the tetrafluoroethylene is reduced; the vaporization partial pressure of the raw materials and the products is fully utilized, the contact probability of the raw materials and the tetrafluoroethylene is improved, the contact probability of the products and the tetrafluoroethylene is reduced, and 85-95% of relative single-component perfluoroalkyl iodide is obtained.)

1. A preparation method of perfluoroalkyl iodide is characterized by preparing a self-made fixed-bed catalyst, positioning the self-made fixed-bed catalyst at 4/5-7/8 of a stainless steel pressure-resistant reactor with gas-phase upturning stirring wings, positioning the gas-phase upturning stirring wings at 1/2-2/3 of the reactor, vacuumizing and replacing for 2 times by high-purity nitrogen, vacuumizing until the pressure in the reactor does not drop any more, and pressing in a raw material F (CF) into the reactor₂CF₂)_nHeating to a certain temperature, maintaining the pressure of the raw materials, starting a gas-phase upturning stirring wing, introducing tetrafluoroethylene, maintaining the pressure for reaction, stopping feeding when the tetrafluoroethylene is added into the raw materials in a certain proportion, cooling, introducing the materials into a rectification system, and removing the raw materials to obtain a single-component perfluoroalkyl iodide product; the specific reaction formula is shown as follows:

。

2. the preparation method of claim 1, wherein the home-made fixed-bed catalyst is prepared by the following steps: and (3) placing the alloy silk screen with the mesh of 100-200 into sufficient diluted hydrochloric acid, soaking for 48 hours, washing for 10-15 minutes by using deionized water, drying for 2 hours at the temperature of 150-200 ℃ in a nitrogen atmosphere, and naturally cooling to room temperature.

3. The production method according to claim 2, wherein the alloy wire mesh is a transition metal alloy.

4. The method of claim 3, wherein the alloy is a copper-zinc alloy catalyst.

5. The production method according to any one of claims 1 to 4, wherein the starting material F (CF)₂CF₂)_nI is pentafluoroiodoethane FCF₂CF₂I or nonafluoroiodobutane F (CF)₂CF₂)₂I。

6. The method according to claim 1, wherein the tetrafluoroethylene is fed at a rate of 0.1 to 10% by mole per hour based on the starting material.

7. The production method according to claim 6, wherein the feeding is stopped when the amount of the tetrafluoroethylene fed is 5 to 60% by mole of the raw material.

8. The process according to any one of claims 1 to 7, wherein the reaction temperature is 80 to 160 ℃ and the pressure is 0.3 to 3.0 MPa.

9. The method according to claim 8, wherein the reaction temperature is 100 to 140 ℃ and the pressure is 0.5 to 2.5 MPa.

Technical Field

The invention belongs to the field of chemical industry and pharmaceutical intermediate preparation, and particularly relates to a preparation method of a relative single-component perfluoroalkyl iodide.

Background

The perfluoroalkyl iodide is a monoiodo perfluoroalkane compound with hydrogen atoms completely substituted by fluorine atoms, is a key intermediate for producing fluorine finishing agent, fluorine-containing surfactant and other fluorine-containing fine chemicals due to the special chemical and physical properties, and downstream products of the compound have important applications in the aspects of light water fire extinguishing agent, magnetic recording material, water and oil repellent fabric finishing agent, paper finishing agent, oilfield chemistry, photosensitive material, high-grade release agent, metal antirust paint, plastic rubber auxiliary agent, medical material and the like, and are widely applied to the fields of industrial production and life consumption.

Generally, the catalyst is prepared by reacting pentafluoroiodoethane serving as an initial polymerization agent with tetrafluoroethylene in the presence of a catalyst at a certain temperature and pressure:

the known synthesis method of perfluoroalkyl iodide adopts kettle type, intermittent type and gas-liquid reaction, and a large number of patents are introduced at home and abroad. The disadvantages are that the reaction is difficult to control and the carbon number distribution of the product is too wide.

CN1535258A discloses a method for continuously producing perfluoroalkyl iodide, which comprises continuously providing perfluoroalkyl iodide as represented by the general formula R_fThe telogen represented by I, tetrafluoroethylene is taken as a main chain material and added into a tubular reactor, and the reactor is filled with a metal catalyst containing powdery spherical metal or sintered metal; the telomerization is carried out at a temperature of 60-160 ℃ and a pressure of 0.1-5 MPa. The method has the disadvantages that the product discharged from the reactor contains a large amount of catalyst, liquid-solid separation is needed, the catalyst cannot be recycled, the cost is high, and the tubular reactor is easy to cause the accumulation of reaction heat, so that the telomerization reaction is difficult to control.

Patent US59292927 combines the reaction preparation and the rectification separation into one, and adopts the rectification reaction process to continuously prepare perfluoroalkyl iodide. The method can avoid the wide distribution of carbon number of the product or prepare a certain intermediate product which can be further reacted with the raw material. The process comprises the following steps: adding pentafluoroethyl iodide into the distillation section of a packed rectifying column reactor, adding a perfluoroethyl iodide solution of an initiator diisopropyl peroxydicarbonate from the top of the tower, and adding tetrafluoroethylene into the middle part of the rectifying column for reaction. The disadvantages are that the process control is complex and the product is not easily purified to higher purity.

CN103880588 discloses a method for preparing perfluoroalkyl iodide by catalytic distillation telomerization, wherein a catalytic distillation tower is composed of a rectifying section, a reaction section, a stripping section and a tower kettle which are connected in sequence from the tower top to the tower bottom, the reaction section is filled with phosphorus bronze wire mesh corrugated filler as a catalyst, and the preparation method comprises the following steps: and respectively and simultaneously continuously adding pentafluoroiodoethane and tetrafluoroethylene into the catalytic distillation tower from the rectifying section and the stripping section for reaction, wherein the molar ratio of the pentafluoroiodoethane to the tetrafluoroethylene is 1: 2-10, the reaction pressure is 0.5-1.4 MPa, and the reaction temperature is 70-100 ℃; continuously leading out the reaction product in the tower kettle to obtain the perfluoroalkyl iodide product. Although the invention effectively avoids the phenomenon that the carbon number distribution of the product is too wide, the content of C4-C8 reaches more than 97 percent, but a single component with higher content still cannot be obtained, for example, the content of C4 in the patent publication is only 42-79 percent, and the total content of C6 and C8 is 21-58 percent.

In particular, none of the above methods is effective in reducing the amount of perfluorooctyl iodide C8 produced. C8 can be converted into perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) through chemical reaction, which have extremely strong persistence and are one of the most difficult-to-decompose organic pollutants, accumulate in organic organisms, have high toxicity and strong long-distance transmission capability, and become a new persistent environmental pollutant after polychlorinated biphenyl, organochlorine pesticide and dioxin.

In 2000 the United states, European Union, etc. began to restrict the production and use of PFOA/PFOS. In the last year, according to the requirements of the ecological environment ministry, from 3 and 26 months in 2019, the production, circulation, use and import and export of perfluorooctyl sulfonic acid and salts thereof and perfluorooctyl sulfonyl fluoride except acceptable use are prohibited.

Disclosure of Invention

In order to solve the problems existing in the method, the invention discloses a preparation method of a relative single-component perfluoroalkyl iodide.

The technical scheme adopted by the invention for realizing the purpose is as follows:

the invention provides a preparation method of a relative single-component perfluoroalkyl iodide, which is characterized in that a self-made fixed-bed catalyst is prepared, and the self-made fixed-bed catalyst is positioned in a stainless steel pressure-resistant reactor 4/5-7 with gas-phase upturning stirring wingsAt the position/8, gas-phase upturning stirring wings are positioned at 1/2-2/3, the reactor is vacuumized and replaced by high-purity nitrogen for 2 times, and the reactor is evacuated until the pressure in the reactor does not drop any more, and the raw material F (CF) is pressed in₂CF₂)_nHeating to a certain temperature, maintaining the pressure of the raw materials, starting a gas-phase upturning stirring wing, introducing tetrafluoroethylene, maintaining the pressure for reaction, stopping feeding when the tetrafluoroethylene is added into the raw materials in a certain proportion, cooling, introducing the materials into a rectification system, and removing the raw materials to obtain a single-component perfluoroalkyl iodide product; the specific reaction formula is shown as follows:

。

the preparation method of the self-made fixed-bed catalyst used by the invention comprises the following steps: and (3) placing the alloy silk screen with the mesh of 100-200 into sufficient diluted hydrochloric acid, soaking for 48 hours, washing for 10-15 minutes by using deionized water, drying for 2 hours at the temperature of 150-200 ℃ in a nitrogen atmosphere, and naturally cooling to room temperature.

Further, the alloy wire mesh is made of transition metal alloy; optimally, the alloy is a copper-zinc alloy catalyst.

Further, the raw material F (CF)₂CF₂)_nI is pentafluoroiodoethane FCF₂CF₂I or nonafluoroiodobutane F (CF)₂CF₂)₂I。

Further, the feeding speed of the tetrafluoroethylene is 0.1-10% of the molar weight of the raw materials per hour.

And further, stopping feeding when the feeding amount of the tetrafluoroethylene is 5-60% of the molar amount of the raw materials.

Further, the reaction temperature is 80-160 ℃, and the pressure is 0.3-3.0 MPa.

Further, the reaction temperature is 100-140 ℃, and the pressure is 0.5-2.5 MPa.

Compared with the prior art, the invention has the following advantages:

1. the invention adopts the self-made fixed-bed catalyst, the contact reaction time of the tetrafluoroethylene and the raw materials is short, and the high-boiling-point product flows to the bottom of the reactor from the wall of the reactor, thereby reducing the secondary reaction of the product and the tetrafluoroethylene as much as possible.

2. The vaporization partial pressure of the raw materials and the products is fully utilized, the contact probability of the raw materials and the tetrafluoroethylene is improved, the contact probability of the products and the tetrafluoroethylene is reduced, and 85-95% of relative single-component perfluoroalkyl iodide is obtained.

3. The equipment used by the invention is simple, convenient to operate, safe and easy to control.

Drawings

FIG. 1 is a pressure-resistant reactor made of stainless steel with stirring blades turned up in the gas phase.

Detailed Description

The technical solution of the present invention is further explained and illustrated by the following specific examples.

Example 1

A. Taking a copper-zinc alloy wire mesh with the diameter of 18cm and the mesh of 160, soaking the copper-zinc alloy wire mesh in sufficient 5 percent of dilute hydrochloric acid, frequently reversing, and taking out the copper-zinc alloy wire mesh after soaking for 48 hours; repeatedly washing with deionized water for 15 minutes; placing the mixture in an oven under the nitrogen atmosphere, drying the mixture for 2 hours at 160 ℃, turning off heating, and naturally cooling to room temperature; opening a middle hole, and installing the reactor shown in figure 1, wherein 1 is a catalyst, 2 is a gas phase upturning stirrer, 3 is a raw material, and 4 is a tetrachloroethylene inlet;

B. evacuating, replacing with high-purity nitrogen for 2 times, evacuating again until the pressure does not drop, sucking 10 kg of pentafluoroiodoethane with the purity of 99.5 percent, heating to the position of 30 percent of the reactor, gradually raising the temperature to 100 ℃, raising the pressure to 1.8MPa, starting a stirrer, introducing tetrafluoroethylene by 80 g/h, maintaining the temperature at 100-110 ℃ and the pressure at 1.8-2.2 MPa, reacting for 15 hours, and adding 1200 g of tetrafluoroethylene in total.

C. After cooling, the material was introduced into a rectification system to remove the raw material pentafluoroiodoethane to obtain 3950 g of relatively single-component nonafluoroiodobutane, as shown in table 1:

TABLE 1

Example 2

A. The same procedure as in the first step of example 1 was repeated.

B. Evacuating, replacing with high-purity nitrogen gas for 2 times, and evacuating until the pressure does not drop. 10 kg of pentafluoroiodoethane of 99.5% purity was sucked into the reactor at 30%. The heating is started and the temperature is gradually increased to 120 ℃, and the pressure is increased by 2.2 MPa. The stirrer was switched on and 85 g/h of tetrafluoroethylene were introduced. The temperature is maintained at 100-110 ℃ and the pressure is maintained at 1.8-2.2 MPa. After 15 hours of reaction, 1275 g of tetrafluoroethylene was added.

C. After cooling, the material was introduced into a rectification system to remove the starting pentafluoroiodoethane, yielding 4202 grams of relatively single-component nonafluoroiodobutane, as shown in table 2:

TABLE 2

Example 3

A. The same procedure as in the first step of example 1 was repeated.

B. Evacuating, replacing with high-purity nitrogen gas for 2 times, and evacuating until the pressure does not drop. 10 kg of nonafluoroiodobutane of 99.1% purity was aspirated to the reactor at 30%. The heating is started and the temperature is gradually increased to 130 ℃, and the pressure is increased by 0.8 MPa. The stirrer was switched on and tetrafluoroethylene was introduced at 95 g/h. The temperature is maintained at 130-135 ℃ and the pressure is maintained at 1.8-2.2 MPa. After 10 hours of reaction, 950 g of tetrafluoroethylene were added.

C. After cooling, the material was introduced into a rectification system to remove the raw material pentafluoroiodoethane to obtain 4025 g of perfluoroiodohexane as a relatively single component, as shown in Table 3:

TABLE 3

Example 4

A. The same procedure as in the first step of example 1 was repeated.

B. Evacuating, replacing with high-purity nitrogen gas for 2 times, and evacuating until the pressure does not drop. 10 kg of nonafluoroiodobutane of 99.1% purity was aspirated to the reactor at 30%. The heating is started and the temperature is gradually increased to 120 ℃, and the pressure is increased by 0.6 MPa. The stirrer was switched on and tetrafluoroethylene was introduced at 90 g/h. The temperature is maintained at 120-125 ℃ and the pressure is maintained at 0.6-0.8 MPa. After 12 hours of reaction, 1080 g of tetrafluoroethylene was added.

C. After cooling, the material was introduced into a rectification system to remove the raw material pentafluoroiodoethane to obtain 4477 g of a relatively single-component perfluoroiodohexane as shown in table 4:

TABLE 4

Comparative example 1

A10L stainless steel vertical reaction kettle is added with 80g of 400-mesh copper powder. The autoclave was evacuated to replace with high-purity nitrogen gas for 2 times and then evacuated until the pressure did not decrease. 10 kg of pentafluoroiodoethane is pressed in, stirring is started, the temperature is raised to start reaction, when the temperature is raised to 110 ℃, the pressure is about 2MPa, tetrafluoroethylene is led in until the pressure is 2.4MPa, when the pressure in the kettle is lowered to 2.0MPa, the operation is repeated, 1.05 kg of tetrafluoroethylene is added in total, the temperature is reduced, and unreacted pentafluoroiodoethane is recovered, so that 2100g of perfluoroiodoethane is obtained. The product was subjected to alkaline cleaning and dehydration treatment, and the results are shown in table 5:

TABLE 5

Comparative example 2

The internal diameter of the catalytic reaction rectifying tower is 100cm, and the filling specific surface area of the reaction section is 125m² /m³The height of the copper wire mesh corrugated packing is 2m, pentafluoroethyl iodide is continuously added from a rectifying section at the upper part of the reaction section, and gas-phase tetrafluoroethylene is continuously added from a stripping section at the lower part of the reaction section.

The reaction conditions are as follows: the mol ratio of pentafluoroiodoethane to tetrafluoroethylene is 1: 5; the reaction pressure is 1.0 MPa; the temperature of the reaction section is 70 ℃, the low boiling point fraction containing tetrafluoroethylene is extracted from the top of the rectifying section at the upper part, and the perfluoroalkyl iodine crude product is continuously discharged from the bottom of the stripping section at the lower part. The samples were analyzed and the results are shown in Table 6:

TABLE 6

Comparative example 3

A10L stainless steel vertical reaction kettle is added with 80g of 400-mesh copper-zinc alloy powder. The autoclave was evacuated to replace with high-purity nitrogen gas for 2 times and then evacuated until the pressure did not decrease. 10 kg of pentafluoroiodoethane is pressed in, stirring is started, the temperature is raised to start the reaction, when the temperature is raised to 110 ℃, the pressure is about 2MPa, tetrafluoroethylene is led in until the pressure is 2.4MPa, the operation is repeated when the pressure in the kettle is reduced to 2.0MPa, 1.12 kg of tetrafluoroethylene is added in total, and the temperature is reduced to recover the unreacted pentafluoroiodoethane, so that 2250g of perfluoroiodoethane is obtained. The product was subjected to alkaline cleaning and dehydration treatment, and the results are shown in table 7:

TABLE 7

Comparative example 4

The internal diameter of the catalytic reaction rectifying tower is 100cm, and the filling specific surface area of the reaction section is 125m² /m³The copper wire mesh (the copper wire mesh is pretreated, namely is soaked in sufficient 5 percent dilute hydrochloric acid and is frequently reversed, and is taken out after being soaked for 48 hours, is repeatedly washed by deionized water for 15 minutes, is placed in a drying oven under the nitrogen atmosphere, is dried for 2 hours at 160 ℃, is closed to heat and is naturally cooled to room temperature), the height of the corrugated packing is 2m, pentafluoroethyl iodide is continuously added from a rectifying section at the upper part of a reaction section, and gas-phase tetrafluoroethylene is continuously added from a stripping section at the lower part of the reaction section;

the reaction conditions are as follows: the mol ratio of pentafluoroiodoethane to tetrafluoroethylene is 1: 5; the reaction pressure is 1.0 MPa; the temperature of the reaction section is 70 ℃, the low boiling point fraction containing tetrafluoroethylene is extracted from the top of the rectifying section at the upper part, and the perfluoroalkyl iodine crude product is continuously discharged from the bottom of the stripping section at the lower part. The samples were analyzed and the results are shown in Table 8:

TABLE 8