Preparation method of phosphorus trifluoride

Abstract

The invention relates to the technical field of chemical preparation, in particular to a preparation method of phosphorus trifluoride, which comprises the following steps: step 1, preparing reactants: preparing phosphorus pentoxide and pure fluorine gas; 2, mixing reactants: in a proper reaction container, mixing phosphorus pentoxide with pure fluorine gas; step 3, controlling the reaction conditions of reactants: ensuring that the reaction is carried out at proper temperature and pressure so as to promote the smooth proceeding of the reaction; and 4, separating the product to obtain phosphorus trifluoride. The method comprises the following steps: putting phosphorus pentoxide into a dry container, preparing a storage tank filled with fluorine gas, putting the prepared phosphorus pentoxide into a reaction container, introducing the dry fluorine gas from the storage tank, carrying out a reaction at high temperature and high pressure, and after the reaction is completed, adding the fluorine gas into the reaction container, phosphorus trifluoride and a byproduct oxyfluoride are separated through a physical method (distillation or condensation), so that the process is simple, and the reaction conversion rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical preparation, and specifically provides a method for preparing phosphorus trifluoride. Background Art

[0002] Phosphorus trifluoride is an inorganic compound. It is a colorless, odorless and toxic gas under normal temperature and pressure, and a colorless and transparent liquid in the liquid state. It can react with water to form phosphorous acid and hydrogen fluoride. Phosphorus trifluoride is commonly used as a reaction reagent in organic synthesis and is widely used in chemical laboratories. It plays an important role in the formation of fluorinated hydrocarbon compounds, fluorination reactions of aromatic compounds, and reactions of amines with acid anhydrides.

[0003] Currently, the process for preparing phosphorus trifluoride is relatively complex. The conversion rate of the reactants is low after the mixing reaction is completed, and it is difficult to remove impurities. Therefore, there is a need to provide a method for preparing phosphorus trifluoride with a simple production process, high reaction conversion rate, and easy purification. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] In view of the deficiencies of the prior art, the present invention provides a method for preparing phosphorus trifluoride, which has the advantages of a simple production process, high reaction conversion rate, and easy purification, and solves the above problems.

[0006] (II) Technical Solutions

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing phosphorus trifluoride includes the following steps:

[0009] Step 1: Prepare the reactants: Prepare phosphorus pentoxide and pure fluorine gas.

[0010] Step 2: Mix the reactants: In a suitable reaction vessel, mix phosphorus pentoxide and pure fluorine gas.

[0011] Step 3: Control the reaction conditions of the reactants: Ensure that the reaction proceeds under appropriate temperature and pressure to promote the smooth progress of the reaction.

[0012] Step 4: Separate the product to obtain phosphorus trifluoride.

[0013] Preferably, in Step 1, place phosphorus pentoxide in a dry container for storage, and prepare a storage tank filled with fluorine gas.

[0014] Preferably, in Step 2, put the prepared phosphorus pentoxide into a reaction vessel, and introduce dry fluorine gas from a storage tank, ensuring that the reaction vessel is well-sealed to prevent fluorine gas leakage. Since fluorine gas is a very reactive gas, the reaction may need to be carried out in a special reaction device. Usually, place the phosphorus pentoxide in a suitable reaction vessel and then slowly introduce fluorine gas. The reaction device needs to have good airtightness and corrosion resistance to ensure the safe progress of the reaction and prevent fluorine gas leakage.

[0015] Preferably, the reaction condition in Step 3 is high temperature and high pressure. Since fluorine gas has extremely strong corrosiveness and toxicity, the experiment should be carried out under strict safety conditions, such as in a fume hood and wearing appropriate protective equipment.

[0016] Preferably, in Step 4, after the reaction is completed, separate phosphorus trifluoride and the by-product oxygen fluoride by physical methods (distillation or condensation).

[0017] Preferably, for a high-concentration mixture of phosphorus trifluoride and oxygen fluoride, direct recovery can be carried out by cryogenic separation. This method utilizes the volatility differences of different compounds at different temperatures to separate them by low-temperature cooling.

[0018] Preferably, the separated product in Step 4 can also be separated by chemical separation methods, adsorption separation methods, and membrane separation methods.

[0019] (III) Beneficial Effects

[0020] Compared with the prior art, the present invention provides a method for preparing phosphorus trifluoride, which has the following beneficial effects:

[0021] 1. In the present invention, put the phosphorus pentoxide into a dry container, and prepare a storage tank filled with fluorine gas. Put the prepared phosphorus pentoxide into a reaction vessel, and introduce dry fluorine gas from the storage tank, ensuring that the reaction vessel is well-sealed to prevent fluorine gas leakage. React under high temperature and high pressure. After the reaction is completed, separate phosphorus trifluoride and the by-product oxygen fluoride by physical methods (distillation or condensation), thereby making the process simple and having a high reaction conversion rate.

[0022] 2. For a high-concentration mixture of phosphorus trifluoride and oxygen fluoride, direct recovery can be carried out by cryogenic separation. This method utilizes the volatility differences of different compounds at different temperatures to separate them by low-temperature cooling. Specific Embodiments

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] The present invention relates to a method for preparing phosphorus trifluoride, comprising the following steps:

[0025] Step 1: Prepare reactants: Prepare phosphorus pentoxide and pure fluorine gas;

[0026] Place the phosphorus pentoxide in a dry container for storage, and prepare a storage tank filled with fluorine gas;

[0027] Step 2: Mix the reactants: In a suitable reaction container, mix the phosphorus pentoxide and pure fluorine gas;

[0028] Put the prepared phosphorus pentoxide into the reaction container, and introduce dry fluorine gas from the storage tank, ensuring that the reaction container is well sealed to prevent the leakage of fluorine gas. Since fluorine gas is a very reactive gas, the reaction may need to be carried out in a special reaction device. Usually, the phosphorus pentoxide is placed in a suitable reaction container, and then fluorine gas is slowly introduced. The reaction device needs to have good sealing performance and corrosion resistance to ensure the safe progress of the reaction and prevent the leakage of fluorine gas;

[0029] Step 3: Control the reaction conditions of the reactants: Ensure that the reaction is carried out under appropriate temperature and pressure to promote the smooth progress of the reaction;

[0030] The reaction conditions are high temperature and high pressure. Since fluorine gas has extremely strong corrosiveness and toxicity, the experiment should be carried out under strict safety conditions, such as in a fume hood and wearing appropriate protective equipment;

[0031] Step 4: Separate the product to obtain phosphorus trifluoride;

[0032] Example 1:

[0033] After the reaction is completed, phosphorus trifluoride and by-product oxygen fluoride are separated by physical methods (distillation or condensation). For a high-concentration mixture of phosphorus trifluoride and oxygen fluoride, direct recovery can be carried out by cryogenic separation. This method utilizes the volatility differences of different compounds at different temperatures and separates them by low-temperature cooling. The separated products can also be separated by chemical separation methods, adsorption separation methods, and membrane separation methods.

[0034] Example 2:

[0035] Chemical separation method: It includes chemical reaction method: converting phosphorus trifluoride and oxyfluoride into different compounds through chemical reactions to achieve separation;

[0036] Reaction with water: Phosphorus trifluoride reacts with water to produce phosphoric acid and hydrofluoric acid, while oxyfluoride reacts with water to produce different products. By controlling the reaction conditions, these two compounds can be separated;

[0037] Reaction with base: Phosphorus trifluoride and oxyfluoride react with base to produce different salts, and they can be separated by filtration or extraction methods.

[0038] Example Three:

[0039] Adsorption separation method: Selective adsorption: Using specific adsorbents such as activated carbon or molecular sieve to selectively adsorb phosphorus trifluoride or oxyfluoride. By changing the temperature or pressure, the regeneration of the adsorbent and the recovery of the target compound can be achieved.

[0040] Example Four:

[0041] Membrane separation method: Permeation membrane separation: Utilizing the selective permeability of the permeation membrane to separate phosphorus trifluoride and oxyfluoride. This method is applicable to low-concentration mixtures. By adjusting the pore size of the membrane and operating conditions, efficient separation can be achieved.

[0042] The beneficial effects of the present invention are: By placing phosphorus pentoxide in a dry container and preparing a storage tank filled with fluorine gas, putting the prepared phosphorus pentoxide into the reaction container and introducing dry fluorine gas from the storage tank, ensuring that the reaction container is well sealed to prevent fluorine gas leakage, reacting under high temperature and high pressure, and separating phosphorus trifluoride and the by-product oxyfluoride by physical methods (distillation or condensation) after the reaction is completed, thus making the process simple and having a high reaction conversion rate.

[0043] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing phosphorus trifluoride, characterized in that: The following steps are involved: Step 1: Prepare reactants: prepare phosphorus pentoxide and pure fluorine gas; Step 2: Mixing reactants: In a suitable reaction vessel, mix phosphorus pentoxide and pure fluorine gas; Step 3: Control the reaction conditions of the reactants: ensure that the reaction is carried out at appropriate temperature and pressure to promote the smooth progress of the reaction; Step 4: Separate the product to obtain phosphorus trifluoride.

2. A method for preparing phosphorus trifluoride according to claim 1, characterized in that: In the step 1, phosphorus pentoxide is placed in a dry container for storage, and a storage tank filled with fluorine gas is prepared.

3. A method for preparing phosphorus trifluoride according to claim 1, characterized in that: In the step 2, the prepared phosphorus pentoxide is placed in a reaction vessel, and dry fluorine gas is introduced from a storage tank, ensuring that the reaction vessel is well sealed to prevent fluorine gas leakage, thereby ensuring the safety of the reaction.

4. A method for preparing phosphorus trifluoride according to claim 1, characterized in that: The reaction conditions of step three are high temperature and high pressure. Since fluorine gas is extremely corrosive and toxic, the experiment should be carried out under strict safety conditions, such as in a fume hood, and wearing appropriate protective equipment.

5. A method for preparing phosphorus trifluoride according to claim 1, characterized in that: In step 4, after the reaction is completed, phosphorus trifluoride and the by-product oxyfluoride are separated by a physical method (distillation or condensation).

6. A method for preparing phosphorus trifluoride according to claim 5, characterized in that: High concentrations of phosphorus trifluoride and oxyfluoride mixtures can be directly recovered by cryogenic separation, which uses the difference in volatility of different compounds at different temperatures to separate them by low temperature cooling.

7. A method for preparing phosphorus trifluoride according to claim 1, characterized in that: The product separation in step 4 can also be carried out by chemical separation, adsorption separation and membrane separation.