阅读说明：本技术 一种有机磷化合物的生产方法 (Production method of organic phosphorus compound ) 是由 姜友法 王宝林 范剑峰 徐华星 宋晓春 李纪平 于 2020-08-11 设计创作，主要内容包括：本发明公开了一种有机磷化合物的生产方法,采用合适、安全的捕集剂能直接对高温可燃合成气体进行多级捕集,得到的捕集液经精馏分离出原料三氯化磷与产物甲基二氯化膦,塔釜捕集剂经蒸馏回收后能继续在系统内循环套用,解决了原工艺安全要求高、工业化实施难度高的问题。本发明能够安全的在相对较高温度下直接对高温可燃合成气体进行冷却,降低了合成工艺对生产装置制冷的要求,具有能耗低、易工业化实施的特点；主要用以解决当前甲基二氯化膦生产过程中安全要求高、能耗高、成本高的问题。(The invention discloses a method for producing an organic phosphorus compound, which adopts a proper and safe trapping agent to directly carry out multistage trapping on high-temperature combustible synthetic gas, the obtained trapping liquid is rectified to separate phosphorus trichloride and a product, namely, phosphine methyldichloride, and the trapping agent at the bottom of a tower can be continuously recycled in a system after being distilled and recovered, thereby solving the problems of high safety requirement of the original process and high difficulty in industrial implementation. The invention can safely and directly cool the high-temperature combustible synthesis gas at relatively high temperature, reduces the requirement of the synthesis process on the refrigeration of a production device, and has the characteristics of low energy consumption and easy industrial implementation; mainly used for solving the problems of high safety requirement, high energy consumption and high cost in the current production process of the methyl phosphine dichloride.)

1. A method for producing organic phosphorus compound, raw materials of phosphorus trichloride and catalyst carbon tetrachloride are mixed and then carry out synthetic reaction with methane to obtain high-temperature combustible gas, and the high-temperature combustible gas obtained by synthesis is directly cooled by adopting a trapping agent, which is characterized by comprising the following steps:

(1) cooling and condensing: extracting the synthesized high-temperature combustible gas, and conveying the gas to a quenching tower for cooling and condensing to obtain condensate and the high-temperature combustible gas which is still gaseous after cooling;

(2) trapping: conveying the high-temperature combustible gas which is still gaseous after being cooled in the step (1) into a buffer tank, conveying the gas into a multistage trapping tower after buffering, wherein the trapping tower is a falling film absorption tower taking a trapping agent as a medium, the trapping agent is directly contacted with the high-temperature combustible gas, the high-temperature combustible gas is subjected to multistage trapping by adopting the trapping agent, so that a trapped liquid and tail gas are obtained, and the tail gas is recovered;

(3) and (3) post-treatment: and (3) carrying out post-treatment on the condensate obtained in the step (1) and the capture liquid obtained in the step (2) through a rectifying tower, separating out phosphorus trichloride and a product phosphine methyl dichloride at the tower top, and distilling and recycling the capture agent obtained at the tower bottom for recycling.

2. The production method according to claim 1, wherein in the step (1), a trapping agent with the temperature of-20-30 ℃ is pumped into the quenching tower, and the trapping agent is sprayed to cool the synthesized high-temperature combustible gas in a vaporization mode.

3. The production method according to claim 1, wherein in the step (2), a trapping agent pre-cooled to-20-30 ℃ is pumped into the falling film absorption tower, and the high-temperature combustible gas still in a gaseous state after temperature reduction is trapped by a multi-stage falling film absorption tower with the trapping agent as a medium.

4. The production method according to any one of claims 2 or 3, wherein the trapping agent is a mixture of one, two or more compounds having a structural formula of CxHyRz, which are mixed in any ratio, wherein: x is the number 1, 2, 3, 4, 5, 6, 7, 8, 9, y, z is the number 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and the following relationships are satisfied: 2x +2 ═ y + z or 2x ═ y + z; r is fluorine, chlorine, bromine or iodine.

5. The production method according to claim 4, wherein the trapping agent is a mixture of one, two or more of carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, trichloroethylene, tetrachloroethylene and dichloropropane, which are incombustible and in which pentachlorocyclopropane is mixed in any proportion.

6. The production method according to claim 1, wherein in the step (2), a refrigerant coil is arranged in the falling film absorption tower to cool the obtained collected liquid, and the temperature of the refrigerant in the refrigerant coil is-20 to 30 ℃.

Technical Field

The present invention relates to a process for producing an organophosphorus compound.

Background

Methyl phosphine dichloride is a basic organophosphorus compound having the structural formula:the pure product is colorless transparent liquid. The methyl phosphine dichloride is extremely active in chemical property, extremely easy to react with water and oxygen in the air, easy to be natural, difficult to store and difficult to transport, so that the methyl phosphine dichloride cannot be directly purchased and obtained in the market. Meanwhile, the methyl phosphine dichloride is an organophosphorus intermediate with wide application, and chemicals such as pesticides, medicines, flame retardants and the like can be synthesized from the organic phosphorus intermediate. The research on the synthesis of the methyl phosphine dichloride is more in 70-80 years abroad, and the synthesis route is mainly divided into a liquid phase method and a gas phase method. The reaction conditions of the liquid phase method are relatively mild, the operation difficulty is small, but the synthesis route is long, the cost of required raw materials is high, and the environmental pollution is serious due to a large amount of byproducts (magnesium salts or aluminum salts). The gas phase method has short reaction route, high atom economy, low cost and easy obtaining of raw materials, the route is that the added phosphorus trichloride is heated to 500-600 ℃ under the condition of the existence of a catalyst, the reaction retention time is 0.1-0.9S, then the reaction product is cooled to-50-60 ℃, the gas after gas-liquid separation is dried to remove hydrogen chloride and then directly used, and the condensed liquid mainly contains threePhosphorus chloride and methyl phosphine dichloride, wherein the content of the methyl phosphine dichloride is 10-30 percent, and the cooling liquid is rectified to obtain the methyl phosphine dichloride with the content of 97 percent.

The gas phase process route was developed and successfully commercialized by Hoechst (Hoechst) in germany, in which he owns a number of patents, mainly DE2629299, DE2701389, US4104304, etc., and so far only he has realized the industrialization of this route worldwide. In the description of patent US4104304, raw material phosphorus trichloride and catalyst carbon tetrachloride are mixed according to a certain proportion, and after being vaporized by a preheater, they are fed into a tubular reactor made of hastelloy material together with methane to make reaction, in which the tubular reactor is divided into two sections, and a special gas-solid separation device is added in the middle and outlet, after the synthetic gas is discharged from second gas-solid separator, it is fed into a chilling device to quickly cool the reaction system to below-50 deg.C, and can convert the synthetic gas into liquid phase, and the cooled liquid is phosphorus trichloride solution whose content is 10% -30% of methyl phosphine dichloride, and the cooling liquid is rectified to obtain methyl phosphine dichloride whose content is 97%.

The difficulty of the industrial implementation of the process mainly comprises the following steps: 1. the problem of corrosion of the material of the reactor under extreme conditions such as high temperature and strong acid is solved; 2. the description of a gas-solid separation device under high temperature conditions in the patent is too simple, so that the problem of removing insoluble impurities in the synthesis process needs to be solved in the industrial implementation of a gas phase method; 3. the high-temperature synthesis gas (containing methane) needs to be rapidly cooled from 500-600 ℃ to-50-60 ℃ in a short time at the outlet of the reactor, the safety of combustible synthesis gas under the high-temperature condition and the high cost and high energy consumption of an industrial refrigerating device at-50-60 ℃ are also difficulties for hindering the industrial implementation of a gas phase method. In view of the above, there is a time of about 40 years from 1978 to the present in the world, and some and only one of hurst companies have achieved industrialization of the gas phase route of methyl phosphine dichloride, so how to simplify the process can become easy to implement and operate is a very valuable topic.

Disclosure of Invention

The invention provides a method for producing an organic phosphorus compound, which is mainly used for solving the problems that in the prior art, high-temperature synthesis gas (containing methane) needs to be rapidly cooled to-50 ℃ to-60 ℃ from 500 ℃ to 600 ℃ in a short time at an outlet of a reactor, the safety requirement of combustible synthesis gas under the high-temperature condition is high, and an industrial refrigerating device at-50 ℃ to-60 ℃ has large equipment investment, high cost and high energy consumption.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for producing organic phosphorus compound, raw materials of phosphorus trichloride and catalyst carbon tetrachloride are mixed and then carry out synthetic reaction with methane to obtain high-temperature combustible gas, and the high-temperature combustible gas obtained by synthesis is directly cooled by adopting a trapping agent, which is characterized by comprising the following steps:

(1) cooling and condensing: extracting the synthesized high-temperature combustible gas, and conveying the gas to a quenching tower for cooling and condensing to obtain condensate and the high-temperature combustible gas which is still gaseous after cooling;

(2) trapping: conveying the high-temperature combustible gas which is still gaseous after being cooled in the step (1) into a buffer tank, conveying the gas into a multistage trapping tower after buffering, wherein the trapping tower is a falling film absorption tower taking a trapping agent as a medium, the trapping agent is directly contacted with the high-temperature combustible gas, the high-temperature combustible gas is subjected to multistage trapping by adopting the trapping agent, so that a trapped liquid and tail gas are obtained, and the tail gas is recovered;

(3) and (3) post-treatment: and (3) carrying out post-treatment on the condensate obtained in the step (1) and the capture liquid obtained in the step (2) through a rectifying tower, separating out raw materials of phosphorus trichloride and a product of phosphine methyldichloride from the tower top, feeding the raw materials of phosphorus trichloride and the product of phosphine methyldichloride into a purifying tower for further separation, and distilling and recycling the capture agent obtained from the tower bottom.

In the technical scheme, in the step (1), a trapping agent with the temperature of-20-30 ℃ (preferably-20 to-10 ℃) is pumped into a quenching tower, and the trapping agent is sprayed to cool the synthesized high-temperature combustible gas in a vaporization mode.

In the technical scheme, in the step (2), a trapping agent precooled to-20-30 ℃ (preferably-20 to-10 ℃) is pumped into the falling film absorption tower, and the high-temperature combustible gas still in a gaseous state after being cooled is trapped by a multistage falling film absorption tower with the trapping agent as a medium.

In the above technical scheme, in the step (2), the falling film absorption tower is provided with a refrigerant coil pipe for cooling the obtained capture liquid, and the temperature of the refrigerant in the refrigerant coil pipe is-20 to 30 ℃, preferably-20 to-10 ℃.

In the technical scheme, the trapping agent is a mixture formed by mixing any one, two or more than two compounds with a structural formula of CxHyRz in any proportion, wherein: x is the number 1, 2, 3, 4, 5, 6, 7, 8, 9, y, z is the number 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and the following relationships are satisfied: 2x +2 ═ y + z or 2x ═ y + z; r is fluorine, chlorine, bromine or iodine.

In the above technical solution, the trapping agent is preferably a mixture of one, two or more of carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, trichloroethylene, tetrachloroethylene and dichloropropane, which have incombustible characteristics, and which are mixed in any proportion.

The technical scheme of the invention has the advantages that: the appropriate and safe trapping agent can be used for directly performing multistage trapping on the high-temperature combustible synthetic gas, the obtained trapping liquid is rectified to separate the phosphorus trichloride as the raw material and the methyl phosphine dichloride as the product, and the trapping agent at the tower bottom can be recycled in the system after being distilled and recovered, so that the problems of high safety requirement of the original process and high difficulty in industrial implementation are solved. The invention can safely and directly cool the high-temperature combustible synthesis gas at relatively high temperature, reduces the requirement of the synthesis process on the refrigeration of a production device, and has the characteristics of low energy consumption and easy industrial implementation.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

Detailed Description

The following detailed description of the embodiments of the present invention is provided, but the present invention is not limited to the following descriptions:

example 1

A set of synthetic columns made of DN25 hastelloy materials are filled with 4-6mm nickel balls, and the length of each column is 1 m. The raw material composition is a mixture of carbon tetrachloride and phosphorus trichloride, wherein the concentration of the carbon tetrachloride is 7%. And opening a methane inlet valve at the lower part of the synthesis column to control the methane inlet speed to be 120 liters/hour, heating the synthesis column to 580 ℃ in the methane atmosphere, pumping the mixture of carbon tetrachloride and phosphorus trichloride into the synthesis column from a feed inlet at the lower part of the synthesis column after the temperature is stable, wherein the feed speed is 110 grams/hour, and extracting the synthesized high-temperature combustible gas from the upper part of the synthesis column.

Extracting the synthesized high-temperature combustible gas, then feeding the gas into a quenching tower, pumping carbon tetrachloride precooled to-20 to-25 ℃ by the quenching tower at a speed of 62.5 g/h, cooling and condensing to obtain condensate, wherein part of the gas is still gaseous high-temperature combustible gas after being cooled. The high-temperature combustible gas enters a first-stage collecting tower and a second-stage collecting tower after being buffered by a buffer tank, 1500 g of carbon tetrachloride is respectively added into the first-stage collecting tower and the second-stage collecting tower, and the collecting temperature is controlled to be-20 to-25 ℃ by cooling a jacket.

After the high-temperature combustible gas is cooled, condensed and collected with raw materials of phosphorus trichloride and a product of phosphine methyl dichloride (shown in a flow chart in figure 1), and continuously operated for 24 hours, 3296.4 g of condensate is collected from the bottom of a quenching tower, 1913.3 g of collected liquid of a first-stage collecting tower and 1717.6 g of collected liquid of a second-stage collecting tower, and the weight yield is 91.94%.

Example 2

The synthesis conditions are the same as example 1, the trapping agent is carbon tetrachloride, the precooling temperature of the carbon tetrachloride is increased to-10 to-15 ℃, the trapping temperature of the trapping tower is increased to-10 to-15 ℃, after the continuous operation for 24 hours, 3135.6 g of condensate is collected from the bottom of the quenching tower, 1835.3 g of first-stage trapping tower collected liquid, 1697.3 g of second-stage trapping tower collected liquid, and the weight yield is 82.13%.

Example 3

The synthesis conditions are the same as example 1, the trapping agent is tetrachloroethylene, the precooling temperature of the tetrachloroethylene is-20 to-25 ℃, the trapping temperature of the trapping tower is increased to-20 to-25 ℃, and after the continuous operation is carried out for 24 hours, 3335.4 g of condensate is collected from the bottom of the quenching tower, 1907.5 g of first-stage trapping tower collected liquid, 1723.4 g of second-stage trapping tower collected liquid, and the weight yield is 93.42%.

Example 4

The synthesis conditions are the same as example 1, the trapping agent is tetrachloroethylene, the precooling temperature of the tetrachloroethylene is-10 to-15 ℃, the trapping temperature of the trapping tower is increased to-10 to-15 ℃, and after the continuous operation is carried out for 24 hours, 3283.4 g of condensate is collected from the bottom of the quenching tower, 1901.7 g of the first-stage trapping tower collected liquid, 1717.9 g of the second-stage trapping tower collected liquid, and the weight yield is 91.02%.

Example 5

The synthesis conditions are the same as example 1, the trapping agent is tetrachloroethane, the precooling temperature of the tetrachloroethane is-20 to-25 ℃, the trapping temperature of the trapping tower is increased to-20 to-25 ℃, and after the continuous operation is carried out for 24 hours, 3480.4 g of condensate is collected from the bottom of the quenching tower, 1824.2 g of first-stage trapping tower collected liquid, 1711.8 g of second-stage trapping tower collected liquid, and the weight yield is 95.32%.

The above examples are only for illustrating the technical concept and features of the present invention, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Example 6

The synthesis conditions are the same as example 1, the trapping agent is pentachlorocyclopropane, the precooling temperature of the pentachlorocyclopropane is-20 to-25 ℃, the trapping temperature of the trapping tower is increased to-20 to-25 ℃, and after the continuous operation is carried out for 24 hours, 3375.1 g of condensate is extracted from the bottom of the quenching tower, 1883.7 g of trapping liquid of the first-stage trapping tower, 1769.4 g of trapping liquid of the second-stage trapping tower, and the weight yield is 95.77%.

The above examples are only for illustrating the technical concept and features of the present invention, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.