CN111848672B - A kind of continuous synthesis process of tetramethyl phosphonate succinate - Google Patents

Abstract

The invention discloses a continuous synthesis process of tetramethyl phosphonic acid succinate, comprising the following steps: continuous dimethyl maleate and dimethyl phosphite in a molar ratio of 1:1.02-1.20 It is transported into the pre-mixer for full pre-mixing, the residence time is 20-40 s, and then mixed with the sodium methoxide catalyst through the pipeline to enter the tubular reactor for preliminary reaction; then it enters the reactor from the bottom of the kettle reactor; the material is in the tubular reactor. The residence time in the reactor is 6-12min; the reaction temperature is 25-35°C; after the material undergoes preliminary pipeline reaction, it enters into each kettle type reactor in series, and sodium methoxide catalyst is added to ensure the reaction rate; the material is in the series kettle type The residence time in the reactor is 0.5-1.0h; the reaction temperature is 25-35°C; the reaction product tetramethyl phosphonic acid succinate is obtained in the kettle type reactor. The invention not only increases the production efficiency, but also effectively controls the reaction temperature, solves the heat exchange problem that is difficult to solve in the strong exothermic reaction, and has stable product quality.

Description

A kind of continuous synthesis process of tetramethyl phosphonate succinate

technical field

The invention relates to the field of chemical synthesis, in particular to a kind of tetramethyl phosphonic acid succinate and a synthesis process, in particular to a kind of continuous synthesis of dimethyl maleate and dimethyl phosphite to synthesize tetramethyl phosphonic acid succinate The addition reaction of methyl esters.

Background technique

Tetramethyl phosphonate succinate, also known as tetraalkyl phosphonate succinate, is a yellow viscous liquid, which can be used as an important synthetic raw material and intermediate for water treatment agent PBTCA.

The traditional production method of tetramethyl phosphonic acid succinate mostly uses dimethyl maleate and dimethyl phosphite as raw materials, in a kettle reactor, by dropwise addition of sodium methoxide-methanol solution, in sodium methoxide. The addition reaction takes place under the catalysis of , and the reaction time is about 15 hours, and a large amount of heat is released during the reaction process, making it difficult to control the reaction temperature smoothly, resulting in a large number of side reactions, causing environmental pollution.

In order to control the reaction temperature, predecessors have taken many measures in both process and engineering. But these measures have failed to solve the problem fundamentally, and have their own shortcomings and drawbacks. For example, it is common in the industry to dilute the reaction mixture with a large amount of solvent. And take the measures of adding materials dropwise, but after the reaction, the solvent should be recovered by distillation, and the production energy consumption will be increased.

At present, there is no relevant disclosed preparation method for continuously generating tetramethyl phosphonic acid succinate by using dimethyl maleate and dimethyl phosphite as raw materials under the catalysis of catalyst sodium methoxide.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is to provide a method for the continuous synthesis of dimethyl maleate and dimethyl phosphite to synthesize tetramethyl phosphonic acid succinate, thereby reducing side reactions and shortening the reaction time.

The technical scheme of the present invention is that a continuous synthesis process of tetramethyl phosphonate succinate comprises the following steps:

1) Continuously transport dimethyl maleate and dimethyl phosphite in a molar ratio of 1:1.02-1.20 into a premixer for full premixing, and then mix with sodium methoxide catalyst through a pipeline into a tubular The reactor is used for preliminary reaction; then it enters the reactor from the bottom of the tank reactor; The ratio is 0.5%-1%; the residence time of the material in the tubular reactor is 6-12min; the reaction temperature is 25-35℃;

2) After the material undergoes preliminary pipeline reaction, it enters the first tank reactor in series, and sodium methoxide catalyst is added to ensure the reaction rate; the residence time of the material in the first tank reactor connected in series is 0.5-1.0h; the reaction The temperature is 25～35℃; the ratio of catalyst volume to raw material volume is 0.5%-1%;

3) Enter the second tank reactor in series, and add sodium methoxide catalyst to ensure the reaction rate; the residence time of the material in the second tank reactor connected in series is 0.5 ~ 1.0h; the reaction temperature is 25 ~ 35 ℃; the catalyst volume The volume ratio to the raw material is 1%-3%; the reaction product tetramethyl phosphonate succinate is obtained in the tank reactor.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, in step 1), the residence time of the material in the tubular reactor is 6-12 min.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, in step 2), the residence time of the material in the series-connected tank reactor is 0.5-1 h. In step 3), the material is in the second tank reactor connected in series, and the residence time is 0.5-1 h.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, the sodium methoxide catalyst described in step 1) and step 2) is a methanol solution of sodium methoxide.

Further, the mass concentration of sodium methoxide in the methanol solution of sodium methoxide is 20-35%.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, the tank reactor in step 2) is provided with a stirrer. The stirring speed is preferably 60r-180r/min.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, the tubular reactor is provided with a heat exchange coil, the coil is a steel pipe spiral structure, and the coil passes through Industrial chilled water; a heat exchange interlayer is arranged inside the kettle-type reactor, and industrial chilled water is introduced for heat exchange.

In order to remove the reaction heat in time, a special heat exchange coil is installed in the tubular reactor. The coil is a stainless steel pipe spiral structure. The industrial chilled water is passed through the coil at a temperature of -5-4 °C to take away the heat generated by the reaction; the kettle There is a heat exchange interlayer inside the reactor, which can be passed into industrial chilled water at a temperature of -5-4°C for heat exchange. In addition, an external heat exchange device can be added according to the reaction heat release, and the reactor can be controlled to react at 25-35°C. Improve the reaction selectivity from 90-93% to 97-99%.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, step 1) the stay of dimethyl maleate and dimethyl phosphite in the premixer The time is 10-50s.

According to the continuous synthesis process synthesis process of tetramethyl phosphonate succinate of the present invention, preferably, the flow rate of the catalyst in step 1) is 0.2-0.8L/h; in step 2) the catalyst is in the first kettle The flow rate in the reactor was 0.2-0.8 L/h; the flow rate of the catalyst in the second tank reactor was 0.4-2.4 L/h.

In view of the shortcomings of the prior art, in order to realize the continuous synthesis of dimethyl maleate and dimethyl phosphite to synthesize tetramethyl phosphonate succinate, and effectively control the reaction temperature, avoid the generation of side reactions, and reduce the The reaction production time is increased, and the production efficiency is increased. The invention provides a process for continuously synthesizing tetramethyl phosphonic acid succinate. A plurality of different reactors are used in series, and the reaction materials are reacted in stages. The amount of heat area reduces the reaction time, and at the same time controls the reaction temperature, reduces the production of reaction by-products, and the product quality is stable. The production efficiency is improved, the operation and production are simplified, and the environmental pollution caused by starting and stopping is suppressed.

Beneficial effects of the present invention:

Compared with the traditional production process, the continuous synthesis of tetramethyl phosphonate succinate not only increases the production efficiency, but also effectively controls the reaction temperature, solves the heat exchange problem that is difficult to solve in the strong exothermic reaction, and avoids the smooth flow of heat. Dimethyl butenedioate undergoes an addition reaction by itself under high temperature conditions, and the product quality is stable. The product yield is increased from 80%-85% to 93-98%, and the selectivity is increased from 90%-93% to 97%-99%. At the same time, the reaction residence time is reduced, and the total reaction time is reduced from the original 15h to 2-4h, which improves the production capacity per unit time. The production cost is reduced, the environmental pollution is reduced, and it is suitable for industrial production.

Description of drawings

Figure 1 is a schematic structural diagram of the present invention.

In the figure, 1. premixer, 2. tubular reactor, 3. first tank reactor, 4. second tank reactor.

Detailed ways

Example 1

The dimethyl maleate is premixed according to the flow rate of 45L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 36L/h. The molar ratio is 1:1.20, and the residence time of the premixer is about 20s. Enter the tubular reactor, and then add the catalyst sodium methoxide solution to the tubular reactor at a flow rate of 0.2 L/h for the reaction. The reaction temperature of the tubular reactor is 25 °C and the residence time is 6 min. The dimethyl maleate is converted into The rate is about 47%, the concentration of tetramethyl phosphonate succinate is 41% (wt), and then the raw material liquid enters the tank reactor 1, and the sodium methoxide solution catalyst is added, the flow rate is 0.2L/h, and the residence time is about 0.5h, the reaction temperature was 25°C, the conversion rate of dimethyl maleate was 97%, and the concentration of tetramethyl phosphonate succinate was 89.5% (wt), and then the feed liquid entered the tank reactor 2, supplemented Sodium methoxide solution catalyst was added, the flow rate was 2.4L/h, the residence time was about 0.5h, the reaction temperature was 25°C, the conversion rate of dimethyl maleate was 99%, and the concentration of tetramethyl phosphonate succinate was 93% ( wt), the selectivity was 99%, and the dimethyl maleate in the feed was completely converted.

Example 2

The dimethyl maleate is premixed according to the flow rate of 45L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 31L/h. The molar ratio is 1:1.02, and the residence time is about 25s. Reactor, then the catalyst sodium methoxide solution was added to the tubular reactor at a flow rate of 0.8L/h for reaction. The reaction temperature of the tubular reactor was 35°C, the residence time was 7min, and the conversion rate of dimethyl maleate was about 75%. %, the concentration of tetramethyl phosphonate succinate is 65.9% (wt), then the raw material liquid enters the kettle type reactor 1, and the sodium methoxide solution catalyst is added, the flow rate is 0.8L/h, and the residence time is about 0.5h, The reaction temperature is 35°C, the conversion rate of dimethyl maleate is 99%, and the concentration of tetramethyl phosphonate succinate is 91.5% (wt), then the feed liquid enters the tank reactor 2, and sodium methoxide is added as a supplement The solution catalyst flow rate is 0.4L/h, the residence time is about 1h, the reaction temperature is 28°C, the conversion rate of dimethyl maleate is 100%, the concentration of tetramethyl phosphonate succinate is 98% (wt), and the selectivity was 99%, and the dimethyl maleate in the raw material was completely converted.

Example 3

The dimethyl maleate is premixed according to the flow rate of 25L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 18L/h, the molar ratio is 1:1.06, and the residence time is about 40s. Reactor, then the catalyst sodium methoxide solution was added to the tubular reactor at a flow rate of 0.2L/h for reaction. The reaction temperature of the tubular reactor was 26°C, the residence time was 12min, and the conversion rate of dimethyl maleate was about 65%. %, the concentration of tetramethyl phosphonate succinate is 57.9% (wt), then the raw material liquid enters the tank reactor 1, and the sodium methoxide solution catalyst is supplemented, the flow rate is 0.2L/h, and the residence time is about 1.0h, The reaction temperature is 26° C., the conversion rate of dimethyl maleate is 87%, and the concentration of tetramethyl phosphonate succinate is 83.5% (wt), then the feed liquid enters the tank reactor 2, and sodium methoxide is added as a supplement The solution catalyst flow rate is 1.5L/h, the residence time is about 1h, the reaction temperature is 28°C, the conversion rate of dimethyl maleate is 100%, the concentration of tetramethyl phosphonate succinate is 97% (wt), and the selectivity was 97%, and the dimethyl maleate in the starting material was completely converted.

Example 4

The dimethyl maleate is premixed according to the flow rate of 38L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 29L/h. The molar ratio is 1:1.13, and the residence time is about 25s. Reactor, then the catalyst sodium methoxide solution was added to the tubular reactor at a flow rate of 0.6L/h for reaction. The reaction temperature of the tubular reactor was 32°C, the residence time was 8min, and the conversion rate of dimethyl maleate was about 54%. %, the concentration of tetramethyl phosphonate succinate is 48.3% (wt), then the raw material liquid enters the tank reactor 1, and the sodium methoxide solution catalyst is supplemented, the flow rate is 0.6L/h, and the residence time is about 0.6h, The reaction temperature is 33° C., the conversion rate of dimethyl maleate is 87%, and the concentration of tetramethyl phosphonate succinate is 80.4% (wt), then the feed liquid enters the tank reactor 2, and sodium methoxide is added as a supplement The catalyst flow rate of the solution is 1.8L/h, the residence time is about 0.6h, the reaction temperature is 31°C, the conversion rate of dimethyl maleate is 99%, and the concentration of tetramethyl phosphonate succinate is 95% (wt). The property is 98%, and the dimethyl maleate in the raw material is completely converted.

Example 5

The dimethyl maleate is premixed according to the flow rate of 28L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 21L/h. The molar ratio is 1:1.11, and the residence time is about 35s. Reactor, then the catalyst sodium methoxide solution was added to the tubular reactor at a flow rate of 0.5L/h for reaction. The reaction temperature of the tubular reactor was 31°C, the residence time was 10min, and the conversion rate of dimethyl maleate was about 49%. %, the concentration of tetramethyl phosphonate succinate is 43.2% (wt), then the raw material liquid enters the tank reactor 1, and the sodium methoxide solution catalyst is supplemented, the flow rate is 0.5L/h, and the residence time is about 0.8h, The reaction temperature is 30° C., the conversion rate of dimethyl maleate is 87%, and the concentration of tetramethyl phosphonate succinate is 80.4% (wt), then the feed liquid enters the tank reactor 2, and sodium methoxide is added as a supplement The solution catalyst flow rate is 1.3L/h, the residence time is about 0.8h, the reaction temperature is 30°C, the conversion rate of dimethyl maleate is 99%, and the concentration of tetramethyl phosphonic acid succinate is 96% (wt), select The property is 97%, and the dimethyl maleate in the raw material is completely converted.

Example 6

The dimethyl maleate is premixed according to the flow rate of 33L/h, and the dimethyl phosphite is premixed by the premixer according to the flow rate of 24L/h. The molar ratio is 1:1.07, and the residence time is about 28s. Reactor, then the catalyst sodium methoxide solution was added to the tubular reactor at a flow rate of 0.2 L/h for reaction. The reaction temperature of the tubular reactor was 25 °C, the residence time was 9 min, and the conversion rate of dimethyl maleate was about 53. %, the concentration of tetramethyl phosphonate succinate is 48.7% (wt), then the raw material liquid enters the tank reactor 1, and the sodium methoxide solution catalyst is added, the flow rate is 0.4L/h, and the residence time is about 0.7h, The reaction temperature is 28° C., the conversion rate of dimethyl maleate is 79%, and the concentration of tetramethyl phosphonate succinate is 72.5% (wt), then the feed liquid enters the tank reactor 2, and sodium methoxide is added as a supplement The catalyst flow rate of the solution is 1.6L/h, the residence time is about 0.7h, the reaction temperature is 28°C, the conversion rate of dimethyl maleate is 99%, and the concentration of tetramethyl phosphonate succinate is 97% (wt). The property is 99%, and the dimethyl maleate in the raw material is completely converted.

Claims (9)

1. a continuous synthesis technique of tetramethyl phosphonic acid succinate, is characterized in that: comprise the following steps: 1) The dimethyl maleate and dimethyl phosphite are continuously transported into the premixer at a molar ratio of 1:1.02 to 1.20 for full premixing, the residence time is 20 to 40s, and then mixed with the sodium methoxide catalyst. The mixture enters the tubular reactor through the pipeline for preliminary reaction; then enters the reactor from the bottom of the tank reactor; the flow rate of dimethyl maleate is 25-45L/h, and the flow rate of dimethyl phosphite is 18-36L/h , the volume ratio of the catalyst to the volume of the raw material is 0.5%-1%; the residence time of the material in the tubular reactor is 6-12min; the reaction temperature is 25-35°C; 2) After the material undergoes preliminary pipeline reaction, it enters the first tank reactor in series, and sodium methoxide catalyst is added to ensure the reaction rate; the residence time of the material in the first tank reactor connected in series is 0.5-1.0h; the reaction The temperature is 25～35℃; the ratio of catalyst volume to raw material volume is 0.5%-1%; 3) Enter the second tank reactor in series, and add sodium methoxide catalyst to ensure the reaction rate; the residence time of the material in the second tank reactor connected in series is 0.5 ~ 1.0h; the reaction temperature is 25 ~ 35 ℃; the catalyst volume The volume ratio to the raw material is 1%-3%; the reaction product tetramethyl phosphonate succinate is obtained in the tank reactor. 2. The continuous synthesis process of tetramethyl phosphonate succinate according to claim 1, is characterized in that: in step 1), the residence time of material in the tubular reactor is 7～12min. 3. the continuous synthesis technique of tetramethyl phosphonate succinate according to claim 1, is characterized in that: in step 2), the residence time of material in the tank reactor connected in series is 0.6～1h; 3) The material is in the second tank reactor connected in series, and the residence time is 0.6～1h. 4. the continuous synthesis technique of tetramethyl phosphonate succinate according to claim 1, is characterized in that: step 1), the sodium methoxide catalyst described in step 2) is the methanol solution of sodium methoxide. 5. The continuous synthesis process of tetramethyl phosphonate succinate according to claim 4, is characterized in that: the mass concentration of sodium methoxide in the methanol solution of described sodium methoxide is 20-35%. 6. the continuous synthesis technique of tetramethyl phosphonate succinate according to claim 1, is characterized in that: step 2) is provided with stirrer in the described tank reactor. 7. the continuous synthesis process of tetramethyl phosphonate succinate according to claim 1, is characterized in that: described tubular reactor is provided with heat exchange coil, and described coil is steel pipe spiral structure, Industrial chilled water passes through the coils; a heat exchange interlayer is arranged inside the kettle-type reactor, and industrial chilled water is passed through for heat exchange. 8. the continuous synthesis technique of tetramethyl phosphonate succinate according to claim 1, is characterized in that: step 1) described dimethyl maleate and dimethyl phosphite are in premixer The residence time in 20-35s. 9. the continuous synthesis technique of tetramethyl phosphonate succinate according to claim 1, is characterized in that: the flow rate of the described catalyst of step 1) is 0.2-0.8L/h; The described catalyst of step 2) is in The flow rate in the first tank reactor was 0.2-0.8 L/h; the flow rate of the catalyst in the second tank reactor was 0.4-2.4 L/h.

Images