阅读说明：本技术 一种采用微通道反应器合成异氰酸正丁酯的方法 (Method for synthesizing n-butyl isocyanate by using microchannel reactor ) 是由 石苏洋 严绘 孟海娟 廖强 王明晨 马荣慧 于 2021-10-18 设计创作，主要内容包括：本发明公开了一种采用微通道反应器合成异氰酸正丁酯的方法,所述方法包括以下步骤：正丁胺与溶剂配制成正丁胺溶液,在反应温度下将正丁胺溶液与氯化氢同时通入微通道反应器成盐板块内进行成盐反应生成成盐液；上述步骤产生的成盐液与光气在反应温度、压力下通入微通道反应器光气化板块内进行光气化反应,合成液经赶光后取样分析含量。本发明通过微通道反应器,实现成盐及光气化反应的连续化,可连续制备异氰酸正丁酯。光气利用率高,副反应少,产品收率高,同时微通道反应器持液体积小,反应安全性较传统釜式反应大幅提高。(The invention discloses a method for synthesizing n-butyl isocyanate by adopting a microchannel reactor, which comprises the following steps: preparing n-butylamine solution from n-butylamine and a solvent, and introducing the n-butylamine solution and hydrogen chloride into a microchannel reactor salifying plate at the same time at a reaction temperature to perform salifying reaction to generate salt solution; and (3) introducing the salified solution and phosgene generated in the step into a phosgenation slab block of a microchannel reactor at the reaction temperature and under the reaction pressure for phosgenation reaction, and sampling and analyzing the content of the synthetic solution after polishing. The invention realizes the continuity of salification and phosgenation reaction by a microchannel reactor and can continuously prepare the n-butyl isocyanate. The phosgene utilization rate is high, the side reaction is less, the product yield is high, the liquid holding volume of the microchannel reactor is small, and the reaction safety is greatly improved compared with the traditional kettle type reaction.)

1. A method for synthesizing n-butyl isocyanate by using a microchannel reactor is characterized by comprising the following steps:

(1) preparing n-butylamine solution from n-butylamine and a solvent, and introducing the n-butylamine solution and hydrogen chloride into a microchannel reactor salifying plate at the same time at a reaction temperature to perform salifying reaction to generate salt solution;

(2) and (3) introducing the salified solution and phosgene generated in the step into a phosgenation slab block of a microchannel reactor at the reaction temperature and under the reaction pressure for phosgenation reaction, and sampling and analyzing the content of the synthetic solution after polishing.

2. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the solvent in the step (1) is one of dichloroethane, toluene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene and p-dichlorobenzene, preferably o-dichlorobenzene.

3. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the concentration of the n-butylamine solution in the step (1) is 5 to 40%, preferably 5 to 15%.

4. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the reaction temperature in the step (1) is 0 ℃ to 60 ℃, preferably 10 ℃ to 30 ℃.

5. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein in the step (1), the n-butylamine solution and the hydrogen chloride are simultaneously introduced into the salt-forming plate of the microchannel reactor to perform the salt-forming reaction for a retention time of 10-300 s, preferably 50-100 s.

6. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the molar ratio of the hydrogen chloride to the n-butylamine solution in the step (1) is 1.1-1.5: 1, preferably 1.1-1.2: 1.

7. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the molar ratio of the phosgene to the salt forming solution in the step (2) is 1.1-2.0: 1, preferably 1.2-1.3: 1.

8. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the temperature of the reaction in the step (2) is 70 to 150 ℃, preferably 90 to 110 ℃.

9. The method for synthesizing n-butyl isocyanate by using a microchannel reactor as claimed in claim 1, wherein the residence time of the phosgenation reaction in the step (2) is 10-600 s, preferably 100-200 s.

10. The method for synthesizing n-butyl isocyanate by using the microchannel reactor as claimed in claim 1, wherein the pressure of the reaction in the step (2) is 0.1 to 1.0MPa, preferably 0.3 to 0.5 MPa.

Technical Field

The invention relates to the field of organic synthesis, in particular to a method for synthesizing n-butyl isocyanate by adopting a microchannel reactor.

Background

N-butyl isocyanate (hereinafter referred to as FNC) is mainly used for synthesizing pesticides such as benomyl and the like, and is also used as a catalyst for synthesizing sulfonylurea herbicides. Is an important intermediate and can be used for synthesizing products such as medicines, pesticides and the like. The prior FNC preparation method mainly comprises a phosgene low-temperature high-temperature two-step method and a salt formation first and light introduction second method. The reaction formulas of the two synthetic methods are as follows:

(1) the low-temperature high-temperature two-step reaction formula is as follows:

a low-temperature section:

a high-temperature section:

(2) the reaction formula of salifying first and then introducing light is as follows:

the low-temperature and high-temperature two-step method has long reaction time, more side reactions and low yield; the method of salifying first and then introducing phosgene is adopted, active amino groups are protected, and the yield is obviously improved. However, the two methods adopt intermittent reaction industrially, and have the defects of long reaction time, low phosgene utilization rate, easy self-polymerization of materials due to long-time high-temperature heating and the like.

Patent CN105294498A describes a FNC synthesis method. The FNC is prepared by a two-step method of low temperature and high temperature. The method is intermittent operation, the reaction time is long, and FNC is easy to self-polymerize after being heated for a long time, so that the appearance and the yield of the product are influenced.

Patent CN103848759A describes a method for synthesizing FNC by first forming salt and then phosgene. The reaction yield is high, but the method still adopts intermittent reaction and has the defects of long reaction time, unstable FNC heated for a long time and the like. Meanwhile, the intermittent reaction has the defects of high labor intensity, low productivity, unstable yield and product quality and the like.

The invention introduces a method for synthesizing FNC by using a microchannel reactor, which has the advantages that the method can better improve the phosgene utilization rate, simultaneously ensure the conversion rate of n-butylamine and reduce the generation of byproducts, thereby improving the yield and selectivity of final products; because the micro-reaction retention time is short, the mass and heat transfer effects are good, and the self-aggregation of the FNC caused by long-time heating can be greatly reduced. The method can continuously prepare FNC, and is suitable for industrial production.

Disclosure of Invention

The invention provides a method for synthesizing n-butyl isocyanate by adopting a microchannel reactor, aiming at the problems in the prior art, when in application, n-butylamine solution and hydrogen chloride are pumped into a microchannel reactor (micro-reaction for short) to form a salt forming plate to form n-butylamine hydrochloride solution, phosgene and the salt forming solution continuously enter a micro-reflection gasification plate to react, and the n-butyl isocyanate synthetic solution is prepared. The invention realizes the continuity of salification and phosgenation reaction by a microchannel reactor and can continuously prepare the n-butyl isocyanate. The phosgene utilization rate is high, the side reaction is less, the product yield is high, the liquid holding volume of the microchannel reactor is small, and the reaction safety is greatly improved compared with the traditional kettle type reaction.

The invention is realized by the following technical scheme:

a method for synthesizing n-butyl isocyanate by using a microchannel reactor, the method comprising the steps of:

(1) preparing n-butylamine solution from n-butylamine and a solvent, and introducing the n-butylamine solution and hydrogen chloride into a microchannel reactor salifying plate at the same time at a reaction temperature to perform salifying reaction to generate salt solution;

(2) and (3) introducing the salified solution and phosgene generated in the step into a phosgenation slab block of a microchannel reactor at the reaction temperature and under the reaction pressure for phosgenation reaction, and sampling and analyzing the content of the synthetic solution after polishing.

Further, the method for synthesizing n-butyl isocyanate by using the microchannel reactor is characterized in that the solvent in the step (1) is one of dichloroethane, toluene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene and p-dichlorobenzene, preferably o-dichlorobenzene.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the advantage that the concentration of the n-butylamine solution in the step (1) is 5-40%, preferably 5-15%.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the reaction temperature of 0-60 ℃ in the step (1), and preferably 10-30 ℃.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor is characterized in that in the step (1), the n-butylamine solution and the hydrogen chloride are simultaneously introduced into a salt forming plate of the microchannel reactor to carry out salt forming reaction for a retention time of 10-300 s, preferably 50-100 s.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the advantage that the molar ratio of the hydrogen chloride to the n-butylamine solution in the step (1) is 1.1-1.5: 1, preferably 1.1-1.2: 1.

Further, the method for synthesizing n-butyl isocyanate by adopting the microchannel reactor comprises the step (2) that the molar ratio of phosgene to salt forming liquid is 1.1-2.0: 1, and preferably 1.2-1.3: 1.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the reaction temperature of 70-150 ℃ in the step (2), and preferably 90-110 ℃.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the advantage that the residence time of the phosgenation reaction in the step (2) is 10-600 s, and preferably 100-200 s.

Further, the method for synthesizing the n-butyl isocyanate by adopting the microchannel reactor has the pressure of the reaction in the step (2) of 0.1-1.0 MPa, preferably 0.3-0.5 MPa.

In summary, the following beneficial effects of the invention are:

1. the invention relates to a method for synthesizing n-butyl isocyanate by adopting a microchannel reactor, which adopts the microchannel reactor to complete salification and phosgenation continuous preparation of FNC, has short process flow and low labor intensity, greatly improves the productivity and is suitable for industrial production;

2. the method for synthesizing n-butyl isocyanate by adopting the microchannel reactor has the advantages that the feeding proportion of the microchannel reactor is accurate, the mass transfer and heat transfer effects are excellent, meanwhile, the FNC is prepared by salifying first and then carrying out the phosgenation reaction, the active amino group is protected, the conversion rate and the selectivity are greatly improved compared with those of the conventional kettle type reaction, and the utilization rate of phosgene is greatly improved by adopting the pressurization reaction in the phosgenation reaction process;

3. the invention relates to a method for synthesizing n-butyl isocyanate by adopting a microchannel reactor, wherein the phosgenation reaction belongs to a dangerous process, the liquid holding volume of the microchannel reactor is small, and the intrinsic safety is greatly improved compared with the traditional kettle type reaction.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic view of the process of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.

Example 1

As shown in figure 1, preparing a 10% n-butylamine-o-dichlorobenzene liquid, and introducing the n-butylamine-o-dichlorobenzene liquid and hydrogen chloride into a microchannel reactor simultaneously for salification according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.2:1, wherein the salification temperature is 20 ℃ and the retention time is 50 s; (2) continuously introducing n-butylamine hydrochloride-o-dichlorobenzene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 1.3: 1. The pressure of the reaction system is kept at 0.5MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 95 ℃ by a heat exchanger, and the retention time is 100 s. The synthetic liquid is obtained after the reaction, and after the light-emitting, the synthetic liquid is sent to be analyzed, the normalized content of FNC in the synthetic liquid is 99.2 percent, and the yield of FNC is 98.1 percent.

Example 2

As shown in figure 1, preparing a 5% n-butylamine-chlorobenzene solution, and introducing the n-butylamine-chlorobenzene solution and hydrogen chloride into a microchannel reactor simultaneously for salification according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.1:1, wherein the salification temperature is 10 ℃ and the retention time is 200 s. (2) Continuously introducing n-butylamine hydrochloride-chlorobenzene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 1.2: 1. The pressure of a reaction system is kept at 0.30MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 120 ℃ by a heat exchanger, the retention time is 300s, synthetic liquid is obtained by reaction, and the synthetic liquid is sent to a sample for analysis after being polished. The FNC normalization content in the synthetic liquid is 98.5%, and the FNC yield is 97.8%.

Example 3

As shown in figure 1, preparing a 15% n-butylamine-toluene solution, introducing the n-butylamine-toluene solution and hydrogen chloride into a microchannel reactor simultaneously according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.5:1 for salifying, wherein the salifying temperature is 30 ℃, and the retention time is 100 s. (2) Continuously introducing the n-butylamine hydrochloride-toluene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 1.5: 1. The pressure of a reaction system is kept at 0.20MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 110 ℃ by a heat exchanger, the retention time is 200s, synthetic liquid is obtained by reaction, and the synthetic liquid is sent to a sample for analysis after being polished. The FNC normalization content in the synthetic liquid is 99.5%, and the FNC yield is 98.7%.

Example 4

As shown in figure 1, preparing 40% n-butylamine-o-dichlorobenzene liquid, and introducing the n-butylamine-o-dichlorobenzene liquid and hydrogen chloride into a microchannel reactor simultaneously for salification according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.2:1, wherein the salification temperature is 50 ℃ and the retention time is 100 s. (2) Continuously introducing n-butylamine hydrochloride-o-dichlorobenzene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 2.0: 1. The pressure of a reaction system is kept at 1.0MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 130 ℃ by a heat exchanger, the retention time is 600s, synthetic liquid is obtained by reaction, and the synthetic liquid is sent to a sample for analysis after being polished. The FNC normalization content in the synthetic liquid is 97.8%, and the FNC yield is 97.1%.

Example 5

As shown in figure 1, preparing 30% n-butylamine-o-dichlorobenzene liquid, and introducing the n-butylamine-o-dichlorobenzene liquid and hydrogen chloride into a microchannel reactor simultaneously for salification according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.3:1, wherein the salification temperature is 40 ℃ and the retention time is 300 s. (2) Continuously introducing n-butylamine hydrochloride-o-dichlorobenzene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 1.8: 1. The pressure of a reaction system is kept at 0.7MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 70 ℃ by a heat exchanger, the retention time is 60s, synthetic liquid is obtained by reaction, and the synthetic liquid is sent to a sample for analysis after being polished. The FNC normalization content in the synthetic liquid is 97.1%, and the FNC yield is 96.5%.

Example 6

As shown in figure 1, preparing 20% n-butylamine-m-dichlorobenzene liquid, and introducing the n-butylamine-m-dichlorobenzene liquid and hydrogen chloride into a microchannel reactor simultaneously for salification according to the molar ratio of the hydrogen chloride to the n-butylamine being 1.2:1, wherein the salification temperature is 20 ℃ and the retention time is 150 s. (2) Continuously introducing n-butylamine hydrochloride-m-dichlorobenzene liquid and phosgene into a phosgenation plate for a phosgenation reaction, wherein the phosgene ratio is as follows: the molar ratio of n-butylamine hydrochloride was 1.4: 1. The pressure of a reaction system is kept at 0.25MPa by adjusting a back pressure valve at the outlet of the reactor, the reaction temperature is controlled at 100 ℃ by a heat exchanger, the retention time is 150s, synthetic liquid is obtained by reaction, and the synthetic liquid is sent to a sample for analysis after being polished. The FNC normalization content in the synthetic liquid is 98.3%, and the FNC yield is 97.7%.

Comparative example 1

Salt formation is carried out firstly, then light gas is introduced for intermittent reaction to synthesize FNC, and 10% n-butylamine-o-dichlorobenzene liquid is prepared. Continuously introducing hydrogen chloride into the n-butylamine o-dichlorobenzene solution for salt forming reaction at the salt forming temperature of 10 ℃ for 3 hours. And heating the salt forming solution to 95 ℃, continuously introducing phosgene, and introducing light until the reaction solution is clear. Phosgene: the molar ratio of n-butylamine to n-butylamine is 1.8:1, and the light-on time is 8 h. After the synthetic liquid is subjected to polishing, the synthetic liquid is subjected to sample analysis, the normalized FNC content is 86.3%, and the FNC yield is 85.2%.

Comparative example 2

Adopting a microchannel reactor to synthesize FNC by one-step method, preparing 10% n-butylamine-o-dichlorobenzene liquid, and introducing the n-butylamine-o-dichlorobenzene liquid and phosgene into the microchannel reactor simultaneously according to the mol ratio of the phosgene to the n-butylamine being 1.8: 1. The pressure of the reaction system was maintained at 0.5MPa by adjusting a back pressure valve at the outlet of the reactor. Controlling the reaction temperature to be 95 ℃ through a heat exchanger, controlling the reaction residence time to be 100s, reacting to obtain synthetic liquid, and sending the synthetic liquid to a sample for analysis after polishing. The FNC normalization content in the synthetic liquid is 92.5 percent, and the FNC yield is 91.3 percent.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.