阅读说明：本技术 一种对二氯苯及其对二氯苯微通道连续化合成工艺 (Paradichlorobenzene and paradichlorobenzene microchannel continuous synthesis process ) 是由 刘卫卫 沈书群 徐伟 茅佳荣 秦燕 于 2021-01-11 设计创作，主要内容包括：本发明涉及对二氯苯合成领域,更具体地,本发明涉及一种对二氯苯及其对二氯苯微通道连续化合成工艺,所述对二氯苯微通道连续化合成工艺包括：将原料苯和催化剂充分混合后,作为第一股物料,氯气作为第二股物料,第一股物料和第二股物料同时进料至微通道反应器中进行氯化反应,即得。本发明定向氯化催化,原料苯转化率达100wt％,无间二氯苯生成,对邻比可高达4以上；本发明反应深度可控,三氯苯含量0.5wt％以下,原子经济性高,减少后续分离成本；本发明反应所得氯苯可再次回收进行反应,符合绿色化学理念；本发明采用微通道装置简单且易于操作,持液量少,大大降低氯化反应的安全风险、提高装置的自动化控制程度与生产效率。(The invention relates to the field of synthesis of p-dichlorobenzene, in particular to p-dichlorobenzene and a p-dichlorobenzene microchannel continuous synthesis process thereof, wherein the p-dichlorobenzene microchannel continuous synthesis process comprises the following steps: and fully mixing the raw material benzene and the catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst. The directional chlorination catalysis is carried out, the conversion rate of the raw material benzene reaches 100 wt%, no m-dichlorobenzene is generated, and the para-ortho ratio can reach more than 4; the invention has controllable reaction depth, the trichlorobenzene content is less than 0.5 wt%, the atom economy is high, and the subsequent separation cost is reduced; the chlorobenzene obtained by the reaction can be recycled for reaction again, and the green chemical concept is met; the invention adopts the microchannel device, is simple and easy to operate, has small liquid holdup, greatly reduces the safety risk of chlorination reaction, and improves the automation control degree and the production efficiency of the device.)

1. A p-dichlorobenzene microchannel continuous synthesis process is characterized by comprising the following steps: and fully mixing the raw material benzene and the catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

2. The continuous p-dichlorobenzene synthesis process according to claim 1, comprising: the method comprises the steps of fully mixing raw materials of benzene, chlorobenzene and a catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

3. The continuous p-dichlorobenzene synthesis process according to claim 2, wherein the reaction module of said microchannel reactor is greater than or equal to 2.

4. The continuous p-dichlorobenzene synthesis process according to claim 3, wherein said first material feeding flow rate is 5-15 mL/min.

5. The continuous p-dichlorobenzene synthesis process according to claim 4, wherein the weight ratio of the second material to the first material is (0.8-1.5): 1.

6. the continuous p-dichlorobenzene synthesis process according to any one of claims 2-5, wherein said first material stream comprises benzene and chlorobenzene in a weight ratio of (0.5-1.5): 1.

7. the continuous p-dichlorobenzene synthesis process according to claim 6, wherein said catalyst is 0.1-1 wt% of the first material.

8. The continuous p-dichlorobenzene synthesis process according to claim 7, wherein said catalyst is metal catalyst selected from one or more of iron powder, lead powder and antimony powder.

9. The continuous p-dichlorobenzene synthesis process according to claim 8, wherein the metal catalyst is lead powder and antimony powder, and the weight ratio of the metal catalyst to the metal catalyst is 1: (1-5).

10. A p-dichlorobenzene prepared according to the p-dichlorobenzene microchannel continuous synthesis process of any one of claims 1-9.

Technical Field

The invention relates to the field of synthesis of p-dichlorobenzene, and particularly relates to p-dichlorobenzene and a p-dichlorobenzene microchannel continuous synthesis process thereof.

Background

The p-dichlorobenzene is also called 1, 4-dichlorobenzene, is called PDCB for short, can be used for engineering plastics, synthetic pesticides and medicines, and is an intermediate with wide application. At present, the industrial production of p-dichlorobenzene at home and abroad mainly adopts the directional catalytic chlorination of benzene and is divided into two methods, namely a batch method and a continuous method. The intermittent method has a series of problems of high storage capacity, poor heat transfer effect, low yield, high safety risk and the like. The continuous method still has the defects of poor mass transfer and heat transfer efficiency, complex operation and the like, and the reaction speed cannot be accurately controlled, so that the components of the obtained chlorination liquid are complex, the separation is difficult, and the production cost is increased. Therefore, the method is particularly important for researching a novel continuous chlorination process with high mass and heat transfer, simplicity, safety and controllability.

Disclosure of Invention

In view of the problems in the prior art, the first aspect of the present invention provides a continuous synthesis process of p-dichlorobenzene microchannels, comprising: and fully mixing the raw material benzene and the catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

As a preferred technical scheme of the invention, the continuous chemical synthesis process of the p-dichlorobenzene microchannel comprises the following steps: the method comprises the steps of fully mixing raw materials of benzene, chlorobenzene and a catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

In a preferred embodiment of the present invention, the reaction module of the microchannel reactor is greater than or equal to 2.

As a preferred technical scheme of the invention, the flow rate of the first material feeding is 5-15 mL/min.

As a preferable technical scheme of the invention, the weight ratio of the second strand of material to the first strand of material is (0.8-1.5): 1.

as a preferred technical solution of the present invention, in the first stream of material, the weight ratio of benzene to chlorobenzene is (0.5-1.5): 1.

as a preferred technical scheme of the invention, the catalyst accounts for 0.1-1 wt% of the first material.

As a preferred technical solution of the present invention, the catalyst is a metal catalyst, and is selected from one or more of iron powder, lead powder, and antimony powder.

As a preferred technical scheme of the invention, the metal catalyst is lead powder and antimony powder, and the weight ratio of the lead powder to the antimony powder is 1: (1-5).

The invention also provides a preparation method of the p-dichlorobenzene micro-channel continuous chemical synthesis process.

Compared with the prior art, the invention has the following beneficial effects:

(1) the directional chlorination catalysis is carried out, the conversion rate of the raw material benzene reaches 100 wt%, no m-dichlorobenzene is generated, and the para-ortho ratio can reach more than 4;

(2) the invention has controllable reaction depth, the trichlorobenzene content is less than 0.5 wt%, the atom economy is high, and the subsequent separation cost is reduced;

(3) the chlorobenzene obtained by the reaction can be recycled for reaction again, and the green chemical concept is met;

(4) the invention adopts the microchannel device, is simple and easy to operate, has small liquid holdup, greatly reduces the safety risk of chlorination reaction, and improves the automation control degree and the production efficiency of the device.

Drawings

FIG. 1 is a flow chart of a continuous synthesis process of p-dichlorobenzene by micro-channels.

Detailed Description

The invention provides a p-dichlorobenzene microchannel continuous synthesis process, which comprises the following steps: and fully mixing the raw material benzene and the catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

In one embodiment, the p-dichlorobenzene microchannel continuous synthesis process comprises: the method comprises the steps of fully mixing raw materials of benzene, chlorobenzene and a catalyst to obtain a first material, taking chlorine as a second material, and simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction to obtain the catalyst.

Preferably, the reaction module of the microchannel reactor is greater than or equal to 2; more preferably, the microchannel reactor has a reaction module of 2.

When the reaction module of the microchannel reactor is 2, the microchannel reactor is convenient to operate, can ensure high conversion rate of benzene and can ensure higher directional conversion rate of p-dichlorobenzene.

Preferably, the flow rate of the first material feeding is 5-15 mL/min; more preferably, the flow rate of the first material feed is 5 mL/min.

Preferably, the flow rate of the second material feeding is 5-15 mL/min; more preferably, the flow rate of the first material feed is 6 mL/min.

The invention controls the flow of the first material and the second material, and can effectively avoid the generation of m-dichlorobenzene.

Preferably, the weight ratio of the second strand of material to the first strand of material is (0.8-1.5): 1, more preferably, the weight ratio of the second material to the first material is 1: 1.

preferably, in the first material, the weight ratio of benzene to chlorobenzene is (0.5-1.5): 1; further preferably, in the first strand of material, the weight ratio of benzene to chlorobenzene is (1-1.5): 1; more preferably, the weight ratio of benzene to chlorobenzene in the first stream of material is 1: 1.

according to the invention, chlorobenzene with a certain content is introduced in the reaction process, so that the generation rate of p-dichlorobenzene is accelerated, the conversion rate of benzene is increased, and the reaction of benzene and chlorobenzene is carried out simultaneously.

Preferably, the catalyst accounts for 0.1-1 wt% of the first material; further preferably, the catalyst accounts for 0.1-0.3 wt% of the first material; more preferably, the catalyst comprises 0.1 wt% of the first stream.

Preferably, the catalyst is a metal catalyst selected from one or more of iron powder, lead powder and antimony powder.

Further preferably, the catalyst is lead powder and antimony powder, and the weight ratio of the lead powder to the antimony powder is 1: (1-5); more preferably, the weight ratio of the lead powder to the antimony powder is 1: 2.7.

in the experiment, the invention discovers that the selectivity of p-dichlorobenzene is low although the catalyst is cheap and easy to obtain, however, the applicant unexpectedly discovers that when the flow rate of the first material is 5-15mL/min, and the weight ratio of benzene to chlorobenzene in the first material is (0.5-1.5): 1, when the metal catalyst is lead powder and antimony powder, particularly the weight ratio of the lead powder to the antimony powder is 1: (1-5) the selectivity to p-chlorobenzene was improved, the weight ratio of p-dichlorobenzene to o-dichlorobenzene was more than 4, and the trichlorobenzene content was 0.5 wt% or less.

In one embodiment, the first stream and the second stream are simultaneously fed into a microchannel reactor to carry out chlorination reaction at 40-80 ℃.

Preferably, the first material and the second material are simultaneously fed into the microchannel reactor to carry out chlorination reaction at 60-70 ℃.

In one embodiment, the microchannel reactor is a G1-size cardioid high throughput microchannel reactor available from corning corporation.

In one embodiment, as shown in FIG. 1, the p-dichlorobenzene microchannel continuous synthesis process comprises: fully mixing raw material benzene and a catalyst to obtain a first material, taking chlorine as a second material, simultaneously feeding the first material and the second material into a microchannel reactor for chlorination reaction, carrying out falling film dehydrogenation on the obtained reaction liquid, then feeding the reaction liquid into a rectifying tower for separation to obtain crude dichlorobenzene, and then carrying out crystallization separation to obtain the catalyst.

The crude dichlorobenzene crystal can be separated to obtain 99.95 wt% of p-dichlorobenzene.

The microchannel reactor of the invention is a G1 standard heart-shaped microchannel reactor, and is purchased from Corning Corp.

The invention also provides a preparation method of the p-dichlorobenzene micro-channel continuous chemical synthesis process.

The para-ortho ratio is the weight ratio of para-dichlorobenzene to ortho-dichlorobenzene.

Examples

Hereinafter, the present invention will be described in more detail by way of examples, but it should be understood that these examples are merely illustrative and not restrictive. The starting materials used in the examples which follow are all commercially available unless otherwise stated.

Example 1

The embodiment 1 of the invention provides a p-dichlorobenzene microchannel continuous synthesis process, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, adding 0.3g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 70 ℃, controlling the flow rate of a first strand of material to be 5mL/min, controlling the flow rate of a second strand of material to be 6mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is lead powder and antimony powder, and the weight ratio is 1: 2.7.

the gas chromatography detection analysis shows that the reaction solution comprises 15.25 wt% of chlorobenzene, 67.49 wt% of p-dichlorobenzene, 16.83 wt% of o-dichlorobenzene and 0.43 wt% of trichlorobenzene, the conversion rate of the raw material benzene is 100 wt%, and no m-dichlorobenzene is generated.

Example 2

The embodiment 2 of the invention provides a p-dichlorobenzene microchannel continuous synthesis process, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, simultaneously adding 0.4g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 60 ℃, controlling the flow rate of a first strand of material to be 5mL/min, controlling the flow rate of a second strand of material to be 6mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is lead powder and antimony powder, and the weight ratio is 1: 5.

the gas chromatography detection analysis shows that the reaction solution comprises 16.16 wt% of chlorobenzene, 67.33 wt% of p-dichlorobenzene, 16.02 wt% of o-dichlorobenzene, 0.43 wt% of trichlorobenzene, 100 wt% of conversion rate of raw material benzene and no generation of m-dichlorobenzene.

Example 3

The embodiment 3 of the invention provides a p-dichlorobenzene microchannel continuous synthesis process, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, adding 0.3g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 70 ℃, controlling the flow rate of a first strand of material to be 5mL/min, controlling the flow rate of a second strand of material to be 6mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is lead powder.

The composition of the reaction solution was analyzed by gas chromatography for 23.29 wt% of p-dichlorobenzene.

Example 4

Embodiment 4 of the present invention provides a continuous synthesis process of p-dichlorobenzene microchannels, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, adding 0.3g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 70 ℃, controlling the flow rate of a first strand of material to be 5mL/min, controlling the flow rate of a second strand of material to be 6mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is lead powder and fluorite, and the weight ratio is 1: 2.7.

the composition of the reaction solution was analyzed by gas chromatography for 35.72 wt% of p-dichlorobenzene.

Example 5

Embodiment 5 of the present invention provides a continuous synthesis process of p-dichlorobenzene microchannels, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, adding 0.3g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 70 ℃, controlling the flow rate of a first strand of material to be 5mL/min, controlling the flow rate of a second strand of material to be 6mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is antimony powder.

The reaction solution was analyzed by GC analysis for 33.68 wt% of p-dichlorobenzene in the composition.

Example 6

Embodiment 6 of the present invention provides a continuous synthesis process of p-dichlorobenzene microchannels, which comprises the following specific steps:

(1) weighing 100g of benzene and 100g of chlorobenzene, adding 0.3g of catalyst, fully mixing to obtain a first strand of material, taking chlorine as a second strand of material, decompressing by a steel cylinder, and introducing by a mass flow meter;

(2) after the temperature of the microchannel reactor is set at 70 ℃, controlling the flow rate of a first strand of material to be 2mL/min, controlling the flow rate of a second strand of material to be 3mL/min, wherein the weight ratio of the second strand of material to the first strand of material is 1: 1;

(3) and (3) after each strand of material in the microchannel reactor reaches a stable state, collecting the reaction liquid flowing out of the outlet of the reactor to obtain the product.

The catalyst is lead powder and antimony powder, and the weight ratio is 1: 2.7.

the reaction solution composition was analyzed by gas chromatography for 48.23 wt% of p-dichlorobenzene.

The foregoing examples are merely illustrative and serve to explain some of the features of the method of the present invention. The appended claims are intended to claim as broad a scope as is contemplated, and the examples presented herein are merely illustrative of selected implementations in accordance with all possible combinations of examples. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the invention. Also, where numerical ranges are used in the claims, subranges therein are included, and variations in these ranges are also to be construed as possible being covered by the appended claims.